A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the Murray-Darling Basin
Report to the Murray- Darling Basin Commission
Funded by the Strategic Investigations and Education Riverine Program - Project R2006
Freshwater Ecology, Arthur Rylah Institute for Environmental Research, Keith Turnbull Research Institute & Dr Jane Roberts
February 2002 A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the Murray-Darling Basin.
Report produced for Murray-Darling Basin Commission, Strategic Investigations and Riverine Program – Project R2006.
Prepared by Pam Clunie1, Ivor Stuart1, Matthew Jones1, Di Crowther1, Sabine Schreiber1, Shanaugh McKay1, Justin O'Connor1, & David McLaren2, John Weiss2, Lalith Gunasekera2 & Dr. Jane Roberts3
1 Arthur Rylah Institute for Environmental Research, DNRE 2 Keith Turnbull Research Institute, DNRE 3 Consultant
Published by: Department of Natural Resources and Environment Arthur Rylah Institute 123 Brown Street Heidelberg, Victoria, 3084
February 2002
Copyright State Government of Victoria, Department of Natural Resources and Environment 2002.
ISBN http://resourceweb/corpmgt/webservices/online.htm
Cover Photos: Potamopyrgus antipodarum Steve Morton Salvinia molesta John Weiss Cyprinus carpio Matthew Jones Salix sp. Phil Papas
This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Table of Contents
TABLE OF CONTENTS...... I
LIST OF FIGURES ...... III LIST OF TABLES...... III
EXECUTIVE SUMMARY ...... V
CONTEXT...... V OBJECTIVES, TASKS AND OUTPUTS ...... V RISK ASSESSMENT ...... VI EDUCATION ...... VI CANVASSING EXPERT OPINION...... VII RESEARCH PORTFOLIO...... VIII
1 INTRODUCTION ...... 1
1.1 BACKGROUND...... 1 1.2 OBJECTIVES ...... 1 1.3 DEFINITIONS - WHAT IS A PEST ? ...... 1 2 RISK ASSESSMENTS...... 7
2.1 AQUATIC AND RIPARIAN WEED RISK ASSESSMENT ...... 7 2.2 RISK ASSESSMENT FOR PEST FAUNA...... 24 3 REVIEW OF EDUCATIONAL MATERIAL...... 28
3.1 METHODS...... 28 3.2 RESULTS/OUTPUTS ...... 28 3.3 CONCLUSIONS AND RECOMMENDATIONS ...... 36 3.4 MURRAY-DARLING BASIN INVASIVE SPECIES EDUCATION PROGRAM ...... 37 4 IDENTIFICATION OF CURRENT AND POTENTIAL PEST SPECIES - FAUNA...... 40
4.1. METHODS...... 40 4.2 QUESTIONS AND ANSWERS...... 42 5 IDENTIFYING CURRENT AND POTENTIAL PEST PLANT SPECIES ...... 56
5.1 IDENTIFICATION...... 56 5.2 MANAGEMENT ISSUES...... 57 5.3 RESEARCH; INFORMATION & EDUCATION ...... 57 5.4 BUILDING ON THE QUESTIONNAIRE...... 60
6 SPECIES’ PROFILES ...... 63
6.1 FISH...... 64 6.1.1: Cyprinus carpio (Carp) ...... 64 6.1.2: Gambusia holbrooki (Eastern Gambusia) ...... 67 6.1.3: Carassius auratus (Goldfish)...... 71 6.1.4: Perca fluviatilis (Redfin)...... 74
i 6.1.5: Misgurnus anguillicaudatus (Oriental Weatherloach) ...... 77 6.1.6: Salmo trutta (Brown Trout)...... 80 6.1.7: Oreochromis mossambicus (Mozambique Tilapia) ...... 83 6.1.8: Oncorhynchus mykiss (Rainbow Trout) ...... 85 6.1.9: Tinca tinca (Tench)...... 88 6.1.10: Rutilius rutilius (Roach) ...... 90 6.1.11: Poecilia reticultata (Guppy)...... 92 6.1.12: Salmo salar (Atlantic Salmon) ...... 94 6.1.13: Salvelinus fontinalis (Brook Trout)...... 96 6.2 INVERTEBRATES...... 98 6.2.1 Cherax tenuimanus (Marron)...... 98 6.2.2 Pseudosuccinea columella (American ribbed fluke snail)...... 100 6.2.3 Potamopyrgus antipodarum (New Zealand mudsnail) ...... 102 6.2.4 Dreissena polymorpha (Zebra mussel)...... 104 6.3 PLANTS ...... 106 6.3.1 Lippia Phyla canescens (Kunth) E.Greene ...... 106 6.3.2 Willows (Salix spp.) ...... 109 7 RESEARCH PROJECTS: BRIEFS ...... 113
7.1 METHODS...... 113 7.2 DEVELOPMENT AND SCOPE OF PROJECTS ...... 113 7.3 OUTLINE AND SUMMARY OF PROJECTS ...... 114 7.4 RESEARCH PROJECT BRIEFS ...... 116 7.4.1 Research Project Brief 1: An Educational Strategy for Biological Invasions...... 119 7.4.2 Research Project Brief 2: A Generic Framework for Managing Biological Invasions ...... 124 7.4.3 Research Project Brief 3: A Rapid Response System for New Species Introductions...... 127 7.4.4 Research Project Brief 4: A Coordinated Approach to Managing Programs for Controlling Biological Invasions ...... 131 7.4.5 Research Project Brief 5: Towards Improved Water Quality and Biodiversity through Integrated Weed Management in Riverine Ecosystems ...... 136 7.4.6 Research Project Brief 6: A Review of Translocated Species and Their Distribution ...... 139 7.4.7 Research Project Brief 7: Risk Assessment for Exotic and Alien Flora and Fauna...... 142 7.4.8 Research Project Brief 8: Addressing Barriers and Knowledge Gaps Crucial for Effective Willow Management in south-eastern Australia ...... 145 7.4.9 Research Project Brief 9: Lippia as a Problem Species in the Riparian Zone and on Floodplains ...... 149 7.4.10 Research Project Brief 10: Integrated Control of Blackberry...... 153 7.4.12 Research Project Brief 12: Research and Management of Gambusia...... 159 7.4.13 Research Project Brief 13: Testing the Effectiveness of Carp Eradication and Control Techniques...... 179 7.4.14 Research Project Brief 14: Determination of the Distribution of Alien Species ...... 182 7.4.15 Research Project Brief 15: Assessment of Ecological Impacts of Alien and Exotic Species...... 187 7.4.16 Research Project Brief 16: Research and Management of Exotic Pathogens...... 190 ii 7.4.17 Research Project Brief 17: Investigation of Potential Biological Control Technologies for Alien and Exotic Species ...... 194 7.4.18 Research Project Brief 18: Assessment of the Effectiveness of Habitat Restoration as a Method for Controlling Biological Invasions...... 202 8. REFERENCES ...... 206
9. PERSONAL COMMUNICATIONS ...... 217
10. ACKNOWLEDGEMENTS...... 219
11. APPENDICES...... 220
APPENDIX 1: FAUNA QUESTIONNAIRE...... 220 APPENDIX 2: WEED RISK ASSESSMENT ...... 229 APPENDIX 3: PEST PLANT QUESTIONNAIRE: QUESTIONS AND ANSWERS...... 233
List of Figures Figure 1: Temporal stages of an invasion...... 6 Figure 2: Hierarchy for determining aquatic (and riparian) weed risk...... 12 Figure 3: Full aquatic weed hierarchy...... 13 Figure 4: Weed assessment involving unweighted criteria...... 17 Figure 5: Weed assessment involving weighted criteria ...... 17 Figure 6: Total social cost of plant invasion in relation to timing of intervention: early versus late..... 21 Figure 7: Theoretical increase in relative abundance over time by an invading plant species and chance of eradication...... 21 Figure 8: Interim Biogeographical Regional Units for the MDB...... 23 Figure 9: Hierarchy for determining pest fish risk ...... 27 Figure 10: The distribution of Carp Cyprinus carpio in the MDB...... 64 Figure 11: The distribution of Gambusia Gambusia holbrooki in the MDB ...... 67 Figure 12: The distribution of Goldfish Carassius auratus in the MDB...... 71 Figure 13: The distribution of Redfin Perca fluviatilis in the MDB...... 74 Figure 14: The distribution of Oriental Weatherloach Misgurnus anguillicaudatus in the MDB ...... 77 Figure 15: The distribution of Brown Trout Salmo trutta in the MDB ...... 80 Figure 16: The distribution of Rainbow Trout Oncorhynchus mykiss in the MDB...... 85 Figure 17: The distribution of Tench Tinca tinca in the MDB...... 88 Figure 18: Linkages between projects ...... 118
List of Tables Table 1: AHP steps, as described by Saaty ...... 10 Table 2: Invasiveness assessment scores for 22 sample species in the MDB...... 15 Table 3: Impact assessment scores for the 22 sample species in the MDB...... 16 Table 4: Ranking weeds from highest to lower priority ...... 18 Table 5: The 22 sample species grouped according to their invasive and impact potential ...... 19
iii Table 6: Circulation list for fauna questionnaire ...... 40 Table 7: Current and potential aquatic pest fish species in the MDB ...... 43 Table 8: Management and research options for aquatic pest fish species...... 46 Table 9: Stakeholders' assessment of seven species nominated for single species research ...... 59 Table 10: Summary of projects ...... 117
iv Executive Summary
Context Despite its generally warm dry climates, the Murray-Darling Basin (MDB) has a distinctive array of river and floodplain ecosystems, and these are habitats for native aquatic and riparian plant and animal species. Many of the native plant species and most of the native vertebrates and invertebrates are endemic, so are adapted to specific aspects of Australia’s climate and to the flow and water regimes of rivers and wetlands.
However since European settlement, the native flora and fauna have been boosted by alien (i.e. introduced and translocated) plant and animal species. Many of these have established in the MDB and several have become abundant and invasive, such as trout or gambusia in rivers or blackberry in upland riparian zones. Ecosystem disturbance facilitates the establishment and dispersal of alien species, making it likely that degraded conditions in rivers and riparian zones within the MDB have contributed to the success of these introduced species. Species that have established beyond their natural range and that are known or suspected to have negative effects on the natural environment or on economic returns, are considered pests, although the environmental effects are rarely well- documented. An additional effect is that the abundance of some alien species such as carp has a negative social effect for it generates in the community a perception that the health of rivers and floodplains within the MDB is poor.
Objectives, Tasks and Outputs Biological invasions are one of the top threats to riverine and floodplain ecosystems in the MDB. In recognising this, the Murray-Darling Basin Commission (MDBC) has also recognised the need for a strategic assessment to set priorities for action. This project sets the framework for this strategic assessment.
Specific tasks are: to identify current and potential pest species across the MDB; to canvas expert groups and stakeholders’ opinions; to investigate and develop a risk assessment process; to review information packages and materials; to identify priority areas for future research on control of pest species; and to identify project briefs. Outputs from this project include: a report describing the
v project, its methods, and findings relative to the tasks; a summary of state of knowledge of target pests presented as a set of profiles of a number of individual species; and a set of research briefs.
Risk Assessment Risk assessment is an essential tool for managers because of its capacity to place management decisions into an appropriate context, and by setting priorities so achieve greater efficiency and effectiveness. For example, early detection and intervention during invasions is an effective means of limiting invasive and pest species, yet new infestations are rarely targeted before the situation becomes critical, partly because of the difficulty in knowing whether such effort is justified. Understanding the ‘pest’ potential of an alien species in a given system and in a way that allows comparison with other species would help to set priorities for action. The capacity for this type of risk assessment is not currently available for aquatic and riparian species but is available for terrestrial weeds in the form of a decision support system, supported by social values and information on species ecology.
A test exercise using 22 potential pest plants from aquatic and riparian habitats in the MDB showed that this could be usefully applied to aquatic and riparian plants once modified to better describe their ecological attributes. This would be a powerful tool if coupled with knowledge of changes in species distribution, for example if linked to spatial information or modelling. At a workshop held to explore the feasibility of applying the same risk assessment procedure to fish pests it became evident that extending this to groups other than plants was probably feasible but would require some development. At present there is no risk assessment tool available for established and potential invasive fauna in the MDB. Consequently, there is an urgent need to develop a species alert list, from a generic risk assessment process to validate and manage new pest incursions. Development of such an effective risk assessment process for high-risk invaders, (e.g. Tilapia and Water Hyacinth) is an important cost-effective preventative strategy for the MDBC.
Education A fundamental first step in management of invasive species is to ensure no further introductions. Awareness and education are part of this first step, as people are strongly implicated in the introduction of new species to Australia and in extending the range of species already established. A review of existing educational material on pest flora and fauna in the MDB, covering both printed and internet-based information, found that the range of information available was fairly extensive vi but noted a lack of material linking people’s activities to introduced species or to invasion acceleration.
There is a clear need for the development and implementation of a cohesive multi-species pests education program for the MDB to address the public role in controlling pests. Consequently, a major project brief herein is a comprehensive project tackling an Invasive Species Education Program for the MDB, and key tasks and aims are described. Further improvement of education, communications and linkages between managers, researchers and stakeholders is important for more effective pest management strategies.
Canvassing Expert Opinion The experience of managers, agency staff, researchers and policy makers dealing directly with pest species and the issues arising is a valuable informal and contemporary source of knowledge. This knowledge was tapped using questionnaires because these are an efficient method of obtaining information and ideas within the constraints of the project. Pest plants and pest fauna were the subject of separate questionnaires, targeting different groups of people and asking questions appropriate for each groups of species.
For the pest fauna, the principal objective of the questionnaire was to determine what information is still required to improve management of pest species in the MDB and to determine what existing control strategies are most effective. Valuable information was received from 23 respondents (from 78 surveyed). The responses confirmed some research priorities, such as carp, and identified several new research needs. A common theme amongst the responses was recognition that our knowledge of the effects of invasive species is incomplete and for new species of high risk there are few mechanisms in place to predict, report or control their spread. This feedback was important in developing 18 new innovative research project briefs presented as the major outcome of the present document.
The questionnaire on pest plants was distributed by e-mail. A large number of species were identified as actual pests, as pests of significance and as potential pests, showing the need to work with species groups rather than species. Geographic differences in perceptions of which species were pests were detected. The use of bioregions as a means of ecological spatial analysis showed some strong geographical patterns within the Basin, especially contrasting northern v southern
vii areas, and uplands v lowlands. Management issues identified were fairly standard with little evidence of awareness of the specific conditions associated with aquatic and riverine environments. A total of 24 research projects were proposed, covering seven major themes. Only one of the seven species suggested for single-species research, lippia (Phyla canescens), was developed for inclusion in the research portfolio. However the survey contributed to the development of a number of research questions for the portfolio as well as some important supplementary research questions.
Development of species-specific management plans and on-ground control techniques will be vital for transfer of knowledge and technology between stakeholder groups. Widespread recognition of problems associated with these species (such as carp and willows) by the general public should be harnessed to gain understanding and ownership of river restoration principles. Several of the research briefs contained here are aimed at management of specific pest species. For example, there is an urgent need for broad-scale surveys to validate the distribution and impacts of particular established pest species. In addition, investigation and commitment to the emerging bio-control technologies are recommended. Initiation of the research and management briefs outlined here will represent a more coordinated and adaptive approach to management of biological invasions in the MDB.
Research Portfolio A research portfolio was developed, comprising an integrated research program of 18 research projects. These address various knowledge gaps and needs relating to immediate and more strategic needs, and were identified collectively by the project team, based on recent literature and consultation through the questionnaire. The team worked towards an biologically integrated approach so many of the research projects in the portfolio incorporate both flora and fauna issues and needs into a single brief.
Together, the briefs form an integrated program of research with each project drawing on and contributing to each other, and with outcomes addressing specific objectives within MDBC management strategies (see figure and table below). Project duration is variable, with projects that range from short-term (1-2 years) to medium (3-5 years) and even long-term (>5 years). The shorter projects target more immediate needs whilst the longer projects, some of which are staged, are more strategic and seek to strengthen our knowledge base.
viii A co-ordinator is required to ensure the research program is implemented in a cohesive manner. This person is central to the success of the research program. An additional role is to ensure positive interaction and synergy between projects. To ensure there is an effective exchange of information and overall direction of the projects, a high level of expertise is required. The co- ordinator will need a solid understanding of invasive species biology and of pest management principles, and will need to understand the theory and techniques in the research projects. An associated responsibility will be to ensure that the educational strategy is implemented and supported, whilst also contributing a ‘pest species’ perspective to other environmental management programs in the MDB.
Linkages between pest species projects providing an integrated research program.
Species Management Broadscale Management and Education
8. Willow 1. Education strategy 9. Lippia 2. Generic framework 10. Blackberry 3. Rapid response system 11. Alligatorweed PEST CO-ORDINATOR 4. Co-ordinated control programs 12. Gambusia 5. Integrated weed management 13. Carp 6. Translocation review
C
Research to fill Knowledge Gaps
14. Pest distribution 15. Ecological impacts 16. Pathogens 17. Biological control 18. Habitat rehabilitation
ix Summary of projects Project Project Title Time Scale* Scope Funding 1 An educational strategy for biological Short Term Basin-wide $300 K invasions Education 2 A generic framework for managing Short Term Basin-wide $120 K biological invasions Management 3 A rapid response system for new Short Term Basin-wide $120 K species introductions Management 4 A coordinated approach to managing Short Term Basin-wide Part A $250 K programs for controlling biological Management Part B $150 K invasions Part C $160 K 5 Towards improved water quality and Medium Term Basin-wide $120 K/y biodiversity through integrated weed Management management in riverine ecosystems 6 A review of translocated species and Short Term Basin-wide Part A $120 K their distribution Management Part B $120 K 7 Risk assessment for exotic and alien Medium Term Basin-wide Part A $120 K flora and fauna Management Part B $140 K 8 Addressing barriers and knowledge Medium to Basin-wide $235 K/y for 5 y or gaps crucial for effective willow Long Term Management longer management in south-eastern Australia & Research 9 Lippia as a problem species in the Medium Term Basin-wide $150-200 K riparian zone and on floodplains Management & Research 10 Integrated control of blackberry Part A - Short Basin-wide Part A $90 K Term Management Part B $120 K/year (5 y) Part B - Long Term 11 Integrated management of alligator Medium Term Basin-wide $300 K weed Management 12 Research and management of Short to Long Basin-wide Six projects gambusia Term Management & Research 13 Testing the effectiveness of carp Medium Term Basin-wide $300 K/y for 3 y eradication and control techniques Management 14 Determination of the distribution of Medium to Basin-wide Stage 1 $150-300 K/y alien and exotic species Long Term Management Stage 2 $100-150 K/y & Research Stage 3 $100-150 K/y 15 Assessment of ecological impacts of Medium Term Targeted $100-150 K /y/project alien and exotic species Research 16 Research and management of exotic Medium Term Basin-wide $250 K pathogens Management & Research 17 Investigation of potential biological Short to Scoping Study Part A $150-200 K control technologies for alien and Medium Term Management Part B $150-200 K exotic species & Research 18 Assessment of the effectiveness of Short Term Basin-wide $150 K habitat restoration as a method for Management controlling biological invasions & Research * - S = short (1-2 years), M = medium (3-5 years), L = long (>5 years)
x Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction
1 Introduction
1.1 Background The Murray-Darling Basin Commission's (MDBC) Riverine Issues Working Group and riverine environment staff have developed a Riverine Environment Strategic Plan (RESP) (MDBC 2000). The RESP identifies a range of key management issues which need to be addressed to achieve the goal of ecologically sustainable management for the riverine environment. These issues are ranked in relation to the urgency for action as well as the extent to which activities and actions are already being conducted or underway. These are: Integrated River Rehabilitation; Flow Management; Floodplain and Wetland Management; Water Quality Management; Riparian Zone Management; Instream Management and Pest Management.
This scoping study (project R2006) was initiated by the MDBC to address pest management issues within the RESP in relation to pest species. There are several pest or potential pest species which are widespread within the Basin and an assessment is required to determine actions and priorities for these, as well as contingency planning. Pest species of concern include both flora and fauna species in riparian and aquatic ecosystems. A key task of this project was to develop a priority list of projects that should be considered for funding by the MDBC for the future management of pest species. This builds on recommendations for two potential topics for future research projects already identified by the MDBC Riverine Issues Working Group (CRCFE 1999); An assessment of pest species across the MDB and promoting the community's role in managing pest species.
1.2 Objectives The four key objectives are: • Investigate risk assessment processes to identify priority pest species (Chapter 2) • Review educational material concerning pest species within the MDB (Chapter 3) • Identify current and potential pest species within the MDB (Chapters 4 and 5) • Identify priority areas and develop project briefs to fill knowledge gaps and research needs concerning the control and management of pest species (Chapter 7) In addition, nineteen profiles of selected pest species were developed (Chapter 6).
1.3 Definitions - What is a Pest ? The question 'What is a Pest?' encompasses three issues: • what is meant by the term 'pest'? • what is the relationship between this term and the terminology used in invasion biology? • how is a particular species assessed to meet the definition of a pest? The terminology used in this report is well-established in the scientific literature on biological invasions.
Terminology Invasion biology and pest ecology have a rich vocabulary to describe degrees of nuisance species, stages of invasion, accompanied by words of jurisdiction. This vocabulary has been used inconsistently in the past,
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 1 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction leading to some confusion in words and meaning. Although scientists are beginning to push for standardised words, and patterns of usage are beginning to develop, there is as yet no universally accepted ecological meaning attached to words such as pest, and some words are specific to certain branches of ecology: thus vocabulary and terms used in relation to nuisance species differs slightly between the fields of botany and zoology, as well as between aquatic and terrestrial ecology. While there are definitions within the literature for particular terms, there can also be significant differences in people’s perceptions of the meaning of terms. Confusion can often occur with the misuse of both words and concepts (Binggeli 1993). Some of the frequently used terms and their range of definitions are provided below.
The term 'pest' usually refers to organisms that have negative effects on human health, comfort, convenience or profits and can include both native and non-native species (Beeby 1993). Bomford (2001) defines a pest as "an animal that has, or has the potential to have, a detrimental effect on economic, social or conservation values or resources". The classification of a pest is often based on economic criteria when the damage caused by a pest species justifies the costs of a control program (Beeby 1993). Pests and weeds, an equivalent term when applied to plants (Bingelli 1993) may simply be species occurring in high numbers that are released from the mechanisms that ordinarily keep their population growth in check.
Confusion arises when the term ‘pest’ is used in a more general manner, and simply refers to a species which has been introduced. One critical distinction between native pests and non-native or native, translocated pests is that native pests have co-evolved with other species and the physical and biological constraints within the ecosystem in which they have become a pest. Species that are introduced to areas where they did not previously occur, on the other hand, represent a new, potential threat to existing species and ecological processes of the system into which they have been introduced. Because of a history of such semantic confusion, researchers are now moving to develop a standard set of useful and articulate words that will hopefully stabilise meanings.
The most recent developments in vocabulary have come from authors using stages of a biological invasion as a conceptual framework. This kind of conceptual approach has been used by botanists and zoologists, and has been adopted as a framework for the National Weeds Strategy.
Thus Williamson and Fitter (1996) provides the following definitions from the field of zoology: - Imported brought into the country, contained - Introduced found in the wild, feral (common usage), casual, released but not (yet) breeding successfully - Established with a self-sustaining population, naturalised, feral and breeding successfully, released and breeding successfully - Pest with a negative economic effect - Escaping transition from imported to introduced - Establishing transition from introduced to established - Becoming a pest transition from established to pest
Richardson et al. (2000) recognise the following sequential terms in plant invasion biology:
2 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction
Alien Taxa that in a given area are there due to the intentional or accidental introduction as a result of human activity (synonyms = exotic, non-native, non- indigenous). Casual Alien plants that may flourish or even reproduce occasionally in an area, but that do not form self-replacing populations, so rely on repeated introductions for persistence (includes waifs, transients) Naturalised Aliens that reproduce consistently and sustain populations without human intervention; they recruit freely, usually close to parent plants, but do no necessarily invade. Invasive Aliens that produce reproductive off-spring, often in large numbers and distant from parent plants Weeds Plants, not necessarily aliens, that grow where not wanted and have detectable economic and environmental effects (synonyms = pests, harmful, problem plants) Transformers A sub-set of invasive plants that change the character, condition, form or nature of ecosystems over a substantial area, relative to that ecosystem.
These authors note that approximately 50-80% of invasive species can be classed as ‘weeds’, the remaining being ‘benign invaders’. The term ‘transformer’ is useful for referring to species having a particular type of ecological impact (see below: significance of Pest Species). They consider the term pest to be imprecise.
This stage-dependent terminology provides a cascade of terms that is mirrored by a diminishing cascade in numbers, and helps to define the nature of the management problem. A staged conceptual framework, similar to the Goals and Objectives of the National Weeds Strategy (Figure 1) should be considered a useful template for an invasive species program within the Murray-Darling Basin (ARMCANZ 1999).
Figure 1 visually depicts the stages from a species being introduced to an area to potentially becoming a pest once it has established itself in an area.
General terms in common use are (taken from Oxford Dictionary): - Alien “belonging to a foreign country, introduced from another country and later naturalised “ - Exotic “originating in or characteristic of a distant foreign country”. In the context of fish management the term “exotic” sometimes refers only to captive aquarium fish species that have been imported from other countries (NSW Fisheries) but are not found outside of captivity. - Naturalised "establish so that it lives wild in a region where it is not indigenous" - Feral “in a wild state, especially after being domesticated or cultivated”. 'Feral' is a term which is often used to describe numerous terrestrial animal species, such as cats, horses and goats - Noxious “harmful, poisonous”. 'Noxious' often has a specific meaning in legislation in relation to non-native species.
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 3 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction
For plants the term 'weed' often seems to be incorporated within the general term of 'pest'. Weeds are generally considered to be plants that are either native or introduced and interfere with the objectives and requirements of people (Bingelli 1993). Many people may perceive a 'weed' as simply a plant that grows in the wrong place, and the wrong place can be defined in various ways: for example Holzer and Numata (1982) distinguish three categories of weeds according to place of impact: - Agrestal weeds of agricultural land - Ruderal weeds of waste places - Environmental weeds which invade natural vegetation.
Such spatial categories are not mutually exclusive. For example, blackberries would be considered a significant weed within all three categories where agricultural land includes pasture. The weed or pest status of a species is largely influenced by its context, and thus nuisance status of a species will change as land use changes. For example, a non-productive plant may be unimportant in pasture but could become a problem if land use changes to farm forestry. In terms of fauna, blackbirds may be unimportant or possibly beneficial in cereal cropping systems but a major pest in vineyards.
Significance of Pest Species Within Australia, and therefore also within the MDB, there are numerous examples of species that have spread with the deliberate or accidental assistance of people to areas outside their natural range. Invasion biologists have observed that while large numbers of species arrive in new areas, few survive, even less establish self-sustaining populations and only a small fraction continue to spread and expand their populations (Mack et al. 2000). Some species may be 'sleepers' that are currently in low numbers and do not currently have any detrimental effects, but which may erupt in the future under favourable conditions (Hart 2001).
The definition of a pest is largely dependent on a human judgement of whether the pest species should be there and whether it is affecting other organisms we would prefer to be in a particular environment. Further confusion regarding the term ‘pest’ arises from situations where pest species have become an accepted part of an ecosystem, particularly where their impacts are minimal or sustainable (Hart 2001). Most environments have changed dramatically and few could be considered pristine where no non-native species occur. Braysher (1993) makes the distinction between perceived pests and real pests based on whether or not impacts have been demonstrated. Management of perceived pests may primarily involve education to change attitudes, while on-ground actions are required to manage real pests.
Damage may include environmental, economic and social impacts; the importance of each will depend on community perceptions and the decisions of funding bodies. Quantifying damage may be difficult or not feasible if relevant data are unavailable. Choquenot et al. (2001) note that pest control is increasingly being considered in an economic context, where consideration is given to when investment in pest control should stop. For many species, although economic impacts could be significant, specific estimates are not available. Some estimates of the economic damage of particular terrestrial pest species such as mice have been made (e.g. Brown and Singleton 2001). In terms of environmental damage, Braysher (1993) argues that while there are methods for determining environmental costs, they are not universally accepted. It is often complicated by the difficulty in confidently assigning specific impacts entirely to a pest species, particularly in already degraded environments.
4 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction
Pest Terminology for Project R2006 The definition of ‘pest’ as used in this scoping study project is: Any species that has invaded habitats within the MDB where it does not naturally occur and that is known or suspected to be detrimental in some way, which may include environmental, economic and social impacts. As used here, and in rough agreement with definitions of Richardson et al. (2000), pest thus includes species that have come to Australia from another country as well as species that are indigenous to Australia but have been translocated beyond their natural range. Native species that are or have become pests within their natural range (such as narrow-leafed cumbungi Typha domingensis) are not considered here.
Pest management is one aspect of an integrated approach to natural resource management. In the context of the MDB, allocation of limited resources to address pest species needs to be prioritised based on current information and evidence on real or perceived impacts, a precautionary approach, and sound risk assessments.
Braysher and Saunders (2001) have developed a step-by-step guide manual to determine how best to direct resources to manage pest animal damage in an area. The following principles should be considered in assigning priority to pest species, including those that are alien or translocated species, and management areas, which incorporates points of Braysher and Saunders (2001) and Hart (2001). Setting priorities for pest species and management approaches will depend on the geographic scale in question eg. local, regional, state and basin-wide.
Priority Current and Potential Pest Species may include those: • which are known or suspected to cause significant environmental, economic or social damage • which cause ongoing damage over large areas over the long-term • which have not yet invaded the MDB but potentially represent a high risk of establishment and causing significant impacts • which currently have restricted distributions but may have a high potential for expansion
Priority Management Approaches include to direct resources to areas: • where the chance of success in control/eradication and cost/benefit are highest • where pests do not currently occur and their invasion can feasibly be prevented • where significant native species, communities and habitats occur • where control/reduction to adequate/desirable levels or eradication is feasible and desirable economically, socially, politically and environmentally.
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 5 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Introduction Figure 1: Temporal stages of an invasion
Transport
Deliberate or Accidental Arrival
Escape Deliberate or Accidental Establishment
Impacts
Real or Perceived? Environmental, Economic, Social ?
Minimal Significant
No active PEST management Targeted management and research for control and/or eradication
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2 Risk Assessments It was feasible to undertake a detailed risk assessment for invasive and weed plant species within the MDB, using an established Decision Support System (section 2.1). A multi-criteria analysis/analytical hierarchal process (AHP) weed assessment process was established for aquatic and riparian species but requires additional input from MDBC on resource values as well as more information on the present distribution of weeds in the Basin. Given the limited nature of the project, there is potential to evaluate many more riparian, riverine and aquatic weeds to assist in determining local, regional and national priorities for weed management within the MDB.
A detailed risk assessment process has yet to be established for invasive aquatic fauna within the MDB. A preliminary investigation was however undertaken which involved a brief review of potential methodology including adaptation of the methodology employed for weed species outlined below (Section 2.2).
2.1 Aquatic and Riparian Weed Risk Assessment In Australia, over 2750 plant species, including deliberate and accidental introductions and invasive native species, have been reported in the literature as weeds (CRC for Weed Management Systems 1996). Alien plant species have naturalised in Australia at an average rate of 11-12 species per year over the past 25 years. Most of these (> 80%) have escaped after deliberate, legal introduction for use in horticulture and agriculture.
In order to make informed decisions about the best way to control weeds on public and agricultural land it is necessary that the relative importance and potential impact of each weed be determined prior to the allocation of priority works or funding. It is essential that the importance of individual weeds in our environments be understood otherwise the decisions to control them cannot be correctly made. Decisions based on limited factual data and emotional reactions will almost certainly result in unnecessary expenditure of resources and damage to the environment through inappropriate use of control measures.
The three major components in predicting weed status are: 1. Assessing the plant’s invasiveness 2. Its current and potential distribution and 3. Impacts of the plant on land use and ecosystems.
The decision-making process should also include: • The value of threatened ecosystems and • The feasibility of successful control.
To date, approaches to weed risk assessment (WRA) have concentrated on those biological properties of a plant species that make it invasive. However invasiveness is only one component of WRA. In order to determine or prioritise weeds, an assessment must also take into account the impact of the weed on social, environmental and agricultural values (or resource conditions). As these values change depending on the land managers involved and the scale being considered (national, state, catchment or local), the assessment procedure must be adaptable to account for these differences.
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A risk assessment process has been developed that is a paradigm-shift in approach for it focuses on threat that a species places on certain resources. The process can work independently or utilise a GIS-based system to determine resource conditions and then the risk or threat that weeds pose to these values.
Methods This Decision Support System (DSS) is an Expert System relying on multi-criteria analysis/analytical hierarchical process (AHP) that enables complex issues to be broken down into sets of related criteria. The AHP, developed by Dr Saaty, is a method that assists with decisions about priorities using qualitative and/or quantitative information. It facilitates effective decisions on complex issues by simplifying and expediting the intuitive decision-making process.
AHP does this by organising a complex unstructured situation into its component parts, and then it arranges these parts into an hierarchical order, assigns numerical values to subjective judgements regarding the relative importance of each variable, and synthesises the judgements to determine which variables have the highest priority. AHP also provides an effective structure for group decision-making. This is generally done either based on already documented scientific information or in workshop sessions with experts.
"(AHP) enables us to make effective decisions on complex issues by simplifying and expediting our natural decision-making process. Basically the AHP is a method of breaking down a complex unstructured situation into its component parts; arranging these parts, or variables, into a hierarchical order; assigning numerical values to subjective judgements on the relative importance of each variable; and synthesising the judgements to determine which variables have the highest priority and should be acted upon to influence the outcome of the situation." (Saaty, T., (1995), Decision-making for Leaders: The Analytical Hierarchy Process for Decisions in a Complex World, RWS Publications, Pittsburgh)
Because there is a lack of specific information on land/resource value and the impact of any particular weed on social, environment and agriculture resources there is a need for a methodology to mix both qualitative and quantitative information. The DSS allows for this integration.
This Weed Risk Assessment process is the only system that allows for a visible weighting to be applied to more important criteria or resources to indicate their importance.
Nine-step approach to using AHP in Risk Assessment Table 1 provides a summary of the steps as described by Saaty (1995) and their modification for application to this case study.
“To define a complex problem and to develop sound judgements, the AHP must be progressively repeated, or reiterated, over time” (Saaty, 1995, p.23). It is the great strength of AHP, as a decision support system, that it does enable systematic development where the process can be repeated and decision-makers can both amend the hierarchy and review judgements.
In broad terms the approach to carry out the AHP is the same, although certain steps may be given special emphasis depending on the problem of interest and repetition (or iteration) is often necessary. The approach
8 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Risk Assessment moves from the general concept to the particular and more detailed elements of the system (Saaty, 1995, pp. 94 – 95). 1. Define the problem or issue, and specify the solution desired. 2. Structure the hierarchy from the overall managerial viewpoint (from the top levels to the level at which intervention to solve the problem is possible). 3. Construct a pairwise comparison matrix of the relevant contribution or impact of each element on each governing criterion in the next higher level. In this matrix, pairs of elements, or decision variables (e.g., objectives, alternatives, and actions) are compared with a criterion in the superior level. Preference is denoted by a vector of weights following an AHP scale of relative importance ranging from 1 to 9 (see Table 1, below). The matrix has one position to enter a number and another to enter its reciprocal. An element on the left is by convention examined regarding its dominance over an element at the top of the matrix. The numbers in the main diagonal are all 1s. 4. Obtain all judgements required to develop a set of matrices in Step 3. If there are many people participating, their multiple judgements can be synthesised by using a geometric mean. 5. Priorities are obtained and consistency is tested (see Step 8, below) after collecting all the pairwise comparison data and entering the reciprocals together with unit entries down the main diagonal. 6. Perform Steps 3, 4, and 5 for all levels and clusters in the hierarchy. 7. Use hierarchical composition (synthesis) to weight the vectors of priority by the weights of the criteria, and calculate the sum over all weighted priority entries corresponding to those in the next lower level and so on. The result is an overall priority vector for the lowest level of the hierarchy. If there are several outcomes, their geometric average can be taken. 8. Evaluate consistency for the entire hierarchy by multiplying each consistency index by the priority of the corresponding criterion and adding the products. The result is divided by the same type of expression using the random consistency index corresponding to the dimensions of each matrix weighted by the priorities as before. The consistency ratio should be 10 per cent or less.
And if relevant: 9. Use AHP ranking to define priority control areas, using any key data and GIS as a platform.
If the consistency ratio is greater than the chosen threshold, Saaty suggests a revision of the questions posed and re-evaluation of the comparisons. If this fails to improve consistency, it is likely that the problem or issue has not been accurately structured; that is, similar elements have not been grouped under a meaningful criterion. A return to Step 2 is then required, although only the problematic part of the hierarchy may need revision.
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Table 1: AHP steps, as described by Saaty SAATY MDBC STUDY HIERARCHY 1 Define the problem and specify 1 Definition of the issue(s) – problems and/or the solution desired opportunities 2 Structure the hierarchy 2 Formation of “core” technical support group 3 Identification of the focus 4 Constructing the hierarchy 5 Where necessary, break down the primary criteria into secondary / tertiary sub criteria 6 Group agreement on the decision tree WEIGHTING 3 Construct a pair-wise 7 Weight the criteria - using the Catchment Decision comparison matrix Assistant©(CDA) software to generate the weighting of the criteria at each level using a process of pair-wise 4 Obtain all judgements required comparisons. to develop the set of matrices The CDA will check for consistency of the evaluation of 5 Test consistency the weighting and, if inconsistent, will give the option of reiteration of this step. Perform 3 – 5 for all levels and 6 clusters in the hierarchy 8 Develop and apply the intensity ratings for each of the Use hierarchical composition to specified regionally controlled weeds. weight the vectors of priorities 7 by the weights of the criteria, CDA generates an Excel spreadsheet into which users and take the sum over all can enter the intensity ratings against each lowest level weighted priority entries criteria. The spreadsheet automatically calculates corresponding to those in the weighted score and final AHP rankings. next lower level and so on.
Evaluate the consistency of the entire hierarchy.
The key benefits of using this type of Decision Support System are: • It takes advantage of existing information by systematically integrating it into a system that allows a wide range of users to interpret the data using a set of tools developed by experts. • It captures the expertise of specialists and makes this expertise available across a wide range of decision- making contexts. • It provides an explicit method for integrating ecological, social and economic criteria into the decision- making process. • It can provide a set of "best practice" decision-making tools to planners and managers. • It provides a mechanism for identifying information shortfalls. • It enables a qualitative analysis of the suitability of data and its relevance to the decision-making process.
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• It provides a framework for developing sophisticated benchmarks, including identifying the necessary tradeoffs between competing value systems. • It is easily up-dated as research fills knowledge gaps.
Weed Risk Assessment utilising the Analytical Hierarchal Process The species that are of highest risk are those that have the potential to greatly impact on valued resources. So to determine the priority for invasive species for a given area, it is necessary to determine the:
Impact: Present vs Potential Impact; How much of a resource could the species threaten. The level of impact of a species on a resource can be determined through scientific input, found either from references, resources, and experiments or through expert knowledge. Impact: How fast could the species spread or how fast might the impact occur. The rate of spread of a species can be determined through modelling based on dispersal, reproductive and mortality rates. Impact: What resources are being threatened; by how much and what are the value of these resources. However the value of resources can only be determined by getting the managers responsible for those resources to prioritise or value them (in relation to each other). This process can be accomplished through workshops using the AHP - DSS to rank the social, environmental and agricultural resources of the region.
So in summary the information to enable threats to be assessed are: • The present or future species that could threaten the region. (Species list) • Information about the biology of the species and the ability to estimate its potential rate of spread. • The amount of impact that a species could have on social, agricultural and environmental resources. • The values that the land managers assign to those resources (usually achieved through a workshop)
There are three main items that determine the importance of an invasive species: 1. How invasive is the species, i.e. how fast can the species spread, generally this relates to the intrinsic biological features of the species (i.e. dispersal, reproductive and competitive rate) 2. What is the present and potential extent of the species 3. And most importantly what social, agricultural and environmental impacts does the species have and how much do we value the things that are impacted.
The relevant criteria for assessing the invasive potential and the impacts of aquatic and riparian weeds were developed with the assistance of New Zealand's aquatic weed expert, Paul Champion of Hamilton labs of NIWA, and derived from the New Zealand's Aquatic Weed Prioritisation system (Figure 2).
Two examples are given: The hierarchy for aquatic weeds (Figure 2) and a hierarchy for non-established riparian and aquatic plants (Figure 3).
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Figure 2: Hierarchy for determining aquatic (and riparian) weed risk
Aquatic Weed Priority
Groups
Social, Agricultural and Invasiveness Present and Potential Distribution Environmental impacts
Criteria
Versatility Present and Potential Social (Obstruction) Temperature tolerance Recreational Salt tolerance • Habitat preference Access Habitat range Power generation Water/substrate type • Climatic preference Flood control Clarity of water required Aesthetic Competitive Ability • Area Human health Within lifeforms Environmental Between lifeforms Reduction in biodiversity Propagule Dispersal Water quality Natural agents Physical processes Accidental human spread Agricultural Deliberate human spread Irrigation Spread within catchment Pre or post production Seeding Ability Resistance to Management Quantity of seeds Ease of implementation Persistance of seeds Recognition of problem Cloning Ability Scope of control methods Maturation Rate Acceptability of methods Effectiveness of control Duration of control
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Figure 3: Full aquatic weed hierarchy
NO Does the plant have the potential to invade this region, i.e. is it Proceed no further, plant is not a weed climatically suitable. risk
YES Proceed with risk assessment, but include "History as a weed elsewhere" with appropriate weights: NO Subgroup Has this plant naturalised in the country. Invasiveness Impact YES Prior History as a weed.
Naturalised Aquatic Weed Priority Assessment Invasiveness Versatility Temperature tolerance or Tolerance to environmental temperature fluctuation Tolerance to salinity fluctuations Nutrient requirement of water or substrate Habitat tolerance of depth range Tolerance of fluctuations in turbidity Competitive ability Within Lifeforms Between lifeforms Propagule Production and Dispersal- #propagules and frequency Propagule Dispersal Natural Human (accidental or deliberate) Propagule Production Seeding Ability Quantity of seed Persistence Cloning Ability Impact Degree of Obstruction Recreational Access to waterbody Power generation Irrigation or flood control Aesthetic Damage to Natural Ecosystems Negative effects on biodiversity Decrease water quality Negatively impact on physical processes Resistance to Management Ease of implementation Recognition of problem Scope of available control methods Effectiveness of control
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Application of AHP and Results Because of the large number of introduced species identified from the questionnaire survey and literature, WRA utilised only a sub-sample of weeds. The twenty-two species used (Table 2) cover a range of habitats (riparian, riverine, and aquatic), a range of growth-forms (woody and non-woody species, and climbers) and life-cycles (annuals, perennials) and impact on a range of values (social, environmental and agricultural) and are generally quite widespread. Thus whilst not being formally representative of the Basin, they do at least cover its diversity. These 22 species were used because they were among the first set of replies to the Pest Plant Questionnaire (Section 5) and because the necessary biological and ecologist species information was largely available. Species such as lippia Phyla canescens could not be included because the information needed was not available.
The results below, therefore, demonstrate the application of AHP WRA to the Basin but are not representative of it. A revised assessment based on common or significant pest plants, as identified by stakeholders or other process, could be undertaken as part of Research project 7 (Section 7.4.7).
Ranking of 22 weeds of MDB using the weighted Analytical Hierarchical Process. Results are shown in Figures 4 to 5; and in Tables 2 to 5.
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Table 2: Invasiveness assessment scores for 22 sample species in the MDB Questions Scientific name 123456789101112131415 Alternanthera philoxeroides MLHHHHHHLHLHLLHM Cabomba caroliniana MHLMHHHLMMHHLLHH Carthamnus lanatus MLLLHHMHLMLMMLHLM Cuscuta campestris ML L M H H M H M M L M H M H M Datura ferox MLLMMHHHLMMMHHLM Datura stramonium MLLMMHHHLMMMHHLM Echium plantagineum H LMHHHHMMLMHMLM Egeria densa MHLMH L HHMMHML L HM Eichhornia crassipes MLLMHHHHHMHHHHHH Foeniculum vulgare ML L M H H H H M M H M H M H L Ligustrum lucidum ML L M H L MH H H L H M H M L L Ligustrum sinese ML L M H L MH H H L H M H M H L Lycium ferocissimum MHLMHHMHHMHMHML L Opuntia aurantiaca MLMH L HH LMHML L LM Parthenium hysterophorus L LMHHHH LMLMHMLM Rubus fruticosus MHLMHHHHHMLMHMH L Sagittaria graminea MLLMHMHHMMHMHMHM Salix babylonica MLLHHHHHHMHMHMH L Salvinia molesta MLLMHHHHLMHHLLHH Silybum marianum HLMMHHHMMLMHMLM Xanthium occidentale MLHMHLHHLMLMHMLM Xanthium spinosum MLLMHLHHLMLMMHMLM
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Table 3: Impact assessment scores for the 22 sample species in the MDB Questions Scientific name 1 2 3 4 5 6 7 8 9 10111213141516171819 Alternanthera philoxeroides MML HMHMHMLMLMMMHHHMH Cabomba caroliniana H L L H M MH M H H H L H L M MH MH L M L Carthamnus lanatus LMLLMMLLLLLLLMLLLMH Cuscuta campestris LLLLMMLLLLLHLMLLHLH Datura ferox LMLLMMLLMLLLLMLLMHHH Datura stramonium LMLLMMLLMLLLLMLLMHHH Echium plantagineum LLLLMHLLLLLLLMLLMHMH Egeria densa M L H H M H L M H H L H L M MH MH ML M L Eichhornia crassipes HLHHMHMLML L LMHHHMLML Foeniculum vulgare LMLLMMHLLLLLLLMLLHLL Ligustrum lucidum LLLLMHLLMLLHMHLLLMH Ligustrum sinese LLLLMHLLMLLHMHLLLMH Lycium ferocissimum LHLLMMHLLMLLLLMLLLMH Opuntia aurantiaca LHLLMMLLMLLLLMLLLMH Parthenium hysterophorus LLLLMMLLLLLLMMLLMHMH Rubus fruticosus MM L L MH L MM L L L MM L L HMH Sagittaria graminea LMLMMHLMML L L LMMHLMHLH Salix babylonica ML LMMHMHL L L H LMHMHHL H Salvinia molesta MMMHMHMMM L L L L H H HMLMH Silybum marianum LMLLMMHLLMLLLLMLLMHMH Xanthium occidentale MHLLMMHLLMLLLMMLLMHMH Xanthium spinosum LLLLMMLLLLLLLMLLMHMH
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Weed Assessment of MDRC Weeds (unweighted)
Xanthium spinosum Xanthium occidentale Silybum marianum Salvinia molesta Salix babylonica Sagittaria graminea Rubus fruticosus Parthenium hysterophorus Opuntia aurantiaca Lycium ferocissimum Ligustrum sinese Ligustrum lucidum Foeniculum vulgare Eichornia crassipes Egeria densa Echium plantagineum Datura stramonium Datura ferox Cuscuta campestris Carthamnus lanatus Cabomba caroliniana 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 Alternanthera philoxeroides Weed Assessment Score
Figure 4: Weed assessment involving unweighted criteria
Weed Assessment of MDRC Weeds (Weighted) Xanthium spinosum Xanthium occidentale Silybum marianum Salvinia molesta Salix babylonica Sagittaria graminea Rubus fruticosus Parthenium hysterophorus Opuntia aurantiaca Lycium ferocissimum Ligustrum sinese Ligustrum lucidum Foeniculum vulgare Eichornia crassipes Egeria densa Echium plantagineum Datura stramonium Datura ferox Cuscuta campestris
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 Weed assessment score
Figure 5: Weed assessment involving weighted criteria
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Table 4: Ranking weeds from highest to lower priority Scientific Name Common Name Ranking Score Eichhornia crassipes Water Hyacinth 1 0.80 Egeria densa Leafy Elodea 2 0.70 Salvinia molesta Salvinia 3 0.65 Alternanthera philoxeroides Alligator weed 4 0.63 Salix babylonica Weeping willow 5 0.62 Rubus fruticosus Blackberry 6 0.56 Cabomba caroliniana Cabomba 7 0.55 Sagittaria graminea Arrowhead 8 0.50 Ligustrum sinese Chinese Privet 9 0.49 Ligustrum lucidum Large Leaf Privet 10 0.46 Echium plantagineum Paterson's curse 11 0.46 Silybum marianum Variegated Thistle 12 0.38 Lycium ferocissimum African boxthorn 13 0.38 Xanthium occidentale Noogoora Burr 14 0.37 Foeniculum vulgare Fennel 15 0.37 Datura ferox Fierce thornapple 16 0.30 Datura stramonium Common Thornapple 16 0.30 Cuscuta campestris Golden dodder 18 0.30 Parthenium hysterophorus Parthenium weed 19 0.29 Opuntia aurantiaca Prickly Pear 20 0.29 Xanthium spinosum Bathurst Burr 21 0.27 Carthamnus lanatus Saffron Thistle 22 0.24
Grouping weeds Weeds can be grouped according to their scores. The maximum score possible is 1. Scores greater than 0.7 indicate a very high potential to have a significant impact on MDB's social, environmental and agricultural values. Scores below 0.3 indicate a much reduced capacity impact on these values.
Although this assessment procedure can differentiate accurately to 2 significant places, the objective is not to discriminate between two closely scored species. This is because the scoring system already groups the plant's attributes into categories (e.g. produces between 1000 and 2000 propagules or greater than 2000 propagules). Thus the overall ranking of the plants has to be in a similar grouping system (e.g. High, Medium High, Medium Low, Low weed potential).
Breaks in the distribution of scores can be used to differentiate between plants that are very high priority species, those that are of high priority, and those that are lower priority. Scores for the 22 species (Table 4) show clear breaks between 0.61 / 0.56 and 0.46 / 0.38, thus the 22-species sample can be broken in 3 groups as shown in Table 5.
Of the 22 species assessed, five are very high priority and six are high priority.
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Table 5: The 22 sample species grouped according to their invasive and impact potential
Very High Priority High Priority Lower Priority Eichhornia crassipes Rubus fruticosus Silybum marianum Egeria densa Cabomba caroliniana Lycium ferocissimum Salvinia molesta Sagittaria graminea Xanthium occidentale Alternanthera philoxeroides Ligustrum sinese Foeniculum vulgare Salix babylonica Ligustrum lucidum Datura ferox Echium plantagineum Datura stramonium Cuscuta campestris Parthenium hysterophorus Opuntia aurantiaca Xanthium spinosum Carthamnus lanatus
Discussion The risk assessment of this sample of 22 weeds indicated that five species are of very high priority. Four of these are aquatic weeds (water hyacinth, alligator weed, leafy elodea and salvinia), and two in the high priority category were also aquatics (cabomba and arrrowhead); there were no aquatic plants in the lower priority class which instead was characterised by short-lived species, often with prickles or thorns, and mostly in the family Asteraceae.
The prevalence of aquatic species in the top two ranks is a reflection that the criteria, intensity ratings and the weightings (Appendix 2: Invasive and Impact Criteria and Intensity Ratings for Aquatic and Riparian weeds) emphasise the impact on aquatic systems in preference to riparian or riverine systems. The presence of the willow (S. babylonica) within the very high priority group indicates that this impacts strongly on the aquatic values of the river system.
Note that willows, cabomba, alligator weed, salvinia, and blackberry are all Weeds of National Significance (WONS) so were expected to rank highly in this assessment. Parthenium weed is also a WONS, but does not rate so highly in this WRA because, although very invasive, it affects dryland pasture rather than aquatic or riparian ecosystems.
Comparing the non-weighted and weighted assessments (Tables 3 and 4) shows that weighting did not greatly change the overall ranking but did allow greater discrimination between species in the middle order. For example in the unweighted assessment, there was virtually no difference between seven species (Xanthium occidentale, Silybum marianum, Ligustrum lucidum, Foeniculum vulgare, Echium plantagineum, Datura stramonium, D. ferox and Cuscuta campestris) whereas the weighted assessment stretched these out and so facilitated allocating these to groups. The weighting process also ensures that species that impact highly on high value resources are again highlighted.
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New and emerging weeds and potential distribution A powerful weapon against weed invasions is early intervention. Early intervention can significantly reduce the social cost of weed invasions (Figure 6) and the chance of eradication (Figure 7). In the assessment process this is determined by comparing the present and potential distribution.
All too often priority is given to projects where a clear weed problem already exists. Areas where early intervention is urgently required generally go unfunded or are given a lower priority until weed infestations become critical, by which time action is often too late.
A much higher priority should be given to early intervention at all levels. Formal protocols for early intervention should be developed and implemented as a matter of urgency. Such protocols must; • facilitate early detection of a potential problem, • provide for the identification and reporting of a potential problem, and • ensure action against a potential problem, including the availability of resources.
Although the AHP WRA process has the potential to do so, it was not used here to evaluate or discriminate between established and new or emerging weeds. Replies from the questionnaire did not have sufficient resolution regarding species X bio-region (Appendix 2) across the Murray-Darling Basin to accurately determine present distribution of pest plants.
Having confirmed a species as highly invasive and having serious local impact, the next step is to determine its potential distribution. A wider distribution of a weed means a greater total impact. For terrestrial plants, the three most important factors influencing weed distribution are climate, soil properties and land use. Climate limits distribution according to how seasonal temperature and moisture stresses affect the weeds life cycle.
Knowledge of potential distribution is essential when comparing the threats posed by weed species (Pannetta and Dodd 1987). The greater the potential distribution of a weed species, the greater the potential impact and management costs. Knowledge of potential distribution is also important for devising management programs. Thus for regions and habitats where a species is expected to expand, landholders can be alerted of the risk of invasion and measures can be enforced to prevent the introduction of weed propagules. Conversely, low priority can be given to areas where a species is not expected to persist, or is unlikely to be of major economic importance (Pannetta and Dodd 1995).
Once naturalised within a region, whether a species remains an insignificant adventive or realises its biological potential as a weed is largely dependent on the absence of damaging natural enemies and suitable habitat which, for terrestrial plants, means the presence of suitable soils, climate, land use and management practices (Pannetta and Mitchell 1991). The potential distribution is determined by a species environmental tolerances (climate, soil type etc.) and the ecosystem/ landuse that it invades.
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Figure 6: Total social cost of plant invasion in relation to timing of intervention: early versus late Costs of early expenditure (area A) and the resulting benefit (area B). (Adapted from Hobbs and Humphries 1995)
Late
B
A
Early Intervention Time
Figure 7: Theoretical increase in relative abundance over time by an invading plant species and chance of eradication After Groves (1992) and Hobbs (1991).
Chance of eradication
Pest Abundance
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Potential distribution can be predicted using spatial information of climate, landuse and vegetation mapping. The climatic tolerances and requirements of a plant species can be established from international and Australian scientific literature, as can other relevant environmental information. Predictive mapping is more problematic for aquatic and riparian species as their distribution is not so strongly linked to regional climate types (in sense of rainfall and temperature). Moreover, and especially in hot, dry climates, rivers and floodplains are distinct spots of climate within a regional type of climate.
An alternative to conventional GIS modelling and its spatial representation may be to use landscape patches with similar environment and ecology, ie eco-regions or bio-regions. The national system currently in use in Australia is the Interim Biogeographic Regionalisation for Australia (IBRA). In 1999, IBRA Version 5 was developed, comprising 85 bio-regions, each comprising a homogeneous set of environmental attributes, expected to be drivers of species occurrence and their interaction with the physical environment. These IBRA units are a framework for conservation planning and sustainable resource management within a bio- regional context. Thirteen bio-regions occur in the Murray-Darling Basin (Figure 8).
Overlaying species environmental requirements and tolerances onto bio-regions (i.e. habitat rather than climate mapping) may prove to be effective as a broad-scale first approximation for determining the potential distribution of a pest species across a large area such as the MDB. The relative importance of new or recently-established plants could be established by comparing present with potential distribution. If expressed numerically, eg as a ratio, this could be used in the assessment procedure, as a weighting factor; for example a species with a low present but high potential distribution would be highly weighted as a threat.
Management Considerations Considering the difficulty in predicting the invasive potential of introduced species (especially species not introduced elsewhere in the world), it is essential to look at the reasons and justifications for introducing plant species. Hughes (1994) has extensively discussed the pros and cons of species introductions and provided guidelines for the introduction or non-introduction of non-native species. In the case of a species that is the only means to satisfactorily fulfil a long-term need, Hughes (1994) suggested that it is essential to ensure its invasive potential will be as limited as possible. Procedures to reduce the risk of introducing a potentially invasive species should include extensive information searches prior to the proposed introduction and the establishment of limited trial plantings.
All introductions of non-indigenous plant species should be screened with great care in a process that considered the status in the native range and at other points of introduction. The following points identified by Binggeli et al. (1998), require particular attention and should rapidly provide a clear indication to the introduced species invasive potential.
a. Has the species or a related species has been reported as invasive elsewhere?
b. How similar is the site of the proposed introduction to that of the species in its native and invaded regions? This includes comparisons of soil, climate, disturbance (both in terms of intensity and periodicity including that of fire, wind, flood) and human disturbance. Conditions favouring or limiting the species spread should be identified.
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Figure 8: Interim Biogeographical Regional Units for the MDB
c. Knowledge of the species reproductive biology is important and in particular that of seed production, seed longevity, and dispersal ability.
d. Susceptibility of young individuals to grazing (e.g. whether the plant is thorny or not),
e. Assessment of practical and effective methods of control in the case of weediness problems. The economics of control must be carefully considered.
If the above points indicate that the proposed species has no invasive potential an introduction may be considered. On the other hand if the proposed species exhibits invasive tendencies strong justifications will have to be made for its introduction.
The following points are essential in detecting the early stages in an invasion:
1. Awareness that the species is a problem in another region where climatic and environmental factors are similar,
2. First-hand knowledge in identifying and recognising the species in the wild is essential, and
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3. Active governmental or voluntary organisation in the field of plant invasions is necessary to provide background response.
Conclusions Of the 22 weeds assessed, five were deemed to be of very high priority to the MDB system. The aquatic and riparian AHP weed assessment process is established but requires additional input from MDBC on resource values as well as more information on the present distribution of weeds in the Basin. There is a need to evaluate many more riparian, riverine and aquatic weeds to assist in determining, local, regional and national priorities for weed management within the MDB system. Preventing new weeds escaping into the Basin, early detection and rapid response on priority weeds is the most cost effective strategy and hence a high priority for the MDBC.
2.2 Risk Assessment for Pest Fauna Over the past 200 years, the native fauna within the MDB have been augmented by the introduction of exotic and alien aquatic species, many of which have formed self-sustaining populations. Successful pest management is dependent on making effective decisions about complex problems while making the best use of resources. Prioritisation is needed for research and management of pest species given the limited funding available. Applying risk assessment processes can assist in determining which species are likely to be of greatest concern and which should be the focus of management action.
Risk assessments involve identifying harmful events and then estimating the likelihood of these events occurring and the probable consequences if they do (Bomford 2001). Risk assessments can involve the development of models where particular key parameters are altered to generate predicted outcomes. Given ecological risk assessments use available information, Hickling (2001) cautions that placing emphasis on probabilities in risk assessments can conceal the uncertainty and ignorance which underlies pest management strategies. Insufficient data may limit the degree of confidence with which harmful events can be estimated.
A variety of risk assessment techniques has been used to simulate and predict future trends for invasive flora and fauna in Australia. These assessments consider aspects such as environmental tolerance, impacts, dispersal vectors, and competitive ability of the invasive species. Duncan et al. (2001) found climatic suitability was a significant predictor of introduction success and subsequent geographical range size for introduced birds in Australia. Bomford (2001) has developed a quantitative risk assessment model for the import and keeping of exotic vertebrates in Australia. This has involved an analysis of past successful and unsuccessful introductions of mammals and birds into Australia, including consideration of information from literature reviews of overseas introductions.
No comprehensive risk assessment process has yet been developed for introduced fish species in Australia. A retrospective methodology was recently trialed to assess the invasion of carp in Australia (J. Koehn unpubl.). The process involved consideration of general biological risk assessment frameworks as well as consideration of the species' profile, its overseas range, invasion and establishment success, a comparison with species in the fish communities it will invade, climate matching and habitat availability, dispersal mechanisms and pathways, environmental conditions and trends, limiting factors, surrounding phases of
24 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Risk Assessment establishment and its ability to case impacts including habitat changes. Koehn (unpubl.) concluded that the methodology could be applied relatively easily and rapidly to other fish species.
Risk Assessment Methods for Pest Fish While it is not always possible to undertake quantified risk analyses, in most cases there is no consideration of the risks associated with invasive species. Thus there is no predictive capability to foresee invasions, trends or potential impacts; predictive power for fish invasions is essential for risk management and native fish recovery (Townsend and Winterbourn 1992). The use of risk assessment methodology for a number of taxonomic groups is increasing in Australia and there is potential for these to be adapted for fish, and to other aquatic vertebrate pest species such as turtles, snakes. For example, the use of a complex Decision Support System by means of a multi criteria/analytical hierarchal process (see above) for weed species demonstrates the potential value of similar systems for fish.
There is a clear need to develop a consistent, generally agreed methodology to assess the potential and real threats associated with pest fauna species within the MDB. Research is required to compare the range of presently available risk assessment methodologies. More importantly research and development is needed to tailor a new approach for pest fauna in the MDB (see Project Brief 7, section 7.4.7). To address this deficiency the project team, as part of the present project, conducted a preliminary risk analysis workshop for aquatic fauna. The aim was to investigate applying a modified version of the KTRI Decision Support System for weed species to pest fish species.
Workshop to Trial AHP for fish species A one-day workshop was held at Arthur Rylah Institute (ARI) in May 2001, and was facilitated by Dr John Weiss of Keith Turnbull Research Institute. Participants were fish and invertebrate biologists from ARI and one fisheries scientist from NSW Fisheries. As with pest plants, the process was designed to make informed decisions for managing aquatic pest fauna by assessing the potential impact of each species. Life history adaptability was seen as a key trait to invasive success for pest fish species (Rosecchi et al. 2001). Although factual data was scarce for some decisions the discussions involved preliminary consideration of possible criteria, intensity ratings and weightings for particular parameters and values. The three major components were:
1. Assessing the species invasiveness 2. Current and potential distribution and 3. Impacts on native fauna, aquatic systems and human values
A hierarchy (Figure 9) was developed, structured along a pairwise matrix for comparison using each relevant impact or life history trait similar to that used for the weed assessment (Section 2.1). Within each sub- heading a greater level of detail has been documented for the paired comparison and weightings. These decisions are not presented here but three examples are presented below. Firstly under “Survivorship” are the sub-categories of a) grows fast in size, b) cryptic, c) unpalatable, d) spiny. Secondly under the “Physiological competitive ability” are sub-categories a) disease resistance, b) genetic fitness, c) tolerance of environmental stress (aestivation). Lastly under the “Behavioural Competitive Ability” category are a) behavioural adaptability (learning), b) competitive ability (territorial, aggressiveness), c) diet (specific vs general).
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Information needed to enable threat assessment can be summarised as: 1. What are the invasive attributes of the species (i.e. are the fish migratory, do they lay eggs which drift, are there a variety of vectors for human dispersal, is there high survivorship). 2. What is the present and potential extent of the species (i.e. are the fish resilient to a range of environmental conditions, are they adaptable, what is their fecundity, do they require certain conditions for spawning). 3. What social, agricultural and environmental impacts does the species have.
Conclusions During development of the initial hierarchy it became apparent that the development of a suitable risk assessment methodology would require further research and collation of expert opinions. The assessment process appeared to have high potential, but there was some difficulty evaluating new and emerging pest species without data. Furthermore, the weightings need to be further validated through expert workshops and field trials. However, it is likely that there will be an ongoing problem of insufficient information, either in the survey replies or literature for the whole MDB to accurately determine the present distribution of pest fish species. It is desirable that pest species within the MDB (and those which may be introduced) can be objectively ranked for remedial action and resource allocation. Preventing new pest fish escaping into the Basin, early detection and rapid response on priority fauna is the most cost effective strategy and hence a high priority for developing the AHP process.
A research project targeting the development of appropriate methods for risk assessment for pest fauna within the MDB is outlined in Project Brief 7 (see Section 7.4.7 Outline and summary of projects).
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Figure 9: Hierarchy for determining pest fish risk
Pest Fish Priority
Groups
Social, Agricultural and Invasiveness Present and Potential Distribution Environmental impacts
Criteria
Present and Potential Social (Obstruction) Recreational Competitive ability Access • Habitat preference Physiological competitive ability Aesthetic Behavioural competitive ability Human health • Climatic preference Dispersal Ability Environmental Migratory Reduction in biodiversity • Ability to negotiate physical Area Water quality barriers Physical processes Larval dispersal Egg dispersal Agricultural Human vectors Irrigation Pre or post production Survivorship Resistance to predation Resistance to Management Parental care Ease of implementation Length of larval period Recognition of problem Type of offspring Scope of control methods Acceptability of methods Environmental Adaptability Effectiveness of control Habitat tolerance Duration of control High tolerance to environmental fluctuation Reproductive periods Sexual dimorphism
Post Reproductive Output Spawning periodicity Fecundity Age at first maturity Reproductive longevity
Spawning Requirements Habitat/substrate selectivity Spawning cues/requirements
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3 Review of Educational Material
3.1 Methods A key component of this project has been to undertake a review of existing educational material on pest flora and fauna species within the MDB. The need for an educational program has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). The MDBC required a review of educational material already available in a format for a range of end users. An understanding of the educational material which already exists is an important first step in determining what additional types of material will be required in the future.
This review is limited given the scope of the project. However, we believe it provides an effective preliminary overview of available educational material, including components which are effective, where there are inconsistencies and clear gaps in information, as well as indications of what is required for the future. The review involved scrutiny of State and Federal government websites, as well as other websites which are related to varying degrees to the aquatic environment including interest, community, scientific and research organisations. This search was not exhaustive and there may be a range of other sites which required investigation in a more comprehensive review. Limited information is provided concerning weed species, given that extensive reviews of resources, such as The Weed Navigator Resource Guide (CRC Weed Management Systems 1998), have already been prepared. Information is separated into the four States within the MDB as well as more general and national resources. While there may be a range of materials which have been developed by other States that potentially have a broader applicability, these have not been included in this review.
The review also considered the comments received in response to the questionnaire on pest fauna sent to a range of relevant organisations as part of this project (Section 4).
Answers to the questionnaire on pest plants (Section 5) revealed that respondents involved in pest plant management relied on a diversity of printed reference material, and apparently rarely referred to the Web for information (although used it to receive and reply to the Questionnaire). As pointed out below (Section 5.3 Research: Information and Education), the characteristics and preferences of the target audience need to be clarified before investing in a large-scale education or information dissemination program.
3.2 Results/Outputs
QUEENSLAND
Department of Primary Industries (DPI), Queensland • Specific educational material on carp and tilapia is available including printed brochures and full colour posters with distribution maps, photos, information and contact phone numbers, including a ‘Fishwatch Hotline’ to report illegal fishing activities.
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• Advisory fact sheets are available on the DPI website (under DPI notes) covering noxious and non- indigenous fish in Queensland e.g. carp and guppies, with species line drawings and FAQ’s. • ‘Ornamental Fish Can Become Monumental Pests’ is a full colour poster with accompanying brochure providing information on non-indigenous and noxious fish in Queensland. • ‘EDFISH: The wetlands education program’ is available on the DPI website. This is an education module available to target community groups and for school teaching on noxious and non-indigenous fish and includes general information, relevant legislation as well as references. There is also a freshwater habitat module available. • Two full colour posters on the native freshwater fish of Queensland are part of the EDFISH 2000 campaign. Although fish included in the poster are listed as suitable for angling and/or aquarium species, information on distribution and ecology is also provided. A fisheries habitats poster is also available listing various types of habitats e.g. riffles, lagoons etc. with definitions and descriptions. • ‘Aquatic Invaders – Exotic pest fish’ is an education module developed by the DPI for teaching upper primary and lower secondary school levels. The module includes teacher and student resource sheets, puzzles and activities. • ‘Fishweb’ site www.dpi.qld.gov.au/fishweb/on noxious and non-indigenous fish includes a list of declared noxious fish in Queensland with specific information on some species such as carp, mosquito fish, and cichlids. The site also includes links to Queensland Fisheries News (QFN) with downloadable PDF files.
Department of Natural Resources and Mines • The website has a number of PDF fact sheets available on rivers, wetlands, riparian vegetation health assessment and exotic aquatic plant species. Most of the information available relates to aquatic plant species and includes ‘Weedbuster Week’, which was started in Queensland in 1995 and is now a national program. Weedbuster Activity Kits designed for teachers to use in the classroom with Years 5-7 are available. In addition to these there are a number of teaching and learning resources on catchments, biodiversity and vegetation available in modules which can be downloaded or ordered as hard copies. • There are downloadable NRM facts sheets which primarily relate to terrestrial pest flora and fauna, although there are some for aquatic species such as Cabomba, Alligator weed and Water hyacinth. • There are educational modules for junior and secondary schools for a range of issues including pest management.
Queensland Museum • The fish section (Ichthyology) maintains a collection of about freshwater fish with an associated database that includes valuable historical data on the distribution of fishes throughout Queensland. The section also provides specimen identification and general fish information advisory service to the public, the scientific community and private consultants.
General • The Queensland DPI in association with Australian Geographic and the Barron River Catchment Management Association have produced a colour poster on catchment care for the future. The poster depicts ‘a well-managed stream’ and ‘a stream in trouble’, outlining functions, processes and
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management issues relevant to the health of streams such as the importance of riparian vegetation, instream habitat and stream flow.
VICTORIA
Arthur Rylah Institute, Department of Natural Resources and Environment (DNRE) • A poster and seven information sheets have been produced on projects funded by Agriculture Fisheries and Forestry Australia (AFFA) through the Natural Heritage Trust Murray-Darling 2001 Fish Rehab program. There is a range of material which addresses key threatening processes relevant to native species such as desnagging, cold water pollution, barriers to movement and genetic issues, as well as specific issues concerning pest species such as carp and more general issues such as restoration of rivers for native species: • “Carp Check Points”. Point-source Management of Carp (info sheet) • “Bringing Native Fish Back to the Rivers” (poster) • "CodWatch" newsletter that gives information on projects relating to river management and fisheries issues. The newsletter is sent to a wide variety of interested groups e.g. angling groups, naturalists clubs, and has a circulation list of about 15 000.
Fisheries Victoria (DNRE) • “Get Hooked…It’s fun to fish. National Junior Fishing Codes Education Kit” has been produced by Fisheries Victoria and contains information and activities for Grades 3-6 (CSF levels 3 & 4) with examples below. Learning outcomes are linked to the National Code of Practice for recreational fishing and to the National Curriculum for Science and SOSE. Level 3 (Grade 3 & 4) contains
• Take only what you need (catch limits, food chains, harvesting of bait, protected species) • You’re the solution to water pollution Level 4 (Grade 5 & 6) • Throw the little ones back (juvenile fish, habitat, ways to return fish safely) • Quality catchments equal quality fish (catchments, fish friendly waters, eutrophication)
Department of Natural Resources and Environment A number of education resources are available in hard copy and as PDF files that relate to wetlands and catchments (see below). These resources have the potential to be developed with pest species issues included. • Wetlands Resource Materials for Teachers is available on the NRE website and in hardcopy. There are also a set of slides and other material to accompany this resource. • Catchment Education Resource Book is available as a publication for teachers and is based on the themes of land, water, soil and pests. • Victoria’s Biodiversity Education Resource Book (1 & 2).
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SOUTH AUSTRALIA
Primary Industries and Resources South Australia (PIRSA) • PIRSA offers free education services to schools and community groups with the aide of a travelling education officer. While most topics focus on geological issues these could be adapted for aquatic issues. • There seems to be only very limited information within the PIRSA website or the associated SARDI (South Australian Research and Development Institute) about aquatic invasive species, either flora or fauna.
Murray Users (SA) • The Water Resources Group, Department of Environment and Natural Resources have set up this website in conjunction with the CARE (Community Action for Rural Environment). The site contains fact sheets on introduced and native fish species, macroinvertebrates and other issues relating to the River Murray. Links to other organisations such as Watercare and various catchment management boards are detailed. The links page also contains a dedicated section on educational resources for teachers including fact sheets, teaching modules, student resources, which focus on water and catchment issues and are applicable to primary and secondary schools as well as the broader community.
Upper River Torrens Landcare Group Inc. • Colour brochures on the native and exotic freshwater fishes of the Mount Lofty Ranges have been produced with colour photographs, descriptions and ecology of each species. The exotic species brochure is part of a series of data sheets that form the ‘Watercourse Management Field Guide’ and are available in hard copy or electronic format. Data sheets aim to aid identification of some exotic fish species in the area, highlight impacts of exotic species, provide possible control options and direct people to further information and involvement.
NEW SOUTH WALES
NSW Weed Society • This site details activities of the society, which includes contact, newsletter, details of resource materials and links to other sites, a calendar of activities and information of a general botany as well as species information on weeds including wetland and riparian species.
NSW Fisheries • This site provides brief detail of the issues associated with invasive species within a PDF file "Aquatic habitat management and fish conservation 1999 update" including policy and legislation.
Department of Land and Water Conservation • DLWC are involved in water management within NSW. The website does not include extensive details concerning aquatic pest fauna issues although it provides valuable links to a range of other organisations associated with education. The site provides reasonable detail concerning water weeds in NSW wetlands including information on specific species, photographs, regulations and impacts.
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NSW Agriculture • This site provides details of the NSW Weed Strategy including desired outcomes, how they should be achieved and key participants. There are links to noxious weed lists (which include aquatic and semi- aquatic), legislation, protocols, management strategies etc. Information on fauna pests appears limited to terrestrial species.
NSW National Parks and Wildlife • This site provides some detail concerning pest animals and weeds. The pest animals information relates primarily to terrestrial species. The weed information provides links to further details from the Australian National Botanic Gardens including some detail on semi-aquatic and aquatic species.
Australian Museum • Freshwater and Estuarine Molluscs – An Interactive Key for New South Wales. CD ROM. This includes some pest species and while it is primarily technical in detail, it provides one of the only information guides for such species including distribution and impacts.
GENERAL AND NATIONAL RESOURCES
MDBC • The website includes some education projects such as "Special Forever", "Our Place" and "Waterlines". These are targeted at school students to provide awareness of issues relating to the Basin and its health. There are also interactive CD ROMs, videos and radio interviews. There is a communication strategy to coordinate a program of communication, consultation and education activities within the Basin.
Land and Water Australia • Riparian Management Booklets 1-7. These booklets cover a variety of issues including river ecosystems, snags in rivers and water quality. • RIPRAP – River and Lands Management Newsletter is a newsletter covering particular issues with each edition such as managing and rehabilitating riparian vegetation and managing snags and large woody debris. Rivers for the Future was a magazine previously published by LWRRDC.
Environment Australia • This website provides only limited information concerning riverine issues such as pest species although it includes a wide range of associated links. The website includes EnviroEd which establishes a national network of environmental education and information programs, materials and publications in the interests of education for sustainability. It includes a wide range of useful links for a range of levels of students, teachers and the community. • In relation to weeds, there is also the Alert List, a list of 28 non-native but already established plant species with the potential to threaten biodiversity, and the National Weeds Program, which funds weed- related projects through the National Heritage Trust.
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Australian National Botanic Gardens • The web site includes a listing of significant environmental weeds, and giving basic information on nature of impact, plant communities affected, but supported by excellent photography. As with most Botanic Gardens, the focus is entirely on native plants.
CSIRO • The CSIRO has science education centres in each capital city which include science laboratories for students with experiments and demonstrations. There is a magazine Scientriffic for students which includes activities and a teacher's guide.
CSIRO Entomology • The research program Weed Management, which has a proud tradition of research into biological control, includes some high profile wetland and aquatic plant species. Information sheets on selected species can be downloaded, and newsletter is available, including a wrap-up of biological control agents.
AQIS • Australian Quarantine and Inspection Service (AQIS) provides quarantine inspection services for flora and fauna into Australia. The AQIS website includes some educational information including games, lesson plans, a reference library and Quarantine Matters! CD ROM. The website includes a target list of weeds that include some aquatic/riparian species. The information is limited giving only a brief description of each species and the risk they pose.
AusRivAS
• "AusRivAS - assessing the health of our rivers" was produced by the Cooperative Research Centre for Freshwater Ecology and Land and Water Resources Research and Development Corporation. There is a training video for water management agencies, government departments and community groups with an overview of the sampling techniques used in the Australian River Assessment Scheme (AusRivAS). • An interactive guide to Australian aquatic invertebrates has been produced by CSIRO Entomology, LWRRDC and EA. ISBN 0 643 06515 6. The guide covers the macroscopic invertebrate taxa that occur in Australian inland waters. A fish guide could potentially be modelled on this CD-ROM.
Waterwatch • This is a national program which involves individuals, the community and school groups who undertake a variety of biological and habitat assessments and physical and chemical tests to understand the health of waterways and catchments. The Waterwatch Education Kit has many activities that relate to macroinvertebrates, water quality, habitat and catchment issues and is aimed at primary and secondary schools. The website includes an excellent community monitoring manual detailing all facets of monitoring as well as an equipment manual. There are also associated programs such as Streamwatch and Bug Surveys in States such as New South Wales. There would appear to be potential to incorporate pest species issues in such a program.
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WWFN • The World Wide Fund for Nature website refers to freshwater ecosystem management and highlights MDB as a current conservation hotspot. It mentions the introduction of exotic species as an issue although there is no detailed information provided.
ACF • There does not appear to be any specific information concerning pest species or weeds. There is limited background information concerning riverine and water issues including the MDB.
Gould League • This organisation is involved in environmental education, producing a range of material about natural history and the environment. It produces educational material and programs for schools including programs such as the "Amazing Ponding Adventure". There would appear to be potential for such programs to incorporate issues relating to invasive species.
Australian Society of Fish Biology • This society was established to promote fish studies and interchange of information between fish biologists. The website primarily comprises details about lists of publications, memberships, upcoming conferences and links to other organisations. The society publishes proceedings of conferences and newsletters. There is no specific information concerning pest fish species.
Australian and New Guinea Fish Association • This association promotes the conservation, study, keeping and propagation of native fish species in Australia and New Guinea. There are regional and affiliated groups in other States including within the MDB. It association publishes a journal Fishes of Sahul and an ANGFA Bulletin. The website does not specifically provide information on pest species.
NFA • Native Fish Australia is a volunteer organisation interested in the well-being of native freshwater fish and their environments. It provides some limited detail concerning exotic fish species.
RecFish • This is a peak national body for recreational and sport fishing and provides limited information on environmental issues. The website includes newsletters, links and a contact for the National Carp Task Force and Carp Location Database. This provides information on the aims of the task force, background information on carp, what can be done, where to find further information etc. The database enables the community's involvement in identifying where carp occur. The National Carp Task Force also produces a newsletter.
Australian Society of Limnology • This society focuses on the study and management of inland waters. It provides a forum for idea exchange and research results, an interface between researchers and managers, a venue for student development and also reports to State and Federal government concerning the status of inland rivers.
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There are volunteer expert contacts for particular issues including exotic species' ecology. It also provides policy statements on a range of issues including carp; the carp policy statement includes background information on the species, issues and recommendations. This represents a valuable form of easily accessible information on invasive species.
Cooperative Research Centre for Catchment Hydrology • Offer a range of short day, undergraduate and postgraduate courses on a range of catchment issues. Resource materials are being developed for secondary schools, management agencies and community groups on catchment management and behaviour. The CRCCH also provides advice to schools and communities as well as contributing to university education programs. It produces a newsletter Catchword.
Cooperative Research Centre for Freshwater Ecology • This group exists to improve the condition of Australia's inland waters. The CRCFE provides a diverse range of information on catchment issues, management, fish and macroinvertebrate ecology. It has an education program which aims to provide high quality education to the community, undergraduate and postgraduate levels concerning sustainable management of freshwater resources. School project kits are currently being developed.
CRC for Weed Management Systems • The CRC has an Education program with three sub-programs. Tertiary training, offering units at a number of regional universities in theory and practice of weed management, with the aim of fostering a new informed generation of weed scientists; and also support for post-graduate students. Professional development in weed identification, weed management and farm chemicals for practitioners. Community awareness which targets not just awareness but responsibility about weeds, principally through its WeedBuster Week and the active maintenance of 7 list servers on weed issues. There is also a Communication and Adoption program. • The website includes a newsletter, technical services and proceedings, handbooks and management kits. It also links to the Weed Navigator Resource Guide which represents a comprehensively guide which lists groups, agencies, publications, materials, resources and training activities concerning weeds in Australia and New Zealand. This includes email discussion groups for particular topics where interested people can regularly communicate and keep people up-to-date with events, new publications and other information. Environmental weed best practice management guides produced by CRC Weed Management Systems are mainly for species of agricultural and pastoral lands. • The six target taxa in the Natural Ecosystems program are bitou bush / Bone seed Chrysanthemoides monilifera, bridal creeper Asparagus asparagoides blackberry Rubus spp., broom Cytisus scoparius, St John’s wort Hypericum perforatum, and horehound Marrubium vulgare, do not include any obligate riparian or aquatic species though all may occur in the riparian zone.
Weeds Australia • This website aims to provide links to any weed management site in Australia including community groups, government, commercial or private individuals. The National Weed Strategy aims to promote access to key weed policies and regulations, current issues, national initiatives, research, extension
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training and personnel. It has set up a set of training competencies for weed management and highlights issues relating to new naturalisations and the importance of risk assessment, correct identification and management. It provides specific details for particular weed species and is a valuable source of educational material.
3.3 Conclusions and Recommendations This scrutiny of available educational information on invasive species indicates there is a wide variety of types of information already available (e.g. websites, posters, CD ROMs, brochures, school curriculum material etc). The material varies widely in: • how easily it can be found (e.g. by searches of key words in websites, CD ROMs that must be purchased etc.) • where it can be accessed from (e.g. State and Federal government, interest group websites etc.) • the level of information available (e.g. comprehensive reviews, limited mention etc.) • the audience it is aimed at (e.g. school curriculum, the general public, interest groups etc.)
An overall impression is that there is some comprehensive educational material already available within some government websites that provides useful accessible information concerning pest species. For example, the Queensland Department of Primary Industries has developed a range of material concerning pest fish in this state. One of the most frequently received comments within the aquatic pest questionnaire highlighted this educational material, indicating that it is already quite well known. Many state government departments have some targeted material relating to specific species or research and management programs (e.g. for carp). Others appear to have very limited information that is easily accessible concerning pest or weed management. As would be expected, material is spread between different departments, reflecting their varying responsibilities and involvement in such issues. There is also some specific educational material related to particular local or regional areas (e.g. Upper River Torrens Landcare Group brochures on exotic species). In relation to weeds, there seems to be a more comprehensive national approach (e.g. National Weed Strategy) and this has resulted in targeted information dissemination via websites. In relation to invasive fauna, some websites seem to have a greater amount of information concerning marine species in comparison to freshwater species. There is however a very clear need for even basic information concerning invasive invertebrate species. Invertebrates may be overlooked due to their small size, relative ‘invisibility’ and perceived unimportance compared to vertebrates which are usually much larger and more visible species such as carp. Differences in available information can in part be attributed to differing commercial, agricultural and recreational interests e.g. agricultural weeds become a priority due to production losses and carp are a priority due to impacts on recreational and commercial fishing as well as water quality issues. Policy and associate research have been more directed to those areas of particular economic interest which also perpetuates this situation.
As is true of government department websites, there is also a clear variation in educational material available through websites for interest groups such as fishing groups and conservation groups. Some such as RecFish have links to specific programs such as the National Carp Task Force and some have limited information concerning particular invasive species.
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The need for an educational program specific to the Murray-Darling Basin has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). They noted that people have some degree of understanding of ecological and economic effects of some pest species, but few recognise the connection between their own activities and the accelerating rate of invasions.
Recommendations arising are: • The development of a Basin-specific Invasive Species Education Program. • The development or adoption of a conceptual framework based on the invasive process, similar to the meshing of goals and objectives with process as done for the National Weeds Strategy (Section 1.3).
3.4 Murray-Darling Basin Invasive Species Education Program There is a clear need for the development and implementation of an invasive species education program within the MDB to foster recognition and understanding to a range of individuals and groups which include:
• State and Federal and regional government department staff - ensure they are aware of relevant information to provide appropriate information to others and to inform their management and decision- making. • Interest and industry groups - e.g. conservation groups, user groups (aquarium industry, fishing groups, Landcare groups, Waterwatch groups, nurseries etc.) • Schools - both teachers and students at the range of levels from primary, secondary to tertiary.
Particular issues which need to be addressed within the MDBC Invasive Species Education Program include:
• The importance of the public’s role in the introduction and spread of invasive species (e.g. deliberate or accidental translocations through dumping of weeds and aquarium animals, movements of vehicles and boats) • Methods of dispersal/transportation of invaders by human agents (e.g. aquarium trade, horticulture and nursery trade, recreational fishing groups, illegal pet trade) • Ecological, social and economic impacts of invading species (e.g. predation, competition and hybridisation with native species, habitat alteration, production losses in industry, vectors of disease, cost of control, decreased water quality and availability, flooding) • Differing potential for invading species to develop into pests and/or have detrimental impacts (e.g. opportunistic invading species taking advantage of altered/disturbed habitats, invading species being constrained by biotic and physical factors which limit or negate their establishment). This highlights the need for risk assessment as a means of identifying key pest species to target in educational packages. • Some invaders that have not yet become established in Australia can have potentially disastrous ecological, economic and social effects and eradication warrants a coordinated rapid response approach. Education packages need to highlight these cases to emphasise the seriousness of invasive species, their impacts and methods of control. • The observed connection between environmental degradation, disturbance and invasion success i.e. in degraded/disturbed habitats the invading species may often be a symptom rather than a cause of the problem. Addressing factors that cause degradation (e.g. clearing of vegetation, unfenced grazing, desnagging, runoff) are important in the overall education and management of invasive species. These
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issues must form an integral component of any environmental management program e.g. rehabilitation, undertaken in the MDB. • Control and eradication programs can be successful given effective technology, adequate resources and community support and require cooperation between groups involved. Highlighting these successes in educational material ensures positive messages are generated therefore encouraging support from the wider community.
The MDBC Invasive Species Education Program needs to be developed as a comprehensive program tackling the range of aquatic and riparian flora, and aquatic fauna which are already pests or have the potential to become pests. This must include the range of taxonomic groups and address obvious gaps in existing information for groups such as invertebrates. It should include a range of educational elements to meet the particular needs, interests and accessibility issues of the range of groups.
Key tasks of the MDBC Invasive Species Education Program should include: • Undertake a more comprehensive review of existing information concerning pest species within the MDB. • Consideration of which existing aquatic-related programs and websites etc. could possibly be expanded to incorporate invasive species information. • Determination of the range of end-user and community groups which educational programs need to target. • Identification of potential barriers in educating particular groups (e.g. due to social and/or cultural views where pest species are not considered ‘pests’ or detrimental) and develop appropriate methods to address these issues and effectively disseminate information. There is also a need to recognise barriers to understanding the detrimental aspects of pest species and to try to tackle these complex social issues. A major barrier is the public’s perception and understanding of what constitutes an invasive species and this also serves to highlight the conflict of interests in the broader community. For example, trout are considered a valuable angling and commercial fish while some ethnic groups value carp as part of cultural tradition. This can lead to the problem of generating mixed messages e.g. a recent article on the negative impacts of Koi carp in New Zealand also referred to beneficial angling characteristics of this species. Thus educational approaches need to have a degree of empathy for the range of views held by the public, while focusing on educating them about potential detrimental impacts of pest species. • Identification of key misunderstandings and knowledge gaps concerning pest species including their introduction, spread, impacts and available methods of control. There are significant differences in public awareness and the impacts of their activities on the aquatic environment, due to differences in issues, impacts, perceptions, interests, available information and misunderstandings. General misunderstandings of invasive species may arise through misinformation, lack of education (e.g. many people believe trout is native), and confusion between native and introduced species that look similar (e.g. alligator weed and lesser joyweed, parrot's feather and native milfoils). This emphasises the need for any MBD educational packages to reflect these differences in public awareness of invading species and packages need to involve a broad spectrum of approaches that reflect the knowledge base and key issues relevant to target groups while recognising and addressing key misunderstandings. • Identification of what information needs to be disseminated to the range of target groups. All educational material must be accessible in a variety of forms to reach all identified target groups e.g. brochures,
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booklets, posters, activity and resource kits for schools, media stories (current affairs, ABC Landline, newspaper and radio articles). The material also needs to have a MDB context that can provide comprehensive information at a Basin-wide level as well as more specific state-oriented information. This information could include an invasive species resource guide (e.g. Weed Navigator 1998) on the internet and possible as hard copy as a reference tool for invasive species within the MDB. In order not to overwhelm the public with huge lists of invading species which could provide an impression that no advances have been made, there is a need to target a selection of key species that have been carefully chosen to reflect what can be done, what has already been done and which actions will bring the best results. • Development of targeted material for each group to improve their understanding and identification of the current and potential pest species within the MDB. This should consider how different material will be appropriate for different audiences to ensure material is most effective and most easily accessible. For example, government department sites should be seen as a key initial contact source for information or as clear direct links to appropriate information. Rather than repeat similar information at a range of sites, there should be main comprehensive sites (e.g. the MDBC website) which link directly. Key interest group sites which have large memberships should be targeted as direct links. A wide range of websites should also include key search words "pests" and "weeds". Websites would be a very valuable primary educational tool given that a large proportion of the population now regularly uses the internet as an information source. Beneficial aspects of websites are that they can be easily accessed, provide downloadable information and can be readily updated.
Key aims of the education program should be to: • Promote the public’s role in minimising the introduction and/or spread of invasive species. Activities that can be modified include the use of pest species as bait, release of aquarium fish and plants, dumping of rubbish and garden waste, washing of machinery, boats, trailers and nets, not returning exotics to water when fishing, and protection of riverine environments. • Foster a sense of ownership and encourage active involvement of these groups in preventing introductions and spread, and to reduce the impacts of exotics (e.g. knowledge generation, behaviour modification, habitat rehabilitation), particularly by use of pre-emptive measures such as animal and weed hygiene measures. • Ensure the range of audiences are able to correctly identify pest species or have contacts for expert identification, and highlight cases where pest species could be confused with native species. • Ensure urgent information on current or potential pest species could be incorporated to allow for a fast and effective response to emerging problems within the MDB. This could include the development of advisory material on how to collect suspect species and what to do with it (e.g. how to preserve, who to contact etc.) to ensure appropriate identification. • Enable the public to provide information on the location of key current and potential pest species, as part of a coordinated program. As well as facilitating knowledge generation and community ownership, such a program would highlight species for which we require distributional information. An improved understanding of the distribution of particular species, particularly those with limited distributional information will potentially assist in determining and implementing appropriate management and control programs and restricting further spread.
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4 Identification of Current and Potential Pest Species - Fauna
4.1. Methods A questionnaire was developed to obtain information from experts on pest fauna species within riparian and aquatic environments within the MDB. The circulation of a questionnaire was seen as the most efficient method of obtaining expert advice in a short period of time. The fauna questionnaire was sent to 78 people (Table 6) representing a mix of experts from each state within the MDBC as well as outside the Basin and including both researchers and managers who deal directly with the issue of pest fauna. Although the survey asked for suggestions of any additional people we should contact, the limited timeframe for the project prevented further people being sent the questionnaire. The total of 23 replies included eight from Victoria, six from Queensland, four from New South Wales, two from the ACT, one from South Australia, one from Western Australia and one from Tasmania. Participants were asked to indicate how they were involved in activities relevant to policy development, management of, and/or research into, the effects of pest species on freshwater environments. This information assisted us in interpreting subsequent information provided by participants.
The questionnaire was distributed in early May 2001 (see Appendix 1), with an attached letter providing an explanation of this MDBC project and providing a month for reply. The total number returned was 23 (29.5%) which included several late replies. While those who replied varied in both the amount of information they supplied and the method of filling in answers, valuable information was obtained from the survey, which assisted in the development of project briefs. A summary is provided below of responses to key questions. The original questions are provided in italics.
Table 6: Circulation list for fauna questionnaire First Last Location State Stuart Bunn Griffith University, Faculty of Environmental QLD Science Satish Choy Department of Natural Resources QLD Peter Jackson Queensland Fisheries Service QLD Claire Peterken Queensland Fisheries Service QLD Michael Hutchison Queensland Fisheries Service QLD Rachael McKenzie Queensland Fisheries Service QLD Alf Hogan Queensland Fisheries Service QLD John Russell Queensland Fisheries Service QLD Norm Millward James Cook University QLD Richard Pearson James Cook University QLD Angela Arthington Griffith University QLD Brad Pusey Griffith University QLD Mark Kennard Griffith University QLD Jeff Johnson Ichthyology, Queensland Museum QLD Kath Bowmer Charles Sturt University NSW
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Table 6: Circulation list for fauna questionnaire (cont') First Last Location State Peter Gehrke NSW Fisheries NSW David Pollard NSW Fisheries NSW Ivor Growns NSW Fisheries NSW Andrew Sanger NSW Fisheries NSW Bill Talbot NSW Fisheries NSW John Harris Consultant NSW David Harris Department of Land and Water Conservation NSW David Leslie Department of Land and Water Conservation NSW Patrick Driver Department of Land and Water Conservation NSW Bruce Chessman Department of Land and Water Conservation NSW Greg Williams Inland Rivers Network NSW Paul Humphries Murray-Darling Freshwater Research Centre NSW Winston Ponder Curator of Mollusca, Australian Museum NSW Adrian Wells National Carp Taskforce/Murray Darling Association NSW John Hawking Murray-Darling Freshwater Research Centre NSW Robyn Watts Charles Sturt University NSW Wayne Erskine State Forests of NSW NSW Phil Suter La Trobe University VIC Andrea Brumley East Gippsland Community College of TAFE VIC John Koehn Department of Natural Resources and Environment VIC Wayne Fulton Department of Natural Resources and Environment VIC Paul Brown Department of Natural Resources and Environment VIC Alan Baxter Department of Natural Resources and Environment VIC Sam Lake Monash University VIC Jon Leevers North Central Catchment Management Authority VIC Paul Atherton Wimmera Catchment Management Authority VIC Tony Overman Corangamite Catchment Management Authority VIC Keith Ward Department of Natural Resources and Environment VIC Pat Feehan Goulburn Murray Water VIC Graeme Creed Native Fish Australia VIC Wayne Tennant Goulburn-Broken CMA VIC Rob O’Brien Department of Natural Resources and Environment VIC Ben Gawne Murray Darling Freshwater Research Centre VIC Michael Shirley Sinclair Knight Merz VIC Max Moor National Carp Taskforce/Murray Darling Association VIC Peter Davies University of Western Australia, Department of WA Zoology Pierre Horwitz Dept Environmental Management, Edith Cowan WA University
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Table 6: Circulation list for fauna questionnaire (cont') First Last Location State David Morgan Murdoch University WA Howard Gill Murdoch University WA Anthony Scott CSIRO Land and Water ACT Brian Lawrence MDBC ACT Jim Barrett MDBC ACT Mark Lintermans Parks and Conservation Service ACT Richard Tilzey Bureau of Rural Science ACT Mary Bomford Bureau of Rural Science ACT Mike Braysher University of Canberra ACT Bob Kearney University of Canberra ACT Francis Michaelis Australian Quarantine Inspection Service ACT Bryan Pierce South Australian Research and Development SA Commission Keith Walker University of Adelaide SA Michael Geddes University of Adelaide SA Michael Hammer University of Adelaide SA Peter Shultz Australian Water Quality Centre SA Patricia Kaiola Consultant TAS John Diggle Inland Fisheries Commission TAS Peter Davies University of Tasmania, Zoology Department TAS Brian Smith Queen Victoria Museum TAS Roland Griffin NT Parks and Wildlife NT Andy Wattam ANGFA ACT Glen Briggs ANGFA VIC Adrian Dawson ANGFA QLD Derek Girkin ANGFA NSW Robert Marshall South Australia Native Fish Association SA
4.2 Questions and Answers
1. Identification of knowledge gaps Table 2 summarises the principal current and potential aquatic pest fish species within the MDB1. We seek your opinions on the significance of the threat that each species may pose to the aquatic environment (and its associated flora and fauna). Please provide comments as to your reasons behind rankings (e.g. ease of spread, reproductive capacity, evidence of environmental degradation, economic impacts etc.). We recognise you may not be familiar with all species and you may omit any species you do not wish to comment on.
1 This list has been obtained from reviews of introduced species e.g. Arthington and Blűhdorn (1995) Improved management of exotic aquatic fauna: Research and development for Australian rivers. LWRRDC Occasional Paper 04/95, and Arthington and McKenzie (1997) review of impacts of displaced/introduced fauna associated with inland waters. State of the Environment Technical Paper Series (Inland Waters).
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Instructions a) Please rank the significance of current and potential pest species from 1 (most important) to 13. b) Please provide any comments to explain your ranking. c) Please add any other fish species you believe should be on this list (NB: Ornamental fish are addressed later in this questionnaire).
Results:
Table 7: Current and potential aquatic pest fish species in the MDB Species Ranking Carp Cyprinus carpio 1 Gambusia Gambusia holbrooki 2 Goldfish Carassius auratus 3 Redfin Perca fluviatilis 4 Weatherloach Misgurnus anguillicaudatus 5 Brown Trout Salmo trutta 6 Tilapia Oreochromis mossambicus 7 Rainbow Trout Oncorhynchus mykiss 8 Tench Tinca tinca 9 Roach Rutilis rutilis 10 Guppy Poecilia reticulata 11 Atlantic Salmon Salmo salar 12 Brook Trout Salvelinus fontinalis 13
Some respondents indicated that it was difficult to provide a simplistic ranking of pest species and either did not provide scores or provided a 'high', 'medium' or 'low' ranking. The overall ranking provided by respondents was generally as would be expected. Carp which ranked highest is a widespread and abundant species across most of the MDB and has a high profile in relation to impacts to the environment. Gambusia (2nd) is similarly ubiquitous in the Basin. The high ranking of goldfish (3rd) is relatively surprising; while it has a wide distribution and is abundant in areas, little is known of its impacts. Redfin (4th) and trout (6th and 8th) are known to predate upon native species. Weatherloach (5th) and tilapia (7th) are more recent invaders and their impacts on the environment are not well known. Species with far more restricted distributions and less apparent impacts, such as tench, roach, guppy, Atlantic salmon and brook trout received lower rankings.
A summary of comments provided by respondents on their reasons for rankings: Carp Cyprinus carpio Since the 1970s carp have spread and devastated most freshwater wetlands in northern Victoria. Widespread, occurs in huge numbers, still spreading north and adapting to cooler water. A hardy species with a huge breeding capacity and tolerance to a range of environmental conditions and likes disturbed habitats. Impacts not quantified but those attributed to the species include damage to substrates and floodplain vegetation, degradation of water quality, cause of turbidity, alteration of habitats, domination of populations,
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 43 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire competition with native fish, a vector for disease. It is a social issue, currently a highly visible problem and a major concern to the public. There are limited management options.
Gambusia Gambusia holbrooki Very widespread and abundant, and can be numerically dominant. More problematic in regions without variable water regimes and less of a problem in flowing waters. A significant threat, spreads easily, may have serious impact on small native fish species and macroinvertebrates through predation and competition. A highly aggressive species, high reproductive potential, hardy with a tolerance to a range of conditions, may completely rearrange trophic structures. May potentially spread diseases. Could still be dispersing by humans. Difficult to eradicate, no management options.
Tilapia Oreochromis mossambicus Detected in the north of the Basin, its distribution may be limited by water temperature although potential for cold resistant strains to spread south which would represent a high potential threat. Profound threat due to adaptability/competitiveness, high potential for spread, high reproductive capacity. Impact unknown in Australia, although known to have serious impacts elsewhere. Could have high impact on fishery and is a favoured food fish. Wide environmental requirements, has spread significantly in other areas. Can dominate biomass.
Weatherloach Misgurnus anguillicaudatus Increasing in distribution and abundance rapidly, still actively spreading, and is used as bait by humans. Potential to disperse over wide area. Extreme tolerance to arid rivers/floodplain conditions, indestructable, highly fecund, long lived, eurythermal. While impacts are unknown, may have high potential for impacts and research is required. Potential impacts may include predation. Are becoming more of a concern.
Goldfish Carassius auratus Widespread, can exist in very high density including in weedbeds and have been in the MDB for a long time. High breeding capacity, widely used for live bait, and can clear out cattle troughs of algae. May be a moderate threat and are more of a threat in warmer waters. Impacts and management options not known, as yet no significant effects shown. May compete with native species. Possible link with problems caused by common carp and supposedly cross breed with carp.
Redfin Perca fluviatilis Now in moderate numbers, seems to be pretty well under control at present. Breeds over a wide area, not in Queensland. Limited by EHNV and temperature. Has had a major unquantified impact in the past. Fecund, voracious feeders, very efficient piscivore, predator of native fish including galaxiids and pygmy perch, a threat to many small native species, can be a dominant predator in billabongs. Huge threat as a vector of EHNV. Highly regarded by anglers.
Brown Trout Salmo trutta An example of a species with the most quantifiable impacts e.g. predation. Demonstrated effect on a wide range of fauna. Galaxiid populations strongly declining due to this predator, and they can also prey upon blackfish and crayfish. Voracious feeders. Potential to spread via human translocation, distribution not expanding. Temperature limited, not likely to occur in most lowlands. Potential spread and damage realised,
44 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire no new threats. Done about as much damage as they are going to. Continuously stocked and doubt would remain an issue without stocking programs. Potential vector for spread of EHNV.
Rainbow Trout Oncorhynchus mykiss An example of a species with quantifiable impacts e.g. predation. Galaxiid populations have strongly declined due to predation, and they can prey upon blackfish and crayfish. Voracious feeders. Potential spread and damage realised, no new threats. Done about as much damage as they are going to. Distribution limited to cold waters, in slopes and uplands, not in northern Basin and not expanding. Possibly less concern compared to Brown Trout with more limited environmental tolerances. Continuously stocked and doubt would remain an issue without stocking programs. Potential vector for spread of EHNV.
Roach Rutilis rutilis Limited range, unlikely to expand, does not appear to be expanding into NSW and may have declined. Actively dispersing by humans. Little information on impacts, none known.
Guppy Poecilia reticulata Low potential threat, limited by low winter temperature tolerance Limited numbers. Impacts largely unknown, some impacts on small native fish, aggressive and rarely found with native species.
Tench Tinca tinca Limited range, unlikely to expand with low rate of spread, still abundant in isolated areas although actual numbers not known. May have declined, not observed in recent years and has almost disappeared in NSW. Not highly targeted by anglers. Little information on impacts, none known. No management options.
Brook Trout Salvelinus fontinalis May be a potential problem. However, they have an extremely limited range, require very low temperatures, will not spread, limited breeding possibly in alpine areas. There are no known wild populations, maintained for recreational purposes by stocking. Prefers step pool habitats which are limited in Australia.
Atlantic Salmon Salmo salar May be a potential problem. However, extremely limited range and are not breeding. No wild populations known, maintained for recreational purposes by stocking. Limited by water temperature.
2. Management and Research Options Table 3 provides a list of broad management and research options for aquatic pest fish species within the MDB. The table includes columns for each of the 13 current and potential species identified above.
Instructions a) Please tick boxes to indicate which options you believe are important and which would be a suitable basis for projects. Please add any other management and/or research priorities in the space provided at the end of this table.
Results: Results are given in Table 8.
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Table 8: Management and research options for aquatic pest fish species Issue Carp Gambusia Tilapia Weather- Goldfish Redfin Brown Rainbow Roach Guppy Tench Brook Atlantic Total loach Species Trout Trout Trout Salmon
• Interactions with native species (e.g. 17 15 12 11 8 12 10 9 5 5 3 4 2 113 competition/predations) • Aquatic fauna (e.g. fish, 16 14 11 13 7 11 9 9 5 4 3 3 3 108 invertebrates) • Education 9109 8 5 7 8 8 55 64 4 88 • Behaviour (e.g. species interactions) 13139116 655 54433 87 • Change in biodiversity 151098 8 655 33222 78 • Biological control (e.g. introduction 16128104 622 43222 73 of viruses, immunocontraception) • Population status and distribution 98 10104 7 3 3 44 42 2 70 • Eradication techniques (e.g. 149 10102 4 4 3 21 12 2 64 poisoning) • Coordination of management (e.g. 149 8 8 4 6 3 2 12 31 1 62 States, groups) • Physiological tolerances (e.g. 107 109 4 4 2 2 34 21 1 59 salinity, temperature) • Diseases, Viruses 108 75 5 922 433 58 • Documentation of trend (e.g. rate of 76 10112 4 3 2 33 11 1 54 spread) • Environmental manipulation (e.g. 151065 2 411 12111 51 flow manipulation) • Diet 79 3 7 5 6 3 2 21 21 1 49 • Reduction in abundance (e.g. 156 54 2 344 1 22 48 harvesting) • Biomanipulation (e.g. manipulating 139 67 2 411 121 48 interrelationships between species and environment for ecological balance) • Strategies/Management processes 89 4 6 4 6 3 3 12 11 1 48 • Ecological processes (e.g. nutrient 166 46 8 222 1 47 cycling)
46 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire Table 8: Management and research options for aquatic pest fish species (cont') Issue Carp Gambusia Tilapia Weather- Goldfish Redfin Brown Rainbow Roach Guppy Tench Brook Atlantic Total loach Trout Trout Trout Salmon • Aquatic flora (e.g. macrophytes) 16 2797 311 46 • Habitat preferences/requirements 7598 4 311 11 2244 • Movement (e.g. migratory patterns) 10558 4 311 3111144 • Reproduction (e.g. spawning cues, breeding 1197841 12 43 biology) • General biology (e.g. growth, longevity, 7566 3 311 2112241 maturity) • Prevention of introduction (e.g. barriers) 12264 1 355 1 1141 • Water quality (e.g. turbidity, algal blooms) 17445 4 222 1 41 • Habitat restoration (e.g. revegetation, 13662 5 211 1 37 resnagging) • Reintroduction of native species 9663 3 132 111 36 • Economy (e.g. decline in commercial, 12451 1 344 1 35 recreational fishing opportunities) • Social (e.g. aesthetics) 11442 3 233 1 1 34 • Identification of appropriate survey 784522 111 31 techniques • Improved consultation (e.g. identification of 4242 2 253 1211130 appropriate experts, interest groups) • Documentation of historical information 3245 1 211 3121127 (e.g. introduction) • Riparian environment (e.g. bank erosion) 15 2 2 2 1 22 • Importation/Introduction controls 73 6 3 1 1 21 • Genetics (e.g. sterile) 52 4 2 3 16 • Data collection and interpretation 3332111 1 15 • Monitoring/Research 322411 1 14 Other categories suggested by respondents Interaction also covers natives 1111 1 111 1111113 Habitat rehabilitation for natives 1111 1 111 1111113 Quantification of acceptable impact 111 3 TOTAL 400 244 238 230 135 126 100 91 72 64 53 41 38
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Species Ranking The breakdown of total scores for each species provide relatively predictable results and corresponds reasonably well to the significance indicated in Table 7. In Table 8, respondents indicated that research and management should be focused predominantly on carp, followed by gambusia, tilapia and weatherloach. Carp is a very widespread, dominant and highly visible problem in waterways within the MDB. Gambusia, while a less conspicuous species, is also widespread and dominant. Tilapia has received attention in recent years with possible records within the MDB, and respondents may consider that focus on the management of this species may limit its potential to establish within the MDB. Weatherloach represents a relatively recently introduced species which is spreading rapidly and where very little is known of its impacts.
Goldfish, redfin and brown trout and rainbow trout received a moderate ranking. While species such as the brown and rainbow trout are known to have detrimental impacts, several respondents commented that their distribution is temperature limited, they are not spreading and the level of damage they have caused is not likely to increase. Many believe that redfin, while they are likely to have had an impact in the past through predation, now only occur in moderate numbers. While goldfish are widespread and can occur in high densities, their impacts are not well understood and do not appear to be significant.
Much lower scores were given to roach, guppy, tench, brook trout and Atlantic salmon. Very little is known of the possible impacts of roach, tench and guppy, their distributions are limited and do not appear to be rapidly expanding. Brook trout and Atlantic salmon also have very restricted ranges and are limited by temperature tolerances.
Issues Ranking The issues provided within Table 8 were initially broadly separated into Monitoring/Research, Impacts and Methods of Control/Management. There was no clear dominance in ranking between these categories. The results indicated that of the five highest ranking issues, four follow a similar theme i.e. the varying types of interactions and impacts associated with introduced species (investigation of the interactions with native species, impacts on aquatic fauna, behaviour between native and invading species, and changes to biodiversity). The need for education as a method of managing introduced species received the third highest ranking.
The six to tenth highest ranking issues related to methods of controlling introduced species, clarification of the distribution and population status of particular species, improved coordination in management, and investigation of physiological tolerances. Control techniques which ranked highly included direct practical eradication techniques such as poisoning, as well as more long term strategic methods of biological control which may potentially provide eventual answers to broadscale eradication. Clarification of the current distribution and status of species such as weatherloach and tilapia, species which are actively spreading and may have recently entered the MDB respectively, are clearly important projects. The need for coordination of management highlights that many species are currently managed in an inconsistent, ad hoc and state-based manner. The recent approach of establishing a National Carp Task Force indicates the growing recognition of the value of a more coordinated management approach. Investigation of particular key physiological tolerances of introduced species may provide a better understanding of the existing and potential environments within the MDB as well as suggest potential methods of management and control.
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The five issues which ranked as the least important related to management issues such as improved consultation, documentation of historical information, importation/introduction controls, data collection and interpretation and a research issue of investigating the impacts of introduced species on riparian vegetation (e.g. bank erosion). These rankings may reflect beliefs of respondents that there is sufficient information already available concerning introduced species to tackle their management and that importation controls are adequate. The low ranking of investigating impacts of introduced species on riparian vegetation is not surprising since most species are considered to primarily affect the instream environment.
3. Ornamental Fish Species There is an extensive review of the quarantine risk potentially associated with the importation of ornamental finfish into Australia (Arthington et al. 1999). This document provides lists of the large number of ornamental finfish species which are recorded and established in Australian waters as well as potential introductions. Are there any species of ornamental fish which you are particularly concerned may be released and/or become established in the MDB? Please specify.
Results: The majority of respondents who replied to this question indicated their concern over species of cichilds such as tilapia. One highlighted his concern over the red devil (Amphilophus citrinellus), a euryhaline species which has established self-maintaining populations in several Queensland impoundments, and which is considered to have a very high probability of further invasion in Australia (Arthington et al. 1999).
Several respondents expressed concern over cyprinidae species (a family which includes carp and goldfish). It was noted that koi carp breeders promote and distribute these fish and that goldfish also continue to be released and represent a risk by introducing new pathogens. One indicated concern over the tinfoil barb (Barbodes schwanenfeldii), a species which Arthington et al. (1999) note a considerable probability of establishment in Australia. One respondent indicated concern over the introduction of piranhas (Serrosalmus spp.). Several respondents expressed concern over poecilidae species, a family of livebearers which includes guppies and swordtails. One respondent mentioned cyprinodontidae, pupfish.
One respondent indicated that banded grunter (Amniataba percoides), a native species, is currently sold as an aquarium fish. Populations have apparently already established in the Brisbane River outside their natural range. It was noted that this species is considered undesirable by anglers and is a potential competitor with silver perch and also eats their fry.
4. Vertebrate Pest Species Are you aware of any other current or potential aquatic vertebrate pest species? Please specify?
Results: Few replies were received for this question; these included foxes in relation to their predation on turtles, axolotyls, cane toads and the painted turtle. Foxes are known to predate upon eggs of the Murray River tortoise (Thompson 1983) and there is also anecdotal evidence that foxes prey on platypus, frogs and reptiles that inhabit the riparian zone (A. Robley, DNRE, pers. comm.). Cane toads occur in and around freshwater
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 49 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire habitats and their range is continually expanding. Toads can affect the ecology of ecosystems by altering species interactions and algal assemblages (Alford and Crossland 2001). Current distribution appears to possibly include part of the northern area of the Basin in Queensland. An NRM Fact Pest Series Sheet (Queensland Department of Natural Resources and Mines) indicates that cane toads are only limited by environmental factors such as availability of water for breeding, tolerance temperatures, suitable shelter and abundance of food. The painted turtle (Chrysemys picta) is a species that has established in a number of countries outside its natural range, including England, Asia and New Zealand. This species has established populations in the Sydney region, is a generalist and cold tolerant, and is likely to be invasive if it established within the MDB (Arthur Georges, University of Canberra, pers. comm.). Further expert opinion could not be obtained.
5. Aquatic Invertebrate Pest Species An extensive review of introduced freshwater invertebrates within the MDB has not been undertaken, however a small number have been identified in reviews such as Arthington and Blűhdorn (1995). Are you aware of any current or potential aquatic or riparian invertebrate pest species? Please specify?
Results: Few respondents provided comments for this question and the majority of comments related to the three species of freshwater crayfish which are farmed in Australia (i.e. marron, redclaw and yabbies). The principal species highlighted was marron (Cherax tenuimanus). This species, which is endemic to Western Australia, now occurs in South Australia, southern Queensland and throughout New South Wales in farm dams and aquaculture ponds. One respondent noted populations have been recorded on the Mornington Peninsula and the Hopkins River Basin (Merri River). The actual distribution of the species within the MDB is not clear. Potential problems associated with this species include the introduction of disease, competitive interactions with native species and habitat alterations. Some respondents indicated concern over redclaw crayfish (Cherax quadricarinatus), a species native to northern Queensland, Northern Territory and Papua New Guinea. Commercial farming of redclaw crayfish commenced in the late 1980s. One respondent noted the species is widely translocated illegally in Queensland, with some reports of introductions into farm dams in the northern parts of the MDB. One respondent indicated that yabbies were of concern in Western Australia; yabbies were introduced into that state about 70 years ago and unauthorised stockings from interstate are prohibited and considered to pose significant disease and environmental risks (www.wa.gov.au/westfish/aqua/).
One person indicated that Physa acuta, a species of snail which is believed to be introduced may cause exclusion of native species. This species now has an extensive distribution within the MDB, can occur in high densities and can tolerate a range of environmental conditions.
6. Translocated Native Species The definition of a 'pest' may include native species which have been released into areas outside of their natural ranges for purposes such as recreational fishing. Are there any native species which you consider may be, or may potentially be, pest species where they occur outside their natural range (e.g. golden perch Macquaria ambigua, marron Cherax tenuimanus)
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Results: The most frequent comments received related to native species in the north of the MDB including sleepy cod (Oxyeleotris lineolatus), banded grunter, sooty grunter (Hephaestus fuliginosus), Barcoo and Welsh's grunters (Scortum barcoo & Bidyanus welchi). Several noted concern over the potential for hybridisation and competition with natives e.g. Barcoo and Welsh's grunters with silver perch. One respondent noted that some recreational fishermen were lobbying to stock barcoo grunters outside their range and that while this was unlikely to be approved, some may do so anyway and cited that this had happened in the case of sleepy cod. One respondent noted that sooty grunters and sleepy cod have established populations outside their natural range in Queensland and that there is evidence sleepy cod has detrimental effects on native species.
A range of other species were mentioned as of concern within the MDB and in other areas such as Western Australia. These include large angling species such as Murray cod, freshwater catfish, silver perch, Australian bass and golden perch. One respondent noted that Murray cod had been implicated in the decline of Australian grayling and blackfish in the Yarra River as early as 1875. Some respondents also referred to the translocation of aquaculture species such as barramundi. One respondent indicated concern over the translocation of climbing galaxias, a species which may be translocated through interbasin transfers or as bait. Other respondents noted that small northern native species can be moved around when used as bait.
Some general, in principle, comments were also received: • any species outside its natural range is a pest or has the potential to become a pest • any misguided restockings and translocations which do not consider genetic structure or inbreeding of broodstock are a concern • translocation of native species is not as significant an issue as compared to introduced species.
7. Research Priorities Based on your comments in Table 3 and previous questions, do you wish to provide further information concerning suitable research projects which are needed to address the issue of aquatic pest fauna species? If so, please specify below. Please elaborate on any research priorities that you have identified as important for aquatic pest species. (Optional)
Results: A range of ideas for research projects was provided which have been separated broadly into the following general categories: control, assessment of impacts, collection of information and management.
Control ♦ Investigate biological control techniques e.g. disruption of breeding success including inducement of sterility in male tilapia, introduction of fatality genes ♦ Investigate the use of diseases (e.g. specially modified viruses) to control carp. A respondent noted this would involve a long term project with animal health laboratories, and would include identifying potential organisms, reviewing them in detail, undertaking experiments in controlled facilities with the best prospects, refining and modifying organisms, and evaluating them in field tests.
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♦ Trial carp exclusion barriers ♦ Investigate all methods of controlling carp and goldfish ♦ Investigate site specific poisoning at early stages of infestation of introduced species.
Research on Impacts/Collection of Information ♦ Quantify impacts of introduced species, delineate their distributions, trial control measures at pilot sites and take a predictive approach ♦ Determine the potential impact of tilapia in the MDB which should include undertaking specialist workshops to identify priorities and options followed by implementation of priority actions. ♦ Investigate interactions between trout and native galaxiids and Macquarie perch ♦ Investigate the impacts of gambusia on native fauna as well as desirable introduced species ♦ Screen a broad range of south-east Australian native and exotic species for susceptibility to EHNV. This should include testing for antibodies in wild fish populations to see if they have been exposed and survived the virus, in particular Macquarie perch and silver perch. Methods of prevention of dispersion of EHNV should also be investigated ♦ Determine the effects of improving fish passage on introduced fish species ♦ Review the findings of a recent CRCFE report by Kennard et al. (2001) concerning the diets of native versus introduced species to identify the potential for interactions such as competition and piscivory ♦ Determine the habitat requirements/preferences of introduced species. This can be done quantitatively in the case of Queensland coastal rivers (Arthington, pers. comm.) ♦ Investigate the effects of introduced species on food web structure, using stable carbon and other isotopes to determine food resource base of native species in the presence and absence of key introduced species. Any differences in food web structure could be related to this information. This could include investigation of energy flow, depending on food web alterations ♦ Relate the distribution of introduced species to environmental change. This could include collaboration of researchers, consultation through conferences etc ♦ Determine the distribution of carp and goldfish in the upper MDB catchment ♦ Document the rate of spread of key introduced species and clarify their distribution by targeted surveys ♦ Undertake a brief review of protocols for appropriate survey techniques for introduced species ♦ Undertake targeted research on general biology, physiological tolerances, movement and behaviour of key introduced species to fill knowledge gaps ♦ Assess the potential of welch's grunter to hybridise with silver perch to produce viable offspring ♦ Identify genetic strains of introduced species with high dispersal capabilities and high reproductive potential
Management ♦ Determine the effect of stocking predatory native fish on introduced species in open river systems ♦ Investigate the potential for reintroduction of native species in selected sites ♦ Investigate the value of habitat restoration for key species
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8. Research and Management Approaches Can you provide examples of research and/or management approaches that you consider to be particularly useful in addressing the impacts and/or management of aquatic pest species? (For example, a field based approach as opposed to a laboratory based approach or community implementation rather than a management initiative). Please indicate target species if appropriate.
Results: Respondents provided a variety of comments to this question, some providing specific examples of useful research and management approaches, some highlighting specific actions they believe should be undertaken.
Research ♦ Undertake a combination of field and experimental approaches. Large scale experiments are needed to look at relevant effects ♦ Undertake field based projects e.g. Moira Lake drainage for carp control, trout eradication and use of natural waterfalls to restrict this species distribution ♦ Community based investigations are important for education but are not an effective means for research and investigation ♦ There needs to be a research/community partnership with effective community involvement and reporting to the community on results and implications of these results. A community based approach has been well received in Queensland ♦ Undertake biological research to determine species' attributes ♦ Determine the impacts on flow manipulation (including timing of wetland flooding, depth, duration, habitat aspects and physico-chemical parameters etc) on native and introduced species
Management ♦ Undertake education programs ♦ Improve habitat management ♦ Use an adaptive management approach concentrating on determining and reducing impacts rather than the number of fish ♦ Adopt pest management principles and recognise that introduced fish are vertebrate pests ♦ Provide for native fish spawning requirements e.g. environmental flows ♦ Use flow manipulation to inhibit recruitment of introduced species. For example, maintain natural flushing flows may limit gambusia since floods prevent them from breeding and feeding successfully ♦ Use riparian shading to inhibit introduced grasses. There is circumstantial evidence that loss of cover from predators and shelter from flows suppresses gambusia and guppies ♦ The National Management Strategy for Carp Control is an effective approach. The use of carp exclusion barriers, a field based approach, has the full support from the community
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♦ Initiate management plans for noxious fish species e.g. the recent Queensland publication 'Control of Exotic Pest Fishes: An Operational Strategy for Queensland Freshwaters' includes public education and rapid response to newly reported infestations ♦ A major obstacle that needs to be tackled is the preference of some parts of community to introduced species such as trout. Until there is agreement on the importance of biodiversity, there will be little support for control of trout ♦ Compel all states to declare carp, and possibly tilapia, noxious species ♦ Prevent koi carp from being promoted and distributed in some states ♦ Tighten up the management of the aquarium industry ♦ Ban all exotic species from outdoor ornamental ponds ♦ Provide breeding technology for suitable native species to use as alternatives for ornamental ponds ♦ Initiate much stricter and comprehensive monitoring of pet imports by people who can identify fish ♦ Establish heavier penalties for those contravening laws in relation to fish
Can you provide examples of research and/or management approaches that are not effective in addressing the issue of aquatic pest species and their management? Please indicate target species if appropriate.
Results: The comments provided concerning ineffective approaches related to control/harvesting of introduced species, management, education and community involvement.
Control/Harvesting The most frequent comments received related to whether there was value in harvesting introduced species: ♦ Community based eradication is not a conclusive way to study its effectiveness as a control technique ♦ Supporting industries based on carp may be economically useful but is no help at all as a control ♦ Commercial harvesting of any pest species is not a particularly useful control technique other than in extremely localised programs ♦ Targeted fishing for carp in open systems like rivers and large lakes is ineffective ♦ The use of rotenone in situations where colonisation can reoccur after poisoning is ineffective ♦ The use of screens to prevent interbasin transfers of introduced fish species is ineffective
Management Some respondents believed there was too much emphasis on species such as carp and trout. One argued that trout is managed as a recreational species although it causes significant damage to native species. Several respondents noted that there was no active management for many species. One argued that something should be done for species such as tilapia at an early stage of infestation. A respondent indicated that while penalties are severe in relation to noxious species in Queensland, there are examples of legal cases being lost on technical grounds. Another noted that manipulation of food webs is an ineffective approach.
Education/Community Involvement ♦ The effectiveness of community education is unknown
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♦ Public education has limited effectiveness particularly amongst ethnic communities who regard carp and tilapia as highly desirable given such species are part of traditional culture ♦ Community involvement is ineffective when it is only token and not realistically or well resourced
9. Education Are you aware of any educational material for school students, community groups and the broader community concerning aquatic pest species, their impacts on the environment and their management? If so, please provide details on material and comment on their effectiveness as educational tools.
Results: The most frequently received comments related to the recent educational strategy initiated by the Queensland Department of Primary Industries, which has used a multi-species approach. Material including posters and brochures of species such as carp and tilapia has been well received. Several noted that this information needs to be disseminated further and possibly to schools, pet stores, community groups, local government agencies etc. Another respondent indicated that it was too early to determine whether signs for tilapia had been effective although another indicated that these signs at boat ramps such as Tinaroo Dam are not being read because there are already too many signs. One respondent highlighted that an education module is due for release in July 2001. Displays at boat shows and media reports have been useful.
More general comments related to the effectiveness of: • using material such as small booklets to target the broader community within catchments • current affairs programs on television such as ABC Landline (e.g. for carp) particularly in country areas • talks and live fish displays • brochures, posters etc. developed by the National Carp Task Force for wide release across Australia. There is apparently constant demand for this material for students and the broader community
Several respondents indicated that educational material needs to: • target anglers concerning the detrimental impacts of unauthorised fish releases and the impacts of introduced fish on other aquatic fauna (e.g. genetic integrity etc). • be designed to get anglers on side and that this will not be achieved if managers call species such as trout a 'pest' • provide the right message to anglers and the broader community concerning species such as trout • identify that koi carp is a threat, that redfin can spread EHNV, and that using live bait fish is a threat • target higher secondary school level curriculum material, across Australia, given the apparent lack of information for school students • highlight the risks of translocating native species.
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5 Identifying Current and Potential Pest Plant Species
5.1 Identification Determining current and potential pest plant species in aquatic and riverine habitats over an extensive landscape such as the Murray-Darling Basin poses very real challenges. These come from the size of the Basin (which increases the area to be surveyed) and its biological heterogeneity (which makes stratified sampling a challenge); the relative sparseness of the population (which constrains sampling effort, and limits resources); the fact that a relatively large number of species are already established; the difficulty in determining which of the established species are actually pests; and the interaction of these factors. In addition, temporal changes are difficult to monitor, there having been no benchmark surveys done; and there are no look-up species lists on species ecology (does a species have an obligate or facultative relationship to water regime); and the long-thin shape of the riparian zone and the dynamic wet-dry character of many wetlands means that spatial extent and temporal variability present real obstacles to conventional or one-off survey approaches. Some of these are common to other aspects of riparian vegetation ecology (Roberts, in press).
In the absence of a better or more systematic approach, a questionnaire was used to (e-mailed to over 100 persons) to identify current and potential pest plant species, to establish the major management issues and to develop research ideas or themes relating to more effective management of pest plants in the Murray-Darling Basin. Results are given in Appendix 3. Low response rates from upland bio-regions and from South Australia mean that the findings reported below are not strictly representative of the Basin, but can certainly considered as probable trends.
Riparian habitats are known to have a high number (eg => 20%) of introduced species. Not surprisingly, a large number of plant species were identified as pests. However, as ecological significance increased so numbers declined and characteristics changed. Thus approximately 180 species were nominated as pests, of which 62 were considered significant pests, and 120 species were species of future concern. Focusing only on those species that were widespread (as determined by the percentage of stakeholders reporting), shows a similar same pattern of decreasing numbers and a shifting ecological focus. Thus the 23 species considered pests by 10% of respondents included a range of growth-forms and life-cycles and were mainly riparian and floodplain species (Table A2.1); the 16 species considered significant pests by at least 5% of respondents, included some aquatic macrophytes; only 12 species were future threats for at least 5% of respondents, and these were mostly aquatic macrophytes. Seven species were cited as increasers over the last 10 years (Question 9, Appendix 3).
Bio-regions proved to be a workable means of reviewing and over-viewing species distributions, but the low response rate for some parts of the Basin precluded any statistical comparisons of regional differences. However, north-south differences were evident for all types of species in lowland rivers and floodplains: pests, significant pests, and species of future concern.
Implications of such large numbers and of strong regional (and climatic) differences are:
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• Generic approaches to managing suites of species, rather than single-species management strategies, will need to be developed. • Single-species research projects will need wide or substantial support in order to proceed. Criteria for such support may need to be developed (if prototypes are not already in place) such as: wide distribution; large threat to biodiversity or to livelihood; threat to vulnerable or high profile habitats. Comparisons may be developed and priorities set using the AHP Weed Risk Assessment process (Section 2.1). • Research and investigations will need to target groups of species, with groups being formed to answer specific questions, based on plant functional types. Examples of specific questions are: habitat value of medium-sized understorey floodplain shrubs for native biota; flow-assisted dispersal of seeds, propagules and plant fragments.
Note that plant functional types may need to be derived de novo for each research question.
5.2 Management Issues Management issues were identified through answers to Questions 10 and 11. (Appendix 3)
People & Personnel: short experience of an operator in a given area; lack of expertise for working in potentially dangerous situations; role of the public Biological & Environmental attributes: large number and great diversity in target species; identification of relevant species; persistence Site characteristics: accessibility of riverine corridor; highly variable flow regimes and environments Strategic issues & Control options: constraints on use of ‘proven’ techniques using chemicals; early detections; full costing including alternatives costing; post-control activities; misplaced efforts Attitudes & Perspectives: Catchment perspective; inconsistencies between two sets of values may occur, with the potential for action paralysis;
These are standard issues for pest plant management. Considered individually, it is only Site Characteristics that are specifically relevant to aquatic and riverine environments or habitats. However, the proximity of the flowing environment and the importance of water as a resource means that most of these management issues have a specific challenge when placed in the riverine environment.
5.3 Research; Information & Education
RESEARCH The stakeholder survey (Appendix 3) identified 24 possible research projects and these were grouped into seven research areas, presented and discussed below.
[1] Potential. Knowing the likely eventual distribution and impact of particular species was suggested as an aid to resource managers seeking support for new pests and emerging weeds.
Depending on what scale this information is required and with what precision, this project could be answered by either simple maps (possibly based on bio-regions) or could require extensive research effort, as predicting the distribution and abundance of a species at a catchment-scale such as the Basin, is one of the
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 57 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire more challenging areas in plant ecology. Although appropriate spatial analyses and modelling approaches have become available over the last decade, predictive capacity is still challenged by issues of scale (catchment or micro-habitat), the availability of relevant species information (a challenge for species that are just becoming naturalised) and the role of anthropogenic disturbances (altered water regime, fertiliser, stock effects). These challenges are even greater in the riparian zone.
Understanding more about how information about eventual distribution might be used, by managers or researchers, would help to clarify the goals of a project on this topic.
A research project developing approaches to predicting likely distribution of a plant species in the riparian zones of the Basin could also consider the use of bio-regions as an intermediate scale between catchment and habitat. (The need for an intermediate geographic scale for representing information was the reason for using bio-regions in this scoping study.)
[2] New controls and control strategies: Research was suggested to develop new control techniques or control strategies, including biological controls, with an emphasis on efficiency and effectiveness and on targeting multiple species at once. None of the respondents appeared to be seeking a Magic Bullet.
There were several calls for new techniques or new strategies, implying that conventional approaches and current controls are either ineffective in aquatic and riparian habitats or ineffective on aquatic or riparian pest plants. These calls are responding to two developing threads: the need to find alternatives to the use of chemicals (raised as a management issue, Section 5.2, Appendix 3), which have in the past been a ‘reliable’ type of control agent for certain aquatic macrophytes and some woody riparian species; and the ever- increasing numbers of species that are becoming naturalised.
A single research project is unlikely to produce answers. Instead, more strategic approaches are needed over a range of time-horizons; as well as general support for projects evaluating biological controls (Project 17, Section 7.4.17). The strategic approaches may need to combine control with prevention plus more informed priority-setting (eg take a habitat focus rather than a species focus), always with the characteristics and distinctiveness of the riparian and aquatic environments as context. Mapping out strategic approaches is the function of major research institutions. The danger here is that the relevant knowledge areas (weeds, controls and prediction versus riverine and floodplain processes) are dispersed across different institutions, making them harder to bring together.
There are several ways forward for MDBC to respond to this suggested area of research. Improved linkages and more formal connections with organisations and agencies undertaking relevant weed research; Development of a position-statement, outlining relevant research, the organisations responsible, statutory responsibilities; Support research and investigation programs already under way or planned; Taking the lead in characterising the research and management issues for aquatic and riparian pest plants by a targeted workshop.
[3] Single species projects: Seven species were identified as subjects for single-species research projects, with topics suggested ranging from integrated control to basic biology/ecology and impact assessment. 58 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire
Not all these seven species merit individual research projects. An overview of their relative importance (Table 9) based on findings of answers to questionnaire (Appendix 3) shows that the two native species, cumbungi and Common Reed Phragmites australis, are not of species of major concern to stakeholders in the Basin, by any of the four criteria; moreover as these are both native species they are outside the definition of pest as used here (Section 1.3). Problems due to these two plants, both tall emergent macrophytes, are likely (pers. obs. Jane Roberts) to be the result of altered water regime, so these could be candidate species for investigations into better water management, e.g. project 18 “Assessment of the effectiveness of habitat restoration as a means of controlling biological invasions” (Section 7.4.18). Parrot’s feather Myriophyllum aquaticum, although not widely recognised as a problem species (Table 9), can be considered as one that is a potential threat, making it a candidate species for research projects targeting issues to do with emerging weeds, such as early detection or rapid response, or generic issues such as the role of hydrology in propagule or fragment dispersal.
[4] Restoration issues: Restoration issues identified by stakeholders were limited to ensuring that control programs for controlling and removing woody pests in the riparian zone were followed by appropriate planting programs. This highlights one of the difficulties faced by resource managers, of being funded for short-term high-profile projects (eg removal of willows) but not necessarily for the follow-up work that will ensure a good return on expenditure.
Table 9: Stakeholders' assessment of seven species nominated for single species research Species Pest Significant Potential Increaser Pest Threat Arrowhead Sagittaria graminea √ √ Lippia Phyla canescens √√√√√√√√√√ Water hyacinth Eichhornia crassipes √√√√ Cumbungi Typha spp Common Reed Phragmites australis Alligator Weed Alternanthera philoxeroides √√√√√√√ Parrot’s feather Myriophyllum aquaticum √ Key: Pest = Recognised as a pest by 20% respondents. Question 6, Table A2.1 Significant pest = Recognised as a pest by at least 10% of respondents. Question 6, Table A2.3 Potential threat = Recognised as a pest. Question 7, Table A2.5 Increaser = An expanding species. Question 9 Three of these, Arrowhead Water hyacinth and Alligator Weed, were included in the trial application of the AHP WRA process (Section 2.1) which gave them a rank of 8th, 1st and 4th respectively, and a status of High priority and Very High priority (Table 5).
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[5] Riparian zone (grazing). Riparian zones exposed to long history of sustained or high intensity grazing are known to undergo major structural changes due to shift in species composition. Three respondents took a more positive view of grazing in the riparian zone, seeking ways of using stock grazing in combination with flooding patterns to improve biodiversity of the riparian zone, without loss of amenity value. This is a large research topic, requiring both generic knowledge and regionally-specific answers, and some of these are already being provided by a project at Charles Sturt University, Wagga Wagga. The implementation of these ideas, if found to be feasible, will contribute greatly to fostering new approaches, as sought by stakeholders (above: [2] New controls and new strategies).
[6] Evaluation. Formal documentation and evaluation of weed control operations was suggested as an essential part of effective pest plant management. Whilst this may not be necessary for experienced operators who have developed good understanding of the reasons for success or failures, it could be an essential short-cut for persons new to pest plant management. It could also prove valuable background for scoping means of improving techniques.
[7] Scientific Knowledge. Four topics fell in this category, all concerned with generic understanding and long-term knowledge and its application: the use of introduced plants by native biota; tolerance of floodplain weeds to increasing salinity; development of a weed classification system; ecology-flow relationships.
INFORMATION AND EDUCATION The last part of the stakeholder survey sought to establish what products and resource materials were most used and valued by respondents, what educational materials were being used, and what were information needs. This returned useful comments but was probably the least successful part of the questionnaire.
Useful and valued resources: Respondents used a range of printed and published materials, from leaflets and pamphlets to reference books. Web materials were mentioned rarely and information sources such as CD-ROMs were not mentioned at all. A number of factors could account for this bias towards printed and published materials: lack of PC access or lack of familiarity with PC-based material; the need to use materials that can be readily taken in to the field, or easily shared with other field workers; resistance to modern media; preference for reliable reference sources; content, suitability and quality of printed and published material compared with other forms of information; questions or phrasing used in the survey were preferentially linked to printed materials.
Reasons for this bias would need to be established prior to investing in a Web-based to pest plant program, such as certain elements in the Education program outlined above.
5.4 Building on the Questionnaire The results of the stakeholder survey reported above and detailed in Appendix 3 have been used to set priorities and topics for research and investigation.
Selecting Target Species: Research topics on pest plants that were suitable for development as project briefs were identified through interactions with researchers, consideration of current research programs (mainly CRC Weed Management Systems, CRC Freshwater Ecology to lesser extent), through team discussions and 60 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Questionnaire by stakeholder survey. For example, stakeholders suggested seven species as subjects of single-species research projects but on consideration this was reduced to just four possibilities (Section 5.3): water hyacinth Eichhornia crassipes; arrowhead Sagittaria graminea; lippia Phyla canescens; alligator weed Alternanthera philoxeroides. All four of these are significant for stakeholders (Table 9), but lippia Phyla canescens has two attributes that make it a strong candidate for resourcing as a single-species study: • There is little likelihood of tapping into overseas information, as lippia is not widely accepted as a pest plant in other countries, with the exception of southern France. • It is both an economic and an environmental weed.
Additional research projects: Other research topics that could be developed as research projects are:
[1] Propagule dispersal and water management. There is a widespread assumption that aquatic and riparian plants, including pest plants, are dispersed by water (Appendix 3, Question 8), although there is little documentation of this and little understanding of the relative importance of major flow events (floods) versus in-channel flows. The implications of flow-assisted dispersal are that serious aquatic weeds of irrigation areas or urbanised area have the potential to reach natural riverine ecosystems. It is not known if: seeding the natural environment by propagules or fragments does occur; how long propagule is viability (ie how far downstream does a threat extend); whether there are specific types of propagules or fragments that represent a greater risk; whether any risk can be mitigated by different water management practices upstream. The development of a dispersal model, initially as a conceptual model addressing these questions, could explore this. The model could be tested against pest plants that are known to be expanding (Appendix 3, Question 9), in particular Arrowhead Sagittaria graminea.
Generic work using a number of species including Arrowhead would complement add to contemporary work on Sagittaria graminea in northern Victoria. [2] Evaluation of current control practices.
[3] Riparian pest plants and native biota. In certain plant communities, pest plants can be valuable habitat for native biota: if thorny they may offer protection against predators; or they may be the only suitable structural feature available in a particular community or near appropriate food sources. Removal of riparian pest plants, which may be required of landholders by law if a species is noxious, certainly addresses issues such as plant bio-diversity and functional integrity of the riparian zone but could adversely affect dependent biota and thus have inadvertent negative consequences for conservation. Clearly it is impossible to review habitat requirements of all biota prior to undertaking a pest plant control program. What is required are: ecologically-sound guidelines to recognise situations where such dependency is likely; a literature review focusing on vulnerable target groups, such as woodland birds. Protocols for assessing riparian habitats are available (Jansen and Robertson 2001) and could be used and extended in relation to riparian habitat. Lowland reaches are more degraded so may be a priority.
[4] Bio-regions. The usefulness of bio-regions to define management units and to map species distribution.
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6 Species’ Profiles Detailed species profiles were prepared for nineteen current and potential pest species within the MDB. These nineteen species were chosen for reasons specific to each group (fish, invertebrates, plants) as outlined below and may be considered as a possible information template. The nineteen species comprise 13 fish, 4 invertebrates and 2 plants.
The purpose of the species profiles is to provide an overview of each individual species within the Murray- Darling Basin, so information is presented on current distribution and abundance, biology and ecology, existing knowledge of environmental impacts and methods of control. These profiles provide some indication of species of current and potential concern within the MDB. This does not however represent a comprehensive review of all species which may cause detrimental impacts within the Basin. Further investigation is required, in association with a risk assessment procedure to clarify those priority species that should be the subject of research and management.
Fish Species Profiles were prepared for 13 fish species. These were chosen taking into consideration existing information from relevant literature and the view of experts, including from the results of the fauna questionnaire, as well as species highlighted within the following reviews: The State of the Environment Report (Clarke et al. 2000), Arthington and Bluhdorn (1995) and Arthington and McKenzie (1997). The fish species are placed in the order of significance identified by respondents in the questionnaire (Section 4).
Invertebrates The four species chosen reveal the range of ecological and management issues associated with invertebrate pests, and also show how these differ from vertebrate pests, and from plants. All four are considered potentially significant.
Plants The number of plant species that could be profiled is high, probably several hundred (Roberts, in press). As profiles of most of these are already available in various weed books and through Web sites such as Weeds of National Significance, the selection here was limited to two taxa: lippia Phyla canescens and willows Salix spp. Unlike many of the species identified as current and potential threats in the Pest Plant Questionnaire (Section 5 and Appendix 3), these are both strongly associated with riverine habitats: floodplain, water courses and weirpools. Moreover, at least in the lowland reaches, the distribution of both these is associated with regionally and locally altered water regimes.
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6.1 Fish
6.1.1: Cyprinus carpio (Carp)
Figure 10: The distribution of Carp Cyprinus carpio in the MDB Sources: Cadwallader 1996; McDowall 1996; Clarke et al. 2000; Koehn et al. 2000
Overview Carp are the most widely distributed fish species in the world (Clarke et al. 2000). They are native to China and have subsequently spread throughout Asia, Europe and North America. Fossil records exist in Africa, India and south-east Asia (Koehn et al. 2000). They were introduced into most countries as a source of food and for ornamental purposes (Brown 1987). Carp were first imported into Australia during the 1860s (Shearer and Mulley 1978), and are now found throughout the entire MDB (Clarke et al. 2000).
In Australia, carp are becoming a popular angling species but there is a widespread perception that they have poor eating qualities due to the abundance of small bones and a muddy taste. However, carp are becoming a commercially viable option because of the recent termination of commercial fishing licences for native finfish in New South Wales. Currently, carp are used in specialised dishes for human consumption, craybait, pet food, export, fertiliser and stock supplements (Koehn et al. 2000).
The impacts of carp include economic, environmental and aesthetic factors. Industries that are affected include water suppliers for domestic and industrial users, agriculture, commercial and recreational fisheries and tourism (Koehn et al. 2000). Environmental impacts include; decreased water quality, increased stream bank erosion and phytoplankton concentrations, decreased abundance and diversity of macrophytes and macroinvertebrates, and competition with native fish for food and habitat (Koehn et al. 2000).
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Current Distribution and Abundance There are three different strains; Yanko, Boolara and Prospect (Shearer and Mulley 1978, Arthington and McKenzie 1997). Rapid expansion of carp throughout the MDB only began after the release of the Boolara strain into the Murray River at Mildura in 1964 (Shearer and Mulley 1978). Thereafter the range of carp underwent rapid expansion through the MDB between 1974 and 1976 with the aid of a series of floods. They were subsequently found in the rivers of Queensland (Grant 1982). Carp are now found in the Warrego River in Queensland, south to the Murray River mouth, including most rivers in the MDB. They also occur in many coastal streams in Victoria, NSW, Queensland and South Australia, and in the south of Western Australia. Carp also occur in Lakes Crescent and Sorell in Tasmania (Kailola et al. 1993, Clarke et al. 2000). Surveys conducted by New South Wales and Victorian Fisheries in 1994-95 revealed that carp make up as much as 80% of the total fish biomass in the MDB, and as high as 96% for some river stretches (Roberts and Tilzey 1997). In south-eastern Australian, carp are established in many rivers and associated waters, anabranches, billabongs, backwaters and floodplains (Koehn et al. 2000).
Biology and Ecology Carp are a member of the Cyprinidae family and are often confused with their close relative goldfish. Carp are ecological generalists that inhabit a variety of habitats, typically mid to low altitude areas of freshwater rivers, lakes and billabongs. They have also been observed in estuarine environments (I. Stuart NRE pers. obs.). Carp are most active during the night and are gregarious, although very young and very old fish are solitary (Cadwallader and Backhouse 1983). Carp prefer warm slow flowing waters with a silty substrate that enables then to forage for food. However, they are able to tolerate extreme environmental conditions such as high and low water temperatures and low oxygen concentrations (Clarke et al. 2000). Furthermore, during winter carp form shoals of up to 100 fish and enter a state of dormancy (Cadwallader and Backhouse 1983).
Male carp mature between 2-3 years of age, while females between 3-4 (Brown 1987). Carp spawning starts as early as late winter and can continue through until summer (Stuart and Jones 2001). Spawning of carp occurs between 15-250C with multiple spawning events possible in the one year (Swee and McCrimmon 1966, Crivelli 1981, Kailola et al. 1993). Carp are highly migratory and will travel in excess of 200 km to reach their spawning grounds (Stuart and Jones 2001). Spawning grounds consist of slow flowing heavily vegetated floodplains with warm water temperatures (Koehn et al. 2000). Two to three males usually accompany each female during courtship, with each female capable of producing 100 000 eggs per 0.9 kg of body weight (Kailola et al. 1993). The eggs are small (1.5 mm diameter) and are adhesive once in contact with the water (Cadwallader and Backhouse 1983). The eggs take 2-8 days to hatch depending on water temperature, with newly hatched fish being 4-6 mm long (Cadwallader and Backhouse 1983).
Adult carp are opportunistic omnivores taking anything from microscopic algae to a variety of animal materials: insects, molluscs, crustaceans and macroinvertebrates. Juvenile carp feed solely on zooplankton (Cadwallader and Backhouse 1983, Clarke et al. 2000). Carp forage for food by ingesting silty substrate layers and filtering out any organic particles greater than 0.5 mm with their pharyngeal sieve (Koehn et al 2000). The growth of carp in Australia is highly variable and is dependent upon water temperature and food availability. Fish up to 10 kg are relatively common, however, most carp are between 0.5 and 5 kg (Koehn et al. 2000).
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Environmental Impacts Carp inflict environmental and economical impacts on both the private and public sectors by reducing water quality and degrading aquatic habitats (Koehn et al. 2000). As the Government owns most waters any remedial works or control program costs are usually born by the Government, or passed onto water users (Koehn et al. 2000). The impacts to industry include; increasing the costs of domestic and irrigation water supplies for agriculture, recreational fisheries, commercial fisheries and tourism (Koehn et al. 2000). Environmental impacts include increasing turbidity, stream bank erosion, nutrient concentration and phytoplankton concentrations, while decreasing the diversity and abundance of macrophytes and macroinvertebrates, and competing with native fish for food and habitat (Koehn et al. 2000).
Although the impacts of carp on the environment and public and private sectors are well documented, the amount solely attributed to carp cannot be calculated. Confounding factors such as changes in flow regime, construction of dams/barriers, changes in water temperature, desnagging of rivers, and loss of riparian habitat have all contributed. Furthermore, carp provide food for piscatorial native fish such as golden perch (Macquaria ambigua), Murray cod (Maccullochella peelii peelii), water rats and birds (Kailola et al. 1993).
Methods of Control In the past, attempts to control carp have been usually been conducted by State and Territory agencies (Koehn et al. 2000). Control methods include: capture and removal by professional and amateur fisherman; environmental manipulation, such as changing flooding regimes to trap adult and juvenile carp on the spawning floodplains (Koehn et al. 2000). Furthermore, manipulating (Biomanipulation) the relationships between plants, animals, and the environment, can possibly reduce carp numbers (Koehn et al. 2000). For example, by increasing the number of predatory fish present in the system, the number of carp reaching adulthood is possibly reduced (Koehn et al. 2000). Similarly, Harris (1997) suggests that environmental rehabilitation of existing waterways could potentially impose an indirect form of carp control, as environmental disturbance is recognised as favouring the establishment of exotic species. In addition, biological controls such as viral control agents (Spring Viraemia of Carp Virus) and immunocontraception, or the introduction of a sterility gene, have also been suggested, however these are still in the development phase (Ron Thresher, CSIRO, pers. comm.).
Integrated control is the most likely strategy to be adopted to control carp, as no one method is likely to be 100% successful in all environmental conditions. Existing control methods are relatively inexpensive on a small scale, however they soon become too expensive and time consuming when the whole MDB is considered. Application of poisons such as rotenone have been used to control carp in small enclosed systems, however chemicals are not species specific and kill all fish and macroinvertebrate species in the water column. Carp exclusion devices, such as barriers to movement into billabongs and wetlands have also been used successfully throughout Australia to reduce the size class and number of carp (Stuart and Jones 2001).
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6.1.2: Gambusia holbrooki (Eastern Gambusia)
Figure 11: The distribution of Gambusia Gambusia holbrooki in the MDB Sources: Cadwallader 1996; Clarke et al. 2000; Davies and McDowall 1996
Overview Gambusia are native to the southern United States of America and northern Mexico. The native range of G. holbrooki is the area from central Alabama east into Florida and throughout the Atlantic coastal drainages to New Jersey (Rivas 1963, Wooten et al. 1998). The name gambusia is derived from the Cuban word “gambusino” which means “nothing”, or “something worthless” (Krumholz 1948, Lloyd 1990, Serventy and Raymond 1980). The only species of gambusia present in Australia is Gambusia holbrooki (Lloyd and Tomasov 1985, Lloyd 1990a).
Eastern gambusia were first introduced into Australia from Georgia (U.S.A.) via Italian stocks in 1925, to control mosquitoes, and were released into the Botanical Gardens in Sydney (Wilson 1960; Bayly and Williams 1973; McKay 1984; Myers 1965). In 1926 the Chief Health Inspector of the City of Sydney established wild populations from the specimens imported from Italy (Clarke et al. 2000; Wilson 1960). In 1940 eastern gambusia were flown to Darwin, and during World War II were spread through military camps in many parts of Australia (Myers 1965). Eastern gambusia have since been introduced to other parts of Mexico and the USA (including Hawaii) outside of their native range. They have also been introduced into Canada, Puerto Rico, New Zealand and other Islands throughout the Pacific including the Mariana Islands, Micronesia, Guam, the Line Islands, French Polynesia, American Samoa and Western Samoa (Maciolek 1984).
The major dispersal agent of eastern gambusia are humans, either directly or indirectly or through floods and irrigation channels. In Australia, eastern gambusia are found in at least eight drainage divisions (Merrick and Schmida, 1984).
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Current Distribution and Abundance Eastern gambusia are widespread and common throughout New South Wales, South Australia and Victoria in both inland and coastal drainages (McKay et al 2001). They are also common in the coastal drainages of Queensland, parts of Western Australia and the Northern Territory. There are no known populations in Tasmania (McDowall 1996, Allen 1989, Arthington et al. 1999). Gambusia occur in almost every aquatic habitat in south-eastern Australia except for the tableland streams where winter temperatures affect their reproductive cycle (Clarke et al. 2000).
Eastern gambusia have recently been eradicated from a swamp and small “goldfish” ponds on residential properties around Alice Springs in the Northern Territory. These accounts represent the only records of eastern gambusia in the Northern Territory in the last 30 years (Robbie Henderson, Waterwatch, pers. comm.). A similar control program occurred in a backyard dam in Tasmania in the early 1990s and since then there have been no reports of eastern gambusia in Tasmania (Brett Mawbey, Inland Fisheries Service, Tasmania, pers. comm.).
Biology and Ecology Eastern gambusia are abundant in warm slow flowing or still waters amongst aquatic vegetation at the edge of waterbodies in water depths of 10 cm or less (Merrick and Schmida 1984; McDowall 1996; Faragher and Lintermans 1997; Arthington et al. 1999). Eastern gambusia show a thermal preference for water of 31°C but are able to withstand wide temperature ranges from just above freezing (0.5°C) to 38°C (Lloyd 1984, Lloyd 1986). Eastern gambusia have the ability to tolerate low dissolved oxygen concentrations and are able to utilise oxygen-rich surface layers of water (Lloyd 1984). They are also tolerant of a wide range of salinities from pure fresh water to fully marine (McDowall 1996). Eastern gambusia tolerate a pH range between 4.46 to at least 10.2 in laboratory conditions (Swanson et al. 1996).
Eastern gambusia have been able to invade a wide range of habitats including turbid, silty lower reaches of rivers, swamps, lakes, billabongs, thermal springs, salt lakes, the cooling pondage of a power station and ornamental ponds of many urban parks (Lloyd 1984, Lloyd et al. 1986, Cadwallader and Backhouse 1983). Undisturbed lotic systems with naturally variable discharge regimes are not favoured by eastern gambusia, with high river discharges almost eliminating populations (Arthington et al. 1990, Galat and Robertson 1992, Meffe 1984). Eastern gambusia have a remarkable ability to withstand adverse conditions, sometimes far outside their normal tolerances.
Females are much larger and deeper bodied than males reaching maximum standard lengths of 60 mm and 35 mm respectively (McDowall 1996; Cadwallader and Backhouse 1983). Eastern gambusia grow rapidly, becoming sexually mature in under two months (McDowall 1996). Eastern gambusia are a live bearer (i.e. viviparous), with fertilisation occurring internally and the embryos developing within the female (McDowall 1996; Cadwallader and Backhouse 1983). Females have an average of two or three broods per season, and store sperm from breeding season to breeding season (Lund 1999a; Howe 1995). Sexually mature females have been recorded as having up to nine broods a year from about August to April. The gestation period is between 21 and 28 days, with about 50 young being produced on average, though this may exceed 100, with more than 300 having been reported in a single brood (Cadwallader and Backhouse 1983; McDowall, 1996; Milton and Arthington 1983). In small ponds a population of 7000 gambusia have been known to increase to over 100 000 fish in five months despite natural mortalities (Lloyd 1984). 68 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Eastern gambusia are an opportunistic omnivore and feed on a diverse range of terrestrial insects such as ants and flies that fall on the water’s surface, as well as aquatic invertebrates including bugs, beetles and also zooplankton (Arthington 1989, McDowall 1996, Lloyd 1986). Gambusia are an adaptable generalist predator, able to vary their diet with the fauna available (McDowall 1996). Australian studies indicate that gambusia are a poor mosquito predator, with mosquitoes only making up a small part of their diet (Lloyd 1984, Lloyd 1986).
Environmental Impacts Introduced species often occur in degraded environments and it is difficult to separate their impact on native fish and amphibian species from that of other variables. Eastern gambusia have wide environmental tolerances, potential for rapid increases in numbers due to being a livebearer, omnivorous diet and aggressive nature. Many of these characteristics make it likely to impact on a range of native fish and amphibian species. Impacts may include competition for resources such as food and space, and predation of eggs, larvae and juveniles of native fish and amphibian species.
Impacts Impacts on Fish Species Belk and Lydeard (1994) noted that while eastern gambusia are considered to significantly affect populations of small native fish, the process is not clear and may include both predation and competition. The indirect impacts of gambusia, such as disturbance to ecosystems is less clear. Some 35 fish species worldwide have declined in abundance or range as a result of interactions with gambusia (Lloyd 1990). Myers (1965) argued that in most areas where gambusia has been introduced it tends to gradually destroy most or all of the smaller native fish species which prey on mosquitoes, and that it was also likely to have had a significant impact on the young of larger species of fish. In Australia no local extinctions of fish species have been attributed to eastern gambusia but they are thought to have played a role in the decline of fish species from six genera: Mogurnda, Ambassis, Melanotaenia, Pseudomugil, Craterocephalus and Retropinna (Lloyd 1990). Much of the evidence is however circumstantial and patchy. There are some evidence of predation and interference competition by eastern gambusia on native fish species.
Eastern gambusia can exhibit aggressive behaviour towards other fish, including those much larger than themselves, which includes harassment such as chasing and fin-nipping. Experiments under captive conditions have shown eastern gambusia to exhibit aggressive behaviour towards ornate rainbowfish (Rhadinocentrus ornatus), Duboulay’s rainbowfish (Melanotaenia duboulayi), firetailed gudgeon (Hypseleotris galii) and southern blue-eye (Pseudomugil signifer) (Jamie Knight, NSW Fisheries, pers. comm.). The Action Plan for Australian Freshwater Fishes (Wager and Jackson 1993) notes that impacts of eastern gambusia, including predation, competition for food and habitat and aggression, have been confirmed for: Oxleyan pygmy perch (Nannoperca oxleyana) and southern purple-spotted gudgeon (Mogurnda adspersa) and remains speculative for: red-finned blue eye (Scaturiginichthys vermeilipinnis), Ewen’s pygmy perch (Nannoperca variegata), dwarf galaxias (Galaxiella pusilla), Yarra pygmy perch (Edelia obscura) and honey blue-eye (Pseudomugil mellis).
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Impacts on native amphibian species Concerns for the role of eastern gambusia in the decline of amphibian species, particularly members of the Littoria aurea complex have been expressed by several authors. However, evidence is limited, due in part to conflicting findings and methodological limitations of some studies (McKay et al. 2001).
Impacts on native macroinvertebrate species There is some evidence that eastern gambusia can cause reductions in macroinvertebrates such as rotifers, cladocerans, ostracods, copepods, mayflies, dragonflies, molluscs and beetles (Hurlbert et al. 1972, Lloyd 1990a, Lund 1999b). Eastern gambusia may change macroinvertebrate assemblages by differential predation, which can make a system unstable, and may cause an increase in phytoplankton populations (Lloyd 1984, Lloyd 1990a).
Methods of Control There have been very few documented control programs specifically targeted at eastern gambusia recorded to date, due mainly to the absence of control methods which are both effective and specific for eastern gambusia (McKay et al. 2001). The recent control of gambusia in the Northern Territory demonstrates the potential for effective management when such a species has a highly restricted distribution. A concerted effort was made to control the spread of this species through the drying out of the swamp and by poisoning the ponds with a piscicide (rotenone) (Robbie Henderson, Waterwatch, pers. comm.). Eastern gambusia released into a farm dam in Tasmania in the early 1990s were quickly located, identified and promptly poisoned with rotenone.
The use of predatory fish species, pathogens and parasites, viruses, chemicals, rotenone, lime, physical control (e.g. electrofishing, netting, trapping), environmental rehabilitation or manipulation have been suggested as possible control methods. Also the use of molecular biology and biotechnology to produce immunocontraceptives or artificially enhanced pathogens that either kill or disable target species via the blocking of reproductive mechanisms has been suggested as a possible control method (McKay et al. 2001). However, despite it being likely that this method would require considerable effort and resources to establish, it may well be the only area with real potential for properly controlling a species such as eastern gambusia.
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6.1.3: Carassius auratus (Goldfish)
Figure 12: The distribution of Goldfish Carassius auratus in the MDB Sources: Cadwallader and Backhouse 1983, Clarke et al. 2000.
Overview Goldfish are native to China, Taiwan, southern Manchuria, Korea, Japan and Hainan (Clarke et al. 2000). They are introduced into many countries including: New Zealand, Australia, Canada, USA including Hawaii, Puerto Rico and Western Somoa (Maciolek 1984). Goldfish have achieved almost worldwide distribution through the ornamental trade (Brumley 1996), and were first introduced in to Australia in 1876 (Arthington and Bluhdorn 1995). They are now found in Western Australia, South Australia, Victoria, New South Wales, Queensland and Tasmania.
Goldfish are considered to be a poor angling species and are widely thought uneatable because of their bone structure and muddy taste (Grant 1982, Arthington and Bludhorn 1995). Goldfish are closely related to carp, and readily hybridise with strains found in Australia (Clarke et al. 2000). They have little economic value outside the aquarium trade, and are usually sold as craybait when captured by commercial fisherman (Clarke et al. 2000).
The impacts of goldfish on freshwater biota are not well understood in Australia. However, because of its ability to hybridise with carp their effects are thought to be similar (Hume et al. 1983, Arthington and Bluhdorn 1995). Goldfish carry the bacteria Aeromonas salmonidica, which cause bleeding ulcers on their skin (Clarke et al. 2000). This disease has the potential to devastate the cultured salmonid industry (Whittington and Cullis 1988).
Current Distribution and Abundance Goldfish are possibly the most widely distributed freshwater fish in Australia (Brumley 1996, Arthington and McKenzie 1997). They are found in rivers from Fitzroy river in central Queensland, throughout South Australia to the south-west of Western Australia (Kailola et al. 1993), in most parts of New South Wales and A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 71 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Victoria, as well as many coastal streams, the MDB and the Cooper creek system (Brumley 1996). Like carp, they are found in greatest abundances throughout the MDB, and are more abundant than native species in Victoria (Arthington and McKenzie 1997). Fast flowing water appears to be the only factor limiting goldfish's movement into the high country (Weatherley 1967).
Biology and Ecology Although they belong to the same family as carp, Cyprinidae, goldfish differ in a number morphological features. The most obvious are the absence of barbels, a shorter deeper body, large eyes, and olive bronze colouration (Brumley 1996). Like carp, goldfish are ecological generalists capable of living and adapting to almost any environmental conditions (Clarke et al. 2000). Their preferred habitat is still and sluggish waters and they are capable of surviving in relatively high water temperatures and low oxygen concentrations (Brumley 1996, Clarke et al. 2000). In addition, goldfish have the potential to become one of the most genetically vigorous species in inland freshwaters because of the continued release of fish with different genetic makeup (Clarke et al. 2000).
The breeding season is between October and January when water temperatures exceed 150C (Merrick and Schmida 1984, Arthington and Bluhdorn 1995). Sexual maturity is reached between 3-4 years of age, but can occur during their first year (Cadwallader and Backhouse1983). Goldfish produce 100 000 eggs per 0.9 kg of fish that are spawned in batches (Kailola et al. 1993). The eggs are 1-1.5 mm in diameter, adhesive, and are laid among aquatic plants and submerged objects (Cadwallader and Backhouse1983, Merrick and Schmida 1984). After spawning the eggs take 5-7 days to hatch depending on temperature. Young larvae attach themselves to solid substrates to absorb their yolk sac (Brumley 1996).
Goldfish are relatively long-lived and specimens in South Australia have been aged at 10 years and reaching 344 mm in length (Cadwallader and Backhouse 1983, Merrick and Schmida 1984). Growth rate of goldfish is variable and depends on water temperature, and the availability of food and habitat. Lengths of 44 - 178, 76 - 233 and 101 - 257 mm were achieved at the end of their first, second and third years respectively (Cadwallader and Backhouse 1983).
Juvenile goldfish feed on plankton, while adult goldfish are omnivorous and feed on a variety of plant materials, algae, detritus and small aquatic insects and macroinvertebrates (Cadwallader and Backhouse 1983). Goldfish serve as a source of food for piscivorous native fish such as Murray cod, trout cod and golden perch.
Environmental Impacts The impacts of goldfish on the environment and other flora and fauna are not well understood in Australia. However, because of its ability to hybridise with carp their effects are thought to be similar (Hume et al. 1983, Arthington and Bluhdorn 1995). They include factors such as competing for food and habitat and increasing water turbidity (Brumley 1996). In addition, Wager and Jackson (1993) suggest that the decline of trout cod is a result of their interaction with goldfish, and may have also introduced the goldfish ulcer disease (Aeromonas salmonica) into Australia through infected individuals (Arthington and Bluhdorn 1995). The disease is highly pathogenic to Salmonid species and so is prohibited from entering Tasmania (Kailola et al 1993).
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Methods of Control Similar control techniques to control carp can be used for goldfish given that goldfish have to ability to hybridise with carp, have similar feeding strategies and have the same distribution. Preventing the spread of goldfish should be centred on the aquarium trade given that much of their range expansion is attributed to aquarium releases and their use as live bait (Arthington and Bluhdorn 1995). Furthermore, with the introduction of more goldfish into Australia through the aquarium trade, the chance of importing a highly infectious disease is increased (Clarke et al. 2000).
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6.1.4: Perca fluviatilis (Redfin)
Figure 13: The distribution of Redfin Perca fluviatilis in the MDB Source: Cadwallader 1996; Clarke et al. 2000; McDowall 1996
Overview Redfin are native to Europe and Asia, with the exception of Spain, southern Italy and Greece (Clarke et al. 2000). They are also established in New Zealand and South Africa (Cadwallader and Backhouse 1983). Redfin were first introduced into Tasmania in 1862 for recreational fishing purposes (Merrick and Schmida 1984); they were the first freshwater fish successfully introduced into Australia (Bayly and Williams 1973). In 1868 they were introduced into Victoria (Merrick and Schmida 1984), and in 1888 were distributed throughout New South Wales. They are now found in Victoria, New South Wales, South Australia, Western Australia and Tasmania (Clarke et al. 2000).
Redfin are a popular game fish that provide good angling opportunities. In Europe they form an important commercial fishery with up to 30 000 tonnes being captured annually, however in Victoria and South Australia, they form the basis of a small commercial fishery (Cadwallader and Backhouse 1983, Clarke et al. 2000).
Redfin are piscivorous by nature, with anecdotal evidence suggesting they have a major impact on native fish communities (Arthington and Bludhorn 1995). Their tendency to form large shoals has detrimental effects on native fish through direct predation and competition for food and habitat resources (Cadwallader and Backhouse 1983).
Current Distribution and Abundance Redfin are currently distributed throughout western Victoria, southern New South Wales, the Australian Capital Territory, Tasmania, and the south-west corner of Western Australia (Arthington and Bluhdorn 74 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
1995). Redfin are found throughout the southern half of the MDB and throughout the Border Rivers Basins in northern New South Wales and southern Queensland (Clarke et al. 2000). Floods have aided the distribution of redfin throughout the Murray-Darling, while their range has been extended greatly throughout Victoria because of hatchery production (Cadwallader and Backhouse 1983). They are considered to be common in their range, and often locally abundant (Cadwallader and Backhouse 1983, Clarke et al. 2000). High water temperature (310C), fast flowing water (Merrick and Schmida 1984, Clarke et al. 2000) and their sedentary nature (Cadwallader and Backhouse 1983) limit their distribution.
Biology and Ecology Redfin inhabit a variety of habitats including: billabongs, dams, lakes rivers and smaller streams. They prefer areas with aquatic vegetation, rocky outcrops and woody debris, and are restricted by steep gradients and high water velocities (Cadwallader and Backhouse 1983). Redfin are tolerant of high salinities (up to 50% seawater), however, they are rarely found in brackish water (Cadwallader and Backhouse 1983). Redfin reach maturity rapidly, becoming sexual maturity in their first year (Clarke et al. 2000). Females carry approximately 100 000 eggs per kg of fish, and are all released in one event (Clarke et al. 2000). Spawning usually occurs during the night with several males chasing individual females. Eggs are layed in long ribbons, over aquatic vegetation and woody debris. The egg 'ribbons' can be up to three metres in length and consist of gelatinous substance with numerous openings to allow water to circulate (Cadwallader and Backhouse 1983, Clarke et al. 2000). Hatching time is temperature dependent, and can vary from 7 days to 3 weeks. Furthermore, young redfin form shoals for some time before becoming solitary (McDowall 1996).
Growth of redfin varies with water temperature, turbidity, population density and the availability of quality food (Cadwallader and Backhouse 1983). Redfin can grow to reach 600 mm in length and 10.4 kg in weight, but are more commonly 1-3 kg (Cadwallader and Backhouse 1983). In New Zealand they have been known to reach 110 mm in length in the first year, and 160 mm in their second (Merrick and Schmida 1984).
Juvenile redfin feed on small invertebrates, particularly copepods and cladocerans and small macro- invertebrates, while adults feed on larger macro-invertebrates such as shrimps, yabbies, molluscs, crayfish as well as other fish (Cadwallader and Backhouse 1983, McDowall 1996).
Environmental Impacts It is generally agreed that because of redfin's predatory nature and prolific breeding habits they have an adverse effect on native fish (Cadwallader and Backhouse 1983). Redfin may compete with larger native fish such as; Murray cod, golden perch, silver perch, Macquarie perch and trout cod for food and habitat, and in doing so potentially affecting their abundance and distribution (T. Raadik, DNRE, pers. comm.). Furthermore, Cadwallader and Backhouse (1983) suggests that because of redfin's predatory nature, they have the potential to significantly reduce the abundance of smaller native fish species such as pygmy perch, rainbow fish and carp gudgeon in enclosed systems.
Redfin also have the potential to affect native fish through the introduction of pathogens. Redfin can carry the epizootic haematopoietic necrosis virus (EHNV) which is pathogenic for silver perch, mountain galaxias, Macquarie perch, Murray cod and possibly other native fish (Langdon 1989). Lintermans (1991) for example, found that EHNV caused a major decline in Macquarie perch in the Australian Capital Territory, while Hutchison (1991) in Western Australia, found that the distribution of the once common Western A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 75 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles pygmy perch was fragmented, with little overlap with redfin distribution. In addition, predation by redfin may have adverse affects on dwarf galaxias (Galaxiella pulsilla), Yarra pygmy Perch (Edelia obscura), Ewen's pygmy perch (Nannoperca variegata) and juvenile Macquarie perch (Macquaria australasica) (Wager and Jackson 1993). Redfin have also been implicated in the decline of trout cod (Maccullochella macquariensis) because of competition for food and predation (Wager and Jackson 1993).
Methods of Control There have been no attempts to control Redfin in Australian waterways (Clarke et al. 2000). Periodic harvesting of redfin has taken place in dams because of their ability to overpopulate enclosed areas and stunt themselves (Merrick and Schmida 1984). There is little natural spread because of their intolerance of fast flowing waters, but they will thrive when translocated into new areas (Clarke et al. 2000).
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6.1.5: Misgurnus anguillicaudatus (Oriental Weatherloach)
Figure 14: The distribution of Oriental Weatherloach Misgurnus anguillicaudatus in the MDB Source: Lintermans et al. 1990
Overview Oriental weatherloach are native to Asia. The name ‘weatherloach’ derives from the belief, so far unsubstantiated, that the fish becomes restless during changes in air pressure (Allen 1984). The first feral population of weatherloach was reported in early 1984 in the Yarra River (Allen 1984). Prior to these records, only isolated single specimens had been collected (Lintermans et al. 1990). The fish had been imported from Singapore for over 20 years and are a popular aquarium fish kept as a ‘cleaner’ fish (Lintermans et al. 1990; Allen 1984). Oriental weatherloach initially escaped into the MDB when an ornamental dam at Wandiligong on the Ovens River in Victoria, previously stocked with the species sourced from the aquarium trade flooded (Arthington and McKenzie 1997). The spread of this species has also been greatly facilitated by the illegal use as live bait by anglers. Evidence in America regarding the ability of weatherloach to disperse is equivocal, but suggests that their dispersal is facilitated by flood control and irrigation systems. Rapid range expansion of exotic populations in natural drainages are only documented in Australia (Logan et al. 1996). Weatherloach were banned from importation to Australia in 1986 due to their documented feral habits (Burchmore et al. 1990). Oriental weatherloach have since established populations in over 80% of the countries in which it has been introduced including Philippines, North America, Hawaiian Islands and Palauan Islands (Arthington et al. 1999).
Current Distribution and Abundance Oriental weatherloach are established in parts of New South Wales, Victoria, the Australian Capital Territory and Queensland, however, the presence of oriental weatherloach in South Australia and Western Australia remains uncertain (Arthington and McKenzie 1997). Populations of weatherloach exist in the southern and south eastern portions of the MDB: in the Murrumbidgee River (the Australian Capital Territory and New South Wales) and upper Murray and tributaries (New South Wales and Victoria) (T. Raadik, DNRE, pers.comm.). In Victoria oriental weatherloach are abundant in the Yarra and Maribyrnong rivers, Ovens, Broken and Murray rivers as far downstream as Barmah. They occur in both the main channel, anabranches A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 77 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles and off stream wetlands. In the Australian Capital Territory weatherloach occur in Ginninderra Creek and Lake Burley Griffin and in New South Wales they occur in Wingecarribee, Coxs, Murrumbidgee Rivers and Tuppal and Tuggeranong Creeks. Oriental weatherloach also occur in a small suburban creek near Brisbane (Lintermans and Burchmore 1996).
Oriental weatherloach are capable of rapid expansion in range, and the spread of this species throughout the MDB may have been facilitated by water diversion schemes for irrigation supply, river regulation, as well as illegal use of bait fish by anglers. They may benefit from created habitats such as rice fields. Oriental weatherloach are capable of moving overland to disperse and colonise new waterbodies (Lintermans et al. 1990).
Biology and Ecology Oriental weatherloach are often found in cold, still or slow flowing waters with muddy or sandy substrates in which they can burrow and so possibly escape predation. They can survive in modified or degraded habitats and are tolerant of pesticide contamination (Lintermans et al. 1990, Burchmore et al. 1990). Oriental weatherloach are eurythermal, thriving in water temperatures of 2-3°C and have been recorded in some hot springs with temperatures of up to 38°C (Lintermans and Burchmore 1996). They can respire and survive temporarily out of water where they burrow into the sediments and aestivate. Weatherloach respond to an reduced oxygen availability by swallowing air and passing it through a highly vascularised hind gut and expelling carbon dioxide through the vent (Lintermans and Burchmore 1996, Allen 1984). Although this species meets two of the factors proposed by Arthington et al. (1999) for a successful invader, i) previous successful invasions, and ii) large and abundant populations, we know little about the third factor of habitat matching. That is we do not understand what areas of the MDB match the physiological and behavioural tolerance limits, and habitat requirements of the species and therefore cannot accurately predict their ultimate geographical range.
Oriental weatherloach can grow to a length of 10-25 cm and is sexually mature at about 10 cm or 2 years of age (Kochetov and Kochetov 1986). They are able to spawn multiple times, laying 4-8000 eggs per spawning on aquatic vegetation or mud and about 150 000 eggs per season (Lintermans and Burchmore 1996; Allen 1984). The eggs hatch in about 10 days and fry hide amongst the sediment where they feed on small plankton located near the bottom (Kochetov and Kochetov 1986). Adults are omnivorous and feed on aquatic insect larvae, crustaceans, gastropods, rotifers, algae and detritus (Burchmore et al. 1990).
Environmental Impacts There are presently no Australian data on the interactions of oriental weatherloach with native fish species (Arthington and Bludhorn 1995). Lintermans et al. (1990) indicates that there have been no reports of adverse effects of this species in Australia, probably due to the relatively short time they have been known to be feral and the lack of research. Little is known about their potential impact, such as predation, diet overlap, and competition for space, on native aquatic fauna communities, in particular fish communities (Arthington and Bludhorn 1995; Arthington and McKenzie 1997). We also know little about the potential impact to agriculture from high population densities. There is preliminary evidence that the oriental weatherloach is adversely affecting small native fish species such as Galaxias olidus (Arthington and Bludhorn 1995). Due to their high fecundity, hardiness and mobility there is a high risk of self-sustaining populations of weatherloach occurring in a range of habitats (Allen 1984). 78 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Methods of Control Much of the spread of oriental weatherloach has been attributed to aquarium releases and their use as a live bait. Prevention of the spread of oriental weatherloach should be centred on the aquarium trade and anglers. No effective control measures appear to have yet been trialed in Australia.
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6.1.6: Salmo trutta (Brown Trout)
Figure 15: The distribution of Brown Trout Salmo trutta in the MDB Sources: Cadwallader 1996; Clarke et al. 2000; Davies and McDowall 1996
Overview Brown trout are native to Europe. They are found from Iceland to Scandinavia, southward to Spain and North Africa and Eastward to the Black and Caspian Sea (Davies and McDowall 1996). Brown trout have been introduced into numerous other countries and are present on all continents with the exception of Antarctica (Cadwallader 1996). Brown trout were first introduced into the Plenty River, Tasmania during the early 1860s to enhance recreational fishing and were later introduced to Victoria, New South Wales and to a lesser extent South Australia and Queensland waters (Cadwallader 1996, Davies and McDowall 1996).
Along with other salmonid species brown trout have become a popular game fish that provide good angling opportunities. Recreational angling for salmonids forms the basis of a multi-million dollar industry that provides economic opportunities for the general public and commercial industry.
Brown trout have, however, been implicated in the decline and fragmentation of a number of native fish and macroinvertebrate communities (Jackson 1981, Arthington and Bluhdorn 1995, Clarke et al. 2000). They impact on freshwater fish communities through direct predation and competition for food and habitat (Tilzey 1976, Cadwallader 1996).
Current Distribution and Abundance The current known distribution of brown trout is from southern Queensland through the eastern parts of New South Wales, most rivers in Victoria, south-eastern South Australia, south-western Western Australia and Tasmania (Clarke et al. 2000). Water temperatures generally limit their distribution, as they require low water temperatures to breed (Davies and McDowall 1996). However, brown trout can be found throughout some lowland rivers where summer water temperatures are relatively high. Self-sustaining populations of brown trout are restricted to the cooler parts of their distribution, mainly above altitudes of 600 m, while stocking takes place in many lower altitude areas and the warmer waters of New South Wales, Tasmania, South Australia and Western Australia (Arthington and Bluhdorn 1995). 80 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Biology and Ecology Brown trout are a cold water species with optimum temperatures ranging from 4-190C. They may reach lengths of over 1.4 m and weigh over 20 kg, however in Australia they have only been recorded to 1.0 m and 14 kg (Cadwallader 1996). Brown trout are a very active species that typically occur in shallow well- oxygenated waters, where they prefer stream beds of gravel, cobbles and pebbles. They are also often found in areas with large amounts of overhanging riparian vegetation and instream woody debris but they also inhabit deeper holes, lakes and estuaries (Davies and McDowall 1996, Clarke et al. 2000).
Brown trout can reach sexual maturity at the end of their second year if conditions are favourable, however most are sexually active during their third year (Clarke et al. 2000). Spawning takes place during autumn and winter (April-August) over gravel beds, usually located in small tributaries. They will also spawn in lakes and impoundments if suitable substrate and water movement is available (Davies and McDowall 1996). During spawning the female using the underside of her body makes a nest in the gravel, termed redds, and deposits her eggs. The male then fertilises the eggs and the female covers them with gravel to stop them from being swept away in the flow (Roughley 1971). Female brown trout are capable of producing 1200 eggs per kilogram of body weight which take 20 to 72 days to hatch depending on water temperature (Roughley 1971). After hatching, juvenile trout (alevins) remain in the redd until they have absorbed their yolk sac (Cadwallader 1996). After which juveniles maintain a restricted home range until larger trout force them to move on and establish their own territory. During this time they remain highly gregarious and inhabit shallow waters along stream edges and backwaters (Davies and McDowall 1996, Clarke et al. 2000). Newly hatched brown trout are 15-25 mm in length and by the end of their first year are 10 cm in length, however they can double this if suitable conditions prevail (Cadwallader 1996, Clarke et al. 2000). They become increasingly solitary and territorial with increasing size (Cadwallader 1996).
Brown trout feed on a variety of insects from caddis-fly larvae, Coleopterans, Hemipterans, and Dipterans, while larger fish feed on other fish species, terrestrial insects, mice, frogs, worms, crustaceans and molluscs (Cadwallader 1996, Clarke et al. 2000). Food selection varies according to seasons, weather and abundance but brown trout may also consume green algae, leaves seeds and flowers of native plants ingested incidentally with insects (Clarke et al. 2000).
Environmental Impacts Brown trout have had a major impact on the distribution and abundance of some native freshwater fish and invertebrate communities and have been implicated in the decline of some species classified by the IUCN as 'endangered' or 'vulnerable' (Arthington and Bluhdorn 1995, Davies and McDowall 1996, Clarke et al. 2000). The principal impacts of brown trout are direct predation and/or food and habitat competition and introduction of disease (Tilzey 1976, Cadwallader 1996, Clarke et al. 2000).
Brown trout have been responsible for fragmentation of native fish populations and in some cases total replacement of fish fauna (Clarke et al. 2000). For example, brown trout have seriously fragmented or even totally replaced some populations of barred galaxias (Galaxias fuscus) in Victoria (Raadik 1995). Similarly Fletcher (1979) showed that after experimental introduction of brown trout the abundance of mountain galaxias (Galaxias olidus) decreased because of predation and competition. In addition, the diet of brown trout showed positive correlations with the diets of all age-classes of mountain galaxias. Competition for A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 81 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles food resources by brown trout has also implicated in the decline of other galaxiids, Macquarie perch, trout cod and river blackfish (Jackson 1978). Selective predation by brown trout on invertebrates has also resulted in a decrease in the abundance and diversity of naturally abundant species.
The introduction of white-spot disease (Ichthyophthirius multifilis), Ligula, Eustrongylides and Ichthyobodo necator have been linked with the introduction of several salmonid species (Pollard 1974, Cadwallader 1996). The spread of these pathogens through the introduction of exotic fish species has had an impact on some native fish species. For example, large numbers of landlocked common jollytail (Galaxias maculatus) have been infected with Ligula causing a reduction in body weight, inhibition of gonadal maturation and migration to spawning areas (Pollard 1974).
Methods of Control Currently, there are few strategic methods for the control of brown trout. To date, control efforts have been limited to small streams where certain native fish are the focus of recovery plans. These efforts have included removal of brown trout upstream of natural or man-made barriers by electrofishing or piscicides (Lintermans 2000). It appears that even low barriers can effectively exclude brown trout from recolonising upstream allowing the recovery of threatened fish species.
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6.1.7: Oreochromis mossambicus (Mozambique Tilapia)
Overview Mozambique tilapia (Oreochromis mossambicus) occur naturally along the east coast of Africa. Mozambique tilapia have spread throughout tropical areas in the United States, Japan and Europe and also some areas of Australia. The potential for tilapia to spread in northern Australia is significant, due to their rapid growth rate, short maturation time (3-12 months), high fecundity and wide temperature tolerance. However, it is unlikely that tilapia will spread widely in the MDB because of their intolerance of cooler water temperatures.
Current Distribution and Abundance In Queensland tilapia (Oreochromis mossambicus and Tilapia mariae) populations have been found in Brisbane, Townsville and Cairns regions. The former also occur near Carnarvon in Western Australia (McDowall 1996). While natural spread is relatively slow, more rapid spread may be facilitated by human translocation, or via human created routes such as pipelines and irrigation channels. Many populations became established following accidental release from aquariums, fish farms, hatcheries and zoos. In 1998 tilapia were apparently caught from West Creek in the upper reaches of the MDB near Toowoomba (MDBC 2001). However, previous surveys in 1996 had not detected tilapia in West Creek, nor have they been collected in follow-up sampling (David Moffatt, QDNR, pers. comm.). Oreochromis mossambicus breed prolifically in food-rich environments, although they can produce large numbers of small, reproductively mature individuals in over-crowded conditions.
Biology and Ecology Oreochromis mossambicus can grow up to 40 cm long and maturation occurs at 150-160 mm in females and 170-180 mm for males. Fecundity of O. mossambicus is up to 1 200 eggs/year. Mozambique tilapia are mouth brooders, a strategy that results in relatively low juvenile mortality. They build nests, and males are often aggressive when defending these during the breeding season, which occurs between September/October and April/May in Queensland, with up to four broods per year. Fry are released from the mouths of adults in shallow waters once they have reached lengths of 9-10 mm. Time of release also appears to be associated with cues relating to rainfall.
Tilapia are a very hardy species that can tolerate a wide range of water quality conditions including high salinity, both highly acidic and alkaline water, and low levels of dissolved oxygen. Their main vulnerability is low temperatures and the lethal lower temperature (freshwater) is 8-12°C, but increased salinities, which are found through much of the MDB, can help them withstand colder conditions. Die offs of Tilapia have been recorded in the Pine Creek population north of Brisbane at temperatures of 12°C (I. Johnson, Queensland Museum, pers. comm.).
Mozambique tilapia are generally omnivorous. Their preferred food consists of detritus and plant matter and their diet also appears to change with locality. Reports of this species feeding opportunistically on other fish are also common. Anglers in many parts of the world target tilapia because of their firm flesh.
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Environmental Impacts In the Gulf of Mexico, tilapia are likely to compete with native fish such as centrarchids for nesting areas. In addition, where abundant, tilapia’s aggressive breeding habits may alter community structure, while their opportunistic feeding on various food items may cause competition with a broad array of native taxa. Concern has also been expressed that, where common, such as in the estuarine waters of Florida, tilapia may lower local biodiversity through competition for trophic resources and direct predation. In Hawaii, the species is suspected to be a threat to native species such as the striped mullet (Mugil cephalus). They have also been identified as a major factor in the decline of the desert pupfish (Cyprinodon macularius) in the Salton Sea area.
Tilapia also pose a threat to Australian fish and habitats and possible impacts may include competition for food and habitat, declines to macrophyte abundance and degradation to aquatic systems (DPI 2000). However, like carp, there is little sound information about the damage that tilapia cause. There is a strong need for education and further research to define some baseline information about their impacts on native fish populations.
Methods of Control Tilapia are extremely hardy and so it may be very difficult to control established populations with the range of techniques presently available (DPI 1998). For example, tilapia can tolerant very low oxygen levels and it is estimated that approximately double the concentration of rotenone is required to kill Tilapia to that which will kill native fish. Hence, in some situations, care would be needed when using poison to kill Tilapia to ensure that the impact on non-target native species is minimised. Maintenance and restoration of natural habitat may be an effective means for limiting the spread of tilapia and managing them where they have established. However, at this stage the natural lower thermal limits of tilapia (approximately 10oC) may be the most efficient control mechanism for their spread in the MDB.
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6.1.8: Oncorhynchus mykiss (Rainbow Trout)
Figure 16: The distribution of Rainbow Trout Oncorhynchus mykiss in the MDB Sources: Cadwallader 1996; Clarke et al. 2000; Davies and McDowall 1996.
Overview Rainbow trout are native to the western coast of the United States of America, Canada, and Northern Mexico, and have been introduced into all temperate and sub-arctic regions of the world (Sedgwick 1985, Arthington and Bluhdorn 1995, Clarke et al. 2000). Rainbow trout were first introduced into New South Wales from New Zealand in 1894, and eggs from here were distributed to Tasmania in 1898 and Victoria in the early 1900s (Clements 1988, Cadwallader 1996, Clarke et al. 2000). They were then introduced into South Australia and Queensland, and Western Australia in the 1930s (Clarke et al. 2000).
Rainbow trout along with other Salmonid species present in Australia are a popular game fish that provide good angling opportunities. Angling for Salmonids forms the basis of a multi-million dollar industry that provides economic opportunities for the general public and commercial industry (Clarke et al. 2000).
Like brown trout, rainbow trout have been implicated in the decline and fragmentation of native fish (Jones et al. 1990, Shirley 1991). They impact on native freshwater fish communities through direct predation and competition for food and habitat (Tilzey 1976, Cadwallader 1996).
Current Distribution and Abundance Rainbow trout are currently present in waters of New South Wales, Queensland, Victoria, South Australia, Western Australia and Tasmania (Clements 1988, Clarke et al. 2000). Self-sustaining populations generally live in cooler high altitude areas of New South Wales, Victoria, the Australian Capital Territory and Tasmania. Stocked populations are maintained in the warmer areas of Queensland, New South Wales, Victoria, Tasmania and Western Australia (Arthington and Bluhdorn 1995, Clarke et al. 2001). In addition, sea-run trout have been reported in Victorian and Tasmanian streams (Arthington and Bluhdorn 1995).
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Rainbow trout are abundant in rivers and streams down to 300 m in New South Wales and Victoria. They are found in all major tributaries, including: the McIntyre, Gwydir, Namoi, Macquarie, Lachlan, Murrumbidgee and Murray (Clarke et al. 2001). Rainbow trout numbers are highest in the upper Murray, Ovens, Kiewa and Mitta Mitta catchments, where conditions suit, and lowest throughout central and northern New South Wales, northern and western Victoria, South Australia and Western Australia, where conditions are harsher (Clarke et al. 2001).
Biology and Ecology Rainbow trout are a cold water species (4-220C) preferring fast flowing water with high oxygen content (Cadwallader and Backhouse 1983, Kailola et al. 1993). In North America rainbow trout have been known to reach 1.22 m in length and 18 kg in weight, however, in Australia they grow to a maximum of 775 mm and 10 kg in weight (Merrick and Schmida 1984). Like brown trout, rainbow trout prefer streams with large amounts of overhanging riparian vegetation and woody debris for cover, however they also exist in deep holes, lakes and estuaries (Davies and McDowall 1996, Clarke et al. 2000). Rainbow trout become sexually mature in their second and third year, and female trout are capable of producing 1500 eggs per 1 kg of body weight (Merrick and Schmida 1984). They breed during winter and early spring (July-October), and often migrate upstream into smaller streams to do so. Female Rainbow trout seek out gravel beds to spawn in, so water can pass through and oxygenate the eggs (Merrick and Schmida 1984). The eggs are deposited in excavated gravel beds, or redds, by female trout, and subsequently fertilised by the male. The female then disturbs the gravel beds above the redd, in order to cover the eggs with gravel, and so reduce egg drift (Kailola et al. 1993). Rainbow trout eggs are smaller (3-5 mm) than Brown trout's eggs (4-5 mm), however, Rainbow trout eggs develop faster taking 4-7 weeks to hatch (Kailola et al. 1993). The incubation period lasts between 3 and 12 weeks, depending on water temperatures, while newly hatched alevins take 3-10 days to absorb their yolk and enter the water column to fed (Clarke et al. 2000).
Young rainbow trout feed on zooplankton, while adults feed on a variety of organisms including insects, crustaceans, molluscs, fish and any terrestrial organisms that enter the water column (Cadwallader and Backhouse 1983). Rainbow trout, like brown trout, have variable growth rates that depend on a number of factors (temperature, pH, prey availability), however, they have been recorded to grow to 1.4 kg in their first year in Lake Purrumbete (Cadwallader and Backhouse 1983, Clarke et al. 2001).
Environmental Impacts Rainbow trout, like brown trout, have had a significant impact on native fish and invertebrates through direct predation and food and habitat competition (Arthington and Blüdhorn 1995, Clarke et al. 2000). Jones et al. (1990) for example, found that Galaxias olidus had fragmented distribution, and was restricted to marginal habitats with the introduction of brown and rainbow trout. In addition, rainbow trout were found to have migrated further upstream than brown trout, and that there was an inverse relationship between trout biomass and galaxiid biomass.
Methods of Control Currently there are no strategic methods of control for rainbow trout or brown trout. However, control efforts for rainbow trout to date have been limited to specific areas and are the focus of recovery plans for certain native fish species. Control efforts include; building in-stream exclusion structures, designed to prevent access to trout into areas where threatened species occur; biomass reduction, by electrofishing between 86 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles waterfalls; and removal of trout with toxicants to provide a predator-free environment (T Raadik, DNRE, pers. comm.).
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6.1.9: Tinca tinca (Tench)
Figure 17: The distribution of Tench Tinca tinca in the MDB Sources: McDowall 1996; Victorian Fish Database (DNRE).
Overview Tench are native to Europe (Merrick and Schmida 1984) and were one of the first fish species to be introduced into Australia (Clements 1988). They arrived in Tasmania from England in the late 1850s and were liberated into a large reservoir near Cascade (Clements 1988). Tench subsequently arrived in Melbourne from England in the early 1860s (Clements 1988) and during the 1870s were widely distributed throughout Victoria by local acclimatisation societies (Cadwallader and Backhouse 1983). The Royal Society of Tasmania propagated tench in their ornamental ponds (Clements 1988) and by 1882 were firmly established in certain rivers throughout Tasmania (Weatherley 1967). The Royal Society of Tasmania also distributed tench into Victoria, New Zealand and New South Wales (Clements 1988). Tench were first introduced into New South Wales in 1886 (Weatherley 1967).
The impacts of tench on native fauna have not been well documented probably because of their limited distribution. However, Merrick and Schmida (1984) suggest that their feeding habits cause some waters to become muddied.
Current Distribution and Abundance Tench occur within the Murray-Darling system (Brumley 1996) and throughout the coastal rivers of New South Wales, Victoria, South Australia and Tasmania (Arthington and Blüdhorn 1995). The distribution of tench in the Murray River is considered to be patchy and restricted to the middle and upper reaches of its southern tributaries (Merrick and Schmida 1984). Similarly, they have a patchy distribution throughout the south-west and inland New South Wales, and are uncommon except in some lakes (Llewellyn 1983, Arthington and McKenzie 1997). The abundance of tench is highest in the Derwent river basin in Tasmania (Brumley 1996), while in Victoria, tench are found north and south of the divide, with the exception of east
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Gippsland (Cadwallader and Backhouse 1983). In addition, throughout Victoria tench are considered to be sparse over much of their range, however can be locally abundant (Cadwallader and Backhouse 1983).
Biology and Ecology Tench, like carp and goldfish are a member of the cyprinid family. They commonly occur in slow flowing areas with an abundance of macrophyte and deep holes (Merrick and Schmida 1984). They are a hardy species that can tolerate low oxygen levels, temperatures up to 35.20C (Varley 1967), and salinities up to 14 500 ppm (Merrick and Schmida 1984). Spawning occurs between late spring and early summer when water reaches 160C (Cadwallader and Backhouse 1983). In Europe, tench produce 3-4 batches of tiny yellow adhesive eggs at intervals of 14 days in warm temperatures (Brumley 1996). A female tench is capable of producing up to 900 000 eggs and either lays them over aquatic vegetation or on the benthos (Cadwallader and Backhouse 1983). Hatching of the eggs is temperature dependent, however it usually occurs between 3-6 days after spawning. Newly hatched larvae are 4-5 mm long and attach themselves to plants to absorb their yolk sac (Cadwallader and Backhouse 1983, Merrick and Schmida 1984).
Juvenile tench feed on plankton, small insects and crustaceans, while adults are essentially carnivorous, feeding on molluscs, insect larvae, small crustaceans and occasionally plant material (Cadwallader and Backhouse 1983, Brumley 1996). Tench can grow to approximately 700 mm in length and up to 9 kg in weight, however they are commonly 100-300 mm in length (Cadwallader and Backhouse 1983).
Environmental Impacts The ecology of tench and their impacts on indigenous Australian fauna has not been well documented and this is probably a result of their cryptic nature and low scattered abundances. It is however known that the feeding habits of tench causes muddying of dams and ponds (Merrick and Schmida 1984). In Victoria because of its localised distribution they do not appear to have a great effect on local biota (P.S. Lake, pers. comm. in Arthington and McKenzie 1997). Similarly, because of its limited distribution throughout New South Wales, it is believed to have very little impact (P. Gehrke, pers. comm. in Arthington and McKenzie 1997). In addition, the abundance of tench was believed to have declined after the explosion of carp.
Methods of Control In the past there has been no coordinated approach to controlling tench distribution and abundance in Australia. Baseline data such as their distribution and abundance should first be established. Arthington and McKenzie (1997) suggest that a monitoring program is needed to evaluate the distribution and abundance of tench in order to determine if there are significant changes to their range and biomass. Once this has been determined strategic control measures can be implemented. Control measures similar to those for carp should be adopted for tench given that their distribution and life-history strategies overlap.
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6.1.10: Rutilius rutilius (Roach)
Overview Roach are native to Europe, excluding Spain, Italy, Greece and Ireland (Arthingon and Blüdhorn 1995). Roach were first introduced into Australia between the 1860s and 1880s from the United Kingdom as a popular coarse angling species (Arthington and Blüdhorn 1995). It appears that they arrived on a ship with a consignment of forty river and pond fish (Clements 1988). They were originally introduced into Tasmania, and from there into Victoria, New South Wales and Western Australia. The New South Wales Fisheries Board attempted to import roach into Sydney on two occasions as reported by the Australasian in 1907, however they later died (Clements 1988). No records of established populations of roach in Tasmania or Western Australia (Cadwallader and Backhouse 1983).
The impacts of roach on native fauna have not been well documented. However, Clements (1988) and Arthington and McKenzie (1997) have both documented large migrating schools of roach during the spawning season, that potentially have adverse affects on native fauna.
Current Distribution and Abundance Roach are restricted to the south-east coast division of Australia. They have been found in the Yarra, Maribyrnong, Werribee rivers and Lake Eildon, Burrumbeet and Purrumbete (Clements 1988) for some years. In 1975 Lake Burrumbeet apparently teemed with roach up to 2.5 pounds (Clements 1988). More recently roach have been found in the Barwon, Bunyip, Goulburn and Loddon systems (T. Raadik NRE pers. comm.). The distribution of roach in Victoria is considered patchy but locally abundant (Cadwallader and Backhouse1983), while Lake (1959) recorded roach in the Murray river in small numbers. Arthington and Blüdhorn (1995) report that they are uncommon in New South Wales and given their current abundance are likely to little impact. Brumley (1996) also suggested that their range did not appear to be expanding.
Biology and Ecology Roach belong to the family Cyprinidae as do carp, goldfish and tench. Roach prefer to live in lakes, ponds and slow-flowing rivers especially with an abundance of aquatic plants (Brumley 1996). They are active during the daytime, swim in shoals, and react poorly to handling by anglers (Merrick and Schmida 1984). Male roach reach maturity after 2 years, while females take slightly longer, 2-3 years (Cadwallader and Backhouse1983). Spawning takes place over vegetation or a stony bottom during the spring-summer period, when day length increases and the water temperatures reach approximately 150C (Cadwallader and Backhouse1983, Brumley 1996). Females produce between 5000 and 200 000 eggs that are adhesive and approximately 1-1.5 mm in diameter (Merrick and Schmida 1984). Hatching takes 4-10 days depending on water temperature, while larvae are 4.5-6.6 mm in length (Merrick and Schmida 1984). Larvae attach themselves to any hard substrate for a few days to absorb their yolk sac and then form shoals in the shallows.
Growth of roach is slow with females generally growing faster than males. They have been know to live for 12 years (Merrick and Schmida 1984) and reach lengths of 450 mm, however, fish 150-200 mm are more commonly encountered in Australia (Brumley 1996). Juvenile roach feed on planktonic plants and animals, while adults are omnivorous feeding on a variety of organic materials (Varley 1967).
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Environmental Impacts The impact of roach on native freshwater fish has not been well documented, and is probably a result of their limited distribution. However, Clements (1988) did highlight hundreds of thousands of roach migrating into Burrumbeet Creek to spawn during the breeding season. Such abundances suggest that roach may potentially cause problems for native biota. Similarly, high abundances of roach in creeks in the Port Philip Bay region suggest that they may adversely effects native fauna (Arthington and McKenzie 1997).
Methods of Control Existing populations of roach should be targeted for intensive control. Eradicating the species from where it currently occurs will result in a decrease in the expansion of its range and any adverse affects associated. In addition, the general public should be well informed about the potential effects of releasing roach into our natural waterways. Where possible, ongoing monitoring should be implemented to document range expansions and ecological impacts.
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6.1.11: Poecilia reticultata (Guppy)
Overview The guppy is indigenous to northern parts of South America (Brazil, Guyana, Venezuela) and islands of the Caribbean such as Trinidad and Barbados (McDowall 1996). The guppy is a member of the poeciliid family which are a popular aquarium fish and have been established in Australia for many years (Cadwallader and Backhouse 1983). The poeciliid family is sub-tropical with a similar life history to Gambusia holbrooki (Mosquitofish) (Arthington and McKenzie 1997). Establishment of guppies in the wild is not well documented however they were first introduced as ornamental fish and for controlling mosquitoes in the 1960s and 1970s (Arthington 1991, Arthington and McKenzie 1997). Guppies have not spread as widely as Gambusia, however they are established in many coastal creeks near urban centres between Brisbane and Darwin (Arthington and McKenzie 1997, Clarke et al. 2000).
The effects of guppies on native freshwater fish remain unknown, however they are thought to be similar to Gambusia, because of similar diets and life history strategies. Guppies also carry a parasitic nematode, Camallanus cotti, which feeds on the intestines of fish, and has the potential to infest some native species (Hoffman and Schubert 1984).
Current Distribution and Abundance Currently guppies are only found in some coastal creeks and drainage systems of Queensland from Brisbane to Cairns and in the Northern Territory around Nhulunbuy and Darwin (Clarke et al. 2000). It is likely that the distribution of guppies will continue to expand further north because of people moving them from one creek to another, however their movement southwards is likely to be inhibited by temperature tolerances and their dislike of fast flowing waters (Arthington and Blüdhorn 1995, Clarke et al. 2000). Currently guppies are not found within the MDB.
Biology and Ecology Guppies are a tropical to subtropical species that inhabit still or gently flowing waters. They are generally found in loose aggregations along sheltered margins or among vegetation (McDowall 1996). Guppies are a warm water species that do not tolerate temperatures below 150C and prefer temperatures between 23-280C (van Ramshorst 1991).
Guppies are ovoviviparous (egg-live-bearing) with well-developed sexual dimorphism. Male guppies are much smaller and more vivid than their female counterparts and posses a gonopodium, male copulatory organ, that develops from anal fin rays (Clarke et al. 2000). The advantage of this is that fertilisation and development of the eggs take place within the adult where they are not exposed to external risks (Hoedeman 1974). The female can store spermatozoa for extended periods and is capable of producing 2-3 broods for every act of fertilisation (Frank 1969). Gestation takes 4-6 weeks and 4-100 young are produced at birth, which is dependent upon water temperature and quality and quantity of food (Hoedeman 1974, Clarke et al. 2000). As soon as the young leave the brood pouch parental care ceases and the juveniles fend for themselves. Juvenile guppies grow rapidly and are mature after approximately six weeks (van Ramshorst 1991) 92 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Guppies are omnivores that eat plants, algae, terrestrial and aquatic insects, macroinvertebrates and small fish including their own young (Frank 1969, Arthington 1989). Female guppies grow to approximately 60 mm in length, while males only grow to 30 mm (McDowall 1996). Guppies live for approximately 18 months (Clarke et al. 2000).
Environmental Impacts Guppies are regarded as pests in all countries where they have been introduced, even though the environmental impacts have not been fully evaluated (Clarke et al. 2000). The effects of guppies on native fish species are thought to be similar to Gambusia as they share similar diets and life histories. In fact, Arthington et al. (1983) found that in streams around Brisbane guppies suppressed indigenous fish populations, possibly through resource competition.
Guppies in Australia are also known to carry the nematode, Camallanus cotti, which is a significant parasite of many ornamental fish species (Clarke et al. 2000). This parasite feeds on the intestines of fish, and has the potential to infest many native species (Hoffman and Schubert 1984).
As an aquarium species, guppies continue to be placed into waterways by people, however they do not show the same capacity for unassisted range expansion as Gambusia (Arthington et al. 1983). The potential of range expansion especially through human assistance should not however be ignored (Arthington and Blüdhorn 1995).
Methods of Control Existing populations of guppies should be targeted for intensive control. By limiting the abundance of and possibly eradicating the species from where it currently occurs may result in a decrease in the number of translocations. The general public should be well informed about the potential effects of releasing unwanted guppies into natural waterways. Where possible, ongoing monitoring should be common practice to document range expansions and ecological impacts.
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6.1.12: Salmo salar (Atlantic Salmon)
Overview Atlantic salmon occur naturally in the cool waters flowing into the North Atlantic Ocean, from northern Spain through eastern Europe to Iceland, Greenland and along the north-east coast of North America (Cadwallader 1996). Atlantic salmon were first introduced into Australia from the United Kingdom in 1864. Young salmon were introduced into Tasmania, Victoria and New South Wales in order to establish a sea run population similar to those that occur in the United Kingdom (Cadwallader 1996). However, successfully liberated salmon fry migrated from the rivers to the sea as adults and did not return (Kailola et al. 1993). Atlantic salmon were later reintroduced into New South Wales from Canada during the early 1960s and also into Tasmania as part of commercial aquaculture operation (Kailola et al. 1993).
Commercial production of Atlantic salmon forms the basis of a multi-million dollar industry. Approximately 5000 tonnes of fish were produced in 1994 using both freshwater hatcheries and sea-cages, with an estimated value of $80-100 million (Davies and McDowall 1996). Commercial culture of Atlantic salmon only occurs in Tasmania where the fish are raised in bays along the southern and eastern coasts, and at Macquarie Harbour on the west coast (Kailola et al. 1993).
The impact of Atlantic salmon on native fauna remains unknown. However, they may have similar affects on native fish fauna as brown and rainbow trout because of similar in feeding habits.
Current Distribution and Abundance Currently there are no records of self-sustaining sea-run populations of Atlantic salmon in Australia (Davies and McDowall 1996). Numbers are maintained by annual stockings into Lake Jindabyne, Oberon Dam, Wentworth Falls Lake and Burrinjuck Dam (Llewellyn 1983, Merrick and Schmida 1984). Atlantic salmon are also cultured in large numbers in Tasmania and stocked into New South Wales (Arthington and McKenzie 1997), as well as being reared in private and government freshwater hatcheries in Victoria (Davies and McDowall 1996).
Populations of salmon have been found in the headwaters of the Murray River and streams of the south coast of New South Wales (Arthington and Blüdhorn 1995), in the Rubicon and Latrobe rivers, Victoria, where they are believed to be escapees (Davies and McDowall 1996), and in the lower Murray River in South Australia where they are presumed to be escapees from commercial fisheries in Victoria and New South Wales (Cadwallader 1996). Atlantic salmon are commonly found along the southern and western coast of Tasmania, and these are also believed to be escapees from sea cages (Davies and McDowall 1996).
Biology and Ecology Atlantic salmon like Rainbow and Brown trout prefer cool to cold waters and migrate upstream to spawn (Kailola et al. 1993). In their native range, Europe and North America, Atlantic salmon inhabit seawater for most of their lives only returning to freshwater to spawn (Kailola et al. 1993). Currently there is no published information on the life history of Atlantic salmon in Australia (Kailola et al. 1993), however, when spawning occurs it is believed to resemble that of Brown trout (Davies and McDowall 1996). Overseas information
94 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles suggests that young salmon live in freshwater for up to three years, after which time they migrate to the sea (smolts) to feed (Migdalski and Fichter 1977).
Atlantic salmon can grow to 150 cm in length and 38 kg in weight, however fish found in Australian waters rarely exceed 3 kg (Kailola et al. 1993). Like brown and rainbow trout, Atlantic salmon growth rates vary with water temperature and food availability. Optimal temperature range is between 70C and 170C, however in Australia Atlantic salmon may grow more rapidly than salmon in their native range because of Australia's extended growing season (Kailola et al. 1993).
Studies conducted overseas on the feeding behaviour of juvenile salmon indicate that they consume large quantities of food during summer and are usually taken by drift feeding (Merrick and Schmida 1984). Atlantic salmon feed on insects, other fish, and amphipods (McAllister and Crossman 1973). Australian stocks of Atlantic salmon are believed to have very low genetic diversity because only limited numbers were introduced in the early 1960s (Arthington and Blüdhorn 1995, Kailola et al. 1993).
Environmental Impacts The impact of Atlantic salmon on Australian native fauna remains unknown. As a result, information is often anecdotal and/or based on the impacts of similar species such as brown and rainbow trout. It is likely that their impacts would overlap with brown and rainbow trout given their similarities in feeding and spawning behaviour.
Methods of Control Currently there are no methods for controlling Atlantic salmon in Australia. An approach similar to brown trout should be adopted. Existing populations of salmon should be targeted for biomass reduction by electrofishing between waterfalls, building barriers and removal of salmon with toxicants to provide a predator-free environment. Limiting the abundance of and possibly eradicating the species from where it currently occurs has the potential to reduce their impacts on native fauna. Where possible, ongoing monitoring should be common practice to document range expansions and ecological impacts. Importantly, ongoing stocking of this species into public waterways should be reviewed.
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6.1.13: Salvelinus fontinalis (Brook Trout)
Overview Brook trout are native to the eastern coastal drainages of North America from northern Canada, south into the United States (Merrick and Schmida 1984, Davies and McDowall 1996). Brook trout were first introduced into Australia from North America in the early 1880s, however they did not become established (Cadwallader 1996). Further introductions were made into Tasmania in the early 1900s and into streams on the mountain tablelands of New South Wales in the 1970s (Davies and McDowall 1996). Brook trout now occupy a limited range in New South Wales and Tasmania. In both states there are some self-sustaining populations and those that require continuous stockings.
Along with other salmonid species, brook trout are a game fish. Recreational angling for salmonids forms the basis of a multi-million dollar industry that provides economic opportunities for the general public and commercial industry. Approximately one million brook trout have been released into public impoundments in New South Wales since 1976 (Merrick and Schmida 1984).
The impacts of brook trout on Australian native fauna are unknown. However, it would be reasonable to assume that their impacts overlap with other salmonid species such as brown and rainbow trout and Atlantic salmon, given their similarities in feeding and spawning behaviour.
Current Distribution and Abundance Brook trout are found in New South Wales, Tasmania and South Australia (Arthington and Blüdhorn 1995). Self-sustaining populations of brook trout exist in Clarence Lagoon and the lakes of the Tyndall ranges in Tasmania, and in one stream in New England, New South Wales (Davies and McDowall 1996). Regular stocking of brook trout still take place in Tasmania, New South Wales (Lake Jindabyne) and South Australia (Kailola et al. 1993). Brook trout have also been recorded in mountain streams of New South Wales (Llewellyn 1983) and Tasmania (Allen 1989). However, brook trout are regarded as uncommon and are not well suited to Australian conditions (Arthington and Blüdhorn 1995).
Biology and Ecology Like rainbow and brown trout, brook trout are a cold water species that commonly spawn in feeder springs of streams and lakes (Migdalski and Fichter 1977). Brook trout inhabiting streams commonly move into their headwaters where they mature at a smaller size (Davies and McDowall 1996). Brook trout do not compete well with rainbow and brown trout, which probably explains their limited distribution (Davies and McDowall 1996). The reproductive biology of brook trout resembles that of the brown trout, with spawning occurring in late autumn, April-June (Fulton 1990). Females lay their eggs, approximately 4 mm in diameter (Llewellyn 1983) in gravel nests (Fulton 1990, Llewellyn 1983) or on beaches (McAllister and Crossman 1973). Hatching of eggs takes at least 28 days possibly longer with colder temperatures (Fulton 1990).
In Australia, brook trout have been known to reach 850 mm in length and 6.5 kg in weight (Cadwallader 1996), however they generally grow to approximately 1.5 kg (Llewellyn 1983). Brook trout feed on a variety of different food types ranging from other small fish to macroinvertebrates and insects, crayfish and molluscs (Migdalski and Fichter 1977). 96 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles
Environmental Impacts The impacts of brook trout on Australian native fauna are unknown. Very few studies have been conducted on the impacts of brook trout, because of their limited distribution. As a result information is often anecdotal and/or based on the impacts of similar species such as brown and rainbow trout and Atlantic salmon. Having said this, it would be reasonable to assume that their impacts do overlap with brown and rainbow trout and Atlantic salmon, given their similarities in feeding and spawning behaviours.
Methods of Control Currently, there are no strategic methods for the control of brook trout in Australia. An approach similar to that for brown trout should be adopted. Existing populations of trout should be targeted for biomass reduction by electrofishing between waterfalls, building barriers and removal of trout with toxicants to provide a predator-free environment. Limiting the abundance of and possibly eradicating the species from where it currently occurs has the potential reduce their impacts on native fauna. Where possible, ongoing monitoring should be common practice to document range expansions and ecological impacts. However, more importantly the value of continued stocking of non-native species into Australian rivers should be reassessed.
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6.2 INVERTEBRATES
6.2.1 Cherax tenuimanus (Marron)
Overview The marron (Cherax tenuimanus) is endemic to Western Australia with its natural distribution being from south of Perth to Albany particularly in the Jarrah forests (Merrick and Lambert 1991). Marron have been translocated by both commercial or recreational industries, primarily to stock farm dams, ponds, or other waterways to provide a food source or alternative income (Horwitz 1990).
Current Distribution and Abundance The range of marron has been extended in W.A. and they are also found in South Australia, southern Queensland and throughout NSW in farm dams and aquaculture ponds (Horwitz 1990). The species was first introduced into Queensland and Northern NSW in 1979 (Austin 1985). They have also been found in creeks in national parks of Kangaroo Island off the South Australian coast and these are presumably escapees or from illegal introductions from local aquaculture facilities (Horwitz 1990). Marron have also been identified from water supply dams on the Mornington Peninsula in southern Victoria.
The distribution of marron within the Murray-Darling system is somewhat unclear, however they are known from northern Victoria on the NSW/Victorian border in an aquaculture trial. The species is also cultured in south-western NSW in small scale aquaculture farms (I. Growns, NSW Fisheries, pers. comm.). Permits for marron aquaculture in some areas of the MDB in Queensland do exist, however colonisation of natural waterways outside of these facilities may be restricted when water temperatures exceed 26°C (Steve Brooks, Queensland Fisheries Service, pers. comm.). Victoria is the only state where marron are declared a noxious species, so possession of marron is illegal without written permission from the Minister.
Biology and Ecology Marron are naturally found within rivers, with substrates ranging from clays and silts to gravel (Horwitz 1990), although they do flourish in still waters. They are only found in permanent waters as they do not have the ability to survive drought by burrowing. Marron do, however, build short unbranched burrows under rocks, ledges or logs. Marron tend to inhabit the lower reaches of rivers and are rarely observed in feeder streams (Shipway 1951).
Marron are opportunistic night feeders (omnivorous) and their main food consists of plant material and small animals. They require high oxygen levels (6.5 ppm) and shows signs of distress at 2.0 ppm and die at 0.9 ppm (Shipway 1951). They can tolerate temperatures from 8-26 °C, pH of 6.3-7.6 (Horwitz 1990) and salinities up to 17 000 ppm (Merrick and Lambert 1991).
Mating occurs once a year in spring between September and October and is stimulated by increasing water temperature (Shipway 1951). Some females reach maturity in their second year but most mature in the third. Females carry between 100 and 900 eggs, depending on body size, which are held under swimmerets where they are incubated for 3-4 months. After hatching there is a one-month larval period where larvae stay 98 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles attached to the female, during which period they undergo several moults before being released as small adults (approx. 6 mm long). In the first year of growth marron reach about 45 g and 120 g after the second year (Shipway 1951). Marron can grow to a total length of 385 mm and 2.5-2.7 kg in weight (Merrick and Lambert 1991).
Environmental Threats Potential problems associated with the translocation of marron include the introduction of disease, competitive interactions between native and introduced species and habitat alterations.
A number of commensal and parasitic organisms occur in crayfish populations in Australia. One of the most significant is the microsporidian Thelohania which has been known to cause mortality in crayfish. However, there are no accounts of marron being infected with Thelohania in Australia (Villarreal and Hutchings 1986).
Of the many other commensal and parasitic organisms occurring on crayfish in Australia, their incidence is apparently low and they only become a problem under intensive culture conditions (Merrick and Lambert 1991). In a study conducted by the South Australian Department of Agriculture (O'Donoghue et al. 1990), crayfish from all over the state were tested for commensal and parasitic organisms. Of the 17 genera of organisms found only three, the microsporidian parasites Thelohania and Pleistophora and the trematode parasite Microphallus were found to be cause for concern. Of these, only Thelohania has been associated with crayfish mortality, the others merely making the appearance of saleable meat unsuitable for marketing within the aquaculture industry.
The other major concern following introduction of marron is possible displacement of indigenous species due to competition. Marron are omnivorous, as are other indigenous crayfish, and may compete for food as well as space. Particularly with other non burrowing crayfish as these may share similar habitats. It should be noted that marron is the largest of the Cherax species and this may give it an added competitive edge. In Devil Bend Reservoir in southern Victoria where marron are present in large numbers there are no common yabbies (C. destructor). However, according to the local weir-keepers they were present before the marron colonised the reservoir, perhaps indicating that they have out-competed the yabby in that situation.
Introductions of exotic freshwater crayfish into natural environments is also undesirable as they may alter conditions by increasing turbidity or by destroying aquatic vegetation (Austin 1985).
Methods of Control The potential spread of marron could be controlled by preventing the importation of non-indigenous freshwater crayfish, by preventing the release of aquarium and farm held crayfish into waterways, by ensuring translocated stock are declared to authorities and by ensuring the disease free status of translocated animals (Horwitz 1990).
The only known effective method of eradication is poisoning, however this is not species-specific and is only effective in small enclosed systems. In large impoundments or riverine ecosystems cost and lack of specificity make this form of eradication impractical.
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6.2.2 Pseudosuccinea columella (American ribbed fluke snail)
Overview This snail is native to eastern North America, but is now found in Australian, Central America, Cuba, west North America, South Africa, Europe and New Zealand. It was first recorded in Australia from Sydney in 1973 (Boray 1978) and is now well established and rapidly spreading throughout temperate Australia (Ponder and Waterhouse 1997). It is an effective intermediate host for sheep liver fluke (Fasciola hepatica), a parasite endemic to many areas in the MDB, and it may be more effective at dispersing sheep liver fluke than native snails (e.g. Austropeplea tomentosa) that carry the fluke.
P. columella has been associated with an outbreak of sheep liver fluke in Western Australia in 1987, as it was the only snail present in Western Australia known to carry the fluke. It took 3 years to eradicate the fluke again from WA.
Introduction pathway Lymnaeids are widely used as aquarium snails, which is how P. columella may have first entered Australia in NSW and, more recently, Victoria. While initially this snail had a metropolitan distribution, it is now spreading into grazing areas (Boray et al. 1985).
Biology and Ecology P. columella is a self-fertilising, egg-laying, omnivorous snail that seems to prefer slow or non-flowing water and can thrive in eutrophic conditions. In its native North America it can have an amphibious habit and thus survive periods of desiccation.
It is an intermediate carrier of sheep liver fluke (Fasciola hepatica) (Boray 1978). . This fluke is also carried by native Lymnaeids, but the distribution and ecological requirements of the native species may be more restricted than that of the introduced species. For example, the native A. tomentosa is generally found in pools on farms, while the introduced P. columella can also be common in creeks. As a consequence of this difference in distribution and ecological requirements the invader could potentially contribute to the survival of the parasite through periods of drought by maintaining parasite population in areas that are less likely to dry out.
In New Zealand liver fluke infections have been reported to increase following the establishment of P. columella. Whilst native New Zealand snails also carry the fluke the different ecological requirements of the alien species compared to the native snail host of the fluke can complicate liver fluke control programs (Pullan et al. 1972). It is highly likely that similar differences in ecological requirement exist between native snail hosts and the introduced snail host in Australia, but this remains speculative at this stage in the absence of adequate ecological knowledge about these snails.
Methods of Control Control of P. columella in Australia has only been dealt with in terms of controlling sheep liver fluke, F. hepatica with no distinction being made between native and non-native snails (Boray 1999).
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Research priorities Information on the distribution, population biology and ecology of P. columella and its interaction with native Lymnaeids, in particular the native snail carriers of fluke, is required for the MDB. Different ecological requirements between native and exotic lymnaeids may have implications for the relationship between irrigation and distribution of sheep liver fluke in the Basin. As the presence of the alien lymnaeid may have repercussions on the control of sheep liver fluke, as it has been suggested is the case in New Zealand, it may also be important to identify areas that these snails may still spread to.
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6.2.3 Potamopyrgus antipodarum (New Zealand mudsnail)
Overview Potamopyrgus antipodarum is native to New Zealand, but is now found in Australia, Europe and North America. It was introduced to Australia probably around 1800, probably in ballast (Ponder 1988). In Australia it is as yet restricted to eastern Australia and is well established in Tasmania, South Australia, Victoria and New South Wales. A recent record from Western Australia was probably a misidentification.
P. antipodarum can occur in extremely high densities of over 100 000 individuals per square metre. There have been reports of this snail blocking water pipes and water meters and it is likely that the snail has been distributed through water pipes (Ponder 1988).
Similar to other snails P. antipodarum is an intermediate host to trematode parasites. So far Australia appears to be the only place it has invaded where it is also found to carry parasites (Schreiber et al. 1998) In its native New Zealand it has been reported to carry up to 13 different species of trematodes, the ultimate host of which are thought to be waterbirds (Winterbourn 1973). It is not known whether water birds in Australia also carry the trematode parasites that occur in P. antipodarum, nor do the effects of these parasites on birds appear to be known
There is some data suggesting that this snail was widespread in the lower Murray in 1980-1985, but not in 1987-1989 (Boon et al. 1992). However, as P. antipodarum can be mistaken for several species of native hydrobiids misidentifications are common and its distribution in the MDB is uncertain.
Introduction pathway The introduction of P. antipodarum to Australia is thought to have occurred directly from New Zealand with dry ballast and/or vessels of drinking water in boats. Its introduction to North America is thought to have been associated with the importation of fish eggs from New Zealand to the USA for aquaculture purposes (Zaranko et al. 1997).
P. antipodarum can disperse rapidly and efficiently, possibly by floating both by itself and on algae, transport by birds (Ribi 1986) and fish, and by crawling in one direction against the current along the bottom of a stream (Haynes et al. 1985).
Biology and Ecology P. antipodarum give birth to live young and thus do not have an egg stage exposed to environmental controls. Invading populations are dominated by female snails, indicating that P. antipodarum reproduces by cloning in the countries that is has invaded. In its native New Zealand, on the other hand, this species reproduces both sexual and asexually (Winterbourn 1970).
This species has very broad habitat requirements and environmental tolerances and is able to thrive under saline conditions. P. antipodarum can be very abundant in highly disturbed and eutrophic lakes and streams and can rapidly recolonise following flow disturbances. It also can feed on an extremely broad range of foods, from filamentous algae through to decaying remains of other invertebrates. Fish, leeches and 102 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles waterfowl are its common predators elsewhere, but whether this is also the case in Australia has not yet been established.
Environmental Impacts The impacts of P. antipodarum have only been investigated to a very limited extent and on a small range of other invertebrates (Schreiber et al. in press). There is no work on the effects of this snail on native species of the same family, a specious group of endemic Australian snails of high conservation value (Ponder 1994).
Research priorities Given the conservation importance of native hydrobiids, the effects of this invader on native hydrobiids remains a research priority. Similar to other alien invertebrate species though the distribution of this snail throughout the MDB is unknown. Distributional knowledge together with knowledge on dispersal pathways is required for risk assessment on the impacts of this invader in Australian ecosystems.
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6.2.4 Dreissena polymorpha (Zebra mussel)
Overview This medium-sized bivalve, which has not yet been found in Australia, is listed as one of the ‘100 of the world’s worst invasive alien species’ by the World Conservation Union (IUCN) (Invasive Species Specialist Group 2001). In the Great Lakes area of North America alone the cost of damages of this mollusc to water intake pipes and water filtration and electricity generating plants has been estimated around $100 000 000 (Pimentel 2000). However, conditions in many parts of the MDB are suitable for this invader and the risks of D. polymorpha or other similar bivalves invading Australia need to be assessed.
Introduction pathway Zebra mussels occur naturally in lakes and the lower reaches of rivers in eastern Europe, from where they invaded western Europe and North America. They are thought to have been distributed predominantly through ballast water and hull fouling. Other vectors of dispersal, however, include water diversion channels between catchments, distribution with products in the aquarium trade, by-product of fish stocking, any infrastructure materials transported between water bodies, on floating vegetation and other debris, downstream transport of planktonic larvae in water currents, overland transport on boat hulls, trailers, aquatic vegetation attached to boat trailers (Griffiths et al. 1991; Napela & Schloesser 1993).
Biology and Ecology D. polymorpha have separate sexes and their life cycle includes a planktonic, veliger larval stage, which is relatively rare among freshwater bivalves and aids the extremely effective dispersal ability of this mussel. Females can release in excess of one million eggs per spawning event. In areas with cold winters spawning starts when water temperatures become suitable, however, in warmer areas, such as in the southern part of its native range in eastern Europe, planktonic larvae are present all year-round.
Population explosions are common, with maximum densities of up to 700,000 per m2 reported in an intake canal of a hydroelectrical plant in the USA – an aspect central to the high economic costs associated with this alien species.
D. polymorpha has a byssal apparatus that allows it to attach to any solid surface and thus, in the North American Great Lakes, it could colonise areas where native mussels were absent. Whilst the zebra mussel generally prefers solid surfaces, it will spread to soft surfaces by forming colonies on the shells of con- specifics and other species, including other invertebrates such as crayfish.
Zebra mussels have broad environmental tolerances and can occur in estuaries and brackish waters. They are voracious filter feeders and their high filtration rates can result in a reduction of food resources for zooplankton and a dramatic reduction in turbidity (Ricciardi et al. 1996; Strayer et al. 1999).
Environmental Impacts Impacts on their physical environment are mostly associated with high densities resulting in fouling of any suitable surface, including boat hulls, jetties, water pipes, or any other equipment associated with or left in
104 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles water bodies. Zebra mussels were thought responsible for water supply outages in 1989-1990 to areas dependent on water from the western Lake Erie in North America.
Impacts on other biota are also related to high densities and zebra mussels are thought responsible for the extinction of several native, North American mussel species. Zebra mussels can have direct impacts on other biota by swamping any surface available for colonisation. They can have direct impacts on other mussels by attaching to their shells, including the gape, which prevents mussels from closing their shell. Zebra mussels are known to colonise the exoskeleton of other invertebrates such as crayfish and very high densities of young larvae settle on macrophytes. This species can alter natural food webs and potentially decouple nutrient-chlorophyll relationships. Zebra mussels have been found to increase benthic organic matter through faeces and pseudofaeces production and this has been related to increases in benthic invertebrate densities at the detriment of open water fauna. Even control methods for zebra mussels are problematic as they can result in a large biomass of rotting mussels causing further environmental problems.
Methods of Control Currently physical and chemical methods are used to combat the invasion of this invader in North America. For example, mussels are removed from surfaces with hydroabrasion and mechanical scraping and are sieved from flowing water using micro-sieves. Drying and heat treatments are also used, and some success was achieved by manipulating water velocities. Chemical methods, such as chlorination, surface coating and the use of special materials have also been applied.
There is, however, no doubt that the most effective way of control is to interrupt transport opportunities and prevent this invader from arriving in a country in the first place.
Research priorities Risk assessments that identify the activities that put us in danger of invasion by bivalves, such as Dreissena polymorpha, are a priority to prevent the introduction of these alien species. Areas and habitats in the MDB that are most at risk from this invader need to be identified and invasion risks need to be minimised. This can be achieved by identifying potential transport pathways and dispersal mechanisms for adults and larvae, such as quantifying risks associated with: • irrigation and aquaculture • aquarium trade • fishing and fish stocking • leisure boating • commercial boating • cross-catchment connections and activities • quarantine issues • water industry infra-structure.
Risk management strategies, combined with educational strategies developing the ability to detect alien bivalve species in Australia, need to be developed to allow early detection and appropriate and effective responses to the arrival of alien species.
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6.3 PLANTS
6.3.1 Lippia Phyla canescens (Kunth) E.Greene
Overview Lippia Phyla canescens is one of two species in the genus Phyla, family Verbenaceae, in Australia. The exact date and reason for its introduction have not been established, but herbarium specimens suggest it is a relatively recent arrival, reaching Australia in the 20th century.
Lippia is now well-established as a dominant and dominating species on floodplains, particularly in northern parts of the Murray-Darling Basin, where it is recognised as a environmental threat to floodplain biodiversity and as an economic threat to floodplain grazing enterprises. Lippia is now one of the most serious floodplain weeds in inland eastern Australia, and a survey showed it was rated a significant pest in eight of thirteen bioregions in the Murray-Darling Basin.
Information on lippia ecology and impact is sparse. There is no current research and reviews can only re- cycle information from one published report and one taxonomic revision, fleshed out by comments taken from reports, species lists and observations of colleagues and field workers.
Despite its wide distribution, lippia Phyla canescens is not a significant weed in international terms, being recognised as a weed only on Australian floodplains and in parts of France.
Current Distribution and Abundance Lippia Phyla canescens occurs in riverine habitats in warm temperate areas within the Murray-Darling Basin, such as floodplain wetlands, riverbanks and littoral zone of billabongs. Generally it occurs on soils known as vertisols (grey clays with 30% clay to black earths with 75% clay). Although currently limited to freshwater habitats in the Murray-Darling Basin, lippia is known to be tolerant of brackish conditions.
Its distribution, as indicated by herbarium specimens shows two foci: one on the lowland River Murray, another in inland floodplains of Queensland. Incorporating field knowledge as well allows a more practical type of distribution to be mapped, showing lippia infestation using a 3-tier ranking. Thus lippia infestation is ‘sporadic’ or ‘limited’ along lowland rivers in the southern parts of the Basin (Lachlan, Murrumbidgee, Murray, Edwards) but is ‘severe’ mainly on northern floodplains such as Gwydir and Macquarie, as well as parts of the Lachlan River further south.
Lippia is not restricted to the Murray-Darling Basin, but has also been recorded near Sydney, near Kalgoorlie in WA, in the Mount Lofty Ranges of SA, and in highlands of south-eastern Queensland. Outside Australia, lippia has been introduced into parts of North America, parts of Africa, southern India. In coastal wetlands of southern France, lippia is expanding into brackish plant communities and is posing a threat to wetland biodiversity.
Lippia Phyla canescens is closely related to P. nodiflora, but can be distinguished from it by leaf and inflorescence characteristics. Distribution maps of herbarium specimens shows the species are allopatric, 106 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles with P. nodiflora occurring mainly in tropical and sub-tropical Australia, as well as coastal areas. This may change, as P. nodiflora is widely sold in south-eastern Australia as a hardy ground-cover. Lippia P. canescens has been recognised as a species separate from lippia P. nodiflora only recently (Munir 1993).
Earliest herbarium records of P. canescens date back to 1929 from South Australia. It was first recognised as a weed in the 1950s in the Condamine catchment, Queensland.
Biology/Ecology Lippia is a prostrate, low-growing perennial herb, with a robust woody taproot. Its leaves are bluish-grey. The globular inflorescence with white-pinkish bee-attractive flowers is held erect, 1-5 cm high. Flowering may occur at any time through spring-autumn, unless the plant is droughted.
For lippia, reproduction may be by seed, by lateral extension or by regrowth from fragments. Seed ecology is little known. With lateral expansion, individual plant put out stolons over a metre long. As these can root at the nodes, this forms a dense mat that prevents other species from establishing and that smothers existing plants. It is these characteristics that mean that lippia is actively promoted as a turf or ground cover. Re- growth from fragments typically occurs after flooding.
Bare areas around lippia mats have been attributed to localised release into the subsoil of chemicals inhibitory to the growth and establishment of other species, although it remains to be demonstrated whether these are due to allelopathy or to resource capture. Release of inhibitory chemicals is a characteristic of several species in the family Verbenaceae.
After dry periods, lippia responds rapidly to moisture and is capable of a rapid growth response and extensive flowering with improved conditions, either through rainfall or flooding.
Lippia has several attributes consistent with its weedy character, such as vegetative and sexual growth, environmentally hardiness, and has a few mechanisms of competitive exclusion.
The plant has a thick woody central taproot, up to 80 cm long, as well as a fibrous root system. This dual root system is probably an effective strategy for a plant growing on infrequently-inundated floodplains. The deep tap root is believed to give lippia competitive advantage under dry conditions, allowing it to access soil moisture from deeper within the soil profile and beyond the root zone of other species. The fibrous root system is suitable for opportunistic capture of transient moist conditions (ie rainfall events or brief floods), a characteristic shared with associated grasses and sedges.
Although it is probably not adapted to photosynthesise under water, lippia is tolerant of being temporarily inundated, and is stimulated to grow (probably through cell extension) to the water surface. Such growth is brittle, and breaks readily, for example in response to waves. The resulting fragments float, at least for a while, and as they are viable they can re-establish if stranded on wet muds.
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Environmental Threats Its wide environmental tolerances, of dry and flooded conditions, of freshwater and brackish habitats, its range of re-growth/establishment strategies and its effectiveness at resource capture and competitive exclusion make lippia a formidable weed, in both economic and environmental sense.
The principal threat posed by lippia is to floodplain biodiversity. Lippia is believed to be invading inland floodplains and replacing perennial floodplain species such as Eleocharis acuta and Paspalum distichum. Not only is this a localised loss of native and palatable species, it is also a major structural change in floodplain vegetation, from sedgelands or grasslands to a herbland, with unknown consequences for dependent fauna.
In addition, there is a suite of secondary environmental effects related to soil de-stabilisation that are attributed to lippia. The deep tap root effectively dries out the surface soil, making it prone to collapse or to erosion, and bank slumping occurs with effects that are disproportionate to the absolute magnitude of the erosion: flood runners on floodplains become wider, and cut down thus alienating the floodplain and changing flood discharge-inundation relationships significantly and permanently; the eroded material may be locally deposited or flushed through to downstream river, leading to silt-clay deposits and turbid water; loss of local seed bank with eroded material means the degraded environment is now more suitable for opportunistic species, not necessarily the original native species.
Methods of Control Control can be achieved using herbicides, and in pastoral country active management such as cultivation is usually also needed to encourage a perennial native grassland as replacement. Timing is critical. However using herbicides over extensive properties is not satisfactory, due to costs incurred, the variable effectiveness and the fact that herbicides offer only temporary control rather than eradication. Successful strategies are being developed by individuals but do not have wide currency. The use of herbicides is not consistent with conservation goals and principles of sustainability and alternative integrated strategies need to be developed for floodplains.
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6.3.2 Willows (Salix spp.)
Overview Willows are trees or shrubs Salix spp. in the family Salicaceae. World-wide, there are over 300 species, mostly from the northern temperate regions, although a few species occur naturally in the sub-arctic and a few in warm temperate regions. For practical purposes, it is useful to recognise three groups: trees; shrubs and osiers; and dwarf arctic and alpine willows. At least about fifteen willows, species and hybrids, are known to be naturalised in Australia. The most common and widespread are Weeping willow Salix babylonica, Crack willow Salix fragilis, and Golden weeping willow Salix x chrysocoma; Black willow Salix nigra is often described as aggressive. In addition to the naturalised species there are several cultivars in cultivation for horticulture, and new clones continue to be introduced.
No Salix spp. are native to Australia, all are introduced. Willows are an invasive species in several parts of the southern hemisphere, notably New Zealand and have become invasive, even within their natural range on rivers in North America.
Willows have been planted in Australia for over 150 years. They were first introduced mainly for ornamental purposes, due to their attractive form and bark colourations, and for stabilising banks or roadsides, such as Common Osier S. viminalis and S. purpurea in the Snowy Mountains; several thousand willows have been planted in some catchments. Some species have been introduced for their timber, such as Cricket bat willow S. alba var caerulea. Because of their centuries-long deliberate cultivation in Europe, and because of their relatively long history in Australia, willows are considered by some to be part of a local European heritage.
The family Salicaceae is known for its tolerance of water-logged conditions, rapid growth, distinctive and useful timbers, and capacity for hybridisation. The Salicaceae also includes the genus Populus, poplars and cotton woods, which shares many of these characteristics with willows.
Current Distribution and Abundance Accurate and precise knowledge of the distribution of individual Salix species across the Basin is not readily available due to incomplete and inadequate records, and to very real difficulties in correctly identifying the different species and hybrids. Distribution patterns have undergone substantial changes over the last decade, particularly in cooler upland areas, as seeding willows have established and become new foci for dispersal. Currently, about a dozen species are expanding across Australia. As yet, willows occupy only a fraction of their potential range.
It is only within the last decade that the main and ecologically most significant hybrids have been recorded and that useful field guides to species and hybrids have been produced.
Biology and Ecology Willows occur at the land-water interface of wetlands or rivers with a permanent or reliable water supply during the warmer months, such as upland creeks, weir pools, parts of regulated rivers, farm dams, and irrigation channels. The presence of willows, notably Weeping Willows such as S. babylonica, in semi-arid A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 109 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles and hence otherwise hot dry regions of lowland rivers, is an indicator or altered water regime. In North America, they are generally pioneer species, responding to disturbances, where they regenerate on bare sediments or point bars, and are eventually replaced by slower-growing, longer-lived riparian trees.
Unlike native riparian tree species, willows are deciduous, shedding all their leaves in autumn over a relatively short period. The canopy re-grows in spring, the exact time being dependent on species and climate.
Willows spread by vegetative means as well as by seedling establishment. Vegetative reproduction occurs when viable fragments such as branches and twigs break off or are broken off, and are carried downstream and eventually lodge or are deposited. This type of spread tends to be uni-directional. In contrast, seeds are small and well-adapted for wind-dispersal, thus spreading by seeds may be in any direction, over several hundred metres or more, depending on turbulence. Seeds are small, lack an endosperm and are wind- dispersed.
Willows are usually considered to be dioecious, meaning that male and female flowers occur on separate trees. Until recently, it was thought that all Australian material conformed to this, and hence that no seeds were formed. It is now known that several species at least can be bi-sexual, and that the formation of seeds is quite common, being produced from male and female material of the same species, or between species and hybrids. Seeding willows are now seen as a major environmental threat in some areas.
Reproduction ecology of willows has some interesting features. Seeds are small and have no endosperm. For each species, dispersal appears to be temporally-constrained to 3-4 week period in spring, and occurs about a month after flowering. Seeds landing on wed muds or newly exposed sediments, ie in open moist areas with no competition, germinate rapidly, usually in 1-2 days. Germination is not constrained by temperature but seedling establishment has quite specific water regime requirements and tolerances. Young seedlings are sensitive to water stress, such as caused by falling water levels, and to being scoured by higher flows: in addition, seedlings can tolerate being submerged for about 4 weeks but appear not to grow during this time. Seed viability is apparently low: limited trials with Australian species suggest no viability beyond 3 weeks, whereas overseas work shows that for one species, Black willow S. nigra, may last for up to 10 weeks. This suggests that seedbanks are not formed.
Australian studies of willow ecology in local conditions are just beginning to be done. There is an extensive overseas scientific literature on Salix ecology and physiology which provides a useful background knowledge but which only occasionally address question relevant to issues Australia. Relying on overseas studies, even for same species, may be problematic as this assumes no physiological drift, no ecotypic development and no genetic sorting in species or their cultivars. The relevance and applicability of overseas studies to Australian conditions is a real issue that needs to be formally examined.
Environmental Threats The impact of willows on the riverine and riparian environment has not been documented. Stream ecologists have been concerned with the effects of willows on ecosystem functioning, suspecting that differences in leaf characteristics and timing of litterfall relative to the sclerophyllous and evergreen native trees have altered riverine carbon dynamics and hence food-web characteristics. Their simpler chemical structure means 110 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Species Profiles willow leaves decompose faster than do sclerophyllous myrtaceous native trees, and possibly due to different processes, eg abrasion rather than by microbial activity. The consequences for macro-invertebrate communities have not been thoroughly established; differences in invertebrate community abundance and diversity have been sought, but not always detected, suggesting that regional context is an important co- variate. The many other environmental changes caused by willows, due mainly to their dense canopy and to their habit of forming extensive stands, remain largely undocumented.
In small creeks and upland rivers, dense and continuous stands of shrub willows intrude into the active channel, thus reducing channel capacity and potentially leading to increased overbank flooding and scouring. In regulated rivers with reduced discharge, willows may colonise and stabilise sand bars. Both these result in changes to stream morphology. Willows also impact on plant species richness and riverine bio-diversity. Relative to native riparian vegetation, they form dense stands that are typically mono-specific and structurally simple, with no or little understorey. In addition, the thick willow canopy has a dual effect of forming dense shade, so stressing then excluding perennial plants and preventing seedlings from establishing, and also of creating a cooler more humid micro-climate. Changes to stream morphology, plant species richness, vegetation structure in the riparian zone have not been much documented so extent of the follow-on effects for riverine functioning and riparian ecology such as avifauna can only be roughly sketched out.
Recently studies have emphasised that one consequence is the introduction of a new seasonal dynamic. The deciduous habit of willows means not just dense shading in summer but greater light penetration to stream bed in winter, and hence a growing opportunity for fast-growing winter plant species, such as some algae.
Methods of Control Control of willows is well-understood and quite straightforward, and generally successful, except for girdling which generally encourages coppicing. Different options are available, allowing operators to match option with circumstance, tree age and site accessibility. Thus hand-pulling is suitable for young trees and juveniles, but older trees need to be cut and painted, removed or treated. Mechanical removal is effective on established trees but carries the risk of seeding viable branchlets and twigs further downstream so should be done only with specialist equipment. Herbicide control is effective, and can be applied as a foliage spray, injected under the bark, or painted immediately onto a cut stump to prevent regrowth. Repeated applications may be necessary for resistant species such as Grey Willow Salix cinerea. For all these, advice is available from agencies or equivalent natural resource management organisations, on procedures, techniques and hazards. Regional guides and policy documents are available.
Most advisory publications emphasise the importance of thinking beyond weed removal and eradication to consider also consequences for the river, replacement vegetation and impacts of the control operations. These publications also offer more strategic advice, on setting priorities, and on stream-lining operations, for example by developing targets based on acceptable low-risk species or population structure of a single gender, removed from the water way.
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7 Research Projects: Briefs
7.1 Methods The key output for the present project was to develop briefs to fill knowledge gaps concerning the impacts and management of pest flora and fauna species in the MDB, with particular emphasis on species that have invaded within and around aquatic ecosystems in the MDB. Biological invasions are now seen globally as one of the top threats to stream and lake ecosystems and require well-planned and coordinated management strategies. Most invaders within the MDB will have originated from outside of Australia, however, as species translocated from other areas of Australia can also be a potential problem, the issue of translocations is also addressed.
The funding of these projects should be seen as a coordinated MDBC program to tackle management of biological invasions.
Eighteen briefs have been developed (Table 10). The projects draw on the research priorities identified from pest fish and pest plant questionnaires (Sections 4 and 5) as well as several recent reviews in the literature (Arthington et al 1999, Arthington and McKenzie 1998, Koehn et al. 2000; CCCG 2000). The key outcomes of each brief also complement the objectives within existing management strategies within the MDB such as the Native Fish Management Strategy (Koehn and Nicol, in press) and issues identified within the Riverine Management Rehabilitation Scoping Study (CRCFE 1999) as well as broader management strategies (National Strategic Plans for Willows etc). The initiation of this research and management program will represent a more coordinated and adaptive approach to management of biological invasions in the MDB.
The projects represent a mix of research. Time-scales range from short (1-2 years), to medium (3-5 years) and long-term (>5 years). Importantly, the projects outline strategies for refining and coordinating management of biological invasions based on sound scientific methodologies and a generic risk analysis procedure. Many of the projects are targeted toward improving the knowledge base upon which decisions are made. Several of the projects have been divided into consecutive stages with each stage building on the outcome of the previous stage, as well as having applicable and relevant outcomes in their own right. Projects use catchment-based techniques to gather knowledge and develop methodologies for Basin-wide application.
7.2 Development and scope of projects The following points served to shape project development.
• Effective management of biological invasions can only occur if the spatial extent of an invasion is known. Yet our knowledge of the current and potential distribution of alien species is limited and fragmented. Addressing this essential knowledge gap has been given priority. • A major aim was to combine plant and fauna priorities where relevant and feasible. This was possible for some generic types of research. • Tasks and associated funding have been separated to facilitate resourcing by allowing project components to be funded individually. Thus some long-term projects are separated into discrete
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stages indicating how different steps may be funded over time. Once projects have been funded, an initial task of the project team would be to determine appropriate approaches to achieve objectives. Many of the project briefs provide suggestions for possible directions in approach. • Linking management, education and research was identified as the most effective means for coordinating approaches to pest management. In the absence of integration, management of biological invasions throughout the MDB tends to be seen as an overwhelming problem. • A multi-faceted approach with both broad and specific management objectives has been adopted.
The 18 project briefs fall into three broad categories, these are: (1) broad scale management and education, (2) research, and (3) management of particular problem species (see below).
Linkages between projects are shown in Figure 18. To achieve each of the project objectives a high degree of interaction should be fostered between the projects. To facilitate this we recommend the projects be overseen by a co-ordinator, whose role will be to implement and encourage inter-project communication whilst ensuring there minimal overlap of tasks. The coordinator will also be responsible for linkages across existing and planned environmental management programs, and will ensure that pest species and biological invasions are considered throughout the MDB. This is necessary as the problems due to and associated with pest species and biological invasions need to be integrated, rather than being treated separately, in environmental management.
Projects, their time-scale and approximate level of funding required are summarised in Table 10.
7.3 Outline and summary of projects 1). Broad scale management and education A fundamental first step in tackling the management of pest species is to ensure no further introductions to the Murray-Darling Basin.
As people are generally thought to be the main cause of the increasing rate of spread of many invaders, either on purpose or inadvertently, a comprehensive and effective education program is an essential component in achieving a reduction in successful invasions. This is addressed in Project 1. This education project should have direct links with more targeted management approaches for easily recognised high profile pests, such as carp and willows for which there is a general and strong community concern. By better understanding and managing widespread and well known pests then rapid response plans for high risk species such as tilapia can also be more effective. • Project 1 An Educational Strategy for Biological Invasions
There is a clear need to introduce a more cohesive approach to the management of biological invasions within the MDB. National approaches to pest management can be effective, whether focusing on multiple species as in WONS or on single species, as with the National Carp Task Force, and these nationally successful programs can be considered as a useful model for large catchments such as the Basin. In the case of single species management, this model could be broadened to address other priority pest species (Project 2). The charter of these groups could also be centred on an agreed rapid response plan (Project 3) and protocol for each occasion when a pest fish species is detected within the MDB.
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An important component of pest species management will be to further improve the communication and linkages between managers, researchers and stakeholders who undertake control and management programs (Project 4). If communication and experience can be better shared then there is a strong chance that more efficient pest management strategies will be progressively built and integrated, based on sound evidence and experience. These issues are addressed specifically for weeds in Project 5. Project 7 addresses the awareness and implementation of translocation and distribution policy and legislation within the MDB, recognising that many species translocations occur both deliberately and accidentally. There is also an urgent need to develop a species alert list, from a generic risk assessment process (Project 7) to validate and manage new pest incursions. • Project 2 A Generic Framework for Managing Biological Invasions • Project 3 A Rapid Response System for New Species Introductions • Project 4 A Co-ordinated Approach to Managing Programs for Controlling Biological Invasions • Project 5 Toward Improved Water Quality and Biodiversity through Integrated Weed Management in River Ecosystems • Project 6 A Review of Translocated Species and their Distribution • Project 7 Risk Assessment for Exotic and Alien Flora and Fauna.
2). Species management Development of species-specific management plans and on-ground control techniques will be vital for transfer of knowledge and technology between stakeholder groups (Projects 8-13). There are several priority invading pest species which are widespread and abundant across the MDB or have the potential to be so. There is a high recognition of the problems associated with these species in the general public and in some cases significant funds are allocated to their control each year. There are a number of promising techniques that have been recommended or trialed in the past decade but have not been broadly applied in a range of habitats. It is important that community groups become involved in practical management of invasive pests, for species such as carp, to gain an understanding and ownership of river restoration (Project 13).
• Project 8 Addressing Barriers and Knowledge Gaps crucial for effective Willow Management in south-eastern Australia • Project 9 Lippia as a Problem species in the riparian Zone and on Floodplains • Project 10 Integrated Control of Blackberry • Project 11 Integrated Management of Alligator Weed • Project 12 Research and Management of Gambusia • Project 13 Testing the Effectiveness of Carp Eradication and Control Techniques
3). Research There are also a number of priorities for research that does not specifically focus on single species and often relates to many of the more anecdotal impacts of biological invasions. These priorities also recognise that there are key knowledge gaps which must be filled before effective management can be undertaken based on the best scientific information. For example, there is an urgent need for broad-scale surveys to validate the
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Project 14 Determination of the Distribution of Alien Species Project 15 Assessment of Ecological Impacts of Alien and Exotic Species Project 16 Research and Management of Exotic Pathogens Project 17 Investigation of Potential Biological Control Technologies for Alien and Exotic Species Project 18 Assessment of the Effectiveness of Habitat Restoration as a Method for Controlling Biological Invasions.
7.4 Research Project Briefs The details of all research projects (Table 10) are provided in sections 7.4.1 to 7.4.18 and follow the format specified by the Murray-Darling Basin Commission. Each project is placed in the context of how it addresses key management areas within the Riverine Environment Sub-Program (MDBC 2000). Project objectives and key tasks are indicated, as are anticipated products and outcomes, opportunities for linkage, collaboration and end-user involvement and mechanisms for transfer and adoption. Estimated cost and duration for each project are provided, some of which include an upper and lower scale. Estimates are broadly based on a $100 000/person/year and $120 000/person/year where field expenses are included.
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Table 10: Summary of projects Project Project Title Time Scale* Scope Funding 1 An educational strategy for biological Short Term Basin-wide $300 K invasions Education 2 A generic framework for managing Short Term Basin-wide $120 K biological invasions Management 3 A rapid response system for new Short Term Basin-wide $120 K species introductions Management 4 A coordinated approach to managing Short Term Basin-wide Part A $250 K programs for controlling biological Management Part B $150 K invasions Part C $160 K 5 Towards improved water quality and Medium Term Basin-wide $120 K/y biodiversity through integrated weed Management management in riverine ecosystems 6 A review of translocated species and Short Term Basin-wide Part A $120 K their distribution Management Part B $120 K 7 Risk assessment for exotic and alien Medium Term Basin-wide Part A $120 K flora and fauna Management Part B $140 K 8 Addressing barriers and knowledge Medium to Basin-wide $235K/y for 5 y or gaps crucial for effective willow Long Term Management & longer management in south-eastern Australia Research 9 Lippia as a problem species in the Medium Term Basin-wide $150-200 K riparian zone and on floodplains Management & Research 10 Integrated control of blackberry Part A - Short Basin-wide Part A $90 K Term Management Part B $120 K/year (5 Part B - Long y) Term 11 Integrated management of alligator Medium Term Basin-wide $300 K weed Management 12 Research and management of Short to Long Basin-wide Six projects gambusia Term Management & Research 13 Testing the effectiveness of carp Medium Term Basin-wide $300 K/y for 3 y eradication and control techniques Management 14 Determination of the distribution of Medium to Basin-wide Stage 1 $150-300 K/y alien and exotic species Long Term Management & Stage 2 $100-150 K/y Research Stage 3 $100-150 K/y 15 Assessment of ecological impacts of Medium Term Targeted $100-150 K /y/project alien and exotic species Research 16 Research and management of exotic Medium Term Basin-wide $250 K pathogens Management & Research 17 Investigation of potential biological Short to Scoping Study Part A $150-200 K control technologies for alien and Medium Term Management & Part B $150-200 K exotic species Research 18 Assessment of the effectiveness of Short Term Basin-wide $150 K habitat restoration as a method for Management & controlling biological invasions Research * - S = short (1-2 years), M = medium (3-5 years), L = long (>5 years)
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Figure 18: Linkages between projects
Species Management Broadscale Management and Education
8. Willow 1. Education strategy 9. Lippia 2. Generic framework 10. Blackberry 3. Rapid response system 11. Alligatorweed PEST CO-ORDINATOR 4. Co-ordinated control programs 14. Gambusia 5. Integrated weed management 15. Carp 6. Translocation review
C
Research to fill Knowledge Gaps
14. Pest distribution 15. Ecological impacts 16. Pathogens 17. Biological control 18. Habitat rehabilitation
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7.4.1 Research Project Brief 1: An Educational Strategy for Biological Invasions
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • R0a) Transfer and adoption • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies The need for an educational program has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). They noted that people have some degree of understanding of ecological and economic effects of some pest species, but few recognise the connection between their own activities and the accelerating rate of invasions. Specifically there is a need for development and implementation of an invasive species education program to foster recognition and understanding in the wider community with particular reference to: • Methods of dispersal/transportation of invaders by human agents (e.g. aquarium trade, horticulture and nursery trade, recreational fishing groups, illegal pet trade) • The importance of the public’s role in the introduction and spread of invasive species (e.g. deliberate or accidental translocations through dumping of weeds and aquarium animals, movements of vehicles and boats) • Ecological, social and economic impacts of invading species (e.g. predation, competition and hybridisation with native species, habitat alteration, production losses in industry, vectors of disease, cost of control, decreased water quality and availability, flooding) • Differing potential for invading species to develop into pests and/or have detrimental impacts (e.g opportunistic invading species taking advantage of altered/disturbed habitats, invading species being constrained by biotic and physical factors which limit or negate their establishment). This highlights the need for risk assessment as a means of identifying key species to target in educational packages. • Some invaders that have not yet become established in Australia can have potentially disastrous ecological, economic and social effects and eradication warrants a coordinated rapid response approach (e.g. candidate species may include a fish, tilapia which has already been found in Queensland, or the Zebra Mussel which to our knowledge has not yet reached Australia, and the plants Salvinia and Senegal tea that have already been found in several locations). Education packages need to highlight these cases to emphasise the seriousness of invasive species, their impacts and indicate methods of control. • The observed connection between environmental degradation, disturbance and invasion success i.e. biological invasions in degraded and disturbed habitats can be facilitated by the disturbance rather than being a cause of the problem. Addressing factors that cause degradation (e.g. clearing of vegetation, unfenced grazing, desnagging, runoff) are important within an overall education program and may be fruitful in the management of invasive species. Consideration of biological invasions must form an integral component of any environmental management program such as rehabilitation programs undertaken in the MDB. • Control and eradication programs can be successful given effective technology, adequate resources and community support and require cooperation between groups involved. Highlighting these successes in
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educational material ensures positive messages are generated therefore encouraging support from the wider community.
This education project will address key management issues, strategies and policies in order to develop a coordinated educational strategy for the MDB. This would include educational material on aquatic and riparian plants and animal groups (i.e. invertebrates, fish, reptiles and amphibians) that can invade riverine environments. There are significant differences in public awareness amongst these groups and the impacts of their activities on the aquatic environment, due to differences in issues, impacts, perceptions, interests, available information and misunderstandings. While some invaders e.g. carp, tilapia, blackberry and willows, have been the focus of educational and control campaigns, little or no information is available on other invasive species such as the snails (e.g. Physa acuta, Pseudosuccinea columella, Potamopyrgus antipodarum) and various ornamental plants and animals. These differences can in part be attributed to differing commercial, agricultural and recreational interests e.g. agricultural weeds become a priority due to production losses and carp are a priority due to impacts on recreational and commercial fishing as well as water quality issues. Invertebrates may be overlooked due to their small size, relative ‘invisibility’ and perceived unimportance compared to larger species such as carp. Policy and associate research have been more directed to those areas of particular economic interest that also perpetuates this situation. General misunderstandings of particular aspects of invasion biology may arise through misinformation, lack of education (e.g. many people believe trout is native), and confusion between native and introduced species that look similar (e.g. alligator weed and lesser joyweed, parrot's feather and native milfoils). This emphasises the need for any MBD educational packages to reflect these differences in public awareness of invading species and packages need to involve a broad spectrum of approaches that reflect the knowledge base and key issues relevant to target groups while recognising and addressing key misunderstandings.
There is also a need to recognise barriers to understanding the detrimental aspects of pest species and to try to tackle these complex social issues. A major barrier is the public’s perception and understanding of what constitutes an alien species and this also serves to highlight the conflict of interests in the broader community. For example, trout are considered a valuable angling and commercial fish while some ethnic groups value carp as part of cultural tradition. This can lead to the problem of generating mixed messages such as those created by a recent article on the negative impacts of Koi carp in New Zealand that also referred to beneficial angling characteristics of this species. Thus educational approaches need to understand and incorporate the range of values held by the public, while focusing on educating them about potential detrimental impacts of alien species.
All educational material must be accessible in a variety of forms to reach all identified target groups e.g. brochures, booklets, posters, activity and resource kits for schools, media stories (current affairs, ABC Landline, newspaper and radio articles). The material also needs to have a MDB context that can provide comprehensive information at a basin level as well as more specific state-oriented information. This information could include an invasive species resource guide (e.g. Weed Navigator 1998) on the internet and possible as hard copy as a reference tool for invasive species within the MDB. The project will review existing information concerning biological invasions in the MDB and build on successful available educational material e.g. Queensland DPI, Gould League of Victoria and NSW (activity kits and books), Victoria DNRE, the Australian Weeds CRC. In order not to overwhelm the public with huge lists of invading species which could provide an impression that no advances have been made, there is a 120 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
need to target a selection of key species that have been carefully chosen to reflect what can be done, what has already been done and which actions will bring the best results.
Improving the public’s understanding of biological invasions and increasing their awareness of alien species can have added benefits e.g. the public can provide information on the location of pest species for which our knowledge is limited. This is of value for species which are still actively spreading in distribution and an understanding of their current distribution could assist in targeted management actions including monitoring and control. The program may be implemented along the lines of successful state-orientated programs such as Waterwatch and be coordinated throughout the MDB as a ‘Pestwatch’ Program and included as a component of current projects undertaken within the MDB. There is also great potential for involvement of the public in actively participating in the control of invasive species through modification of community attitudes and activities. The most important component in modifying attitudes involves educating the public on the impacts of invading species on the natural environment and the direct and indirect effects on their own lifestyles. Activities that can be modified include the use of pest species as bait, release of aquarium fish and plants, dumping of rubbish and garden waste, washing of machinery, boats, trailers and nets, not returning exotics to water when fishing, and protection of riverine environments.
3. Project Objectives • To increase the awareness of the general public, key stakeholder and interest groups, landholders, catchment management authorities, school students etc of the issue of biological invasions in riverine environments within the MDB. This includes factors that enhance their success, their detrimental impacts and what pre-emptive management and control methods can be undertaken. • To minimise any potential role the public and stakeholders may have in the introduction and/or spread of exotic species e.g. to modify public behaviour • To enable the community to provide information on the location of key current and potential alien species which can assist in the management and control of these species. • To monitor the success of education campaigns through evaluation programs.
4. Key Tasks • To review existing information concerning alien species within the MDB • To determine the range of end user and community groups which an educational program needs to target • To identify potential barriers in educating particular groups (e.g. due to social and/or cultural views where alien species are not considered ‘pests’ or detrimental) and develop appropriate methods to address these issues and effectively disseminate information. • To identify key misunderstandings and knowledge gaps concerning biological invasions including initial introduction of alien species, their spread, potential impacts and available methods of control. • To determine what information needs to be disseminated to the range of target groups • To develop material for the general public, school students and other interest and stakeholder groups to improve their understanding and identification of the current and potential alien species within the MDB. This includes issues relating to introduction and spread, impacts on the aquatic environment in association with other degrading processes, and the public’s role in minimising the introduction
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and/or spread of exotic species. The material would include a component to ensure that the public is able to correctly identify alien species or have contacts for expert identification, and highlight cases where pest species could be confused with native species. The program would be designed to ensure urgent information on current or potential alien species could be incorporated to allow for a fast and effective response to emerging problems within the MDB. This could include the development of advisory material on how to collect suspect species and what to do with it (e.g. how to preserve, who to contact etc) to ensure an appropriate identification. • To develop programs aimed at fostering a sense of ownership and encourage active involvement of these groups in preventing introductions and spread, and to reduce the impacts of biological invasions (e.g. knowledge generation, behaviour modification, habitat rehabilitation), particularly by use of pre-emptive measures such as animal and weed hygiene measures • To facilitate the public providing information on the location of key current and potential alien species, as part of a coordinated program. As well as facilitating knowledge generation and community ownership, such a program would highlight species for which we require distributional information. An improved understanding of the distribution of particular species, particularly those with limited distributional information such as some fish (e.g. tilapia and weatherloach), some species of snails (e.g. Physa acuta, Pseudosuccinea columella, Potamopyrgus antipodarum) will potentially assist in determining and implementing appropriate management and control programs and restricting further spread.
5. Anticipated Products • A coordinated educational program for current and potential alien species within the MDB • Information packages designed for interest groups - brochures, booklets, posters, study packs, website information, database of resources and contacts, talks, displays, stickers, signs, cd roms • A coordinated media campaign – television, newspaper and radio advertisements
6. Anticipated Outcomes • Improved understanding within the general public of how and why particular species are identified as ‘pests’ by government departments. • Increased public awareness of biological invasions within the MDB, including factors that lead to the success and spread of alien species, their impact on the environment and the role the public can play in minimising their introduction and spread. • Increased public involvement and ownership of pest species issue. • Improved coordination of alien species information across relevant government agencies within the MDB, as part of an integrated management approach to biological invasions. • Improved appreciation within government agencies and the general public of the value and importance of continuing education concerning biological invasions. • Increased awareness of the importance of including biological invasions as an integral part of MDB projects e.g. river rehabilitation
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7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) The need for an educational program has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). Managing the threats of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration This project has a strong potential for extensive linkages and collaboration between numerous groups. These include key federal government groups, state natural resource agencies, river management committees, catchment management authorities, councils, experts in invasive species, state weed societies, fishing groups, aquatic recreational groups, state education departments, conservation groups, research groups, universities, social researchers, aquaculture groups, aquarium trade, irrigators and general interest groups etc.
9. Opportunities for end-user involvement Those groups identified above represent the wide range of end-users who will benefit from a comprehensive educational program concerning biological invasions within the MDB. Their involvement will be sought in a variety of ways, particularly in relation to what information needs to be disseminated, key misunderstandings and knowledge gaps concerning biological invasions and their management, potential barriers to education, methods of fostering ownership, participation in preventing introductions and spread of pest species and providing distributional information.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess the most appropriate methods for disseminating education packages to various groups within the community • Steering committee would include appropriate representatives in order to determine priority education areas and the most effective approach in disseminating education packages to the wider community • Dissemination of a wide variety of information to wide range of end users. Dissemination of information as a comprehensive educational program is the key aim and output of this project.
11. Estimated cost and duration Short Term = 2 years Cost = $300 000 This cost may increase depending on the costs associated in producing particular material.
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7.4.2 Research Project Brief 2: A Generic Framework for Managing Biological Invasions
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2a) Capacity building and engagement
2. Context, and how this addresses key management issue(s), strategies or policies The establishment of the National Carp Task Force in 1996 as a result of public interest and pressure has promoted a more coordinated approach and national focus on carp control in Australia. The Task Force has membership from Commonwealth, State and Territory agencies with an interest in carp, researchers, recreational and commercial fishers and local government. It has enabled consolidation and focus of community energy in relation to management of this invasive pest species in Australia, and has been able to gain political support to influence decision-making. The aim of the Task Force is to eradicate carp from all Australian aquatic habitats through a strategic action plan that promotes coordinated research, provides good information, explores commercial opportunities and seeks complementary legislation (Koehn et al. 2000). It highlights the need to focus on a natural resource management strategy using pest management principles. The Task Force has developed an action plan which includes research, information, commercial exploitation and legislation objectives. Information is disseminated to the public and interest groups via a web page, regular newsletters, a database for carp records as well as widely available posters and brochures. These have helped to highlight the issue of carp within the broad community.
There is, however, a clear potential to broaden this successful approach for management of other alien fish species, in association with the public within the MDB. For example, a Biological Invasion Task Force with action plans for a suite of alien fish species, as well as those that have a high risk of introduction and establishment (such as Tilapia), would enable better coordination of management of biological invasions in the MDB.
3. Project Objectives • To develop a generic approach to establishing Biological Invasion Task Forces to enable a coordinated approach and community focus to control key invaders within the MDB.
4. Key Tasks • To use the National Carp Task Force as a model for the development of a generic Biological Invasion Task Force to enable a coordinated approach and community focus to control of key alien species within the MDB. • Review the National Carp Task Force to determine the levels of success in achieving a range of activities undertaken by the group. • Establish the key roles of Biological Invasion Task Forces including the setting of priorities, including as required the establishment of species specific task forces and recommendations for management, developing action plans which include research, information, commercial
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opportunities and legislative objectives. Activities which the Biological Invasion Task Forces could undertake could include forums to provide information and feedback to the community. • Establish a protocol to identify appropriate participants to be involved in key Biological Invasion Task Forces. They should include appropriate representatives from the community, stakeholders, science and government. • Identify those key species which would benefit from the establishment of a Biological Invasion Task Force. • Ensure that representatives from the generic Biological Invasion Task Force are included on steering committees for all related pest projects which occur within the MDB. • Develop a framework for information dissemination. This should identify the range of appropriate techniques for the identified range of target audiences. It should provide regular updates on activities, research and management within each state and in a basin-wide context, their findings, successes and failures, future directions etc. This may include the establishment of a website through the MDBC website.
5. Anticipated Products • A generic framework for establishment of Biological Invasion Task Forces within the MDB. • A coordinated information package easily accessible to the general public and interest groups concerning Biological Invasion Task Forces, their roles, achievements etc.
6. Anticipated Outcomes • A coordinated approach and increased community focus to control key alien species within the MDB. • An improved understanding of the general public concerning the management of key alien species and their role in the management and control of these species.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of biological invasions to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientists and other experts involved in the research and management of alien species, and in particular the strong involvement of interest and community groups and the general public.
9. Opportunities for end-user involvement End-users involve key government bodies across the MDB, land and water management authorities, scientists and other experts involved in the research and management of alien species using biological control techniques, interest groups etc.
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10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating the results of the project within the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users in a range of formats which should provide regular updates on activities, research and management within each state and in a basin-wide context, their findings, successes and failures, future directions etc. This may include the establishment of a website through the MDBC website.
11. Estimated cost and duration Short Term = 1 year Cost = $120 000 Once appropriate Biological Invasion Task Forces are established, they will require ongoing operating funds.
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7.4.3 Research Project Brief 3: A Rapid Response System for New Species Introductions
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M1b) Natural resource management governance
2. Context, and how this addresses key management issue(s), strategies or policies There are national regulations concerning the importation of exotic species into Australia, as well as a range of controls concerning the spread and release of species into waterways within the MDB. In addition there are lists of species that have not yet arrived, escaped or become established in Australia, but which may be particularly likely to in the near future (e.g. AQIS lists). However, there is always the potential that species that are not currently present within the country as well as those already occurring within Australia (e.g. in the aquarium and nursery trades), will be deliberately or accidentally released into the wild.
Given the potential for alien and exotic species to have significant detrimental impacts on the aquatic environment, there is a clear priority to attempt to identify and if possible prevent new introductions resulting in the establishment of self-sustaining populations. The development of a rapid identification and response system is needed to ensure that a standard plan is put into place as soon as there is a report of a new exotic species occurring within or near the MDB (whether this record is confirmed or suggested). This process will ensure that the likelihood of a successful eradication of a newly introduced species is maximised and that we have a chance to manage this threat promptly.
The need for a standard response plan has already been recognised in parts of Australia. For example, the 'Queensland Freshwater Strategy for the Control of Exotic Pest Fish' (DPI 2001) includes the development of a contingency plan response system to prevent new infestations. It emphasises the need for a clear plan of action if new infestations are detected, and notes that responses to date have often been inadequate. Similar plans for incursions of new weed species have been adopted in NSW, Tasmania and Victoria (NSW Weeds Strategy, Tasmania Weed Alert Network, Victorian Weed Rapid Response Plan). A workshop was recently run to address the possible introduction of tilapia in the MDB Queensland; this reviewed a range of issues including existing knowledge of the biology of tilapia, potential impacts, characteristics of waterways it may have invaded, factors which may block the development and implementation of a contingency plan, identification of an appropriate response team, as well as a list of required tasks in the immediate, intermediate and longer term, including the type of education required. A structured generic approach can be used to develop contingency response plans for action that should be taken in response to reports of new arrivals, releases or discoveries of established populations of exotic and alien species. Such an approach will identify a standard set of procedures to be put in place immediately, including identifying who should be consulted and involved in management as well as the identification and implementation of management actions. Targeted actions should then focus on dealing with the outbreak before the species spreads and produces self-sustaining populations.
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3. Project Objectives • To establish a protocol for a response plan to implement whenever there is a possibility of a new introduction of an alien or exotic species within the MDB. • To facilitate the implementation of this standard response plan by relevant authorities within the MDB to eradicate alien or exotic species before they establish self-sustaining populations. • To develop methodologies for evaluating the success or failure of a given response plan and use this data to improve future response plans. • To instigate a rapid response process within the MDB, with locally trained personnel.
4. Key Tasks • Review existing approaches to managing known or suspected new introductions of alien and exotic species within Australia and overseas (e.g. New Zealand). This could include an assessment of the successes and possible failures in the range of approaches. Key representatives experienced in different approaches should be contacted for advice. • Explore the use of, and if appropriate contribute to, global alien species initiatives and databases to provide information on particular alien species, their ecological requirements their potential impacts and potential control measures. • Identify relevant government bodies, both on a national and international level, land and water management authorities, councils, experts from research institutes, interest and user groups (e.g. aquarium, aquaculture trade) who should be involved. • Liaise with these individuals and groups in the development of the appropriate protocol. Comments could be sought via a questionnaire to identify peoples' views of successful and unsuccessful approaches and factors that need to be considered for the protocol. • Develop an appropriate protocol to manage known or suspected new introductions of alien and exotic species within the MDB. This should include identification of all key components needed for a standard response plan. These may include education, biology of species, known and potential impacts and factors which will influence its spread and success, identification of appropriate response team, factors that may block the development and implementation of a plan, tasks in the immediate, intermediate and longer term, appropriate methodology to collect specimens for identification etc. • Trial the protocol at a workshop, using a mock scenario. The species selected for the trial could be a species of significant current concern which has a high potential of being introduced within the MDB. • Develop a final version of the protocol following the workshop, incorporating modifications to the protocol if they have been identified as necessary. • Circulate the standard protocol to key government bodies, land and water management authorities, experts, interest and user groups. Promote the protocol to ensure all appropriate individuals and groups are aware of its value and existence. This should include the identification of most appropriate methods of disseminating this information. The methodology used for programs such as 'Fishwatch' should be considered for their applicability.
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• Identify key representatives who would be responsible within each state and in a basin-wide context for implementing a standard response plan. Formalise their responsibilities in the event of a possible new infestation. • Train local representatives and officers in their role and responsibility in responding to new and emerging pests in their region. • Develop a procedure to monitor the effectiveness of implementing a standard response plan.
5. Anticipated Products • A standard generic response plan to deal with new and possible infestations of alien and exotic species within the MDB. • A method for evaluating and updating the standard response plan. • Trained local representatives and officers aware of their roles and responsibility in responding to new and emerging pest issues.
6. Anticipated Outcomes • A coordinated response to dealing with new and possible infestations of alien and exotic species across all states within the MDB and basin-wide • An efficient response plan, with an evaluating and updating phase, which aims to minimise the potential for any new infestations to lead to the establishment of self-sustaining feral populations • An improved understanding within key government bodies, land and water management authorities, experts, interest and user groups as to the methods of dealing with potential and new infestations of alien and exotic species. • A rapid response to high priority new pests within the MDB.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. This is particularly important because pest species have potential economic, social and/or ecological impacts.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, land and water management authorities, scientific experts, interest and user groups etc. International linkages are also important to draw on the knowledge gained about managing early detection of particular pest species elsewhere.
9. Opportunities for end-user involvement End-users involve key government bodies, land and water management authorities, experts, interest and user groups. They will be involved in all aspects of the project where direct liaison will be undertaken to determine the range of approaches to dealing with potential and new pest infestations, the identification of an appropriate standard response plan and its implementation.
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10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating results of the project with the community. • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users, including promotional material. • 11. Estimated cost and duration Short Term = 1 year Cost = $120 000 (nb: training components would increase these costs)
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7.4.4 Research Project Brief 4: A Coordinated Approach to Managing Programs for Controlling Biological Invasions
1. Key Management Issue(s) (as identified in the RESP) • R4a) Re-establishing populations and communities • R4b) Managing floodplain, wetland and riparian habitats • R4c) Managing instream and estuarine habitats • R4d) Managing threats to communities and habitats • R0a) Transfer and adoption • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies This project incorporates several components into a coordinated approach to controlling biological invasions within the MDB: a) an accessible information package for managers responsible for control of biological invasions b) the establishment of a standard set of procedures to assess the effectiveness of control programs and c) the development of a database to incorporate this information.
There is some potential for Part A and Part B to be funded as individual projects, although Part C is closely linked to both these components.
A) An accessible information package for managers responsible for control of biological invasions A range of public authorities are responsible for the management of waterways within the MDB and across Australia. This includes the control and/or management of alien species for a range of reasons, including environmental, economic and social. For alien species control, the amount of information and resources available to managers varies significantly. Thus control and management programs often tend to be a highly variable in their approach, methodology and success. The lack of a consistent set of guidelines for best management practice and availability of relevant information means that many control programs may not be undertaken effectively and efficiently, using appropriate reasoning and the most up-to-date information.
There is a clear need to develop an information package for managers concerning the range of techniques available for the control of biological invasions. Such an information package should include a review of each control technique including details of the costs and benefits of each technique, their applicability and practicality for a range of areas and conditions, relevant controls and legislation relating to techniques, and standard methodology. It should also provide an important guide to available knowledge and references including control programs which have already been undertaken and their results, as well as contact details for relevant government bodies and individuals experienced in control of biological invasions. Such an information package would facilitate a far more coordinated approach to management and control of alien species within the MDB which would be more effective and efficient and allow for
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transfer of information and technology between appropriate people. This information would provide an effective decision support tool, providing indications of where and how particular methodologies should be applied. Improved liaison and information transfer would enable better planning of control programs, building on the existing experience of managers. It may also generate interest and commitment from stakeholders.
B) The establishment of a standard set of procedures to assess the effectiveness of these control programs There would be a clear benefit in having a more coordinated approach to control programs for alien species within the MDB. The development of a standard protocol for managers to follow when undertaking control programs would enable their effectiveness to be assessed in a more quantified way than is currently occurring. Recognising that control programs will vary in their size and complexity, several protocols could be developed and applied to different circumstances. This could include consideration of the inclusion of community monitoring and control programs in association with industry such as professional fishers.
A standard protocol could include specific targets which should be aimed for (e.g. eradication of a species, improvement in environmental conditions such as increased native species diversity and abundance) which will assist managers in clarifying their aims. The results of control programs, whether entirely or partly successful or unsuccessful, are an important source of information in the development of more efficient programs.
C) The development of a database to incorporate this information. This project includes the development of a database to incorporate the above information concerning field control programs and monitoring their success. Those involved in control programs could fill out a standard data sheet (Part B) which could include information such as methodology, specific site conditions and results of the programs which could be incorporated into the database. Thus anyone contemplating undertaking a control program could base their decisions on the available guide to control programs (Part A) and the results of control programs already undertaken (Part B). For example, a local council may be contemplating controlling gambusia in a particular habitat. By reviewing the database, they would become familiar with all their options, appropriate procedures to follow and possible likelihood of success. They would be able to contact all relevant people to obtain further advice.
The establishment of a database via the MDBC website would maximise the accessibility of this information. A procedure would need to be set in place concerning how information is entered and maintained on the database. Many managers may not have the time or inclination to review numerous scientific papers and so the provision of information in a suitable format which is easily accessible is important. The use of a standardised protocol will increase the awareness of a range of managers to include a consistent form of evaluation of control programs, which will depend on particular situations.
The overall project would develop a wide range of information relating to control programs for biological invasions in a variety of formats. These would include the MDBC website with specific information packages about control techniques (e.g. fact sheets), downloadable forms to fill in to document and evaluate control programs, a database to scrutinise for information as well as incorporate 132 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
information, informal chatrooms for advice, contacts and links to experts and key government bodies, researchers etc, directions on where to obtain more information such as scientific reports and articles etc. Such a system will also potentially make the management of new alien species easier to deal with.
3. Project Objectives • To develop an easily accessible information package for managers, as well as other interest and user groups responsible for control of biological invasions within the MDB. • To establish a standard set of reporting procedures for managers to assess the effectiveness of control programs in order to facilitate a coordinated approach to control and management programs for alien species within the MDB. • To develop a database to store information on control and management programs for alien species within the MDB. • To improve communication between management projects specifically dealing with biological invasions within the MDB.
4. Key Tasks Project A - Information Packages • Review existing and potential methods of controlling alien species within Australia and overseas. • Contact key experts, managers, interest and user groups within Australia and overseas to obtain their advice concerning current and potential control methods. • Collate this information into an easily accessible information package for managers responsible for undertaking control programs within the MDB. • Identify the end-user needs as well as resources available to all relevant managers and others responsible for carrying out control programs. • Determine the most appropriate methods to disseminate this information, which may primarily involve the development of a web-based information source. • Develop this information package. It should include all relevant information on control techniques (i.e. costs and benefits of each technique, their applicability and practicality for a range of areas and conditions, relevant controls and State and Federal legislation relating to techniques, standard methodology, sources of additional information including scientific and management literature, key contacts for advice and requirements for approval etc.). This information package should ensure that those considering control programs can make informed decisions using all essential and relevant information and are able to integrate approaches to obtain maximum benefits. • Promote and publicise this information package to all relevant end-users. • Identify key government agencies and other relevant organisation who should participate in maintaining and contributing to this information package. A formal process should be put in place to ensure the package is kept up-to-date. • Ensure the information resource incorporates a feedback component to determine whether it is effective and achieves its goals. The resource should be monitored and assessed on an annual basis.
Part B - Standard Procedures for Control Programs • Review current control programs of biological invasions which occur within Australia and most specifically within the MDB.
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• Determine how a more coordinated approach could be developed for managers to follow when undertaking control programs to enable an quantified assessment of them. • Determine how this approach could include control and monitoring by community, interest and users (e.g. professional fishers). • Contact key experts, managers and interest groups involved in control programs to obtain their advice about how control programs could be monitored in a coordinated way. This should include identification of the needs and expectations of these groups, their commitments to monitoring control programs and how this process can be promoted and monitored. • Develop a series of standard protocols for monitoring the effectiveness of control programs. These should vary to correspond to control programs of different scales and intensities. • Determine a methodology to collate this information (as referred to in Part C) to enable a coordinated approach to assessing the effectiveness of control programs with the aim of developing more efficient programs. • Determine the most effective method of disseminating these standard protocols to end-users. • Promote and publicise these standard protocols to all relevant end-users. • Identify key government agencies and other relevant organisation who should participate in collating this information.
Part C - Database • Develop a database to incorporate information obtained from Part A and Part B. • Determine how this database should be maintained and kept up-to-date. • Promote and publicise the existence of the database which should include an explanation of how information can be added to it, and how it can be used by relevant managers, interest groups etc. • Review the effectiveness of the database, as well as the information provided from Part A and Part B, possibly on an annual basis.
5. Anticipated Products • A comprehensive information package for those involved in undertaking invading species control programs within the MDB. • Standard set of procedures for those involved in undertaking invading species control programs to enable quantitative monitoring of these programs to assess their effectiveness. • A database to document information on appropriate methods of controlling alien species and their effectiveness. • A publicity campaign to inform stakeholders of the information package, procedures, database and website.
6. Anticipated Outcomes • A coordinated approach to undertaking control programs of biological invasions within the MDB. • Improved linkages and information transfer between all groups involved in pest control programs within the MDB. • A consistent approach to monitoring the effectiveness of control programs within the MDB.
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• An improved recognition by all relevant user groups that control programs need to be monitored and reviewed to assess their effectiveness. • Better decision-making for all groups involved in controlling alien species within the MDB. • More efficient and effective control programs for alien species within the MDB.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientific experts, mangers, interest and user groups involved in the control and monitoring of pest species. International linkages will also be important to draw on the knowledge of control practices for biological invasions outside of Australia.
9. Opportunities for end-user involvement End-users include key government bodies, scientific experts, managers, interest and user groups involved in the control and monitoring of alien species, as well as the general public. End-users will participate in most aspects of the project where direct liaison will be undertaken to determine current control program practices and available knowledge concerning management of alien species.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating results of the project to the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users. This will include a comprehensive web-based information package, standard protocols for monitoring of control programs, and a database to document information relating to control programs. A key aim of the project is information dissemination.
11. Estimated cost and duration Part A Short-term = 1.5 years Cost = $250 000
Part B Short-term = 0.5-1 year Cost = $150 000
Part C Short-term = 1.5 years Cost = $160 000
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7.4.5 Research Project Brief 5: Towards Improved Water Quality and Biodiversity through Integrated Weed Management in Riverine Ecosystems
12. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats
13. Context, and how this addresses key management issue(s), strategies or policies Weed management within riparian zones is intrinsically difficult for the following reasons: downstream movement of weed propagules reduces the likelihood of long-term effective weed management, because of the persistent risk of re-invasion; physical removal risks destabilising banks before replacement vegetation establishes, operation of machinery can be difficult; and fire may not be possible or compatible with desirable plant species.
Use of herbicides may be essential for effective weed control, but proximity to watercourses means a high risk of inadvertent pollution directly or through drift with consequent environmental problems downstream. There is also the risk of direct toxic effects on non-target plants or animals and large masses of decaying weeds may reduce water quality. Few herbicides are registered in Australia for use on aquatic weeds, and most of these only in a restricted range of situations.
Weeds that occur close to watercourses are covered by many more herbicide registrations than truly aquatic weeds. In order to minimise downstream contamination, products do carry instructions to avoid contamination of watercourses. This precautionary approach places considerable responsibility on the user who may not be informed regarding the type and hence risks with different formulations. Hence there is confusion over how herbicides should be used in riparian zones; with the result that organisations and individuals develop their own practices in an uncoordinated way. It would help end-users to have clearly presented information workshops and training that assists them in meeting their legal obligations. Information on how different herbicide types behave in the environment and advice on appropriate equipment and application practices needs to be brought together in a readily available format, and training done with target and focus groups. This approach is expected to reveal a number of information gaps and specific questions on environmental behaviour of certain herbicides that may need to be resolved through additional research. These gaps would be the basis of recommendations.
3. Project Objectives • Update, collate and summarise relevant and useable information products to assist responsible herbicide use in riparian zones. • To identify and develop new herbicide treatments to assist the management of specific aquatic weeds. • Investigate new low input weed-management regimes to reduce riparian disturbance, allow tree recruitment and thus enhance or protect biodiversity.
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• Through workshops and surveys, identify specific priorities for research, extension and regulatory changes for riparian and aquatic herbicides. • Develop data sets on selected herbicides enabling registration or permitted use in riparian situations • Produce reports on the aquatic herbicides tested and submit herbicides for registration if appropriate. • Produce integrated management guides that incorporate updated information on herbicides for aquatic weeds. • Develop low impact control measures to reduce riparian disturbance, pollution and increase biodiversity. • Involve end users, key government bodies, land and water management authorities, experts, interest and user groups in determining the ranges of approaches of control of riparian and aquatic weeds.
5. Anticipated Products • A short publication containing practical information regarding the use of herbicides in riparian zones. • Integrated management guides that incorporate new uses for existing herbicides herbicide uses for aquatic weeds.
6. Anticipated Outcomes • Increased options for land managers within the MDB for sustainable control of riparian weeds • Minimised risk of downstream and non-target damage caused by inappropriate use of herbicides. • More information available for land managers on strategies and control of riparian and aquatic weeds
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. This is particularly important because pest species have potential economic, social and/or ecological impacts.
8. Opportunities for linkage or collaboration The CRC for Weed Management Systems has recently begun its second term and now has a nationwide focus on weed control. One of its core projects is weed control in riverine systems. The proposed project is a current project within the CRC for Weed Management Systems but additional input from the MDBC will see a much more robust program that will focus on the MDB. The other CRC participants will collaborate in identifying issues and conducting research on herbicides (especially Queensland Department of Natural Resources and Mining and NSW Agriculture) and in riparian tree recruitment studies (QDNRM, CSIRO Sustainable Ecosystems Division, University of New England). Other collaborators include CRC Freshwater Ecology, DNRE Vic Chemical Standards Branch, (other State equivalents) RMIT University, National Registration Authority, Avcare.
9. Opportunities for end-user involvement End-users involve CRC for key government bodies, land and water management authorities, experts, interest and user groups. They will be involved in all aspects of the project where direct liaison will be
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undertaken to determine the range of approaches to dealing with pest infestations, the identification of an appropriate standard response plan and its implementation.
10. Mechanisms for transfer and adoption • Liaise with MDBC education unit and stakeholders to ensure information material is in appropriate form for dissemination. Material can be in pamphlet, book, CD -Rom or Web page format. • Utilise other institutions, eg CRC Freshwater Ecology, DNRE Vic Chemical Standards Branch, (other State equivalents) RMIT University, National Registration Authority, Avcare to target end users and disseminate information.
11. Estimated cost and duration Medium Term = 3 years Cost = $120 000/year
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7.4.6 Research Project Brief 6: A Review of Translocated Species and Their Distribution
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • R0a) Transfer and adoption • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies Translocations include the movement of animal and plant species beyond their natural range and/or to areas within their natural range that have genetic stocks and/or populations that are distinct (MFFA 1999). Translocations may be deliberate or accidental and include stockings of waterways for recreation, release or escape of aquarium fish, snail and plant species, use of live bait and aquaculture systems. There are numerous examples of translocations of both native and introduced species within the MDB, both legally and illegally. Many translocations are considered beneficial by particular user groups e.g. in recreational stockings and fish enhancement programs.
The potential detrimental impacts of animal and plant translocations have only recently being recognised and considered. The 'National Strategy for the Conservation of Australia's Biological Diversity (DEST 1996) identifies the introduction and spread of alien species and the deliberate spread of native species outside their historical range as a threat to biodiversity. Translocations may be detrimental in relation to genetic changes to native populations including hybridisation, establishment of feral populations, environmental impacts including competition, predation and environmental modification, spread of diseases and parasites, hydrological and water quality effects, and translocation of other associated species such as attached parasites and weeds (MFFA 1999).
The past assessment of proposals for translocations have been undertaken in an ad hoc manner and have not used a standard set of guidelines. Following this recognition, 'A National Policy for the Translocation of Live Aquatic Organisms' was recently prepared by the Ministerial Council on Forestry, Fisheries and Aquaculture. This aimed to provide a consistent national framework to assess the potential risks associated with all proposals for translocation of live aquatic organisms. The 'Weeds of National Significance' initiative similarly provides a national framework for weed management. States within the MDB also have their own translocation and distribution policies for both animals and plants. It appears there is limited general awareness of the existence of a national policy and state policies concerning translocations, as well as issues associated with translocations, amongst user groups and relevant managers. This needs to be improved to ensure a consistent and responsible approach is taken to managing this issue.
3. Project Objectives • To review existing state and national animal translocation and plant distribution policies, specifically in relation to their implementation and effectiveness. • To identify the level of awareness within key interest and user groups and relevant government managers concerning translocation and distribution policy and legislation.
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• To identify priority issues concerning translocation and distribution of native and alien species within the MDB and how they should be managed. • To identify and implement methods of maximising the implementation and effectiveness of translocation and distribution policies.
4. Key Tasks • Review existing state and national translocation and distribution policies • Determine the awareness and implementation of both national and state policies by relevant government bodies and interest and user groups. This should involve direct liaison with these groups and development of a limited survey of these groups concerning their understanding of the issue of translocation and distribution and relevant policies and legislation. • Identify methods to increase awareness and implementation of policies and legislation as well as issues relating to translocation and develop suitable awareness programs. This could include formalising commitments to implementation, improved liaison and provision of educational material e.g. brochures, web-based information. • Review current and potential translocations and distribution of natives and introduced species within the MDB. • Identify priority issues in relation to translocation and distribution of native and introduced species. This could include existing risk assessment procedures. • Develop procedures to ensure priority translocation issues are managed in a consistent manner to limit any potential threats to the integrity of ecosystems • Develop a procedure to monitor the effectiveness of translocation and distribution policies within the MDB.
5. Anticipated Products • A comprehensive review of awareness and implementation of translocation and distribution policy and legislation within the MDB • A strategy to improve awareness and implementation of this policy and legislation • A priority list of translocation and distribution issues and species within the MDB • A consistent method of managing translocation and distribution issues within the MDB • An information package including material for the MDBC website explaining translocation and distribution policies and current programs within the MDB. • Identification and advisory brochures to assist industry and communities in minimising incursion risk.
6. Anticipated Outcomes • A more consistent approach to translocation and distribution policy and implementation in the MDB, including risk assessment and decision-making processes • An improved compliance to appropriate policies and legislation • An improved understanding of issues relating to translocation and distribution of native and alien species within the MDB within the general public, interest groups and relevant managers.
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• Implementation of consistent methods to address translocation and distribution issues to minimise adverse effects.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between federal and state government agencies involved in translocation and distribution issues including fisheries and agriculture departments and land and water management authorities. Interest and user groups involved will include angling groups, conservation groups, aquaculture and aquarium industry groups.
9. Opportunities for end-user involvement End-users include federal state government agencies and interest and user groups such as angling groups, conservation groups, gardening groups and aquaculture, nursery and aquarium industry groups. They will be involved in most aspects of the project where direct liaison will be undertaken to determine their level of awareness of national and state translocation and distribution policies and legislation, their views of priority issues and on the development of procedures to maximise the efficiency of management of translocation and distribution issues.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating results of the project with the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users, including educational material. This may include material for the MDBC website explaining translocation policies and current programs within the MDB.
11. Estimated cost and duration Translocation of Fauna Short Term = 1 year Cost = $120 000 Plant Distribution Short Term = 1 year Cost = $120 000
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7.4.7 Research Project Brief 7: Risk Assessment for Exotic and Alien Flora and Fauna
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2c) Knowledge management • M2d) Decision support systems for investing in economic, environmental and social outcomes
2. Context, and how this addresses key management issue(s), strategies or policies Over the past 200 years the native flora and fauna of the MDB have been augmented by introduction of exotic and alien species. For example, over 10 known exotic and alien fish and over 2000 introduced plant species have naturalised in Australia, many of which have formed self-sustaining populations in the MDB. The impacts of invasive species (e.g. carp, salvinia and willows) can often be severe and there are numerous examples of large-scale declines in biodiversity. Although these introductions have often had disastrous consequences for native biota in most cases the impacts of these species are unknown.
Successful management of biological invasions is dependent on making effective decisions about complex problems while making best use of resources. To estimate the threat of impacts by an exotic species on valued resources, ecological risk assessment and decision analysis use available information to simplify the decision-making process. Such systems can manipulate large amounts of unstructured information by breaking down variables into a hierarchical order. Judgements can then be made to determine the highest priority variables for effective management of the exotic invasion and weighted among environmental, social or economic values.
A variety of risk assessment techniques have been used to simulate and predict future trends for invasive flora and fauna populations in Australia. These assessments consider aspects such as the environmental tolerance, impacts, dispersal vectors, and competitive ability of the invasive species. However, to ensure that there is a rapid and cohesive response to all new invasive flora and fauna infestations, based on strong evidence, there is a need to develop a single risk assessment process for the MDB. The process is of particular value for high risk fish and plant species such as tilapia, sagittaria and lippia. The system should use a range of expert and stakeholder judgements to formalise the decision process and conduct a detailed risk assessment for current and potential invasive species, to prioritise species and areas of MDB for research and management.
3. Project Objectives • To develop a generic risk assessment and prioritisation processes for invasive flora and fauna that are present or have potential to invade the MDB. • To assess and prioritise the risk of particular invasive species and undertake an extension program for all priority species. • To prioritise work areas for action on biological invasions based on the social, economic and environmental values of the MDBC.
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4. Key Tasks • Review relevant literature and databases from Australia and overseas for recording invasive species infestations and their management. • Review the current risk assessment methodology used in Australia and overseas to prioritise invasive species for management. • Hold workshops with federal, state, regional and local land managers to determine the social, environment and economic values of MDB and prioritise threats to these values. • Hold several workshops to develop a risk assessment process for different taxonomic groups (flora and fauna) and processes with experts and stakeholders from a range of backgrounds including scientists, river managers, government agencies and community groups. • Evaluate the consistency of the risk assessment hierarchical process and through field experiments to validate this process. • Identify both key knowledge bases and gaps in the risk assessment process, which require further interrogation and/or research. • Identify the list of species to incorporate into the risk assessment process. • Conduct a detailed cost-benefit analysis of impacts and management strategies of priority invasive species, as determined by risk assessment, to the MDB. • Provide a comprehensive list of priority invasive species to policy officers, river manages and research agencies for use in evidence based resource allocation. • Provide risk assessment information for development of procedures for rapid responses to new incursions of invasive species, which have a high risk of establishment.
5. Anticipated Products • A comprehensive and transparent decision support system for analysing the risk of new and established alien flora and fauna species that allows a wide range of users to interpret the data using a set of tools developed by experts. • A more effective and evidence based methodology for resource allocation in the management of biological invasions within the MDB that provides an explicit method for integrating ecological, social and economic criteria into the decision-making process. • An agreed methodology for communicating the risk of invasive species between resource managers and stakeholders.
6. Anticipated Outcomes • A coordinated approach to prioritising alien species management in the MDB. • An improved understanding of the significance of the threat posed by present and potential invasive flora and fauna in the MDB. • Application of best management practice strategies to management of biological invasions in the MDB.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
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8. Opportunities for linkage or collaboration Decision support systems and risk analysis is a growing field. Many federal and state agencies, taskforces and activity groups (suck as the CRC for Weed Management systems, National Carp Taskforce, Agriculture and Natural resource departments) are interested or are developing risk assessment processes and should collaborate with the development of the MDB assessment process.
This project links closely with project 3 "A Rapid Response System for New Species Introductions", as all newly naturalised species should be assessed for their potential weediness.
9. Opportunities for end-user involvement The decision support system and risk assessment process should utilise input from the end users and land managers (such as resource managers, water management agencies, agricultural departments, Landcare groups, environmental departments) to determine high value areas of the MRDC. The outputs should be able to be reviewed by end users to ensure the project delivers suitable relevant information, databases and priority areas.
10. Mechanisms for transfer and adoption The Decision Support System, results and decision-making process need to be transparent to allow end users to be able to review the process as well as be suitable to be displayed over the internet.
The MDBC education unit would oversee the transfer of information to ensure the appropriate methods of knowledge transfer occurs to the community.
The steering committee should have representatives of end-users (land managers, state fisheries agencies, stakeholders etc) and interested resource users.
11. Estimated cost and duration Medium Term = 2 years • Development of exotic and invasive flora and fauna decision support systems and risk analysis = 1 year • Review, extension and knowledge transfer = 1 year Costs can be separated into flora and fauna components or considered as a combined project. Combining the two components will save some costs since some tasks are applicable to both (e.g. assessment of land value) Flora $140 000 Fauna $120 000 Combined $240 000
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7.4.8 Research Project Brief 8: Addressing Barriers and Knowledge Gaps Crucial for Effective Willow Management in south-eastern Australia
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies Willows (Salix – with some 32 naturalised taxa, including primary hybrids) are amongst the worst riparian and wetland weeds in temperate Australia. All taxa (except S. babylonica, S. x calodendron and S. x reichardtii) are listed as Weeds of National Significance. These trees and shrubs were deliberately introduced in the 1800s and 1900s for a range of purposes, notably basket-making materials, cricket bat production, stream stabilisation, ornament and shelter. Willows continue to be predominantly used for a range of purposes, including stream stabilisation. Over 45 taxa are available in the nursery trade. Willows now occupy thousands of kilometres of streams, and numerous off-stream wetlands, from sea level to alpine locations. Victoria, Tasmania, New South Wales and the Australian Capital Territory have the largest current infestations, but only a fraction of potential habitat has been occupied in Australia. Dispersal is by vegetative means (fragmented stems) and by seed; production of wind-borne seed enables willows to be dispersed great distances and these species threaten most temperate, non-saline wetlands. Willows threaten to destroy biodiversity and the amenity values of invaded sites, and have already caused massive alterations to streams with blockages, increased flooding, erosion and channel realignments as well as destruction of infrastructure. They also have high water use. Millions of dollars are annually spent on willow control using chemical and/or mechanical techniques in south-eastern Australia. Mechanical and chemical control techniques are well understood and willows are relatively easy to kill. However, continuing follow-up control for at least three years is essential. Biological control offers considerable potential and a review of potential agents (invertebrates and pathogens) has recently been completed in Victoria.
A new program to address gaps in our understanding of the impact of willows on riverine ecosystems in Victoria is being developed by NRE as part of its contribution to the new CRC for Australian Weed Management. As identified in the National Strategic Plan for Willows (NSP Willows), there are critical areas requiring applied research to assist water and conservation managers to remove or control willows and restore native vegetation. Potentially this research could be partially supported by funds applied to the National Weeds Program (NHT) however as with other large-scale weeds only a co-operative effort will result in success. Long-term funding by organisations such as MDBC is essential to provide stability and attract short-term funding from other sources.
3. Project Objectives • To organise and conduct a major symposium/ workshop on best-bet management practices for willows {meets action in NSP Willows 2.1.6 & 2.2.4}.
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• To assess and evaluate current knowledge on willow control and management methods (including extension material), identify gaps for future research and suggest improvements to communication amongst key land managers and stakeholders {meets action in NSP Willows 2.1.2, 2.2.5 & 2.4.1}. • To trial post willow-removal revegetation strategies suitable for different environments and vegetation types {meets action in NSP Willows 2.1.2 &2.2.5}. • To make off-label herbicide recommendations, and identify opportunities for research into new herbicide treatments to assist in the control and eradication of willows {meets action in NSP Willows 2.1.3, 2.1.4 & 2.2.6}. • To develop a project on biological control for priority willows (Salix spp.) naturalised in south eastern Australia and to implement it {meets action in NSP Willows 2.1.2 & 2.2.4} • To refine and conduct risk assessment modelling for new and emerging willows species and develop an early detection and rapid response mechanism {meets action in NSP Willows 2.1.1 & 2.1.2} • To establish training courses in detection and rapid response for regional staff {meets action in NSP Willows 2.1.1 & 2.1.2}. • To develop best-bet management demonstration sites (using latest technologies) in Victoria and liaise with relevant agencies in other States to include one of their sites in a National network of demonstration sites {meets action in NSP Willows 2.1.6, 2.2.1 & 22.4}. • To monitor and document effectiveness of techniques at best-bet management sites in all south- eastern States {meets action in NSP Willows 2.1}. • To develop and implement a broad public communication strategy {meets action in NSP Willows 2.4.1}
4. Key Tasks • Plan and conduct Symposium and workshop • Assess and evaluate current control methods and establish best-practice • Prepare National Communications Plan through consultation with partners, stakeholders and States • Assess weed potential of non-naturalised Salix spp. • Assess risks of most dangerous Salix spp. • Develop rapid-response protocols for most dangerous Salix spp. • Recommend Salix spp. for declaration as noxious • Provide specialist off-label herbicide advice as required • Liaise on demonstration sites with other State projects • Establish best-bet management demonstration sites in Victoria • Stable revegetation practices at demonstration sites • Report to project partners on the feasibility of biological control of willows and publish results • Plan overseas studies on selected biocontrol targets based on feasibility recommendations • Commence field studies in Europe on selected biocontrol targets • Submit willows as candidates for biological control to Australian Weeds Committee/SCARM • Declare willows as biological control candidates under the Biological Control Act 1984
5. Anticipated Products • Symposium Proceedings for current knowledge on willow management
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• Guidelines for best-bet management of willows and stable revegetation practices • Protocols for rear and release of willows biocontrol agents • Approved release of first willows biocontrol agent in Australia • Communications plan for willows to support National Strategic Plan
6. Anticipated Outcomes • Establishment of stable revegetation practices at best-bet demonstration sites • Measurable improvements to IWM of willows and eradication of populations in significant localities • Attempted establishment of at least one biocontrol agent for willows in Australia • Ongoing liaison with stakeholders and land /water managers in relevant States through National Taskforce about biocontrol of willows biocontrol agent in Australia
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Management of willows remains a serious threat to riverine ecosystems in the MDB. Despite recent work towards a National Strategic Plan for willows and access to the National Weeds Program for funding some 1 year projects, there is no co-ordinated research effort in Australia. Planning is under way for small projects to be funded under NWP and in the new CRC for Australian Weed Management, but the scale of the problems and knowledge gaps requires willows R&D to be raised to a new threshold.
8. Opportunities for linkage or collaboration Opportunities exist for MDBC to cement links to Universities, CRCs, management organisations and water distributors, landholder and community groups. Much can be achieved in the next 5 years by working with the States and Federal Government to achieve actions described in the NSP for willows.
9. Opportunities for end-user involvement The involvement of land managers in the development of material on best management practices and publicising its effectiveness is an integral part of this project. End-users involve key government bodies, land and water management authorities, experts, interest and user groups. They will be involved in all aspects of the project where direct liaison will be undertaken to determine the range of approaches to dealing with the problem. Land managers and community groups will be utilised in the re-distribution of biological control agents from established sites where appropriate.
10. Mechanisms for transfer and adoption • Publication and possibly Web-based information on control and other advisory material, targeting landholders and management agencies. • Field days and workshops targeting landholders and community groups • Report evaluating scientific knowledge, targeting agencies and funding agencies • Published paper or equivalent, targeting scientific community.
11. Estimated cost and duration Medium Term = 5 years Cost = $225 000/year
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(nb: Research into biocontrol is anticipated to take up to 9 years to achieve all aspects of research and implementation)
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7.4.9 Research Project Brief 9: Lippia as a Problem Species in the Riparian Zone and on Floodplains
1. Key management Issues(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issues or policies The introduced plant, lippia Phyla canescens, occurs on major floodplains in the Basin, including some Ramsar sites. Lippia has certain characteristics commonly associated with problem plant species; wide environmental tolerances (dry, shallow wet and brackish conditions), multiple ways of regeneration (seed, fragments, tap root), and is an aggressive competitor (its prostrate habit favours resource capture and leads to extensive mono-specific swards). Negative effects attributed to lippia are both economic and environmental, and include: soil degradation, through bank slumping and tunnel erosion, particularly on certain soil types (cracking clays or vertisols), resulting in downstream slugs of sediment; invasion of native grasslands and woodland understorey, resulting in loss of productivity for cattle enterprises and loss of plant biodiversity.
Lippia is not included in national listings of problem plant species such as WONS (Weeds of National Significance: a list of the 20 most significant weeds from habitats across Australia). However, within the MDB, it is recognised as a current and expanding problem in riparian and floodplain habitats in the Basin, particularly in northern floodplains2. Environmental factors thought to favour lippia are reduced flooding frequency (with implications for river regulation) and set-stocking. Interactions between these may influence rate of spread and outcome of competition with other species.
Lippia can be managed with a very limited range of herbicides (Lucy et al. 1995), or by land cultivation. Efforts by individual landholders shows that containment is feasible, but as yet such approaches are individual and have not been widely adopted. The negative effects of lippia are expenses associated with controls and with shifting from a set stocking rate, decline in farm productivity, soil erosion and loss of biodiversity. None of these have been quantified. Lack of documentation makes it difficult to assess lippia as an economic and environmental weed in its own right and relative to other weeds. Very little has been published on lippia growth and ecology, either in Australia or elsewhere, although it is accepted that certain water regimes and shade can limit growth.
An indicator of this poor state of knowledge about lippia ecology and its economic impact is that the only relevant publication to date (Lucy et al. 1995) is reliant on unpublished reports and personal communications, yet this remains the single authoritative source on lippia in Australia. It has been reprinted twice to meet popular demand. Its leading author considers an update, incorporating best management practices and more current understanding is merited (Lucy, pers. comm. 2001).
2 Questionnaire completed as part of stakeholder consultation: see Main Report. A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 149 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
3. Project Objectives • To make available and publicise control measures that are sustainable and commercially viable • To document the geographic variation in the ‘weediness’ of lippia across the Basin, and relate these to environmental factors determining lippia growth • To quantify the extent and severity of lippia invasion, in terms of geographic extent and economic costs. • To update and review the state of scientific and technical information on lippia. • To provide a co-ordinated response to lippia across the MDB Suggested information targets to work towards are: obtaining sufficient information to make a formal risk assessment of lippia, using national protocols; intra-regional focus for economic and environmental impact assessment, with a sound basis for extending knowledge wider.
4. Key Tasks • Prepare and publish an updated version of the QDPI Agdex 640 / 240 “Lippia Review” by Lucy et al. (1995) - or equivalent - incorporating best management practices and practical control measures, environmental issues, economic costs as determined through this project, plus other information determined through international literature and studies done during the course of this project3 . • Develop, publicise and disseminate Best Practices approach for control of lippia, based on case histories and examples, and working through and with Landcare groups, and also through consulting with relevant state and federal agencies involved in land management policy and regulation. • Assess and outline prospects, opportunities and limitations for control of lippia explaining how these vary across the Basin, in relation to land use, soil types, landscape, rainfall patterns. • Identify the information gaps impeding recognition of lippia as a significant weed, using the WONS criteria as a template, and outline the case, if any, for further studies on lippia (life history, ecology, physiology, genotypes). This is to be in the form of a short scientific report (10-20 pp, referenced) primarily to the MDB Commission, but relevant also to government departments, industry groups, and research organisations. • Document short-term and long-term effects of lippia on productivity of floodplain enterprises, based directly on farm case histories, and by working through Landcare groups. These case histories are to be set within the broader context of the range of farming enterprises, soil types, management styles in relation to stock, and land use. • Document a range of situations and circumstances where lippia is an environmental weed by locating and documenting a suite of paired examples (invaded and non-invaded patches of native vegetation), covering as far as possible different land systems and different bioregions, and including recent land use and flood history.
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• Investigate the interaction between grazing, water regime and lippia expansion by: either, a fully replicated experiment to determine strength of competitive interaction between lippia and key floodplain grasses, using grazing or water regime as co-variates.4
5. Anticipated Products • An updated version of Lippia Review • Advisory / extension material on lippia control
6. Anticipated Outcomes • Increased public knowledge of severity and extent of lippia as a weed • Tools for graziers to manage lippia made up to date and more widely available • Improved understanding of factors contributing to lippia invasion • Directions needed for lippia management in the future, based on information obtained through this project (assessment of control options for lippia, economic estimates, environmental situations) • Capacity to make a formal assessment of lippia as a weed using nationally accepted criteria.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Lippia is a Basin-specific and an issue for the Riverine Environment Sub-Program because: • First, because it is a pest species at a regional rather than national level, investigations into lippia control are unlikely to attract support from national bodies such as National Weeds Strategy and the CRC Weed Management Systems. Lippia will continue to be considered as only a regional issue until its extent and impact, both economic and environmental, are better documented and its potential properly recognised. • Second, the negative effects on soil and biodiversity attributed to lippia can directly compromise other objectives and priorities within the Riverine Environment Sub-Program. For example: tunnelling and bank slumping on vertisols change, indefinitely, discharge-inundation relationships and so will compromise both estimates and delivery of environmental water allocations to floodplain wetlands (RESP 3); the displacement of native grasses and broadleaf species, either directly by lippia or as a consequence of tillage intended to control lippia, counters the Nature Conservation objective (RESP 4).
8. Opportunities for collaboration Opportunities for collaboration exist in relation to Landcare groups, shires, and universities through research officers or students (economic assessments, analysis of environmental data). Potential
4 An alternative opportunity may be available but the feasibility of doing this would need to be established carefully. A set of exclosures was established on the Gwydir floodplain by UNE (John Duggin, Rob McCosker) for a LWRRDC-funded project in mid-1990s, and monitored for a few years. These data were intended to investigate interactions between stock and wet-dry cycles for different parts of floodplain. The data have not been published, and it may be cost-effective to invest in their analysis and writing-up, rather than invest in a new investigation. However, progress and plans for publication, data ownership and availability would need to be clarified. Initial enquiries through LWA (formerly LWRRDC) have been positively received. A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 151 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
collaborators are regional agency offices with responsibilities for land use and primary production, or for conservation and the natural environment.
Connection and input from national or state research organisations interested in environmental weeds, and sustainability of grazing enterprises would be valuable. Representatives of state (eg Qld DPI, NSW NPWS) or federal organisations (eg CRC Weeds Management Systems or CSIRO Sustainable Ecosystems) could be invited to participate on the Steering Committee.
9. Opportunities for end-user involvement The involvement of landholders in the economic analysis and in the development of material on best management practices and publicising the same is an integral part of this project. Similarly, there are opportunities for local government involvement in defining lippia extent.
The involvement of conservation groups and agencies in locating sites and in establishing a scientific basis for the land use and environmental factors that facilitate the expansion of lippia is also an essential part of this project.
10. Mechanisms for transfer and adoption • Publication and possibly Web-based information on control and other advisory material, targeting landholders and management agencies • Field days and on-farm demonstration, specifically targeting landholders but open to others • Report evaluating scientific knowledge, targeting agencies and funding agencies • Scientific paper or equivalent, targeting scientific community. • Steering committee with representatives from different arenas (research, land holders, land management and policy).
11. Estimated Costs and Duration Medium Term = 3 years Cost = $150 000 - 200 000 (nb: requires a team of mixed expertise).
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7.4.10 Research Project Brief 10: Integrated Control of Blackberry
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies Blackberry (Rubus fruticosus aggregate) was introduced from Europe in the 1840s and was recognised as an important weed by the 1880s. Because of its invasiveness in a range of temperate environments both in agricultural and natural ecosystems, it is now one of the most important weeds in southern Australia and was declared a Weed of National Significance in October 2000. In primary production Blackberry is a major weed of pastures and plantation forestry, while in natural ecosystems it is able to invade native forests, riparian zones and areas of conservation value.
Blackberry is an important weed because of its vigorous growth and prickly nature which makes it objectionable to most grazing animals. Because of effective seed distribution by fruit-eating birds and mammals and its vegetative propagation from cane tips, Blackberry can cover large areas in short periods. Its dense canopy excludes light from the soil surface, effectively competing with and dominating other vegetation. In plantation forestry it can affect the establishment and growth rate of both softwood and hardwood seedlings while it can prevent regeneration of natural hardwood forests.
The impenetrable, prickly brambles provide harbour for vermin such as rabbits and foxes. Because of its biennial growth habit, the majority of biomass in a bramble is dead material from previous years. Because of this, large infestations are a considerable fire hazard. When growing along water courses, it restricts access to watering points by farm animals and to people for fishing. The streambank environment is subject to considerable erosion pressures by water, stock access and people. In this environment Blackberry is increasingly being recognised as a short term stabiliser, but a long term destabiliser, of riparian areas. In the early stages of invasion Blackberry will grow over, or occupy gaps in native vegetation and actually assist soil stability. Invasion will be faster in disturbed areas. However, where the invasion has progressed to dominate or displace native vegetation, increased erosion has been observed.
Based on information supplied by all the States, Field & Bruzzese (1984) estimated that the cost of Blackberry to Australia was $42 million per annum.
The European Blackberry aggregate has probably reached the climatic limits (rainfall and temperature) of its potential range in Australia, however, individual species of the aggregate have not reached their potential range within the climatic range. Some species such as R. procerus are very widespread whereas others are still very restricted in distribution. Although there may be minor differences in climatic and soil requirements between the species, each species has the potential to spread to the full climatic range in Australia.
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The potential for continued spread by each species is enhanced by their vigour, their high reproductive capacity from both seeds and production of daughter plants, their adaptability to a wide range of environments and soil types and the very effective seed dispersal by fruit eating birds and mammals. The effect of biological control will also impact on the spread of some Blackberry species. Species which are very susceptible to the rust will decrease in distribution while species which are resistant will continue to spread.
3. Project Objectives • To conduct workshops to assess what best management practices are currently being utilised by land managers in riparian habitats for control of Blackberries within the MDB. • To evaluate uses of existing unregistered herbicides for blackberry control, in co-operation with herbicide companies • To re-evaluate management techniques in light of recent research and produce blackberry "best bet" control information package for managers of riparian habitats within the MDB. • To investigate and begin introduction of additional biological control agents in co-operation with the CRC for Weed Management Systems and the Weeds of National Significance program.
4. Key Tasks • Identify key land managers impacted by blackberry in riparian regions within the MDB and organise workshops to discuss "best bet" management options. • Review herbicide options for blackberry and in collaboration with herbicide companies. Begin evaluation and registration of herbicides where appropriate. • Produce blackberry "best bet" control information package including where and when chemical control, mechanical control, rehabilitation and biological control should be used. • Investigate new biological control agents to: (a) attack all blackberry species and (b) attack blackberry under the canopy of other plants. With collaborative research and combined funding with CRC for Weed Management Systems, Weeds of National Significance and State Departments investigate: - Climatic factors affecting effective rust establishment and consequent collection of rust biotypes from Europe to attack all blackberry species in a wide range of habitats in Australia. - Introduction of a host specific sawfly that tunnels inside blackberry canes causing the brambles to collapse. - Introduction of host specific mite to defoliate and stunt brambles.
5. Anticipated Products • Blackberry "best bet" control information package • New herbicide(s) registered for blackberry control in riparian habitats. • Introduction and release of new biological control agents to attack all blackberry species and to control blackberry in a wide range of environmental conditions.
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6. Anticipated Outcomes • Land managers more informed and using better and more sustainable techniques to control blackberry within the MDB. • The MDBC in collaboration with the CRC for Weed Management Systems, the Weeds of National Significance program and State Governments, oversee the introduction and release of a suite of new biological control agents leading to the long term reduction of blackberry in the MDB.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) • The MDBC has the opportunity to become part of an extensive blackberry control program that could deliver significant savings and benefits for the MDBC. By becoming a collaborative partner with the CRC for Weed Management Systems and the Weeds of National Significance program, the blackberry program will become more comprehensive, happen faster and have a more specific focus on MDB.
8. Opportunities for linkage or collaboration • CRC for Weed Management Systems • Weeds of National Significance • Government Departments • CSIRO Entomology
9. Opportunities for end-user involvement The involvement of land managers in the development of material on best management practices and publicising its effectiveness is an integral part of this project. End-users involve key government bodies, land and water management authorities, experts, interest and user groups. They will be involved in all aspects of the project where direct liaison will be undertaken to determine the range of approaches to dealing with the problem. Land managers and community groups will be utilised in the re-distribution of biological control agents from established sites where appropriate.
10. Mechanisms for transfer and adoption • Publication and possibly Web-based information on control and other advisory material, targeting landholders and management agencies. • Field days, targeting landholders • Report evaluating scientific knowledge, targeting agencies and funding agencies • Published paper or equivalent, targeting scientific community.
11. Estimated cost and duration Part A - Best Practice Management Short Term = 1 year Cost =$90 000
Part B - Biological Control Development Long Term = 5 years Cost = $120 000/year for 5 years
(nb: this could be reduced depending on outcomes of Weeds of National Significance Applications).
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7.4.11 Research Project Brief 11: Integrated Management of Alligator weed
1. Key Management Issue(s) (as identified in the RESP) • R1a) Improving planning to support sustainable use of floodplains, wetlands and rivers • R4a) Re-establishing populations and communities • R4b) Managing floodplain, wetland and riparian habitats • R4d) Managing threats to communities and habitats • R0a) Transfer and adoption
2. Context, and how this addresses key management issue(s), strategies or policies Alligator weed (Alternanthera philoxeroides) is one of the greatest threats to our rivers, wetlands and irrigation systems in Australia. It has declared noxious in all Australian states and territories and a prohibited plant in Victoria and Tasmania. The present distribution of alligator weed in Australia is cause for considerable concern and it is one of the 20 Weeds of National Significance.
Alligator weed disrupts the aquatic environments by blanketing the surface of the water impeding penetration of light, gaseous exchange with adverse effect on flora and fauna. Mats impede flow and lodge against structures thereby promoting sedimentation and contributing to flooding. They prevent access to and use of water, providing habitats for mosquitoes and degrade natural aesthetics. The range of impacts that alligator weed can have effects the community in a number of ways. The effects on agricultural communities include; increased costs, decreased production, an additional difficult problem to deal with and potentially the loss of industries (i.e. turf).
More than 800 alligator weed infestations (in backyards) were located in Victoria including 15 naturalised sites. A few backyard infestations were found in Wodonga, Shepparton, and Kyabram recently. An isolated patch also occurs at Woomargama near Albury in southern New South Wales. A large infestation of alligator weed was located on Barren Box Swamp and connected irrigation channels near Griffith in the Murrumbidgee Irrigation Area in 1994. Over $3 million dollars have been spent so far attempting to eradicate this infestation.
The Department of Natural Resources & Environment, Victoria has been conducting an alligator weed management program since 1995. The results of the program are promising and encouraging, thus some good information is available on this species and its management in Victoria.
Alligator weed currently only occupies a small area of its potential range in Australia. Thus there is great potential for it to spread and occupy extensive areas within MDB region. Its spread occurs by anthropotenic activities and natural movement in waterways. Early detection is needed for eradication of new infestation to be possible and a dramatic reduction in rate of spread will only be achieved with community involvement and a coordinated approach. The primary aim of this project is to prevent invasion of this aggressive alien species into the MDB.
3. Project Objectives • To identify and record the extent of alligator weed infestations
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• To identify high risk sites • To identify vectors and reduce dispersal • To put in place management plans for alligator weed in Murray Darling aquatic ecosystems • To eradicate/control all known infestations • To raise the awareness of landholders and key water users within the MDB and the broader community on the threat that weeds present to aquatic environments and develop an information program that explains what they can do to prevent new infestations from developing.
4. Key Tasks • Conduct systematic survey of alligator weed in Murray Darling aquatic ecosystems to accurately determine its current distribution • Document its spread over time to understand its patterns and rate of growth. • Liaise with key experts, managers, and interest groups etc to assist in documenting current distribution. • Identify priority sites for control based on the level of infestation and damage etc. • Develop management plans for all alligator weed infestations according to priority sites and implement these plans. • Develop a coordinated response for management of alligator weed across the MDB and establish a group with appropriate representatives. • Develop and implement a public awareness/education program, which may involve the distribution of printed information on alligator weed, direct contacts with key groups, information days, field days etc. • Monitoring of all high-risk infestations annually over 3 years.
5. Anticipated Products • A standard response plan to deal with new infestations of alligator weed • Extension materials for public awareness and education purpose
6. Anticipated outcomes • An improved understanding within key government bodies, land and water management authorities, experts, interest and user groups as to the methods of dealing with potential and new infestations of alligator weed • Improved understanding of the social, economic and biodiversity impacts of alligator weed • Better treatment packages for management of alligator weed in MDB • Reduce rate of spreading alligator weed • A coordinated response plan to dealing with new and possible infestations of alligator weed within the MDB and basin-wide.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. This is particularly important because pest species have potential economic, social and ecological impacts.
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8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, land and water management authorities, experts, and interest and user groups. International linkages are also important to draw on the knowledge gained about particular pest species elsewhere.
9. Opportunities for end-user involvement End-users involve key government bodies, land and water management authorities, experts, and interest and user groups. They will be involved in all aspects of the project where direct liaison will be undertaken to determine the current distribution of alligator weed, priority sites for control, and to develop management plans.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to appropriate methods of disseminating results of the project with the community • The steering committee will include appropriate representatives from end-users. • The range of information concerning the project will be disseminated to end-users which will include extension material for land managers, landholders and interest groups.
11. Estimated cost and duration Medium Term = 3 years Cost = $300 000
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7.4.12 Research Project Brief 12: Research and Management of Gambusia
1. Key Management Issue(s) (as identified in the RESP) • R1a) Informing planning to support sustainable use of floodplains • R4a) Re-establishing populations and communities • R4b) Managing floodplain, wetland and riparian habitats • R4c) Managing instream and estuarine habitats • R4d) Managing threats to communities and habitats • R0a) Transfer and adoption • M2a) Capacity building and engagement • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies This project represents a coordinated approach to control gambusia within the MDB. It combines six closely related projects which may potentially be funded separately but together provide for a comprehensive program to address necessary research and management of gambusia. PART A - Gambusia Task Force PART B - An Educational Strategy for Gambusia PART C - A Coordinated approach to the Control of Gambusia PART D - Determination of the Distribution of Gambusia PART E - Targeted Research on the Biology and Ecology of Gambusia PART F - Investigation of Potential Biological Control Technologies for Gambusia Synopsis Gambusia, a species native to the USA and Mexico, was first introduced into Australia to Sydney in 1925 to control mosquitoes. Gambusia have spread across much of the country, both by deliberate introductions and through their own ability. They now occur in both inland and coastal drainages in New South Wales, South Australia, Victoria and coastal drainages of Queensland. Gambusia are present in parts of Western Australia, although they are not currently known to occur in the Northern Territory and Tasmania. Gambusia are widespread and common throughout the MDB and occurs in almost every conceivable aquatic habitat in the basin except for tableland streams where winter temperatures are thought to be unfavourably low. It is the most abundant and ubiquitous small introduced fish species in the MDB.
Gambusia have wide environmental tolerances and inhabits a wide range of habitats. They have a generalist nature and has the potential for rapid increases in numbers due to being a livebearer, having an omnivorous diet and aggressive nature. Many of these characteristics make gambusia likely to impact on a range of native fish, amphibian and invertebrate species. Impacts may include competition for resources such as food and space, and predation of eggs, larvae and juveniles of native fish, amphibian and invertebrate species.
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PART 12A Gambusia Task Force The establishment of the National Carp Task Force in 1996 as a result of public interest and pressure has promoted a more coordinated approach and national focus on carp control in Australia. The Task Force has membership from Commonwealth, State and Territory agencies with an interest in carp, researchers, recreational and commercial fishers and local government. It has enabled consolidation and focus of community energy in relation to management of this pest species in Australia, and has been able to gain political support to influence decision-making. The aim of the Task Force is to eradicate carp from all Australian aquatic habitats through a strategic action plan that promotes coordinated research, provides good information, explores commercial opportunities and seeks complementary legislation (Koehn et al. 2000). It highlights the need to focus on a natural resource management strategy using pest management principles. The Task Force has developed an action plan which includes research, information, commercial exploitation and legislation objectives. Information is disseminated to the public and interest groups via a web page, regular newsletters, a database for carp records as well as widely available posters and brochures. These have helped to highlight the issue of carp within the broad community. The concept of a generic Task Force has potential to be applicable to numerous other pest species.
Given that gambusia represents another introduced species which is widespread and common across the majority of the MDB, the value of establishing a Gambusia Task Force is clear. It would enable better coordination of gambusia management and research in the MDB, improve information dissemination and increase the awareness of the issue of gambusia.
3A. Project Objectives • To establish a Gambusia Task Force to enable a coordinated approach and community focus to control and manage gambusia within the MDB.
4A. Key Tasks • Use the National Carp Task Force as a model for the development of a Gambusia Task Force to enable a coordinated approach and community focus to control gambusia within the MDB. • Review the National Carp Task Force to determine the levels of success in achieving a range of activities by the group. • Establish the key roles of the Gambusia Task Force including the setting of priorities and recommendations for management, developing action plans, which include research, information and legislative objectives. Activities which the Gambusia Task Force could undertake could include forums to provide information and feedback to the community. • Establish a protocol to identify appropriate participants to be involved in the Gambusia Task Force. They should include appropriate representatives from the community, stakeholders, science and government. • Ensure that representatives from the Gambusia Task Force are included on steering committees for all related gambusia projects which occur within the MDB. • Develop a framework for information dissemination. This should identify a range of appropriate techniques for the identified range of target audiences. It should provide regular updates on
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activities, research and management within each state and in a basin-wide context, their findings, successes and failures, future directions etc. This may include the establishment of a website through the MDBC website.
5A. Anticipated Products • The establishment of a Gambusia Task Force within the MDB. • A coordinated information package easily accessible to the general public and interest groups concerning the Gambusia Task Force, their roles, achievements etc. • Setting of priorities and recommendations for management and action plans.
6A. Anticipated Outcomes • A coordinated approach and increased community focus to control and manage gambusia within the MDB. • Improved liaison between those involved in control and management of gambusia. • An improved understanding of the general public concerning the management of gambusia and their role in the management and control of gambusia.
7A. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8A. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, local government, scientists and other experts involved in the research and management of gambusia, and in particular the strong involvement of interest and community groups and the general public.
9A. Opportunities for end-user involvement End-users involve key government bodies and local government across the MDB, land and water management authorities, scientists and other experts involved in the research and management of gambusia, interest groups etc.
10A. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating the results of the project within the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users in a range of formats which should provide regular updates on activities, research and management within each state and in a basin-wide context, their findings, successes and failures, future directions etc. This may include the establishment of a website through the MDBC website.
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11A. Estimated cost and duration Establishment Short Term = 1 year Cost =$120,000 nb: The establishment of a Gambusia Task Force will not achieve its objectives unless it is seen as an ongoing commitment, which will require ongoing operating funds.
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PART 12B An Educational Strategy for Gambusia The need for an educational program has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). They noted that people have some degree of understanding of ecological and economic effects of some pest species, but few recognise the connection between their own activities and the accelerating rate of invasions. Public education campaigns should be focused on ensuring that no further introductions of gambusia occur. Where eradication or reduction programs are undertaken, an educational component should be included to improve the public’s understanding of the issue of gambusia, and to minimise the potential of any human dispersal. Particular priority for educational campaigns should be given to areas where gambusia are known not to occur. There is great potential to educate the public concerning issues such as gambusia. An educational campaign should be separated into different components for different target audiences with particular reference to: • Potential methods of dispersal/transportation of gambusia by human agents (e.g. aquarium trade, mosquito control) • The importance of the public’s role in the introduction and spread of gambusia (e.g. deliberate or accidental translocations) • Ecological, social and economic impacts of gambusia (e.g. predation and competition with native species, cost of control) • Options available for control and eradication programs. • The observed connection between environmental degradation, disturbance and invasion success i.e. in degraded/disturbed habitats the invading species may often be a symptom rather than a cause of the problem. Addressing factors that cause degradation (e.g. altered flow regimes, etc.) are important in the overall education and management of gambusia.
All educational material must be accessible in a variety of forms to reach all identified target groups e.g. brochures, booklets, posters, activity and resource kits for schools, media stories (e.g. current affairs, ABC Landline, newspaper and radio articles). The material also needs to have a MDB context that can provide comprehensive information at a basin level as well as more specific state-oriented and local information. This information could include a gambusia resource guide on the internet and possible as hard copy as a reference tool for gambusia within the MDB. The project will review existing information concerning gambusia in the MDB and build on successful available educational material (e.g. Queensland DPI, Victoria DNRE).
Improving the public’s understanding of gambusia and increasing their awareness of gambusia can have added benefits e.g. the public can provide information on the location of gambusia for which our knowledge is limited. An understanding of the current distribution of gambusia could assist in targeted management actions including monitoring and control. The program may be implemented along the lines of successful state-orientated programs such as Waterwatch and be coordinated throughout the MDB as a ‘Pestwatch’ Program and included as a component of current projects undertaken within the MDB. There is also great potential for involvement of the public in actively participating in the control of gambusia through modification of community attitudes and activities. The most important component in
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modifying attitudes involves educating the public on the impacts of gambusia on the natural environment and the direct and indirect effects on their own lifestyles.
3B.Project Objectives • To increase the awareness of the general public, key stakeholder and interest groups, landholders, catchment management authorities, school students etc of the issue of gambusia in riverine environments within the MDB. This includes factors that enhance their success, their detrimental impacts and what pre-emptive management and control methods can be undertaken. • To minimise any potential role the public and stakeholders may have in the introduction and/or spread of gambusia (e.g. to modify public behaviour). • To enable the community to provide information on the location of gambusia which can assist in the management and control of this species.
4B. Key Tasks • Review existing educational information concerning gambusia within the MDB. • Determine the range of management authorities, interest and community groups which an educational program needs to target. • Identify potential barriers in educating particular groups (e.g. due to social and/or cultural views where gambusia are not recognised as ‘pests’ or detrimental) and develop appropriate methods to address these issues and effectively disseminate information. • Identify key misunderstandings and knowledge gaps concerning gambusia including their introduction, spread, impacts and available methods of control. • Determine what information needs to be disseminated to the range of target groups. • Develop material for the general public, school students and other interest and stakeholder groups to improve their understanding of gambusia within the MDB. This includes issues relating to introduction and spread, impacts on the aquatic environment in association with other degrading processes, and the public’s role in minimising the introduction and/or spread of gambusia. The material would include a component to ensure that the public is able to correctly identify gambusia or have contacts for expert identification, and highlight cases where gambusia could be confused with native species. • Develop programs aimed at fostering a sense of ownership and encourage active involvement of these groups in preventing introductions and spread, and to reduce the impacts of gambusia (e.g. knowledge generation, behaviour modification, habitat rehabilitation). • Facilitate the public providing information on the location of gambusia as part of a coordinated program. An improved understanding of the distribution of gambusia will potentially assist in determining and implementing appropriate management and control programs and restricting further spread.
5B. Anticipated Products • A coordinated educational program for gambusia within the MDB
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• Targeted information packages designed for a range of groups - brochures, booklets, posters, study packs, website information, database of resources and contacts, talks, displays, stickers, signs, cd roms • A coordinated media campaign – television, newspaper and radio advertisements
6B. Anticipated Outcomes • Improved understanding within the general public of how and why gambusia are identified as ‘pests’ by government departments. • Increased public awareness of gambusia within the MDB, including factors that lead to their success and spread, their impact on the environment and the role the public can play in minimising their introduction and spread. • Increased public involvement and ownership of the issue of gambusia. • Improved coordination of gambusia information across relevant government agencies within the MDB, as part of an integrated management approach to gambusia. • Improved appreciation within government agencies and the general public of the value and importance of continuing education concerning gambusia. • Increased awareness of the importance of including gambusia as an integral part of MDB projects e.g. river rehabilitation.
7B. The Commission’s need to fund this work (how will it meet our Strategic Objectives) The need for an educational program has been highlighted by the MDBC Riverine Issues Working Group (MDBC & CRCFE 1999). Managing the threats of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8B. Opportunities for linkage or collaboration This project has a strong potential for extensive linkages and collaboration between numerous groups. These include key federal government groups, state natural resource agencies, river management committees, catchment management authorities, councils, experts in invasive species, fishing groups, aquatic recreational groups, state education departments, conservation groups, research groups, universities, social researchers, aquaculture groups, aquarium trade and general interest groups etc.
9B. Opportunities for end-user involvement Those groups identified above represent the wide range of end-users who will benefit from a comprehensive educational program concerning gambusia within the MDB. Their involvement will be sought in a variety of ways, particularly in relation to what information needs to be disseminated, key misunderstandings and knowledge gaps concerning gambusia and their management, potential barriers to education, methods of fostering ownership, participation in preventing introductions and spread of gambusia and providing distributional information.
10B. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess the most appropriate methods for disseminating education packages to various groups within the community
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• Steering committee would include appropriate representatives in order to determine priority education areas and the most effective approach in disseminating education packages to the wider community • Dissemination of a wide variety of information to wide range of end users. Dissemination of information as a comprehensive educational program is the key aim and output of this project.
11B. Estimated cost and duration Short Term = 1.5 years Cost =$150 000 (nb: This cost may increase depending on the costs associated in providing particular material).
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PART 12 C A Coordinated approach to the Control of Gambusia This sub-project incorporates several components into a coordinated approach to the control of gambusia within the MDB: a) an accessible information package for managers responsible for gambusia control b) the establishment of a standard set of procedures to assess the effectiveness of control programs and d) the development of a database to incorporate this information.
All components are closely linked and are all important in the development of a coordinated gambusia control program.
a) An accessible information package for managers responsible for gambusia control A range of public authorities are responsible for the management of waterways within the MDB and across Australia. The control and management of gambusia is one issue these authorities may tackle, although there is very limited information available about appropriate control techniques. There have been very few documented control programs specifically targeted at gambusia recorded to date, due mainly to the absence of control methods which are both effective and specific for gambusia. Current suggested options include the use of predatory fish species, poisons such as rotenone and lime, physical control (e.g. electrofishing, netting, trapping), environmental rehabilitation or manipulation. Control and management programs often tend to be a highly variable in their approach, methodology and success. The lack of a consistent set of guidelines for best management practice and availability of relevant information means that many control programs may not be undertaken effectively and efficiently, using appropriate reasoning and the most up-to-date information.
There is a clear need to develop an information package for managers concerning the range of possible techniques available for the control of gambusia. Such an information package should include a review of each control technique including details of the costs and benefits of each technique, their applicability and practicality for a range of areas and conditions, relevant controls and legislation relating to techniques, and standard methodology. Such a package should also provide an important guide to available knowledge and references including control programs which have already been undertaken and their results, as well as contact details for relevant government bodies and individuals experienced in control of gambusia. Such an information package would facilitate a far more coordinated approach to management and control of gambusia within the MDB which would be more effective and efficient and allow for transfer of information and technology between appropriate people. This information would provide an effective decision-support tool, providing indications of where and how particular methodologies should be applied. Improved liaison and information transfer would enable better planning of control programs, building on the existing experience of managers. It may also generate interest and commitment from stakeholders.
b) The establishment of a standard set of procedures to assess the effectiveness of these control programs There would be a clear benefit in having a more coordinated approach to control programs for gambusia within the MDB. The development of a standard protocol for managers to follow when undertaking A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 167 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
gambusia control programs would enable their effectiveness to be assessed in a more quantified way than is currently occurring.
A standard protocol could include specific targets which should be aimed for (e.g. eradication of a gambusia, improvement in environmental conditions such as increased native species diversity and abundance) which will assist managers in clarifying their aims. The results of gambusia control programs, whether entirely or partly successful or unsuccessful, are an important source of information in the development of more efficient programs.
c) The development of a database to incorporate this information. This project includes the development of a database to incorporate the above information concerning field control programs and monitoring their success. Those involved in control programs could fill out a standard data sheet (Part b) which could include information such as methodology, specific site conditions and results of the programs which could be incorporated into the database. Thus anyone contemplating undertaking a control program could base their decisions on the available guide to control programs (Part a) and the results of control programs already undertaken (Part b). For example, a local council may be contemplating controlling gambusia in a particular habitat. By reviewing the database, they would become familiar with all their options, appropriate procedures to follow and possible likelihood of success. They would be able to contact all relevant people to obtain further advice.
The establishment of a database via the MDBC website would maximise the accessibility of this information. A procedure would need to be set in place concerning how information is entered and maintained on the database. Many managers may not have the time or inclination to review numerous scientific papers and so the provision of information in a suitable format which is easily accessible is important. The use of a standardised protocol will increase the awareness of a range of managers to include a consistent form of evaluation of control programs, which will depend on particular situations.
The overall project would develop a wide range of information relating to gambusia control programs in a variety of formats. These would include the MDBC website with specific information packages about control techniques (e.g. fact sheets), downloadable forms to fill in to document and evaluate control programs, a database to scrutinise for information as well as incorporate information, informal chatrooms for advice, contacts and links to experts and key government bodies, researchers etc, directions on where to obtain more information such as scientific reports and articles etc. Such a system will also potentially make the control of gambusia in areas recently introduced easier to deal with.
3C.Project Objectives • To develop an easily accessible information package for managers, as well as other interest and user groups responsible for gambusia control within the MDB. • To establish a standard set of reporting procedures for managers to assess the effectiveness of control programs in order to facilitate a coordinated approach to control and management programs for gambusia within the MDB. • To develop a database to store information on control and management programs for gambusia within the MDB.
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• To improve communication between gambusia management projects within the MDB.
4C. Key Tasks a) - Information Packages • Review existing and potential methods of controlling gambusia within Australia and overseas. • Contact key experts, managers, interest and user groups within Australia and overseas to obtain their advice concerning current and potential control methods. • Collate this information into an easily accessible information package for managers responsible for undertaking gambusia control programs within the MDB. • Identify the end-user needs as well as resources available to all relevant managers and others responsible for carrying out gambusia control programs. • Determine the most appropriate methods to disseminate this information, which may primarily involve the development of a web-based information source. • Develop this information package. It should include all relevant information on control techniques (i.e. costs and benefits of each technique, their applicability and practicality for a range of areas and conditions, relevant controls and State and Federal legislation relating to techniques, standard methodology, sources of additional information including scientific and management literature, key contacts for advice and requirements for approval etc.). This information package should ensure that those considering gambusia control programs can make informed decisions using all essential and relevant information and are able to integrate approaches to obtain maximum benefits. • Promote and publicise this information package to all relevant end-users. • Identify key government agencies and other relevant organisation who should participate in maintaining and contributing to this information package. A formal process should be put in place to ensure the package is kept up-to-date. • Ensure the information resource incorporates a feedback component to determine whether it is effective and achieves its goals. The resource should be monitored and assessed on an annual basis.
b) - Standard Procedures for Gambusia Control Programs • Review current gambusia control programs which occur within Australia and most specifically within the MDB. • Determine how a more coordinated approach could be developed for managers to follow when undertaking gambusia control programs to enable a quantified assessment of them. • Determine how this approach could include control and monitoring by community, interest and users. • Contact key experts, managers and interest groups involved in gambusia control programs to obtain their advice about how control programs could be monitored in a coordinated way. This should include identification of the needs and expectations of these groups, their commitments to monitoring control programs and how this process can be promoted and monitored. • Develop a series of standard protocols for monitoring the effectiveness of gambusia control programs. • Determine a methodology to collate this information (as referred to in Part c) to enable a coordinated approach to assessing the effectiveness of control programs with the aim of developing more efficient programs.
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• Determine the most effective method of disseminating these standard protocols to end-users. • Promote and publicise these standard protocols to all relevant end-users. • Identify key government agencies and other relevant organisation who should participate in collating this information.
c) - Database • Develop a database to incorporate information obtained from Part a and Part b. • Determine how this database should be maintained and kept up-to-date. • Promote and publicise the existence of the database which should include an explanation of how information can be added to it, and how it can be used by relevant managers, interest groups etc. • Review the effectiveness of the database, as well as the information provided from Part a and Part b, possibly on an annual basis.
5C. Anticipated Products • A comprehensive information package for those involved in undertaking gambusia control programs within the MDB. • Standard set of procedures for those involved in undertaking gambusia control programs to enable quantitative monitoring of these programs to assess their effectiveness. • A database to document information on appropriate methods of controlling gambusia and their effectiveness. • A publicity campaign to inform stakeholders of the information package, procedures, database and website.
6C. Anticipated Outcomes • A coordinated approach to undertaking gambusia control programs within the MDB. • Improved linkages and information transfer between all groups involved in gambusia control programs within the MDB. • A consistent approach to monitoring the effectiveness of gambusia control programs within the MDB. • An improved recognition by all relevant user groups that gambusia control programs need to be monitored and reviewed to assess their effectiveness. • Better decision-making for all groups involved in controlling gambusia within the MDB. • More efficient and effective control programs for gambusia within the MDB.
7C. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8C. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientific experts, mangers, interest and user groups involved in the control and
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monitoring of gambusia. International linkages will also be important to draw on the knowledge of gambusia control practices outside of Australia.
9C. Opportunities for end-user involvement End-users include key government bodies, scientific experts, mangers, interest and user groups involved in the control and monitoring of gambusia, as well as the general public. End-users will participate in most aspects of the project where direct liaison will be undertaken to determine current control program practices and available knowledge concerning management of gambusia.
10C. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating results of the project to the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users. This will include a comprehensive web-based information package, standard protocols for monitoring of control programs, and a database to document information relating to control programs. A key aim of the project is information dissemination.
11C. Estimated cost and duration Part A Short Term = 1.5 years Cost =$150 000
Part B Short Term = 0.5 years Cost =$50 000
Part C Short Term = 1 year Cost =$70 000
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PART 12D Determination of the distribution of Gambusia In order to develop strategies to deal with potential threats posed by gambusia it is essential to know where they have become established and the extent of their spread. Without this basic knowledge, coordinated and effective management and control strategies for gambusia is not possible. Despite some general aquatic monitoring programs that are currently in place, information on the presence and distribution of gambusia is often unavailable, as these programs are not designed to explicitly target gambusia or other alien species. Many surveys have targeted particular fish species and are often geographically restricted. Although some accessible state databases have been developed from combined survey results (e.g. DNRE fish database) much of the information remains disparate.
There is a need to identify gaps in knowledge of the distribution and abundance of gambusia in the MDB and address them by either adding value to existing survey programs or establishing programs to delineate the current distributions of gambusia. Existing survey programs and the quality of the data they contain will need to be reviewed. Furthermore, there is no doubt that the spread of gambusia is assisted by human activities. Monitoring the spread of gambusia in conjunction with a dedicated education program, which aims to change behaviours that assist spread, allows the effectiveness of the education program in reducing the spread of invasions to be directly tested.
3D. Project Objectives • To clarify the distribution and abundance of gambusia in areas where this information is incomplete and identify areas where the species does not appear to occur.
4D. Key Tasks • Review and summarise existing information on the distribution of gambusia within the MDB. • Determine whether any assessment can be made concerning the abundance of gambusia in habitats across the MDB (e.g. areas of high, medium and low densities). • Identify knowledge gaps in the existing distribution of gambusia within the MDB. • Contribute to existing programs to increase the information potentially provided on the distribution of gambusia. This may involve providing input into the planning stages of monitoring programs associated with habitat rehabilitation to ensure that gambusia are considered and identified. • Initiate strategic targeted surveys to clarify the distribution and abundance of gambusia in priority areas (e.g. at the edge of their distribution). • Promote techniques for monitoring programs which can effectively survey gambusia. For example, gambusia are usually found in slow-flowing areas at the edge of waterbodies and so survey techniques can be selected to effectively sample these habitats.
5D. Anticipated Products • Accurate distributional information in the form of maps will be added to the MDBC GIS system and to comprehensive databases. • A list of priority areas where gambusia do not occur, occur in low densities or are recent introductions.
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• Adding value to existing data by selected further processing of this data. • Recommendations on programs to fill existing knowledge gaps in the distribution of gambusia. • Contributions to relevant data bases, in particular information available through MDBC Web site.
6D. Anticipated Outcomes • An improved knowledge of the distribution of gambusia in the MDB that is easily accessible to end- users and that may assist in determining priority areas for management and control. • Up-to-date distributional information on gambusia that can contribute to rapid response and risk assessment strategies as well as education programs, particularly in areas where they currently do not occur or are recent introductions.
7D. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. Knowledge management is an essential component in the management and control of pest species such as gambusia.
8D. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, land and water management authorities, scientific experts, state and private agencies involved in environmental surveys and all other groups involved in the management of invasive species within the MDB and Australia. Links to education programs and projects concerned with risk assessment and rapid response strategies should also be an integral part of this project. This project represents targeted research relevant to these end-users as well as having a broader relevance to the general community and numerous interest groups.
9D. Opportunities for end-user involvement End-users involve key government bodies, scientific experts and land and water managers involved in the management of invasive species within the MDB and Australia and ultimately the general community given that the results of this research may lead to modifications in determining the distribution and management of gambusia.
10D. Mechanisms for transfer and adoption • Liaison with MDBC, state and federal agencies and scientific experts to review and collate all information available on the distributions of gambusia. • The information collected from this project will be accessible to all end users.
11D. Estimated cost and duration Short to Medium Term = 2-3 years Cost =$200 000 (nb: Costs will depend on the level of targeted surveys required).
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PART 12E
Targeted Research on the Biology and Ecology of Gambusia While gambusia is now widespread and abundant in the MDB their impacts on native fauna and environments is not well understood. Introduced species often occur in degraded environments and it is difficult to separate their impact on native fish and amphibian species from that of other variables. Gambusia have potential to compete and predate upon a range of species and targeted research is required to clarify and quantify impacts including what variables influences the significance of the impact. There have been specific concerns over the role of gambusia in the decline of amphibian species, particularly members of the L. aurea. However, evidence is limited, due in part to conflicting findings and limitations to the methodology of some studies. There is also some evidence that gambusia can cause reductions in some species of aquatic invertebrates through differential predation. In controlled experiments gambusia have been shown to predate upon small fish as well as affect their ability to grow and reproduce.
In addition to direct impacts of gambusia, on the environment factors that influence their distribution and abundance within the MDB are not well known. Gambusia do not appear to favour undisturbed lotic systems with naturally variable discharge regimes. An improved understanding of environmental conditions which favour as well as disadvantage gambusia will assist in improving management of aquatic systems to control the species.
Targeted research to fill key knowledge gaps on aspects of ecology and biology of gambusia will enable an improved approach to management of the species to restrict its impacts and limit its distribution within the MDB. This project brief identifies key research that is needed regarding gambusia and also the theory of targeting research towards threatened species and species with significant overlap in habitat range to gambusia.
3E.Project Objectives Impacts on native species - Predation • To investigate whether gambusia prey on a range of native species with which they coexist. Quantify the impacts of predation on the survival of populations of native species, and quantify the factors which influence levels of predation (e.g. habitat structure, pool size, flow regime, timing of breeding of native species and gambusia, sizes of life history stages most at risk). This should include a range of native fish and amphibian species and investigate which life history stages are at most risk. It should also include investigation of survival strategies of native species which may reduce the risk of predation (e.g. whether they exhibit avoidance behaviour etc.). • To determine whether gambusia has played a role in the decline of native species, particularly threatened species, and if so the significance of this role. • To determine the impacts of gambusia on the composition and abundance of invertebrates in different environments and environmental conditions. • To investigate whether a range of native species prey on gambusia with which they coexist. Determine whether gambusia are unpalatable to any species and/or whether any native species avoid preying upon gambusia.
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Impacts on native species - Competition • To investigate habitat and resource usage between gambusia and a range of key threatened species to determine the degree of overlap in habitats and resources. This could include studies of the feeding habits of native fish species and gambusia to quantify the degree of potential overlap in diets. Such experiments could investigate whether food is a limiting resource. This could include determination of whether native fish species and/or gambusia alter their feeding niches breadth in response to each other and the availability of food. • To investigate factors which influence aggressive behaviour of gambusia towards native species (e.g. density and space dependent, size of native species). Determine whether aggressive behaviour of gambusia varies towards different native species and the responses of native species towards gambusia. • To investigate how aggressive behaviour by gambusia affects native species (e.g. breeding success, growth, metabolic processes, infections and death).
Habitat preference of gambusia • To determine whether predation or competition by gambusia acts synergistically with other environmental factors such as habitat quality to the detriment of native species. • To investigate the habitat preferences of gambusia to obtain a better understanding of those factors which influence their distribution and abundance in the MDB (e.g. presence and abundance of aquatic vegetation, flow regime, etc.). • To compare the distribution and abundance of gambusia in undisturbed and disturbed habitats to gain a better understanding of what habitat conditions influence their presence. • To investigate the dispersal behaviour of gambusia to gain a better understanding of how they may invade different habitats and the factors which influence the effectiveness of dispersal. • Investigate how populations of gambusia respond to flooding (e.g. monitoring of populations before and after flooding events and comparisons of fish community structure). • To monitor aquatic systems at early stages of invasion by gambusia and habitat disturbance to determine whether habitat disturbance is a key factor in the establishment of such introduced species.
Parasites and diseases of gambusia • Determine whether gambusia populations at the margins of established or recently translocated populations are subject to environmental stress and prone to parasitism. • Investigate the parasites and diseases of gambusia to gain a better understanding of whether the apparent lower number of parasites and diseases associated with this species in comparison to native species provides gambusia with a competitive advantage.
4E. Key Tasks The key tasks to be undertaken will depend on the specific research questions selected from the above objectives. Where appropriate, research should include a mixture of controlled laboratory and field studies. Experiments should focus on mesocosyms to maximise their applicability to those conditions experienced in the field.
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• Conduct a mixture of short and long term behavioural and coexistence experiments to determine factors which may influence behaviour (e.g. space, habitat components, environmental conditions, etc.). • Conduct surveys to compare distribution and abundance with habitat condition characteristics. These surveys could also be conducted after manipulation of flow regimes in the field. • Conduct a mixture of short and long term experiments to determine rates of predation and dietary preference of gambusia and native species. • Conduct experiments to test for prevalance of parasites and diseases of gambusia in the wild as well as susceptibility trials.
5E. Anticipated Products • Specific products will depend on the research undertaken. • Reports including scientific papers for publication in journals will be produced.
6E. Anticipated Outcomes Outcomes will depend on the research undertaken, but will generally lead to: • An improved understanding of the impacts gambusia has on native fish, amphibian and invertebrate species. • The ability to separate the impact of gambusia on native fish, amphibian and invertebrate species with other variables such as habitat degradation. • An improved understanding of the factors which limit the range of gambusia in the MDB (e.g. high river discharges, undisturbed areas).
7E. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. Knowledge management is an essential component in the management and control of pest species such as gambusia.
8E. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, industry and interest groups, scientific experts and universities involved in fish behaviour, habitat and dietary preference research with the opportunity for students to conduct lab and field experiments.
9E. Opportunities for end-user involvement End-users involve key government bodies, scientific experts and universities involved in fish behaviour, habitat and dietary preference research.
10E. Mechanisms for transfer and adoption • Liaison with the MDBC education unit to assess appropriate methods for disseminating the results of the project to the community. • The steering committee will include appropriate representatives from end-users
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• The range of information concerning the project will be disseminated to end-users with the publication of reports of the results of experiments and published papers in scientific journals.
11E. Estimated cost and duration Short to Medium Term = 2-3 years Cost = $150 000/year/research project (nb: It is difficult to determine costs since it will depend on specific research issues to be investigated).
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PART 12F
Investigation of Potential Biological Control Technologies for Gambusia The primary aim of most control programs is to eradicate a pest species from an area. In many cases, particularly for widespread and abundant species such as gambusia, eradication is extremely difficult if not impossible. There are a range of methods used to reduce numbers of pest species, most of which are expensive and labour intensive, require substantial ongoing commitments to be effective, may cause environmental contamination and social concerns and may affect non-target species. There are currently no broadscale effective and acceptable methods to control gambusia in aquatic environments.
Research into biological control is now becoming a major focus to control programs for a range of fauna species. Potential benefits to biological control include being species specific, long lasting, and cost effective in terms of delivery and spread. Biological control may represent a technique that will potentially lead to eradication of pest species such as gambusia. Some research has recently been undertaken by CSIRO on biological control techniques for freshwater fish species in Australia. The technology involves altering the sex ratio of fish populations so that the species effectively breeds itself out of existence. While this technology is being developed for species such as carp, it is broadly applicable to a range of taxonomic groups. The current technology has been developed to the proof-of- concept stage using zebra fish as a short-lived organism. Work is still required to transfer the technology to other species including testing in controlled populations in the field (e.g. isolated ponds), developing optimal release and monitoring strategies, consulting the community about the technology and its use and ultimately releasing the construct into populations. Gambusia is considered to be a suitable species to trial because of its short life cycle and it is believed that field trials could be undertaken in 3-4 years (Peter Craig, CSIRO, pers. comm.).
Project 17 "Development of biological control technologies for pest species' outlines in detail the background research which has already been undertaken by CSIRO in Tasmania on the development of genetic technologies for pest fish species. The technology already developed is applicable to species such as gambusia and further development and trialing of this methodology is required. The details concerning objectives, tasks, products, outcomes and costings of investigating genetic technologies for gambusia are outlined in Part A of Project 17.
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7.4.13 Research Project Brief 13: Testing the Effectiveness of Carp Eradication and Control Techniques
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2b) Community education • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies Since their rapid spread in the 1960s controlling the abundance of carp (Cyprinus carpio) has challenged river managers. Carp are now widely distributed across the MDB where they often dominate the biomass within fish communities. Carp have caused major detrimental impacts on aquatic biodiversity and also on social, agricultural and aesthetic values. In the last decade critical evidence has been collected on the life history of carp and in particular their use of floodplain wetlands as important spawning and recruitment habitats. Consequently, through using best management practices for vertebrate alien species, a greater range of control options can be tested to reduce carp abundance within key areas of the MDB.
Although there are some instances of intensive control efforts many past carp control efforts have been undertaken in an ad hoc manner and consequently reducing the spread of carp or eradicating them from relatively small areas has been problematic. Several existing projects in South Australia, Tasmania and Victoria have made some progress in research to control carp numbers. However, the continued spread of carp into new catchments highlights an urgent need for more effective control techniques. Following the release of the National Management Strategy for Carp Control (MDBC 2000), the Guide for Carp Management Groups (Braysher and Barrett 2000) and recent results of applied research, there is renewed momentum to develop and trial specific control techniques aimed directly at the fish itself. Effective control methods will be important for reducing the spread and impacts of carp in a range of habitats and integration of these plans with other restoration efforts have the potential to reduce carp impacts. However, although there is a strong desire amongst stakeholders to implement existing carp control techniques there is little practical knowledge to support such actions.
Identification of priority areas for carp control within the MDB, particularly those where carp threaten significant community or biodiversity values and a broad range of eradication trials should be investigated. Pilot eradication and control trials, using best practice techniques, can then be tested in conjunction with monitoring to assess their effectiveness. These techniques may include wetland screening, drawdown of spawning areas and behavioural barriers to migration. Results from these trials can then be assessed and practical operating codes of conduct developed for future control efforts for a broad range of groups involved in carp eradication programs. Improved information transfer of field tested techniques would then provide a significant level of logistic experience for ensuing control programs.
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3. Project Objectives • To quantify the success of a targeted large-scale carp control program. • To provide guidelines to river managers, community groups and commercial fisherman for carp control options and operating standards. • To develop techniques for carp control that are broadly applicable in the MDB.
4. Key Tasks • Collate relevant literature (such as: Koehn et al. 2000, Roberts and Ebner 1997) and expert opinion from Australia and overseas concerning field tests of eradication and control measures for carp. • Establish a multi-disciplinary team including river managers, scientists, commercial fisherman and community groups to facilitate well-targeted field trials and address relevant policies and procedures. • Identify key biodiversity areas within the MDB which are threatened by carp (including areas where there is an imminent threat of introduction) and priority areas for control trials and environmental rehabilitation (such as Ramsar sites). • Review control and eradication techniques in terms of cost, feasibility and practicality in relation to the key habitat areas, particularly where there are some existing data. • Identify carp control techniques which are likely to have a high chance of success, are socially and environmentally sound, and may be widely applicable in the MDB. • Identify benefits and threats to these key areas by the implementation of carp eradication or control efforts and a standard set of performance criteria (i.e. eradication, habitat improvement, changes to biodiversity). • Assess existing programs in Australia which give a greater time-scale to carp control efforts such as the carp control efforts in Lakes Sorrel and Crescent, and the wetland screening studies in South Australia. • Pilot test a monitoring and carp control program and assess its effectiveness against a series of performance indicators. • Undertake and quantify the success of a targeted large-scale carp control program. • Provide guidelines to river managers, community groups and commercial fisherman for effective, cost efficient and socially acceptable carp control options, operating standards and resource priorities. • Promote carp control efforts and community involvement in the long-term control program.
5. Anticipated Products • A comprehensive and critical review of past and emerging control techniques for carp (an other invasive fish) within the MDB. • Development and testing of eradication techniques for reducing the spread and abundance of carp at key areas in the MDB. • A series of guidelines for groups undertaking practical carp control efforts.
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6. Anticipated Outcomes • An improved understanding of the effectiveness of control techniques for alien fish species in the MDB. • An improved level of public awareness of the problems caused by invasive fish in the MDB and a strategy for community participation in carp control.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Direct linkages of the project and outcomes between key government agencies, scientists, professional fisherman, councils and peak angling bodies will be available. The project may also forge links with the National Carp Task Force, the National Feral Animal Control Program of Bureau of Natural Resources and other agencies involved in pest species management.
9. Opportunities for end-user involvement End-users involve key government bodies across the MDB, land and water management agencies, scientists and other research agencies involved in pest species management. A major user group will be community based Landcare and angling groups who will be involved in most aspects of the project.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating results of the project to the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users. This will include guidelines for groups undertaking practical carp control efforts. • The National Carp Task Force, state fisheries agencies and water resource managers will also play a role in transfer and adoption of information.
11. Estimated cost and duration Medium Term = 3 years Cost = $300 000/year (nb: this includes some seed funding for carp control groups and monitoring).
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7.4.14 Research Project Brief 14: Determination of the Distribution of Alien Species
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats • M2c) Knowledge management
2. Context, and how this addresses key management issue(s), strategies or policies Biological invasions are increasing through time on a global scale via deliberate and accidental human dispersal. Local regions such as the MDB continue to be affected by an ever increasing rate of invasions. In order to develop strategies to deal with potential threats posed by alien species it is essential to know which invading species have become established and the extent of their spread. Without this basic knowledge coordinated and effective management and control strategies for invasive species are not possible.
Despite some general aquatic monitoring programs that are currently in place, information on the presence and distribution of alien species is often unavailable, as these programs are not designed to explicitly target alien species. The types of surveys carried out in the MDB for groups such as macroinvertebrates, fish and plants, ranges from general to species specific surveys and vary broadly in approach, intensity and scale. These differences contribute to the difficulty of determining the presence and extent of invasive species within the basin.
The national AUSRIVAS program, which uses macroinvertebrates for monitoring stream health, has the advantage of being a long-term, standardised survey with all information collated into centralised, accessible databases. However information is somewhat limited in that macroinvertebrates are only identified to family level therefore obscuring any specific information about the presence of alien invertebrate species. Various fish surveys have been undertaken including the NSW Rivers Survey (NSW Fisheries), however many surveys have targeted particular fish species and are often geographically restricted. Although some accessible state databases have been developed from combined survey results (e.g. DNRE fish database) much of the information remains disparate. Consequently our knowledge of the distribution and abundance of many invading fish species is poor. No adequate monitoring programs are currently in place for aquatic plants and invasive species have not been targeted systematically despite the potential for some to cause significant environmental and economic impacts.
There is a need to identify gaps in knowledge of the distribution and abundance of particular alien species in the MDB and address these by either adding value to existing survey programs or establishing programs to delineate the current distributions of these species. In order to identify these knowledge gaps existing survey programs and the quality of the data they contain need to be reviewed with a particular focus on the presence and distribution of invasive species. For example, databases and macroinvertebrate samples from the AUSRIVAS program can be reviewed and examined in order to determine the presence of alien species. This process would entail re-identification of reviewed specimens and may engage the expertise of specialists for the determination of alien species that are morphologically similar to native species e.g. Hydrobiidae snails. For other species, in particular for some fish and aquatic plants,
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a greater investment may be necessary to gather the basic data required for identifying and dealing with the threat of biological invasions in the MDB. This investment may entail new surveys specifically developed to target aquatic invaders, however it may be possible to identify areas that may be at higher risks of invasion by these species and specifically target these areas in directed surveys. For example, as the aquarium trade is of particular importance as a transport vector for aquatic plants and for some fish, areas downstream of urban areas may be particular vulnerable to invasion by these species. On the other hand, given potential similarities in the habitat of aquatic invaders, a wide range of species can be targeted simultaneously within one sampling program.
The distribution of alien species are clearly likely to change through time and there is a need to develop efficient and effective programs that monitor such change. Programs can be general and target a range of species, with associated economies of scale. At a more intensive level some invasive species, such as weatherloach, can be targeted directly to establish the pattern of their continuing spread from existing, known populations. Furthermore, there is no doubt that the spread of alien species is assisted by human activities. Monitoring the spread of particular alien species in conjunction with a dedicated education program, which aims to change behaviours that assists spread, allows the effectiveness of the education program in reducing the spread of invasions to be directly tested.
3. Project Objectives The project has three stages:
Stage 1 The first stage of the project is a review and summary of the information available on the distribution of alien species within the MDB from existing surveys, reports and data. In some cases little additional effort may be required (such as re-examination of existing e.g. AUSRIVAS samples to identify individuals to species level) to gain substantial additional information. This stage of the project will allow specific gaps in our knowledge of the distribution of potentially important alien species to be identified. Given that some existing surveys also include measures of environmental variables it may be possible to specifically test hypotheses regarding the presence or absence of invaders in relation to environmental variables.
Stage 2 The second stage of the project will directly target specific knowledge gaps in the distributions of particular alien species. For example, invasive aquatic snails and plants may be particularly likely to colonise areas downstream of urban regions with aquarium trade activities. Knowledge of the distribution of other invasive species, e.g. snails such as Fasciola hepatica which carry sheep liver fluke, may be crucial to target in areas where livestock are threatened by these parasites.
Stage 3 The third stage of the project is concerned with the continuing spread of alien species. It will lead to the development of a strategic plan for updating our knowledge of the distribution of alien species within the MDB. If education programs regarding the spread of alien species are in place this part of the project provides the opportunity to collaborate with these projects and also test their effectiveness. It may also
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be possible to form links with future or existing habitat rehabilitation programs within the basin to assess whether these actually reduce the distribution of alien species.
4. Key Tasks Stage 1: • Review and summarise existing information on the distribution of alien species within the MDB. • Identify knowledge gaps in the existing distribution of alien species within the MDB. Given the potentially high number of invading species it will be necessary to prioritise particular species, groups of invading species or particular areas for which we require more distributional information. However, this selection process needs to be firmly based on scientific principles. Forming a target list of invaders or habitats that we require more knowledge about must be done in an open and scientific manner under strict criteria. It may be particularly relevant to target areas where processes that increase the spread of invasive species are prevalent e.g. by looking at conceptual models of invasion. In other cases, known or suspected impacts of particular invading species may provide a criterion for targeting particular species. • Contribute to existing programs to increase the information provided on the distribution of alien species. This may involve re-examining selected samples collected in large-scale monitoring programs, such as AUSRIVAS, and determining if invasive species are present in these samples. It may also involve providing input into the planning stages of programs, such as monitoring programs associated with habitat rehabilitation programs, to ensure that particular invasive species are considered and identified. By introducing a specific emphasis on invading species into other environmental management programs value can be added to these programs at minimal cost.
Stage 2: • Build on a target list of invading species or target areas as identified in stage 1. • Develop specific programs to determine distribution of alien species to clearly identify the extent of invasions by particular species in the MDB and/or the extent of biological invasions in particular, targeted areas. The development of these programs provides unique opportunities to test particular hypotheses regarding the distribution and spread of invading species. For example, the connection between the spread of invaders and transport opportunities provided by anthropogenic activities can be directly examined, as the MDB includes areas that may be greatly affected by human activities as well as areas that are less affected. • Develop strategic monitoring programs that aim to provide information on as many invading species as possible within the same program. In collaboration with risk assessment programs, priority may be given to invading species likely to cause the greatest impacts, or to areas likely to be most affected by biological invasions. Special consideration needs to be given to the selected survey techniques, as some may need to be adapted to include particular taxonomic groups or habitats.
Stage 3: • Develop and/or add to existing survey programs so that our knowledge of the distribution of alien species is continuously updated, therefore accounting for temporal changes.
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• Combine collated distributional data with experiments that test the effectiveness of strategies designed to reduce the spread of alien species. This can be achieved through collaboration with other programs, such as an education program on pest fauna and flora in the MDB, for example: ! The proposed education program suggests changing behaviours that unintentionally contribute to the spread of invasive species throughout the basin. By surveying the distribution of particular invading species both before and after the implementation of such a program, including areas where the education program has and has not been implemented, it may be possible to test whether the education program has contributed to reducing the spread of invasive species. • Gathering distributional data may add value to existing environmental management programs by collaboration with current projects e.g. habitat rehabilitation through monitoring the effects of these programs on invasive species. It is not clear whether rehabilitation programs need to incorporate invasive species removal or if invaders are less likely to remain successful in maintaining populations in rehabilitated areas. Collaboration and monitoring may provide this valuable information on the effects of habitat rehabilitation on invading species.
5. Anticipated Products Stage 1: • Accurate distributional information in the form of maps and comprehensive databases on the presently known distributions of particular alien species within the MDB. • Adding value to existing data by selected further processing of this data. • Recommendations on programs to fill existing knowledge gaps in the distribution of alien species. • Contributions to relevant data bases, in particular information available through the web site of the MDBC. However, as biological invasions are a global problem contributing information to selected international databases, such as ones linked to the IUCN, should also be considered.
Stage 2: • Provision of a comprehensive update on the current distribution of alien species in the MDB through elimination of current knowledge gaps. This information will be added to the MDBC GIS system and to relevant databases. • Information such as maps and databases need to be available to a broad audience
Stage 3: • Development and implementation of strategies and programs for maintaining and updating our knowledge of the distribution of alien species in the MDB. • Experimental tests of the effectiveness of programs, such education or habitat rehabilitation programs, in reducing the spread of alien species within the basin.
6. Anticipated Outcomes • An improved knowledge of the distribution of particular invaders in the MDB that is easily accessible to end-users. • Up-to-date distributional information on invading species that can contribute to rapid response and risk assessment strategies as well as education programs.
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• Adding value to other programs by testing hypotheses related to the distribution and spread of invading species.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan. Knowledge management is an essential component in the management and control of pest species.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, land and water management authorities, scientific experts, state and private agencies involved in environmental surveys and all other groups involved in the management of invasive species within the MDB and Australia. Links to education programs and projects concerned with risk assessment and rapid response strategies should also be an integral part of this project. This project represents targeted research relevant to these end-users as well as having a broader relevance to the general community and numerous interest groups.
9. Opportunities for end-user involvement End-users involve key government bodies, scientific experts and land and water managers involved in the management of invasive species within the MDB and Australia and ultimately the general community given that the results of this research may lead to modifications in determining the distribution and management of invasive species.
10. Mechanisms for transfer and adoption • Liaison with MDBC, state and federal agencies and scientific experts to review and collate all information available on the distributions of exotic species. • The information collected from this project will be accessible to all end users.
11. Estimated cost and duration Stage 1 Medium to Long Term = 3-5 years Cost = $150 000 to $300 000/year
Stage 2 Medium Term = 3 years Cost = $100 000- to $150 000/year
Stage 3 Medium Term = 3 years Cost = $100 000- to $150 000/year
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7.4.15 Research Project Brief 15: Assessment of Ecological Impacts of Alien and Exotic Species
1. Key Management Issue(s) (as identified in the RESP) • 4Rd) Managing threats to communities and habitats
2. Context, and how this addresses key management issue(s), strategies or policies There are numerous alien and exotic flora and fauna species in aquatic and riparian habitats within the MDB which are current or potential pests. Invasive species may be detrimental to native flora and fauna communities and environments, they may alter ecological processes, cause declines in water quality, introduce pathogens, hybridise with native species and also have economic or social impacts. Invasive species may compete with natives for resources such as space and food, restrict reproduction and growth, as well as predate upon them.
Our knowledge of the impacts of a range of invasive species on the environment and biodiversity within the MDB is patchy. While there is some conclusive information concerning particular impacts (e.g. predation of native galaxiids by trout), the types and significance of other impacts of invasive species is either implied, suspected through anecdotal evidence or entirely unknown. There is a need to identify key knowledge gaps concerning the impacts of those invasive species which are known or believed to be of greatest concern within the MDB. Undertaking research to fill key knowledge gaps will enable a more targeted approach to identifying and managing those species which are known to have detrimental impacts on the environment and biodiversity. Without key pieces of information concerning impacts of invasive species, appropriate management of such species is extremely difficult and cannot be supported by sound evidence.
The results of a recent questionnaire associated with MDBC project R2006 (see main report), and a review of existing literature has highlighted a range of knowledge gaps in relation to the impacts of pest species on native flora and fauna communities and environments. This project aims to address key knowledge gaps in interactions between native species and invasive species considered to be a priority for management. It can also identify priority areas where research should be focused (e.g. areas where significant populations of native species occur). It should involve a series of targeted experiments to clarify the specific impacts of these invasive species including quantification of impacts, what environmental factors influence impacts etc. Targeted research could be undertaken on species such as carp and gambusia; while these species are already widespread and abundant within the MDB, we do not know whether they are significant predators of eggs and larvae a range of native species. For other species such as weatherloach which are gradually spreading across the MDB, we have minimal information on their possible impacts to native species.
A clear understanding of the impacts of invasive species on native species will enable an accurate determination of the implications of these invasive species on the survival of native species. An emphasis can also be placed on threatened native species which may be most vulnerable to impacts.
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This project brief is necessarily general in its tasks. Once the initial step of determining key knowledge gaps and priority proposals for targeted experiments is undertaken, this will then enable clear research projects to be undertaken.
3. Project Objectives • To identify key knowledge gaps for invasive flora and fauna species which are most likely to cause significant detrimental impacts to environments and biodiversity within the MDB. • To undertake targeted research to improve our understanding of the impacts associated with key invasive species and to ensure that management of these species is targeted and based on sound knowledge.
4. Key Tasks • Identify key invasive flora and fauna species on which to undertake research, based on the advice of key scientists and managers involved in the issue of pest management within the MDB. This should build on opinions already received from the recent questionnaire distributed as part of this MDBC scoping study. • Further review/summarise current information of these key invasive species relating to their ecology and impacts on native species and environments. • Formulate specific hypotheses regarding the possible effects of invasive species that can be tested experimentally. This should include identification of assumptions with these hypotheses to enable these to be tested. • Develop and undertake experiments to test hypotheses. These may include laboratory and/or field trials. The use of mesocosms should be given priority to imitate natural conditions. Such trials could investigate and quantify competitive interactions, predation, shifts in niches and behaviour etc. • Interpret the results of experiments to clarify the impacts of these invasive species on native species and habitats with the aim of developing recommendations for the appropriate management of these key invasive species within the MDB. • Develop appropriate educational material to ensure that the information obtained from this research is disseminated to those involved in the management of invasive species as well as interest and user groups and the general public.
5. Anticipated Products • Experimental tests of hypotheses regarding the impacts of key invasive species on native species and habitats within the MDB. Reports will be prepared on the findings of these experiments for the MDBC and appropriate scientific journals. • Recommendations concerning the appropriate management of key invasive species within the MDB. • Educational material explaining the impacts of invasive species for those involved in the management of invasive species as well as interest and user groups and the general public.
6. Anticipated Outcomes • An improved understanding of whether key invasive species within the MDB have detrimental impacts on native species and habitats, including the types of impacts and their significance.
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• Appropriate and targeted management actions to deal with these key invasive species within the MDB, based on sound scientific evidence. • An improved ability to manage these key invasive species and their invasion into new areas. • An improved understanding of the impacts of invasive species for those involved in the management of invasive species as well as interest and user groups and the general public.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientific experts and land and water managers involved in the management of invasive species within the MDB and Australia. The specific research projects undertaken will link directly to relevant and associated research projects currently being undertaken within the MDB and Australia by scientific bodies such as universities, CRCs etc. This project represents targeted research relevant to these end-users; the results however have a broader relevance to the general community and numerous interest groups (e.g. conservation groups, Landcare groups, farmers, anglers etc.).
9. Opportunities for end-user involvement End-users involve key government bodies, scientific experts and land and water managers involved in the management of invasive species within the MDB and Australia and ultimately the general community given that the results of this research may lead to modifications in management of particular species.
10. Mechanisms for transfer and adoption • Liaison with the MDBC education unit to assess appropriate methods for disseminating the results of the project to the community. • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users with the publication of reports of the results of experiments and published papers in scientific journals.
11. Estimated cost and duration Medium Term = 3 year projects It is difficult to determine a specific cost to targeted experiments, although an average cost per project could range between $100 000 - $150 000/year
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7.4.16 Research Project Brief 16: Research and Management of Exotic Pathogens
1. Key Management Issue(s) (as identified in the RESP) • R4d) Managing threats to communities and habitats
2. Context, and how this addresses key management issue(s), strategies or policies The impacts associated with invasive species often focus on biotic interactions such as predation and competition, or on physical effects, such as habitat swamping. However, pathogens associated with invasive species also have the potential to pose serious threats to native aquatic species, such as fish, both in the wild and in cultured conditions (e.g. hatcheries, aquarium trade). They may cause mortalities, producing obvious fish kills or have sublethal effects which could affect long-term survival and reproduction which are generally more difficult to detect.
There are a number of diseases and viruses that have been recorded in native, alien and exotic fish species in the MDB. Little quantitative data is available about the prevalence of these pathogens in the wild, nor about the impacts of these pathogens on native fish species. Those of particular concern include the Epizootic Haematopoietic Necrosis Virus (EHNV), Goldfish Ulcer Disease, Viral Encephalopathy and Retinopathy (VER) formerly known as the Barramundi virus, and the Asian Fish Tapeworm. EHNV has only been recorded in Australia and can cause sudden high fish mortalities. Viral Encephalopathy and Retinopathy can cause mass mortalities of farmed barramundi and there are concerns that it may be accidentally released into the wild. Goldfish Ulcer Disease has caused fish mortalities in hatcheries and in the wild. Asian Fish Tapeworm is a parasite that has been recorded in the wild within a number of native and introduced fish species and its impacts on hosts in Australia are not well understood. Both native, alien and exotic fish species may potentially act as hosts and/or carriers of such diseases and viruses, which is of particular concern given that several species of alien and exotic fish are widespread and abundant across the MDB.
Limited research has indicated that several native, alien and exotic fish species are highly susceptible to some diseases and viruses (e.g. Langdon 1989, Glazebrook 1995), but our knowledge of these diseases and viruses is patchy. Further information is required on the prevalence of the diseases in the wild and which species may act as hosts and carriers, on the susceptibility of numerous species to these pathogens, on the factors which influence species’ susceptibility, and on impacts of the pathogens on their hosts, including both lethal and sublethal effects. An improved understanding of these key knowledge gaps will enable more appropriate management of the threat of pathogens based on a suitable knowledge base.
This project may be separated into several components, which could be funded individually. They concern reviews of information, targeted research and policy/management.
3. Project Objectives • To determine the susceptibility of a range of native, exotic and alien fish species to pathogens which already occur within the MDB. • To determine the prevalence of these pathogens and their effects in the wild.
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• To identify those pathogens and associated diseases of greatest concern to MDB biodiversity, which are not yet present, but may potentially enter Australia.
4. Key Tasks Review • Review/summarise existing information on pathogens that are known to cause disease in fish in Australia and the MDB. This includes information on the origin and Australian distribution of the pathogens, on known transmission pathways, and on the susceptibility of native, exotic and alien and introduced fish species to infection by these pathogens under both natural and captive conditions (e.g. hatcheries and aquarium industry). • Survey the prevalence of pathogens and resulting fish diseases of greatest concern within cultured conditions across the MDB and assess the potential likelihood of accidental release of these pathogens into the wild. • Review/summarise pathogens and diseases known to occur in other countries which may potentially be introduced into Australia, either accidentally or deliberately and which are considered likely to be of greatest concern. • Contact key researchers and managers within Australia and overseas to obtain their advice concerning particular pathogens and diseases, their prevalence and possible importance as a threat to native fish species. • Identify which fish pathogens and diseases require further research based on those of most concern within Australia and most specifically within the MDB. This may include Epizootic Haematopoietic Necrosis Virus (EHNV), Goldfish Ulcer Disease, Viral Encephalopathy and Retinopathy (VER), and the Asian Fish Tapeworm.
Research • Identify key knowledge gaps which require further research in relation to fish pathogens and diseases. For example, which significant fish species (native and/or introduced) should be the focus of susceptibility trials, which may act as hosts and carriers and methods of transmission. • Undertake research to fill these knowledge gaps. Susceptibility trials should investigate both lethal and sublethal effects. • Determine the implications of the results of this research in relation to the threats these pathogens pose to native fish species within the MDB. • If this research indicates particular pathogens are of significant concern, it may be appropriate to undertake targeted surveys to determine the prevalence of those pathogens and/or associated diseases in the wild.
Policy and Management • Identify obstacles which may limit our current ability to determine the prevalence of pathogens in the wild and determine possible methods to address these obstacles. Develop a standard protocol for the rapid reporting of fish kills within the MDB. Currently, fish kills are often reported in a vague fashion and there is no consistent methodology in place across the MDB to ensure a rapid response to fish kills. This should build on existing procedures such as the NSW Fish Kill Register. Furthermore, reasons for fish kills can rarely be attributed to a specific cause. The establishment of a
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rapid response protocol would enable rapid and effective testing of dead fish to determine whether they could be attributed to particular pathogens or to some other factor. The establishment of a coordinated rapid response process can contribute to our knowledge of the prevalence of pathogens and diseases in the wild and their impacts on fish species. • Review existing policies and management in relation to the presence of pathogens under cultured conditions and the potential for their accidental release into the wild. Determine whether any modifications of existing procedures are required to further minimise risks of accidental introduction of pathogens into the wild. • Identify appropriate management actions to address the introduction, spread and potential prevalence of diseases in the wild. For example, a rapid response plan could include a requirement for early documentation of reports of diseases in the wild and recommend appropriate procedures for rapid control of new introductions. This task should build on existing approaches for the containment of pathogens (e.g. CSIRO Australian Animal Health Laboratory). • Identify priority actions to minimise chances of the introduction of such pathogens. This may include an educational campaign, liaison with key interest and user groups, investigation and monitoring of existing policies and procedures concerning importation of fish into Australia etc.
5. Anticipated Products • A comprehensive report reviewing pathogens and diseases both currently known to occur in Australia and the MDB, and those which potentially may enter the country and which are of most concern in terms of possible detrimental impacts. • A report incorporating the results of laboratory and field trials concerning the susceptibility of key species to diseases and viruses of most concern, known hosts and carriers, prevalence in the wild and in hatcheries etc. • A report reviewing the existing policies and management in relation to the presence of diseases and viruses under cultured conditions and whether any modifications are required. • A standard protocol for the rapid reporting and assessment of fish kills to determine whether they can be attributed to pathogens. • A rapid response plan to document and manage early reports of disease indicating the introduction of a pathogen into the wild. • A list of priority actions to minimise chances of the introduction and spread? of such pathogens.
6. Anticipated Outcomes • An improved understanding of the significance of the threat posed by pathogens in the MDB, particularly in relation to the role pest species may play in their occurrence and spread. • An improved understanding of the relationship between pathogens and fish diseases within the MDB. • A coordinated response to dealing with the occurrence and spread of diseases in the MDB, including minimising the likelihood of introductions.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issues within the Riverine Environment Strategic Plan.
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8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientific experts involved in the detection and management of diseases, user groups such as the aquaculture and aquarium industry. International linkages will also be important to draw on the knowledge of diseases and their management elsewhere.
9. Opportunities for end-user involvement End-users involve key government bodies, scientific experts involved in the detection and management of diseases, and user groups such as the aquaculture and aquarium industry. They will be involved in all aspects of the project where direct liaison will be undertaken to determine the current and potential diseases of concern within the MDB and across Australia, the determination of their prevalence, testing of native, exotic and alien species and the minimisation of the threat of introduction and spread of diseases.
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating the results of the project to the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users. This will include comprehensive reports of reviews, the results of trials, standard protocols and rapid response plans.
11. Estimated cost and duration Medium Term = 2-3 years Cost = $250 000.
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7.4.17 Research Project Brief 17: Investigation of Potential Biological Control Technologies for Alien and Exotic Species
1. Context, and how this addresses key management issue(s), strategies or policies The primary aim of most control programs is to substantially reduce impacts of a pest species in an area. Eradication is rarely the goal because in many cases, particularly for widespread and abundant species, eradication is extremely difficult if not impossible using currently available techniques. Successful eradication of aquatic pests using existing technologies may be feasible only on a small scale in isolated waterbodies. For fish, even these small scale efforts often fail. To date, there are no practical options for controlling carp, gambusia, tilapia or any other introduced pest fish species, in larger water bodies in Australia or anywhere else.
There are a range of methods that can and have been used to reduce numbers and impacts of the range of pest species, most of which are expensive and labour intensive, require substantial ongoing commitments to be effective, may cause environmental contamination and social concerns, and may affect non-target species (Bomford and O’Brien, 1995). These include application of pesticides, environmental management and remediation, and selective harvesting (often subsidised). None of these techniques are widely applicable against established pests, for which biological control offers the preferred long-term solution. In relation to fauna, most work to date on biological control techniques has been on terrestrial species such as mice, rabbits, foxes and possums, as well as a very diverse range of insects (mainly agricultural pests). For flora species, potential methods include Classical Biological Control, which is defined as the introduction of a control agent into a region, that is not part of their natural range to suppress permanently the populations of selected target weeds.
Biological control techniques, using state-of-the-art technology, require significant commitments in resources and time, and are likely to involve a multi-disciplinary team to develop suitable methodologies. Biological control of insects typically requires 6 or 7 or more scientist-years plus supporting staff, while more effort is required for plants, e.g. 11 to 24 scientist years per weed pest in Canada (Harris 1979). Potential benefits of biological control include it being species specific, long lasting, cost effective in terms of delivery and spread, environmentally benign and publicly acceptable. While the investigation of biological control techniques requires a long-term commitment in resources, there is a significant potential for these techniques to provide a long-term saving in resources to control pest species. The average benefit to cost ratio of biological control in Australia has been 10.6:1 with a maximum exceeding 100:1 (Tisdell 1990).
Options for conventional biological control (that is, based on parasites or predators imported from a pest species native range to control the pest) have been investigated for a number of the pest fish species in the MDB. These include gambusia (work done overseas) and carp (see Crane and Eaton 1997; summarised in Koehn et al. 2000). No agents have been found that are likely to be safe (i.e. species- specific) and effective for any fish species, in Australia or overseas. The CSIRO is currently working with US biologists on a recently emerged, apparently carp-specific virus in North America, but note the rapid ability of fish to evolve resistance to such viruses and the uncertain likelihood that it would remain carp-specific in a new environment. 194 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
Over the last five years, CSIRO has invested $4 million to investigate whether modern genetic technologies can be used to control pest fish species. The “sterile ferals” project sought to develop a genetic technique that could be applied to exotic animals prior to importation, such that they could to be bred in captivity but would be sterile if they escaped. The project also examined whether a variant on those techniques could be used against existing pest species. The project focused, in particular, on carp.
Initial results have been promising. Laboratory trials indicate non-GMO (i.e. no foreign genes) genetic techniques could have very major impacts on target pest populations, with relatively little investment in effort and no risk to non-target species. First-generation genetic techniques have been tested successfully on zebrafish (a small, fast growing, close relative of carp). Further trials with zebrafish are underway. Realistically parameterised, but spatially simple carp population models indicate that the genetic techniques tested on zebrafish, if applied to carp, could result in very major reductions in carp numbers within 15-20 years of first release – the time span is largely a result of the presumed 30-yr maximum longevity of carp.
This project is separated into two distinct areas • Part A - Development of an integrated management plan for pest fish species, most notably carp and gambusia, based on genetic technology. • Part B - Investigation of biological control methods for a key plant pest, arrowhead Sagittaria.
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PART 17A Development of an integrated management plan for pest fish species, most notably carp and gambusia, based on genetic technology
2A. Project Objectives • To further develop and trial genetic techniques against carp and gambusia, in order to evaluate the efficacy and safety of control efforts, develop optimal release and monitoring strategies, and undertake a comprehensive and transparent risk assessment. • Using genetic approaches as the core of a control program, to develop a plan that integrates environmental management, commercial and community-based harvesting and genetic technologies to control, if not eradicate gambusia and carp from the MDB. • To consult extensively with all relevant stakeholders prior to the implementation of any control program, in the context of a fully transparent risk assessment framework. • To develop a consortium of relevant agencies to implement a control program against carp and gambusia, including at least the MDBC, the States, EA and the CSIRO.
3A. Key Tasks Application of genetic pest control technology to gambusia and carp requires four steps, each of which results in a greater ability to predict outcomes: 1. Proof-of-concept of the genetics and physiology, assessment of probable efficacy using simple population models and initial consultation with the public and key stakeholders over acceptability of the technologies. 2. Rigorous analysis of the genetics over several generations, trials in laboratory populations to test model predictions, field studies on the target species to develop accurate, spatially resolved risk analyses and optimal release and monitoring strategies, and detailed public dialogue about the technology and application based on the data as they become available 3. Field trials in small ponds or enclosures, to test the efficacy and safety of the system under natural, but controlled conditions 4. Release of ‘carriers” and monitoring of their impacts on the targeted pest population.
The CSIRO has completed Step 1: the genetics and physiology work, the models predict an effective control system, and public response to the broad concept, though full of questions, has been uniformly positive.
The rate of progress on Steps 2 through 4 depends on the biology of the target species, and particularly its generation time.
The CSIRO estimates that for gambusia (a fast growing, fast breeding fish), Step 2 will take about 3 years, and Step 3 another 3-4 years. The duration of Step 4 (release and monitoring) is difficult to estimate at this stage, as there are still considerable unknowns about the population genetics and biology of gambusia in Australia. However, given the rapid generation time of the species, effective control within ten years of first release is likely.
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For carp, a slower growing fish, Steps 2 and 3 overlap, as trial populations will have to be done in secure water bodies due to the large size of the fish. The combined effort will require at least 7 years. It is not yet possible to estimate time to effective control once the carriers are stocked out, as it depends on the stocking rate chosen, the extent to which complementary control actions (such as modification of flow regimes and community carp removal efforts) are undertaken, and unknowns about the population genetics of carp in Australia. Minimum time to effective control of carp is likely to be 20-30 years, however, given their long generation times.
A stepped approach to application of the technology allows for extensive public consultation, development of control plans that integrate the effects of complementary management actions, and a review of options at each stage prior to committing to the next step in the program. A stepped approach minimises risks (economic, biological or social) by providing an explicit review and public consultation process before moving on to the next step in the program.
Specific tasks which need to be undertaken for Steps 2 and 3 include: • Develop detailed, realistic models of carp and gambusia population dynamics and genetics, which can be used to predict the efficacy of genetic options for pest control, develop optimal release and monitoring strategies and form the basis for an integrated pest management plan. • Transfer the technology developed for zebrafish into carp and gambusia (a relatively quick process for the latter; slower for carp because of their longer generation time). • Undertake population-level trials - in the laboratory for gambusia (Step 2) and in secure field sites (isolated water bodies) for carp (Step2/3) and gambusia (Step 3) - to assess in detail the effectiveness and operating characteristics of genetic techniques under natural conditions, to test model predictions and refine the models, and to identify potential risk factors prior to wide scale control efforts. • Undertake extensive stakeholder consultation, which should include a transparent and comprehensive risk assessment process, an assessment of the potential benefits, costs, ethical and social concerns, and practicalities of widespread implementation of genetic control as part of an integrated pest control program, and an evaluation of legislation and appropriate policies and procedures.
Prior to Step 4 • Identify key priority areas within the MDB where potential methods should be first trialed. • Develop and implement a project management structure that involves at least the States, the MDBC, EA and the CSIRO, to oversee long-term control efforts.
4A. Anticipated Products • An environmentally safe, socially acceptable and economic option for the effective control of gambusia and carp in Australian waters • A strategy and process to initiate a long-term control program, involving State and Commonwealth agencies and the public.
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5A. Anticipated Outcomes • An improved understanding of the biology of pest species in the MDB that will form the basis of an integrated pest control program to reduce the impacts of introduced fish in the MDB and nationally • Community engagement in a coordinated program to control carp and gambusia
6A. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientists and other experts involved in the research and management of pest species using genetic control techniques, interest groups including animal welfare organisations etc.
Studies currently underway by the States and the Freshwater CRC are directly relevant to the planned program, particularly with regard to developing models for population dynamics and genetics, and impacts, which will be essential to predict the utility of control methods and develop effective release and monitoring strategies. This project builds on initiatives funded by MDB2000, as well as work being supported by the States, FRDC and the CRC.
Prior discussion (e.g. at the MDBC-sponsored workshop on carp control, Bendigo, 1996) emphasised the key role of the States in any pest fish control program based on genetic technologies, and their interest and ability to participate. The states have expertise and facilities for secure field trials, for monitoring pest populations and impacts, and for cost-effective rearing of carriers. The CSIRO provides complementary skills in genetic technologies and pest population dynamics. The effectiveness of genetic control techniques is greatly enhanced by selective removal of large carp in the initial stages of the program. Community-based programs of carp removal would provide a valuable contribution to long- term carp control when combined with genetic technologies.
7A. Estimated cost and duration Step 1 (already completed): 5 years, $4 million Step 2 (gambusia): 3 years, $5 million Step 2/3 (carp and gambusia combined): 7 years, $12 million Costings for the long-term eradication would be undertaken as part of the initial studies.
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PART 17B Investigation of biological control methods for a key plant pest, arrowhead Sagittaria
There are three species of arrowhead (Sagittaria spp.) present in Australia, Sagittaria sanfordii, S. montevidensis and S. graminea. S. graminea (referred to here as arrowhead) is the most invasive and widespread species, which has rapidly spread in the MDB along natural waterways, irrigation supply channels and drains where it causes disruption to the flow of water. It was first documented in Nine Mile Creek at Wunghnu as far back as 1961 and for many years was considered to be nothing more than another aquatic plant in the creek system. Heavy infestations of arrowhead have recently been recorded by DNRE Victoria along the Murray River.
Arrowhead appears to have become a major threat to natural ecosystems and the general riverine environment. It is now a serious problem in the irrigation areas of northern Victoria spreading via major rivers and their tributaries and major stakeholders and water distributors are very concerned about the rapid spread of this weed and its environment impacts. For example, arrowhead has been recorded spreading at an alarming rate in the last few years from upstream of the Ovens and Murray confluence to downstream of the Torrumbarry Weir. Infestations have been recorded in significant riverine lagoons and waterways, including the waterway of the Barmah-Millewa forest. It is believed the Murray River is a major seed bank for spread into the Goulburn and Ovens rivers. This demonstrates the need for a major co-operative research program to address specific management issues for arrowhead control and eradication in south eastern Australia’s most important river system. Issues such as the use of herbicides and environmental sensitivity to important plant communities, the potential of biological control and the integrated weed management in both natural areas and commercial irrigation channels need to be addressed quickly.
2B. Project Objectives • To review the potential for classical biological control for arrowhead (S. graminea) surveying existing insect/pathogen pests in Australia and specifically from its native range (south eastern USA). • To identify key priority areas within the MDB where these methods could be applied. • Review and commence research into targeted chemical and mechanical control methods for arrowhead and future integration with biocontrol in IWM solutions.
3B. Key Tasks • Review current IWM methodologies in Australia and overseas. • Identify key representatives in Australia and overseas who are experienced in management of Sagittaria species and biological control of aquatic weeds and liaise with them on current research and management solutions. • Conduct a major symposium and workshop into the management of arrowhead • Identify gaps and commence appropriate research into new techniques, including mechanical and chemical and integration of both. Tasks may include identifying key knowledge that will be required, developing a suitable technique, carrying out modelling to predict potential effectiveness and likely outcomes. • Publish best-bet management guidelines for arrowhead based on current knowledge.
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• Identify key priority areas within the MDB where potential methods should be applied and specifically local areas where eradication of arrowhead is achievable. • Review the potential for biological control of arrowhead within Australia and overseas. This should include an assessment of the successes and possible failures in the range of approaches, their potential benefits and costs and practicalities. • Identify any potential obstacles in trialing particular biological control techniques e.g. ethical and social concerns, environmental concerns etc. • Review each relevant promising technique in relation to impacts of implementation e.g. key aspects of the specific insect species within the MDB i.e. whether there is sufficient data on each species and their ecology, environmental considerations and possible methods of transmission • Plan long-term research project into promising biological control techniques for arrowhead addressing identification of key tasks, timeframes, resources and commitments. • Produce management strategy and communications plan for arrowhead • Conduct community awareness and education programs on the arrowhead management.
4B. Anticipated Products • A comprehensive review of existing IWM practices and techniques for arrowhead with clearly identified knowledge gaps and impediments to effective management • Best-bet management solutions for arrowhead based on existing knowledge and targeted at specific problem areas • A comprehensive review of the potential for biological control of arrowhead and recommendations for targeted organisms for the species native range. • A strategy to initiate a long-term research project to trial promising biological control techniques for reducing the impacts of arrowhead.
5B. Anticipated Outcomes • Improved and effective IWM of arrowhead in natural areas as well as commercial water supply areas • Reduce rate of spread of arrowhead and eradicate populations of the species in feasible localities. • Establishment of at least one biological control agent for arrowhead in the first 5 years. • Increased community and stakeholder involvement in the management of arrowhead
6B. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threat of pest species to communities and habitats has been identified as a priority management issue within the Riverine Environment Strategic Plan.
Although a major weed in the MDB, arrowhead is not of Weed of National Significance and is not eligible for funding under the National Weeds Program (NHT). This is a likely reason why it has not been selected as a model weed for targeted research in the new CRC for Australian Weed Management. Patronage and financial support from MDBC may prove crucial to build necessary research momentum required to achieve significant improvements in IWM of arrowhead.
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7B. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, scientists and other experts involved in the research and management of pest species using biological control techniques, interest groups etc. International linkages are also important to draw on the knowledge gained about particular methods of biological pest control.
Given the potentially controversial nature of some possible techniques, extensive consultation with all relevant stakeholders is required during all stages of the project.
Goulburn Murray Water (GMW) has commenced a small research project on the biology, ecology and control of arrowhead in commercial aquatic environments. This work has been funded by GMW, Murray Water, Goulburn Broken Catchment Management Authority, North Central CMA with support from DNRE Victoria. Funding of new arrowhead research would provide essential collaboration between these organisations and necessary research partners. It is likely that increased research activity would attract some in kind and financial support from the Weeds CRC. The proposed arrowhead research programs would improve its potential success by including TEG’s in the research phase and not just at implementation.
8B. Opportunities for end-user involvement End-users involve key government bodies across the MDB, land and water management authorities, scientists and other experts involved in the research and management of pest species using biological control techniques, interest groups, Landcare and community groups etc.
9B. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating the results of the project within the community • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users as a review document.
10B. Estimated cost and duration Short to medium term (1-2 years) = $150 000- $200 000 Costings for the long-term investigation would be undertaken as part of the initial scoping studies. Integrated weed management and biological control research may cost in the vicinity of $225 000/year for 5 years. (NB Research into biocontrol is anticipated to take up to 9 years to achieve all aspects of research and implementation)
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7.4.18 Research Project Brief 18: Assessment of the Effectiveness of Habitat Restoration as a Method for Controlling Biological Invasions
1. Key Management Issue(s) (as identified in the RESP) • R4a) Re-establishing populations and communities • R4b) Managing floodplain, wetland and riparian habitats • R4c) Managing instream and estuarine habitats • 4Rd) Managing threats to communities and habitats
2. Context, and how this addresses key management issue(s), strategies or policies Rivers within the MDB have experienced a range of degrading processes including river regulation, diversions and channelisation, vegetation clearance and removal of habitat components such as snags and reduction in habitat diversity, erosion and sedimentation, thermal and chemical pollution, introduction of pest plant and animal species etc. It is a common observation that invasive species are more likely to be successful in habitats modified or disturbed by human activities than undisturbed habitats, and that certain invasive species may also cope poorly under some natural conditions (Williamson 1996, Arthington et al. 1990).
Rehabilitation of riparian and aquatic habitats is now recognised as a necessary management action for many degraded areas, including many areas across the MDB. It is currently occurring on a range of levels and scales (e.g. resnagging, willow removal, restoration of natural flow regimes, revegetation of riparian zones, bank stabilisation etc) and is being implemented by numerous land and water management authorities, conservation and interest groups. River restoration is defined as aiming to protect and rehabilitate the physical and biotic processes of a river in a way that is conducive to the progression of ecosystems towards their natural state (Koehn et al. 1997). Our understanding of how effective river restoration activities are in restoring native aquatic and riparian communities is incomplete and many restoration projects do not place adequate emphasis on the goals or include monitoring components. River rehabilitation should include setting goals, strategies, implementing works and evaluating success (Ladson et al. 1999). One of the goals for river restoration is reducing the dominance of pest species in some rivers.
Habitat rehabilitation has been postulated as a potential form of pest control by making the environment more suitable for the proliferation and reproduction of self sustaining populations of native species on one hand, and reducing the suitability of conditions for pest species on the other (Harris 1997). This approach utilises the hypothesis that some pest species are symptoms of river degradation and that rehabilitating rivers to a more natural condition will reduce their competitive advantage. If we are to adopt this hypothesis then we need to evaluate the pest species to which it applies, and the mechanisms that lead to its successful invasion and persistence so that appropriate goals, strategies, works and success criteria can be established for any rehabilitation program. There are many factors which complicate hypotheses in relation to disturbance and establishment of pest species such as the type, frequency and intensity of the disturbances (e.g. pulses and presses).
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This project aims to identify potential ecological mechanisms and the vectors that lead to invasion by the pest species, those that have led to their persistence and proliferation, and those that could be used to contribute to the control and eradication of pest species. Once the ecological vectors and mechanisms for control have been identified, an evaluation of how river restoration activities can be used to initiate these processes will be identified (e.g. restoration of more natural flow regimes, revegetation of riparian zones, resnagging activities etc). This project will provide a better understanding of which components of restoration programs are most effective in restoring native populations and at the same time reducing pest populations and how changes to the environment may lead to changes in balance between populations of pest and native species.
3. Project Objectives • To assess the effectiveness of river and riparian rehabilitation programs as a method to control pest species. • To identify potential ecological mechanisms and the vectors that lead to invasion by pest species, their persistence and proliferation and those that could be used to contribute to the control and eradication of pest species. • To ensure that pest management principles are incorporated into all relevant rehabilitation programs within the MDB.
4. Key Tasks • Review key theories of pest species invasions identifying mechanisms which facilitate invasions. • Identify the features of river disturbance and current management that have created conditions that were suitable for invasion by, and persistence of pest species populations within the MDB. • Review the existing condition of flora and fauna communities within the MDB and determine the ecological characteristics that have led to invasion and persistence by pest species. • Based on these reviews identify knowledge gaps which limit our ability to manage and eradicate pest species. • Identify groups of pest species and more specifically particular invading species that could be favoured by disturbance. • Identify the ecological characteristics of native species that would lead to their recovery. • Identify criteria to determine the recovery potential (resilience) of damaged communities in relation to pest species. • Review existing literature to identify examples of pest species that have been controlled through river rehabilitation overseas, in Australia and in the MDB. • Review current and potential river and riparian rehabilitation programs within the MDB, and identify which programs already incorporate pest species principles and those which could potentially consider pest species management as an integral goal. • Develop and test hypotheses that address the mechanisms by which specific disturbances could have favoured the establishment and proliferation of populations of invading species. This should identify confounding factors which may limit the ability to test hypotheses. This task could include a modelling approach.
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• Determine how assessments of the effectiveness of rehabilitation should incorporate control of pest species. This could include monitoring programs to determine the status of populations of native and pest species before and after rehabilitation works are undertaken. • Develop appropriate pest management goals, strategies, works and success criteria for any rehabilitation program. • Develop targeted rehabilitation projects which incorporate pest species management as a key goal.
5. Anticipated Products • A comprehensive report identifying current features of disturbance within the MDB, causes of disturbance, current knowledge of features which benefit invaders and disadvantage native species. • A comprehensive review of rehabilitation programs which have incorporated pest management principles and their success. • A report documenting current and potential rehabilitation programs within the MDB which could incorporate pest management principles. • A guide to incorporating pest management principles within rehabilitation programs within the MDB, including goals, strategies and success criteria to effectively evaluate programs.
6. Anticipated Outcomes • A better understanding of the vectors and potential ecological mechanisms that lead to successful invasion and persistence of invasive species within the MDB and those that could be used to contribute to the control and eradication of pest species. • Pest management principles incorporated into all relevant rehabilitation programs within the MDB. • An improved recognition of end-users to the importance of pest control and its potential link to broader rehabilitation programs within the MDB.
7. The Commission’s need to fund this work (how will it meet our Strategic Objectives) Managing the threats of pest species to communities and habitats has been identified as a priority management issues within the Riverine Environment Strategic Plan.
8. Opportunities for linkage or collaboration Implementation of the project tasks will involve direct linkages and collaboration between key government bodies, land and water management authorities, scientific experts, interest groups (e.g. conservation groups, Landcare groups etc) involved in a range of rehabilitation programs across the MDB. International linkages will also be important to draw on the knowledge of rehabilitation programs overseas. Linkages should be developed with all relevant MDBC projects so that they incorporate pest management principles.
9. Opportunities for end-user involvement End-users involve key government bodies, land and water management authorities, scientific experts, interest groups (e.g. conservation groups, Landcare groups etc). they will be involved in all aspects of the project where direct liaison will be undertaken to determine the range of rehabilitation programs currently underway and planned within the MDB, whether and how pest management principles are incorporated into these programs etc. 204 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Project Briefs
10. Mechanisms for transfer and adoption • Liaison with MDBC education unit to assess appropriate methods for disseminating the results of the project to the community. • The steering committee will include appropriate representatives from end-users • The range of information concerning the project will be disseminated to end-users. This will include comprehensive reports of reviews, and a guide to incorporating pest management principles into relevant rehabilitation programs.
11. Estimated cost and duration Short Term = 1.5 years Cost = $150 000 If the project was to incorporate the testing of hypotheses, this may increase the costings.
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Lund, M. (1999b) Mosquitofish: Friend or Foe?. http://www.ecu.edu.au/chs/cem/research/research/exotic/ghfoe.html. Maciolek, J. A. (1984) Exotic fishes in Hawaii and other islands of Oceania. In: Distribution, Biology and Management of Exotic Fishes. (eds. Courtenay, W. R. and Stauffer, J. R.). The John Hopkins University Press, Baltimore. Pp. 131-161 Mack, R. N., Simberloff, D., Lonsdale, M., Evans, H., Clout, M and Bazzaz, F. (2000) Biotic Invasions: Causes, Epidemiology, Global Consequences and Control. Issues in Ecology 5:1-20. McAllister, D. E. and Crossman, E. J. (1973) A Guide to the Freshwater Sport Fishes of Canada. National Museums of Canada, Ottawa. McDowall, R. M. (1996) Family Poeciliidae: Livebearers. In: Freshwater Fishes of South Eastern Australia. (ed. McDowall, R. M.). Reed Books, Chatswood, NSW. McKay, R. J. (1984) Introductions of exotic fishes in Australia. In: Distribution, Biology and Management of Exotic Fishes. (ed. Courtenay, W. R. and Stauffer, J. R.). John Hopkins University Press, Baltimore.
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McKay, S., Clunie, P., Gillespie, G., Raadik, T., Saddlier, S., O'Brien, T., Ryan, T. and Aland, G. (2001) Predation by Gambusia holbrooki: A Review of the Literature. A report for New South Wales National Parks and Wildlife Service, pp.96. MDBC (2000) National Management Strategy for Carp Control 2000-2005. Carp Control Coordinating Group and the Murray-Darling Basin Commission. 20 pp. MDBC (2000) Riverine Environment Sub-program - Strategic Investigations and Education in the Murray- Darling Basin. A Three Year Rolling Plan 2000-01 to 2002-03. Murray-Darling Basin Commission, Canberra. MDBC (2001) Report on the Workshop for the Management of Tilapia in the Northern Murray-Darling Basin. Toowoomba, 2-3 April, 2001. Meffe, G. K. (1984) Effects of abiotic disturbance on coexistence of predator-prey fish species. Ecology 65: 1525-1534. Merrick, J. R. and Schmida, G. E. (1984) Australian Freshwater Fishes: Biology and Management. Griffin Press Limited, Adelaide. Merrick, J. R., and Lambert, C. N. (1991) The Yabby, Marron and Red Claw. Production and Marketing. J.R. Merrick Publications, Sydney. Migdalski, E.C. and Fichter, G.S. (1977) The Fresh and Salt Water Fishes of the World. Bay Books Pty Ltd, Sydney. Milton, D.A. and Arthington, A.H. (1983) Reproductive biology of Gambusia affinis holbrooki Baird and Girard, Xiphophorus helleri (Gunther) and X. maculatus (Heckel) (Pisces; Poeciliidae) in Queensland, Australia. Journal of Fish Biology 23: 23-41. Ministerial Council on Forestry, Fisheries and Aquaculture (Australia and New Zealand) (1999) National Policy for the Translocation of Live Aquatic Organisms: Issues, Principles and Guidelines for Implementation. Canberra, 31 pp. Munir, A. A. (1993) A taxonomic revision of the genus Phyla Lour. (Verbenaceae) in Australia. Journal of the Adelaide Botanic Gardens 15: 109-128. Murray-Darling Basin Commission & CRC for Freshwater Ecology (1999) Riverine Management and Rehabilitation Scoping Study. Report for the Riverine Issues Working Group. 104 pp. Myers, G. S. (1965) Gambusia, the fish destroyer. Australian Zoologist 13: 102. Napela T. F. & Schloesser D. W. (1993) Zebra Mussels. Biology, Impacts and Control. Boca Raton, Lewis Publishers. O'Donoghue, P. Beveridge, I., and Philips, P. (1990) Parasites and Ectocommensals of Yabbies and Marron in South Australia. Central Veterinary Laboratories, South Australian Department of Agriculture, Vetlab Report. Oxford Dictionary. Revised Eigth Edition. (ed.) D. Thomson. Clarendon Press. Pannetta, F. D., and Dodd, J. (1987) Bioclimatic prediction of the potential distribution of skeleton weed, Chondrilla juncea L. in Western Australia. Journal of the Australian Institute of Agricultural Science 53(1): 11-16. A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 213 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. References
Pannetta, F. D, and Mitchell, N. D. (1991) Homocline analysis and the prediction of weediness. Weed Research 31: 273-284. Pannetta, F. D., and Dodd, J. (1995) Chondrilla juncea L. In: The Biology of Australian Weeds. Volume 1. (eds. Groves, Shepherd and Richardson, RG and FG Richardson). Melbourne. Pidgeon, R. W. and Cairns, S. C. (1983) Decomposition and colonisation by invertebrates of native and exotic leaf material in a small stream in New England (Australia). Hydrobiologia 77: 113-127. Pimentel D. (2000) Environmental and economic costs of nonindigenous species in the United States. BioScience 50(1): 53-65. Pollard, D. A. (1974) The biology of landlocked form of the normally catadromous salmoniform fish Galaxias maculatus (Jenyns) VI. Effects of cestode and nematode parasites. Australian Journal of Marine and Freshwater Research 25: 105-120. Ponder W. F. (1988) Potamopyrgus antipodarum - A molluscan coloniser of Europe and Australia. Journal of Molluscan Studies 54: 271-285. Ponder W. F. (1994) Australian Freshwater Mollusca: conservation priorities and indicator species. Memoirs of the Australian Museum 36: 191-196. Ponder W. F. and Waterhouse J. H. (1997) A new genus and species of Lymnaeidae from the Lower Franklin River, South Western Tasmania, Australia. Journal of Molluscan Studies 63: 441-468. Pullan N. B., Climo F. M. & Mansfield C. B. (1972) Studies on the distribution and ecology of the family Lymnaeidae (Mollusca: Gastropoda) in New Zealand. Journal of the Royal Society of New Zealand 2: 393-405. Queensland Department of Primary Industries (2001) Control of Exotic Pest Fishes: An Operational Strategy for Queensland Freshwaters. 39 pp. Raadik, T. A. (1995) A Research Recovery Plan for the Barred Galaxias in South-eastern Australia. Department of Conservation and Natural Resources. Victoria. Read, M. G. and Barmuta, L. A. (1999) Comparison of benthic communities adjacent to riparian native eucalypt and introduced willow vegetation. Freshwater Biology 42: 359-374. Ribi G. (1986) Within lake dispersal of the prosobranch snails, Viviparus ater and Potamopyrgus jenkins. Oecologia 69: 60-63. Ricciardi A., Whoriskey F. G. & Rasmussen J. B. (1996) Impact of the Dreissena invasion on native unionid bivalves in the upper St Lawrence River. Canadian Journal of Fisheries and Aquatic Sciences 53(6): 1434-1444. Richardson, D.M., Pysek, P., Rejmanek, M., Barbour, M. G., Pannetta, F.D. and West, C. J. (2000) Naturalisation and Invasion of Alien Plants: Concepts and Definitions. Diversity and Distribution 6: 93- 107. Rivas, L. R. (1963) Sub-genera and species groups in the poeciliid fish genus Gambusia Poey. Copeia: 331- 47.
214 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. References
Roberts, J. and Ebner, B. (1997) An overview of carp, Cyprinus carpio in Australia: Final Report on National Resource Management Strategy Project R5058. An advisory document to the Murray-Darling Basin Commission. Roberts, J. and Tilzey, R. (1997) Controlling Carp: Exploring the Options for Australia. Proceedings of a workshop 22-24 October 1996, Albury. CSIRO, Murray-Darling Basin Commission. Roberts, J. (in press) Species-level knowledge of riverine and riparian plants: A constraint for determining flow requirements in the future. Australian Journal of Water Resources, IEAust. 2002;5(1):21-32. Rosecchi, E., Thomas, F. and Crivelli, A.J. (2001) Can life-history traits predict the fate of introduced species? A case study on two cyprinid fish in southern France. Freshwater Biology 46: 845-853. Roughley, T.C. (1971) Fish and Fisheries of Australia. Angus and Robertson. Sydney. Saaty, T. (1995) Decision-making for Leaders: The Analytical Hierarchy Process for Decisions in a Complex World. RWS Publications, Pittsburgh. Sainty, G. R. and Jacobs, S. W .L. (1994) Water Plants in Australia: A Field Guide. Sainty & Associates, Potts Point, Sydney. Schreiber E. S. G., Glaister A., Quinn G. P. & Lake P. S. (1998) Life history and population dynamics of the exotic snail Potamopyrgus antipodarum (Prosobranchia: Hydrobiidae) in Lake Purrumbete, Victoria, Australia. Marine and Freshwater Research 49: 73-78. Schulze, D.J. and Walker, K.F. (1997) Riparian eucalypts and willows and their significance for aquatic invertebrates in the River Murray, South Australia. Regulated Rivers: Research and Management 13: 557-577. Serventy, V. and Raymond, R. (1980) Lakes and Rivers of Australia. Summit Books, Syndey: p. 160. Shearer, K. D. and Mulley, J. C. (1978) The introduction and distribution of the carp Cyprinus carpio Linnaeus, in Australia. Australian Journal of Marine and Freshwater Research 29: 551-564. Shipway, B. (1951) The natural history of the marron and other freshwater crayfishes of south western Australia. Western Australian Naturalist 3: 7-12, 27-34. Shirley, M. J. (1991) The Ecology and Distribution of Galaxias fuscus Mack in the Goulburn River System, Victoria. B.Sc. Honours Thesis, Zoology Department, University of Melbourne. 40pp. Strayer D. L., Caraco N. F., Cole J. J., Findlay S. & Pace M. L. (1999) Transformation of freshwater ecosystems by bivalves: a case study of zebra mussels in the Hudson River. Bioscience 49: 19-27. Stuart, I. and Jones, M. (2001) Targeting spawning habitats to reduce carp populations. Proceedings of the 12th Australasian Vertebrate Pest Species Conference. Natural Resources and Environment. 178-193. Swanson, C., Cech, J. J. J., and Piedrahita, R. H. (1996) Mosquitofish: Biology, Culture, and Use in Mosquito Control. Mosquito and Vector Control Association of California; The University of California Mosquito Research Program., California, U.S.A. Swee, U. B. and McCrimmon, H. R. (1966) Reproductive biology of the carp, Cyprinus carpio L., in Lake St. Lawrence, Ontario. Transactions of the American Fisheries Society 95: 372-380.
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Thompson, M. B. (1983) Populations of the Murray River tortoise, the effects of egg predation by the red fox. Australian Wildlife Research 10:363-371. Tilzey, R. D. J. (1976) Observations on interactions between indigenous Galaxiidae and introduced Salmonidae in the Lake Eucumbene catchment, NSW. Australian Journal of Marine and Freshwater Research 27: 551-564. Tisdell, C. A. (1990) Economic impact of biological control of weeds and insects. In: Critical Issues in Biological Control. (eds. Mackauer, M., Ehler, L. E. and Roland, J.). Intercept, Andover, UK. Townsend, C.R. and Winterbourn, M.J. (1992) Assessment of the environmental risk posed by an exotic fish: the proposed introduction of channel catfish (Ictalurus punctatus) to New Zealand. Conservation Biology 6(2): 273-281. van Ramshorst, J. D. (1991) The Complete Aquarium Encyclopedia of Tropical Freshwater Fish. The Promotional Reprint Company Limited. Leicester, UK. Cited in Clarke, G.M., Grosse, S., Metthews, M., Catling, P.C., Baker, B., Hewitt, C.L., Crowther, D., Saddlier, S.R. State of the Environment Indicators for Exotic Environmental Pest Species. Environment Australia. Varley, M. E. (1967) British Freshwater Fishes. Fishing News Limited, London. Villarreal, H. and Hutchings, R. W. (1986) Presence of ciliate colonies on the exoskeleton of the freshwater crayfish Cherax tenuimanus (Smith) (Decapoda : Parastacidae). Aquaculture 58: 309-12 Wager, R. and Jackson, P. (1993) The Action Plan for Australian Freshwater Fishes. Australian Nature Conservation Agency, Brisbane, QLD: p. 122. Weatherley, A. H. (1967) Australian Inland Waters and their Fauna. Australian National University Press. Canberra. Whittington, R.J. and Cullis, B. (1988) The susceptibility of Salmonid fish to an atypical strain of Aeromonas salmonicida that infects goldfish, Carassius auratus (L.), in Australia. Journal of Fish Diseases 11: 461-470 Williamson, M. (1996) Biological Invasions. Chapman and Hall, London. Williamson, M. H. and Fitter, A. (1996) The characters of successful invaders. Biological Conservation 78:163-170. Wilson, F. (1960) A Review of the Biological Control of Insects and Weeds in Australia and Australian New Guinea. Commonwealth Agricultural Bureaux, Bucks, England.: p. 102. Winterbourn M. J. (1970) Population studies on the New Zealand freshwater gastropod, Potamopyrgus antipodarum (Gray). Proceedings of the Malacological Society of London 39: 139-149. Wooten, M. C., Scribner, K. T., and Smith, M. H. (1988) Genetic variability and systematics of Gambusia in the South eastern United States. Copeia 2: 283-289 Zaranko D. T., Farara D. G. & Thompson F. G. (1997) Another exotic mollusc in the Laurentian Great Lakes: the New Zealand native Potamopyrgus antipodarum (Gray 1843) (Gastropoda, Hydrobiidae).
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9. PERSONAL COMMUNICATIONS Arthington, A. Griffith University, Queensland Brooks, S. Queensland Fisheries Service Craig, S. CSIRO, Tasmania Georges, A. University of Canberra Growns, I. NSW Fisheries Henderson, R. Waterwatch, Northern Territory Johnson, I. Queensland Museum Knight, J. NSW Fisheries Lucy, M. Department of Primary Industries, Queensland Mawbey, B. Inland Fisheries Service, Tasmania Moffatt, D., Queensland Department of Natural Resources Raadik, T. Department of Natural Resources and Environment, Melbourne Robley, A. Department of Natural Resources and Environment, Melbourne Thresher, R., CSIRO, Tasmania
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Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Acknowledgements
10. ACKNOWLEDGEMENTS This scoping study was commissioned by the Murray-Darling Basin Commission and we thank Lance Lloyd for his advice and guidance in coordinating the study. Patrick Piggott, Nigel Ainsworth and Jack Craw of the Keith Turnbull Institute, provided assistance in the developments of Project Briefs 1, 3, 5, 6, 8, 10 and 11. We are grateful to Ron Thresher and Peter Craig, CSIRO Tasmania for assistance in the development of Project Brief 17 concerning biological control technologies. We also wish to thank all those who provided valuable responses to our questionnaires.
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11. APPENDICES
APPENDIX 1: Fauna Questionnaire
Objectives of the questionnaire process • To familiarise us with your management and/or research experience concerning the impact of aquatic pest fauna species on freshwater systems. • To identify current and potential aquatic pest fauna species within the Murray Darling Basin (MDB). • To determine whether existing educational information concerning aquatic pest fauna species are adequate. • To develop draft project outlines to address identified knowledge gaps and research needs.
Questions
Background 1. Please check your contact details and indicate your availability for a follow-up interview (if required).
Corrections Name «Title»«First»«Last» …………………………………………… … «Location» Address ………………………………………… «Street» ………………………………………… ………………………………………… «City» ………………. «State» «Postcode»
Phone «Phone» ………………………………………… ……
e-mail «Email» ………………………………………… ……
Available for a follow-up phone interview: ❏ YES ❏ NO
2. What is your involvement in the issue of pest species? Please tick the appropriate boxes. ❏ Research ❏ Community ❏ Management ❏ Regional ❏ Policy ❏ State ❏ National
220 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices ❏ other………………………………………………………………
3. Please provide some details on how you have been involved in activities relevant to policy development, management of, and/or research into, the effect of pest species on freshwater environments? ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. …………………………………………………………………………………………………………..
4. This questionnaire is being circulated to the people listed in Table 1. Can you suggest any additional people who you consider should have been included in this list? (Space is provided for your response at the end of the table). Table - Circulation List for Questionnaire was inserted here (see Table 6 in Section 4)
Additional people with relevant experience: ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. …………………………………………………………………………………………………………..
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 221 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices Identification of knowledge gaps 5. Table 2 summarises the principal current and potential aquatic pest fish species within the MDB5. We seek your opinions on the significance of the threat that each species may pose to the aquatic environment (and its associated flora and fauna). Please provide comments as to your reasons behind rankings (e.g. ease of spread, reproductive capacity, evidence of environmental degradation, economic impacts etc.). We recognise you may not be familiar with all species and you may omit any species you do not wish to comment on.
Instructions a) Please rank the significance of current and potential pest species from 1 (most important) to 13. b) Please provide any comments to explain your ranking. c) Please add any other fish species you believe should be on this list (NB: Ornamental fish are addressed later in this questionnaire).
Table 2 - Current and Potential Aquatic Pest Fish Species within the MDB Species Ranking Comments Brown Trout Salmo trutta Rainbow Trout Oncorhynchus mykiss Atlantic Salmon Salmo salar Brook Trout Salvelinus fontinalis Redfin Perca fluviatilis Carp Cyrinus carpio Goldfish Carrasius auratus Guppy Poecilia reticulata Gambusia Gambusia hobrooki Tilapia Oreochromis mossambicus Tench Tinca tinca Roach Rutilis rutilis Weatherloach Misgurnus anguillicaudatus Other • •
5 This list has been obtained from reviews of introduced species e.g. Arthington and Blűhdorn (1995) Improved management of exotic aquatic fauna: Research and development for Australian rivers. LWRRDC Occasional Paper 04/95, and Arthington and McKenzie (1997) review of impacts of displaced/introduced fauna associated with inland waters. State of the Environment Technical Paper Series (Inland Waters). 222 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices Table 3 provides a list of broad management and research options for aquatic pest fish species within the MDB. The table includes columns for each of the 13 current and potential species identified above. Instructions
1. Please tick boxes to indicate which options you believe are important and which would be a suitable basis for projects.
2. Please add any other management and/or research priorities in the space provided at the end of this table.
Table 3 - Management and Research Options for Aquatic Pest Fish Species Issue Brown Rainbow Atlantic Brook Redfin Carp Goldfish Guppy Gambusia Tilapia Tench Roach Weatherloach Species Trout Trout Salmon Trout Monitoring/Research • Population status and distribution • Identification of appropriate survey techniques • Documentation of historical information (e.g. introduction) • Documentation of trend (e.g. rate of spread) • General biology (e.g. growth, longevity, maturity) • Habitat preferences/requirements • Physiological tolerances (e.g. salinity, temperature) • Reproduction (e.g. spawning cues, breeding biology) • Diet • Movement (e.g. migratory patterns) • Behaviour (e.g. species interactions) Impacts : • Aquatic flora (e.g. macrophytes) • Aquatic fauna (e.g. fish, invertebrates) • Interactions with native species (e.g. competition/predations) • Change in biodiversity • Water quality (e.g. turbidity, algal blooms) • Ecological processes (e.g. nutrient cycling) A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 223 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices Table 3 - Management and Research Options for Aquatic Pest Fish Species (cont') Issue Brown Rainbow Atlantic Brook Redfin Carp Goldfish Guppy Gambusia Tilapia Tench Roach Weatherloach Species Trout Trout Salmon Trout • Riparian environment (e.g. bank erosion) • Diseases, Viruses • Genetics • Economy (e.g. decline in commercial, recreational fishing opportunities) • Social (e.g. aesthetics) Methods of Control/Management • Habitat restoration (e.g. revegetation, resnagging) • Prevention of introduction (e.g. barriers) • Eradication techniques (e.g. poisoning) • Reduction in abundance (e.g. harvesting) • Environmental manipulation (e.g. flow manipulation) • Biological control (e.g. introduction of viruses, immunocontraception) • Biomanipulation (e.g. manipulating interrelationships between species and environment for ecological balance) • Importation/Introduction controls • Improved consultation (e.g. identification of appropriate experts, interest groups) • Coordination of management (e.g. States, groups) • Strategies/Management processes • Education • Reintroduction of native species • Data collection and interpretation Other •
224 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices Ornamental Fish Species There is an extensive review of the quarantine risk potentially associated with the importation of ornamental finfish into Australia (Arthington et al. 1999). This document provides lists of the large number of ornamental finfish species which are recorded and established in Australian waters as well as potential introductions.
6. Are there any species of ornamental fish which you are particularly concerned may be released and/or become established in the MDB? Please specify. ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… Vertebrate Pest Species 7. Are you aware of any other current or potential aquatic vertebrate pest species? Please specify? ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… Aquatic Invertebrate Pest Species A extensive review of introduced freshwater invertebrates within the MDB has not been undertaken, however a small number have been identified in reviews such as Arthington and Blűhdorn (1995).
8. Are you aware of any current or potential aquatic or riparian invertebrate pest species? Please specify? ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… Translocated Native Species The definition of a 'pest' may include native species which have been released into areas outside of their natural ranges for purposes such as recreational fishing.
9. Are there any native species which you consider may be, or may potentially be, pest species where they occur outside their natural range (e.g. golden perch Macquaria ambigua, marron Cherax tenuimanus)
……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… Research Priorities Based on your comments in Table 3 and questions 7 to 9, do you wish to provide further information concerning suitable research projects which are needed to address the issue of aquatic pest fauna species? If so, please specify below.
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10. Please elaborate on any research priorities that you have identified as important for aquatic pest species. (Optional)
1. Project Outline/Objective: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Type of project: ❏ Desktop ❏ Laboratory trials ❏ Field monitoring ❏ In-situ trials ❏ Modelling ❏ Other ……………………………………………………………………..
Resources required: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Duration: ………………………………………………………………………………………………………
2. Project Outline/Objective: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Type of project: ❏ Desktop ❏ Laboratory trials ❏ Field monitoring ❏ In-situ trials ❏ Modelling ❏ Other ……………………………………………………………………..
Resources required: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Duration: 226 A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices
………………………………………………………………………………………………………
3. Project Outline/Objective: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Type of project: ❏ Desktop ❏ Laboratory trials ❏ Field monitoring ❏ In-situ trials ❏ Modelling ❏ Other ……………………………………………………………………..
Resources required: ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………………
Duration: ………………………………………………………………………………………………………
Research and Management Approaches 11. Can you provide examples of research and/or management approaches that you consider to be particularly useful in addressing the impacts and/or management of aquatic pest species? (For example, a field based approach as opposed to a laboratory based approach or community implementation rather than a management initiative). Please indicate target species if appropriate. …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………………
12. Can you provide examples of research and/or management approaches that are not effective in addressing the issue of aquatic pest species and their management? Please indicate target species if appropriate. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… Education
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13. Are you aware of any educational material for school students, community groups and the broader community concerning aquatic pest species, their impacts on the environment and their management? If so, please provide details on material and comment on their effectiveness as educational tools. …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………………
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APPENDIX 2: Weed Risk Assessment
Table A1.1 Aquatic Weed Risk Assessment for the Murray-Darling Basin Definition and Intensity Ratings of Invasiveness Criteria CRITERIA RANK INTENSITY RANKING WEIGHT Versatility: Range of environmental tolerance
Temperature H Frost / Ice tolerance 1 tolerance MH Growth checked by winter temperatures 0.667 ML Dies off over winter to overwintering structure 0.333 L Annual weed 0 Salt tolerance H Salt tolerance >50% sea water include brackish, estuarine 1 L Not salt tolerant 0 Range of H Tolerant of wide range - Able to grow in or both in and on water 1 habitat through to dry land M Intermediate - Can grow from wetland and spread over water or wide 0.5 depth range L Narrow range tolerance - Under water grows only in shallows (<2 m) 0 or form narrow fringe over water Range of H Wide range of substrates or nutrient states 1 substrates L Restricted to one substrate type or nutrient status (eg. only in acid or 0 alkaline waters) Water clarity H Not constrained by clarity (ie. grows on top of water or quickly extends 1 to surface) L Constrained by water clarity 0 Competitive ability: Between and within life forms
Competitive H Displaces greater than 5 other introduced species of the same life form 1 ability (within life MH Displaces between 4 and 5 other introduced species of the same life 0.667 form) form ML Displaces between 1, 2 or 3 other introduced species of the same life 0.333 form L Doesn't displace any other introduced species of the same life form 0 (may displace natives) Competitive H Displaces other introduced species of different life forms 1 ability (between life L No impact on other introduced species of different life forms 0 forms) Propagule dispersal: Vectors for dispersal, natural, accidental, inter and intra catchment
Birds, wind H Readily dispersed by waterfowl or wind to new waterbodies or 1 spread catchments outside or to M Rarely dispersed by waterfowl or wind to new waterbodies or 0.5 new catchments catchment L Never naturally dispersed to new waterbodies or catchments 0
Accidental H Dispersed by drainage machinery, recreational craft and fishing nets 1 human
A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 229 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices spread M Dispersed by 1 or 2 of these (machinery, recreational craft or fishing 0.5 nets) L No dispersed by accidental human spread 0 Deliberate H Perceived as having ornamental value (spread deliberately by humans) 1 human spread L Not perceived as having ornamental value (not spread deliberately by 0 (aquaculture) humans) Dispersal H Able to rapidly (within 5 years) colonise all available habitat within 1 upstream or waterbody or catchment downstream M Intermediate (within 5 - 25 years) colonise all available habitat within 0.5 within waterbody or catchment catchment L Slow spread (greater than 25 years) 0 Seeding ability: Production and longevity
Quantity of H Greater than 1000 viable seeds per plant 1 seeds (sexual MH Between 100 and 1000 viable seeds per plant 0.667 reproduction) per plant ML Between 1 and 100 viable seeds per plant 0.333 L No seed production (asexual reproduction) 0 Viability or H Long lived seed of high viability (>25% survive greater than 10 years) 1 persistance of seeds M Seeds produced but not persistant (generally less than 10 years though some <25% survive greater than 10 years 0.5 L No seed set (asexual reproduction) 0 Cloning ability Methods of H Spread by fragmentation 1 vegetative spread MH Far reaching rhizomes/stolons >10 m 0.75 M Rhizomes or stolons <10 m 0.5 ML Clump forming (inter or extra vaginal spread) 0.25 L No clonal spread (eg. annual or produces finite number of shoots) 0 Maturation rate How long to H No requirement for maturity (eg. readily fragments) 1 produce propagules M Maturity within 1 growing season (usually 1 year) 0.5 (including fragmentation) L Maturity greater than 1 year 0
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Table A1.2 Definition and Intensity Ratings of Impact Criteria CRITERIA RANK INTENSITY RANKING Degree of obstruction: Social, economic and aesthetic
Recreational H Major - Unable to use waterbody for recreation (fishing, swimming, skiing, boating) obstruction M Limited use of waterbody L Unlimited use of waterbody for recreation Access to H Unable to access water - physical barrier to water waterbody M Impeded access - able to reach water with degree of difficulty L Unimpeded or minor nuisance in accessing waterbody Power H Requires continual management to ensure hydroelectric production (cleaning generation screens, etc) M Periodic maintenance required to ensure production of hydro power L No impedance of hydro power production Irrigation or H Requires continual management to maintain irrigation or flood control requirement flood control M Seasonal or intermittent management required L Little or no management required to maintain irrigation or flood control Aesthetic H Visual and olfactory problem M Visual or olfactory problem L Neither Damage to natural ecosystems Reduce H Full monoculture displacing all other species biodiversity MH Displaces at least 75% of other species M Displaces between 25-75% of other species ML Co-exist with native vegetation - but impacts on other biota (fish, invertebrates or specific grazers, etc) L Co-exist with native vegetation - no impact on biota Decrease water H De-oxygenation and nutrient enrichment sometimes producing algal blooms quality L No change to water quality (oxygen and nutrient status) Impact on H Promotes both flooding and erosion of sediment physical Processes M Increases either flooding regimes or erosion of sediment L No increase in either floods or sediment erosion Resistance to management
Ease of H Extremely difficulty in carrying out control (eg. to physically access plant - eg. deeply submerged implementation plant or dense swards of marginal spp.) M Impedance of access to whole of infestation L No or minor restriction in accessing plants Recognition of H Plant difficult to detect (eg. submerged) problem spread L Plant highly visible or prominent at certain time (eg. distinctive flowers or emergent) Scope of H No effective control mechanism available available A report to MDBC (R2006) - Freshwater Ecology & KTRI, DNRE & Dr. Jane Roberts 231 Clunie et al. (2002) A Risk Assessment of the Impacts of Pest Species in the Riverine Environment in the MDB. Appendices control methods M At least 1 mechanism available - mechanical, chemical or biological L At least 2 effective control mechanisms available (eg. mechanical and chemical) Acceptability of H Control methods may not be acceptable by local community (eg. herbicides in town control water or grass methods carp) L No perception problems by communities Effectiveness of H No effective control - weed continues to expand control M Partial control (manage it but not eradicate it) L Control methods may lead to eradication Duration of H Uncontrolled - control methods either unavailable or continual application is control required M Control required greater than 2 years per infestation L Single application required per year controls weed Range of habitat: Grows in flowing, still or wetland habitats
Lentic: flowing H Major weed water MH Minor weed ML Present but not weedy L Absent Lotic: Ponds, H Major weed reservoirs and lakes MH Minor weed ML Present but not weedy L Absent Wetlands: H Major weed Temporarily flooded or MH Minor weed waterlogged soil ML Present but not weedy L Absent Other undesirable traits Human health H Strong likelihood that weed would increase chance of at least 2 of the following: drownings (stock or impairment humans), toxic effects, physical damage (eg. cuts, etc), mosquito breeding habitat M Medium likelihood that weed would increase chance of at least 1 of the following: drownings (stock or humans), toxic effects, physical damage (eg. cuts, etc), mosquito breeding habitat L No impact on human health Weed of H Weed of terrestrial agriculture terrestrial agriculture L Not a weed of terrestrial agriculture
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APPENDIX 3: Pest Plant Questionnaire: Questions and Answers Stakeholder consultation was done using an e-mailed questionnaire, supplemented by phone calls to encourage responses. Stakeholder was interpreted broadly to mean those with an interest in and knowledge of aquatic and riparian pest plants. The original e-mail letter plus questionnaire was sent to 120 e-mail addresses, compiled from two established lists for relevant interests and professions (Members Directory for Australian Society for Limnology, Weed Navigator) and personal contacts of Jane Roberts and David McLaren.
These listings proved not to be up to date and about 50 addresses proved unusable (ie bounced to sender). Replacement addresses were located for some, and additional names solicited. Some recipients forwarded the questionnaire to other persons. Because of this, the exact number of people receiving the questionnaire is unknown, but is assumed to be between 70 and 100.
There were 6 topics in the survey: [1] Respondents characteristics [2] Identifying current pests and threats: species and ecological attributes [3] Temporal changes [4] Impediments and challenges [5] Research priorities [6] Information products and needs These are described below giving the purpose, questions and findings.
Prompt List: As a prompt for the second topic, Identifying current pests and threats (Questions 6 and 7), a list of 124 plant species was provided. Originally this was intended as a list of non-native nuisance plants naturalised in aquatic and riparian habitats from major climatic zones (such as cool temperate, warm temperate, sub-tropical) across the Basin.
This list was developed de novo, there being no readily available look-up list of non-native (or native) aquatic and riparian plant species. Sources used for preparing this list were three Australian publications: Sainty and Jacobs (1994), Aston (1973), Carr et al. (1992). Threats were compiled from Web material, especially WONS and a search was done of volumes 12 to 20 inclusive of the scientific journal Wetlands (1992 to 2000). The list of species was extended and revised based on suggestions made by John Hoskin, Tom Anderson, Charles Ellway, Geoff Sainty and David McLaren. These suggestions resulted in the inclusion of several species not yet naturalised in the Murray-Darling Basin or not yet in Australia (eg Tamarix ramosissima, Myriophyllum spicatum) and one species that is native (eg Phragmites australis). Incorporating these suggestions thus shifted the focus of the prompt list to become slightly broader and more pragmatic, a perspective that was noted by a few respondents.
Including potential and well as actual pest plants could result in an exceptionally long species list. For pragmatic reasons, the size of the list was trimmed to two pages, a total of 124 species.
The prompt list had some idiosyncracies:
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• Noogorra burr Xanthium occidentale was included but not Bathurst burr Xanthium spinosum which was accidentally deleted. • Typha latifolia, the introduced species of cattail or bulrush, and may have been confused with the two Australian species T. domingensis and T. orientalis: however, it was not rated highly (Q6) or as a serious or threatening weed (Q7), so any such confusion does not alter general findings. • Willows Salix spp. had a mixed presentation, with three species and one ‘all-the-others’ taxon.
[1] Respondents characteristics
QUESTIONS 1 – 5: ANSWERS Respondents profile: The number of respondents was 45. Some respondents answered the species-specific questions for more than one area, thus the number of geographic areas covered was actually 50 for species- related questions.
Most of the 45 respondents had a professional interest in weeds, nuisance or pest plants, and nearly all had some experience in aquatic and and/or riparian species. This professional interest was mainly in management, or in research or in management and research (17, 11 or 12 respondents) as opposed to policy, or simply hobby interest. This professional interest was mostly at the regional level, rather than state or national (20 versus 6 and 2). An extension role was strongly indicated, with 11 respondents involved in some kind of community work. Researchers and academics, consultants, community groups and landholders are under-represented.
Bio-region: The distribution of the 50 responses showed a strong jurisdiction and bio-geographic bias. Most responses referred to NSW (26) and Victoria (11) or some combination of these (2). The response rate for South Australia and for the ACT was very low (1 only, each) thereby precluding any state-based analysis. The 50 responses were distributed unevenly across the bio-regions (IBRA Version 5), with a strong bias towards lowland bio-regions in the centre of the Murray-Darling Basin, and very few for Tableland and upland areas. Only rarely was a respondent’s geographic area constrained to just one bio-region, and it was more common to be be restricted to one drainage division. Usually a geographic area was spread across 2-4 bio-regions and sometimes across 2-3 catchments.
Five bio-regions were quite well-represented in the replies: RIV Riverina (17 respondents), SEH South East Highlands (13), NSS New South Wales Southern Slopes (15), DRP Darling Riverine Plains (10) and BBS Brigalow Belt South (12). These five are used to explore north and south contrast witin the Basin such as: • Northern parts v southern lowland-slopes areas of MDB (with northern being DRP and BBS, and southern being RIV and NSS).
Bio-regions that were poorly represented were: AA Australian Alps (1 respondent), VM Victorian Midlands (3), MDD Murray-Darling Depression (4), NAN Nandewar (3), NET New England Tablelands (2) and CP Cobar Peneplain (4). Upland and cooler climate areas were under-represented in this survey, and the semi-arid Mulga bio-region was intermediate (6 respondents).
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Habitats: Coverage across the two habitats, aquatic and riparian, was fairly even (34 and 29 each) and relatively few replies related exclusively to either one or these habitats (12). Artificial or constructed systems, usually irrigation areas, were also represented but in a minor way (8 replies).
[2] identifying current pests and threats: species and ecological attributes
QUESTION 6: Please indicate which species / taxa in Table 1 you consider to be a pest in aquatic and riverine habitats. ANSWERS Some respondents provided quite long lists of unwanted non-native species, suggesting that most non-native species are considered a pest, regardless of functional impact; others had particular targets in mind so nominated just one or two species.
Species receiving a high score are those recognised by a number of respondents as being a pest. A high score thus indicates a pest plant that is common or is widely distributed across the Basin. Although a total of 106 non-native species were ticked from the prepared list of 124, another 70+ species (some species identities are ambiguous) were added by respondents.
The highest score received by any species was 31 for Salix babylonica (the maximum possible was 50). Twentythree species scored 10 or more meaning these were considered pest species in at least 20% of the geographic areas surveyed (see below). One of these was Xanthium spinosum. This was not on the original list but was added by at least 20% of respondents. Weeping Willow Salix babylonica; Blackberry Rubus fructicosus, Noogorra burr Xanthium occidentale; African boxthorn Lycium ferocissimum; other willows Salix spp; lippia Phyla canescens; Curled Dock Rumex crispus; Spear thistle Cirsium vulgare; Umbrella sedge Cyperus eragrostis; Crack willow Salix fragilis; Variegated thistle Silybum marianum; ryegrasses Lolium spp; Sweet briar Rosa rubiginosa; Dodder Cuscuta campestris; St Johns Wort Hypericum perforatum; clovers Trifolium spp.; privets Ligustrum spp.; poplars Populus spp.
Notable features of this list of the top 23 widely distributed and frequently recognised pest species are: • The range of growth forms represented, with trees, shrubs, rushes & sedges, grasses, perennial and annual herbs, and climbers. • The growth forms with the most species are shrubs and annual herbs. Both these growth-forms are dominated by species that are predominantly terrestrial hence these when these species become invasive into the riparian zone, they are facultative riparian species rather than flood-dependent species (ie the riparian zone provides a favourable habitat within the context of the Basin). • The number of aquatic macrophytes and obligate riparian zone species in this top list is very few, being restricted to umbrella sedge Cyperus eragrostis and various willows Salix spp.. • Lippia Phyla canescens although typical of floodplains is drought tolerant and is not flood dependent, and may be favoured by both grazing and altered flow regime. • Several species in this list are increasers under grazing pressure, being not-palatable (eg thorns, prickles), thicket-forming, or animal dispersed (burr species).
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Table A2.1: The 23 species / taxa cited as a pest in 50 replies FORM and Family Genus Species Common Name TREES Salicaceae Populus spp Poplars Salix babylonica Weeping willow Salix fragilis Crack willow Salix spp. Other willows and hybrids SHRUBS Oleaceae Ligustrum spp Privets Solanaceae Lycium ferocissimum African boxthorn Rosaceae Rosa rubiginosa Sweet briar Rubus fructicosus Blackberry RUSHES & SEDGES Cyperaceae Cyperus eragrostis Umbrella sedge Juncaceae Junucus articulatus Jointed rush GRASSES Poaceae Lolium spp Ryegrasses Echinochloa crus-galli Barnyard grass HERBS – perennial Verbenaceae Phyla canescens Lippia Faboideae Trifolium spp. Clovers
HERBS – annual Asteraceae Cirsium vulgare Spear thistle Hypochaeris radicata Annual Flatweed Silybum marianum Variegated thistle Xanthium occidentale Noogorra burr Xanthium spinosum Bathurst burr Clusiaceae Hypericum perforatum St John’s wort Polygonaceae Rumex crispus Curled dock CLIMBERS Asparagaceae Myrsiphyllum asparagoides Bridal creeper Convolvulaceae Cuscuta campestris Dodder
Geographic variations in MDB: The list of 23 most frequently mentioned species (Table A2.2) is biased towards those that are widespread across the Basin. It is not sensitive to species that are locally or regionally important. Interpretation of geographic differences is thus limited to comparisons of relative importance of these widespread species in well-represented bio-regions, ie northern v southern lowland areas. Despite the relatively coarse sampling, the data for the 23 species shows clearly that ‘importance’ is not uniform across the Basin.
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African box thorn Lycium ferocissimum; lippia Phyla canescens Species relatively more important as a pest in southern than northern slopes & lowland bio-regions are: Umbrella sedge Cyperus eragrostis; Jointed rush Juncus articulatus; Sweet briar Rosa rubiginosa
Table A2.2: Geographic variations in significance of 23 pest species in the Murray-Darling Basin. Data are percentage frequency of that species being cited as a pest for each bio-region, with number of respondents per bio-region at top of column. Pest species are taken from the list in Table A2.1. NC means not calculated. Genus Species RIV SHE NSW DRP BSS (n=17) (n=13) NSS (n=10) (n=12) (n=10) TREES Populus spp 17 31 20 20 17 Salix babylonica 59 69 67 70 67 All Salix spp. 71 92 80 70 67 SHRUBS Ligustrum spp NC NC NC NC NC Lycium ferocissimum 18 23 40 60 67 Rosa rubiginosa 29 31 47 20 17 Rubus fructicosus 59 85 73 50 42 RUSHES & SEDGES Cyperus eragrostis 41 46 47 10 17 Junucus articulatus 35 31 40 10 8 GRASSES Lolium spp NC NC NC NC NC Echinochloa crus-galli NC NC NC NC NC HERBS - perennial Phyla canescens 47 15 40 70 58 Trifolium spp. NC NC NC NC NC HERBS - annual Cirsium vulgare NC NC NC NC NC Hypochaeris radicata NC NC NC NC NC Silybum marianum NC NC NC NC NC Xanthium occidentale 71 31 67 70 75 Xanthium spinosum NC NC NC NC NC Hypericum perforatum NC NC NC NC NC Rumex crispus NC NC NC NC NC CLIMBERS Myrsiphyllum 23 23 33 10 8 asparagoides 35 23 40 40 25 Cuscuta campestris
QUESTION 6 (contd.)
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Which of the plants you have ticked under Actual in Table 1 are the most significant ? Please list your top 1- 7 species. ANSWERS Over 62 species were recognised as the most significant; and of these, 46 species originated from the prompt list thus respondents volunteered a further 16 species. There was not much agreement amongst respondents as to which species were most significant, and only four species were given as significant by 20% of respondents. Most species got only a few ‘votes’. The implications of this are that Basin-wide management programs will need to deal with several species. The four significant species were (in descending order, counts from 18 – 12): Weeping willow Salix babylonica; lippia Phyla canescens; Blackberry Rubus fructicosus; other willows Salix spp.
Notable features of this list of the top four species are: • All four were also the most widespread pests (Table A2.1) • All are associated with the riparian zone rather than with aquatic habitats.
The following 12 species were each seen as significant by 4 to 9 respondents: Noogorra burr Xanthium occidentale; Mother of millions Bryophyllum tubiflorum; Crack willow Salix fragilis; Parthenium weed Parthenium hysterophorus; Water lettuce Pistia stratoites; Grey willow Salix cinerea; Johnson grass Sorghum helepenese; privets Ligustrum spp.; Arrowhead Sagittaria graminea; Alligator weed Alternanthera philoxeroides; Spear thistle Cirsium vulgare; Water hyacinth Eichhornia crassipes.
Notable features of these 16 significant species (including the four above) are: • Overlap (8 / 16 species) with the most widespread species, indicating that characteristics of being widespread and being significant are poorly correlated and need to be assessed separately. • The range of growth-forms includes aquatic macrophytes. • The growth-forms with the most species are perennial herbs and trees (Table A2.3). • Four species, Alligator Weed, Blackberry, Parthenium Weed, and Willows, are Weeds of National Significance (WONS).
Further work would be needed to determine if these species are listed because of their intrinsic threats to aquatic and riparian habitats or because respondents are influenced by state and federal information. If the latter, then this could be useful feedback on education programs.
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Table A2.3: The 16 species / taxa most frequently cited as significant in 50 replies. FORM and Family Genus Species Common Name TREES Salicaceae Salix babylonica Weeping willow Salix fragilis Crack willow Salix cinerea Grey willow Salix spp. Other willows and hybrids SHRUBS Oleaceae Ligustrum spp Privets Rosaceae Rubus fructicosus Blackberry GRASSES - perennial Poaceae Sorghum halepense Johnson grass HERBS – perennial Crassulaceae Bryophyllum tubiflorum Mother of millions Verbenaceae Phyla canescens Lippia Alismataceae Sagittaria graminea Arrowhead Amaranthaceae Alternanthera philoxeroides Alligator Weed Pontederiaceae Eichhornia crassipes Water hyacinth HERBS – annual Asteraceae Cirsium vulgare Spear thistle Parthenium hysterophorus Parthenium weed Xanthium occidentale Noogorra burr HERB –aquatic Araceae Pistia stratiotes Water lettuce
Geographic Variations across the Basin. Although this is fairly coarse spatial analysis, there are regional differences in which species are recognised as most significant pests (Table A2.4). Note that:
• Some species were considered as a pest only in one part of the Basin. • Species considered a significant pest only by respondents in the northern MDB were: Privets Ligustrum spp; Johnson grass Sorghum halepense; Mother of millions Bryophyllum tubiflorum; Water lettuce Pistia stratiotes; Parthenium weed Parthenium hysterophorus. • Species considered more of a significant pest in northern rather than southern lowlands & slopes are: Lippia Phyla canescens • Species considered more of a pest in southern rather than northern lowlands & slopes are: Arrowhead Sagittaria graminea; Blackberry Rubus fructicosus agg.
An important implication of these geographic variations is that any programs targeting individual species may be seen as having a regional focus or benefit, and therefore programs will need to be developed that deliver benefits beyond the area of current infestations; for example, by targeting a group of species; or by targeting control and prevention for a particular species; or by developing generic or theoretical knowledge.
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Table A2.4: Geographic variations in species of significane. Data are percentage frequency of that species being cited as a pest for each bio-region, with number of respondents per bio-region at top of column. The16 pest species are taken from the list of 12 in Table A2.3. NC = not calculated. Genus Species RIV SHE NSW DRP BSS (n=17) (n=13) NSS (n=10) (n=12) (n=10) TREES Salix babylonica 23 38 40 40 42 Salix fragilis NC NC NC NC NC Salix cinerea NC NC NC NC NC Salix spp. NC NC NC NC NC SHRUBS Ligustrum spp 0 0 0 20 25 Rubus fructicosus 29 46 47 20 17 GRASSES Sorghum halepense 60 02033 HERBS – perennial Bryophyllum tubiflorum 0 0 0 40 58 Phyla canescens 29 23 40 90 75 Sagittaria graminea 29 8 13 0 0 Alternanthera NC NC NC NC NC philoxeroides NC NC NC NC NC Eichhornia crassipes HERBS - annual Cirsium vulgare NC NC NC NC NC Parthenium 0 0 0 30 50 hysterophorus 18 8 13 20 17 Xanthium occidentale HERBS – Aquatic Pistia stratiotes 00 03033
QUESTION 7: Please indicate which species in Table 1 you consider to be problem or pest plants of the future. This question was intended to reveal incipient problems and set priorities for future actions or programs. ANSWERS One hundred (100) species were nominated from the prompt list of 124 species and a further 16 species were volunteered, giving a total of 120 species perceived as threats in the future.
Most respondents listed 1-10 species but five respondents gave more than 20 species. Coincidentally, these five respondents were all reporting on lowland floodplain systems (Barmah, Lachlan, Ovens and Kiewa, Paroo, Gwydir) and have a background in floodplain and aquatic vegetation biology / ecology.
Only two species, Water hyacinth Eichhornia crassipes and Salvinia Salvinia molesta, were rated as potential threats by more than 10 respondents (ie by more than 20% of survey).
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Table A2.5: The 12 species / taxa cited as a threat by at least 5% of respondents FORM and Family Genus Species Common Name TREES Oleaceae Olea europea Olive Salicaceae Populus spp Poplars Salix spp. Other willows and hybrids HERBS – perennial Verbenaceae Phyla canescens Lippia Amaranthaceae Alternanthera philoxeroides Alligator Weed Cabombaceae Cabomba caroliniana Cabomba Hydrocharitaceae Elodea canadensis Elodea Pontederiaceae Eichhornia crassipes Water hyacinth Haloragaceae Myriophyllum aquaticum Parrot’s feather HERBS – annual Clusiaceae Hypericum perforatum St John’s Wort HERBS –aquatic Araceae Pistia stratiotes Water lettuce FERNS – aquatic Salviniaceae Salvinia molesta Salvinia
The twelve species most frequently rated as potential threats by at least 10% of respondents (with scores of 5-14) were (in descending ranked order): Water hyacinth Eichhornia crassipes; Salvinia Salvinia molesta; lippia Phyla canescens; Alligator Weed Alternanthera philoxeroides; Parrot’s feather Myriophyllum aquaticum; Poplars Populus spp.; Cabomba Cabomba caroliniana; elodea Elodea canadensis; St John’s Wort Hypericum perforatum; olive Olea europea; Water lettuce Pistia stratiotes; willows Salix spp.
Significant features of this list are: • Prevalence (7 / 12 species) of aquatic macrophytes and low numbers (2 / 12) of terrestrial species, only olive and St John’s wort. • Presence of four WONS species, Alligator Weed, Cabomba, Salvinia and Willows
Geographic variations: Sample sizes are smaller because of the lower response rate for Question 7 and because respondents nominated fewer species than in Question 6. Only species that rated as potential by at leat 7 respondents (14% of total) are considered. Species perceived as being a potential threat more in northern lowland-slopes bio-regions of the Basin are: Water hyacinth Eichhornia crassipes Species perceived as being a potential threat more in the southern lowlands-slopes bio-regions of the Basin are: Alligator weed Alternanthera philoxeroides; Parrot’s feather Myriophyllum aquaticum There was less evidence of north-south differences in species considered to be potential threats than with actual or current pests (TableA2.6).
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Table A2.6: Geographic variation in species perceived as potential pests. Data are percentage frequency of that species being cited as a pest for each bio-region, with number of respondents per bio-region at top of column. The 6 pest species are taken from the list in Table A2.5, and have a minimum score of 7 or 14% of responses. Genus Species RIV SHE NSW DRP BSS (n=17) (n=13) NSS (n=10) (n=12) (n=10) TREES Populus 18 15 13 20 17 HERBS – perennial Phyla canescens 24 23 33 20 25 Alternanthera philoxeroides 29 10 27 10 8 Eichhornia crassipes 29 15 13 50 42 Myriophyllum aquaticum 24 15 27 10 8 FERNS – Aquatic Salvinia molesta 29 31 33 30 33
QUESTION 8: Indicate – for your geographic area – which of the following 12 characteristics are most important in the pest plants in aquatic and riverine habitats. Please tick as appropriate This question explored respondents knowledge and experience of pest plants by asking them to nominate which ecological attributes were typical of pest species for their area. A list of 12 ecological attributes was given as prompts; and answers were not exclusive (ie all 5 sources could be nominated): Sources of species (5 given) Dispersal (3 mechanisms given) and Attribute (4 attributes), and Other. The maximum possible score was 46. ANSWERS Sources: Respondents considered garden escapes and crop weeds (16 and 15 respectively) as equally important. Aquarium plants and commercially grown plants were seen as slightly less important (10 and 11 respectively) and rubbish dumping the least (7). One respondent suggested agricultural escapes as a source.
Dispersal: Respondents considered water was the most important dispersal attribute (score 32) with dispersal by birds or due to adherence (burrs) much less important (15 and 16 respectively). Wind and animal vectors were suggested (2 and 3 respectively).
Attribute: The most important ecological attributes for pest species were persistence (a generic attribute, deliberately chosen to be non-specific) and capacity to re-grow from fragments (27 and 26 respectively). Having long-lived seeds and suckering (19 and 15 respectively) were also important but less so.
There are two interesting points about these answers, that relate to understanding and general ecological knowledge of the respondents. • Some understanding of sources and attributes can be obtained from reference books or species information leaflets (eg whether it is an aquarium plant, grown commercially etc) or from field observations
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(eg rubbish dumping as a source, suckering as an important attribute). This indicates the importance of providing good ecological knowledge as well as control information. • There are two attributes for which there is very little published information, long-lived seeds and water dispersal, yet these were both rated quite highly by respondents (19 and 32 respectively). As neither seed longevity nor water dispersal can be measured readily from field observations, high scores for these two attributes suggests that respondents are making field observations consistent with these.
[3] Temporal changes
QUESTION 9: In Q-5 you listed the top 1-7 pest plant species for your geographic area. Are these the same 1-7 species you would have listed when answering this question ten years ago ? The purpose of this question was to record whether the weed flora had substantially changed, and if so in what way. The expectation, however, was that there would be relatively little evidence of change because of recurrent institutional changes and cut-backs with the probably consequence that only a few professional staff would remain in an area or retain relevant responsibilities through time. ANSWERS: It was not surprising, therefore, that the response rate for this question was generally low: Nearly half (46%) of respondents failed to answer this question, with many indicating they either lacked the knowledge to make this assessment or were relative newcomers (of 1-2-3 years standing) to the area.
Although there was some evidence of stability, ther was much more evidence of change in the weed flora across the Basin. • Approximately one third (34%) of respondents considered the weed flora had changed whereas only one fifth (20%) considered it the same as ten years ago. • There was no evidence of geographic trends, ie respondents reporting change and respondents reporting no change were not strongly associated with any particular bio-region.
Respondents commented on the types of changes. Some referred to ecological changes such as changes in abundance, shifts in dominance or arrival of new species, as well as the difficulty of making such an assessment against a background of year-year changes. Others referred to changes in awareness of field observers due to increased education or to change in responsibilities (eg participation in regional committee).
The following points were made in relation to change: Increasers: Species that have increased or are increasing within this ten-year timeframe are (with number of respondents volunteering that species in brackets): Water lettuce Pistia stratiotes (1), Bridal creeper Myrsiphyllum asparagoides (1), alligator weed Alternanthera philoxeroides (4), lippia Phyla canescens (3), water plantain Alisma lanceolatum (1) arrowhead Sagittaria graminea (5); needle grass Nasella neesiana (2). Characteristics of these increaser species are: mainly aquatic plants; species that have been target of campaigns; or both.
Based on replies from respondents, the most notable changes in this 10-year frame are:
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• Water lettuce Pistia stratiotes is a recent arrival and northern threat to Warrego / Paroo catchments (not distinguished in the response). • Alligator weed Alternanthera philoxeroides is a relatively recent (ie last 10 years) threat, is of most concern in constructed habitats such as irrigation areas associated with the lowland Murray and Murrumbidgee Rivers, and hence in natural riverine and floodplain habitats immediately downstream of these. These are both large and highly regulated rivers in the southern part of the Basin. • Lippia Phyla canescens is expanding in different parts of the Basin, on lowland parts of the north-eastern rivers and along the main stem of the River Murray. (This is in addition to it being already established on black soils of the Lachlan and Gwydir Rivers, in particular). • Arrowhead Sagittaria graminea is strongly indicated as an expanding species in the lowland River Murray system. Two respondents commented that this plant has changed from being present ten years ago to being top of the weed list to-day. Arowhead was nominated as an increaser by five respondents, the highest number. • Needle grass Nasella neesiana is expanding in the slopes / upland areas of major rivers such as the Murrumbidgee and Gwydir River systems. This is not an obligate aquatic or riparian species.
Implications of there being relatively few skilled and informed observers with a time-frame longer than a few years are that: • Temporal variability is a characteristic of natural riverine environment within the Murray-Darling Basin, but relevant local experience and field knowledge are not well-placed to capture or transfer this. • Short-term field observations of temporal changes in weed flora are unlikely to have requisite field experience to sift substantial changes from transient or seasonal abnormalities.
[4] Impediments and challenges The ecological literature recognises that riparian zones, being zones of transition or ecotones between land and water systems, not only share some of the characteristics of both terrestrial and aquatic ecosystems but as a result have some unique combinations of spatial and temporal characteristics. The purpose of the questions in this section was explore whether this ecological distinctiveness was understood (even intuitively) by respondents and also whether this posed specific management issues and what these might be.
QUESTION 10: In your geographic area, are there any special considerations or special challenges to weed management in aquatic and riparian habitats in the riverine environment ? ANSWERS: Yes, was the resounding answer to this question (75% of respondents). Very few respondents (6%) considered that the riparian zone posed no specific management problems, and a small number did not know (15%). Overall response rate was high (81%) as 4% did not answer at all.
However, although respondents were in fairly solid agreement that the riverine environment posed specific challenges to weed management, this was not supported by the extensive replies or examples. Only some of the examples and replies could be directly linked to the characteristics of riparian or aquatic habitats (see below). Many of the examples or elaborations were expressions of frustration that could be applied to other aspects of natural resource management or other ecosystems.
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RIPARIAN OR AQUATIC CHALLENGES LISTED INCLUDE: Specific challenges to pest plant management or control posed by aquatic or riverine habitats were: Accessibility: some riparian habitats are difficult to access, being either remote or in steep gorge country, and this makes it difficult to detect stands or to implement a control program. Some riparian habitats are in areas of low population density, thereby reducing the likelihood of chance detection. Catchment perspective: Difficult to involve people in a catchmnet perspective of weed control and management. Chemicals: Various comments, some negative some positive some ambiguous, were made relating to use of chemicals in riparian zone, or in aquatic or flowing habitats as follows; • Little known about rights and responsibilities • Paradoxical situation whereby some of the most successful and useful chemicals can have a serious downstream effect (eg via sediment transport). • Usage is becoming increasing regulated • Downstream water quality must be protected Conflicting Values: Weed control may be desirable and an acceptable goal in principle, but sometimes the implementation of a control program can interfere with or prejudice other societal values; or a species may have two kinds of values. Several examples (11) were given where there were dual social values, as follows: • Willows Salix spp. and poplars Populus spp. can be seen as weeds (negative) and as bank stabilisers or as cultural heritage (positive). • Cumbungi Typha spp. could be controlled or reduced by water level manipulations but this is not possible as other interests require that the water level be maintained (an example is permanent water levels in parts of Willandra Creek). • Conservation values conflict with weed control needs and practices, most notably in high value wetlands; the cases of lippia Phyla canescens and water hyacinth Eichhornia crassipes in the Gwydir wetlands was mentioned by 3 respondents. • Cumbungi Typha spp. and Common Reed Phragmites australis are both native plants important in bank stabilisation and as habitat, yet some communities want to clear these plants out. Detection and early warning; the value of this and the difficulties of implementing this in habitats characterised by inaccessibility, remoteness, low population density. Skills and expertise: there is a general lack of skills and expertise for dangerous (physical and / or chemical) means if implementing control of undesirable species in the riparian zone. Stock grazing in the riparian zone: grazing pressure is / has shifted species composition of riparian zone. Water regime: Various issues raised showing that the complexity of the relationship between vegetation dynamics, invasive and opportunistic species and flow regime and changes to flow regime is not well understood. For example: • Rivers with flow regimes that are extremely variable and unpredictable are difficult to manage with respect to weed invasions. • Anticipating that return of environmental flows would increase the habitat available for aquatic weeds; whilst not commenting on the stresses resulting from reduced flows and river regulation on riparian plant communities and natural regeneration processes.
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GENERIC ISSUES Generic issues, ie not specific to the riverine environment, raised were: Public awareness: of which are introduced or pest species; and of what ecological issues result from this and from public activities Control options: Respondents were more pre-occupied with chemical controls. • Respondents commented on a general lack of biological controls. Poor anticipation: the consequences or otherwise of implementing weed control program are rarely articulated in economic terms (other than program costs); similarly, the consequences of not undertaken a control program are rarely given. There is a general inability to extrapolate or predict outcomes. Identification and understanding of weed species: Two issues raised were: • Special publications needed and being developed in some states to assist landholders, public and agency staff to identify weed species. • Failure to understand that native species can be invasive and a nuisance Limitations: Limitations commented on (not in great detail) were resources, funding, research; choice of chemicals for use in riparian zone; choice of control options. Comment was also made about: • Misplaced effort: • Restoration and Post-control strategies • Scope and Size of task • Persistence of weed species
QUESTION 11: Which of the following would make it easier to prevent the establishment of weed species in aquatic and riparian habitats, or to control weeds already established in these habitats in your geographic area ? The purpose of this question was to determine directly from those involved their perspectives on factors constraining effective weed management. A prompt list of eleven factors was provided with no restrictions on the number of factors that could be selected. ANSWERS: The question touched most respondents, and the response rate was high (91%). Scores for the eleven factors ranged from 29 to 11, out of a maximum of 42.
Answers show some overlap with previous question, and arranged in descending order are: 29 A more informed public 28 More people / staff / community neighbours involved 25 Species control strategies, options 24 Control of adjacent land use and/or people activities 23 More choice of control options suitable for use near waterways 22 Post control strategies to prevent further exotics establishing 21 Species information, identification, ecology 18 Better understanding of the hydrology of aquatic riparian habitats 17 More time for searching, follow-up, controls 15 Search-efficient strategies for early detection 11 Contact with equivalent people elsewhere
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Notable features here are: • Constraining factors involving people and especially the public scored high. By implication, behaviour of the public was a major constraint (first and fourth items on list). • Species information and controls also scored high. • Generic types of knowledge (hydrology; early-detection strategies) were not seen as major impediments. • Understanding hydrology was not seen as a major impediment, despite the widespread acceptance of water dispersal as a means of propagule dispersal.
[5] RESEARCH PRIORITIES
QUESTION 12: In addition, you may know of research and investigations needed to address critical information gaps, either for your region or in relation to certain species or habitats, or to management practice. Please describe such projects below. This question aimed to tap the experience and expertise of persons working in the area of weed research and / or weed management, to establish what research might be needed. ANSWERS: Response rate to this question was low, with only 51% of respondents making suggestions on research priorities. This low response rate did not correspond to any professional characteristic or experience, ie those making or not making research suggestions did not fall neatly into any professional category. It may be linked to short experience noted above.
Although response rate was low, a total of 24 research projects were suggested, and these have been grouped here into seven research categories. The groupings reveal some important differences between aquatic and riparian habitats.
[1] Potential: Predicting the spread, eventual distribution and likely impacts of new or potential weeds is information that would greatly assist regional managers seeking support for an early strike, or help set priorities for budgets or activities. • Visual products may be useful, such as species leaflets, potential distribution maps.
[2] New controls and control strategies: Several respondents called for research to develop new control or control strategies, including biological control, for in-stream and riparian species, but taking a broad rather than a single-species approach. There was an emphasis on effectiveness and efficiency, with careful matching of species to technique. • The implications of calls for new controls are that currently available control methods are not effective.
[3] Single species control projects: these were intensive study of single species, combining growth, ecology and/or control, sometimes combined under an umbrella term such as “integrated” management. All plant species that were suggested here (see below) were aquatic or in-stream species: no riparian species were suggested for single species management. Arrowhead Sagittaria (nominated by 4 respondents); lippia Phyla canescens (nominated by 2 respondents); and water hyacinth Eichhornia crassipes, cumbungi Typha spp., common reed Phragmites australis, alligator
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weed Alternanthera philoxeroides and parrots feather Myriophyllum aquaticum (nominated by 1 respondent each). These seven species are a mixture of ‘new’ and ‘old’ weeds and are alien species, except for the two emergent macrophytes that are indigenous. ‘New’ as used here refers to species that have become important weeds relatively recently (decade or less) or are just beginning to establish or are showing a surge into new habitats. Examples of ‘new’ weeds are Sagittaria graminea, Alternanthera philoxeroides, Phyla canescens and Myriophyllum aquaticum. ‘Old’, in contrast, refers to species that are already well-recognised as a serious threat or that have, through time, shown cycles of being significant then not so significant. Examples of these are Eichhornia crassipes, and Typha spp. and Phragmites australis (the last two are native species). • The implications of this suite of single-species control / management projects are that certain aquatic and floodplain species are so threatening or potentially threatening that they require dedicated effort; and in the case of the aquatics, this is probably linked to the increasing constraints use of chemicals.
[4] Restoration: the four projects in this category addressed very similar themes of seeking to ensure a viable non-weedy vegetation community following an extensive control program in the riparian zone. Two projects were concerned with ensuring that control programs of woody riparian species notably of willows Salix spp., blackberry Rubus fructicosus aggreg. had suitable follow-up vegetation planning, rather than leaving subsequent colonisation and establishment processes to chance. The other two projects focused on native riparian grasses as follow-up species, their selection and propagation.
[5] Grazing in the Riparian Zone: Using tactical grazing in the riparian zone and using the interactive effect of grazing and flooding regime to suppress undesirable non-native species and encourage desirable native species was the core of 3 suggestions. • The implications here relate to the importance – and difficulty - of accommodating multiple land uses and of taking the optimistic view of searching for a win-win land management. The strategy that is usually suggested for protecting the riparian zone is stock exclusion by fencing.
[6] Evaluation: Formal assessment of management activities and control strategies as a feedback mechanism, plus an investigation into failures. • The implication here is that retrospective evaluations are rarely done. More time for follow-up work and controls was not seen as an impediment to management (see above).
[7] Scientific and Generic knowledge: this group of research projects has no common theme but are grouped together as the information and understanding called for will introduce new ideas and new concepts in pest / weed science. Some ideas were proposed but with very little detail. • Use of introduced plant species by native biota: given the decline in natural habitat it is important to understand if and how native biota may now be using introduced plant species as a food source, habitat, refuge etc. These ecological values need to be understood, and alternatives considered, before implementing a weed control program. • Tolerance of floodplain weeds to increasing salinity. • Development of a weed classification / type system: based on type of impact, whether economic or environmental, and other management criteria.
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• Ecology-flow relationships: this knowledge base in Australia is almost entirely focused on native species, and placed in context of environmental flows and river rehabilitation. This branch of aquatic and riparian vegetation ecology needs to expand to understand how changes in flow regime may favour non- native species, and what the potential is for reversing this.
These research suggestions show that respondents still see a need for conventional pest management approaches (eg species control measures) mixed with newer more strategic approaches that move away from species focus to work at a landscape or system level.
[6] INFORMATION PRODUCTS AND NEEDS Questions 13 and 14 aimed to establish what products and resource materials were is use and valued in relation to weeds and weed control, in relation to aquatic and riparian plants. Question 15 aimed to find out what educational materials and packages were or had been in use. ANSWERS: Answers showed that these questions were not well discriminated by respondents, thus suggesting inappropriate or inadequate design for the survey, so replies to these three questions are rolled together.
INFORMATION PRODUCTS Respondents used a range of resource material, as summarised below. [1] Government Agency extension products: leaflets, newsletters. Items mentioned in particular were: DNRE LandCare notes, NRE Pest Plants, QDNR Pest Facts
[2] Leaflets: considered particularly good value by some respondents because easy to up-date, easy to compile and assemble, succinct and comprehensive.
[3] Books and special reports: The types of books used varied enormously from standard academic botanical works, regional vegetation guides, habitat-specific guides, and included a number of weed books. Books specifically mentioned were: • Anderson (1993) Plants of central Queensland • Aston (1973) Aquatic plants of Australia • Auld and Medd (1987) An illustrated guide to the weeds of Australia • Cummins (1996, 1999) Weeds: The ute guide • Cunningham et al. (1981, 1992) Plants of Western New South Wales • Higgins and Lucy Weeds of southern Queensland • Lamp and Collett (1989) A Field Guide to weeds of Australia • Parsons and Cutherbertson (1992, 2001) Noxious Weeds of Australia • Reece and Luxton Common weeds on streambanks and control methods • Sainty and Jacobs (various editions): Waterplants in Australia • Flora of Victoria • Flora of New South Wales
[4] Special Publications: a number of special publications were nominated as having proved particularly useful, usually these targeted a local area or local issue. Examples are: Small field guides,
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[5] Web pages: Web pages were mentioned only twice. NSW Agriculture and QDNRM.
Notable features of this list of useful resource materials are: • Importance of hard copy material • Importance of reference books • Very few references to Web material • Diversity of sources for resource materials: government agency material, industry produced, private and academic publications, national and local publications.
QUALITY PRODUCTS Respondents were particularly enthusiastic about three products. • Cremer (1995, 1999): Articles and publications by Kurt Cremer on willows were specially mentioned by a number of respondents and cited as material of high educational standard. • Sainty and Jacobs (1994); guide(s) to water plants • Lucy et al (1995): Agdex special publication on lippia These three sets of publications provide species identification, biology/ecology and management (if known) based on considerable specialist scientific detail in a readable form, use a mixture of diagrams and photographic material, and are clearly laid-out.
EDUCATIONAL PRODUCTS Items specially mentioned as useful under educational products were; • Books by Sainty and Jacobs • Publications and Field days on willows by Cremer • Study units such as Agronomy at University of New England, Integrated Weed management at Charles Sturt University, Wagga Wagga.
NEEDS Items given as ‘needs’ were a curious mixture (see below); at least one of these indicated that the respondent was unaware of material that other respondents considered excellent (eg Lucy’s Agdex on lippia). More information on CRC for Weed management Systems Identification products Information on lippia: the respondent reported ‘nothing on lippia’ Biological controls for weed species More information on the hydrological requirements of weed species Seed viability and longevity Plant biology and life cycles List of riparian zone plant species, plus life histories, dispersal ecology, and control options suitable for use near water.
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