final report Project Code: NBP.357 Prepared by: Jenny Barker, Rod Randall,Tony Grice Co-operative Research Centre for Australian Weed Management Date published: May 2006 ISBN: 1 74036 781 2 PUBLISHED BY Meat and Livestock Australia Limited Locked Bag 991 NORTH SYDNEY NSW 2059 Weeds of the future? Threats to Australia’s grazing industries by garden plants Meat & Livestock Australia acknowledges the matching funds provided by the Australian Government to support the research and development detailed in this publication. This publication is published by Meat & Livestock Australia Limited ABN 39 081 678 364 (MLA). Care is taken to ensure the accuracy of the information contained in this publication. However MLA cannot accept responsibility for the accuracy or completeness of the information or opinions contained in the publication. You should make your own enquiries before making decisions concerning your interests. Reproduction in whole or in part of this publication is prohibited without prior written consent of MLA. Weeds of the future? Threats to Australia’s grazing industries by garden plants Abstract This report identifies 281 introduced garden plants and 800 lower priority species that present a significant risk to Australia’s grazing industries should they naturalise. Of the 281 species: • Nearly all have been recorded overseas as agricultural or environmental weeds (or both); • More than one tenth (11%) have been recorded as noxious weeds overseas; • At least one third (33%) are toxic and may harm or even kill livestock; • Almost all have been commercially available in Australia in the last 20 years; • Over two thirds (70%) were still available from Australian nurseries in 2004; • Over two thirds (72%) are not currently recognised as weeds under either State or Commonwealth legislation. Collectively, these species have the potential to establish as weeds across Australia, affecting all major sectors of the grazing industry. Recommendations recognises that Meat and Livestock Australia can play an important role in increasing awareness of weed risks and costs through the education of graziers and the wider public; by lobbying the state/territory and federal governments to tighten legislation relating to the importation, sale and movement of weed species; and in promoting, and appropriately responding to, weed risk assessments of plants already in Australian gardens. Page 2 of 137 Weeds of the future? Threats to Australia’s grazing industries by garden plants Executive Summary This report has been produced by the CRC for Australian Weed Management. It extends an earlier publication (Grice 2003) which reported on naturalised plant species that present existing and emerging weed threats to Australia’s grazing industries. The research is underpinned by the Western Australian Department of Agriculture and Food’s “Plant Database” (Randall 2006). The database collates information from c. 1.5 million species-related records drawn from over 3000 publications and presently treats approximately 576,000 plant taxa. Used in conjunction with regional climate zones and by extrapolating from overseas weed experiences, the database provides a unique opportunity to identify weeds currently present in Australian gardens that may threaten Australia’s agricultural industries or natural environment in the future. The research focuses on plants that are currently available in Australian nurseries because most of Australia’s naturalised flora has been introduced for ornamental purposes (Groves, Boden & Lonsdale 2005: 18, Spencer 2005: 8; Anonymous 2005: 3; Virtue, Bennet & Randall 2004). These plants also present the most immediate threat compared to species outside Australia and being in commercial trade enjoy a level of dispersal well beyond that of natural means. The report identifies 281 introduced garden plants (Appendix 1) – as well as 800 lesser priority species (Appendix 2) – which present a significant risk to Australia’s grazing industries should they escape from Australian gardens and naturalise. The research evaluates these risks as a precursor to formal weed risk assessment. Of the 281 species: • Nearly all have been recorded overseas as agricultural or environmental weeds (or both); • More than one tenth (11%) have been recorded as noxious1 weeds overseas; • At least one third (33%) are toxic and may harm or even kill livestock; • Almost all have been commercially available in Australia in the last 20 years; • Over two thirds (70%) were still available from Australian nurseries in 2004; • Over two thirds (72%) are not currently recognised as weeds under either State or Commonwealth legislation. Whilst studies of predicted economic impact have not been conducted, previous research (Centre for International Economics 2001: 24, 26) has predicted that infestations of just two of the 281 species – Nassella tenuissima (Trin.) Barkworth and Onopordum nervosum Boiss. – could cost Australia up to A$82m over the next 40-60 years. 1 This term is usually used for a plant that has been banned by legislation in recognition of the significant threat it presents to a country’s economy or environment (Spencer 2005: 12). Page 3 of 137 Weeds of the future? Threats to Australia’s grazing industries by garden plants Case studies are provided for 11 taxa representing a variety of vegetation types – herbs, trees, shrubs, vines and grasses: • Asclepias syriaca L. • Equisetum L. spp. • Festuca gautieri (Hackel) K. Richter • Hieracium L. spp. • Inula helenium L. • Lonicera L. spp. • Miscanthus floridulus (Labill.) Warb. ex K. Schum. & Lauterb. • Nassella tenuissima (Trin.) Barkworth • Onopordum nervosum Boiss. • Ornithogalum nutans L. • Tamarix gallica L. Maps of predicted Australia distribution indicate that, collectively, these species have the potential to establish as weeds across Australia, affecting the four major sectors of the grazing industries: beef, dairy, lamb and wool. Infestations of these 11 species alone have the potential to cost the grazing industries of Australia millions of dollars. Recommendations recognise the role that Meat and Livestock Australia can play in increasing awareness of weed risks and costs through the education of graziers and the wider public; by lobbying the state/territory and federal governments to tighten legislation relating to the importation, sale and movement of weed species; and in promoting (and appropriately responding to) weed risk assessments of plants already in Australian gardens. Foremost amongst the report’s recommendations are the formal weed risk assessment of the 1081 listed species and the subsequent withdrawal from sale and prohibition from importation into Australia of high-risk species. Page 4 of 137 Weeds of the future? Threats to Australia’s grazing industries by garden plants Contents Page 1 Background - Section......................................... 7 1.1 Introduction ................................................................................... 7 1.2 Context........................................................................................... 7 1.2.1 Five major areas of weed impact..................................................... 7 1.2.2 Three major reasons for plant introduction to Australia ................... 8 1.2.3 Three stages of weed development ................................................ 8 1.2.4 Three weed groups ......................................................................... 9 1.2.5 Australia’s grazing industries......................................................... 10 1.2.6 Invasive (Group 1) weeds.............................................................. 11 1.2.7 Emerging (Group 2) weeds ........................................................... 13 2 Project Objectives............................................. 15 3 Methodology - Section ..................................... 16 3.1 WA Department of Agriculture & Food’s “Plant Database”..... 16 3.2 Query Check commercial availability ........................................ 18 3.3 Collect relevant information....................................................... 18 3.4 Remove species less likely to establish in Australia ............... 18 4 Results and Discussion ................................... 19 4.1 281 garden plants that threaten grazing industries ................. 19 4.2 Analysis........................................................................................ 20 4.2.1 Family............................................................................................ 20 4.2.2 Growth form/longevity ................................................................... 21 4.2.3 Origin............................................................................................. 21 4.2.4 Weeds of the environment & agriculture ....................................... 22 4.2.5 Toxicity .......................................................................................... 23 4.2.6 Weed history ................................................................................. 23 4.2.7 Climatic suitability.......................................................................... 23 Page 5 of 137 Weeds of the future? Threats to Australia’s grazing industries by garden plants 4.2.8 Propagule pressure/plant availability from nurseries ..................... 23 4.2.9 Existing legislation on 281 species................................................ 29 4.3 11 case studies............................................................................ 34 4.3.1 Selection of the 11 profiled