Lower Hunter Koala Study Final

Funded by the Department of Sustainability, Environment, Water, Population, and Communities through the Sustainable Regional Development Program June 2013 Lower Hunter Koala Study

DOCUMENT TRACKING

ITEM DETAIL Project Name Lower Hunter Koala Study Project Number 12SYDNRM-003 Robert Mezzatesta Project Manager PO Box 20529 World Square, NSW 2002 (02) 8536 8650 Prepared by Sophie Powrie, Daniel McKenzie, Andrea Sabella, Mark Walton, Steve Ward Approved by SW Status FINAL Version Number 1 Last saved on 19 June 2013

Koala photo from 2004 Port Stephens Community Monitoring Survey; Expert Koala Cover photos Workshop Feb 2013, Newcastle; Map of Data Audit Results Point Koala Records @ February 2013, ELA

This report should be cited as ‘Eco Logical Australia 2013. Lower Hunter Koala Study. Prepared for Dept Sustainability, Environment, Water, Population and Communities’.

Creative Commons

This report is licensed under Creative Commons Attribution 3.0 Australia licence

ACKNOWLEDGEMENTS This document has been prepared by Eco Logical Australia Pty Ltd with support from Paul Keighley and Alistair Cockburn, SEWPaC. We gratefully acknowledge the input of the expert workshop participants; Anthony Marchment (PSC), Dan Lunney (OEH), David Paull (PSC), Geoff Bartlett (HKPS), Indrie Miller (OEH), Lucas Grenadier (OEH), Mark Roselle (PSC), Paul Keighley (SEWPaC), Ray Williams (Ecotone) and Robbie Economos (LMCC).

Disclaimer The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for Sustainability, Environment, Water, Population and Communities. While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication.

Contents

Executive Summary ...... 1

1 Introduction...... 3 1.1 Context ...... 3 1.2 Study Brief ...... 3

2 Methods...... 5 2.1 Overview...... 5 2.2 Existing knowledge of Koala populations and habitat in the Lower Hunter ...... 5 2.3 Stakeholder Consultation ...... 6 2.4 Koala Habitat modelling...... 6

3 Results...... 14 3.1 Koala Ecology...... 14 3.2 Historical Distribution in the Lower Hunter ...... 15 3.3 Present Population Distribution ...... 15 3.4 Tree species ...... 17 3.5 Habitat modelling...... 17 3.5.1 Model Limitations...... 26

4 Discussion...... 27 4.1 What is the current population number of koalas in the Lower Hunter region? ...... 27 4.2 What is the rate of change in this population and has this rate changed? What are the major and minor causes behind this?...... 27 4.3 What criteria should be used to identify high priority habitat areas?...... 27 4.4 What is the current extent and quality of koala habitat in the region? ...... 28 4.5 What are the local key threatening processes and recommended conservation measures for koalas to assist with decision making for the Lower Hunter Regional Strategy and Regional Conservation Plan? ...... 29

5 Conclusions and Recommendations ...... 32

6 References ...... 34

Appendix A...... 39

Abbreviations

ABBREVIATION DESCRIPTION

CKPoM Comprehensive Koala Plan of Management

ERIN Environmental Resource Information Network

GDE Groundwater Dependent Ecosystem

GHM Greater Hunter Mapping (version 4 by NSW Office of Environment and Heritage)

GIS Geographical Information System

HKPS Hunter Koala Preservation Society

LGA Local Government Area

LH Lower Hunter

LM Lake Macquarie

NATF Native Animal Trust Fund

OEH NSW Office of Environment and Heritage

PSC Port Stephens Council

SEWPaC Dept Sustainability, Environment, Water, Population and Communities

Executive Summary

This study was commissioned by the Department of Sustainability Environment, Water, Population and Communities (SEWPaC) to contribute to regional sustainability planning that will lead into a strategic assessment of future development in the Lower Hunter region under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The study area included the Local Government Areas (LGAs) of Cessnock, Lake Macquarie, Maitland, Newcastle, and Port Stephens. This study utilises existing data available in the public domain to inform specific key information gaps regarding conservation planning needs of the koala in the Lower Hunter. The koala is listed as a vulnerable species in NSW under the EPBC Act and the NSW Threatened Species Conservation Act 1995 (TSC Act).

The koala population at Port Stephens is a high profile one, and considerable research work has been undertaken within the LGA, but nevertheless, there remain information gaps for this area. The level of knowledge of the koala within the other LGA’s in the study area is poor, with much less information available for this study.

Due to these data limitations, it is not possible to provide a reliable population estimate of the koala for the Lower Hunter region. Within Port Stephens, where more data is available, the koala population is estimated to be between 350 and 500 individuals (Phillips et al. 1996). A number of koala sightings have been recorded in the Cessnock and Lake Macquarie LGAs, but population size(s) are unknown.

It is similarly not possible to reliably estimate rate of change of koala populations within the region. However anecdotal observations from Port Stephens LGA suggest that changes in koala numbers are not uniform, with some areas decreasing and one population at Boat Harbour/One Mile reported to be increasing.

The current extent and quality of habitat across the Lower Hunter was modelled as part of this study, based on input from an expert workshop and a GIS modelling process. The resulting outputs were converted to low, moderate, high and very high koala habitat rankings. The greatest areas of very high and high ranked habitat were mapped in Port Stephens, Cessnock, and Lake Macquarie LGA’s. The Newcastle and Maitland LGA’s contained very little priority habitat and may therefore act as a barrier to koala movements in between population(s) in the Port Stephens LGA and Cessnock / Lake Macquarie LGA’s.

A range of key threatening processes for the koala within the Lower Hunter study area were identified including (but not limited to): loss, fragmentation and degradation of habitat both at a fine and large scale; barriers to habitat connectivity (including natural and manmade structures); road fatalities; predation by dogs; disease (Chlamydia and other diseases); fire (including both control burns and natural fire); climate change; and groundwater abstraction (where it impacts on koala habitat).

Conserving patches of greater than 100 ha with koala feed and roosting tree species; and seeking to incorporate connectivity between patches for koalas; were considered to be high priority conservation areas for koalas.

As a result of this study, it is recommended that:

 Outcomes of this study should be incorporated into regional and local conservation planning in the Lower Hunter.

 Ongoing refinement of the model should be carried out as more specific or relevant information becomes available. This may include review by an expert working group, refinement of criteria weightings and the inclusion of newer or more targeted data sets as they become available (particularly updated regional vegetation classification).

 Testing of modelled habitat value should be undertaken prior to its adoption into local and regional planning to support long-term conservation of koala populations in the Lower Hunter. For example, population genetic analysis, field based koala pellet surveys and community surveys could be conducted.

 High priority conservation areas outlined in this study that are located outside of existing protected areas (such as National Parks) should be considered for long-term protection.

 Regional and local conservation planning should consider protecting existing connectivity and enhancing connectivity of koala habitat patches that are within 100m of another patch.

 Regional and local conservation planning should consider management of threats to koalas, including dogs, barriers to movement (road/rail), fire, disease and climate change.

 Ideally, monitoring of outcomes for koala populations should be undertaken. It is noted that this would require substantial resources due to the cryptic nature of the koala. However, given the recognisable nature of the koala and the public interest in this species, engagement with the community and key stakeholders may provide a qualitative form of monitoring through some (or all) of the region, though it is noted that this would not provide quantitative data on population size or change, which would require more formalised scientific formal studies.

 Koala research findings, and potential application of mitigation measures, should feed back into koala recovery planning processes as part of an adaptive management framework. Such a framework should include community, stakeholder and expert engagement.

1 Introduction

1.1 CONTEXT The Lower Hunter Koala Study was commissioned by the Department of Sustainability Environment, Water, Population and Communities (SEWPaC) under the Sustainable Regional Development program (the program). The program facilitates regional sustainability planning that will lead to a strategic assessment of future urban development and associated infrastructure in the Lower Hunter region. This study is designed to address a key information gap for the strategic assessment.

1.2 STUDY BRIEF This study is designed to collate existing knowledge of koala populations, habitat areas and conservation requirements across the study area in order to inform conservation planning for the Koala in the Lower Hunter. The Lower Hunter study area is made up of the Newcastle, Lake Macquarie, Cessnock, Maitland and Port Stephens Local Government Areas (Figure 1). It is acknowledged that this study is one part of effective, long term koala conservation that will require a combination of good land use planning, active species management and mitigation actions. This, in turn, will need a collective effort from multiple stakeholders, guided by the Koala Recovery planning framework.

Figure 1: Lower Hunter study area The driver for this study is the regional sustainability planning process and accordingly it poses a series of structured questions:

• What is the current population number of koalas in the Lower Hunter region? • What is the rate of change in this population and has this rate changed? What are the major and minor causes behind this? • What is the current extent and quality of koala habitat in the region? • What criteria should be used to identify high priority habitat areas? • What are the local key threatening processes and recommended conservation measures for koalas to assist with decision making for the Lower Hunter Regional Strategy and Regional Conservation Plan? The parameters of this study were to make use of existing data available in the public domain to inform the conservation planning needs of koala in the Lower Hunter and identify priority research areas that could be considered for future funding. Therefore, this study does not include any new field surveys for the Koala.

The intention of the project is to collate all of the known available records and koala knowledge in the region to inform predictive habitat mapping, population estimates and trends and prioritise areas for conservation consideration. The study methods use predictive, spatial modelling informed by point records and known koala habitat requirements in combination with local expert knowledge. Point records are largely sourced from the NSW Wildlife Atlas and are therefore assumed to be a combination of systematic survey as well as opportunistic or ad hoc observations.

The results of the predictive habitat maps and koala population information may be used to inform conservation land planning decisions at a regional scale. This regional scale perspective can assist strategic planners in prioritising areas for further research where more refined information is required and can assist in protecting high priority koala habitat areas.

2 Methods

2.1 OVERVIEW This study applied a systematic approach to building a knowledge base on Lower Hunter koalas to inform the planning recommendations. The process comprised the following steps;

Review existing available literature, spatial data audit including contextual landscape Step 1 information

Stakeholder and expert consultation to draw on local knowledge and more broadly on species expertise and conservation planning experience

Step 2 Stakeholder and expert knowledge of historical variations in koala numbers and trends in rate of decline and habitat dynamics form an essential information source for this study in light of the paucity of population studies across the whole study area

Develop key criteria to define and map all koala habitat in the Lower Hunter Step 3 Develop criteria to identify high priority habitat areas

Step 4 Data analysis and spatial modelling undertaken in a geographic information system (GIS)

Step 5 Analysis of results

Report key recommendations regarding conservation and threats to Koala to support Step 6 regional planning and management in the Lower Hunter region

Peer review by independent expert (Dr Tim Curran, Department of Ecology, Faculty of Step 7 Agriculture and Life Sciences, Lincoln University, NZ)

2.2 EXISTING KNOWLEDGE OF KOALA POPULATIONS AND HABITAT IN THE LOWER HUNTER In order to collate and build on existing knowledge of koala in the Lower Hunter, this study included a broad literature and data search of library resources, planning reports, council studies, carer group records and academic studies. The literature and data search had two specific goals;

1. to obtain as much information as possible on known records and habitat for koalas in the study area; and

2. to draw on research findings from other areas that may be applied to inform the study methods or recommendations.

SEWPaC had previously conducted a wide literature search on general koala ecology and requirements as part of the EPBC koala referral policy development.

The literature search included over 210 documents ranging from scientific research papers to koala plans of management and policy documents. A synopsis of key findings that are relevant to this study is included in this report.

There is a substantial information base on koalas in the Port Stephens area that has contributed to this study. In addition, there are local area studies in parts of Cessnock and Lake Macquarie local government areas, as well as a number of development related studies across the study area. However, the geographically disparate nature of this data is a key challenge for this study addressing regional koala protection.

2.3 STAKEHOLDER CONSULTATION As part of this study a wide group of local, regional, state and federal stakeholders were informed of the study process and invited to contribute through provision of species information, spatial data or information on related planning initiatives. An initial letter of introduction from SEWPaC was distributed to an agreed list of stakeholders by email and follow up phone calls made to interview key stakeholders.

Following is summary of initial responses from the stakeholder groups.

State Government Agencies:

 Department of Planning nominated a watching brief on project outcomes.  NSW Office of Environment and Heritage participated through the provision of data, koala expertise and regional planning expertise.

Local Government:

 Newcastle, Maitland and Cessnock Councils chose to take a watching brief and be informed of study outcomes.  Port Stephens and Lake Macquarie Council were able to provide expertise and data to inform this study.  Hunter Councils Environment Division was able to provide data through SEWPaC’s Environmental Resource Information Network (ERIN).

Non-government koala organisations:

 Wildlife carer groups were represented by the Hunter Koala Preservation Society (HKPS) and the Native Animal Trust Fund (NATF) and both provided community data and expertise.  The Australian Koala Foundation provided information regarding Koalas in the Medowie area (Port Stephens LGA).

Following the initial stakeholder consultation, 17 koala and local experts were invited to attend a workshop to discuss the koala habitat conservation requirements in the study area, of whom 13 were able to participate. The workshop was held 19th February 2013 in Newcastle, NSW. The outcomes of the workshop have been used to guide the mapping methods and conservation recommendations.

2.4 KOALA HABITAT MODELLING The Study identified criteria for priority koala habitat across the Lower Hunter by applying a systematic, expert-driven spatial model using the best available data using geographic information system tools. These criteria were discussed at the expert workshop and the expert-driven model was nominated as the best representation of environmental data with varying sources of uncertainty.

The discussion and definition of the criteria for the model was informed by previous koala modelling methods that have been applied in the Lower Hunter (see Table 1); other model research results; and

© ECO LOGICAL AUSTRALIA P T Y L T D 6 Lower Hunter Koala Study most importantly, on the outcomes of the expert discussions at the workshop regarding local habitat requirements and data limitations to predict koala habitat in the study area.

Table 1: Key predictors of Koala Habitat in models derived from broad-scale environmentally stratified surveys (Cork et al. 2000b).

Details of survey and analysis Study Location Key predictors of koala habitat Data Analysis Gentle topography, high proportion of NSW National adjacent areas cleared, low probability of dry sclerophyll on site, low to moderate Parks and Northeast NSW Generalised moisture index, deep soil, moderate 932 presences rainfall (1500-2500mm), moderate Wildlife Service (79,000 km2) additive modelling disturbance low ruggedness, south or (1994) north latitude within study area

Low elevation, wet sclerophyll forest with Canonical dense understory, greater probability of Kavanagh et al. Northeast NSW 40 presences, 251 occurrence in previously logged than correspondence unlogged forest, easterly longitude, few (1995) (15,000 km2) absences analysis hollow trees

Model 1: low foliar phenolics, increasing probability of occurrence with years since fire Model 2: low (<1000mm ) or high Cork et al. Northeast NSW 31 presences, 515 Generalised linear (>1500mm) rainfall, increasing probability of occurrence with years since fire, (1997) (26,000 km2) absences modelling intermediate to high ratio of eucalypts to other tree species, increasing probability of occurrence with increasing annual daily mean temperature of 10-180 C

Within Port Stephens, the most important determinant of the probability of koala presence, averaged across the landscape, is the distribution of primary/ secondary habitat, with anthropogenic factors such as road density and dog ownership of secondary importance (Rhodes et al. 2006). This study has found the predicted probability of koala presence increased with amount of primary /secondary habitat; and the predicted probability of koala presence decreased as road density increased (Rhodes et al. 2006). Therefore, this study has mapped potential candidate habitat areas based on ecological suitability and then constrained that footprint by measures of patch distance and road density (grid based).

Expert discussions to drive the model definition at the workshop included the identification of appropriate data types for the model and relevant data sources; as well as a definition of methods and the criteria for specific use of the data within the context of the Lower Hunter. A summary of the following inputs and criteria for the model includes:

 Feed trees (preferred / supplementary)  Soil landscape (high soil fertility)  Vegetation types  Proximity to water  Large patch sizes not intersected by major infrastructure  Recorded koala sightings  Linear barriers defined as major roads and railway corridors.

The model is based on numerous vegetation map inputs, with the Greater Hunter Vegetation Mapping (version 4) as the base where more detailed vegetation mapping data was not available. There are a number of variations in vegetation classification across each of the (five) vegetation mapping products used. However, a rudimentary study area wide map of proportional abundance (limited to a high moderate or low rating) of preferred primary, secondary and supplementary tree species within a vegetation classification unit was able to be compiled from the various inputs based on supporting information available for each of the mapping products used.

Figure 2 shows the conceptual pathway recommended as an outcome of the workshop. A brief explanation of each model variable is provided in Table 2.

Koala Habitat Value

Patch size

Vegetation type Soil Types Proximity to water Infrastructure GHM v4 modified (Base layer)

rd Lake Macquarie (Bell & Port Stephens 50m buffer to creeks (3 Fertile soil selection Major roads Major rail Driscoll v5) Composite vegetation order +) + intersect with map 2011 preferred vegetation types

Cessnock Kurri Kurri Literature & previous Yengo (DECC 2008b) (Bell & Driscoll) studies

Documented preferred Point Records (prior to 94 soil types intersect Output tree species 1985, post 1986) with point records Derived input

Raw input

Assign presence (or Analysis / Treatment proportional abundance) rating to vegetation type

Figure 2: Spatial model pathway to map potential koala habitat in the Lower Hunter

Table 2: Model Inputs

Preferred Tree Species

Primary & Secondary feed tree species Description Supplementary tree species used for shelter (temperature/weather), roosting, dispersal List of species distilled from

Sources - Previous studies (published reports) - Expert knowledge - Analysis of GIS intersect of koala records and vegetation types (GHM v4)

Selection of vegetation types known to have preferred koala tree species (of all categories)

Usage The proportional abundance of specific tree species in a vegetation community type was assigned to map polygon (where available), however, these statistics are usually an average representation of composite species and on-ground composition will vary among stands.

Most koala habitat models are based on reports of the tree species that koalas use for food and shelter. The general consensus of these models is that koalas use few eucalypt species intensively at any given site but often use other eucalypts and some non-eucalypts less intensively (Cork et al. 2000b).

Tree species that are known to be preferred by koalas for food occur in the study area (Matthews et al. 2007, Phillips et al. 2000, Curtin & Lunney 1995). However, koalas do Rationale not feed equally on all “food” tree species. Individual tree selection, or palatability, is thought to be context-dependent and influenced by nutrient foliar levels and leaf moisture content (Moore et al. 2010, Moore and Foley 2005).

In addition, koalas are known to use a variety of other tree species for shelter and roosting (Ellis et al. 1995, Matthews et al. 2007). Recent studies indicate feed tree selection may be mediated by temperature and time of day (Ellis et al 2009, Crowther 2012).

Point Records of Koala

Description Compiled koala records

- NSW Wildlife Atlas including o 1986/87 statewide survey (Reed et al 1989) o Yengo community survey 1995 (Curtin & Lunney 1995) o NSW public survey 2006 (Lunney et al 2009) o State Forest records Sources - Lake Macquarie Council records - Port Stephens Council records - Carer Records including o Hunter Koala Preservation Society & o Native Animal Trust Fund

Data accuracy – - 1000 m accuracy is adequate due to movement potential of Koalas - 10,000 m accuracy is inadequate Usage Date of Records - - 0 = no record; - 1 = prior to 1985; - 2 = 1986 to current Known occurrence indicates habitat use at a point in time and provides a geographic coordinate for habitat (or movements), irrespective of quality. The records inform general distribution irrespective of tenure; however, they do not reflect distribution limits. The dataset is considered opportunistic rather than systematic across the whole study area; however, the perceived geographic bias in the dataset is untested. Records may be intersected with model variables to determine candidate areas of Rationale suitable habitat. This approach does not map koala abundance or site occupancy (Cork et al 2000). Expert knowledge is applied in addition to point records to determine koala habitat patterns in the Lower Hunter. Workshop discussions recommended one date filter (1985) be applied to capture all records from the 1986/87 statewide koala survey. SEWPaC are currently consulting on 3 draft date categories (pre 1990, 1990-2000 and post 2000). These 3 categories could unnecessarily exclude point records from analysis and were not recommended for the LH Study by the workshop.

Vegetation Map

Description Native, extant vegetation distribution (1:25,000)

- Whole Study area base layer = GHM v4 - Fine scale mapping o Lake Macquarie (Bell & Driscoll v5) Sources o Port Stephens (composite map 2011) o Cessnock . Yengo and Parr (DECC 2008b) . Kurri Kurri (Bell & Driscoll 2010) Select vegetation types known to contain preferred koala tree species, and analyse Usage percentage cover as a function of high, medium or low of preferred tree species where data permits and assign primary, secondary or supplementary attribution. Vegetation maps are used in conjunction with other environmental variables to identify suitable habitat in large study areas that require predictive modelling approaches rather than systematic field surveys. Rationale Vegetation type has been established as a major predictor in identifying suitable koala habitat in previous studies (Phillips et al. 1996, Matthews et al. 2007, Moore et al. 2010)

Soil Types

Description Soil Landscape Maps

- Soil Landscapes of the Gosford-Lake Macquarie 1:100,000 Sheets (Murphy Sources 1993) - Soil Landscapes of the Newcastle 1:100,000 Sheet (Matthei 1995)

- Soil Landscapes of the Port Stephens 1:100,000 Sheet (Murphy 1995) Select fertile soil types based on: - Intersect of koala point records (94 candidate soil types) - Published tree preferences on identified soil types Usage o Aeolian And Swamp soil landscapes of Quaternary origin o soil landscapes derived from Nerong and Paterson Volcanics o alluvial deposits of Quaternary and Permian origin (Phillips & Callaghan 1996) The use of feed trees by Koalas is directly related to foliar nutrient levels which are a Rationale function of soil fertility (Moore et al. 2010, Moore and Foley 2005, Phillips & Callaghan 1996).

Proximity to Water

Description Distance to water dependent vegetation

- Land and Property Information (Topographical) Drainage Maps Sources - Bureau of Meteorology NSW Groundwater Atlas

rd Usage Buffer creek lines (3 order steams and above) with 50m buffer. Include candidate habitat areas where buffer intersects preferred vegetation types. Feed tree species selection research indicates moisture content influences koala tree selection (Moore et al. 2010). Leaf moisture content cannot be generated for this study, however, leaf moisture is assumed to be proportionally greater where reliable surface or groundwater source is nearby. Rationale In addition, riparian koala habitat is considered high affinity, high density capacity habitat (Ellis et al. 2010). Access to freshwater resources for drinking, especially as drought refuge is important for long term koala conservation in variable climatic conditions.

Infrastructure

Description Presence of major infrastructure or density of minor infrastructure

- GHM v4 major roads layer Sources - Land and Property Information Infrastructure Maps

- Major barrier roads (speed limit) & rail split remnant vegetation into 2 patches o F3 Freeway o Richardson Road, o Lemon Tree Passage Road, o Usage Nelsons Bay Road, o Port Stephens Drive, o Gan Gan Road o Rail corridors – north/south & east/west - Other roads and infrastructure barriers that may reduce koala habitat quality have been incorporated into the vegetation patch size indicator.

Major roads and railway deemed to be barriers between patches even though individual Rationale koalas will cross them (at risk of death/injury).

Patch Size

Description Area of native, extant vegetation in remnant patches greater than 100m apart

Sources Vegetation extent and infrastructure data as above

Usage Patch size and context e.g. road density and other barriers used to inform habitat categorisation.

Rationale The expert workshop noted that koalas can cross greater distances than 100m; however, this increases vulnerability during crossing.

3 Results

3.1 KOALA ECOLOGY Koalas are largely solitary animals, however they are not territorial and individual home ranges may overlap (SEWPaC 2012). The size of koala home ranges varies throughout the species distribution, likely due to quality, structure and connectivity of habitat. The expert workshop found that a home range of 10ha is expected to be suitable for supporting a few individuals in high quality habitat in the Port Stephens area; however, one individual koala was known to live within a 2 ha home range within Port Stephens after being forced out of its original home range due to fire. Koala populations in Yengo National Park in the Cessnock local government area are reported to have an estimated 80ha home range due to low quality habitat (Curtin and Lunney 1995). A dominant male’s home range usually overlaps with those of several females, to which he maintains access during the breeding season (Cork et al. 2000a & b).

The physiology of the Koala reflects its low nutrient diet and the need to conserve energy. Their rate of metabolism and therefore their energy and nutrient requirements are half that of the average mammal (Cork et al. 2000a & b). Koalas may spend up to 20 hours a day resting and sleeping, being most active around early morning, dusk and during the night, in order to conserve water and energy (Van Dyck and Strahan 2008; Kavanagh and Stanton 2012). This need to conserve energy may make Koalas more vulnerable to disturbances that reduce the ability of food or increase foraging effort (Cork et al. 2000b).

Koalas weigh 4–14 kg and can live for 15+ years in the wild based on unpublished results from tagged koalas at Campbelltown (Robert Close pers. comm). The koala’s oestrous cycle is 27–30 days, and pregnancy generally lasts between 34 and 36 days (Cork et al. 2000a). Females give birth to a single infant weighing about 0.5 g and 2 cm long in the warmer months of, on average, 2 out of each 3 years (Cork et al. 2000a). Young koalas are weaned by 12 months but may remain associated with the mother for another 11 months.

Tree use and diet choice by koalas have previously been linked, with varying degrees of support, to tree size and species (Moore et al. 2010). More specifically, this relates to concentrations of nitrogen, phosphorous, potassium, fibre, volatile terpenes, soluble sugars, and moisture within leaves (Moore et al. 2010). Koalas have also been found to visit trees less frequently that contain high foliar concentrations of deterrent plant secondary metabolites known as formulated phloroglucinol compounds (Moore and Foley 2005). There can be variation in the palatability of browse within the same species, and this combined with the spatial context with regards to surrounding trees affects koala tree selection choices (Moore et al. 2010).

Koalas may also change diet and select different tree species throughout the year to reflect increased energy requirements in winter and increased water requirements in summer (Ellis et al. 1995). Although suitable feed trees are often thought to be the primary factor in koala distribution, the presence of large shady trees used for diurnal shelter may also be important in some areas or during extremes of temperature (Ellis et al. 1995, Ward 2002). Several non-food trees in the Port Stephens LGA are used during the day (including Angophora costata, Eucalyptus signata and Corymbia. gummifera) and selected taller trees were used more intensively during summer suggesting their use as shelter (Matthews et al. 2007).

Koalas feed disproportionately on a small number of tree species in relation to the total number of eucalyptus species across the koala’s distribution. These species vary according to location and between different koala populations. The use of feed trees by Koalas in the Port Stephens LGA is directly related to soil fertility. The main geomorphological units preferred by Koalas are Aeolian and Swamp soil landscapes of Quaternary origin. These soil landscapes derive from Nerong and Paterson Volcanics and Transferral and alluvial deposits of Quaternary and Permian origin (Phillips and Callaghan 1996).

3.2 HISTORICAL DISTRIBUTION IN THE LOWER HUNTER Koalas were previously widespread in eastern Australia and an intensive hunting industry developed following an increase in population density in some regions during the late 1800s. However by 1910 the industry had collapsed due to a shortage of Koalas (Meltzer et al. 2000).

The landscape of the Lower Hunter has been dramatically altered over the past 200 years. This has resulted in considerable loss and fragmentation of koala habitat and the inevitable reduction in abundance and distribution of koalas (Knott et al. 1998; Kavanagh et al. 2007; Crowther et al. 2009).

An estimated 75% reduction in Koala habitat has occurred within Port Stephens LGA since European settlement of the area (Knott et al. 1998). As early as 1900 Koalas are thought to have disappeared from several areas in the Lower Hunter Region such as; Maitland, Morpeth, Bolwarra, Phoenix Park, Woodville, Wallalong, Miller’s Forest, Nelson’s Plains and Hinton (Knott et al. 1998). These areas are now extensively cleared for agriculture and expanding urbanisation.

Estimates suggest that as much as 80% of the secondary Koala habitat categories and between 40- 60% of the remaining areas of primary habitat within the Port Stephens LGA are no longer utilised by koalas (Phillips et al. 1996). Historical estimates of population size suggest well below 1000 individuals distributed over the entire Port Stephens study area and likely between 350-500 animals in total, though it is noted that this population estimate was noted as being “speculative but considered” (Phillips et al. 1996).

Lunney et al. (2007) undertook population viability analysis for a 7,000 ha study area within Tomago Sandbeds in the Port Stephens LGA, of which approximately 4,000 ha was considered to be koala habitat, bounded by Grahamstown Lake to the north, Fullerton Cove to the south, Siddons Swamp to the west and Majors Flat to the east. This study assumed a starting population of 800 individuals based on extrapolations from intense searches undertaken to rescue live and record dead koalas after fires from 1994 – 1998.

3.3 PRESENT POPULATION DISTRIBUTION Port Stephens LGA has a significant Koala population (PSC 2002); however, the Hunter Koala Preservation Society noted at the expert workshop that in some areas the numbers are declining. An indication of recorded koala sightings can be seen in Figure 3, below.

Koalas generally prefer vegetation on fertile soils and within the Hunter-Central Rivers CMA this is true at higher elevations, whereas at low elevations koalas occupy less fertile soils. This dichotomy reflects the nature of the extensively cleared landscape of the Hunter Valley, with development dominating the

© ECO LOGICAL AUSTRALIA P T Y L T D 15 Lower Hunter Koala Study valley floors. Significant areas of preferred koala food trees only remain at higher elevations or on sandy and less agriculturally productive soils at lower elevations (Crowther, McAlpine et al. 2009).

Anecdotal Evidence

Anecdotal reports from long term residents, carers (including data from the Native Animal Trust Fund (NATF)) and ecologists can provide an insight into population trends and local population responses. Anecdotal reports can be a valuable information source in the absence of systematic data on population trends. In some cases the anecdotal reports can trigger research projects with a data collection component.

Anecdotal observations were discussed in the workshop and the following comments were made:

 Ray & Anne Williams used to frequently record koala sightings in their back yard in the Medowie area. They have noticed a decline in the frequency of their observations and now don’t find any.

 Geoff Bartlett noted that Raymond Terrace used to have high koala activity, but this is no longer the case.

 Audrey Kooseman and local volunteers conducted koala searches at Tomarree Sandbeds following bushfires and found no animals or evidence of koala activity. This suggests the former population was depleted, relocated or eradicated.

 It is noted that other anecdotal observations may be available, but was outside of the scope of this project

Figure 3: Recorded koala sightings (source: NSW Wildlife Atlas; Lake Macquarie & Port Stephens Council Records; NATF & HKPS carer records)

3.4 TREE SPECIES A list of potential koala tree species was generated from a literature review (Callaghan et al. 1994, Australian Koala Foundation 1996, Phillips et al. 2000, Port Stephens Council 2002, Biolink 2006, DECC 2008), and presented to the expert workshop for ranking as to primary, secondary, and supplementary koala tree species (see Appendix A for results and definition of koala tree species terminology).

There are some instances where the group withheld input due to lack of data and supporting knowledge. It was proposed to use the highest category of tree usage where more than one level is attributed. It is noted that this approach is conservative and may possibly over predict koala habitat. Some specific considerations included:

 Eucalyptus camfieldii has been used in the Tomago sand mined area that has been opened up by road construction. The workshop noted koalas are probably opportunistic to new habitats depending on drivers for dispersal.

 Feed trees in close proximity to threats (e.g. wild dogs or major roads) may not constitute preferred habitat. However, there may be options to mitigate the impact by incorporating management measures such exclusion fencing for major roads combined with facilities such as underpasses and/or overpasses.

Whilst recent literature emphasises the role of supplementary tree species for other habitat needs other than food, it is not known if there has been any systematic research whether koalas can survive in areas without supplementary (roost) trees. The expert group concluded that koalas would adapt usage of trees for shelter to the species available to them to complement preferred feed tree species. The use of Callitris pine and ironbark species as shelter trees was noted by the expert group.

The workshop discussions also noted:

 Most of the available information was from the eastern Port Stephens area; whilst there were knowledge limitations across Cessnock, Maitland, Newcastle and Lake Macquarie areas.

 Koalas in urban areas can use different species (i.e. planted species like E. nicholii) than those in native woodland areas. This study focuses on existing mapped areas of native vegetation.

 E. parramattensis is an important species. Although Tomago Sands area is highly cleared (mining / fire), E. parramattensis is still used by Koalas in the area and will eventually regrow to provide important rehabilitated habitat. E. parramattensis potentially occurs in large areas of Lake Macquarie City Council area, but only a small area is known within the Morisset area. E. Parramattensis subsp decadens is also a co-dominant canopy species in the Kurri Sand Swamp Woodland EEC, which occurs near Kurri Kurri in the Cessnock LGA.

3.5 HABITAT MODELLING The conceptual model pathway recommended by the workshop and literature review was used to source and prepare a number of relevant spatial data sets and compile the expert driven model identifying koala habitat across the landscape of the Lower Hunter. The spatial modelling was carried out using GIS analysis as an expert driven model which combined all the spatial datasets into a single dataset depicting relative value for koala habitat across the landscape of the Lower Hunter.

The components of the spatial data model or multi-criteria analysis are presented below in Table 3. The process included the development of appropriate scoring and weighting for each recommended data variable identified through the workshop process. The multi-criteria analysis process of combining specific, agreed data sets is a recognised technique, identified as suitable for complex decisions which involve the comparison of decision elements which can be difficult to quantify; and ranks and prioritises values using decision analysis tools to summarise comparisons of the items importance (Saaty 1980; Crossman et al. 2009; Mendoza and Macoun 1999).

The ranking and weightings associated with each data set were derived based on discussions of the relative importance for each of the data sources with relevant experts and through the literature review. This process was based on a Delphi technique (Linstone & Turoff 1975) to rank and prioritise the variables. The rationale for each variable criterion is defined in Table 2.

The analysis was then carried out using GIS to combine all the spatial datasets into a single dataset. The base score derived for each data set was normalised (between 0 and 100) in order for data set scores to be measured with the same numerical scale and eliminate any numerical bias in the calculation (Zeiler 1999).

All scores for each dataset were spatially maintained as separate attributes within the derived dataset. An interim weighting was applied to the two data sets representing feed trees preferred by koalas, depending on whether they were representing vegetation types containing primary or secondary feed tree species.

Table 3: Data preparation, scores and weighting