A Review of the Conservation Status of Koalas In
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A Review of the Conservation Status of the Queensland population of the Koala ( Phascolarctos cinereus ) leading up to and including the 2019 fire events. A Report Prepared for World Wildlife Fund (WWF) Australia March 2020 Biolink koala conservation review Table of Contents 1. EXECUTIVE SUMMARY ................................................................................... 3 2. INTRODUCTION ................................................................................................. 6 3. DESCRIPTION OF THE QLD POPULATION ................................................... 6 Current distribution .................................................................................................... 6 Size of QLD koala population ................................................................................... 8 Queensland Areas of Regional Koala Significance (QARKS) .................................. 8 Methods – Queensland Areas of Regional Koala Significance ............................. 9 Results – Queensland Areas of Regional Koala Significance ............................... 9 4. INFORMING CHANGES TO POPULATION ESTIMATES ............................ 14 Wildnet / ALA Records, Published Reports and Areas of Occupancy .................... 16 Methods – Wildnet and ALA Records .................................................................. 16 Methods – Available reports ................................................................................ 16 Methods – Area of Occupancy (AoO) analysis ................................................... 17 Results – Wildnet and ALA records .................................................................... 18 The 2019 Fire Events ............................................................................................... 23 Methods ................................................................................................................ 23 Results .................................................................................................................. 23 Areas experiencing decline in the most recent koala generation ............................. 27 5. ONGOING NATURE OF PRIMARY THREATS ............................................. 28 Climate Change .................................................................................................... 28 Land Clearing ....................................................................................................... 29 Other considerations ............................................................................................ 30 Limitations and Qualifications ..................................................................................... 30 6. CONCLUSION .................................................................................................... 32 Appendix A .................................................................................................................. 38 Appendix B .................................................................................................................. 41 Appendix C .................................................................................................................. 42 Citation: Wallis, K., Lane, A. and Phillips, S. 2020. A review of the conservation status of Queensland populations of the Koala (Phascolarctos cinereus) arising from events leading up to and including the 2019/20 fire event . Report to World Wildlife Fund (WWF) Australia. Biolink Ecological Consultants, Uki NSW. 2 Biolink koala conservation review 1. EXECUTIVE SUMMARY In the context of broader population trends across Queensland, this report initially set out to objectively quantify the impacts of recent fire events on Queensland koalas during the Spring and early Summer of 2019. Our baseline estimate for the number of koalas in Queensland was informed by recently published data derived from a process of expert elicitation that provided population estimates for relevant Interim Biogeographic Regionalisation of Australia (IBRA) areas within Queensland. However, instead of a focus on numbers per se , this review focuses instead on estimated proportional changes brought about by the fire events, while also giving consideration to other changes occurring over the preceding three koala generations (18 years); this was done in order to place the results in the appropriate International Union for the Conservation of Nature (IUCN) conservation criteria considerations. Koala population increase, decrease or stability within each bioregion was initially assessed via interrogation of Wildnet and Atlas of Living Australia records, with further consideration given to government and peer-reviewed reports and / or publications. The scarcity of detailed and systematic surveys of koala distribution and abundance over extensive parts of Queensland necessitated an independent bioregion-by-bioregion assessment of changes to the key range parameter Area of Occupancy ; it was also necessary to establish where the majority of regionally significant koala source populations were located across the state, a matter we approached using the methodology developed by other workers to identify Areas of Regional Koala Significance (ARKS) in New South Wales. Once delineated, these areas (herein referred to Queensland Areas of Regional Koala Significance - QARKS) were considered further by examining changes in records and reporting rates across both inside and outside of QARKS. The preceding process identified what appears to be the functional extinction of koalas from the Mitchell Grass Downs bioregion, as well as substantive declines in all other bioregions except the Einasleigh Uplands and Wet Tropics combined bioregion. Most notable amongst these was an estimated 80% decline across the Mulga Lands in the states south-west, which was previously considered to support the second highest proportion of koalas across all bioregions in Queensland. The estimated proportional decline of the Queensland koala population over the preceding three koala generations, but prior to the 2019 fire events, was thus conservatively estimated as a pre-existing 48.95% reduction in population size. 3 Biolink koala conservation review Following on from the above, spatial data on the geographic extent of fire grounds burnt over the period from August – December 2019 were intersected with bioregion and QARKS boundaries. Within these areas we used what we consider to be a conservative mortality estimate of 70%, based partly on information from individuals surveying some of the fire grounds, all of whom reported extreme intensity crown fires. Six of the eight combined bioregions examined in this study, namely Einasleigh Uplands and Wet Tropics, Southeast Queensland, South Brigalow, Central Mackay Coast, Brigalow Belt North and Desert Uplands were variously impacted by fires up to December 2019. The combined Einasleigh Uplands and Wet Tropics bioregions were the most affected with 6.68% of the entire land surface burnt. It is estimated that the largest proportion (33.04%) of koalas killed in the 2019 fire events resided in the Einsleigh Uplands and Wet Tropic bioregions. This mortality equates to a 0.28% loss to the Queensland population, the highest of any bioregion. Southeast Queensland and Brigalow Belt North bioregions were the next two largest contributors to koala mortality from the fire events, contributing 25.32% and 24.52% to the total loss respectively. Two QARKS, Magnetic Island (Brigalow Belt North) and Clumbe (Southeast Queensland), each had more than 25% of their total surface area burnt. Applying a deductive approach qualified by uncertainty regarding variation in carrying capacity across individual QARKS, we estimate the 2019 fire events removed a total of 1.66% of the remaining Queensland koala population once previous losses had been accounted for. Communicating this latter outcome in terms of koala numbers, if the estimated numbers of koalas occurring in Queensland are correct, it implies that a minimum of 672 koalas were killed by fire across the state between August and December 2019. We consider that our calculations on the matter of population change and the impacts of the 2019 fire events to be conservative and should be considered as a minimum effect. Based on this consideration, we conclude that the Queensland koala population has declined by at least 49.80% over the three most recent koala generations, inclusive of the impacts of the fire events up until December 2019. The factors driving these circumstances for koalas are ongoing, and there remain other factors which have not yet been taken into account but which will otherwise increase the estimated minimum effect. Hence any prognosis regarding the future conservation status of the species must adopt a precautionary approach. For these reasons, we consider that the species readily meets the criteria of endangered under Queensland’s Nature Conservation Act 1992 as having “… undergone a large reduction in 4 Biolink koala conservation review numbers” (Part 5, Division 2, section 78A), as well as satisfying IUCN criteria for endangered; that being a loss of ≥ 50% of the population using criterion A conservation considerations. 5 Biolink koala conservation review 2. INTRODUCTION This report has been prepared on behalf of the World Wildlife Fund (WWF) Australia. Koalas have experienced declines over large parts of their range in eastern Australia, with Queensland (QLD) populations considered to be experiencing the greatest losses (Adams- Hosking