Prioritizing regions to conserve a specialist folivore: considering probability of occurrence, food resources, and climate change
Adams-Hosking, C, McAlpine, CA, Rhodes, JR, Moss, PT & Grantham, HS 2015, Conservation Letters, vol. 8, no. 3, pp. 162-170.
This study identified the implications of a changing climate for koala populations across eastern Australia, predicting changes in distribution for both the koala and its preferred food trees. Such information is integral in informing conservation decisions; in particular, the recognition of priority areas for planning efforts. Under a ‘business as usual’ climate model, priority areas for conservation were shown to shift significantly, in most cases outside of the species’ existing range.
By combining current distribution models for the koala and its preferred food trees, separate conservation prioritisation models were developed under four climate scenarios. Additionally, under each climate projection, the probability of koala distributions overlapping with their key food trees was determined, where greater overlap was considered to be of higher conservation significance. Connectivity of available habitat was also assessed. A cost metric was incorporated into the model as a means of examining the socioeconomic validity of planning decisions. For all scenarios, it was demonstrated that priority areas for conservation shifted further eastward, clustering along the edge of the koala’s existing range. When only assessing changes to koala distribution under future climate change, priority areas were shown to shrink towards the coast, where there exists increased water availability. However, when incorporating food tree distribution, priority areas remained further westward, inland from the coast. All scenarios experienced a threshold effect, whereby a reduction in koala and food tree distributions occurred after 60% of the landscape was removed.
Given the extent of urbanisation across Australia’s east coast, the identification of priority areas further inland is advantageous for conservation planning; providing cost-effective options that are unlikely to be impacted by further development. The priority status of such areas indicates the occurrence of preferred food trees – information that can be incorporated at the local planning level for strategic activities such as revegetation and small-scale protection. Moreover, planning decisions which recognise changes in the distribution of both koalas and key food trees are more likely to give rise to reliable, wiser investments. Apart from high-value agricultural land, cost did not significantly affect the selection of priority areas. Further local and regional-scale analysis of land value/use is required to assess the socioeconomic viability of planning decisions.
Considering both food and habitat requirements, findings indicate a shift of high priority areas outside of the koala’s existing distribution, presenting significant challenges for conservation. To appropriately manage climate change impacts, planning must be scaled down to a level at which decisions can be made in local political, economic and social contexts.
Summarised by Julian Radford-Smith
Disclaimer: The summary of this report is provided for reference purposes only and does not represent the findings or opinions contained in the original report. Although every effort has been made to bring forward the main elements of the report, this review is no substitute for the full the report itself. Should you have any concerns or perceive any errors please contact us and we shall endeavour to rectify and improve the review.