Bellowing for habitat on private land: distribution of koalas in a complex landscape

Abstract Context Anthropogenic modification of landscapes through clearing, degradation and fragmentation of habitat for human land-use can cause biodiversity loss, population declines and shifts in species distributions. The koala ( Phascolarctos cinereus ) is a forest-dependent specialist-folivore with a distribution overlapping areas of high anthropogenic use. Objectives Our study aimed to identify environmental and habitat factors influencing koala distribution across a modified landscape consisting of grazing land, plantation forestry and native vegetation, and identify areas for conservation action. Methods We used Passive Acoustic Monitoring to determine koala presence at 232 sites across South Gippsland, Victoria, Australia. We examined the influence of habitat, soil, climate, topography and disturbance variables on koala occurrence. Results Koalas were present at 49% of sites. Probability of site occupancy increased with cover of preferred koala food trees at a site and total tree cover in the landscape (within 500 m), and trended towards a decline with increasing organic carbon in the soil. Over 40% of the region was predicted to have a 50% or greater probability of occupancy by koalas and 11% of the region had 75% or greater probability. Of the 11%, half was located within parks, reserves and state forest, suggesting these protected forests represent core habitat; and one third was located within plantation estate, highlighting the importance of effectively managing this tenure for koalas. Conclusions To improve outcomes for koalas in this region, we recommend promoting and facilitating revegetation on private land, which currently provides limited habitat extent. Conservation action is needed to mitigate anthropogenic land-use impacts on species distributions.