The highland Leadbeater’s possum, a critically endangered cold-adapted species restricted to a small area of forest in south-eastern Australia, is at risk of extinction due to bushfire, native forest logging, and climate change. Recent captive-breeding efforts have proven challenging, and there are few in situ management options available to mitigate the increasingly severe impacts of climate change and bushfire. Assisted colonisation to expand the area of occupancy may provide the best avenue to spread the risk posed by these threats and reduce extinction probability.
We undertook expert elicitation to examine the likelihood of ≥500 individuals remaining in the wild in 50 years under three management scenarios (1) conservation action within the species' current range to address short-term threats (i.e. provision of artificial dens to address current tree hollow shortages), (2) establish a satellite insurance population to reduce the risk of fire- and climate-driven extinction in the medium- to long-term, and (3) a combination of these. Multiple release regions within Victoria were compared, with varying combinations of carrying capacity, fire risk, future climate suitability, and alignment with the species' historic range. The best population outcomes were estimated to occur when applying both den provisioning in the species' current range and establishing a satellite insurance population in two distinct regions.
Assisted colonisation of Leadbeater’s possum has political risk, whereby it could be used as an argument to continue logging within the species' current range; a potentially perverse outcome that must be avoided.