A possum’s cautionary tale: targeted surveys in north-eastern Victoria fail to detect Leadbeater’s possum in remnant forest within its historic range

Endemic to Victoria, the range-restricted, Critically Endangered Leadbeater’s possum (Gymnobelideus leadbeateri) historically had a much broader distribution from south-east of Melbourne, through the wet forests of eastern Victoria, and extending into New South Wales. Undetected populations of this cryptic species may persist within forested sections of this historic range, despite these landscapes having been subject to significant disturbance through clearing, logging, and bushfires. The adoption of arboreal camera trapping has permitted targeted surveys for Leadbeater’s possum to be conducted with greater efficiency and reliability. Between 2017 and 2019, we conducted arboreal camera-trapping surveys for Leadbeater’s possum in seven patches of potentially suitable habitat, that were 13–145 km outside the species’ known range in Victoria’s Central Highlands. Site selection was informed by habitat suitability modelling. The species was detected at only one of seven areas surveyed, the patch closest to the possum’s current known range (~13 km). Notable occurrences of other cryptic arboreal mammals were recorded in rarely surveyed habitat types and at high elevations (>1000 m). Despite north-eastern Victoria’s significant remnant forest cover, the apparent loss of Leadbeater’s possum from its historic range in this region provides a cautionary tale regarding declining forest condition owing to major disturbance from fire and logging.