Forest succession and habitat management for Leadbeater's possum in the State of Victoria, Australia

Abstract

The aim of the study was to develop models which predict habitat availability for a rare and endangered marsupial, Leadbeater's possum ( Gymnobelideus leadbeateri), in space and time. Measures of forest age, structure and floristics were correlated with the density of Leadbeater's possum at 32 sites in montane ash forests of the Victorian Highlands of south-east Australia. The density of leadbeater's possum was significantly correlated with the number of trees with hollows (PNTs), the number and biomass of Acacia spp., canopy and understory closure, and forest age. Peak densities occurred in regrowth forests (15–50 years), with abundant tree hollows (greater than 6 PNTs per 3 ha), and a high biomass of acacias (20–50% of stand basal area). Leadbeater's possums also occurred at low frequencies and densities in old-growth-regrowth forest ecotones, and in mature and multi-aged forests with an understory of eucalypts and acacias. Models of trends in habitat availability predict a massive decline over the next 30 years, followed by a population bottleneck lasting until the year 2075. Survival of Leadbeater's possum during the bottleneck will depend on protection of refuge habitats, particularly patches of mature, multi-age and old-growth forest. Recovery after the bottleneck is expected to depend on the extent to which current silvicultural practices can be modified to guarantee recruitment of PNTs within timber production forests.