A survey design for monitoring the abundance of arboreal marsupials in the Central Highlands of Victoria

We describe a non-standard sample design for monitoring the abundance of arboreal marsupials in the montane ash forests of the Central Highlands of Victoria, south-eastern Australia. The survey design is based on overlapping and rotating sampling from a given population of sites—in this case 160 sites, each measuring 1 ha in size. Estimates of population sizes are obtained using a model-based statistical analysis. Results so far reveal considerable year-to-year variability in populations of Leadbeaterʹs Possum (Gymnobelideus leadbeateri), the Mountain Brushtail Possum (Trichosurus cunninghamii), and the Greater Glider (Petauroides volans). There appears to be an initial decline in the numbers of Leadbeaterʹs Possum, an increase in the Mountain Brushtail Possum and no change in the Greater Glider and the total number of arboreal marsupials. It will be possible report more substantive findings about long-term trends after several more years of the program. Relationships between current and past counts for Leadbeaterʹs Possum and Mountain Brushtail Possum were very weak. This result appeared to be due to low levels of site fidelity for these two species.