History of the Leadbeater’s Possum

Leadbeater’s possum evolved about 20 million years ago. There is no known documentation of Leadbeater’s Possum by the indigenous people’s of Victoria. It was first documented in 1867 and was originally known only through five specimens, the last one collected in 1909. From that time on, the fear that it might be extinct gradually grew into near-certainty after the swamps and wetlands around Bass River in south-west Gippsland were drained for agriculture in the early 1900s. By the time of the devastating 1939 Black Friday fires, the species was thought to have been extinct.

On 3 April 1961, a member of the species was rediscovered by naturalist Eric Wilkinson in the forests near Cambarville, and the first specimen in more than 50 years was captured later in the month. At this time a colony was discovered near Marysville. Extensive searches since then have found the existing population in Victoria’s Central Highlands. However, the availability of suitable habitat is critical: forest must be neither too old nor too young, with conservation efforts for Leadbeater’s possum involving protection of remaining old-growth stands, and maintenance of younger stands that are allowed to attain hollow-bearing age.

The combination of 40-year-old regrowth (for food) and large dead trees left still standing after the fires (for shelter and nesting) allowed the Leadbeater’s possum population to expand to an estimated peak of about 7500 in the early 1980s. From its peak in the 1980s, the Leadbeater’s possum population was expected to further decline rapidly, by as much as 90%, due to a habitat bottleneck. The population has dropped sharply since 1996. Particularly, the February 2009 Black Saturday bushfires destroyed 43% of Leadbeater’s possums habitat in the Central Highlands, halving the wild population to 1,500. A study in 2014 concluded there is a 92% chance the Leadbeater’s ecosystem in the Victoria central highlands will collapse within 50 years.