Leadbeater's Possum - History

History

The possum was not discovered until 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 in Australia around Bass River in south-west Gippsland were drained for farming in the early 1900s. Then, on 3 April 1961, a member of the species was rediscovered by naturalist Eric Wilkinson, and the first specimen in more than 50 years was captured later in the month.

In 1965, a colony was discovered near Marysville. Extensive searches since then have found the existing population in the 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.

A formerly fairly healthy population was ascribed to the terrible Black Friday fires that swept through Australia in 1939: 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 (since declining to 2000 prior to the Black Saturday fires, and possibly to 100 since). However, the old trees were gradually decaying and the regrowth maturing.

From its peak in the 1980s, the Leadbeater's possum population is expected to further decline rapidly, by as much as 90%, due to a habitat bottleneck. The population has dropped sharply since 1996. Failing human intervention, and assuming that a reduced population could have survived that long, natural tree hollows were expected to develop in the Black Friday regrowth as the trees reached about 150 years of age in the second half of the 21st century, and numbers to begin climbing again.

The status of Leadbeater's possum is in even more doubt following the disastrous bushfires that swept its only known habitat on Black Saturday in February 2009 - large areas of bushland around Marysville, Narbethong and Healesville have been destroyed,.