A Critically Endangered Emblem
The Leadbeater's Possum (Gymnobelideus leadbeateri) is a small, fast-moving marsupial exclusively found in the forests of Victoria. It is the state's official faunal emblem, a title it received in 1971. This possum has a body length of about 15 centimeters with a distinctive club-shaped tail of a similar length. Its survival is tied to a very specific habitat: the montane ash forests of the Central Highlands. These forests are dominated by Mountain Ash (Eucalyptus regnans), the tallest flowering plant on Earth.
The possum's entire existence depends on tree hollows. It is a social animal, living in small colonies of up to 12 individuals, which nest together inside the cavities of large, old trees. These hollows, however, do not form overnight. Mountain Ash trees generally need to be at least 150 to 200 years old before they begin to develop cavities suitable for a possum colony to take residence. The possums construct elaborate nests inside these hollows using shredded bark.
For decades, the Leadbeater's Possum was thought to be entirely extinct. First described scientifically in 1867, the last confirmed specimen was collected in 1909. After 50 years with no sightings, it was declared extinct in 1960. The scientific community was stunned when, on April 3, 1961, naturalist Eric Wilkinson rediscovered a small population near Marysville, in the very Central Highlands forests they are known from today.
A Housing Market Collapse
The primary threats to the Leadbeater's Possum are habitat destruction from logging and fire. Extensive timber harvesting in the Central Highlands targets the very Mountain Ash forests the possums rely on, removing the old, hollow-bearing trees for their survival. A single colony defends a territory of about 2-3 hectares and requires multiple hollow-bearing trees within that small range.
Fire poses an equally devastating threat. The 2009 Black Saturday bushfires were catastrophic for the species, burning through approximately 45% of its habitat. The possum population was estimated to have been halved by this single event. These fires kill the large, old trees that provide nesting sites. Subsequent salvage logging operations can then remove even the fire-killed trees that could have provided temporary shelter, further degrading the habitat.
This combination of factors has led to the species being listed as Critically Endangered. Conservation efforts include the installation of wooden and plastic nest boxes to provide artificial homes while waiting for new trees to mature. This is a temporary measure, as the long-term survival of the species depends on the protection of existing old-growth forests and allowing younger forests to reach an age where they can naturally form hollows.