Leadbeater’s Possum, Gymnobelideus leadbeateri

Leadbeater’s possum (Gymnobelideus leadbeateri), also known as the fairy possum, is a marsupial that can be found in a small range in Australia. It is limited to the central highlands of Victoria and prefers a habitat within forests of old growth mountain ash. The State of Victoria designated this species as its faunal emblem in 1968.

Leadbeater’s possum was discovered in 1867 and was described using five individuals collected until 1909. Because this number was low, it was thought that the species could be extinct. This was gradually accepted until 1961, when a naturalist named Eric Wilkinson discovered another individual. Another discovery was made in 1965, when a colony was found outside of Maysville. After this, extensive searches were conducted that resulted in the finding of the current population in Victoria. One population was nearly wiped out in 1939 by the Black Friday fires. These fires created a suitable habitat over 40 years for the population to increase, however, and by 1980 it numbered around 7500. In the year 2000, the Black Saturday fires decreased population numbers again to about one hundred individuals.

Leadbeater’s possum is nocturnal and is primarily arboreal, spending most of its life in the trees. It lives in familial groups of about 24 individuals, which consist of a breeding male and female, the young produced between them, and sometimes one or two unrelated males.  The members of these groups are close and will sleep together in nests constructed from shredded bark in hollow areas of trees. These nests are typically located in the center of a home range or territory comprised of 2.4 to 4.9 acres. One female usually takes the role of leading the group and will defend the territory aggressively.

This aggression is aimed towards female young after they have reached sexual maturity at fourteen months of age. This causes a greater risk of mortality for young females than young males, who are allowed to stay in the group for longer periods. Female members of this species live about twenty-seven months in the wild, but can live to be ten years of age in captivity. Individuals that do not live in groups are less likely to survive than those that do live in groups. Because of this, males tend to join foreign groups or form bachelor groups while waiting to locate a mate.

Leadbeater’s possum rests during the day and emerges from a nest during the dusk hours each day. The group will split up and begin foraging for food by leaping across branches. This species consumes a wide variety of food including saps and arthropods like spiders and crickets. Saps and other plant materials comprise about eighty percent of its entire diet, but the protein gained from arthropods is an important component to its diet.

The breeding season of Leadbeater’s possum is typically timed to allow young to be born between the months of May to June or October to November. Litters typically consist of one or two young that are born within their mother’s pouch. Young remain in the pouch for up to ninety days and will emerge from the nest about three weeks later. After leaving their birth groups, young possums can be hunted by owls.

Leadbeater’s possum is threatened by habitat loss caused by logging. Logging has occurred in protected areas, so breeding programs have been encouraged to bolster the population numbers of this species. Its current range comprises about only nineteen square miles and is thought to support a population of less than one hundred individuals. Experts have attempted to use nesting boxes to extend this species’ range and allow logging to continue, but these efforts have failed. Local and federal efforts have been conducted since the 1980’s to save this species, but its population numbers were so low before the Black Saturday fires that these conservation efforts have been difficult. More devastation occurred in 2007, when an enterprise company known as VicForests, backed by the federal government, tore down much of this species’ habitat just after more wildfires.

VicForests has been conducting salvage logging efforts since the fires, but this has also been found to negatively affect Leadbeater’s possum. This company began logging areas of forests that were untouched by fires, like the Kalatha Creek region of Toolangi in 2010. These actions were opposed by the Yarra Ranges Shire Council and even spawned legal actions taken by MyEnvironment Inc., a group that claims that VicForests did not take the proper measures to assess the viability of the area being logged before cutting down the trees.

Changes to the current legislature protecting Leadbeater’s possum have been proposed by the Baillieu State government. These changes would be made to the Code of Practice for Timber Production 2007 and would give the Secretary of the Department of Sustainability and Environment the right to exempt a logging operation from a Flora and Fauna Guarantee Action Statement. It is thought that these changes would most likely cause the extinction of Leadbeater’s possum.

Although conservationists have conducted many efforts to save Leadbeater’s possum, including education efforts, research efforts, and breeding efforts, experts believe that this species will become extinct. Des Hackett first successfully conducted breeding efforts, but in 2006, the last living individual in captivity in Australia passed away. In 2010, the last captive individual at the time, named Kasia, passed away at Toronto Zoo. In 2012, the Lake Mountain population of Leadbeater’s possum was nearly wiped out, but three individuals were captured, sparking a new hope for breeding efforts to save this species. Despite the bleak outlook for Leadbeater’s possum, it appears on the IUCN Red List with a conservation status of Endangered.

Image Caption: Gymnobelideus leadbeateri. Credit: Pengo/Wikipedia (CC BY-SA 3.0)