The Brush-tailed Rock-wallaby (Petrogale penicillata) no longer exists in the wild in the ACT, but the ACT Government is running a captive breeding program that may lead to its eventual reintroduction to ACT and interstate reserves.
This medium-sized wallaby appears to have become extinct in the Canberra region only in the last few decades. Declared endangered in the ACT in 1996, it is also declared vulnerable nationally and in NSW and Queensland, threatened in Victoria, and near threatened by the International Union for Conservation of Nature.
Once common and widespread in the mountainous country of south-eastern Australia, from southern Queensland to the Grampians in Victoria, the wallaby’s natural range has been reduced to the north-eastern part of its range. Captive animals may be seen at Tidbinbilla Nature Reserve. Introduced populations are present in western Victoria, Hawaii and New Zealand.
The Brush-tailed Rock-wallaby is one of 16 known rock-wallaby species. Its distinctive dark tail is usually longer than its head and body combined and has a conspicuous brush at the tip. Its strong muscular hind quarters and patterned soles make it well-adapted to living in rugged terrain.
They live in rocky areas that have abundant ledges, caves and passageways where they can bask in the northerly sun but hide when feeling threatened. They graze on nearby grass, forbs and herbs.
Between four and ten closely-related females will usually live together with a single male. Each female has about ten offspring during her eight year reproductive period.
Many factors have contributed to the demise of Brush-tailed Rock-wallabies, which require rocky terrain with suitable foraging habitat nearby.
Indiscriminate hunting for the commercial fur trade in the late 1800s and early 1900s caused huge damage to the population, reducing colony numbers significantly. Remaining colonies became vulnerable to other threatening processes. Introduced pests such as red foxes, which kill wallabies for food, and rabbits and goats, which compete for food, further reduced the populations.
Loss of so many colonies of wallabies fragmented their habitat, leaving isolated populations vulnerable, particularly during droughts and wild fires. In the ACT, changes to former habitat and in the recreational use of preferred habitat areas may be obstacles to successful reintroduction of the wallaby.
Since 1999, research in the ACT on captive populations has increased understanding of the ecology and management of the Brush-tailed Rock-wallaby and helped state and national recovery efforts.
The captive breeding program at Tidbinbilla Nature Reserve has bred animals for reintroduction in Victoria and NSW. The ACT Government provides expertise in the ecology and management of the species based on physiological, behavioural and reproductive biology studies of the Tidbinbilla population.
The ACT Government now intends to investigate the suitability of possible reintroduction sites within the ACT and the feasibility of re-establishing wild populations that can be maintained at low cost forever. However, before a species can be successfully re-introduced to an area, the factors that caused the initial loss must be dealt with. Effective, long-term predator control will be fundamental to any re-introduction program. Once initiated, predator control will need to be sustained indefinitely.