Warrumbungles Brush-Tailed Rock- Wallabies and the Fox Impact
by Javier Guiance

Brush-tailed Rock-wallaby Photo Max Herford

The Brush-tailed Rock-wallabies (Petrogale penicillata) of the Warrumbungle National Park currently exist within this western-most confine of the species’ range. The unique dilemma of Warrumbungle varieties’ isolation amongst the other two genetically different groups of Brush-tailed Rock-wallabies makes its population concern a major implication not only for its existing biodiversity, but also for the genus P. penicillata in general.

Controlling foxes to save the wallabies

The crucial factor of wallaby decline in the Warrumbungle National Park is the predation by foxes. Funded by the Foundation for National Parks & Wildlife, the Department of Environment and Conservation (DEC) has taken to monitoring fox numbers within the park surrounds and the success of fox control measures.

A low frequency of bait take and tracks suggests that there are only few foxes in the park itself. Immigration into the park, however, appears to be constant, and so control becomes a continuing process of removing incoming foxes.

This study of the impact of foxes on the Brush-tailed Rock-wallabies followed a 2003 genetic survey, which also received Foundation funding. In the genetic survey, pellets were examined for controlled DNA readings for the assessment of species population size.

Fighting the impacts of isolation, foxes and drought

Results obtained from genetic analysis seem to suggest that this type of procedure is a more useful and valid method for population monitoring, and the data has already assisted management decisions for the population recovery effort.

Senior Threatened Species Officer, Todd Soderquist, of the DEC said, "The Foundation funded project has helped establish a continuing program of fox control and monitoring in the region".

The Warrumbungles are home to a struggling population of the Brush-tailed Rock-wallaby. Photo: DEC

The status of the Brush-tailed Rock-wallaby in NSW has recently been elevated from Vulnerable to Endangered in recognition of the continuing disappearance of colonies that were formerly considered secure", Todd Soderquist said.

"During the past two years of drought the habitat of the species in the Warrumbungle National Park has declined. Recent rains have brought some recovery to forage condition", he added. Survey efforts have indicated that the Warrumbungle population may have subsided during the drought, though reproduction has occurred in the interim. "The recent observation of two new youngsters at one of the Warrumbungle colony sights provides much-needed optimism for the future", said Mr Soderquist.

Working with the neighbours

Mr Soderquist asserts that the point of a recovery program is to maintain local biodiversity. "All efforts at this time are being directed into saving Brush-tailed Rock-wallabies in the Park and eventually increasing their distribution until they occupy former habitat throughout the region", he said.

Fox control as implemented by the DEC within Warrumbungle National Park has bolstered the Brush-tailed Rock-wallabies’ chances. Assistance with fox control has come via welcomed sources, according to Todd Soderquist, "The coordinated efforts of Park neighbours to reduce foxes in the surrounding private land (therefore hindering movement of foxes into the Park) has been an extremely important aspect of the program’s success".

For more information about this program see http://www.coona.net/rockwallaby/. (Close the window to return to this article.)

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