About the species
The Brush-tailed Rock-wallaby (BTRW) is a small wallaby with adults weighing approximately 5-8 kg. They are generally brown with grey shoulders, a reddish-brown rump and short dark feet. The tail is long (normally longer than their body length), dark, thick and ends in a brushy tip. They have a white cheek stripe and a black dorsal stripe from the eyes to the back of the head.
These animals can be found in a variety of habitats from rainforest to open woodland and are extremely agile animals. They dwell in very rock terrain such as along rocky escarpments and in boulder piles and rocky outcrops. They require numerous crevices, subterranean passageways, ledges and overhangs for shelter and safety. They prefer north facing sites as they sun themselves in the morning and afternoon.
Rock-wallabies are difficult to spot because of their camouflaged nature and the terrain in which they live. Often the best evidence of their presence is their droppings which are easy to identify. These are cylindrical in shape with a small point at one end.
They feed on a wide variety of grasses as well as small herbs, leaves, flowers, fruits and bark.
Distribution and status
The species has a range from Queensland to Victoria, roughly following the line of the Great Divide. In NSW the Shoalhaven is the southerly most population and the Warrumbungle Ranges is the westerly. There has been a decline in numbers and a reduction in range. In southern NSW and in Victoria they are now highly fragmented, with small isolated populations dotted across the former range. Brush-tailed Rock-wallabies are listed as Endangered in NSW, Critically Endangered in Victoria and Vulnerable in Queensland. Recovery Plans have been developed for both the NSW and VIC animals to assist in species management and recovery.
The NSW BTRW Recovery Plan lists the following key threatening processes:
- Predation by foxes, dogs and cats
- Competition for habitat and food with goats and rabbits
- Habitat degradation by clearing, human disturbance and weed invasion
- Diseases including toxoplasmosis spread by cats
- Bioclimatic factors
- Weed invasion
- Elevated fire frequencies
Predation by foxes has most often been cited as the primary threat to BTRW, as detailed in the NSW Fox Threat Abatement Plan.
The Shoalhaven Brush-tailed Rock-wallaby Protection Program
The South Coast Region of the NSW National Parks and Wildlife Service (NPWS) began the Shoalhaven Brush-tailed Rock-wallaby Protection Program in 1995. The species was listed as Vulnerable at the time and known to be in decline throughout much of its range. A survey of rock-wallaby distribution in parts of southern New South Wales in 1995 identified the Kangaroo Valley area as an important stronghold for rock-wallabies in southern NSW. It was recommended that a 1080 fox baiting program be instigated in order to reduce predation pressure on the rock-wallabies and aid rock-wallaby survival and population growth. This program was commenced in the Kangaroo Valley area in 1995. At this time it was estimated that there were between 30 to 60 rock-wallabies remaining in the Shoalhaven.
In the Kangaroo Valley area rock-wallaby colonies are located primarily on private property. This provided the opportunity for the community to become involved in rock-wallaby management in the Shoalhaven. NPWS encouraged landholders to conduct 1080 fox baiting on their land with NPWS supplying equipment, training and supervision. Where landholders were supportive but not interested in conducting their own baiting, NPWS sought permission to conduct baiting for them. NPWS also began fox baiting on NPWS estate in the area as well as Crown Land and Sydney Catchment Authority land.
In June 1998 the rock-wallaby program received joint funding from Environment Australia with a similar Brush-tailed Rock-wallaby program in the Hunter Valley region. The funding continued through to March 2001. A major aim of this joint program was to determine the effect of 1080 fox control on both the fox and rock-wallaby populations. Consistent monitoring of the fox and rock-wallaby populations in the baited area (Kangaroo Valley) and in an adjacent unbaited area (Illaroo) commenced in June 1998.
The results of the surveying efforts indicate that between 1998 and 2001 the abundance of rock-wallabies in the baited colonies declined at a significantly slower rate and fox numbers were significantly lower compared to those in the unbaited area. It is possible that the reduced fox densities in the baited area resulted in the slower decline of rock-wallaby numbers in this area. Nevertheless, rock-wallaby numbers in the baited area still declined and greater efforts to reduce fox numbers were considered necessary to ensure their survival. As a result, the baiting strategy was reviewed in 2001 with the aim of improving the effectiveness of fox control. Following the review, a number of private properties (where fox baiting was expected to dramatically improve colony protection) were targeted for inclusion in the baiting program. Fox baiting was also extended to the Illarro area (previously the unbaited site) in April 2002.
In 2001 the NSW Fox Threat Abatement Plan (Fox TAP) was produced to addresses the impact of predation by the Red Fox on threatened species. This plan identified Brush-tailed Rock-wallabies as one of a suite of threatened species most likely to be impacted by fox predation and thus a high priority for the assistance of fox control. The Plan also identified the Shoalhaven area as one of a dozen priority sites in NSW. The Shoalhaven BTRW Protection program continues today as one of the Fox TAP funded sites with regular fox baiting and fox/rock-wallaby monitoring works. Our results are being compared with the results gained from the other Fox TAP priority sites across the state.