image: A brush-tailed rock-wallaby.
Credit: Adelaide University.
New research shows terrain complexity is an important factor when brush-tailed rock-wallabies choose habitat, providing critical insight to help bring the critically endangered species back from the brink.
Brush-tailed rock-wallaby populations have dwindled for more than a century due to historical hunting for the European fur trade and competition and predation from introduced species.
Understanding brush-tailed rock-wallaby habitat preferences allows for better decision-making when designing reintroduction and conservation programs.
“Studies suggest that reintroduction programs into open, unfenced landscapes have less than a 46 per cent success rate,” said study co-author Dr David Taggart, from Adelaide University.
“We know that the success of reintroductions is often related to effective control or exclusion of introduced predators, effective management and program organisation, environmental factors and habitat suitability at reintroduction sites.
“Our study has drawn on recent advances in modelling techniques for predicting potential species’ distributions, showing considerable potential for guiding reintroduction site selection.”
Dr Taggart and his team analysed habitat variables – rock complexity and lithology, cliff density, rainfall and water availability, vegetation cover, and elevation – and found that shelter from predators and environmental extremes was the most important factor influencing brush-tailed rock-wallaby den site selection.
“Brush-tailed rock-wallabies prefer refuge areas in complex and elevated exposed sandstone outcrops, characterised by abundant cliffs and narrow fissures that dissect rocky areas,” said Dr Taggart, whose study was published in the Australian Journal of Zoology.
There have been grave fears for the brush-tailed rock-wallaby dating back to the 1920s, when the species was feared extinct in Victoria and southern New South Wales.
“Contemporary studies have found there are only around 50-70 individuals left in Victoria, distributed across a handful of small and isolated colonies,” said Dr Taggart.
“While the fur trade no longer threatens brush-tailed rock-wallabies, the species continues to be threatened by foxes and feral cats, which kill a significant number, particularly juvenile and sub-adult cohorts.
“Wildfires also directly kill individual rock-wallabies and can lead to starvation and increase the risk of fox and cat predation due to the loss of cover.
“With the significantly low number of brush-tailed rock-wallabies remaining in the wild in Victoria and the multifaceted nature of the threats to their survival, well-informed habitat identification and selection is critical for the success of reintroduction initiatives and their long-term survival.”