Population monitoring of small and declining brush-tailed rock wallaby (Petrogale penicillata) colonies at the extreme of their range using faecal DNA sampling

Abstract

Obtaining much-needed information on population parameters such as abundance and genetic diversity can be difficult for small and declining populations. The brush-tailed rock-wallaby (Petrogale penicillata) is an endangered and cryptic species with many colonies in decline. The Warrumbungle National Park (NP) in New South Wales contains a declining metapopulation of P. penicillata at the western (inland) extreme of the species’ current range. Loss of these colonies would cause substantial range contraction and probable loss of regional genetic diversity in the Central Evolutionary Significance Unit (ESU). We used non-invasive genetic methods to identify individuals from faecal DNA from five colonies in the Warrumbungle NP. We identified a minimum of 21 individuals, with the largest colony containing seven individuals. The Warrumbungle NP colonies showed significant intercolony structuring and we were able to detect a single dispersal event. Comparison of genetic diversity to other Central ESU colonies shows that loss of the Warrumbungle NP population will result in loss of unique diversity from this region. The minimum number of animals and genetic diversity information obtained in this study was used to support management actions of herbivore control and translocation in the Warrumbungle NP population.