Multifaceted genetic analysis of the "Critically Endangered" brush-tailed rock-wallaby Petrogale penicillata in Victoria, Australia: implications for management

Abstract

The use of molecular genetic techniques can aidwildlife managers in setting priorities anddevising management strategies for scatteredpopulations of threatened taxa. In this study,six remnant populations of the “criticallyendangered” brush-tailed rock-wallaby (Petrogale penicillata) in Victoria, Australia,were examined using karyotypic, microsatellite(11 loci) and mitochondrial DNA (mtDNA) controlregion sequence analysis. Each remnantpopulation was found to be genetically distinct(unique microsatellite alleles and controlregion haplotypes), but had low geneticdiversity. This distribution of geneticdiversity between, rather than withinpopulations, is most likely a consequence ofrecent severe reductions in population size anddispersal that have occurred since Europeansettlement. The six mtDNA control regionhaplotypes identified in the Victorianpopulations were all closely related (average1.3% sequence divergence), and only 2%divergence separated haplotypes from EastGippsland and the Grampians (550 km to thewest). In contrast there was considerablesequence divergence (7.7%) between theVictorian haplotypes and those found in P.penicillata from elsewhere in the speciesrange. In comparison, 8.8% divergenceseparates P. penicillata from the closelyrelated P. herberti. The Victorianhaplotypes also formed a distinct and wellsupported monophyletic group that excludedhaplotypes from other P. penicillata andP. herberti. In light of these data, werecommend that the remnant Victorianpopulations of P. penicillata be managedseparately from remaining populations in NewSouth Wales and Queensland; and thatindividuals be regularly exchanged amongst theVictorian populations to increase theirdiversity and reduce the likelihood ofinbreeding depression.