Identification of a remnant population of the black-flanked rock-wallaby (Petrogale lateralis lateralis) in Kalbarri National Park, Western Australia, and implications for its management

Abstract

Black-flanked rock-wallabies (Petrogale lateralis lateralis) were thought to be locally extinct in Kalbarri National Park, Western Australia, until 2015 when a pair were photographed in the Murchison River gorge. Subsequent searches failed to locate any other populations and, in combination with previous surveys, suggest that these animals were the sole survivors of a formerly abundant population. Efforts to capture the rock-wallabies to obtain tissue samples and ascertain their genetic affinities were unsuccessful. However, fresh faecal material was collected and a ~600-bp fragment of DNA sequence data was obtained from a mitochondrial DNA gene. The Kalbarri rock-wallabies were found to be genetically distinct from all other sampled populations of P. l. lateralis. They were genetically most similar to rock-wallabies in the Calvert Range, 950km to the north-east in the Little Sandy Desert. Nearer populations in Cape Range (600km north) and the Western Australian Wheatbelt (500km south-east) were less closely related. Following evaluation of a variety of factors, including population size, genetics, demography, ecology, environment and logistics, a decision was made to supplement the Kalbarri National Park population with females sourced from the Western Australian Wheatbelt. In May 2016 three females were released at the same site as the Kalbarri pair to try to ensure the survival of the population whilst still preserving unique Kalbarri alleles.