Tracking and tracing central Queensland’s Macroderma – determining the size of the Mount Etna ghost bat population and potential threats

Abstract

The ghost bat, Macroderma gigas, colony at Mount Etna was at the centre of Australia’s longest-running conservation campaign. To protect the colony the Queensland Government removed recreational facilities and gated caves. The size and genetic diversity of the Mount Etna M. gigas population were estimated using cave searches, direct captures and molecular analysis to determine whether these actions have benefitted the species. In addition, telemetry was undertaken and red fox, Vulpes vulpes, scats analysed to identify possible threats. Results suggest that the population has declined by 79% since the late 1990s, has low microsatellite diversity, low effective population size (Ne) and is undergoing a population bottleneck. VHF- and GPS-collared animals were found to forage over agricultural land up to 11.8 km from their daytime roost, suggesting that poor land management and barbed-wire fences could be potential threats. No ghost bat remains were found in fox scats. We recommend that compliance be increased around Johansen’s Cave to reduce disturbance during the maternity season and landholders be encouraged to undertake management that is sympathetic to ghost bats.