Extensive gene flow in a threatened bat (Rhinonicteris aurantia) in an arid landscape

Abstract

The bat fauna of Australia comprises some 25% of all terrestrial species, yet we know very little of the demography, dispersal, and movement dynamics of most bat species. The Pilbara leaf-nosed bat ( Rhinonicteris aurantia Pilbara form) is a threatened microbat that roosts exclusively in caves that occur in mineral rich deposits in the Pilbara region. Due to their specific roost microclimate requirements these bats cannot survive for long without a suitable roost and are sensitive to roost disturbance. Understanding the connectivity of roosts throughout the Pilbara is crucial for informed decisions to mitigate potential impacts to persistence of this species in areas under economic development. Along with mitochondrial DNA (mtDNA) markers, we used reduced representation genomic sequencing of over 150 individuals from eight roost sites throughout the Pilbara and tested for landscape-scale population differentiation associated with the two major subregions — the Hamersley and Chichester, as well as finer-scale among roost variation. We found evidence of high rates of dispersal and low population structure within the Pilbara, indicating one panmictic population, with mtDNA results suggesting evidence of some female philopatry. Our results highlight the ongoing need for detailed genetic studies to provide critical insight to species dispersal, particularly in multi-use landscapes. We discuss the importance of identifying and retaining connectivity of key habitat to maintain genetic diversity and gene flow throughout panmictic populations.