The distribution and roost habitat of the orange leaf-nosed bat, Rhinonicteris aurantius, in the Pilbara region of Western Australia

Abstract

The endemic orange leaf-nosed bat, Rhinonicteris aurantius, is a relict both in a phylogenetic and a geographic sense. Prior to this study, two colonies in disused mines and seven other records of single animals were known from the disjunct Pilbara population of Western Australia. Cave roosts were located in the region for the first time, five new roosts were found in disused mines and the species was recorded in five new localities. Cave roosts were discovered in sandstone bedding. Free-flying R. aurantius were located in a diverse range of landscapes composed of banded iron formation, Cleaverville Formation geology and granite. Mines utilised as roosts were structurally complex and in some cases breached the watertable. This study revealed that while the species is widespread throughout the region, it is restricted to certain landform units, the number of suitable roosts within landform units is limited and the population appears to be subdivided within the region. Dispersal and connectivity within the population may be dependent on the availability of roosts in intervening areas, which may be a function of the availability of groundwater to subterranean formations for the control of roost microclimate. Currently, the known breeding range is one gorge at Barlee Range Nature Reserve and one mine at Bamboo Creek.