Collections in space and time: geographical patterning of native frogs, mammals and reptiles through a continental gradient

Abstract

Native frog, mammal and reptile specimen data in the Western Australian Museum were examined from the western third of the Australian continent covering nearly 22 degrees of latitude and 16 degrees of longitude and encompassing tropical, desert and temperate regions. The timing of specimen data collection and collecting effort were evaluated and show that large areas of the State remain poorly sampled. The great majority of the collections have been made over the last 50 years and taxonomic status of many vertebrate species is still in review with several new species being described. Systematic surveys need to be undertaken to address the inadequacy of information on vertebrate fauna distributions over large tracts of the desert and pastoral areas of Western Australia. The distribution of taxa endemic to Western Australia, threatened and priority taxa as well as restricted?range endemic taxa were examined over equal areas based on the 1 :250 000 map series that covers the western third of the Australian continent. Endemic taxa are focused in the south-west of the state and along the west coast, while restricted-range endemics are more frequently distriooted along the west and northwestern coasts. Threatened and priority taxa show a similar pattern to that of endemic taxa. The similarity of areas across Western Australia, based on the composition of their vertebrate fauna, indicates that there are four broad regions corresponding to the tropical north, the mesic south-west, the semi-arid southwestern interior and the arid Pilbara and desert areas. Additionally, regional areas defined under the IBRA scheme were examined for the number of sampling locations, endemic taxa in the various fauna! groups and the richness of taxa recorded. The Pilbara bioregion, one of the best-sampled areas of the State, showed limited concordance between vertebrate taxa similarity in half-degree cells and subregional boundaries and relatively high heterogeneity in vertebrate fauna distribution across the bioregion.