DOI: 10.18195/issn.0313-122x.78(1).2010.185-204 Records of the Western Australian Museum, Supplement 78: 185–204 (2010). Patterns in the composition of ground-dwelling spider communities in the Pilbara bioregion, Western Australia Bradley J. Durrant1, Mark S. Harvey2, 4, Volker W. Framenau2, 4, Ricardo Ott2, 3 and Julianne M. Waldock2 1Department of Environment and Conservation, PO Box 51, Wanneroo, Western Australia 6946, Australia. Email:
[email protected] 2Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia. 3Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul, Rua Dr. Salvador França, 1427, 90690-000, Porto Alegre, Rio Grande do Sul, Brazil. 4School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia. Abstract – Ground-dwelling spiders were sampled at 304 quadrats in 24 survey areas chosen to represent the geographical extent and diversity of terrestrial environments in the Pilbara region of Western Australia, an area of approximately 179,000 km2. Only taxa that were primarily ground-dwelling and were taxonomically robust were identifi ed to species level. A total of 375 species comprising 14 families was recorded. The families Salticidae (93 species), Zodariidae (71 species) and Oonopidae (70 species) showed marked species-level radiation. After excluding quadrats that were burnt or fl ooded during the sampling period, the distribution data of 375 species from 294 quadrats were analysed, with an average of 12.9 (SD = 6.8) species per quadrat. Singletons (species recorded at only one quadrat) constituted 26% (98 species) of the total number of species, and were found more frequently in the Roebourne and Fortescue subregions.