Stick-Nest Rat Middens as Sources of Paleoecological Data in Australian Deserts

Abstract

AbstractThe existing paleoenvironmental data from the Australian arid zone lack sensitivity and come from only a few sites. Macrofossils and pollen from four dated middens of the stick-nest rat (Leporillus spp.) were analyzed from two sites in Western Australia. Animal and plant macrofossil remains were well preserved and provided evidence of change in species distribution within the last 1150 yr. Brush-tail possum and golden bandicoot have contracted their ranges in the recent past, possibly since the introduction of cats into Australia. An undescribed lacewing was also a significant find. Pollen preserved in parts of the same midden and in middens from different sites indicates that records are sensitive to the composition of the local vegetation when the midden was built. Pollen spectra are quite different from playa lakes, which record largely regional vegetation. Pollen preserved in the fecal pellets, desiccated urine, and grass mat nesting material provided similar information but some differences were apparent, suggesting dietary preferences were reflected in the fecal component. The pollen record suggested a trend to less-wooded vegetation cover in central Australia between 900 and 300 yr B.P.