Stick-nest rat middens, collected from Arltunga in the eastern Macdonald Ranges and the Palm Valley Amphitheatre of the Northern Territory, record the animals and plants that were living in the vicinity while the middens were accumulating. The middens are expected to be between 50 and 15 000 years old and can be reliably dated (Head et al 1998; Pearson et al 1999). Similar middens have provided useful palaeoecological material in North and South America, Africa and the Middle East (Betancourt et al 1990) however progress in Australia has been relatively modest (Pearson & Betancourt submitted). Preliminary analysis of middens has demonstrated that they contain significant amounts of environmental material including macrofossils of plants (Berry 1993) and animals (Pearson et al submitted). They also contain pollen and phytoliths (Allen et al 2000; McCarthy et al 1996; Pearson 1999; Pearson & Dodson 1993).
The prospective sites for midden collection were identified using GIS and local expertise. Prof Julio Betancourt, as a research visitor on the project, assisted from a bed in Alice Springs Hospital! An intensive field search preceded sub-sampling a large number of middens. Middens were sampled in the quartzite overhangs of Arltunga (n=16) and the sandstone overhangs in Palm Valley Amphitheatre (n=9).
Pollen and macrofossils in the stick-nest rat middens are used to reconstruct the plants and animals living in the area in the past. That reconstruction is compared with other fossil materials modern surveys and computer generated predictions of the environmental parameters controlling the distribution of individual taxa. The aim of these projects is to model the environmental changes that would explain the fossil record. This will assist in reconstructing past climates, and in this region the key issues are the changing behavior of the monsoon and ENSO cycles during the last 15 000 years. The information will enhance our understanding of the past plants and animals present in the arid zone and how climatic systems such as ENSO and the monsoon affect long-term vegetation dynamics.
Allen, V., Head, L., Medlin, G. & Witter, D. (2000) Palaeoecology of the Gap and Coturaundee ranges, western New South Wales, using stick-nest rat (Leporillus spp.) (Muridae) middens. Austral Ecology, 25: 333-343.
Berry, S.L., (1993) The potential of fossil middens as indicators of vegetation history in central Australia. Australian Journal of Botany 39:305-313.
Betancourt, J.L., Van Devender, T.R. & Martin, P.S. (eds) (1990) Packrat Middens: The Last 40,000 Years of Biotic Change. The University of Arizona, Tucson.
Head, L., McCarthy, L., Quade, J., Witter, D., Allen,V. & Lawson, E. (1998). Classification and radiocarbon dating of Leporillus nests in semi-arid Australia and palaeoclimatic implications. Palaeoclimates, 3: 161-177
McCarthy, L., Head, L. & Quade, J. (1996). Holocene palaeoecology of the northern Flinders Ranges, South Australia, based on stick-nest rat (Leporillus spp.) middens: a preliminary overview. Palaeogeography, Palaeoclimatology, Palaeoecology, 123: 205-218.
Pearson, S., (1999) Late Holocene Biological Records from the Middens of Stick-nest Rats in the Central Australian Arid Zone. Quaternary International, 59, 39-46.
Pearson, S., Baynes, A. & Triggs, B., submitted. The fauna identified from hair and bone in middens of stick-nest rats (Muridae: Leporillus spp.) and the accumulating agents. Wildlife Research.
Pearson, S & Betancourt, J.L., submitted. Comparison of American packrat and Australian stick-nest rat midden research: A guide to future work in Australia and other continents. Journal of Arid Environments.
Pearson, S. & Dodson, J.R. (1993) Stick-nest rat middens as sources of paleoecological data in Australian deserts. Quaternary Research, 39:347-354.
Pearson, S., Lawson, E., Head, L., McCarthy, L. and Dodson, J. (1999) The spatial and temporal patterns of Stick-nest Rat middens in Australia. Radiocarbon, 49 (3):295-308.