The Potential of Fossil Mammal Middens as Indicators of Vegetation History in Central Australia

The plant macrofossil contents of two fossil mammal middens were investigated. Midden MS was collected from near Mt Swan, 200 km north-east of Alice Springs in central Australia. The vegetation in this region is predominantly grassland scattered with low trees. Midden KS was collected from Kathleen Springs, 240 km west-south-west of Alice Springs. The flora in this locality is dominated by forbs and chenopods. Midden KS had a radiocarbon age of 1700 years BP at the top and 3500 years BP at the bottom. Most of the plant taxa in each midden were components in the flora of the vegetation zones currently surrounding that midden. However, the two middens, collected from different vegetation zones, shared only 33% of taxa. Similarly, only 24% of species were common to the July 1987 vegetation at the two localities. A vertical slice of midden KS was cut into 25 subsamples. No progressive change of subsample plant macrofossil assemblage with depth could be detected by Principal Components Analysis. However, there was a weak tendency for subsamples from the same level in the midden to be similar. It was concluded that mammal middens are potentially useful indicators of the vegetation history of central Australia.