Holocene variability in semi-arid vegetation: new evidence from Leporillus middens from the Flinders Ranges,South Australia

Twenty-seven Leporillus spp. (stick-nest rat) middens provide palaeoecological evidence with good spatial coverage across the northern and central Flinders Ranges, South Australia, for three Holocene time slices: 7-5 ka. 4-2 ka and < I ka. Plant macrofossils and faecal pellets from middens were AMS radiocarbon dated, and pollen and plant macrofossils were used to reconstruct vegetation histories. Woodland anid shrubland comnmunities with herbaceous understoreys were dominant around 7-5 ka in the northern ranges, and shrublands with an understorey of herbaceous taxa and chenopods were dominant in the central ranges. Warmer, wetter and more homogenieous conditions than present are indicated during this period. Shrubland communities declined in the central ranges during the period 4-2 ka with increasing aridity, to be replaced by chenopod shrublands with a less diverse component of herbaceous taxa in the understorey. Chenopod shrublands continued to increase from 1 ka to present in the central ranges. In the more sheltered topography of the northern ranges, shrublands persisted from 4-2 ka, and some woodland and shrublands remain through to present. Present spatial variability in the vegetation is a feature of the last thousand years or so (possibly longer in the central ranges), compared with less variability in the early to mid-Holocene.