The burning question 323 17 The burning question: Claims and counter claims on the origin and extent of buttongrass moorland (blanket moor) in southwest Tasmania during the present glacial-interglacial Mike Macphail Department of Archaeology and Natural History, Research School of Pacific and Asian Studies, Australian National University, Canberra
[email protected] Introduction Claims and counter claims about the origins of the buttongrass moorland (blanket moor) in southwest Tasmania explicitly or implicitly are founded on the ‘ecological drift’ concept formulated more than 40 years ago by the late Professor W.D. (Bill) Jackson, at the University of Tasmania. Ecological surveys and modelling experiments have provided much valuable information about the dynamic balance between the plant associations forming buttongrass moorland under present-day climates, soil types and fire regimes. However, thus far, fossil pollen provides the only direct evidence about the origins, geographic extent and long-term directions of change in buttongrass moorland in the prehistoric past. For example, fossil pollen demonstrates that the eponymous species of buttongrass moorland, Gymnoschoenus sphaerocephalus, was present in the Last Glacial vegetation in southern Tasmania during the late Last Glacial period and provides the first compelling evidence that buttongrass moorland may have been continuously present in the Lake Pedder area of southwest Tasmania throughout the Holocene period. This paper compares various models proposed over the past 40 years to account for the development of buttongrass moorland across southwest Tasmania since the Last Glacial period. How well, and on what time scales, the directions and magnitude of changes predicted by the various models are supported by the palaeoecological evidence is important to understanding the climate-vegetation-fire linkages in present-day buttongrass moorland.