LATE GLACIAL AND HOLOCENE VEGETATION HISTORY AT GOVERNOR BOG, KING VALLEY, WESTERN TASMANIA, AUSTRALIA

Excavation of peat and clay filling a sink hole has provided a relatively long late glacial to Holocene pollen/vegetation record for the King Valley. The record shows a change from alpine herbland, Microstrobos scrub and heath at 13 ka BP to Eucalyptus subalpine woodland. Phyllocladus-Nothofagus rainforest succeeded after 12.5 ka BP but degenerated to scrub rainforest after 11 ka BP, when Lagarostrobos franklinii expanded. The sequence of local changes occurred while the sink-hole lake was being rapidly infilled and converted to topogenous peat around 12 ka BP. Examination of the timing of changes in vegetation associations in other pollen profiles from different altitudes in western Tasmania indicates that many of the changes are non-synchronous and cannot be related directly to climatic events. They probably reflect the effects of both biological and local environmental factors. The major regional climatic change from alpine to temperate conditions on the lowlands occurred ca. 13 ka BP. Demonstration of non-synchronous changes in the late glacial to early Holocene pollen/vegetation associations at several sites contrasts with the view of Markgraf et al., who infer synchronous changes related to climate. There are no indications in the pollen/vegetation sequence of either Allerod or Younger Dryas events in western Tasmania.