The role of coastlines, people and fire in the development of heathlands in northeast Tasmania

Abstract

Pollen analysis of a core taken from a reed marsh in northeastern Tasmania near Bass Strait highlights the interplay between climatic changes, sea level rises and the effects of Aborigines during the Holocene. Prior to 10,000 bp the region formed part of the Bassian landbridge which connected Tasmania to the Australian mainland. Vegetation at that time was characterized by shrubby grasslands with a very sparse tree cover. After 9000 bp, Eucalyptus forests prospered until about 6000 bp. A combination of salt spray from a stabilizing mid-Holocene coast, the progressive effects of soil podsolization and burning by Aborigines, eventually favoured the replacement of grassy Eucalyptus forests by Allocasuarina with an increasingly heathy understorey. The treeless heaths dominated by dwarfed Allocasuarina which presently dominate the area are regarded as part of a degradation sequence in which the above factors are implicated.