Holocene vegetation,fire and environmental history of the Discovery Bay region,south-western Victoria

The results of pollen, sedimentary and charcoal analyses of four cores and three peat profiles are presented. Casuarina woodland dominated the dryland vegetation over at least the past 6000 years, with a Melaleuca lanceolata-composite scrub association on the dunes. There is no evidence of higher sea levels in the area in the past 6000 years, with the present freshwater backdune swamp and lake systems being maintained or expanded. After a period of regional dune building between about 6000 and 4000 years BP, dune mobilization and advance in the last 4000 years or so overrode seaward brackish and fresh swamp systems. This dune advance severed Long Swamp from the Glenelg River estuary and precipitated the development of freshwater swamp conditions there. Burning of the swamp surface, often associated with the presence of Typha, is evident in a number of peat samples and is probably primarily anthropogenic. Continuous low-level burning occurred throughout the dryland vegetation of the region but is not associated with any long-term or widespread vegetation change. None of the environmental changes identified require a purely climatic explanation, and all have relevance for discussions of the regional prehistory.