Holocene Vegetation and Environments Near Goulburn, New South Wales

Abstract

Three sites from Breadalbane Basin and one from Wet Lagoon near Goulburn were studied to provide a history of vegetation, fire and lake levels in the region. Stratigraphy, a percentage pollen diagram from each site, an influx diagram from two sites and 29 radiocarbon analyses provided the basic data and chronology of the study. The sedimentary history shows that Breadalbane Basin has undergone several cycles of lake phases with sediment accumulation and dry phases with deflation of the lake sediments. The present lake clays and silts of Breadalbane Basin and Wet Lagoon are all Holocene in age. A lake began forming in Breadalbane Basin before 9300 B.P. and probably reached its greatest extent between 7400 and 2700 B.P. At Wet Lagoon water stands were in evidence from 5000 B.P. Over the last 2000 years the sites have dried out and are ephemeral swamps but their water level histories are not necessarily synchronous.

A comparison of the records shows that the vegetation of the region has been open eucalypt woodland with understorey dominated by grasses and herbaceous taxa. The most dramatic change was woodland clearance after the arrival of European settlers. The spread of pollen and charcoal collection sites, however, emphasizes a number of local differences in the vegetation of the region. Casuarina, for example, expanded during the mid Holocene along the escarpment on the western side of Breadalbane Basin. The charcoal input curves show fire was a frequent occurrence in the region but the vegetation was apparently resilient to its effects until European settlers used it as a tool in woodland clearance.