LATE QUATERNARY ENVIRONMENTAL-CHANGE AND HUMAN IMPACT AROUND LAKE BOLAC, WESTERN VICTORIA, AUSTRALIA

The late Quaternary history of the Lake Bolac region is reconstructed from sedimentary and pollen analysis of lake and swamp sequences and i s supported by archaeological remains from lunette sediments. Freshwat er deposits recovered from lake Turangmoroke appear to date from the l ast glacial period, when the vegetation was composed of herbfield and grassland. Subsequent dry conditions at the end of the Pleistocene cau sed the deflation of some accumulated sediments. On refilling, the lak e had become saline. As moisture availability increased, casuarina woo dland, dominated by Allocasuarina verticillata, became the regional ve getation cover. Domination by casuarina ended ca. 8000-7000 yr BP, pro bably as a result of rising saline ground-water tables. Casuarinas wer e replaced to some degree by eucalypts, augmented by the development o f a riverine Eucalyptus camaldulensis woodland. Swamp deposition comme nced in the channel of neighbouring Fiery Creek at ca. 4000 yr BP, mos t likely as the result of a reduction in stream flow with decreased pr ecipitation. Despite suggestions of significant impact on the vegetati on by Aboriginal people from other sites in southeastern Australia, th ere is no evidence of any alteration here from periods of occupation d ated to around 13000 yr BP and after 3500 yr BP. The period of Europea n occupation, though, is marked by significant changes in fire pattern s, reduced tree cover, loss of floristic diversity, increased erosion rates and salinity levels, and decreased water levels.