Late holocene human impact on two coastal environments in New South Wales, Australia: a comparison of Aboriginal and European impacts

There are few historical analyses quantifying impacts of human activity in Australia. This paper compares vegetation change, fire regime, erosion and eutrophication rates between the European period and the recent prehistoric past in two lake systems on the south coast of New South Wales. The variance in pollen abundance and hence species population changes increased markedly in the historical period, especially amongst understorey taxa, and this could be related to changes in the local fire regimes and to the effects of grazing. Local fire activity decreased from the prehistorical period at both sites. Erosion rates increased in the historical period and both organic and inorganic components were deposited in the lakes. Erosion episodes could be related to fire during some periods but are clearly controlled by forest disturbance and land-use at other periods. The trophic status of the lakes was increasing from before European settlement but accelerated in the recent past. This was in part due to the increased erosion rates and in part due to fertiliser application. The results suggest that lower rates of erosional and eutrophic change occur in catchments with basaltic than with Holocene sand substrata.