This study assesses human impact on the landscape around Cobrico, a volcanic crater lake in dairying country in south‐western Victoria. It compares the last 150 years of impact of European settlement against approximately the previous 1500 years of prehistoric occupation and land use. Focus is on vegetation dynamics, erosion, productivity changes and the fire regime. Since European settlement there has been woodland clearance and recovery, the introduction of many plant and animal species and a significant increase in the intensity in the fire regime. While many direct linkages are apparent between environmental variables some operate over significant time lags. Fire has played a major role in vegetation dynamics and has favoured open ground taxa at the expense of Eucalyptus and Melaleuca. While major fires do not always lead to erosion in the catchment it is clear that some changes in the chemistry of erosion products have resulted, with potassium and iron showing increases in the historic period.