Human impact on the natural environment in early colonial Australia

Little Llangothlin Lagoon on the New England Tablelands of northeast New South Wales possesses the most detailed and best verified ²¹⁰Pb chronology yet available in Australia. Recent criticisms of the length of the record are shown to be based on a faulty understanding of the principles of ²¹⁰Pb dating. Attempts to revise the chronology of the lower part of the dated sequence by several decades must be rejected given that (a) fundamentally dissimilar chronological models yield ages that are statistically indistinguishable and (b) the most extreme manipulation of the modelling data fails to alter the basal dates in the profile by more than three years. The most telling criticism of the revisionist view, however, comes from the exact concordance between the dates from the basal part of the sequence, the historical date of official European contact and the massive changes in palynology, geochemistry and soil erosion resulting from that contact. The thesis that environmental disturbance immediately prior to the time of official European contact in Australia was the result of human activity is supported by a wealth of documentary evidence revealing the illegal or unsanctioned presence of Europeans throughout much of southern and eastern Australia years before official records began. Likewise, it is clear that many elements of the pre-contact Australian environment, including certain of its soils, were fragile and susceptible to rapid and dramatic disturbance under the impact of European land use. Finally, there is convincing evidence of stable chemical and mineralogical conditions in several southeast Australian lakes throughout the last millennium or more, conditions that were altered catastrophically with the arrival of the first Europeans and their stock.