The emergence of an agricultural landscape in the highlands of New Guinea

That pollen and sedimentological evidence can make a significant contribution to our understanding of the nature and antiquity of agricultural development in the highlands of New Guinea has long been recognised and promoted by Jack Golson. Detecting the beginnings of agriculture and subsequent impact on landscape and vegetation is, however, not straightforward. A conceptual model for the identification of human impact in palaeoecological records is constructed to distinguish between the impact of hunter-gatherer and agricultural activity. Five palaeoecological sites from highland valleys (1400-1890 m altitude) that cover the period from the last glacial maximum (22 000 cal BP) to the present are reviewed and the implications of the rate and direction of environmental changes are evaluated. Using Rate of Change analysis as a means of identifying deviations in the rate of vegetation change from that which would be expected under natural climate change, the earliest indications of agricultural impact in the vegetation record can be identified at around 7800 cal BP. Subsequent vegetation change reflects an increase in anthropogenic impact that is punctuated by peak episodes of vegetation change towards a more open landscape. The emergence of an agricultural landscape in New Guinea is seen as a result of gradual indigenous development punctuated by external influences such as introduced domestic plants and climate change and variability.