Palaeoenvironmental changes in the eastern highlands of Papua New Guinea

Abstract

AbstractA 4500 year old record of vegetation disturbance and sediment mobilisation is presented for the Arona Valley and Noreikora basin in the eastern highlands' of Papua New Guinea. Three distinct episodes of landscape change in the Arona Valley and Noreikora basin can be interpreted from the palaeoecological records: (1) by 4500 BP erosion of catchment sediments, possibly due to vegetation disturbance by human activity, led to the formation and extension of swamplands in valley bottoms; (2) after 4500 BP the newly expanded wetland environments were exploited for resources, such as Pandanus and wood, with their eventual clearance and establishment of extensive grasslands by 1350 BP; and (3) an adaptation to this treeless environment appears in the form of Casuarina arboriculture by 600 BP and a further intensification of agricultural activity occurs after 230 BP. Comparison of palaeoecological records from the eastern highlands with sites further to the west show similar changes over the last 4500 years that have been related to widespread developments in agricultural techniques and to the introduction of new crops in the highlands. The role of climate change during this period is also considered here.