Natural and human impacts in a 35 000-year vegetation history in central New Britain, Papua New Guinea

Abstract

Phytoliths and micro-charcoal from the Yombon Airstrip archaeological site in central New Britain, Papua New Guinea, provide the longest vegetation history record yet available for the New Guinea islands. The record begins about 35 kya with the first evidence for human presence at the site and, with the exception of the Last Glacial Maximum period, is continuous to the present. Three other sites provide supplementary evidence, including plant macro-remains, from the early Holocene onwards. The record is punctuated by a series of volcanic events, which are reflected in the vegetation record by alternating frequencies of closed forest and regrowth elements. Micro-charcoal is present from the oldest levels and fluctuates in frequency throughout the sequence, increasing substantially from the terminal Pleistocene-early Holocene onwards. This coincides with the first appearance of panicoid grasses and a range of potential cultivars including bananas and Saccharum. Increased levels of burning coinciding with the appearance of potential plant cultivars may indicate shifts in plant food production leading to cultivation from the early Holocene onwards. This compares favourably with previously reported evidence from Garua Island off the north coast of New Britain. The combination of trends in burning, vegetation clearance and appearance of potential cultivars on New Britain appears to parallel changes in the Papua New Guinea highlands at a similar time, and suggests regional similarities in subsistence and vegetation management practices from before the LGM onwards. Further studies are needed to clarify the timing and extent of these shifts across the region, and to provide a vegetation picture for the period before human colonisation of New Britain.