Ecosystem Collapse and Agrarian Innovation in the Highlands of New Guinea
by
Simon G. Haberle
Department of Archaeology & Natural History, Research School of Pacific & Asian Studies, Australian National University, Canberra, ACT 0200, Australia.

In the highlands of New Guinea, the development of agriculture as an indigenous innovation during the early Holocene is considered to have resulted in rapid loss of forest cover, a decrease in biodiversity and increased land degradation over thousands of years. But how important is human activity in driving the function and composition of vegetation communities over millennial timescales, particularly in light of recent evidence for abrupt fluctuations in climate during the Holocene? A re-evaluation of the rate and direction of vegetation changes that occurred since the late glacial transition in five palaeoecological sites from highland valleys (1400-1890 m altitude) where intensive agriculture is practiced today is presented. 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 forest clearance and exploitation have been identified at around 7800 cal BP. Subsequent vegetation changes are characterised by peaks in the rate of vegetation change centred around 6500, 4500 and 1500-1000 cal BP that led towards more open landscapes and a shift towards higher species turnover within forest communities (slow growing shade-tolerant species become rare). These episodes of change are best explained by the complex interaction between the adoption of innovative land management practices and external influences such as volcanic activity and climate variability. The implications of these findings for ecosystem conservation and sustainability of agriculture in New Guinea are discussed.

Date received: August 6, 2002

Copyright © 2002 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caji-51.