Holocene volcanic activity, vegetation succession, and ancient human land use: Unraveling the interactions on Garua Island, Papua New Guinea

An integrated approach to the reconstruction of vegetation history and human land use during the Holocene on Garua Island, Papua New Guinea analysed sediments and plant microfossils (phytoliths and starch granules) together with archaeological data. The long-term record is punctuated by a series of volcanic disasters, where repeated cycles of massive destruction were followed by differing cycles of forest regeneration. The plant microfossil record shows that instead of long-term forest recovery, the overall pattern of regeneration was progressively more disrupted. Through time regeneration was halted earlier in the sequence and then reverted to increasingly open plant communities dominated by grasses. The temporal patterns of burning, stone artefact discard, and plant introductions demonstrate that the increased impact of human systems of land management was primarily responsible for the temporal patterning. Most notably, the study shows that human interference begins much earlier than expected given previous archaeological research and relatively intensive burning and landscape modification, possibly indicating cultivation, predates the introduction of Lapita pottery.