Reconstruction of vegetation changes on Atiu Island, southern Cook Islands, East Polynesia, based on pollen analysis: Verification of human impacts

Fujiki Toshiyuki, Sakai Keisuke, Okuno Mitsuru

The results of a pollen analysis conducted on Atiu Island, Cook Islands, revealed dramatic vegetation changes at ca. 1,600 cal BP (ca. 350 cal CE). These changes included a decrease in Pandanus pollen and Cyatheaceae spore, increase in herb pollen grains and herbal fern spores, increase in charcoal fragments, and increase in pollen grains of plants probably transported by Polynesians. The results suggest that the grasslands and fernlands expanded due to disturbances caused by large-scale deforestation. However, there are no archaeological data indicating human settlement on Atiu Island during this period. Cultivated plant pollen grains, such as those of sweet potato, and charcoal fragments increased rapidly after ca. 1100 cal CE. This may indicate human arrival on Atiu Island occurred in two stages. This is consistent with previous paleoenvironmental studies, like those from Lake Tiroto. Dynamic reconstruction of human settlement based on paleoenvironmental changes derived using sediments requires analysis of multiple sites from various catchments.

The Quaternary Research(Daiyonki-kenkyu)

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https://doi.org/10.4116/jaqua.62.2202