AbstractsBiology & Animal Science

The Chatham Islands were a challenging environment for East Polynesian colonisers. The successful long term settlement of these islands can be attributed to the first people applying and adapting Polynesian strategies to the colonisation of an unfamiliar environment. Previous studies have suggested that settlement and subsistence practices were entirely focused upon the collection of wild plants and fauna, throughout the Moriori sequence with a heavy dietary reliance on one marine species, the New Zealand fur seal (Arctocephalus forsteri). This interpretation is not consistent with the results of this research. In this thesis a holistic multi-proxy research design is used to identify terrestrial plant use by Moriori and the landscape modification which is associated with the introduction of East Polynesian subsistence practices. The primary data sets employed are the ethnographic and historical accounts of Moriori subsistence, archaeological investigations of the broad-leaved forests and associated sites, anthracological and palynological analyses to identify past vegetation regimes and the anthropogenic effects, and to date when humans began to modify the environment. The results suggest that after an initial period of rapid population growth, even though marine mammals were still available in large numbers, the first settlers began to modify the environment to increase terrestrial production. It is argued that the environmental changes occurred in part to increase the productivity of wild plants, particularly bracken fern (Pteridium esculentum). The most important change to the vegetation was the intentional introduction and management of the mainland New Zealand endemic tree Corynocarpus laevigatus. The broad-leaved forests, a previously under-researched component of Moriori subsistence, are shown to have been actively managed by Moriori. They were an integral component of the subsistence practices in the ‘late’, post-1650AD, Moriori sequence. The introduction and cultivation of Corynocarpus laevigatus was essential to the long term colonisation of the Chatham Islands in the absence of the standard tropical East Polynesian cultigens.