Botanical remains of the last 1800 years from Tarawa, Republic of Kiribati, reveal ancient aroid (Cyrtosperma merkusii and Colocasia esculenta) pit cultivation and other cultigens

Abstract

Recent advances in the study of the antiquity and development of ancient Pacific Island agriculture have been made at sites across much of the region by the application of a range of microfossil techniques, namely analysis of pollen, phytoliths, and starch. Unlike in Melanesia and Polynesia, the application of these techniques in Micronesia is limited. Here we report on microfossil analysis of Micronesian archaeological pit deposits from Tarawa atoll, in the Gilbert Islands (western Kiribati), covering the last 1,800 years. Results show local pit cultivation of Cyrtosperma merkusii and Colocasia esculenta. Together with microfossils of other subsistence taxa, namely Cocos nucifera, Morinda citrifolia, and Pandanus tectorius, and 14C dated macrofossil charcoal of Artocarpus altilis, the evidence is consistent with the atoll subsistence tradition of Remote Oceania. Because plants have differential production and preservation of pollen, phytoliths, and starch, the study shows the value of using combined analyses of these microparts.