Anthropogenically driven decline and extinction of Sapotaceae on Nuku Hiva (Marquesas Islands,East Polynesia)

Abstract

The native forests of the central and eastern Pacific Islands were extensively modified by Polynesian settlers, but our understanding of these processes is generalised. In the first large study of anthropogenic forest change in the Marquesas Islands, the identification of two members of the Sapotaceae family in prehistoric archaeological charcoal assemblages was notable. Extant species from this family are poorly represented in East Polynesia, and the findings of Planchonella and another taxon (cf. Sideroxylon) indicate their geographical distribution was once more extensive than it is today. They further suggest some Sapotaceae may have been common elements of the indigenous lowland forests of the eastern high islands of Polynesia. Charcoal from the aforementioned taxa were found in early cultural contexts at archaeological sites in three Marquesan valleys, but were almost undetectable in late prehistoric contexts. These declines could be attributed to overexploitation of the wood, forest clearance and seed predation by introduced rats. Data from another archaeological site in the archipelago also suggest that links with reductions in native frugivorous bird populations should be explored. This study has informed on a group of plants that are not well-represented in pollen spectra in the region, and further highlights the usefulness of archaeobotanical data in studying palaeoecological processes in the Holocene.