Microfossils of introduced starch cultigens from an early wetland ditch in New Zealand

Pollen, phytolith and starch residue analyses of a wetland ditch at Motutangi, far northern New Zealand reveals evidence of early environment and introduced cultigens. During the period of use or infilling, local vegetation largely comprised Gleichenia-Restionaceae swamp and disturbed forest. Starch residues of Colocasia esculenta (taro), Dioscorea sp. (yam) and Ipomoea sp. (possibly I. batatas, sweet potato) are identified, here, and suggest that the ditch systems of far northern New Zealand may have been used for extensive cultivation of taro and other crops. The results include the first direct evidence of Dioscorea in ancient Polynesia.