Plant microfossil analysis of soils from Polynesian stonefields in South Auckland, New Zealand

Pollen, biogenic silica and starch residue analyses of soils from archaeological stonework complexes in South Auckland, northern New Zealand, reveal evidence of palaeo-environments and vegetation, including agricultural crops. A broad sampling strategy involving minimal disturbance to features was used (35 composite soil samples from six sites) to determine the extent to which the complexes were used for agriculture, identifying specific crops and pinpointing areas for subsequent intensive excavation. Starch and other residues of Ipomoea batatas (sweet potato) and Colocasia esculenta (taro), introduced by prehistoric Polynesians, were identified in a range of stonefield features at four sites. Zea mays (maize), an early European introduction, was identified at two sites. The study also highlights problems of downward displacement and preservation of plant microfossils in dryland soils. The data represent initial extensive, multi-microfossil analysis of archaeological stonework complexes.