Abstract
The northwestern margins of Motutangi Swamp, located on the Aupouri Peninsula in far-northern Aotearoa, incorporate several former wetland ditch systems below high dunes. Māori ancestors used these ditch systems during the early phase of human occupation in Aotearoa. Radiocarbon dates suggest an occupational period from (if not before) c. 1450 – c. 1700 CE. This thesis will analyse sediment samples from archaeological site N3/638 to investigate these ditch systems. Previous archaeobotanical research at Motutangi has identified starch comparable to kūmara (Ipomoea batatas), taro (Colocasia esculenta) and uwhi/yam (Dioscorea alata) (Horrocks and Barber, 2005, Horrocks et al., 2007b). These studies argue that both crops were productive in the marginally subtropical to warm-temperate climate of the Aupouri Peninsula tombolo. Succeeding publications have disputed the identification of taro remains at N3/638, arguing that the use of light microscopy to analyse microbotanical remains is not sufficient for a confident identification (Crowther, 2009b, Prebble et al., 2020). Calcium oxalate raphides, another type of taro evidence identified at N3/638, have also been critiqued because previous studies did not apply detailed morphometric analysis or utilize scanning electron microscopy (SEM). My thesis will address these critiques by implementing SEM analysis to analyse raphides from N3/638. My research examines starch and raphides extracted from soil deposits at Motutangi. By employing a combination of light microscopy and SEM analysis, this study critiques starch and raphides as diagnostic microbotanical elements at Motutangi. From the samples analysed, I have identified starch granules that are consistent with reference samples of D. alata and I. batatas, and starch amyloplasts and raphides comparable to Araceae, of which C. esculenta was the only Polynesian crop in precontact Aotearoa. SEM examination of archaeological soil samples shows raphides with diagnostic Araceae features including a long thin morphology, asymmetric terminations, and a median groove along two of the raphide’s opposite faces. Collectively and within the context of the variable microbotanical remains at Motutangi, this evidence supports the thesis that early Māori ancestors modified natural wetland environments during the early stages of Polynesian settlement to establish 3 the crop staples of tropical Polynesia, semiaquatic taro and dry soil uwhi, alongside kūmara, in the sub-tropical climate and fields of far-northern Aotearoa.