Purakaunui pit’s kumara dated to 1450

Researchers have found evidence of ancient kumara near Dunedin, overturning the orthodox view that the climate was too cold for the tuber’s use south of Banks Peninsula.

A new study published in the science journal Plos One reported that early Polynesians once stored kumara — South American sweet potato — in rectangular pits dug into sand dunes at Purakaunui, eastern Otago, less than 30km north of central Dunedin.

"This rewrites the archaeology and history textbooks as to how far south Maori used and stored kumara in Aotearoa," University of Otago archaeologist Associate Prof Ian Barber said yesterday.

Ancient kumara remnants had been accurately carbon-dated to the mid-15th Century, about when moa went extinct, suggesting that the open pit method used to store kumara near Dunedin was an attempt to "mitigate" the lost moa food supply, he said.

The rectangular pits represented the southernmost evidence of kumara storage in Oceania, more than 200km south of Polynesia’s previously recognised southern kumara margins in Canterbury.

"It demonstrates that certainly in the 15th century that people were using it here."

"From an academic point of view this is a pretty remarkable discovery.

"Having evidence of Polynesia’s southernmost ancient kumara turn up close to Dunedin is pretty cool, I think."

The find was consistent with old Maori oral traditions of kumara having been used in the South, and highlighted the need for researchers to take Maori oral traditions more seriously.

It was unclear whether these stored kumara (rua kumara) were imported from warmer northern localities or harvested locally in microclimate production, he said.

The research was approved and encouraged by manawhenua Kati Huirapa Runaka ki Puketeraki and Nicola Taylor, for Purakaunui Block Inc. Maori landowners.

Prof Barber had led the research, backed by university grants and a Marsden award, and by radiocarbon specialist and co-author Prof Tom Higham, of Oxford University.

Kati Huirapa Runaka ki Puketeraki manager Suzanne Ellison said the research was"very affirming about traditions and matauraka [traditional knowledge] relating to Huriawa Peninsula".

john.gibb@odt.co.nz