Decline of ecology dogged with doubt

University of Otago researchers Dr Karen Greig and Dr Nic Rawlence with the remains of a kuri ...
University of Otago researchers Dr Karen Greig and Dr Nic Rawlence with the remains of a kuri (Polynesian dog), brought by humans from the Pacific Islands, which they say may have contributed to changes in New Zealand’s ecology. PHOTO: GREGOR RICHARDSON
When it comes to pin-pointing the sources of New Zealand’s ecological decline since the arrival of humans, scientists may have been barking up the wrong tree.

The arrival of humans and the kiore (Pacific rat) they brought with them, has been well documented by scientists as bringing about major changes to New Zealand’s environment.

But University of Otago Southern Pacific Archaeological Research Unit co-director Dr Karen Greig and Zoology Department Otago Palaeogenetics Laboratory director Dr Nic Rawlence believed kuri (Polynesian dogs) had been overlooked, and even erroneously exonerated by some scientists, for their ecological impact.

The duo have taken a fresh look at kuri and argue dogs should be included in any extinction models pertaining to the impact of humans.

Dr Greig said their impact on biodiversity had been difficult to scientifically assess, but advances in biomolecular methods might enable scientists to take a closer look.

New Zealand’s unique animals evolved over millions of years, in the absence of mammalian predators.

Dr Rawlence said the arrival of humans marked the beginning of major changes to the country’s biodiversity, including widespread extinctions, range contractions, population bottlenecks and biological turnover events.

"To date, research has focused on the direct impacts of humans, such as over-hunting, and environmental modification, like the widespread burning of forests, and predation by kiore.

"Kuri have largely been overlooked in contributing to the ecological consequences of human colonisation with some scientists saying they are ‘exonerated’ from any culpability regarding the impacts of human colonisation."

The duo believed rather than being confined to villages, kuri could have had a widespread impact on New Zealand’s birds, reptiles and marine mammals as a predator of medium-sized animals, including moa chicks and juveniles, takahe, kakapo, kiwi, burrowing seabirds, seals and sea lions.

"Kuri may have even formed feral populations in pre-European New Zealand but will require further research we are currently undertaking," Dr Rawlence said.

Dr Greig believed kuri potentially amplified already significant impacts of Polynesian colonists.

"As such, kuri should be included in models of human impact in addition to over-hunting, environmental modification and predation by kiore," she said.

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