PHOTO: Mike Koss/Unsplash
PHOTO: Mike Koss/Unsplash

EXPERT REACTION: No genomic evidence for 17th century 'ecocide' on Rapa Nui

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Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts.

New genomic research rejects a contentious theory that ancient inhabitants of Rapa Nui (Easter Island) experienced population declines due to overexploiting the island’s natural resources, known as the 'ecocide' theory. Researchers reconstructed the genomic history of 15 ancient residents, who lived on the island during the past 500 years. They found no evidence of a genetic ‘bottleneck’ that would link to a collapse in the 1600s. Their analysis instead suggests that the island was home to a small population that steadily increased in size until the 1860s, when Peruvian slave raids forcibly removed a third of the island’s population. Their research findings also suggest that Polynesians may have been crossing the Pacific to the Americas well before Europeans arrived in Rapa Nui and well before Columbus arrived in the Americas.

Journal/conference: Nature

Research: Paper

Organisation/s: University of Copenhagen, Denmark; Curtin University, Australia

Funder: Research was financed by a European Research Council (grant agreement no. 679330) and a Swiss National Science Foundation (PP00P3_176977) grant to A.-S.M. J.V.M.-M. is supported by the European Research Council (grant agreement no. 101078151) and VILLUM FONDEN (VIL53099). B.S.d.M. was additionally supported by a Swiss National Science Foundation (PP00P3_176977) grant to O.D. H.S. is supported by the European Research Council (grant agreement no. 101045643). O.D. is a current employee of the Regeneron Genetics Center, which is a subsidiary of Regeneron Pharmaceuticals.

Media release

From: Springer Nature

The decline of the ancient inhabitants of Rapa Nui was unlikely to have been caused by a self-inflicted population collapse, a Nature paper suggests, thereby rejecting a contentious theory of ‘ecological suicide’. The findings shed light on the population history of the island.

Rapa Nui (formerly known as Easter Island) is one of the most remote inhabited places in the world, around 3,700 km west of South America and over 1,900 km east of the closest inhabited island. Two key features of the island’s demographic history have been a point of contention: whether the population of Rapa Nui collapsed after overexploiting local resources in the 17th century (prior to the arrival of Peruvian slave raiders in the 1860s and Europeans in 1722), and whether there was trans-Pacific contact between the Rapanui (the inhabitants of Rapa Nui) and Native Americans.

Working in close collaboration with the current Rapanui community, J. Victor Moreno-Mayar, Anna-Sapfo Malaspinas and colleagues studied the genomes of 15 ancient residents, who lived on the island during the past 500 years. The authors find no evidence of a genetic bottleneck that would correspond to a collapse in the 17th century. Their analysis instead suggests that the island was home to a small population that steadily increased in size until the 1860s, when Peruvian slave raids forcibly removed a third of the island’s population.

In addition, the analyses indicate that — similar to present-day Rapanui individuals — the ancient islanders harboured Native American DNA. They calculate that this mixing is likely to have happened somewhere between 1250 and 1430 CE. Taken alongside archaeological evidence and oral histories, this finding suggests that Polynesians may have been crossing the Pacific well before Europeans arrived in Rapa Nui and well before Columbus arrived in the Americas.

These genomic data will now be used to help to identify and repatriate some of these lost ancestral remains. The paper tells a story not only about resilience in past populations, but also sensitivity in research.

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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Dr Lisa Matisoo-Smith, Professor of Biological Anthropology, University of Otago, comments:

There is something about Easter Island/Rapa Nui that, since the time of first European contact, elicits intrigue, speculation and story-telling. How did the ancient settlers get there and from where? How could people survive in such an isolated and desolate environment? And, of course, there are the Moai. The popular work of Thor Heyerdahl’s “Kon Tiki” and, more recently, Jared Diamond’s “Collapse” has driven much of the fascination with Rapa Nui, their origins and the eventual collapse of their society. However, archaeological, linguistic and biological evidence over the last 50 years has provided answers for most of these questions. Despite this, people seem to be reluctant to let go of the emotive stories.

"We know that the original Polynesian voyagers who discovered and settled Rapa Nui at least 800 years ago were among the greatest navigators and voyagers in the world. Their ancestors had spent at least 3000 years living in an Oceanic environment. They sailed eastwards across thousands of kilometres of open ocean and found almost all habitable islands across the vast Pacific. It would be more surprising if they had not reached the coast of South America. These results do provide some intriguing evidence of the timing of that contact.

"The whole model of ecocide and societal collapse has also been questioned by Pacific scholars, based on a range of archaeological evidence. But now, we finally have ancient DNA evidence that directly addresses these two questions and perhaps will allow us to focus on a more realistic narrative of the history of this intriguing, yet actually rather typical, Polynesian island.

"What is particularly pleasing is that the ancient DNA research was done in consultation with and with the full support of the local community. Not that we should require scientific evidence beyond the collection records, but it is good to know that this will assist with repatriation of these tupuna to Rapa Nui.

Last updated: 11 Sep 2024 2:40pm
Declared conflicts of interest:
No conflicts of interest.

Dr Phillip Wilcox (Ngāti Rakaipaaka, Ngāti Kahungunu ki te Wairoa, Rongomaiwahine, Te Aitanga-a-Mahaki), Associate Professor in Quantitative Genetics, Department of Mathematics and Statistics, Kaikōkiri Māori, Genetics Teaching Programme, and Affiliate of the Bioethics Centre (Te Pokapū Matatika Koiora), University of Otago, comments:

This study demonstrates many strengths but also some limitations inherent in academic research when using modern scientific technologies to address hypothetical events and challenge contemporary views.

"On the positive side it provides strong evidence against long-held views that the native Rapanui peoples (who, like Māori, are of Eastern Polynesian origin) essentially committed ecocide, supposedly leading to population and cultural collapse. By implication this paper raises questions about the academic rigour and motivations of those that have propagated myths of ecocide without strong and compelling evidence. Perpetuation of falsehoods by Westernised academic institutions and other powerful actors has long plagued native peoples around the world, including Aotearoa.

"Dispelling such false narratives is challenging, but as shown by these researchers, the tools of modern science can play a role in providing more informed analysis. Moreover, these authors appeared to have taken a strong ethical approach to study design and conduct: they consulted with local Rapanui community to ensure the study was conducted in an appropriate manner and that the narratives written by the researchers were acceptable to indigenous Rapanui community representatives.

"They also ensured there were benefits from the study in regard to repatriating the remains of ancestors - which is important in many Eastern Polynesian as well as other cultures. As such, the research team is to be commended for their efforts to ensure the research does not perpetuate further harms to the community being studied – as has happened multiple times in the past in genetics-based investigations.

"One limitation of this study however, is that information generation appears to be based entirely on technologies of modern science, without substantive inclusion of traditional knowledge from indigenous Eastern Polynesians. There is no mention of any efforts to obtain oral histories of supposed population collapse from the Rapanui people themselves, despite widespread practices of handing down purukau (stories) over generations in Eastern Polynesian cultures.

"Moreover, I’m aware that within some oral histories are names of native American ancestors along with purukau about them and where they lived, which indicate it was Eastern Polynesian navigators that went to South and Central America, rather than vice versa. This is consistent with other opinions – for example Matisoo and Gosling (2020) and Crowe (2018) who provided strong rationale for contact between native Americans and Eastern Polynesian occurring in Central and/or South America.

"This study – along with previously published genetic sciences-based research showing evidence of native American ancestry in Polynesians - could have been strengthened by inclusion of indigenous knowledge and a more comprehensive understanding of the histories of Eastern Polynesian peoples. By ignoring such traditional knowledge, researchers and other actors such as scientific journals, unfortunately perpetuate the assumption that indigenous knowledge is of little or no value in addressing key questions about very populations they are actually studying."

References:

  1. Matisoo-Smith, L. and A. Gosling. 2020. Did ancient Americans settle in Polynesia? The evidence doesn’t stack up. Accessed 10 September 2024.
  2. Crowe, A. 2018. Pathway of the Birds. Auckland. Bateman. 2018. 288 pp. ISBN 978-1-86953-961-0
Last updated: 11 Sep 2024 2:45pm
Declared conflicts of interest:
No conflicts of interest.

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