The traditional view holds that the residents of Easter Island exhausted the island’s resources, leading to a significant population decline. A new research report questions this belief, suggesting that there actually existed a sustainable small society on the island.
For a long time, scholars have generally believed that hundreds of years ago, the island of Rapa Nui (Easter Island) in the Pacific Ocean experienced a severe population decline. It was widely thought that the local residents overexploited the land, resulting in deforestation, depletion of soil resources, and the near extinction of seabirds. As a result, the population on the island may have plummeted from a peak of 25,000 people to just a few thousand.
However, a new study published on June 21 in the journal Science Advances pointed out that Easter Island, known for its giant moai statues, actually had much less arable land at that time than previously believed. Based on this finding, scientists suggest that the population on the island did not actually experience a drastic decrease but rather started with a relatively low number of inhabitants.
These research findings add a new perspective to existing academic studies, outlining a social image different from the commonly told narrative: this was a society that could adapt to the limitations of the land, rather than one that faced ecological destruction due to human activities.
“In the past at least a decade, the view that population growth and improper use of natural resources led to ecological disaster has been increasingly questioned in the case of Easter Island,” said Sue Hamilton, an Easter Island research expert at University College London, in an interview with The Guardian, not involved in the study.
“Overall, this research highlights that while the people of Easter Island are often described as a declining culture restricted by social-political competition, overexploitation of the ecological environment, and overexploitation of giant stones, if we can reframe it as a Polynesian island culture that has prospered for nearly a millennium, such discussion would be more beneficial,” said Dale F. Simpson, an anthropologist and archaeologist at the University of Illinois, who was not part of the study, in an interview with New Scientist.
A statement from Columbia University noted that Polynesians settled on Easter Island about a thousand years ago. This isolated island in the southeastern Pacific Ocean is about 2,200 miles west of Chile.
Composed of volcanic rock, the island has poor soil, making farming challenging with limited soil productivity and a lack of freshwater resources. To overcome these challenges, the inhabitants of the island utilized rock gardening techniques, spreading crushed stones on the soil to grow crops like sweet potatoes. This method could regulate airflow to keep the land cool during the day and warm at night, while helping to retain soil moisture. Weathered rocks also added mineral nutrients to the soil.
When Europeans arrived in the 18th century, there were only about 3,000 people living on Easter Island. Early studies found that about 2.5% to 19% of the land may have been covered by rock gardens. Based on the area of these farmed lands and the assumption that only a large society could construct so many giant moai statues, previous estimates suggested the island could have supported a population of 17,500 to 25,000. This speculation further led to the view that the population on the island may have suffered significant decline due to excessive farming before the arrival of the Europeans.
However, the authors of the new study pointed out that previous research overestimated the area of rock gardening by mistaking roads, lava flows, and vegetation as arable land. In this new paper, the authors used satellite imagery and machine learning techniques to assess the actual land area used for rock gardening.
They found that on this approximately 63-square-mile island, less than one-third of a square mile was used for rock gardening – a number that is only one-fifth of the previous most conservative estimate. In their research report, the authors noted that even with locals relying on fish and other crops for sustenance, Easter Island could not have supported a large population.
“Our study confirms that the island could only sustain a few thousand people at most,” said Dylan Davis, an archaeologist at Columbia University and co-author of the study, in an interview with The Guardian. “Therefore, contrary to the narrative of ecological disaster believed in the past, the population seen by Europeans upon their arrival may represent the peak period of Easter Island society, when the population number matched the sustainable development level of the island.”
However, other researchers argue that the new study overlooks some rock gardening sites. Christopher Stevenson, an archaeologist at Virginia Commonwealth University, told Science News in an interview that the study severely underestimated the distribution range of rock gardening on Easter Island and the potential number of inhabitants. Stevenson, who was not involved in the new research, had conducted early studies on rock gardening on Easter Island.
Hamilton also stated in an interview with The Guardian that accurately estimating the population based solely on the area of rock gardening poses challenges. “This issue is actually much more complex than what a single study can explain,” she told the media.