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Exposing the Myth of "Environmental Self-Destruction": The True Story of Easter Island

Recent studies disprove the long-held belief of ecological collapse on Easter Island, and show that the population has remained stable through effective resource management over a long period of time.

The "Moai" statues on Easter Island. Illustration: depositphotos.com
The "Moai" statues on Easter Island. Illustration: depositphotos.com

The traditional story that the settlers of Easter Island caused their own collapse through environmental depletion has been re-examined by new research that shows there was a stable population that was managed using brilliant agricultural practices like rock gardening. Despite the geographical challenges and limited resources, the islanders supported their population with a combination of sweet potato cultivation and the use of marine resources, as evidenced by satellite images and archaeological finds.

The inhabitants of Easter Island have found brilliant ways to adapt to the harsh environment

Recent research disproves the long-held belief of ecological collapse on Easter Island, and shows that the population has remained stable through effective resource management.

About 1,000 years ago, a small group of Polynesians sailed thousands of kilometers across the Pacific Ocean to settle in one of the most isolated places in the world - a small, uninhabited island they called Rapha Noi. There they erected hundreds of "moai", or huge stone statues that now stand as symbols of a vanished culture. Over time, their numbers swelled to unsustainable levels; They cut down all the trees, killed the sea birds, exhausted the soils and eventually destroyed their environment. Their population and culture collapsed, and only a few thousand people remained when the Europeans discovered the island in 1722 and named it Easter Island. At least that's how the story has been told for a long time, as stated in academic studies and popular books such as Jared Diamond's 2005 "Breakdown".

A reexamination of the self-destruction theory of the environment in the framework of a new study

New research challenges this narrative of environmental self-destruction, saying that the Rapha Nui population never reached unsustainable levels. Instead, the settlers found ways to cope with the island's harsh limitations, maintaining a small and stable population for centuries. The evidence: a sophisticated new inventory of shiny "stone gardens" where the islanders grew highly nutritious sweet potatoes, a staple of their diet. The gardens covered only enough space to support a few thousand people, the researchers say. The study has just been published in the journal Science Advances.

 "This shows that the population could not have been as large as some of the previous estimates," said lead author Dylan Davis, a postdoctoral researcher in archeology at Columbia University's School of Climate Sustainability. "The lesson learned in the research is the opposite of the collapse theory. People were able to be very resilient in the face of limited resources by changing the environment in a way that supported the population.”

Gardening with stones

Stone gardens were the key to feeding the population of Rapha Noi, now commonly known as Easter Island. Robert DiNapoli, co-author of a new study on the genes, examines one of them. Credit: Carl Lippo

Geographical and agricultural challenges in Easter Island

Easter Island is perhaps the most remote inhabited place on Earth, and one of the last to be inhabited by humans, if not the last. The nearest continent is central Chile, nearly 2,200 miles to the east. About 3,200 miles to the west are the tropical Cook Islands, from which settlers are believed to have sailed around 1200 AD.

The island, which is about 165 square kilometers in size, is made entirely of volcanic rock, but unlike rich tropical islands such as Hawaii and Tahiti, the eruptions stopped hundreds of thousands of years ago and the nutrients that the lava brought have long been eroded from the soils. Located in the subtropical zone, the island is also drier than its tropical brethren. To make things more challenging, the ocean shores surrounding the island are very steep meaning the islanders had to work harder to catch sea creatures than those living on Polynesian islands surrounded by lagoons and accessible and fertile reef cities.

To cope, the settlers used a technique called stone gardening, or rock cover. This includes scattering stones over low-lying areas that are at least partially protected from salt spray and wind. Among the stones, they planted yams. Studies have shown that stones from golf ball size to large boulders disrupt the drying winds and create turbulent air circulation, which reduces the highest temperatures during the day and raises the lowest at night. Smaller pieces, broken by hand, reveal fresh surfaces loaded with minerals that are released into the soil over time. Some islanders still use these gardens, but even with all this work, their yield is marginal. The technique was also used by indigenous peoples in New Zealand, the Canary Islands and the southwestern United States, among others.

A reassessment of historical population estimates

Some scientists have argued that the island's population must once have been much larger than the first 3,000 inhabitants observed by Europeans, in part because of the massive moai; It seems that it would have required a lot of people to build them, according to their logic. So in recent years, researchers have tried to evaluate these populations, among other things, by investigating the extent of the genes and estimating their production capacity. The first Europeans estimated that they covered 10% of the island. A 2013 study based on visible light and near-infrared satellite imagery estimated 2.5% to 12.5% ​​– a wide margin of error because this spectrum only distinguishes between rock and vegetation areas, not all of which are gardens. Another study from 2017 identified about 7,700 dunams, or 19% of the island, as suitable for growing sweet potatoes. Making various assumptions about crop yields and other factors, studies have estimated that past population sizes may have been as high as 17,500, or even 25,000, although they could also have been much lower.

In the new study, members of the research team conducted surveys of the gardens' soil and characteristics over five years. Using this data, they trained a series of machine learning models to identify genes through satellite images targeting a new near-infrared spectrum, which highlights not only rocks but also places of high soil moisture and nitrogen, which are key features of the genes.

Rafa Noi's moai on Easter Island were established by the Polynesian settlers of Easter Island. Moai are large stone sculptures depicting the chiefs of the tribes and important figures of the island. These sculptures are not only significant cultural relics but also engineering marvels, reflecting the advanced skills in sculpture and transportation of the ancient Rapha Noi.

Research conclusions

The researchers concluded that the stone gardens occupy only about 188 dunams - less than half a percent of the island. They say they may have missed some small areas of growth, but not enough to make a big difference. Based on several assumptions, they say that if the entire diet was based on sweet potatoes, these gardens could have supported about 2,000 people.

for the scientific article

Respectable entry on Easter Island in Wikipedia

More of the topic in Hayadan:

One response

  1. And what about all the evidence about the wars that were there? And what happened to the thousands of trees that were on the island and were cut down? Also, an interesting commissioned study by whom

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