The mystery of Easter Island and its Polynesian inhabitants, long debated, may be a rather modest answer – the Rapa Nui native inhabitants of the Pacific island may have simply exhausted their food sources and either died off or fled the island. An international team of researchers, examining soil samples taken from the island best known for its nearly 900 moai monumental statues, concluded that nutrients in the soil eventually were depleted, pushing the Rapa Nui into decline long before European explorers arrived in 1722.
Fox News on Jan. 28 reported that the researchers “examined agricultural soil chemistry and land use trends to get a better picture of any shrinking and swelling in population numbers. To gauge population trends, the researchers reviewed six agriculture sites on the 63-square-mile island. At each one, they measured how much water had penetrated the surface of obsidian spear points, which told them how long the obsidian had been exposed and thus how old the spear points were.”
Researchers examined obsidian, a naturally occurring volcanic glass categorized as igneous rock, to determine moisture and nutrient levels at various locations on the 15-mile long island. The multiple digs performed by the team showed the inhabitants may have migrated to different areas of the island in order to farm, and eventually, as the soil closest to the interior side of the volcanic island lost its ability to produce annual crops, the inhabitants died out and left, leaving only a small populace behind.
According to a release published by science news site Eurekalert.com, geographers and archaeologists from the University of California, Santa Barbara, teamed up to determine what caused the decline of the Rapa Nui society. Their findings are published in the Proceedings of the National Academy of Sciences.
“In the current Easter Island debate, one side says the Rapa Nui decimated their environment and killed themselves off,” said UCSB’s Oliver Chadwick, a professor of Geography. “The other side says it had nothing to do with cultural behavior, that it was the Europeans who brought disease that killed the Rapa Nui. Our results show that there is some of both going on, but the important point is that we show evidence of some communities being abandoned prior to European contact.”
While it has been suggested that political revolution in combination with disease epidemics may have been at the root of the decline in civilization from 15,000 to approximately 2,000, it would seem that it was more the decline of arable land that decimated the inhabitants. “When we evaluate the length of time that the land was used based on the age distribution of each site’s obsidian flakes, which we used as an index of human habitation, we find that the very dry area and the very wet area were abandoned before European contact,” Chadwick said.
Still, a small nucleus of Rapa Nui, able to react to regional variants and overcome natural environmental barriers, remained robust. Researchers said they likely began producing sufficient crops, or more self-sustaining annual harvests that did not downgrade the nutrient content of the soil.
“The pullback from the marginal areas suggests that the Rapa Nui couldn’t continue to maintain the food resources necessary to keep the statue builders in business,” Chadwick concluded. “So we see the story as one of pushing against constraints and having to pull back rather than one of violent collapse.”
The big-headed monoliths of Easter Island remain one of the islands most enduring mysteries and attractions. According to History.com, the average moai bust is 13 feet high with a weight of 13 tons. The statues are “carved out of tuff (the light, porous rock formed by consolidated volcanic ash) and placed atop ceremonial stone platforms called ahus. It is still unknown precisely why these statues were constructed in such numbers and on such a scale, or how they were moved around the island.”
The Easter Island mystery: Solved?