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Easter Island’s Collapse May Have Surprising Explanation

The downfall of Easter Island may have had more to do with pre-existing environmental conditions than degradation by humans, according to a new study of the remote speck of land made famous by its enormous stone statues.

Easter Island, also known as Rapa Nui, was first settled around the year 1200, and Europeans landed on its shores in 1722. The circumstances surrounding the collapse of the indigenous population of Rapa Nui are hotly debated both in academia and popular culture. UCLA researcher Jared Diamond argued in his 2005 book "Collapse" that prior to European contact, the indigenous people of the island degraded the environment to the extent that they could no longer thrive.

The new study suggests that Easter Island's people were indeed suffering before Europeans came along. The story of their downfall, however, may be less about human-caused environmental degradation and more about the natural environmental constraints on the 63-square-mile (163 square kilometers) isle. [Image Gallery: The Walking Statues of Easter Island]

"The results of our research were really quite surprising to me," said study co-author Thegn Ladefoged, an anthropologist at the University of Auckland in New Zealand. "Indeed, in the past, we've published articles about how there was little evidence for pre-European-contact societal collapse."

The changes on Easter Island have been well-documented, archaeologically: Over time, elite dwellings were destroyed, inland agricultural fields were abandoned, and people took refuge in caves and began manufacturing more and more spear points made out of volcanic glass called obsidian, perhaps suggesting a period of war and upheaval.

The problem with pinning down the island's history is that the dates of all these events and abandonments remain murky. To clarify the timeline, the researchers analyzed more than 400 obsidian tools and chipped-off obsidian flakes from six sites scattered around the island, focusing in particular on three with good information on climate and soil chemistry.

One site showed a rapid decline in obsidian use after 1650. Another showed a decline by 1710, and the third showed steady use until 1850 or later. Differences in rainfall levels and soil quality at those sites appear to explain the uneven decline, the researchers said.

What this means is that the people of Easter Island may have been struggling against natural environmental barriers to success, rather than degrading the environment themselves, the researchers reported this week in the Proceedings of the National Academy of Sciences.

— Stephanie Pappas, LiveScience

This is a condensed version of a report from LiveScience. Read the full report. Follow Stephanie Pappas on Twitter and Google+. Follow LiveScience on Twitter, Facebook and Google+.