Nearly 900 moai stand silent watch on Easter Island (Rapa Nui), yet because of a lack of a written or oral history from the native islanders, we have no clear idea why they exist. Even worse, we don’t know happened to the people who erected them. Now, a team of researchers from Spain think they’ve narrowed down what led to their civilization’s collapse.
Over the years, many researchers have tried to pinpoint the exact reason why the once-thriving Rapa Nui civilization declined so drastically by the time the island came to European attention on Easter Sunday in 1722.
The most popular theory falls into the category of human greed: The Rapa Nui people, after arriving from east Polynesia between 800 and 1200 CE, depleted the island of its resources. Termed as ecocide, this led to their forests being wiped out—a theory supported by a shift from palm pollen to grass pollen in island sediments. A cultural collapse soon followed.
Many potential theories for the island’s decline
However, there are other compelling ideas. One in particular posits that the Polynesians arrived a little later—1200 to 1300 CE—and brought rats with them. The rats then consumed an enormous amount of palm fruit across the island, leading to deforestation. Cultural collapse would happen later, thanks to the European arrival—a well-documented genocide, that was also coupled with new diseases brought to the island and enslavement of many Rapa Nui people.
“These different interpretations may be complementary, rather than incompatible,” said Dr. Valentí Rull, senior researcher of the Spanish National Research Council in Barcelona, in a Phys.org statement. “In the last decade, there’s been a burst in new studies, including additional research sites and novel techniques, which demand that we reconsider the climatic, ecological and cultural developments that occurred.”
With technological advances, some of the holes missing from the previous evidence are beginning to be filled in. For example, pollen samples have been the primary source for most of the conclusions about the island—but there are other, more reliable, ways to determine what exactly happened.
And so, the authors reviewed a large number of more recent Rapa Nui studies. According to their paper in Frontiers in Ecology and Evolution, they performed various analyses in an attempt to piece together all these various documents into a coherent story.
Using a (finally) complete set of sedimentary samples for the past 3,000 years on Easter Island, they were able to analyze the environmental shifts on the island—showing the weather patterns, droughts, and wet seasons that likely drastically affected the forests’ growth, as well as sea travel to the island in the first place.
Radiocarbon dating and DNA analysis also have illuminated where humans lived on the island, what plants they grew and ate, and what cultures played a role before the arrival of the Europeans. For example, the presence of sweet potato paired with the genes of the human remains indicates that Amerindian settlers likely joined the Polynesian settlers on the island at some point before European arrival.
But most importantly, their review contradicts the leading theory of what happened to the native peoples on Easter Island, pointing more towards genocide instead of ecocide.
“These findings challenge classical collapse theories and the new picture shows a long and gradual process due to both ecological and cultural changes,” said Rull. “In particular, the evidence suggests that there was not an island-wide abrupt ecological and cultural collapse before the European arrival in 1722.”
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Image credit: Ben Leshchinsky/Fickr
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