The iconic moai statues of Easter Island serve as a reminder that a vibrant civilization once lived there many years ago, but how and why the islanders vanished remains unknown.
There are several theories surrounding the civilization's mysterious disappearance. For one, the people could have suffered from dwindling resources. Other experts suggest that European settlers and subsequent illness, slave trade or stow-away rats could have wiped out the islanders.
In fact, shards of glass found scattered across Easter Island were once thought to be evidence of massive warfare brought on by competition for food. Alas, a recent analysis confirmed that these artifacts were nothing more than your average farming tools.
Therefore, a new study from the Spanish National Research Council in Barcelona, Spain, suggests that the civilization's disappearance cannot simply be explained by any one of these theories alone.
"These different interpretations may be complementary, rather than incompatible," said Valentí Rull, lead author of the study. "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."
Previously, studies on Easter Island's history were largely based on sedimentary or pollen samples, which serve as good indicators of environmental change. However, these samples alone could not provide a clear picture of what really happened to the people of Rapa Nui, the traditional name of Easter Island.
With inconsistencies among data and gaps in the timeline, many fundamental questions have remained unanswered - until now.
The latest analytical methods have shed new light not only on the disappearance of the ancient civilization, but also on how it emerged in the first place.
For instance, complete sedimentary samples now show a continuous record of the last 3000 years, revealing how periods of drought or rainfall could have impacted agricultural practices or native palm forests, with droughts potentially causing the island's eventual deforestation, or worse - food shortages.
Researchers also note that such weather patterns would have also affected sea travel, leading to periods of either cultural exchange or geographic isolation.
Furthermore, radiocarbon dating and DNA analysis of artifacts and human remains have also given scientists a better idea of where exactly the islanders lived, what they farmed and ate, and the influence of outside cultures.
"These findings challenge classical collapse theories and the new picture shows a long and gradual process due to both ecological and cultural changes. In particular, the evidence suggests that there was not an island-wide abrupt ecological and cultural collapse before the European arrival in 1722," Rull explained.
While pieces of the Easter Island puzzle are still missing, it is now clear that neither environmental nor human activities are solely responsible for the civilization's downfall. All factors - climate, ecology and culture - need to be considered in future studies.
The findings were published in March 29 issue of the journal Frontiers in Ecology and Evolution.
