Many theories evolved when the civilization that once inhabited Easter Island vanished, but recent evidence shows that the truth is not as simple as any one of these alone.
Dr. Valenti Rull said that these different interpretations may be complementary, rather than incompatible, adding that 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.
Rull is the lead author of an overview on the holistic reassessment of Easter Island history.
Until recently, the evidence has been limited. Prior sedimentary samples commonly used as historical records of environmental change were incomplete, with gaps and inconsistencies in the timeline.
Using the latest analytical methods, Rull and his collaborators are beginning to shed light on many of these questions. Complete sedimentary samples now show a continuous record of the last 3000 years, showing how droughts and wet seasons may have influenced the island's population. Sea travel depended on such weather patterns, resulting in periods of cultural exchange or isolation.
Rainfall also impacted native palm forests, with droughts potentially contributing to the island's eventual deforestation. Radiocarbon dating and DNA analysis of artifacts and human remains are also showing where the inhabitants lived on the island, what they farmed and ate, and the influence of cultures beyond their Polynesian ancestors.
Rull said that 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.
The article is published in the open-access journal Frontiers in Ecology and Evolution.
