The Collapse Of Easter Island Society


Scientists led by Prof Thegn Ladefoged of the University of Auckland have proposed a study that challenges the leading hypothesis on the demise of the Easter Island society. According to the research, significant changes occurred in land use and population dynamics long before the European discovered the island. These extreme changes were not caused by natural disaster but were the result of the environmental constraints of the small sized island.

Moai facing inland at Ahu Tongariki, restored by Chilean archaeologist Claudio Cristino in the 1990s. Image credit Wikipedia
Moai facing inland at Ahu Tongariki, restored by Chilean archaeologist Claudio Cristino in the 1990s. Image credit Wikipedia

“The results of our research were really quite surprising to me,” said Prof Ladefoged, who is the senior author of the paper published online in the Proceedings of the National Academy of Sciences.

During the research, Prof Ladefoged and his team analysed over four hundred obsidian artefacts that have provided important details about the island and the way of life.

One of the main goals of the research was to better understand the islands timeline, focusing on three main sites from which they had good information about the composition of the soil, and climatic conditions, recovering large samples of artifacts.

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock, produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows.

Obsidian absorbs water after being exposed to air, that way researchers were able to measure the amount of water in the obsidian determining when they were made.

Prof Ladefoged and his team estimated land use and population increases and declines basing their theory on the number of tools made during each period, providing relatively accurate information.

One of the sites where research was done, located on the northwest coast (prone to drought due to its location in the rain shadow of the Terevaka volcano) showed an increase in population between 1220 and 1650 followed by a rapid decline.

The second site that was researched was less prone to drought, showing an increase in use from 1200 to 1480 with steady use up until 1705 when it finally declined. According to research on the third and final site, the researchers noticed an increase in the use of the land starting about 1250 maintaining a fairly constant use until 1850.

The first Europeans that arrived at Easter Island did so in 1722. This has provided scientists with enough information to believe that something was going wrong on Easter Island before the first Europeans arrived. The study of Prof Ladefoged suggests that the inhabitants of Easter Island struggled with the natural limitations of the Islands ecology and not environmental degradation.

“It is clear that people were reacting to regional environmental variation on the island before they were devastated by the introduction of European diseases and other historic processes,” Prof Ladefoged said.


Source:

Proceedings of the National Academy of Sciences of the United States of America

 


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