IN ONE of the most isolated places on Earth, a mysterious people flourished for hundreds of years before their penchant for deforestation triggered an environmental catastrophe and the collapse of their society. So runs the conventional story of Easter Island – which now looks as if it may be completely wrong.
Terry Hunt of the University of Hawaii and Carl Lipo at California State University in Long Beach radiocarbon-dated traces of charcoal from the earliest human traces found in a new excavation on Easter Island. Their findings suggest that humans colonised the island in AD 1200, some 400 years later than previously thought (Science, DOI: 10.11.26/science.1121879). The new date fits with recent revisions of human colonisation of other Pacific islands (Â鶹´«Ă˝, 24 April 2004, p 38), and if correct means that the people who colonised Easter Island and erected a stunning series of giant stone statues began to chop down and burn some of its 16 million palms soon after they arrived.
There is, however, little evidence that this is what precipitated the islanders’ demise, Hunt says. He is working on a detailed study of the ecological collapse on Easter Island. The ecological record shows that islanders replaced the forests with a viable agricultural system, and is providing clear evidence that they grew sweet potatoes, yams, taro, bananas and sugar cane.
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“The loss of trees on Easter Island does not appear to be associated with any agricultural catastrophe”
Hunt suggests that Polynesian rats accompanying the colonisers helped devastate the natural vegetation on Easter Island just as they did on Hawaii and New Zealand. “They basically stop the regeneration of trees by destroying the seeds,” he says.
The loss of the trees does not, however, appear to be associated with any agricultural catastrophe, and there is no clear archaeological evidence of a population collapse before Europeans arrived in 1722, Hunt says. An alternative explanation for the society’s collapse could be that introduced European diseases and the slave trade were to blame.
Supporters of the idea that deforestation eroded soils and degraded the environment have extrapolated evidence from limited sites to the whole island, says Thegn Ladefoged of the University of Auckland, New Zealand, who has investigated agriculture on Easter Island. Working with a team led by Chris Stevenson of the state of Virginia’s Department of Historic Resources, Ladefoged has analysed the quality of the soil and documented the use of agricultural “rock gardens” in the island’s interior.
In a study published last year in the journal Antiquity, Hunt, Lipo and Britton Shepardson of the University of Hawaii thoroughly documented the island’s networks of prehistoric paths for the first time. This survey, the researchers believe, shows the islanders used these paths to move their statues from a quarry at Rano Raraku, and suggests the roads were built at different times by different groups of people. Generally, the findings support the idea that the construction and movement of statues might have been conducted by smaller groups than once thought necessary, Hunt says.
