National Geographic : 2012 Jul
• book, that ancient Easter Islanders committed unintentional ecocide. ey had the bad luck, Diamond argues, to have settled an extremely fragile island---dry, cool, and remote, which means it's poorly fertilized by windblown dust or volcanic ash. (Its own volcanoes are quiescent.) When the islanders cleared the forests for re- wood and farming, the forests didn't grow back. As wood became scarce and the islanders could no longer build seagoing canoes for shing, they ate the birds. Soil erosion decreased their crop yields. Before Europeans showed up, the Rapanui had descended into civil war and cannibalism. e collapse of their isolated civilization, Dia- mond writes, is "the clearest example of a society that destroyed itself by overexploiting its own resources" and "a worst-case scenario for what may lie ahead of us in our own future." The moai, he thinks, accelerated the self- destruction. Diamond interprets them as power displays by rival chie ains who, trapped on a remote little island, lacked other ways of strut- ting their stuff. They competed by building ever bigger statues. Diamond thinks they laid the moai on wooden sledges, hauled over log rails---a technique successfully tested by UCLA archaeologist Jo Anne Van Tilburg, director of the Easter Island Statue Project---but that re- quired both a lot of wood and a lot of people. To feed the people, even more land had to be cleared. When the wood was gone and civil war began, the islanders began toppling the moai. By the 19th century none were standing. Easter Island's landscape acquired the aura of tragedy that, in the eyes of Diamond and many others, it retains today. the scattered shards of fact, though, and you get a more op- timistic vision of the Rapa Nui past---that of archaeologists Terry Hunt of the University of Hawaii and Carl Lipo of California State Univer- sity Long Beach, who have studied the island for the past decade. It's a vision peopled by peaceful, ingenious moai builders and careful stewards of the land. Hunt and Lipo agree that Easter Island lost its lush forests and that it was an "ecologi- cal catastrophe"---but the islanders themselves weren't to blame. And the moai certainly weren't. ere is indeed much to learn from Easter Island, Hunt says, "but the story is di erent." His and Lipo's controversial new version, based on their research and others', begins with their own excavation at Anakena beach. It has convinced them that the Polynesians didn't arrive until . . 1200, about four centuries later than is commonly understood, which would leave them only five centuries to denude the land- scape. Slashing and burning wouldn't have been enough, Hunt and Lipo think. Anyway, another tree killer was present. When archaeologists dig up nuts from the extinct Easter Island palm, the nuts are o en marred by tiny grooves, made by the sharp teeth of Polynesian rats. e rats arrived in the same canoes as the rst settlers. Abundant bones in the Anakena dig suggest the islanders dined on them, but other- wise the rodents had no predators. In just a few years, Hunt and Lipo calculate, they would have overrun the island. Feasting on palm nuts, they would have prevented the reseeding of the slow- growing trees and thereby doomed Rapa Nui's forest, even if humans hadn't been slashing and burning. No doubt the rats ate birds' eggs too. Of course, the settlers bear responsibility for bringing the rats; Hunt and Lipo suspect they did so intentionally. ( ey also brought chickens.) But like invasive species today, the Polynesian rats did more harm to the ecosystem than to the humans who transported them. Hunt and Lipo see no evidence that Rapanui civilization collapsed when the palm forest did; based on their own archaeological survey of the island, they think its population grew rapidly after settlement to around 3,000 and then remained more or less stable until the arrival of Europeans. Cleared fields were more valuable to the e loss of Easter Island's forests was an "ecological catastrophe"---but the islanders were not to blame, the new theory says. And the moai certainly weren't.