Was Easter Island (Rapa Nui) The Victim Of Ecocide? Maybe Not

Don't Blame the Natives: It was a rat that caused the sudden collapse of Easter Island's civilization CHARLES C. MANN, WSJ, 7-30-11. Excerpts:

"Rapa Nui once was much more rich and populous. Roggeveen had remarked on the island's lack of trees and speculated that it formerly had been heavily forested. As the island's population rose, the popular theory goes, its people cut down all the trees for slash-and-burn farming and as rollers to transport statues. With the forest gone, Rapa Nui's soil degraded; unable to feed themselves, Mr. Diamond argued in his best-selling "Collapse" (2005), Easter Islanders faced "starvation, a population crash, and a descent into cannibalism." The fall was abrupt and overwhelming; scores of giant statues were abandoned, half-finished. Roggeveen had discovered a ruin—and a powerful eco-parable. Books and articles by the hundred have pointed to Rapa Nui as the inevitable result of uncontrolled population growth, squandered resources and human fecklessness. "The person who felled the last tree could see it was the last tree," wrote Paul G. Bahn and John Flenley in "Easter Island, Earth Island" (1992). "But he (or she) still felled it." "The parallels between Easter Island and the whole modern world are chillingly obvious," Mr. Diamond proclaimed. "The clearest example of a society that destroyed itself by overexploiting its own resources," he said, Rapa Nui epitomizes "ecocide," presenting a stark image of "what may lie ahead of us in our own future." No, it doesn't, write archaeologists Terry Hunt and Carl Lipo in "The Statues That Walked," a fascinating entry in the pop-science genre of Everything You Know Is Wrong. Messrs. Hunt and Lipo had no intention of challenging Mr. Diamond when they began research on Rapa Nui. But in their fourth year of field work, they obtained radiocarbon dates from Anakena Beach, thought to be the island's oldest settlement. The dates strongly indicated that the first settlers appeared around A.D. 1200—eight centuries later than Heyerdahl and other researchers had thought. Wait a minute, the authors in effect said. Rapa Nui is so remote that researchers believe it must have been settled by a small group of adventurers—a few dozen people, brave or crazy, in boats. The new evidence suggested that their arrival had precipitated catastrophic deforestation "on the scale of decades, not centuries." The island then probably had only a few hundred inhabitants. Some ecologists estimate that the island originally had 16 million palm trees. How could so few people have cut down so much so fast? Puzzle piled upon puzzle. Why was there no evidence of "large-scale prehistoric farming"? Other Polynesian societies covered their land with miles of terraces. Easter Islanders, by contrast, "seemed to be underutilizing the island"—a contrast that "was all the more perplexing given the enormous amount of effort they had apparently put into making their massive statues and stone [plinths]." Rapa Nui's forest had been mainly composed of giant palms, which have soft, fibrous wood. Used as rollers, they would have been crushed by the load. No farming, no statue-schlepping—why would the islanders have removed the forest? The real culprit, according to "The Statues That Walked," was the Polynesian rat (Rattus exulans), which stowed away on the boats of the first Polynesian settlers. In laboratory settings, Polynesian rat populations can double in 47 days. Throw a breeding pair into an island with no predators and abundant food and arithmetic suggests the result: ratpocalypse. If the animals multiplied as they did in Hawaii, the authors calculate, Rapa Nui would quickly have housed between two and three million. Among the favorite food sources of R. exulans are tree seeds and tree sprouts. Humans surely cleared some of the forest, but the real damage would have come from the rats that prevented new growth. "Their success was short-lived. As Messrs. Hunt and Lipo point out, the 18th and 19th centuries were terrible times to reside in a small, almost defenseless Pacific nation. Rapa Nui was repeatedly ravaged by Peruvian slaving parties and nonnative diseases. In a 2007 article in Science, Mr. Diamond estimated that hundreds of laborers were needed to move the statues, suggesting that the eastern settlements of the island alone had to have "a population of thousands"—which in turn was proof of the island's destructive overpopulation. By showing that the statues could have been moved by much fewer people, Messrs. Hunt and Lipo have removed one of the main supports of the ecocide theory and the parable about humankind it tells."