Page 25 - Environment: The Science Behind the Stories

THE SCIENCE BEHIND THE STORY

What are the
Lessons of
Easter Island?

A mere speck of land in the vast Pacific
Ocean, fully 3750 km (2325 mi) from
South America, Easter Island is one of
the most remote spots on the globe.
Yet this far-flung island—called Rapa
Nui by its inhabitants—is the focus of an
intense debate among scientists seek-
ing to clarify its enigmatic history and
decipher the lessons it has to offer us.
Ever since European explorers
stumbled upon Rapa Nui on Easter
Sunday, 1722, outsiders have been Easter Island’s immense statues
struck by the island’s barren landscape.
Early European accounts suggested on stone tablets discerned characters Today, only one native bird species is
that the 2000–3000 people living on etched in the form of palm trees. left. Remains from charcoal fires show
the island seemed impoverished, By studying pollen and the remains that early islanders feasted on fish,
subsisting on a few meager crops and of wood from charcoal, archaeologist sharks, porpoises, turtles, octopus,
possessing only stone tools. Yet the Catherine Orliac found that at least 21 and shellfish—but in later years they
forlorn island also featured hundreds of other plant species—now gone—had consumed little seafood.
gigantic statues of carved rock. How also been common. Clearly the island As resources declined, researchers
could people without wheels or ropes, had supported a diverse forest. Forest concluded, people fell into clan war-
on an island without trees, have moved plants would have provided fuelwood, fare, revealed by unearthed weapons
90-ton statues 10 m (33 ft) high as building material for houses and and skulls with head wounds. Rapa
far as 10 km (6.2 mi) from the quarry canoes, fruit to eat, fiber for clothing— Nui appeared to be a tragic case of
where they were chiseled to the sites and, researchers guessed, logs and ecological suicide: A once-flourishing
where they were erected? Apparently fibrous rope to help move statues. civilization depleted its resources and
some calamity must have befallen a Pollen analysis showed that destroyed itself. In this interpretation—
once-mighty civilization. trees declined, replaced by ferns advanced by Flenley and writer
Many researchers have set out and grasses. Then between 1400 Paul Bahn, and by scientist Jared
to solve Easter Island’s mysteries. A and 1600, pollen levels plummeted. Diamond in his best-selling 2005 book
key discovery was that the island was Charcoal in the soil proved the forest Collapse—Rapa Nui seemed to offer a
once lushly forested. Scientist John had been burned, likely in slash-and- clear lesson: We on our global island,
Flenley and his colleagues drilled cores burn farming. Researchers concluded planet Earth, had better learn to use
deep into lake sediments and exam- that the islanders, desperate for forest our limited resources sustainably.
ined ancient pollen grains preserved resources and cropland, had defor- When Terry Hunt and Carl Lipo
there, seeking to reconstruct, layer by ested their own island. began research on Rapa Nui in 2001,
layer, the history of vegetation in the With the forest gone, soil eroded they expected simply to help fill gaps
region. Finding a great deal of palm away (data from lake bottoms showed in a well-understood history. But sci-
pollen, they inferred that when Poly- a great deal of sediment accumulating). ence is a process of discovery, and
nesian people colonized the island Erosion would have lowered yields of sometimes evidence leads researchers
(a.d. 300–900, they estimated), it was bananas, sugarcane, and sweet pota- far from where they anticipated. For
covered with palm trees similar to the toes, perhaps leading to starvation and Hunt, an anthropologist at University of
Chilean wine palm—a tall, slow-grow- population decline. Hawaii at Manoa, and Lipo, an archae-
ing tree that can live for centuries. Further evidence indicated that ologist at California State University,
Archaeologists found ancient wild animals disappeared. Archaeolo- Long Beach, their work ended up
palm nut casings buried in soil near gist David Steadman analyzed 6500 convincing them that nearly everything
carbon-lined channels made by palm bones and found that at least 31 bird about the traditional “ecocide” interpre-
roots. Researchers deciphering script species provided food for the islanders. tation was wrong.

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