How do Terry Hunt and Carl Lipo of the University of Hawaii
explain the mystery of Easter Island being treeless?
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Answer from Gillgarey
Terry Hunt and Carl Lipo of the University of Hawaii...
http://askville.amazon.com/Terry-Hunt-Carl-Lipo-University-Hawaii-explain-mystery-EasterIsland-treeless/AnswerViewer.do?requestId=62870890
Anthropologist Terry Hunt is digging up intriguing evidence about causes of deforestation on
Easter Island and raising questions about the role of rats in the Pacific
Throughout their voyages across the Pacific, ancient Polynesians were accompanied by rats.
Anthropologists believe these rodents either stowed away on sailing vessels or, more likely,
were brought along as a source of protein for the human colonists. Until recently, however,
the ecological and societal impact of these well-traveled rodents had come under scant
consideration. In March 2006, Terry Hunt, a professor of anthropology and an archaeology
specialist at UH MÄnoa, published a paper in the journal Science asserting that colonization
of Rapa Nui likely occurred around 1200 AD.
...
In September 2006, Hunt published a more detailed examination of the state of the current
evidence on Rapa Nui deforestation in The American Scientist, including further discussion
of the role of rats and how the activity of the rodents fits with current evidence. Hunt also
has an article going to press in the Journal of Archaeological Science addressing the rat
issue.
According to Hunt, upon arrival in Rapa Nui the rats feasted on the seeds of endemic trees,
in particular on the seeds of Jubaea palms that were the primary forest cover of the island.
...
Hunt believes that researchers to date may have greatly underestimated the environmental
impact of rats in island ecosystems across the Pacific. "Rats could be introduced to other
islands without really devastating [them], but as you get into the remote parts of the
Pacific, the impacts would likely have been much greater," says Hunt.
...
Below that, Hunt found no signs of human presence. He did find molds in the clay created
by the roots of the native Jubaea palms, implying that the palms existed in greater numbers
immediately before man's arrival. When Hunt received word from the radiocarbondating
laboratory that his samples from the bottom layers dated back only to 1200 AD, he began
to consider whether colonization had actually occurred centuries later than Rapa Nui
scholars had previously supposed. Earlier radiocarbon samples had implied similar dates but
none were as technically sound as those Hunt retrieved and analyzed.
This did not change the date of deforestation; other researchers had determined fairly
conclusively that the number of trees on the island went into a steep decline soon after
1200 AD. The new radiocarbon evidence, combined with clear evidence of rat consumption
of Jubaea seeds, caused Hunt to ponder whether the rodents' impact could have been a
more important factor in the disappearance of Rapa Nui's forests than generally believed,
and whether the peak Rapanui population had perhaps never risen above roughly 3,000.
...
Rats might be able to do many of the things that we've said humans had done, and maybe
we've overlooked this," says Hunt. With Donald Drake, a UH professor of botany, Hunt has
arranged a conference in the spring of 2007 that will bring together experts in island
ecology, geography, and anthropology to more closely examine the impacts rodents may
have on islands.
...
And, according to Hunt, the early Rapanui used rock mulching techniques (packing fields of
crops with rocks) to reduce soil erosion and protect plantings, implying that soil erosion due
to high winds was always a problem on the island. Ultimately, Hunt believes, it will become
clear that there never was a self-induced population crash on Rapa Nui and that, in part due
to the prolific rats, the island was never able to support more than about 3,000 inhabitants.
...
Diamond, for his part, declared in a newspaper interview that Hunt was wrong and that rats
had arrived on every other Polynesian island and nowhere else did the forest go into rapid
decline.
...
Sources: http://www.zoominfo.com/people/Hunt_Terry_46169527.aspx
Gillgarey 73 months ago
Answer from sekar
Terry Hunt and Carl Lipo of the University of Hawaii...
Easter Island's mystery brooding statues atop a treeless Polynesian island fascinates
tourists and scholars alike.
And inspires debate.
"Who or what destroyed the ancient palm woodland on Rapa Nui (Easter Island)?" ask
German ecologists Andreas Mieth and Hans-Rudolf Bork, in an upcoming paper in the
Journal of Archaeological Science. "The circumstances, causes and triggers of these
environmental changes are the subject of persistent scientific discussion."
And how. In 2005, Pulitzer-prize winner Jared Diamond revived public awareness of the
island with Collapse: How Societies Choose to Fail or Succeed. "What were they thinking
when they cut down the last palm tree?" he asked in the book. The question had puzzled
many scholars looking at the depopulated, deforested island, finally concluding the
inhabitants had denuded it of food-providing palms to build sledges for statues and roofs for
homes, an ecological parable of self-destruction.
But only a year later, another explanation surfaced in a series of papers by Terry Hunt and
Carl Lipo of the University of Hawaii. First, they set the date for colonization of the island to
1200 A.D. in a radiocarbon dating paper in the journal Science, more recent by at least a
century than past estimates. Next, they proposed, based on DNA evidence and chewed
palm remains in the Journal of Archaeological Science, that Polynesian rats brought with
those immigrants had been the culprits behind deforestation, eating palm tree nuts.
Without predators to keep rat numbers in check, the rodents ate most of the seeds and the
older trees had mainly died out without reproducing by 1772 when Europeans arrived in
ships. Those Europeans wiped out the islanders, they suggested, through disease and later
enslavement. "It was genocide, not ecocide, that caused the demise of the Rapanui. An
ecological catastrophe did occur on Rapa Nui, but it was the result of a number of factors,
not just human short-sightedness," Hunt wrote in The American Scientist magazine.
In their new study, however, Mieth and Bork, both of Germany's Christian Albrechts
University of Kiel, "disagree with the hypothesis of a major rat impact" to explain Easter
Island's demise. In their study, they look at the charcoal remains from fires, evidence of the
spread of slash and burn agriculture from the island's shore to its peak. "Over large areas, a
single layer of charcoal and ashes several millimeters in thickness can be found deep below
the recent surface and on top of the prehistoric garden soils that belong to the period of
woodland gardening," they write. "The extensive distribution of charcoal layers can only
have one explanation: widespread fires in the woodland of Rapa Nui."
Looking at the march of tree burning over time, cut palm stumps and a lack of rat bite
marks on palm nuts found in the charcoal layers, they conclude "deforestation was an act of
humans."
"But we were never talking about rats killing mature trees," Hunt says in an interview. "It's
very tempting to see one explanation for everything, all people or all rats, but what we were
saying was that rats surely played a role on Easter Island." He rejects the notion that a lack
of rat-eaten palm nuts in charcoal layers proves anything, saying, "rats are unlikely to eat
charcoal."
Besides, he says, "how can you explain the idea of rats not having an effect?" Unhindered
by predators and provided ample food, the rat population must have exploded on Easter
Island, he argues, eating nuts even as colonists raised farms.
About the only thing the competing viewpoints can agree upon is that drought, a third
suspected cause, didn't have a big effect on Easter Island's palm forests, which in 1100 A.D.
covered about 70% of the island. "The question is how much of a role did each player have
and how did they interact?"
Of course, Hunt acknowledges, the early colonists likely brought rats with them. "But it's
unlikely they could have seen ahead to the results of either farming or bringing rats," he
says. "Blaming humans for everything is too simple."
Sources: http://m.usatoday.com/News/983464/full/;jsessionid=B4B8E6E8A4B0D3CCFD9D
AAFBDD713764.wap1
sekar 73 months ago