A new method for dating
elephant tusks, described in the latest
issue of the Proceedings of the National
Academy of Sciences (PNAS), could make it
easier for law enforcement agencies to enforce
the ban on Illegal Ivory trade.
Elephant poaching is
now at its highest level since record-keeping
began in 2002, according to a 2012 report
by the Convention on International Trade
in Endangered Species(CITES).
New York, 01 June 2013
- Nearly 25 years after an international
ban was placed on ivory, African elephants
are being slaughtered at a rate that could
bring about their extinction this century.
By allowing the trade of ivory acquired
before 1989 to continue, the ban put the
burden on law enforcement to distinguish
between legal ivory and poached. Now, a
new method for dating elephant tusks, described
in the latest issue of the Proceedings of
the National Academy of Sciences (PNAS),
could make it easier to enforce the ivory
ban and save the African elephant from extermination
say researchers. The method might also be
applied to endangered rhinoceroses and other
wildlife.
"We've developed a tool that allows
us to determine the age of a tusk or piece
of ivory, and this tells us whether it was
acquired legally," said the study's
lead author, Kevin Uno, a postdoctoral researcher
at Columbia University's Lamont-Doherty
Earth Observatory. "Our dating method
is affordable for government and law enforcement
agencies and can help tackle the poaching
and illegal trade crises."
FURTHER RESOURCES
Elephants in the Dust- The African Elephant
Crisis
Elephant tusks grow ring by ring, recording
what plants the animals ate. Elephant tusks,
it turns out, also record how much radioactive
carbon was in the air, giving scientists
a time marker for all those meals. During
photosynthesis plants absorb radiocarbon
put into the air by nuclear weapons testing
in the 1950s and 1960s. The radiocarbon
travels up the food chain, finding its way
into the fingernails, hair, teeth and tusks
of animals. By comparing radiocarbon levels
in those tissues against the fluctuating
"bomb curve" of radiocarbon in
the atmosphere, forensic scientists can
pinpoint when the tissues formed, and in
some cases, when the animal died. The method
works for tissue formed from about 1955
until the bomb curve, or concentration of
carbon 14 isotopes in the air, reaches background
levels, 10 to 15 years from now.
In the highly-regulated market for legal
ivory, finding tusks for scientific research
is not easy. With the help of a Salt Lake
City zoo and several agencies in Kenya,
the researchers gained access to the tusks
of two elephants: Misha, euthanized at Utah's
Hogle Zoo in 2008, and Amina, who died naturally
at Kenya's Samburu National Preserve in
2006. Study co-author Thure Cerling, a geochemist
at the University of Utah, read about Misha's
death in the local newspaper and immediately
called the zoo. "They told us, we can
work with you because we haven't buried
her yet," he said. The researchers
traveled to Kenya for Amina's tusk, which
they sawed into domino-sized samples under
the watch of Kenya Wildlife Service.
In the lab, the researchers
measured radiocarbon levels at the base
of each tusk to independently calculate
when the elephants died. Similar tests were
done on monkey hair, hippo canines, oryx
horn and elephant tail hairs to verify that
the method worked across tissues of different
ages. Two steps were key to getting precise
ages. The researchers sampled each tusk
lengthwise, along the growth ring, and used
the most advanced technology-an accelerator
mass spectrometer-to measure the radiocarbon.
In addition, the study calculated growth
rates for the teeth, which can be applied
to elephant teeth in the fossil record to
understand how climate and vegetation varied
in Africa when humans were evolving. In
other applications in wildlife forensics,
the technique can be applied to rhino horns,
which are intensely sought after for their
perceived medicinal benefits.
The researchers' method
complements a forensics tool developed at
the University of Washington's Center for
Conservation Biology that allows researchers
to track ivory seizures back to their source.
In a 2004 study in PNAS, center director
Sam Wasser laid out a map of African elephant
populations based on DNA from their dung
that, when matched against a piece of seized
ivory, could tell investigators where the
ivory originated. The DNA tool has helped
law enforcement identify where elephants
are being poached; the new radiocarbon tool
tells them when. "It can reliably tell
us, is it legal ivory or not?" said
Wasser, who was not involved in the study.
Elephant poaching is
now at its highest level since record-keeping
began in 2002, according to a 2012 report
by the Convention on International Trade
in Endangered Species (CITES).More elephants
are slaughtered today?at the rate of 30,000
a year-than before the 1989 ban, experts
say. Some 423,000 African elephants are
left, according to the International Union
for Conservation of Nature's elephant database.
Much of the illegal
ivory leaves Africa through Tanzania and
Kenya and ends up in Asia, where it is carved
into religious icons, decorative art and
signature seals popular among the Chinese
and Japanese. While China imports about
70 percent of the smuggled ivory, the next
biggest market is the United States, where
ivory is worked into the handles of guns
and knives, said Richard Ruggiero, an expert
at the U.S. Fish and Wildlife Service. Global
seizures of illegal ivory reached a new
record in 2011, at 86,000 pounds (39,000
kilograms), equaling nearly 6,000 elephants.
But the magnitude of the problem is no match
for law enforcement. "With poaching
rising exponentially because of exploding
demand we are actually losing ground,"
said Ruggiero.
A kilogram of ivory-about
2.2 pounds-fetched $200 in 2004; by 2007,
a kilo was worth $850. Escalating prices
are driving Africa's notorious militias,
including the Lord's Resistance Army in
northern Uganda and south Sudan, the Shabab
in Somalia and the Janjaweed of Darfur to
kill elephants for tusks to buy guns, The
New York Times reported last year. Organized
crime is now involved in smuggling ivory
out of Africa, leading former U.S. Secretary
of State Hillary Clinton to speak outagainst
the problem last year. At a Senate Committee
of Foreign Relations hearing last year,
former U.S. Sen. John Kerry (now Clinton's
successor) testified to the global security
threat posed by elephant poaching.
The disappearance of
the African elephant will mean more than
the loss of a majestic, highly intelligent
creature, ecologists say. It could change
the structure of Africa's savannahs and
rain forests. "They are environmental
architects," said Wasser. "They
keep woods down in the savannah and are
the most important dispersers of seeds of
rain forest trees. The central African rain
forest is the second most important area
on earth for capturing carbon dioxide and
storing it."
Other authors are: Jay
Quade, University of Arizona; Daniel Fisher,
University of Michigan; George Wittemyer,
Colorado State University; Iain Douglas-Hamilton,
Save the Elephants; Samuel Andanje, Patrick
Omondi and Moses Litoroh, Kenya Wildlife
Service.
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