More than 90 percent of ivory in large, seized shipments came from elephants that died less than three years before, according to a new study.
A team of scientists at the University of Utah, the University of Washington and partner institutions came to this conclusion by combining a new approach to radiocarbon dating for ivory samples with genetic analysis tools developed by UW biology professor Sam Wasser.
Their approach gave conservationists a picture of when and where poachers are killing elephants. The paper, which includes Wasser as a co-author, was published Nov. 7 in Proceedings of the National Academy of Sciences.
“This work provides for the first time actionable intelligence on how long it’s taking illegal ivory to reach the marketplace,” said Lesley Chesson, a co-author and CEO of Isoforensics. “The answer is not long at all, which suggests there are very well-developed and large networks for moving ivory across Africa and out of the continent.”
Wasser led efforts to gather ivory samples from large stockpiles seized by law enforcement officials between 2002 and 2014. Alerted by contacts in law enforcement, officials in the seizing country or from internet monitoring, Wasser collected some samples himself and directed colleagues in sampling the rest. Officials in countries that had seized these samples were helpful and cooperative, he added.
“They really appreciate the collaborative effort,” Wasser said.
These samples consisted of small sections, only one or two inches on a side, from the inside surface of the base of the tusk — the freshest material with the radiocarbon signature most recent to the death of the elephant. Wasser said the sight of so many tusks in one place was distressing, particularly the tusks of young elephants shot by poachers to attract other larger elephants.
“Sometimes, many of the tusks are so small that you can’t understand why the animal was even killed,” Wasser said. “Tusks can weigh less than one pound, with almost no carvable ivory on them.”
Combining Cerling’s radiocarbon data with Wasser’s genetic analysis to determine the geographic origin of the ivory, the researchers constructed a picture of which regions have established rapid pipelines to get poached ivory to market. In the study, seized ivory is classified as either originating in East Africa, the Tridom region of west-central Africa, West Africa or Zambia. Additionally, samples were classified as having a rapid lag time of less than 12 months, intermediate lag time of 12 to 24 months or a slow lag time of greater than 24 months.
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