Thure Cerling, University of Utah
Nuclear weapons testing in the 1950s and 1960s may at last have a silver lining, because researchers can now measure radiocarbon levels to tell when animals (including humans) were born and when they died, critical information in helping to track poachers of elephants, hippos, rhinos and other wildlife.
The technique, outlined in the latest issue of the Proceedings of the National Academy of Sciences, measures radiocarbon-14 deposited in tissue, such as horns, hooves, nails, tusks, hair and teeth. It then uses that information to determine the animal’s birth and death data.
The testing method could help curb the illegal ivory trade, which is wiping African elephants off the planet.
“Ivory seizures and illegal trade of animals is on the scale of many billions of dollars each year,” senior author Thure Cerling, a University of Utah geochemist, told Discovery News. “Where did this material come from? Is it from recently poached animals? Is it from some government stockpile? These are important questions that can serve as a starting point for further investigative work.”
Cerling explained that all animals living today, including humans, have radiocarbon-14 from the bomb testing present in our tissue.
The radiation goes into the environment, into the food chain and then into us. Cerling and his team compare radiocarbon levels in tissues against the fluctuating “bomb curve” of radiocarbon in the atmosphere, pinpointing when the tissues formed and, in some cases, when the animal died.
Radiation from past nuclear bomb testing has been diminishing, so the new testing technique will work until carbon 14 isotopes in the air match background levels about 15 years from now.
Lead author Kevin Uno, a researcher at Columbia University’s Lamont-Doherty Earth Observatory, told Discovery News that the new testing method provides "a valuable tool to help stem poaching and also illegal trade further up the ladder.”
Thure Cerling, University of Utah
“I would also add that there is no price that can be put on the loss of elephants,” Uno said. “It sounds a bit dire, but at the current poaching rates -- 25,000 to 30,000 elephants per year -- some of the smaller forest elephant populations are in real trouble. Elephants are a keystone species in many ecosystems, so their absence in an ecosystem would have many cascading effects.”
The same holds true for rhinos, hippos and many other animals frequently targeted by poachers.
Co-author George Wittemyer said that a three-pronged combative approach is needed: “focusing on in-situ anti-poaching, tackling the demand side in some way that effectively diminishes the ultimate driver of the trend and disrupting the criminalized illegal trade networks.”
The new nuke-based testing technique costs about $500 per sample.
"Each analysis is an investment in discovering the truth about a given case,” said co-author Daniel Fisher of the University of Michigan, with the weight of evidence making it easier for authorities to prosecute people involved in the illegal trade -- the poachers, middlemen and sellers.
Previously, Samuel Wasser, director of the Center for Conservation Biology, formulated another testing method based on DNA evidence. DNA from elephant dung, when matched against DNA from a piece of seized ivory, can tell authorities where the ivory originated.
Wasser and the other researchers pointed out that poachers have become quite clever, by doing things such as changing business names rapidly over the Internet and carving off the tusk’s base, which is optimal for scientific testing.
“There were an estimated 46.5 tons of ivory seized in 2011, with even higher numbers suspected in 2012,” Wasser told Discovery News. “That suggests that close to 50,000 elephants were killed to provide the ivory seized in 2011. With a total population of 400,000 elephants, this is a very serious situation.”