Maine wood turtle (Glyptemys insculpta). Credit: Center for Wildlife Studies
Wildlife trafficking threatens biodiversity as poachers remove animals from wild populations into the illegal pet trade. Many traffickers attempt to evade prosecution by falsely claiming that trafficked animals were bred in captivity, a tactic known as animal “laundering”; the true origin of a confiscated animal can be difficult to prove, posing problems for authorities attempting to combat the trafficking problem. A research team including scientists from the Center for Wildlife Studies, Maine Department of Inland Fisheries and Wildlife, University of Arkansas and University of Maine have now developed a novel technique for identifying trafficked Maine wood turtles, which examines the stable isotopes in claw clippings and uses a statistical model to distinguish between legally and illegally obtained animals.
Wood turtles are a commonly poached and trafficked species in Maine, which has led to declining wild populations across the state. The new forensic method focuses on the carbon and nitrogen stable isotopes in the turtles’ bodies, which can vary depending on the animals’ diets. As wild and captive-bred wood turtles have vastly different diets, the stable isotope signatures in their tissues was expected to differ. The researchers collected claw clippings from the turtles and analyzed their isotopic signatures using isotope ratio mass spectrometry (IRMS). The IRMS data was processed using the team’s newly-developed statistical model, which was designed to differentiate between captive and wild turtles based on the carbon and nitrogen stable isotopes of the claw samples.
The team compared the isotopes of 35 wood turtles from the wild to those of 36 captive-bred wood turtles and found that the model was highly accurate in predicting whether a turtle was wild or captive. Overall, the method had a 97% success rate, accurately identifying all but two of the 71 turtles as captive or wild. According to the authors, their study was the first to use stable isotope analysis to distinguish between freshwater turtles of wild or captive origin. The new method could potentially aid Maine authorities in combating wildlife trafficking, prosecuting traffickers and protecting the state’s native turtle species. This study was published in the journal Biology.
“This technique will provide conservation law enforcement officials a much-needed wildlife forensic tool and is the first crucial step in developing a more widespread application used to help combat the illegal turtle trade,” said first author John Hopkins, president and associate professor of the Center for Wildlife Studies in Maine. “The need is particularly important because despite reptiles’ overwhelming prevalence in the wildlife trade, a relative paucity of funding is allocated to their protection.”
The researchers hope to improve their technique to ultimately achieve 100% accuracy and further expand its applications to other geographic regions and vulnerable turtle species.