KINGSTON — A University of Rhode Island doctoral student who surveyed the state for freshwater turtles and studied their habitat preferences found that the once-common spotted turtle is in trouble, due largely to habitat disturbance.
Scott Buchanan, a New Jersey native working in collaboration with URI Associate Professor Nancy Karraker, repeatedly visited 88 different wetlands in the state over three years and captured nearly 2,000 turtles of four different species. Just 50 were spotted turtles, a species considered by the state to be of high conservation concern and a candidate for the U.S. endangered species list.
“Throughout they’re range, populations of spotted turtles have declined extensively, and we can certainly say with a good deal of confidence that’s also the case in Rhode Island,” said Buchanan, who graduated from URI last month. “I found that they are associated with wetlands in forested landscapes, which means they are susceptible to development, forest fragmentation, wetland alteration and other human disturbances.”
Buchanan said that the largest populations of spotted turtles he found were in locations where human disturbance has been minimal. “So now it’s a matter of managing those landscapes in an appropriate way,” he added.
Habitat alteration is not the only conservation concern the species faces, however. The illegal collection of wild turtles for the pet trade is also a problem.
“Spotted turtles will command a formidable sum in the pet trade, which is unfortunate,” Buchanan said, noting that he encountered people during his research who had captured spotted turtles they intended to bring home to keep as pets but released them at his insistence. “It’s really easy for someone to deplete an entire population of them very quickly.”
During his turtle surveys, Buchanan also found a non-native turtle called a red-eared slider in more wetlands than he found spotted turtles. The slider is a species commonly purchased at pet stores and frequently released into the wild after their owners no longer wish to care for them. He said that wetlands close to human populations, especially those with easy access from roads, are the most likely place to find red-eared sliders in Rhode Island.
“They’re an especially detrimental invasive species,” he said. “It’s a good bet that all the sliders we found are turtles that were bought at pet stores. We don’t know if they’re reproducing in the wild.”
Eastern painted turtles and common snapping turtles, the two most common species of freshwater turtles in Rhode Island, were found in abundance during Buchanan’s turtle surveys.
“They were everywhere, with no strong pattern as to where we might find them across different landscape types,” he said.
What can be done to protect the region’s declining spotted turtle populations?
“It would mean protecting and preserving wetlands, especially forested wetlands, including small wetlands like vernal pools where they sometimes overwinter,” Buchanan said. “It would also mean minimizing fragmentation of the landscape surrounding those wetlands. And it’s also really important that we protect the turtles themselves from illegal collection. That’s an increasing concern among conservation biologists.”
As Buchanan prepares to graduate from URI, he will share his data with a region-wide team of biologists collecting information about the three turtle species being considered for inclusion on the U.S. endangered species list – spotted, wood and Blanding’s turtle.
“The habitat information we collected could help determine where populations of spotted turtles occur and help protect and appropriately manage those populations into the future,” he said.