URSI Project Tracks Blandings Turtles in Nearby Habitat
She’s probably pushing 60 years old, but a turtle named Lady, who is being tracked this summer by Vassar biology professor Marshall Pregnall and his students, is apparently living a full and active life. “Lady has done at least a couple of kilometers in just the past week (looking for appropriate places to lay her eggs) — she’s a real traveler,” Pregnall says.
Lady is a Blandings turtle, one of more than two dozen of the threatened species being tracked and studied this summer in a swamp about eight miles from the campus under the auspices of Vassar’s Undergraduate Research Summer Institute (URSI). The 30-acre swamp, which lies between some high school athletic fields and a golf course, is one of the few known habitats for the Blandings turtles in New York and one of the few east of the upper Midwest, their principal habitat.
Every day, Pregnall and and his students, Clara Cardillo ’15, Morgan Foster ’14, and Nnennia Mazagwu ’17 visit the swamp, don chest-waders, and track the turtles’ movements (about 20 of them have radio transmitters attached to their shells), monitor their nesting areas and check for evidence of predators such as skunks, possums and raccoons that commonly feast on turtle eggs. They return every evening – often remaining until well after midnight -- to track the turtles and observe them and keep predators away if they are preparing their nests or laying their eggs.
Foster, a math major, became interested in the turtle conservation project when she took Pregnall’s aquatic ecology class last year. She says she and Cardillo spend much of their time trying to figure out ways to discourage the other animals from destroying the turtles’ eggs, a process called “aversive conditioning.” When they find a nest, Foster and Cardillo place a cage over it to protect it. They also place quail eggs in open areas, then douse the eggs with hot pepper or spicy oil, hoping that when the predators eat them, they’ll get an unpleasant surprise and will be less likely to eat eggs they find in the future.
“Our objective is to conserve as many eggs as possible – to discourage the predators from digging them up,” Foster says.
Cardillo, an environmental studies major, says she joined the URSI Blandings turtle project because she hopes to become a research biologist and wants some hands-on experience in tracking and monitoring endangered animals. Learning the turtles’ habits enables her and Foster to help them survive. “We’ve compiled data on where the nests are located, where the babies are able to survive, and where they’re more likely to be invaded,” she says.
Keeping the tiny colony of Blandings turtles safe has been an uphill battle. When the Arlington Central School District decided to expand its athletic facilities about 15 years ago, the construction invaded some of the swamp, Pregnall says. Because the turtles are classified as “threatened” by the state Department of Environmental Conservation, the school district was prohibited from diminishing the Blandings’ habitat, so some new wetlands were created adjacent to the new athletic fields. But because the Blandings often venture outside the swamp to densely populated areas near a well-traveled road, the turtle population appears to be slowly dwindling.
“The problem for the turtles is that we have filled or drained the wetlands and turned the nearby meadows into cultivated farm fields -- or athletic playing fields as at the high school -- so they experience a much higher and more lethal level of disturbance when looking for nests,” Pregnall says.
More than 50 different Blandings turtles have been sighted over the past 15 years, but Pregnall and his students have been able to locate only about 25 so far this summer. Only four nests were found during the first two weeks of the research, down from six or seven in the same period in past years, Pregnall says.
When the URSI project ends this summer, Pregnall and his students will write a report on their findings and submit it to the DEC. Data will include the number of turtles sighted, the number of eggs preserved and destroyed and the number of hatchlings.
While the students’ research is confirming that the Blandings turtles are facing some daunting challenges surviving in the swamp, Cardillo says she’s seeing some hopeful signs too. “This year we found two new female Blandings, each about 9 or 10 years old,” she says. “This means they were hatchlings that were successfully protected and they survived long enough to be laying eggs themselves. That speaks to the success of this project.”
Photos ©Vassar College-Buck Lewis
Posted Friday, July 12, 2013