BUCKS COUNTY COURIER TIMES (Levittown, Pennsylvania) 04 August 08 Turtles: Mystery brings researchers to park (Christian Menno)
Lately, times are tough for the American red-bellied turtle.
Its local population numbers are dwindling and colonies of the species, which could previously be found throughout the area, have been isolated to a few specific locations in Pennsylvania.
One such spot is Silver Lake Park in Bristol Township.
That's where Steven Pearson and his team of Drexel University students have tried to figure out the exact reasons for the turtles' troubles. According to Pearson, who is a graduate student at Drexel, and his four colleagues, determining the cause of the problem can lead to the solution.
“We look at a couple things,” Pearson said, as he helped to insert a plastic tube into a recently trapped turtle's throat. “This has to do with examining their dietary intake. We [insert the tube] to flush their stomachs to find out what they've been eating. It's the most grueling part, for sure.”
Aside from a bit of discomfort, the turtles are treated with care by the team as they attempt to gain as much information as they can from each specimen before it is released.
Other tests include taking blood samples and attaching radio transmitters to track their movements.
Distinctive notches are filed into the front edge of the turtles' shells as a way to differentiate them.
Early each morning, the crew boards two canoes and paddles out to check its large netted traps. Last week the volunteers' focus was on Silver Lake, but they have begun to set traps in Magnolia Lake at Bristol Oxford Valley Road and Lakeland Avenue.
The Pennsylvania Fish and Boat Commission and a grant from DuPont are helping to fund Pearson's efforts. The commission has included the red-bellied turtle on its list of threatened species since 1978. The project is a part of Drexel's bioscience department.
Some days are good, Pearson said, and the team catches a good amount of red-bellies, but there is never any guarantee what might be waiting in the 4-foot long traps.
“We've caught fish, we've caught a rat, bullfrogs and eels; even a duck,” Pearson said.
“He just reached in and pulled out a duck like it was normal,” said grad student Julia Stone with a laugh.
Stone is working toward her master's degree and has studied turtle populations through non-invasive visual observation at nearly 50 sites in southeastern Pennsylvania. She said, though, that this type of hands-on work can provide a more accurate assessment of the situation.
The team's findings at Silver Lake are beginning to confirm what it had already suspected. A major cause for the red-bellied turtles' lack of growth can be traced to another species of turtle living in the area.
The red-eared slider, named for its distinctive red markings above its eyes, is a non-native species that was introduced to Pennsylvania wetlands in the 1960s, Pearson said. The team is trying to determine if the two species are competing for food and nesting space.
“Since red-bellies are a threatened species, we are looking for overlapping resources between them and the sliders,” Pearson said. “If there is, then that creates a potential for competition.”
According to Pearson, if competition does exist, there are several options to take.
“If we find that the non-native turtles are impacting the red-bellies negatively, we can suggest to the state to stop the sale of these turtles or to stop bringing them into the area and institute fines for people who release them,” he said. “We can also post educational signs at places like [the Silver Lake Nature Center].”
Despite their progress, however, Pearson understands that there is no quick fix to the problems facing the red-bellied turtles. “If it is determined that the red-eared sliders are the problem, then we will face some questions,” he said. “Should we get rid of them, or separate them, or will it take some more intensive management?
“Or,” he added, “is nature just going to take its course?”
Turtles: Mystery brings researchers to park