CHESTER OBSERVER TRIBUNE (New Jersey) 12 October 06 Wood turtles get special attention; Great Swamp refuge project hopes to protect species (Christina Mucciolo)
Harding Twp.: For 10 years, threatened wood turtles went unseen in the vicinity of the Great Swamp National Wildlife Refuge, until a graduate student came across one that had been run over by a car last summer.
That student, Susie Ponce, 27, of Texas, helped trigger a program designed to track and save the threatened wood turtles in the Great Swamp.
In the summer of 2005, Ponce helped Kurt Buhalmann, a professor at Towson (Md.) University to catch, tag with radio transmitters, and track bog turtles at the Great Swamp National Wildlife Refuge, when they came across the dead wood turtle.
"We found a dead wood turtle on one of the main roads in the Great Swamp, and Kurt Buhalmann, who has been doing work at the refuge (Great Swamp) for many summers, recommended I do an artificial nesting habitat for the wood turtles, and I took the idea to the next level," Ponce said on Sunday.
Ponce was participating in the U.S. Fish and Wildlife Service's Student Experience Career Program at the Great Swamp, which allows graduate students to go to school and work, by getting field experience during the summers.
Ponce did her undergraduate study at Texas Agricultural and Mining University in College Station, Texas, and is in her last year at Johns Hopkins University in Baltimore, Md., studying part-time for a master's degree in environmental science. She also is working at the U.S Fish and Wildlife Service Patuxent Research Refuge in Laurel, Md.
With some help from her counterparts at the Great Swamp, including her supervisor, wildlife biologist Mike Horne, she spent last summer, constructing, testing, and monitoring artificial turtle nesting habitats in the swamp to find out more about a species that is endangered in New Jersey, the wood turtle.
"Wood turtles are not on the federally endangered list, but they are species of special concern in New Jersey, as they are on the state's threatened list," Ponce said, "They used to be very abundant, and now the numbers have declined."
Stream degradation is one reason for the declining numbers, as wood turtles require clear water, and Ponce said, with a lot of urbanization and impervious services, the storm water runoff gets into the streams and makes the water murky and unpleasant for the turtles.
Another concern in addition to de-forestation and the nesting habitats, is that some people like to collect wood turtles as pets.
"They are extremely intelligent turtles," Ponce said of the shelled sages who accrue their wisdom over an incredible life span of up to 60 years.
The Project
Ponce said there are several objectives to the project, the first being that there has not been a lot of research done on the nesting habitats of turtles, specifically wood turtles.
By designing and constructing a creative habitat for the biological and ecological needs of the turtles, Ponce said she is trying to find some way to reduce predation on the turtle nest, from fox, possums, and other creatures who eat the turtle eggs. In addition she said the boxes provide an arena to effectively evaluate what types of sub straits turtles like to nest in.
"Each turtle has its own natural substrate, or type of spoil, that they prefer, and we were trying to find what substrate they prefer in order to manage the species in decline," Ponce said.
The artificial nesting habitat is made of four boxes, framed of wood and covered with chicken wire, with about a four-inch hole wide enough for the turtles to enter. Ponce said each box contains a different type of sub strait.
"We chose two substrates that turtles nest in at the refuge, soil and sand, and then we had one box with stone dust and one with dirt and gravel aggregate because we saw turtles nesting on the trails and the roads," Ponce said.
"Initially, we started in one particular area where wood turtles historically nested in the habitat," Ponce said. "We saw a lot of snapping turtles and painted turtles nesting in the habitats."
Typically, Ponce said wood turtles mate twice a year, once in the fall when they go back to their hibernation spots near the streams, and once in the spring right before they begin nesting, laying anywhere from four to seven eggs from mid-May through July. Snapping turtles, on the other hand, can lay up to 20 eggs.
"The peak season for turtle nesting is June, so we do the project then, during the busiest nesting season," Ponce said. "Usually after two months, the eggs hatch in late August and September."
At the end of June, Ponce said they closed the ramp and entrance of the nesting boxes, and then during July they put in pitfalls to catch the hatchlings as they emerged, so they could determine which turtles were there by the number of hatchlings and the amount of scat.
Ponce said the wood turtles start walking towards their hibernation spot in late-October and November, where they stay until the weather starts to warm up in March or April. She said the turtles love to hibernate in the undercut areas along stream banks, amid the roots of large trees.
Although no wood turtles have been spotted in the nesting habitats, Ponce said they have spotted about eight wood turtles in the Great Swamp.
"We were just doing a survey of a stream and we happened to find one and we kept searching," she said. "We tagged four wood turtles with radio transmitters."
Then, one very hot day, Ponce said she found something very interesting while doing her daily check of the moisture and temperature of the substrates in the nesting habitats.
"The soil, which has a high clay content was hard, the stone and the dirt and gravel aggregate was hot, but the sand was dry and wasn't too hot, and a snapping turtle had nested in the sand," Ponce said. "In the beginning I wanted to see what the turtles like and by the end of the summer I realized that it has a lot to do with moisture and temperature."
Ponce said turtles like to nest in places that are open, and are not too wet and not too dry.
"I have another field season with the nesting project next summer, and there are going to be several modifications for next year," Ponce said. "The next thing to look for is to see where they go and the best places to put the structures."
Ponce said she plans on tracking the wood turtles with radio transmitters, collecting them next summer, and putting them in an enclosed nesting habitat structure, instead of a giving the turtles a choice of going in and out of the structures. In addition, she said there are many different decisions that can be made, such as mixing the different substrates for different nesting habitats.
Ponce and others at the Great Swamp plan to continue their project with new innovations next summer, but in the meantime they have broken a 10-year long absence of a species in the refuge.
Wood turtles get special attention