When a species is listed as endangered or threatened, there are usually many causes. The same goes for the western pond turtle. Washington Department of Fish and Wildlife biologist David Anderson says he believes the turtle’s main problem began as dams were put in place. He says it’s the one major change that’s taken place in the Columbia River Gorge over the years.
“If you look at historic aerial photos of the area, you can see that there historically were backwater slews, channels, small ponds and seasonal wetlands that we assume were used more by pond turtles during that time period,” he says. “So we think that when the hydro system was put in, and the river was turned more into a lake system in this part of the gorge, that maybe a lot of those turtle populations moved upland.”
Another threat to western pond turtles is non-native bullfrogs. It’s all a numbers game, says Frank Slavens, the reptiles curator at Seattle’s Woodlands Park Zoo, now retired.
“You get to a point where you don’t have enough adults producing enough babies to sustain the population,” Slavens says. “That’s where we were at with the western pond turtles. They breed, they have babies, but the babies go into the water and the bullfrogs eat them all. Twenty years of that, and your old turtles start to die, you don’t have any young ones coming up to replace them, and you start running out of turtles.”
Populations are now growing, mainly thanks to the Head Start program started in 1990 by Slavens.
“We developed a program to put translators on wild females, track the females and find their nests when they nested, wait for the nests to hatch and then take the babies to the Woodland Park Zoo and later the Portland Zoo,” Slavens says.
At the zoos, the babies would feed and grow rather than hibernate all winter long. That way they had less chance to be eaten by bullfrogs in the spring. When the program first began, there were 150 western pond turtles. Twenty years later there are 1,600.
“We’ve got more Head Started females that are nesting than we had turtles when we first started,” Slavens says.
Share your experiences as part of EarthFix's Public Insight Network.
Join our Public Insight Network!