Southern Discomfort: A Local Species Faces Global Challenges
By Amy Mathews Amos
“It’s a rattlesnakey kind of day,” says Tom Akre as he guides his pickup truck along a dusty gravel road in George Washington National Forest near the Virginia–West Virginia border. That’s not a good thing. It’s late May—quite late for nesting wood turtles. They usually start nesting by the middle of the month. But the cold and snow of multiple polar vortexes delayed spring this year. So far, none of the 55 female turtles in Tom’s study area has dug a hole and deposited her clutch of eggs.
On this day, the weather is finally glorious—sunny, low humidity with temperatures in the low 70s. Good for rattlesnakes and people, but not for turtles. Too much sun, and they overheat. Too dry, and they desiccate. At this point in the year most females are heavy with eggs. But unless the conditions are just right they’ll stay put, hiding under leaves in forest glades or retreating to the cool streams.
Tom is a wildlife ecologist at the Smithsonian Conservation Biology Institute in Front Royal, Va., who has agreed to let me shadow him for a day in the field. He’s an easy-going guy with cheerful blue eyes and a ready smile under his light brown beard, and he guides his six field assistants—all young interns and graduate students—with a friendly firmness that keeps them on track. But his research subjects are finicky.
We spent the morning searching for turtles along the Forest Service road, the hillsides rising up from it, and the creeks flowing beside it. Tom and his crew have placed radio transmitters on many of the females to track them as they migrate from the streams where they hibernate to the spots they ultimately choose to lay their eggs. Their radio transmitters can send signals up to a mile away, but those signals often bounce off the walls of the steep hillsides. Today, the clicks on the radio receiver have lured us repeatedly up steep slopes only to send us bushwacking back down again when the signal shifts to the valley below. So far, we’ve found four turtles. Some by following those confusing radio signals until they finally zero in on a female. Others—such as the big guy nicknamed “Ultra-male”—by simply searching the ground around moist seeps where turtles feed. Despite the bright orange coloring on their legs and necks, wood turtles are surprisingly hard to spot.
But it’s now mid-afternoon, and we haven’t seen any nesting females. And although I’ve been relishing the sunny weather as I traipse through the forest with Tom and his crew, everyone else has been hoping for rain. Just the right amount of rain at the right temperature should break the nesting bottleneck, prompting a slew of ready females to move out of the seeps where they feed and onto the sandy banks where they nest. The right amount of rain will moisten the soil making it easy to dig. The right temperature will keep the cold-blooded turtles active. We need, literally, the perfect storm.
Eastern West Virginia and Rockingham and Augusta counties in Virginia mark the southern extent of the wood turtle’s range. In a world that’s growing warmer, that’s bad news if you’re a turtle. A recent study in the scientific journal PLoS One found that many North American turtles are at risk from climate change. Evidence from past ice ages suggest that the rate of change today is too fast for turtles to shift their geographic ranges and find new suitable habitat. Wood turtles live throughout the northeastern United States from Maine to Virginia, but they’re at risk everywhere. Their far-ranging and finicky habits—searching for just the right locations to hibernate, feed and nest—make them vulnerable to development throughout the region. And their pretty orange legs and neck make them attractive as pets. Poachers illegally catch wood turtles and sell them to collectors for hundreds of dollars each. In fact, when I first arrived at the forest that morning, Tom made me promise not to reveal the study site’s location. “The last thing we want to do is tell dealers where they can find turtles,” he said.
The International Union for the Conservation of Nature, which monitors the status of wildlife globally, considers wood turtles endangered. The states of Virginia and West Virginia both have officially listed wood turtles as a species of greatest conservation concern. And biologists from state wildlife agencies, universities and conservation groups throughout the Northeast are now coordinating their research efforts to keep wood turtles off the federal endangered species list. As part of that, Tom and his crew are trying to understand why wood turtles choose some locations over others, and whether those choices are actually good in a world that is vastly different from the one in which they evolved.
Eons ago, wood turtles in the Shenandoah and Potomac valleys probably could have met all their needs within a pretty small area. They could nest each spring in the soft sandy banks that form along bends in the river and nearby tributaries. They could feed in the adjacent forest, which had just enough shade to prevent overheating and—thanks to occasional flooding that culled some of the trees—just enough sunlight for tasty plants to grow along the ground. Because their nests were so close to the water, their tiny offspring wouldn’t have far to go before reaching the relative safety of the stream. In winter, they could avoid the worst of the flooding by hibernating in smaller side streams, less likely to wash them away in severe storms. If some populations did get washed out, there were plenty of others elsewhere to recolonize the site the next year.
Today it’s different. Houses, farms, and roads hug rivers and creeks, not sandy beaches. The surrounding landscape isn’t a turtle-perfect blend of patchy forest, either. Instead, it’s suburban lawns, cow pastures, and farm fields. After spending the winter hibernating in a small stream, wood turtles head out each spring in search of food and nest sites, sometimes covering miles in their search when they don’t find the right conditions nearby. Graduate student Jeff Dragon spelled out the reality bluntly for me that morning. “If you apply that to Clarke County or even Fairfax where they used to live—you take a turtle from a creek and draw a line two miles around from the point where they’re nesting—you’ll see that they’re going to have to cross six roads. And then they have to come right back and cross those six roads again [on their return]. They might make it this year, they might make it next year, but they normally would live 60 or 70 years, and they only replace themselves a few times in that life span. So when a turtle like that gets hit, it’s going to cause extinction really fast.”
At the ripe old age of 27, Dragon feels like he’s already seen this happen in South Jersey where he grew up. He was a turtle fanatic as a kid, spending his summers catching box turtles and transplanting them around his neighborhood for fun. But at some point the turtles disappeared. He blamed the development boom of the 1990s and decided to study turtle conservation in college. He’s been tracking the survival rate of wood turtle hatchlings for his Master’s Degree at George Mason University and working closely with Akre to understand how turtle choices and human activities affect that survival.
Looking for Answers
Traffic is minimal in the National Forest where the team works, but the Forest Service’s gravel roads affect turtles in other ways. We’re in the mountains, and the small forest streams here generate few, if any, sandy banks. Instead, the most obvious open banks occur along the twisty dirt road. After tracking females in his 12 square-mile study area for years now, Akre has a good idea of which banks attract nesting wood turtles. “That’s Queen’s Bank,” he says as we bump along the road in the hot sunshine, so named for an assertive female nicknamed Queen who frequently nests there. But we see no sign of her. Presumably, she’s waiting for this afternoon’s predicted rain shower.
Tom points out other roadside banks where wood turtles often nest as well. But his research is revealing that, despite their superficial similarity to idyllic riverside beaches, these nest sites often don’t turn out well. For one thing, they’re not alongside the water. So once hatched, baby turtles no bigger than an Oreo cookie might have to travel overland hundreds of yards or more to get to the stream’s safety. Along the way, they’re an easy target for raccoons and other predators. But many nests don’t even last long enough for the hatchlings to attempt their maiden trek to the stream. Predators find the eggs and eat them before they hatch. Or the soil along the banks prevents adequate drainage, and the eggs get waterlogged. Akre wonders if these forest roads inadvertently create ecological traps, luring females with their open beach-like exposure, but poorly mimicking the conditions their offspring need to survive.
So he’s gathering data to find out. His research is funded by the Virginia Department of Game and Inland Fisheries with in-kind support from the U.S. Forest Service and the Smithsonian Conservation Biology Institute. Once focused almost exclusively on captive breeding of endangered, often foreign, wildlife as an arm of the National Zoo, the Institute has expanded its work in recent years to address wildlife conservation in Virginia as well. That includes working with private landowners through the Virginia Working Landscapes Program, and partnering with George Mason University to provide students with hands-on internships and graduate fellowships. That partnership has provided Akre with all six of his crew members here today.
Together, they’ll find about 40 wood turtle nests in this section of the forest. They’ll protect half the nests from predators and measure just about everything they can think of that might make these sites attractive to a nesting wood turtle or affect the survival of her offspring: The type of soil and its temperature over the summer, nearby vegetation, the direction and angle of the slope, and the distance of the nest from the closest water. When the eggs hatch in August, the team will attach mini transmitters to the hatchlings’ tiny shells, and track them for at least 80 days to see how they fare.
They’ll leave the remaining nests unprotected and set up cameras that automatically snap photos of any warm-blooded creature that moves nearby. Predation is high for turtles just about everywhere. But Akre cites scientific studies showing that predators are more successful when they hunt along straight lines—such as trails or dirt roads—than they are by simply searching around in the mosaic of natural landscape. Dragon goes even further. “They learn,” he told me that morning. “They know to run these roads during this time of year. They think ‘oh May and June, it’s time to get those eggs.’”
Here at the southern end of the wood turtle’s range, a warming climate could soon become another problem. Akre’s not yet sure why wood turtles don’t extend any farther south, but he thinks it might be related to high summer temperatures drying out nests. Those temperatures are expected to get even higher in coming decades. At a recent conference on climate change in West Virginia, state climatologist Kevin Law predicted that the number of days exceeding 95 degrees in a typical year could increase from 0 to 10 days now, to 5 to 30 days by mid-century. He also expects extreme rainfall events to increase. Today, about 7 to 11 days experience more than an inch of rain each year. In 50 years, that could be 8 to 12 days. Flooding from extreme weather can wash away turtles and wipe out nests: Just two weeks previously, flooding from a heavy mid-May rainstorm killed one of the team’s turtles.
The team has split up this afternoon—I’ve joined Akre and his project manager Ellery Ruthie, while Dragon led two interns in another section of the forest. It’s now time to check in and compare notes. Akre slides the pickup in front of a compact car with New Jersey plates parked alongside the road and we find Dragon’s group in the nearby forest. They tell us they’ve found several turtles in the area, but none nesting. Above us, the sky starts to darken and thunder rumbles in the distance. But the crew is too jaded to pin much hope on it. The turtles should have been nesting for days now; the crew scrambling to keep up. Every day they’ve expected this to be the day, only to be disappointed. Suddenly the clouds let loose and large cool drops splatter on all of us. We’re quickly getting drenched and rush back to the cars for rain gear and temporary cover.
No one expects the turtles to respond immediately—it could take a half hour or more for the rainfall to actually loosen up the dry soil. Tom drives down the road on the lookout anyway. He doesn’t get very far: There in the middle of the road, mere minutes after the cloudburst, is the turtle known simply as number 403 heading steadily towards the sandy bank on the other side.
We spot three more nesting females that afternoon, all of them in the exposed banks sloping uphill along the Forest Service road, plus one more in the forest still waiting for just the right time. Number 403 isn’t quite ready to dig, and Ellery places a radio transmitter on her so the team can track her in coming days. Number 705 is testing out the soil when we spot her, trying to determine if she found a good spot. Number 708, nicknamed Cracky for the obvious crack on her shell, is digging her nest. And number 96 is finishing up, packing in the dirt to protect her just-laid clutch.
I decide to pack it in myself. It’s six o’clock in the evening and I’m wet and chilled from wading through creeks, hiking through seeps, and searching for turtles in the rain. Now that the action has started, the crew has a long night ahead of it. I flick yet another tick off my arm and head out, hoping that the site is secure, the turtles choose wisely, and the weather—now and in the future—cooperates.
Amy Mathews Amos has worked at the interface of environmental science and public policy for 25 years as an analyst, advocate, consultant and now writer. Her writing has appeared in The Washington Post, Pacific Standard, Earth Touch News Network and elsewhere. She serves on the boards of the American Conservation Film Festival and Marine Conservation Institute, and blogs for The Downstream Project at thedownstreamproject.org. Follow her on Twitter