Conserving an ancient resident of Virginia’s New River
The endangered Virginia fringed mountain snail (Polygyriscus virginianus) is a relic of a chilly past—left on the Appalachian river banks in Virginia after the glaciers receded, it’s the last surviving species in its genus.
The snail was thought to be extinct when it was first described via fossil in 1948. Then, in 1971, the first living specimen was documented, leading to the protection of the species under the Endangered Species Act in 1978.
Between 1971 and 1986, just 27 living snails were documented along a 230-foot (70-meter) stretch of the New River’s western bank in southwestern Virginia, just south of Blacksburg. And then the species went missing again for over two decades. This was likely due to the rarity of the species, but can also be attributed to their small size of just 1/64 of an inch (four millimeters)—the length of a red ant. The snail also spends much of its life burrowed up to six inches (15 centimeters) deep in the soil and loose limestone fragments of the New River’s bluffs.
The species’ recovery plan, finalized by the U.S. Fish and Wildlife Service (Service) in 1983, identifies the maintenance and widening of the nearby Wilderness Road, as the primary threat to the snail. Disturbing its limited habitat would put the fragile population at risk.
This impending threat prompted Ken Hotopp of Appalachian Conservation Biology, an organization specializing in land snail research, to inventory the land snail in the Lower New River Corridor, with support from the U.S. Fish and Wildlife Service and local landowners granting access to the habitat. According to Mike Drummond, a fish and wildlife biologist in the Service’s Virginia Ecological Services Field Office, this was the most comprehensive survey completed to date.
This surveying effort, which began in 2009, not only led to the rediscovery of the species, but also yielded evidence that the species may have a wider distribution than previously thought.
In the two years of work, the survey collected 375 Virginia fringed mountain snail shells. Because these shells were freshly deposited in the limestone, researchers were able to map out the land snail’s unique habitat across the six miles (10 kilometers) of steep river slopes. And on the final day of the inventory, for the first time since 1986, researchers found a living Virginia fringed mountain snail in an unexpected location, outside of the species’ known range. Before this long awaited discovery, biologists feared the species might have been extinct.
“It’s a unique challenge, when you’re dealing with an animal that’s so small and usually burrowed underground. You’re talking about finding a needle in a haystack—worse actually,” says Drummond. “The fact that we found one is amazing.”
The survey was groundbreaking, redefining biologists’ understanding of the Virginia fringed mountain snail’s distribution. Uncovering the new upper range boundary expanded the species’ known habitat by 50 percent.
Researchers also learned that the primary place where the snail occurred had become a quarry, with little evidence of snails remaining. And when the New River was dammed and flooded to make Claytor Lake, it washed away part of its remaining habitat. With its habitat now further marginalized, hope for the species’ future came when plans to modify Wilderness Road were cancelled.
“We dodged a bullet there,” says Drummond.
Surveying efforts will continue in an attempt to further refine knowledge and understanding of the snail’s range and its habitat. Land purchase or conservation easement will be an important future step in protecting the species on the western bank of New River. For now, the population here is likely to be left alone—with the quarry now inactive and Wilderness Road seldom trafficked, there is no threat of disturbance to the area in the foreseeable future. …Finish reading the story on the Bulletin’s website!