Endangered snail survives and thrives following forest fire

Press release: 

Asheville, North Carolina – Wildlife biologists scaled the wall of the Nantahala Gorge on hands and knees – more climbing than hiking the steep terrain – searching for one of the rarest animals in the world in the wake of forest fires that burned through its habitat last winter.

The noonday globe snail was placed on the federal endangered species list in 1978. The only place it was known to exist was a portion of the southern side of the Nantahala River Gorge, in North Carolina’s Swain County.

“The noonday globe snail has the most limited known range of any endangered animal in western North Carolina,” said Jason Mays, a U.S. Fish and Wildlife Service biologist. “When forest fires came through the gorge last winter, people were worried it it may have been driven to extinction. On the face of it, you wouldn’t expect snails to cope too well with forest fire. We discovered the snail not only survived the fire, but it’s found across a much broader swath of the gorge’s southern face than we ever realized.”

Mays led a team of biologists that started searching the gorge in March, looking for signs of snail survival. The biologists timed their searches for the period after the fire burned off leaf litter from the forest floor and before spring vegetation emerged, which made searching for the snails easier than it had ever been. They began finding shells in spots where the snail had never been recorded. As temperatures warmed and spring moisture arrived, biologists began finding live snails too.

What the biologists discovered means the snail is closer to coming off the endangered species list than anyone ever thought possible.  Prior to the fires, snails were known only in a two-mile stretch of the gorge’s southern side. Post-burn searches found the snail to be present in an area around five miles in length and extending to near the top of the ridge.  When the snails emerged from dormancy this spring, biologists focused efforts on identifying specific areas where the snails were found, and tagged snails in the best habitat. Returning multiple times and noting the frequency with which tagged snails were recaptured provided a population estimate of more than 3,000 individuals in one section of the gorge with the best habitat for the snail.

Much of the gorge is part of the Nantahala National Forest, which, combined with the rugged nature of the terrain, means the snail’s habitat is largely protected from development. A lingering question was how the snails would fair through a forest fire. Their success in the wake of recent fires makes Service biologists optimistic.

The Nantahala Gorge is one of the few outcrops of calcium-rich rocks and soils in western North Carolina, ultimately providing the calcium the snails need to make shells. The steep topography also contributes to snail success. The noonday globe has a strong preference for very damp habitat, and a preliminary review of satellite photos of the gorge at different times of day strongly suggests that the snail is only found in places where shade exists for most of the day.