Noonday Snail

Mesodon clarki nantahala

Description

The noonday snail, Mesodon clarki nantahala, has a rounded shell with five and one-half whorls and a depressed spire. It measures about 0.72 in (1.8 cm) in width and 0.44 in (1.1 cm) in height. The glossy red shell is sculptured by coarse bands.

Behavior

This snail is most active during wet weather and is presumed to feed on fungi. It is found in thick tangles of vegetation, beneath rocks, or in deep, moist leaf litter. Reproductive behavior and other aspects of its life history have not been adequately studied but it is believed that the noonday snail is hermaphroditic and prefers copulation to self-fertilization. The noonday snail appears to migrate seasonally, moving from the gorge cliffs to cavities within the cliff.

Habitat

The noonday snail is found in a damp oak-hickory woodland with a profuse, herbaceous undergrowth. It is particularly common along cliffs with a northern exposure. This area of rock outcroppings and rich, humus-laden soils supports a complex plant community. The habitat is kept moist year round by an abundance of springs, seepages, streams, and waterfalls. The elevation rises steeply from 1,900 to 3,100 ft (580-945 m). Dominant trees include oak, hickory, American beech, American elm, basswood, birch, and tulip poplar. Rhododendrons and many species of ferns are prominent components of the undergrowth. In recent years, non-native plants such as kudzu and honeysuckle have invaded the habitat.

Distribution

Woodland snails of the genus Mesodon are common throughout the eastern United States, displaying the greatest diversity in the southern Appalachians. The noonday snail was historically confined to an area of southeastern Tennessee, extreme western North Carolina, and northern Georgia. The noonday snail is found in the Nantahala Gorge in North Carolina, along the high cliffs that line the southern banks of the Nantahala River. The portion of the gorge inhabited by the snail extends for several miles along the river near Blowing Springs from Wesser to Hewitt (Swain County). Most of the habitat falls within the boundaries of the Nantahala National Forest. No estimate of the size of the population has been attempted because of the ruggedness of the terrain.

Threats

The noonday snail is restricted to a narrow section of the Nantahala Gorge and is adapted to very specialized conditions of moisture and temperature. Any degradation of the habitat would result in the decline of this species. In recent years, the gorge has become a popular site for canoeing, kayaking, hiking, climbing, and camping. Several camping areas are located close to the habitat. This recreational traffic increased the risks of trampling, forest fires, or other disturbance.

Conservation and Recovery

Because the noonday snail is found on public land, protecting its habitat has been relatively straightforward. The Forest Service and the state of North Carolina devised a cooperative habitat management agreement and are conducting further research into the snail's biology. Recreational access to critical portions of the habitat is now closely regulated, and similar habitats along the Nantahala River are being surveyed to determine if other populations of the snail exist.

Contact

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

References

Roe, C., and J. Moore. 1983. "Recommendations to the U.S. Forest Service Regarding the Designation of the Noonday Snail's Primary Habitat as a Protected Natural Area." Report. North Carolina Department of Natural Resources and Community Development, Raleigh.

U.S. Fish and Wildlife Service. 1984. "Recovery Plan for the Noonday Snail (Mesodon clarki nantahala )." U.S. Fish and Wildlife Service, Atlanta.