Seepage Salamander


Photo Credit: George W. Folkerts

SCIENTIFIC NAME: Desmognathus aeneus (Bishop and Brown)

OTHER NAMES: Cherokee Salamander, Alabama Salamander (used in past when different geographic populations thought to be distinct species or subspecies).

DESCRIPTION: Small (adults = 18-30 mm [0.71-1.25 in.] head-body length) desmognathine salamander. Females average slightly smaller than males. Hind legs more robust than front legs. A light line present from eye to angle of jaw. Fourteen costal grooves and three to five costal folds between the adpressed limbs. Dorsal pattern consists of a longitundinal, dark-bordered stripe beginning on head and continuing to near tip of tail. Edges of stripe may be smooth, jagged, or crenate. A variable dark midline may occur within the stripe often taking the form of a series of dots, a herringbone-like pattern, or a suffusion of dark pigment. Venter cream to light brown and pigmented with blotches, or a smooth distribution of darker pigment usually more intensely developed in the posterior region and dorsum of tail. Differentiated from other species of genus by small size, a mental gland in males that does not project anteriorly beyond the dentary, presence of light oval blotches on dorsum of hind femora, presence in most populations of from one to six light oval patches interrupting the lateral pigmentation and sometimes connected to the dorsal stripe, and a tail that is round in cross-section. Differentiated from closest relative, the pygmy salamander, by slightly larger size, by presence in males of a reniform mental gland that lacks posteriorly projecting extensions, and by often mottled venter.

DISTRIBUTION: West-central Alabama northeast to extreme northwestern South Carolina, western North Carolina, and two counties in southeastern Tennessee (Jones 1982). In Georgia, occurs widely in the Piedmont of western Georgia (Carroll County) and the Talladega Uplands (Haralson County) northeasterly to include the entire Blue Ridge Province. A possibly disjunct population occurs in Georgia near the main body of the distribution. In western Alabama, found in the Fall Line Hills from northern Hale County and southwestern Bibb County north to southern Marion County. All populations in eastern Alabama lie north of the Fall Line and extend from as far south as the eastern edge of Chilton County and central Tallapoosa County northeast to northern Cleburne County. A record from the Ridge and Valley Province in northwestern Calhoun County not verified by additional collections. All other records are from the Piedmont Province.

HABITAT: Moist seepage areas in deciduous or semi-deciduous forests (Harrison 1992). Most seepage sites occupied associated with small streams. Size of seepages varies from less than one meter (3 1/4 feet) to as large as one hectare (0.5 acre). Deciduous leaf litter, mosses, and a characteristic assemblage of herbaceous plants typify most sites. Moisture originates from underground sources in some cases, but often derived from small amounts of flow that occur in trough-like areas adjacent to streams. Conditions in seepages mimicked at the edges of very small streams where species may be abundant in the leaf litter. Conspicuous associated species are isopods (Ligidium), ground beetles (Scaphinotus), and a variety of terrestrial snails, millipedes, mites, springtails, and spiders. Among vertebrates occasionally encountered are the dusky, red, seal, and two-lined salamanders, and the ring-necked snake. Crayfish burrows often emerge under the litter in the seepages. Although in North Carolina, populations occur at sites up to 1,400 meters (approx. 4,500 feet), the highest elevations from which populations are known in Alabama are on the slopes of Cheaha Mountain 750 meters (approx. 2,200 feet). In the southwesterly portion of distribution in Alabama some populations exist as low as 80 meters (approx. 260 feet).

LIFE HISTORY AND ECOLOGY: Although peak egg laying is in late March in the southernmost part of distribution and in late April-early May in the northernmost portions, some females may deposit clutches at almost any time of year. In Alabama, recently deposited clutches have been found February through October. Whether there are distinct spring and fall laying seasons has not been determined. Eggs laid in small depressions. Contrary to some information, laying sites not always associated with moss clumps, although many clutches are. Clutches also found under small soggy logs and sodden leaf litter, and in small stump holes. One clutch found in a rock crevice. Clutches consist of four to 17 eggs. Cream-colored eggs vary from 2.4 to 3.3 millimeters (approx. 0.1 inch) in diameter. Hatching occurs within 40 to 60 days post-laying, and varies with nest temperature. Newly hatched larvae range from 10.5 to 12.5 millimeters (approx. 0.5 inch) total length. Three pairs of external gills without true rami present, but absorbed within a few days. Larvae never enter water. Foods include springtails, mites, and other small arthropods (Donavan and Folkerts 1972). Although never seen above litter during the day, individuals may emerge at night to feed, sometimes ascending vegetation in search of food.

BASIS FOR STATUS CLASSIFICATION: Populations in Alabama have been declining and disappearing at an increasingly rapid rate since the late 1960s. These changes have been mainly associated with anthropogenic changes, primarily destructive forest practices, in seepage habitats. Large tract clearcutting extensively conducted in the state in the 1970s and early 1980s resulted in the conversion of many tracts of deciduous forest to pine monocultures. After clearcutting, flooding may occur as a result of rapid runoff resulting from removal of vegetation. Because seepage sites never flood under flow regimes characteristic of unaltered watersheds, no seepage organisms are adapted to flooding. Also, intensive flooding may completely eliminate habitats by removing litter. During extremely high flows accompanying scour may erode and destroy the intertwined root and rootlet masses that provide structure in the seepage habitats. Sediment deposition is an additional problem. Removal of deciduous overstory and accompanying shade affects seepage habitats in a number of ways. First, it increases evaporation from the ground surface, thus reducing the amount of water supply to the seepages. Second, increased sunlight intensity dries the litter in the seepage habitats, slowing the decay rate, reducing the humidity in the spaces within the litter habitat, and generally creating conditions so dry that many seepage species cannot survive. This affects the salamanders directly, and perhaps more important, greatly reduces the number and diversity of the microarthropods that form their major food source. Conversion of sites in which seepage habitats occur to pine drastically alters the habitats if pine litter replaces deciduous litter. The microarthropod fauna of pine litter in the southern Appalachians is relatively depauperate. Compared with the fauna of seepage sites in which the litter is mainly derived from deciduous sources, the biomass of litter microarthropods is reduced to less than 5 percent of sites with deciduous litter. Slow decomposition rates and increased acidity resulting from pine litter breakdown further exacerbate detrimental changes. Road construction, urbanization, and overcollecting also have been involved in the decline of some populations. Forest road construction creates significant sedimentation as roads are run across small creeks and it often destroys downstream seepages.

Author: George W. Folkerts

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