© 2012 Todd Pierson (1 of 21)
Desmognathus aeneus Brown and Bishop, 1947
Julian R. Harrison1
1. Historical versus Current Distribution. Seepage salamanders (Desmognathus aeneus) are distributed locally in southwestern North Carolina, southeastern Tennessee, northern Georgia, and north-central Alabama (Harrison, 1992; Conant and Collins, 1998; Petranka, 1998). Western populations in the Fall Line Hills region of Alabama are separated by an apparent hiatus from eastern populations of that state in the Blue Ridge and adjacent Piedmont regions. Another apparently disjunct population is present in the Piedmont of northeastern Georgia. Camp and Payne (1996) recorded a slight extension of the range in Georgia, and Livingston et al. (1995) provided the first record for the species in northwestern South Carolina. Despite statements to the contrary (Harrison, 1967; Petranka, 1998), seepage salamanders do occur north of the Little Tennessee River, as a population is known in the Hazel Creek area of Great Smoky Mountains National Park (R. Highton, personal communication).
2. Historical versus Current Abundance. Few historical data are available. Folkerts (1968) found seepage salamanders to be abundant within their habitat in Alabama. For example, in an estimated 65 square feet of suitable habitat in Clay County, 131 specimens were collected. The writer’s experience with this species in Georgia and North Carolina during 1958–'62 was similar. The salamanders were common to abundant at virtually all localities visited. On one occasion in Union County, Georgia, 64 specimens were collected within a 2-hr period from beneath leaf litter and mosses along a small stream.
3. Life History Features.
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. Unknown as such, but females move from beneath leaf litter retreats to the vicinity of streams and seepage areas to lay eggs. Courtship and mating behavior are unknown, except in laboratory studies (Promislow, 1987). There is a striking similarity between the courtship of this species and that of D. wrighti (pygmy salamanders; Verrell, 1997, 1999).
In Alabama, clutches of eggs are found from early February to late May, but most oviposition in west Alabama occurs in February and March (Valentine, 1963c; Folkerts, 1968). In east Alabama, most clutches are found in April, and there is also a fall oviposition period with egg deposition occurring from mid July to early October (Folkerts, 1968). In Georgia and North Carolina, oviposition occurs during late April to early May; hatching takes place from late May to early August (Harrison, 1967). In Tennessee, oviposition occurs from late April to early May and hatching from mid June to mid July (Jones, 1981).
ii. Breeding habitat. Forest floor in seepage areas.
i. Egg deposition sites. Eggs are deposited under mosses, logs, leaf litter, and root mats or other objects in seepage areas or near streams (Valentine, 1963c; Harrison, 1967; Folkerts, 1968; Jones, 1981).
ii. Clutch size. Females lay 3–19 eggs (Bishop and Valentine, 1950; Harrison, 1967; Folkerts, 1968; Jones, 1981; Beachy, 1993a; Collazo and Marks, 1994). For a description of eggs, see Brown and Bishop (1948); for a staging table, see Marks and Collazo (1998).
C. Direct Development. The developmental period of laboratory clutches lasts an estimated minimum of 60 d (Valentine, 1963c) or 34–45 d (Harrison, 1967). In field clutches in Tennessee, approximately 45 d elapsed between the earliest date observed for uncleaved eggs and the earliest date observed for hatching (Jones, 1981).
D. Juvenile Habitat. Same as adults. This species is terrestrial; there is no free-living aquatic larval stage. Seepage salamanders were included in a key to salamander larvae and larviform adults (Altig and Ireland, 1984), probably because of the presence of short, unpigmented gills and a partial dorsal fin in some hatchlings. Though, as the authors note, they probably never enter the water.
E. Adult Habitat. Adults are terrestrial and live at the interface between the leaf or leaf mold layer and the underlying soil in the vicinity of seepages and small streams in heavily shaded hardwood or mixed forests (Harrison, 1967, 1992; Folkerts, 1968; Jones, 1981; Hairston, 1987; Bruce, 1991). When active, adults are nocturnal (Brandon and Huheey, 1975), typically remain under surface cover, and are not known to climb or actively burrow (Harrison, 1967; Folkerts, 1968; Jones, 1981; and Hairston, 1987). One apparent exception to the lack of scansorial activity by this species was given by Wilson (1984), who observed seepage salamanders climbing on grasses and bushes and jumping from branch to branch at a locality in central Alabama. Harper and Guynn (1999) studied the factors affecting salamander density and distribution within four forest types in the Southern Appalachian Mountains. They found that seepage salamanders and other salamanders preferred moist microsites within each forest type, with the highest densities occurring on sites with a northern and/or eastern exposure and within northern hardwood forests. They noted that densities were lowest on 0–12-yr plots but equal on 13–39 and ≥ 40-yr plots, suggesting a quicker recovery from clearcutting than reported by previous researchers. As plots with salamanders had significantly higher numbers of snails than plots without them, the authors also suggested that snails may be a necessary source of calcium for salamanders and may have a substantial impact on salamander distribution.
F. Home Range Size. Unknown.
G. Territories. Unknown. However, under laboratory conditions seepage salamanders displayed little or no aggression toward conspecifics or heterospecific Allegheny Mountain dusky salamanders (D. ochrophaeus) and pygmy salamanders (Peele, 1992).
H. Aestivation/Avoiding Dessication. Seepage salamanders do not aestivate; major activity occurs in the spring and summer, but individuals can be observed during any time of the year.
I. Seasonal Migrations. Unknown, but probably do not occur. The possible exception is the movements of females to oviposition sites within seepage areas in late spring and early summer.
J. Torpor (Hibernation). Unknown.
K. Interspecific Associations/Exclusions. Seepage salamanders are sympatric with pygmy salamanders in the vicinity of Deep Gap and Wayah Bald, Macon County, North Carolina, and the two species also occur in close proximity in forest floor habitats along the Nantahala River, North Carolina (Tilley and Harrison, 1969; Rubin, 1971; Bruce, 1991). At most known localities within its range, seepage salamanders coexist with one to several other congeneric species, though not completely syntopically. Where studied in the Nantahala and Unicoi mountains, they occupy the forest floor habitat, occurring farther from streams or seepages than other species (Hairston, 1973; Jones, 1981). Seepage salamanders are extremely secretive, apparently unaffected by competitive or predatory interactions with sympatric, congeneric seal salamanders (D. monticola) and Allegheny Mountain dusky salamanders (Hairston, 1987). Hairston speculated that this is perhaps attributable to an original predatory relationship that is no longer detectable. Sever et al. (1976) list seepage salamanders as an associate of Junaluska salamanders (Eurycea junaluska) in Graham County, North Carolina.
L. Age/Size at Reproductive Maturity. Both sexes reach sexual maturity at 18–19 mm SVL (measured to anterior margin of vent) at 2 yr (Harrison, 1967).
M. Longevity. A wild-caught specimen in the Cincinnati Zoo survived 4 yr, 14 d (Bowler, 1977). Survivorship in nature is unknown.
N. Feeding Behavior. Arthropods are the principal foods, primarily insects, but arachnids, isopods, amphipods, centipedes, millipedes, nematodes, earthworms, and land snails are also eaten (Folkerts, 1968; Donovan and Folkerts, 1972; Jones, 1981). Donovan and Folkerts (1972) also reported the occurrence of a recently hatched seepage salamander in the stomach of a small adult male. Most of the items consumed are leaf litter species, indicating the confinement of foraging activity to that microhabitat rather than the forest floor surface (Jones, 1981).
O. Predators. Unknown, but individuals could be preyed upon occasionally by large sympatric Desmognathus of other species, spring salamanders (Gyrinophilus sp.), ring-necked snakes (Diadophis punctatus), and possibly species of birds that forage in leaf litter. Folkerts (1968) listed ring-necked snakes as an associate of seepage salamanders in his study of Alabama populations.
P. Anti-Predator Mechanisms. Most individuals attempt predator avoidance by remaining immobile when exposed, primarily in a linear posture (Dodd, 1990a; personal observation).
Q. Diseases. Unknown.
R. Parasites. Unknown.
4. Conservation. There is evidence that logging activities are responsible for the extirpation of some Alabama populations (Folkerts, 1968). In that state, seepage salamanders are currently ranked as S2, Imperiled because of rarity (6–20 populations) or vulnerability to extirpation (Alabama Natural Heritage Program, 1996). Approximately half of the populations known in 1976 no longer exist, primarily because of various forestry practices (G.W. Folkerts, personal communication). The species’ present status in North Carolina is SR (Significantly Rare) with a rank of S3, Rare or Uncommon (21–100 extant populations; LeGrand and Hall, 1995). At present, however, populations appear to be stable and the species is common locally (R.C. Bruce, personal communication). Hairston and Wiley (1993) conducted identical observations 1–4 times per year for 15–20 yr at two locations in the southern Appalachians that showed fluctuations in numbers but no trend among several salamanders species, including seepage salamanders. Georgia accords seepage salamanders no legal status but ranks them S3 (Georgia Natural Heritage Program, 1996). Three populations in Stephens and Union counties, Georgia, monitored by Carlos Camp (personal communication) appear to be stable, but these have incidental protection either because they exist in areas set aside as special botanical areas or occur adjacent to the Appalachian Trail. In Tennessee, seepage salamanders are regarded as a species in need of management and are ranked S1, "Extremely Rare and Critically Imperiled with five or fewer occurrences, or very few remaining individuals, or because of some special condition where the species is particularly vulnerable to extinction” (Withers, 1996). The U.S. Fish and Wildlife Service (1994c) listed seepage salamanders as a Category 2 candidate for listing. However, a more recent list (U.S. F.W.S., 1996a) removed that classification.
Maintenance of wide buffer zones adjacent to seepages and streams would protect this species’ habitat (Wilson, 1995).
1Julian R. Harrison
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Nov 2018.
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