Southern Gray-cheeked Salamander, Southern Graycheek Salamander
© 2014 Todd Pierson (1 of 8)
Country distribution from AmphibiaWeb's database: United States
Plethodon metcalfi Highton and Peabody, 2000
David A. Beamer1
1. Historical versus Current Distribution. Southern gray-cheeked salamanders (Plethodon metcalfi) are found in the southern Blue-Ridge Mountains, including Haywood and Macon counties, North Carolina, and Oconee County, South Carolina, at elevations above 750 m to the limits of large tree growth. One population occurs at an elevation of 256 m, the lowest elevation known for the entire P. jordani complex (Highton and Peabody, 2000). A portion of their original distribution is now underwater, covered by Lake Jocassee (Highton and Peabody, 2000).
2. Historical versus Current Abundance. Generally unknown, but of four sites sampled by Highton (2003) prior to 1990 and resurveyed in the 1990s, numbers of animals observed at three sites were lower, and at two of these sites numbers were substantially lower. Further sampling will be necessary to determine whether these data reflect true declines or natural population fluctuations. Southern gray-cheeked salamanders disappeared from clearcut areas in Macon County, North Carolina, within four years of lumbering (Ash, 1988, 1997).
3. Life History Features.
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. Unlikely; breeding migrations are unknown in any Plethodon species.
ii. Breeding habitat. Unknown.
i. Egg deposition sites. Unknown, but likely to be in underground cavities.
ii. Clutch size. Unknown.
C. Direct Development.
i. Brood sites. Unknown.
ii. Parental care. Unknown, but it is likely that females brood, as with other species of Plethodon.
D. Juvenile Habitat. Juvenile southern gray-cheeked salamanders (17–25 mm SVL) from Macon and Jackson counties, North Carolina, were collected from 12–14 July. They were flushed from wet leaf litter within a cave-like opening and also were found in wet leaves at or above their intersection with loam. At night, juveniles were found on rock faces near the intersection of stone and leaf litter, and on rainy nights they were found on the leaves of herbaceous vegetation ≤ 30 cm above ground (Gordon, 1960).
E. Adult Habitat. King (1939) found southern gray-cheeked salamanders beneath logs in oak-chestnut forest in areas having good deep soil.
F. Home Range Size. Adult male southern gray-cheeked salamanders in the Balsam Mountains have an average home range of 5.04 m2. Adult females have an average home range of 1.87 m2. Two and three year olds have average home ranges of 1.52 m2 and 2.98 m2, respectively (Nishikawa, 1990).
Experimentally displaced animals are known to climb trees immediately after being released, presumably to enhance olfactory cues (Madison and Shoop, 1970; see also Petranka, 1998; original observation recorded under P. jordani, but probably based on P. metcalfi [R. Highton, personal communication]).
G. Territories. At least some members of the Plethodon jordani complex aggressively defend territories (Thurow, 1976); it is unknown whether southern gray-cheeked salamanders establish and defend territories.
H. Aestivation/Avoiding Dessication. Large series of southern gray-cheeked salamanders have been collected in Macon County, North Carolina, from mid August to early September (Houck et al., 1998).
I. Seasonal Migrations. Unknown.
J. Torpor (Hibernation). At lower elevations, animals remain active during warmer winter weather, retreating during freezes (see Petranka, 1998; original observation recorded under P. jordani, but probably based on P. metcalfi [R. Highton, personal communication]).
K. Interspecific Associations/Exclusions. In the Balsam Mountains, the following species were encountered on experimental plots with southern gray-cheeked salamanders: black-bellied salamanders (Desmognathus quadramaculatus), seal salamanders (D. monticola), Ocoee salamanders (D. ocoee), pygmy salamanders (D. wrighti), southern red-backed salamanders (Plethodon serratus), southern Appalachian salamanders (P. teyahalee), spring salamanders (Gyrinophilus porphyriticus), red salamanders (Pseudotriton ruber), Blue Ridge two-lined salamanders (Eurycea wilderae), and eastern newts (Notophthalmus viridescens; Hairston, 1980b, 1981).
Hairston (1949) reports the following salamanders along with southern gray-cheeked salamanders from near Highlands, Macon County, North Carolina: black-bellied salamanders, seal salamanders, Ocoee salamanders, and red salamanders. Southern red-backed salamanders, southern Appalachian salamanders, and Blue Ridge two-lined salamanders also are found in this area and are often closely associated with southern gray-cheeked salamanders (Ash, 1997).
Southern Appalachian salamanders are widely sympatric with the Blue Ridge, Balsam, and Cowee isolates of southern gray-cheeked salamanders. There is no evidence of hybridization except at one site along Alarka Creek in the northern Cowee isolate where there is considerable hybridization (Highton and Peabody, 2000).
White-spotted slimy salamanders (P. cylindraceus) are sympatric at the eastern edge of the Blue Ridge isolate of southern gray-cheeked salamanders. There is no evidence of hybridization between these species (Highton and Peabody, 2000).
An unusual association of large eastern Plethodon occurs in the vicinity of Rabun Bald, Rabun County, Georgia. Here there is a wide hybrid zone between southern gray-cheeked salamanders and a member of the P. glutinosus complex, Atlantic Coast slimy salamanders (Plethodon chlorobryonis). In this same area, Atlantic Coast slimy salamanders are also sympatric with southern Appalachian salamanders, another member of the P. glutinosus complex, and there is no evidence of hybridization between these species. Thus two members of the P. glutinosus complex contact without hybridization in the same area in which one of them (Atlantic Coast slimy salamanders) hybridizes with a member of the P. jordani complex (Highton and Peabody, 2000).
Southern gray-cheeked salamanders contact Jordan's salamanders (P. jordani) on Balsam Mountain and on Hyatt Ridge. Narrow hybrid zones are present at both contact zones (Hairston, 1950; Highton, 1970; Hairston et al., 1992; Highton and Peabody, 2000).
Southern gray-cheeked salamanders may contact Blue Ridge gray-cheeked salamanders (P. amplus). Their geographic and genetic interactions have not been analyzed (Highton and Peabody, 2000).
Hairston (1980b, 1981) demonstrated competition between southern gray-cheeked salamanders and southern Appalachian salamanders in the Balsam Mountains. The number of southern Appalachian salamanders increased significantly at plots in the Balsam Mountains where southern gray-cheeked salamanders were removed. The removal of southern Appalachian salamanders from plots resulted in a substantial increase in the proportion of young southern gray-cheeked salamanders. Hairston (1980b, 1981) did not identify which resources are limiting but hypothesizes that southern Appalachian salamanders may compete with members of the P. jordani complex for nesting sites.
In a portion of the Balsam Mountains, North Carolina, southern gray-cheeked salamanders and southern Appalachian salamanders replace each other altitudinally. In one transect there is no elevational overlap, while in two others there is overlap of 15 m and 46 m. However, in another section of the Balsam Mountains, the two species occur together over a wide elevational range with an overlap of 457–594 m (Hairston, 1951).
L. Age/Size at Reproductive Maturity. Males reach sexual maturity about 3 yr after hatching, at a size of about 50 mm SVL (Howell and Hawkins, 1954; original observation recorded under P. jordani but probably based on P. metcalfi [R. Highton, personal communication]).
M. Longevity. Unknown.
N. Feeding Behavior. In captivity, southern gray-cheeked salamanders fed on waxworms (lepidopteran larvae; Houck et al., 1998).
O. Predators. Bruce (1972a) reported that a spring salamander ate a member of the P. jordani complex (either a red-legged salamander [P. shermani] or a southern gray-cheeked salamander). Other predators likely include woodland mammals, birds, and snakes.
P. Anti-Predator Mechanisms. Nocturnal. Secretive. All members of the genus Plethodon produce noxious skin secretions (Brodie, 1977). Members of the Plethodon jordani complex frequently become immobile when contacted initially. Southern gray-cheeked salamanders were included in a field study on immobility, however it is not possible to separate their behavior from the other members of this complex in this published data set. Immobility may increase survival by making the salamander less likely to be detected, especially by visually oriented predators (Dodd, 1989).
Q. Diseases. Unknown.
R. Parasites. Rankin (1937) lists parasites from at least two species of the Plethodon jordani complex. It is not possible to determine which parasites were found in which salamander species, but it is likely that some of these salamanders were southern gray-cheeked salamanders. The following parasites are noted: Crytobia borrelis, Eutrichomastix batrachorum, Hexamitus intestinalis, Karotomorpha swezi, Prowasekella longifilis, Tritrichomonas augusta, Brachycoelium hospitale and Crepidobothrium cryptobranchi.
4. Conservation. Among members of the P. jordani complex, southern gray-cheeked salamanders have one of the widest distributions, and they are not protected by any state within their range. While relatively wide ranging, southern gray-cheeked salamanders usually are restricted to higher elevations. Suitable habitat at these elevations may be separated by stretches of lower uninhabited areas, and populations are often disjunct. Within their range there are many federal and state properties that contain suitable habitat for these salamanders.
Southern gray-cheeked salamanders are relatively resilient to disturbances, such as those associated with timbering operations, and frequently are found in second-growth forests and relatively small, fragmented woodlots (D.A.B., personal observation). However, clearcuts negatively affect populations (Petranka et al., 1993, 1994; Ash et al., 2003) and southern gray-cheeked salamanders disappeared from clearcut areas in Macon County, North Carolina, within four years of lumbering (Ash, 1988, 1997).
As with all species of Plethodon, southern gray-cheeked slimy salamanders do not migrate to breeding grounds and do not have large home ranges. Thus, they can exist in habitats of smaller size than many other amphibian species. Conservation activities that promote mature closed-canopy forests should benefit this species.
Acknowledgments. Thanks to Richard Highton, who reviewed this account and gave us the benefit of his insight and experience.
1David A. Beamer
2Michael J. Lannoo
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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