© 2009 Stephen Bennett (1 of 5)
Country distribution from AmphibiaWeb's database: United States
Plethodon websteri Highton, 1979
David A. Beamer1
1. Historical versus Current Distribution. The distribution of Webster's salamanders (Plethodon websteri) is unusual. These animals occur in a relatively small number of scattered sites from eastern Louisiana, through Mississippi, Alabama, and Georgia, to western South Carolina. Historical data are lacking.
2. Historical versus Current Abundance. Generally unknown. Highton (2003) sampled two sites in Etowah County, Alabama, from 1971–'88, and one site in Winston County, Mississippi, from 1976–'84, then re-sampled these sites during the 1990s and found fewer animals at each site. Whether these data represent true declines or natural population fluctuations will only be determined by subsequent monitoring.
3. Life History Features.
A. Breeding. Reproduction is terrestrial. Males show maximum spermatogenic activity during the late summer. The vasa deferentia were packed with sperm from January–March, and the mental gland was most swollen at this time, indicating that courtship and insemination probably occur during this period (Semlitsch and West, 1983).
i. Breeding migrations. Undocumented, but breeding migrations are not known for any Plethodon species.
ii. Breeding habitat. Unknown.
B. Eggs. In South Carolina, females likely lay their eggs from June–September. Despite intensive searching, gravid females could not be found later than June (Semlitsch and West, 1983).
i. Egg deposition sites. Unknown, but likely to be in underground cavities.
ii. Clutch size. Mean number of ovarian follicles is 5.8 (69 females), with a range of 3–8 (Semlitsch and West, 1983). The number of follicles increases with female length. Follicle diameter is 3 mm.
C. Direct Development. Hatching probably takes place in October–November, as emerging juveniles with remnants of yolk have been found at this time. The smallest Webster’s salamanders were found in November and were 12.5 mm SVL (Semlitsch and West, 1983).
i. Brood sites. Females likely oviposit and brood underground from June–September (Semlitsch and West, 1983).
ii. Parental care. Unknown, but it is likely that females brood, as with other species of Plethodon.
D. Juvenile Habitat. Juveniles with yolk remnants begin to emerge onto the forest floor in October. Growth is about 1.3 mm/mo for the smallest animals, 1.1 mm/mo for second-year animals, and 0.33 mm/mo for adults.
E. Adult Habitat. Adult Webster’s salamanders are found in mixed mesophytic forest bordering rocky, lower-order streams (Semlitsch and West, 1983). Semlitsch and West (1983) point out that at their study sites, predominant canopy species include sugar maples (Acer saccharinum), pignut hickory (Carya glabra), red oak (Quercus rubra), yellow poplar (Liriodendron tulipifera), sweetgum (Liquidambar styraciflua), and slippery elm (Ulmus rubra). The vegetation is considered to be a relict mesophytic community and contains disjunct populations of plant species.
On 4 February 1967, Webster’s salamanders were collected in Clarke County, Alabama, under rocks and logs along the base of the slopes of an extensive ravine characterized by limestone outcroppings. Conspicuous floral elements at this site include blue beech, long-leaf magnolia, and sweet gum (Blaney and Relyea, 1967).
Webster’s salamanders were collected from Winston County, Mississippi, in March–April 1958 under decaying logs near a small stream and in a pasture in a second-growth forest. The major tree species present were sweetgum, black willow, red and white oak, yellow popular, American elm, shagbark and mockernut hickory, beech, and red maple (Ferguson and Rhodes, 1958).
F. Home Range Size. Unknown, but as with other Plethodon species is likely to be small.
G. Territories. At least some members of the Plethodon dorsalis complex aggressively defend territories (Thurow, 1976), it is unknown whether Webster’s salamanders establish and defend territories.
H. Aestivation/Avoiding Dessication. Webster's salamanders appear to remain underground during the summer. Forest floor activity was restricted to times when air temperatures were between 15–30 ˚C. Salamanders were not found in the summer even after heavy rainfall that left the leaf litter wet (Semlitsch and West, 1983).
I. Seasonal Migrations. Vertical migrations occur seasonally; Semlitsch and West (1983) report Webster’s salamanders as being active from October–May and apparently retreating underground during the summer.
J. Torpor (Hibernation). Animals are active throughout the winter and are commonly found near the surface at this time (Semlitsch and West, 1983).
K. Interspecific Associations/Exclusions. Salamanders associated with Webster's salamanders at Semlitsch and West's (1983) study site include Atlantic Coast slimy salamanders (Plethodon chlorobryonis), eastern newts (Notophthalmus viridescens), southern dusky salamanders (Desmognathus auriculatus), southern two-lined salamanders (Eurycea cirrigera), and long-tailed salamanders (E. longicauda).
In Clarke County, Alabama, the following species were collected with Webster’s salamanders: Mississippi slimy salamanders (P. mississippi), spotted dusky salamanders (Desmognathus conanti; may actually have been D. auriculatus), and southern two-lined salamanders (Eurycea cirrigera; Blaney and Relyea, 1967).
Webster’s salamanders contact southern zigzag salamanders (P. ventralis) in Jefferson County, Alabama. The contact zone may be little more than 1 km wide in this area. There is no evidence of hybridization between these two species. There is evidence of character displacement, as both species generally exhibit polymorphism for striped and unstriped morphs, but in this area Webster’s salamanders are all of the striped morph and southern zigzag salamanders are all of the unstriped morph (Highton, 1976, 1985).
The following salamanders were collected along with Webster’s salamanders on Mount Cheaha, Cleburne County, Alabama: spotted dusky salamanders (Desmognathus conanti), seepage salamanders (D. aeneus), seal salamanders (D. monticola), southern two-lined salamanders (Eurycea cirrigera), three-lined salamanders (E. guttolineata), spring salamanders (Gyrinophilus porphyriticus), red salamanders (Pseudotriton ruber), and northern slimy salamanders (P. glutinosus; Rubenstein, 1969).
L. Age/Size at Reproductive Maturity. The estimated age at sexual maturity for both males and females is between 21–26 mo. The estimated age when Webster’s salamanders first court is between 29 and 31 mo, and the age of first oviposition is from 34–37 mo. Both sexes breed annually.
The smallest mature male in a McCormick County, South Carolina, study was 29 mm SVL and the smallest mature female was 27.5 mm (Semlitsch and West, 1983).
M. Longevity. Unknown.
N. Feeding Behavior. The following food items were found in specimens collected during March–April from Upson County, Georgia, and Lee County, Alabama: Gastropoda, Annelida, Acarina, Araneae, Pseudoscorpionida, Chilopoda, Isopoda, Collembola, Isoptera, Diptera, Lepidoptera, Thysanoptura, Coleoptera, ants, wasps, and unidentified larvae. Larger individuals generally feed on larger prey (ants and termites); smaller individuals feed on smaller prey (springtails and mites; Camp and Bozeman, 1981).
Webster's salamanders in South Carolina have a long (8 mo) continuous activity period, during which they forage and obtain resources (Semlitsch and West, 1983).
O. Predators. Undocumented, but likely include forest snakes, birds, and small mammals.
P. Anti-Predator Mechanisms. Nocturnal. Secretive. All members of the genus Plethodon produce noxious skin secretions (Brodie, 1977). Webster's salamanders frequently become immobile when initially contacted. 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. Unknown.
4. Conservation. Webster's salamanders are listed as an Endangered species in South Carolina and as a Species of Special Concern in Louisiana. This species occurs in several isolates. Within some of these isolates there are not any federal and state properties that contain suitable habitat for these salamanders.
As with all species of Plethodon, Webster's salamanders do not migrate to breeding grounds and they 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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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 13 Apr 2021.
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