Southeastern Slimy Salamander
© 2016 Dr. Joachim Nerz (1 of 9)
Country distribution from AmphibiaWeb's database: United States
Plethodon grobmani Allen and Neill, 1949
David A. Beamer1
1. Historical versus Current Distribution. Southeastern slimy salamanders (Plethodon grobmani) are distributed from southern Alabama and southern Georgia south to central Florida (Allen and Neill, 1949; Highton, 1989). There is no evidence to suggest that their current distribution differs from their historical distribution, but it seems likely that populations have been lost due to habitat loss and alteration (Lazell, 1994).
2. Historical versus Current Abundance. Four of five populations sampled by Highton (2003) prior to 1987 and re-sampled in 1990 or later appear to have declined, although numbers of animals observed were high in Jackson County, Florida, and Schley County, Georgia. Additional sampling will be required to determine whether trends in these data reflect true declines or natural population fluctuations.
3. Life History Features.
A. Breeding. Reproduction is terrestrial. Spermatogenesis occurs from October–December in Florida. The vasa deferentia are filled with sperm until the mid-summer breeding season. Courtship activity and insemination probably occur from mid July to mid August, several weeks before the females lay their eggs.
i. Breeding migrations. Undocumented, but breeding migrations are not known for any Plethodon species.
ii. Breeding habitat. Unknown.
i. Egg deposition sites. Southeastern slimy salamanders in Florida deposit their eggs in or under rotting logs (Highton, 1956, 1962b).
ii. Clutch size. Clutches discovered in the field in Florida contained from 5–11 eggs. Gravid females from Florida contained from 10–22 heavily yolked ovarian eggs (Highton, 1956, 1962b).
C. Direct Development. Embryonic gills are lost 2–3 d after hatching. The incubation period is about 2 mo, with hatching taking place in October–November. Hatchlings range in size from 12–14 mm SVL (20–22 mm TL; Highton, 1956).
i. Brood sites. Females brood their clutches in or under rotting logs (Highton, 1956).
ii. Parental care. The six known clutches of eggs were each accompanied by a female. However, recently spent females have been found without eggs; it is unknown if these females abandoned their eggs or if they were lost to predators (Highton, 1956, 1962b).
D. Juvenile Habitat. Similar to adults. Juveniles likely stay at the nest site for the first 2 mo after hatching. They are first found on the surface in late December (Highton, 1956).
E. Adult Habitat. Southeastern slimy salamanders are common in steephead ravines, maritime forests, and river bottom hardwood forests (Lazell, 1994; Enge, 1998). Much of the area within the range of southeastern slimy salamanders historically was covered with savanna and prairie, and in these areas they are rare or absent. Southeastern slimy salamanders do not require pristine habitats or old-growth forests and are often found under discarded rubbish. There may be a minimum size wood lot necessary as they are absent from small wood lots (Lazell, 1994). A southeastern slimy salamander was found in a cave in Alachua County, Florida (Peck, 1974).
F. Home Range Size. Individuals are sedentary, rarely moving > 60 cm from their original capture and release sites (Highton, 1956).
G. Territories. At least some members of the Plethodon glutinosus complex aggressively defend territories (Thurow, 1976); it is unknown whether southeastern slimy salamanders do the same.
H. Aestivation/Avoiding Dessication. Southeastern slimy salamanders in all size groups were rarely encountered during the summer in peninsular Florida, this is despite the fact that there is increased rainfall at this time. Higher temperatures and higher evaporation rates may be factors inhibiting summer activity. During the summer, the growth rate of the young decreases (Highton, 1956).
I. Seasonal Migrations. Southeastern slimy salamanders probably move vertically from forest floor sites to underground sites in response to seasonal dry and cold conditions. Southeastern slimy salamanders were much more abundant beneath logs in steephead ravines in the Florida Panhandle during the winter and early spring than during the summer (D.A.B., personal observations).
J. Torpor (Hibernation). Generally unknown, but southeastern slimy salamanders likely avoid cold conditions by seeking shelter in underground sites.
K. Interspecific Associations/Exclusions. Allen and Neill (1949) discuss hybrids with other members of the P. glutinosus complex.
During a drift-fence survey of steephead ravines in the Apalachicola and Ochlockonee River drainages, southeastern slimy salamanders were captured with one-toed amphiumas (Amphiuma pholeter), Apalachicola dusky salamanders (Desmognathus apalachicolae), southern two-lined salamanders (Eurycea cirrigera), three-lined salamanders (E. guttolineata), four-toed salamanders (Hemidactylium scutatum), eastern newts (Notophthalmus viridescens), mud salamanders (Pseudotriton montanus), and red salamanders (P. ruber; Enge, 1998).
Historically, southeastern slimy salamanders were found with southern dusky salamanders (Desmognathus auriculatus) at Devil’s Millhopper State Geological Site, Alachua County, Florida (Dodd, 1998). However, most known populations of southern dusky salamanders within the range of southeastern slimy salamanders are now extirpated (Means, 2001b).
In Alabama, southeastern slimy salamanders have been observed in the burrows of Red Hills salamanders (Phaeognathus hubrichti) along with the following salamanders: southern two-lined salamanders, three-lined salamanders, and eastern newts (Brandon, 1966b; Dodd, this volume). Seal salamanders (Desmognathus monticola) are common at some Alabama sites with southeastern slimy salamanders (Brandon, 1965b).
L. Age/Size at Reproductive Maturity. The holotype is an adult female, 49.9 mm SVL. Allen and Neill (1949) mention a series of their 20 largest specimens, which average 53.7 mm. The smallest mature female from Florida was 45 mm, the smallest mature male was 37 mm (Highton, 1956).
Maturity in female southeastern slimy salamanders is more closely related to age than size. Females do not mature until they are 2 yr old and cannot lay eggs until they approach the age of 3. Female southeastern slimy salamanders have an annual breeding cycle (Highton, 1956, 1962b).
Male southeastern slimy salamanders generally mature when they are 2 yr old, though some large individuals may mature when they are 1 yr old and breed at age 2. Many maturing 1-yr-old males do not produce functional spermatozoa, but instead undergo an abortive sexual cycle in which the maturing sex cells degenerate. These males do not breed until the age 3. Male southeastern slimy salamanders breed annually (Highton, 1956, 1962b).
M. Longevity. Unknown.
N. Feeding Behavior. The stomach contents of thirteen southeastern slimy salamanders from Alabama contained snails, millipedes, spiders, phalangids, beetles, Hymenoptera (mainly ants), and miscellaneous insect larvae (Brandon, 1965b).
O. Predators. Undocumented, but likely to include forest snakes, birds, and small mammals.
P. Anti-Predator Mechanisms. Members of the Plethodon glutinosus complex produce large amounts of skin secretions that have an adhesive component (Brodie et al., 1979). Individuals will vocalize when physically disturbed (Highton, 1956).
Q. Diseases. Unknown.
R. Parasites. Unknown.
4. Conservation. Southeastern slimy salamanders are not protected in any of the states within their range. Among members of the P. glutinosus complex, southeastern slimy salamanders have one of the widest distributions. Within this range there are several federal and state properties that contain suitable habitat for these salamanders.
Southeastern slimy salamanders are relatively resilient to disturbances, such as those associated with timbering operations, and are frequently found in second-growth forests and relatively small, fragmented woodlots (Lazell, 1994; D.A.B., personal observation).
As with all species of Plethodon, southeastern slimy salamanders do not migrate or have large home ranges. Thus, they can exist in habitats of smaller size than many other amphibian species. However, there may be a minimum size habitat necessary, as they are absent from small wood lots (Lazell, 1994). 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. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Jul 2018.
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