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Plethodon yonahlossee Dunn, 1917(a)
David A. Beamer1
1. Historical versus Current Distribution. Yonahlossee salamanders (Plethodon yonahlossee) are found in the Blue Ridge Mountains of western North Carolina, northeastern Tennessee, and southwestern Virginia (Dunn, 1917a; Bishop, 1943; Hairston, 1949; Newman, 1954b; Petranka, 1998). They occur between about 437–1,737 m in elevation (Petranka, 1998).
Highton (2003) sampled four populations during or prior to 1987, and again in 1993 or later, and could not find animals at three sites (two along the North Carolina–Tennessee border and one in Grayson-Wythe County, Virginia). Additional sampling is required to determine whether these data reflect true declines (perhaps extirpations) or natural population fluctuations.
2. Historical versus Current Abundance. Unknown, but threats include aggressive forestry practices (Petranka et al., 1993, 1994; Petranka, 1998; but see Ash, 1988, 1997, and Ash and Bruce, 1994).
Gordon et al. (1962) compared their collection to a collection made by Dunn 44 yr earlier. The collections were made in the same area, though there had been at least one lumbering of the area between the collections. The number of Yonahlossee salamanders was nearly identical in the two collections.
3. Life History Features.
A. Breeding. Reproduction is terrestrial. Spermatogenesis likely occurs after emergence from hibernation. A spermatogenic wave in the anterior third of the testes was found in a specimen collected on 25 May. Courtship probably occurs in early August, as at this time pairs of salamanders have been found under a single small cover object and males have conspicuous mental glands (Pope, 1950).
i. Breeding migrations. Undocumented, but breeding migrations are not known for any Plethodon species.
ii. Breeding habitat. Unknown.
B. Eggs. Females probably begin to lay their eggs in late August. Advanced ova were found in three females collected between 11–16 August at Whitetop Mountain and Comer’s Rock, Virginia (Pope, 1950).
i. Egg deposition sites. Unknown, but likely to be in underground cavities.
ii. Clutch size. Three females (77–78 mm SVL) collected between 11–16 August at Whitetop Mountain and Comer’s Rock, Virginia, had 19, 24, and 27 mature ova (Pope, 1950).
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. Juveniles have been collected in the same areas as adults (Pope, 1950; D.A.B., personal observations). Both juveniles and adults emerge from burrows at night to forage. Juveniles are most active for about 1 hr after sunset, while adult activity peaks 1 or 2 hr later (Gordon et al., 1962).
E. Adult Habitat. Yonahlossee salamanders have been recorded from both virgin and second-growth forest (Dunn, 1917a; Gordon et al., 1962). Bailey (1937) reports finding Yonahlossee salamanders common in a rock-filled ravine near Swannanoa, Buncombe County, North Carolina.
In the Iron Mountains, Johnson County, Tennessee, Yonahlossee salamanders have been found in a variety of habitats. Here they have been collected on bare, rock-covered road embankments exposed to the sun, in a talus slope, in deciduous forest, near a wet weather spring, and in an open pasture (Pope, 1950).
In Rutherford County, North Carolina, Yonahlossee salamanders are commonly found in deep crevices of metamorphic rock (Adler and Dennis, 1962; Rubin, 1969). Rock crevices are also occasionally occupied in Avery County and Watuga County, North Carolina (Adler and Dennis, 1962; Guttman et al., 1978).
Dunn (1926) reports that they create long burrows in the forest floor, with openings usually under a fallen log or piece of bark (Bishop, 1943; Martof et al., 1980). However, Pope (1950) suggests that Yonahlossee salamanders do not excavate burrows but may reopen partly obliterated passages.
Petranka (1998) challenged Hairston's (1949) claims that Yonahlossee salamanders in the Black Mountains of North Carolina are generally found within 30 m of streams and are most common in old growth forests.
Yonahlossee salamanders are often found in and under rotting logs, under bark on the ground or still on its log, and under stones. Preferred niches are old windfalls that have shed most of their bark and logs > 25 cm (10 in) in diameter, with not more than 5–15 cm (1–3 in) of the log below the surface and a thick layer of leaf accumulation at the log–ground interface (Dunn, 1926; Pope, 1950; Gordon et al., 1962).
F. Home Range Size. Unknown, but small home ranges are typical for Plethodon species.
G. Territories. Both juveniles and adults aggressively defend territories in laboratory terraria (Thurow, 1976).
H. Aestivation/Avoiding Dessication. Yonahlossee salamanders are well represented in collections made during the summer (Dunn, 1917a, 1920; Bailey, 1937; Pope, 1950; Adler and Dennis, 1962; Rubin, 1969; Guttman et al., 1978).
I. Seasonal Migrations. Animals likely move vertically from forest-floor sites to underground sites in response to seasonal dry and cold conditions.
J. Torpor (Hibernation). Unknown, but it is likely that Yonahlossee salamanders seek underground retreats during winter weather.
K. Interspecific Associations/Exclusions. In Avery County, North Carolina, Yonahlossee salamanders were found with eastern newts (Notophthalmus viridescens), Blue Ridge dusky salamanders (Desmognathus orestes), seal salamanders (D. monticola), red-backed salamanders (Plethodon cinereus), northern gray-cheeked salamanders (P. montanus), white-spotted slimy salamanders (P. cylindraceus), and Blue Ridge two-lined salamanders (Eurycea wilderae; Gordon et al., 1962).
Pope (1950) reports a Yonahlossee salamander taken on Grandfather Mountain, North Carolina, at an elevation of 1,737 m (5,700 ft). Weller’s salamanders (P. welleri), northern gray-cheeked salamanders, pygmy salamanders (D. wrighti), and Blue Ridge mountain dusky salamanders are well known from this elevation at Grandfather Mountain.
Hairston (1949) reports the following salamanders along with Yonahlossee salamanders from the Black Mountains area, Yancey County, North Carolina: spring salamanders (Gyrinophilus porphyriticus), red salamanders (Pseudotriton ruber), Blue Ridge two-lined salamanders (Eurycea wilderae), black-bellied salamanders (Desmognathus quadramaculatus), seal salamanders, Carolina mountain dusky salamanders (D. carolinensis), pygmy salamanders (D. wrighti), shovel-nosed salamanders (D. marmoratus), white-spotted slimy salamanders, and northern gray-cheeked salamanders.
At Limestone Cove, Unicoi County, Tennessee, Yonahlossee salamanders have been found with Weller’s salamanders, white-spotted slimy salamanders, eastern newts, seal salamanders, Carolina mountain dusky salamanders, and black-bellied salamanders (Thurow, 1963).
The following species were found on a cliff face with Yonahlossee salamanders in Rutherford County, North Carolina: green salamanders (Aneides aeneus), Blue Ridge gray-cheeked salamanders (P. amplus), white-spotted slimy salamanders, and Ocoee salamanders (Desmognathus ocoee; Adler and Dennis, 1962; Rubin, 1969).
At Whitetop Mountain, Virginia, Yonahlossee salamanders have been found with Wehrle’s salamanders (P. wehrlei; Highton, 1962a). Pope (1950) reports Yonahlossee salamanders from elevations between 1,151–1,669 m (3,775–5,475 ft) on Whitetop Mountain. Organ (1961a) reports the following species from this same area: red-backed salamanders, white-spotted slimy salamanders, northern gray-cheeked salamanders, Weller’s salamanders, southern ravine salamanders (P. richmondi), red salamanders (Pseudotriton ruber), spring salamanders (Gyrinophilus porphyriticus), Blue Ridge two-lined salamanders, black-bellied salamanders (Desmognathus quadramaculatus), seal salamanders, northern dusky salamanders (D. fuscus), Blue Ridge mountain dusky salamanders, and shovel-nosed salamanders.
Yonahlossee salamanders are sympatric with white-spotted slimy salamanders at intermediate elevations throughout much of the Blue Ridge Province east of the French Broad River. There is no evidence of hybridization between these species (Highton and Peabody, 2000).
Yonahlossee salamanders are sympatric with northern slimy salamanders (P. glutinosus) only in the vicinity of Skulls Gap, Smyth County, Virginia. A probable F1 hybrid was found at this location (Highton and Peabody, 2000).
Yonahlossee salamanders are widely sympatric throughout the range of Blue Ridge gray-cheeked salamanders (P. amplus). There is no evidence of hybridization between these species (Highton and Peabody, 2000).
Yonahlossee salamanders are widely sympatric with northern gray-cheeked salamanders (P. montanus) at the eastern edge of the Blue Ridge isolate. There is no evidence of hybridization (Highton and Peabody, 2000).
Yonahlossee salamanders tend to be much more altitudinally restricted than any of these associated species. A comparison between Yonahlossee salamanders and white-spotted slimy salamanders suggests a large degree of dietary overlap, although there is no evidence to suggest that competitive exclusion occurs (Pope, 1950).
L. Age/Size at Reproductive Maturity. Cloacal gland papillae and mental glands are evident in males at approximately 56 mm SVL. It is likely that these salamanders are mature. A 60-mm female appeared to be mature, though a 66-mm female was immature. Maturity in females is likely reached somewhere around 60–66 mm SVL. Sexual maturity in Yonahlossee salamanders probably occurs when they are almost 3 yr old (Pope, 1950).
A cliff-dwelling population of Yonahlossee salamanders from Rutherford County, North Carolina, apparently does not mature until a large size. Males do not mature until they are > 65 mm and females do not mature until they are > 61 mm (Adler and Dennis, 1962).
M. Longevity. Unknown.
N. Feeding Behavior. Juveniles forage most actively about 1 hr after sunset, while adult foraging activity peaks 1 or 2 hr later (Gordon et al., 1962).
An examination of the stomachs of 28 Yonahlossee salamanders during summer from Rutherford County, North Carolina, included representatives from the following invertebrate taxa: Gastropoda, Araneida, Diplopoda, Gastropoda, Curculionidae, coleopteran adults and larvae, lepidopteran larvae, Collembola, Orthoptera, dipteran adults, larvae, and pupae, shed skins, Acarina, Hymenoptera, Coleoptera, Lepidoptera, Hemiptera, Chilopoda, Pseudoscorpianida, Staphylinidae, Annelida, Mecoptera, Neuroptera, and Nematoda (Rubin, 1969).
Food items from 50 Yonahlossee salamanders collected in the Iron Mountains included Collembola, Isoptera, lepidopteran larvae, dipteran larvae, coleopteran adults and larvae, Chelonethida, Araneida, Acarina, Diplopoda, Chilopoda, Isopoda, and Pulmonata. These specimens were kept alive for 1–3 d after capture, so it is possible soft-bodied prey that are digested more rapidly were absent. A female (77 mm SVL) from this series had eaten 15 invertebrates (Pope, 1950).
Rankin (1937) reported centipedes, ants, and beetles from the stomachs of three specimens. In captivity, a Yonahlossee salamander ate a small member of Plethodon jordani complex (Thurow, 1976).
O. Predators. Undocumented, but likely to include forest snakes, birds, and small mammals.
P. Anti-Predator Mechanisms. Yonahlossee salamanders produce tail secretions that are noxious to birds and other potential predators (Petranka, 1998). Yonahlossee 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. Rankin (1937) reported the following parasites from Yonahlossee salamanders: Protozoa—Cytamoeba bacterifera, Eutrichomastix batrachorum, Karotomorpha swezi, Prowazekella longifilis, and Tritrichomonas augusta; Trematoda—Brachycoelium hospitale; Nematoda—Oxyuris magnavulvaris.
Yonahlossee salamanders from a cliff-face population in Rutherford County, North Carolina, were infected with dermal mites (Hannemania hegeneri; Adler and Dennis, 1962).
4. Conservation. Yonahlossee salamanders are not protected in any of the states within their range. While relatively wide ranging, Yonahlossee salamanders are usually found from intermediate to high elevations. Suitable habitat at these elevations may be separated by stretches of lower uninhabited areas, and populations are often separated. Within this range, there are many federal and state properties that contain suitable habitat for these salamanders.
Yonahlossee 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 (Gordon et al., 1962; D.A.B., personal observations). However, aggressive forestry practices may negatively affect populations (Petranka et al., 1993, 1994; Petranka, 1998).
As with all species of Plethodon, Yonahlossee 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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