Red Hills Salamander
© 1997 Matthew J. Aresco (1 of 12)
Phaeognathus hubrichti Highton, 1961
C. Kenneth Dodd Jr.1
1. Historical versus Current Distribution. Red Hills salamanders (Phaeognathus hubrichti) are known from 13 discrete populations located in the Red Hills physiographic region between the Alabama and Conecuh rivers in south-central Alabama (Dodd, 1991). Electrophoretic evidence suggests weak separation of populations east and west of the Sepulga River (McKnight et al., 1991). Whereas salamanders have disappeared or declined at several sites within these populations because of adverse land-use practices, there is no evidence that the current range of Red Hills salamanders is any different from its historical range.
2. Historical versus Current Abundance. Because of the secretive nature of this species, there are no range-wide estimates of abundance, either current or historical. Areas occupied by Red Hills salamanders may be widely separated, and even within a site, burrows are not spaced uniformly. Presumably, burrow density and abundance are correlated with Red Hills salamander density and abundance, but the relationship is unclear. Dodd (1991) used time constraint sampling to determine the location of sites with relatively large numbers of burrows, then used line transect techniques to obtain statistically rigorous estimates of burrow abundance (Dodd, 1990b). In optimum habitat (n = 10 sites), he estimated 2.6–9.4 burrows/100m2 (mean = 5.05 burrows/100m2). Carroll et al. (2000) used mark-recapture data collected from a single 18-m transect to estimate a salamander abundance of 0.5 animals/m2, again in optimal habitat. They estimated that 26 animals inhabited the 33 burrows observed, or 0.8 salamanders/burrow. Burrow abundance varies considerably among sites, however, particularly in areas affected by clearcutting and other forestry practices. In addition, there are no long-term data on the number of burrows occupied by an individual salamander; salamanders have been observed in > 1 burrow, and > 1 salamander has been observed in a single burrow. Finally, burrows do not seem to persist. Gunzburger and Guyer (1998) found that 50% of marked burrows remained open after 6 mo and inferred that Red Hills salamanders must continually repair old burrows and open new burrows because of the dynamic nature of the steep ravines they inhabit. These factors taken together suggest that local abundance varies considerably and that it will be difficult to obtain good estimates of relative abundance.
Although the factors discussed above make it difficult to obtain accurate estimates of Red Hills salamander abundance, it is apparent that clearcutting and other forestry practices reduce or eliminate Red Hills salamanders in what was once optimal habitat. Red Hills salamander burrows may persist at reduced densities after cutting as long as burrow systems are not destroyed. It is unknown how long it might take for densities to reach pre-cut levels. If burrow systems are destroyed mechanically, as by plowing, tilling, or other forms of intensive site preparation, Red Hills salamanders disappear or are confined to small refugia unimpacted by site disturbance. Thus, current Red Hills salamander abundance is probably similar to historical abundance at some sites, but drastically reduced at other sites depending on the historical and current land-use practices.
3. Life History Features. The life history and biology of Red Hills salamanders are summarized by Petranka (1998).
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. It is unknown how Red Hills salamanders find each other, but true breeding migrations probably do not occur.
ii. Breeding habitat. Courtship by Red Hills salamanders presumably takes place within the burrow system or in deep interconnecting rock fissures underground.
i. Egg deposition sites. Egg clusters of this species have not been found in nature, but egg deposition presumably takes place within the burrow system or in deep interconnecting rock fissures underground.
ii. Clutch size. In captivity, a single 115-mm Red Hills salamander produced 16 eggs (Brandon and Maruska, 1982).
C. Direct Development. Red Hills salamanders have direct development within the egg, one of only three desmognathines with this form of development. When hatched, the young resemble the adults.
i. Brood Sites. Eggs are presumably deposited within the burrow system or in deep interconnecting rock fissures underground. In captivity, a single 115-mm Red Hills salamander attached her egg cluster to an overhanging support via a stalk (Brandon and Maruska, 1982).
ii. Parental Care. Parental care is unknown, although many desmognathine salamanders remain with their eggs during development. In the single case of egg deposition in captivity, the female did not brood her eggs and none developed (Brandon and Maruska, 1982).
D. Juvenile Habitat. Very few juveniles have been observed, and all within the burrows of adult salamanders. Nothing is known concerning specialized habitat characteristics.
E. Adult Habitat. Males and females occupy similar habitats and are active year-round (Bakkegard, 2001, 2002). Burrows are key to the survival of Red Hills salamanders, and few individuals have been observed outside burrows (Gunzburger and Guyer, 1998). Red Hills salamander burrows are confined to steep (slope: mean = 50˚; height: mean = 17 m) mesic ravines within the Tallahatta and Hatchetigbee geological formations. The Tallahatta and Hatchetigbee geological formations consist of extremely porous rocks with a large water-holding capacity. Such ravines are humid and have friable soils ideal for burrow construction and large invertebrate populations. North-facing slopes are preferred, but salamanders may be found on slopes facing all directions. Most burrows are found on the lower 2/3 of a slope. The forest canopy consists of broad-leaved deciduous trees that provide shade and retain high humidity. These conditions combine to provide optimal habitat (see Valentine, 1963b; Schwaner and Mount, 1970; Jordan, 1975; French and Mount, 1978; and Dodd, 1991).
F. Home Range Size. Unknown.
G. Territories. Red Hills salamanders rarely leave their burrows, although movements away from the burrow have been observed (Bakkegard, 2001, 2002). It is unknown if Red Hills salamanders defend burrows, but sightings of different Red Hills salamanders within a single burrow suggest this is not the case. Males could defend territories (burrows?) during the breeding season, but it is not known if they do so.
H. Aestivation/Avoiding Dessication. Red Hills salamanders probably retreat deep into the burrow system during periods of extreme cold or drought. However, they likely are active year-round when temperature and moisture conditions are favorable. The periods of greatest activity are the spring and summer seasons.
I. Seasonal Migrations. Not known to occur.
J. Torpor (Hibernation). See "Aestivation/Avoiding Dessication" above.
K. Interspecific Associations/Exclusions. The burrows of the Red Hills salamanders are used by other salamanders, including southern two-lined salamanders (Eurycea cirrigera), three-lined salamanders (E. guttolineata), southeastern slimy salamanders (Plethodon grobmani), and eastern newts (Notophthalmus viridescens; see also Brandon, 1966b). Invertebrates also undoubtedly use the burrows.
L. Age/Size at Reproductive Maturity. Brandon (1965b) suggested that Red Hills salamander males attain sexual maturity at approximately 80 mm “body length” (presumably snout-vent length) and females at 100 mm body length. For females, this occurs at 5–6 yr of age (Parham et al., 1996). The age of maturity for males is uncertain, but males probably mature earlier than females. Egg deposition extends from early spring to September (Brandon, 1965; Schwaner and Mount, 1970).
M. Longevity. Based on skeletochronology, Parham et al. (1996) recorded a 121-mm SVL male at 11 yr. They suggested that it is unlikely that Red Hills salamanders live much longer.
N. Feeding Behavior. Red Hills salamanders sit at or just inside the burrow mouth and ambush invertebrates passing the entrance or entering the burrow. At night, they partially emerge from the burrow to attack prey. Prey include snails, millipedes, insects, insect larvae, spiders, mites, and probably any small animal that can be caught and swallowed (Brandon, 1965b; Gunzburger, 1999). They appear to avoid daddy longlegs (Phalangiidae; Bakkegard, 2002).
O. Predators. Direct predation has not been recorded, but small mammals (shrews; Soricidae) and reptiles likely eat this species. Feral pigs (Sus sp.) and armadillos (Dasypus novemcinctus) are common in the Red Hills and do considerable damage to the steep ravines inhabited by Red Hills salamanders. They undoubtedly dig out and eat salamanders whenever possible (Dodd, 1991).
P. Anti-Predator Mechanisms. The burrow would seem to be their primary defense. Red Hills salamanders are not known to possess granular skin glands, and hence apparently do not have skin secretions that repel predators. No defensive postures are known. However, Red Hills salamanders are capable of biting and will spin when grabbed (C.K.D. and C. Guyer, personal communication).
Q. Diseases. Nothing known.
R. Parasites. Intestinal trematodes (Brachycoelium salamandrae) and colic roundworms (Oxyuris sp.; Brandon, 1965b).
4. Conservation. Red Hills salamanders are protected as Threatened under provisions of the Federal Endangered Species Act of 1973, as amended (U.S.F.W.S., 1976). Six Habitat Conservation Plans (HCPs) for populations of Red Hills salamanders, covering approximately 25,169 ha, have been approved by the U.S. Fish and Wildlife Service in cooperation with timber companies in south Alabama. The goals of the Red Hills salamander HCPs are to allow for timber harvesting while promoting species conservation. Red Hills salamanders are listed as a protected non-game species by the State of Alabama.
Virtually all Red Hills salamander habitat is on private land, with only a small amount owned by the U.S. Army Corps of Engineers and the State of Alabama. Several (n = 25) excellent tracts of habitat remained in private ownership in 1988, and these were recommended for acquisition for conservation purposes (Dodd, 1988). To date, none have been acquired. Long-term protection is best assured through private landowner cooperation. With that in mind, Dodd (1988, 1991) recommended a series of management actions that would help to maintain the integrity of salamander habitat, especially in areas where forestry occurred. These included avoiding clearcutting on slopes containing salamander burrows; eliminating mechanical site preparation; maintaining woody leaf litter and an overstory hardwood tree canopy; leaving buffer zones above and below slopes containing salamander burrows; avoiding herbicides and other chemical applications; and allowing hardwoods to regenerate on previously cut and selectively cut slopes containing salamander burrows. Protection from collecting is also important for this species because of its restricted range and vulnerable populations; because it is the sole member of a monotypic genus, the collector value is high.
In areas unaffected by forestry (which are few in south Alabama), populations of Red Hills salamanders are likely stable. If habitat is degraded, Red Hills salamander populations will decline and may disappear. For this reason, periodic assessments of Red Hills salamander habitat must be carried out, especially to ensure that HCP provisions are being honored and that salamander habitat is protected during forestry operations.
1C. Kenneth Dodd Jr.
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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