Inyo Mountains Salamander
© 2006 William Flaxington (1 of 14)
Batrachoseps campi Marlow, Brode and Wake, 1979
Robert W. Hansen1
1. Historical versus Current Distribution. Inyo Mountains salamanders (Batrachoseps campi) were discovered in 1973 from two desert springs (French Spring and Long John Canyon) on the western slopes of the Inyo Mountains in California's northern Mojave Desert (Marlow et al., 1979). Subsequent field surveys revealed 14 additional localities, all within the Inyo Mountains, including 10 on the eastern slopes (Giuliani, 1977, 1988, 1990; Yanev and Wake, 1981; Papenfuss and Macey, 1986; Jennings and Hayes, 1994a). Northern range limits are Waucoba Canyon (2,285 m, east slope) and Barrel Spring (1,950 m, west slope); southernmost sites are Long John Canyon (1,695–1,830 m, west slope) and Hunter Canyon (490–915 m, east slope). The elevational range is from 490 (Hunter Canyon, east slope) to 2,590 m (upper Lead Canyon, east slope; Giuliani, 1977; Papenfuss, 1986).
All inhabited sites are highly localized—small areas of suitable habitat bordered by large expanses of inhospitable desert or semi-desert terrain. Inyo Mountains salamanders and desert slender salamanders (B. aridus) are the only salamanders that occur exclusively in desert ecosystems.
Occupied habitat for Inyo Mountains salamanders totals < 20 ha (Papenfuss and Macey, 1986; Giuliani, 1977). However, a few potential sites within the Inyo Mountains remain unsurveyed, and it is likely that additional populations will be found. Following surveys of eastern slope canyons of the Inyo Mountains, Giuliani (1977) estimated that potential habitat was present along about 19.2 linear km (11.9 mi).
2. Historical versus Current Abundance. Water diversion for mining or other activities has occurred at some sites, resulting in habitat degradation and possible extirpation of some populations (Papenfuss and Macey, 1986). This is especially severe for Barrel Spring (1,950 m), where the original 0.8-km- (0.5-mi-)long corridor of riparian habitat has been reduced 90% by water diversion and road construction (Giuliani, 1990). At Long John Canyon, flash flooding in 1985 caused a scouring of the canyon bottom, resulting in complete loss of riparian vegetation (Giuliani, 1990); the population appeared to be recovering slowly by 1995 (Giuliani, 1996). Considerable loss of riparian vegetation occurred at French Spring during flash flooding in 2001, although nearby salamander habitat was less affected (T. Russi, personal communication). Feral burros have degraded habitat at some sites (Giuliani, 1977; Papenfuss and Macey, 1986).
3. Life History Features.
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. Unknown.
ii. Breeding habitat. Unknown.
i. Egg deposition sites. Nests are unknown. Eggs are probably laid in moist crevices within the outcrops characteristic of Inyo Mountains salamander habitat.
ii. Clutch size. Unknown.
C. Direct Development. Eggs have not been recorded, but all species of Batrachoseps undergo direct development. A female found on 15 April at French Spring contained eggs visible through the abdomen.
D. Juvenile Habitat. Unknown how this may differ from adults. Both adults and juveniles have been found under rocks on wet substrates.
E. Adult Habitat. The Inyo Mountains are a north-south trending range, with east-west oriented canyons dissecting both slopes. Northern Mojave Desert vegetational associations (e.g., creosote bush scrub) occur at lower elevations, grading into Great Basin communities (sagebrush steppe and pinyon-juniper woodland) at higher elevations. Rainfall amounts range from 13 cm/yr at Independence in the adjacent Owens Valley (S. Hsu, personal communicaton) to approximately 22 cm/yr on the western slopes of the Inyo Mountains (Marlow et al., 1979). Perennial springs and seepages and their associated riparian plant species occupy discrete sections of steep-sided canyons; these areas are grown to willow, wild rose, and coyote brush, often forming dense thickets such that direct sunlight rarely reaches ground level. Salamander populations are largely restricted to such places, especially where solid-rock cliffs, outcrops, or talus are in contact with surface flow (Giuliani, 1977; Marlow et al., 1979; Macey and Papenfuss, 1991a). Salamanders have been found under rocks resting on wet substrates, sometimes under woody debris (which is relatively scarce), and occasionally within clumps of moist ferns growing in waterfall spray zones (Giuliani, 1977; Papenfuss and Macey, 1986). Fissures and crevices within the adjacent granitic or limestone outcrops also harbor salamanders and presumably serve as refugia during periods of unfavorable surface conditions. All records are from riparian sites except one—several specimens were found in pitfall traps positioned near openings in rock formations on a ridge (2,285 m) between two canyons. This suggests that at least at higher elevations within pinyon-juniper woodland, salamanders may not be restricted to canyon bottom, riparian habitats.
Salamanders have been found in every month, although snowfall and extreme cold undoubtedly restrict activity at higher elevation sites. Field body temperatures (inferred from substrate temperatures) ranged from 10.5–18.0 ˚C (Giuliani, 1977; R.W.H., unpublished data). Surface movements presumably occur at night.
F. Home Range Size. Unknown, but presumably small. Surface habitat at some sites is extremely limited, although including the moist crevices in adjacent outcrops may considerably expand the total available habitat.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. Perennial springs and seepages provide a moist, thermally buffered environment, such that surface activity is possible at most sites year-round. Water temperatures recorded from several springs where salamanders were found (at elevations of 490–2,590 m) ranged from 10.5–17.5 ˚C, with only modest seasonal variation (Giuliani, 1977). There was no correlation between elevation and water temperature.
I. Seasonal Migrations. Unknown.
J. Torpor (Hibernation). Unknown. Winter snowfall and low temperatures at higher elevation sites probably limit winter activity, although salamanders have been observed in December and January at moderately high elevations (1,765–1,950 m). Higher elevation sites are not accessible in winter.
K. Interspecific Associations/Exclusions. Inyo Mountains salamanders are the only salamanders within their range.
L. Age/Size at Reproductive Maturity. Females attain larger average and maximum size. The smallest sexually mature male known is 41.3 mm; average size of 27 sexually mature males was 46.9 mm SVL (maximum = 53.7 mm, Waucoba Creek, east slope). Smallest sexually mature female known is 43.8 mm SVL; average size of 29 sexually mature females was 51.6 mm SVL (maximum = 60.8 mm, Cove Creek, east slope).
M. Longevity. Unknown.
N. Feeding Behavior. Has not been described, although all Batrachoseps species observed thus far use a projectile tongue to capture small invertebrates.
O. Predators. Unknown.
P. Anti-Predator Mechanisms. Defensive behaviors include immobility (Marlow et al., 1979) and coiling in both juveniles and adults (R.W.H., unpublished data).
Q. Diseases. Unknown.
R. Parasites. Unknown.
S. Comments. Considerable genetic differentiation exists among populations currently recognized as B. campi, likely due to genetic drift and restricted gene flow together with small population sizes (Yanev and Wake, 1981). The genetic distance data, in conjunction with the extremely localized nature of potential habitat (Giuliani, 1977; Papenfuss and Macey, 1986), indicate that populations are currently genetically isolated from one another. The extreme fragmentation of the species is indicated by the high levels of FST (0.59) and low levels of Nm (on the order of 0.025 for the species; Larson et al., 1984). Extrapolating from these analyses, the collective effective population size of the populations sampled by Yanev and Wake (1981) was estimated at 14,000. Studies of mtDNA gene sequences, allozymes, and morphological data (Yanev, 1980; Jockusch, 1996; Jackman et al., 1997) confirm that B. campi, Oregon slender salamanders (B. wrighti), and Kern Plateau salamanders (B. robustus) from the southern Sierra Nevada are phylogenetically distant from other species of Batrachoseps.
4. Conservation. Papenfuss and Macey (1986) carefully detailed specific threats to each of the then-known populations of Inyo Mountains salamanders. Among these were mining activities (> 360 mining claims near B. campi populations), damage from livestock and feral burros, and water diversions. All localities occur on federal lands managed by the U.S. Bureau of Land Management or USDA Forest Service. Concerted efforts have been made by federal agencies to reduce the number of feral burros in the Inyo Mountains region. This is a Species of Special Concern (California Department of Fish and Game) and is listed as a Forest Service and BLM Sensitive Species.
Acknowledgments. Darrell Wong (California Department of Fish and Game) and Amy Kuritsubo (Bureau of Land Management) provided copies of unpublished reports. Simon Hsu of the Los Angeles Department of Water and Power provided rainfall data for the Owens Valley.
1 Robert W. Hansen
2 David B. Wake
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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