This species' range includes several springs feeding Deep Springs Lake, in Deep Springs Valley, Inyo County, California, USA: Buckhorn Spring, Corral Spring and adjacent ponds, and Bog Mound Springs at about 1,520m; also Antelope Springs at about 1,710m (Murphy, Simandle and Becker 2003, Stebbins 2003). Apparently, this species was introduced to a flowing well in Saline Valley, Death Valley National Park, Inyo County, California (Murphy, Simandle and Becker 2003), and also introduced at Batchelder Spring, Westgard Pass, Inyo County, but is possibly extirpated there.
Habitat and Ecology
Its primary habitat is watercourses/marshes (grass, sedge, dwarf bulrush, and watercress), formed by water flow from springs, and surrounded by desert with low bushes. Adults are more aquatic than other toad species in California. Adults prefer habitats with short plant cover and unobstructed access to still or slowly flowing water (Schuierer and Anderson 1990). It retreats to rodent burrows or other refuges in winter. It breeds in shallow marsh and pond waters (Schuierer and Anderson 1990).
The population of this species was regarded as more or less stable in the early 1970s (Bury, Dodd and Fellers 1980), and no significant change was reported in 1990 (California Department of Fish and Game 1990, Schuierer and Anderson 1990). The population at Antelope Springs (apparently introduced) was reported to have died out (Stebbins 1985b), but is still referred to by both Murphy, Simandle and Becker (2003) and Stebbins (2003). Historical population data is as follows: over 4,000 individuals (1971 survey), more than 80,000 individuals (1977 estimate). The population at Corral Spring(s) was reported in 1980 as more than 22,000 (Sherman 1980).
At present, there do not appear to be any major threats to this species. However, potential future threats include habitat destruction from irrigation schemes or other factors resulting in water table alteration, recreational vehicle use, cattle overgrazing, and predation by carp.
The Department of Fish and Game has purchased 719 acres to protect the habitat at Deep Springs; Deep Spring College (owner of property at Buckhorn and Antelope springs) has fenced an area to exclude livestock and is manipulating irrigation water to minimize impacts on breeding toads, eggs, and larvae (California DF&G 1990). Other sites are on BLM land, but the level of protection is uncertain.
Red List Status
Listed as Vulnerable because its area of occupancy is less than 20 km2.
Molecular data suggest that this species might be conspecific with Anaxyrus canorus, but this requires further investigation.
Geoffrey Hammerson 2004. Anaxyrus exsul. The IUCN Red List of Threatened Species 2004: e.T3169A9647112. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T3169A9647112.en .Downloaded on 14 December 2018