California tiger salamander
|California tiger salamander|
The California tiger salamander (Ambystoma californiense) is a vulnerable amphibian native to California. Previously considered to be a subspecies of the tiger salamander (A. tigrinum), the California tiger salamander was recently designated a separate species again. The California tiger salamander distinct population segment (DPS) in Sonoma County is listed as federally endangered, while the Santa Barbara County DPS and Central California DPS are federally threatened. The Sonoma County and Santa Barbara County DPS have been split from the rest of the California tiger salamander population for over one million years, and they may warrant status as separate species.
The California tiger salamander is a relatively large, secretive amphibian endemic to California. Adults can grow to a total length of about 7–8 inches. It has a stocky body and a broad, rounded snout. Adults are black with yellow or cream spots; larvae are greenish-grey in color. The California tiger salamander has brown protruding eyes with black irises.
Habitat and range
The California tiger salamander depends on vernal pools for reproduction; its habitat is limited to the vicinity of large, fishless vernal pools or similar water bodies. It occurs at elevations up to 1000 m (3200 ft). Adults migrate at night from upland habitats to aquatic breeding sites during the first major rainfall events of fall and early winter, and return to upland habitats after breeding.
Historically, the California tiger salamander probably occurred in grassland habitats throughout much of the state. It occurs from Sonoma County, especially in the Laguna de Santa Rosa (outside the floodplain), south to Santa Barbara County, in vernal pool complexes and isolated ponds along the Central Valley from Colusa County to Kern County, and in the coastal range. Both the Sonoma and Santa Barbara populations are listed as endangered since 2000 and 2003, respectively. On August 4, 2004, the US Fish and Wildlife Service listed the California tiger salamander as threatened within the Central Valley DPS. The Santa Barbara and Sonoma County populations were returned to endangered status on August 19, 2005.
The six populations are found in Sonoma County, the Bay Area (Stanislaus County, western Merced, and the majority of San Benito counties), the Central Valley, the southern San Joaquin Valley, the Central Coast Range, and Santa Barbara County.
The loss of California tiger salamander populations has been due primarily to introduced predators, such as American bullfrogs although habitat loss within their historic range, might also be an issue.
Adults spend the majority of their lives underground, in burrows created by other animals, such as ground squirrels and gophers; these salamanders are poorly equipped for burrowing. Little is known about their underground life. This underground phase has often been referred to as estivation (the summertime equivalent of hibernation), but true estivation has never been observed, and fiber optic cameras in burrows have allowed researchers to witness salamanders actively foraging. Adults are known to eat earthworms, snails, insects, fish, and even small mammals but adult California tiger salamanders eat very little.
Breeding takes place after the first rains in late fall and early winter, when the wet season allows the salamanders to migrate to the nearest pond, a journey that may be as far as a mile and take several days. The eggs, which the female lays in small clusters or singly, hatch after 10 to 14 days.
The larval period lasts for three to six months. However, California tiger salamander larvae may also "overwinter". Transformation for overwintering larvae may take 13 months or more. Recent discoveries, such as overwintering, have management implications for this threatened species, particularly when aquatic habitats undergo modification. The larvae feed on other small invertebrates, including tadpoles. When their pond dries, they resorb their gills, develop lungs, and then the metamorphs leave the pond in search of a burrow.
California tiger salamanders can live up to 15 years.
- Vernal pools or ponds
- California Natural Diversity Database California Natural Diversity Database
- Hammerson (2004). "Ambystoma californiense". IUCN Red List of Threatened Species. Version 2004. International Union for Conservation of Nature. Retrieved 17 February 2010.
- Shaffer, H. B. and S. Stanley. 1991. Final report to California Department of Fish and Game; California tiger salamander surveys, 1991 - Contract FG9422. California Department of Fish and Game, Inland Fisheries Division, Rancho Cordova, California.
- "Species Account: California Tiger Salamander". U.S. Fish and Wildlife Service. July 29, 2009. Retrieved February 17, 2010.
- California Tiger Salamander Endangered Species Facts (Report). Environmental Protection Agency. 2010-02. Retrieved 2013-03-14. Check date values in:
- Federal Register / Vol. 68, No. 53 / Wednesday, March 19, 2003 / Rules and Regulations Access date 2009 10 19 http://ftp.resource.org/gpo.gov/register/2003/2003_13498.pdf
- Shaffer, H. B. and P. C. Trenham. 2002. Distinct population segments of the California tiger salamander, Ambystoma californiense. Report to the USFWS.
- Fisher, R. N. and H. B. Shaffer. 1996. The decline of amphibians in California’s Great Central Valley. Conservation Biology 10:1387-1397.
- Center for Biological Diversity, Citizens for a Sustainable Cotati, Petitioners June 11, 2001. Accessed 2009 10 19 http://www.biologicaldiversity.org/species/amphibians/California_tiger_salamander/pdfs/PETITION.PDF
- CaliforniaHerps.com. Ambystoma californiense - California Tiger Salamander. Access 2009 10 19. http://www.californiaherps.com/salamanders/pages/a.californiense.html
- University of Michigan Animal Diversity Web: Ambystoma californiense, California tiger salamander. Accessed 2009 10 19. http://animaldiversity.ummz.umich.edu/site/accounts/information/Ambystoma_californiense.html
- T. Kucera, 1997 California Department of Fish and Game- California Wildlife Habitat Relationships System. Updated by: CWHR Program Staff, August 2005
- Stebbins, R. C. 1972. California amphibians and reptiles. Univ. California Press, Berkeley. 152 pp.
- Shaffer, H. B., R. N. Fisher, and S. E. Stanley. 1993. Status report: the California tiger salamander (Ambystoma californiense). Final report to the California Department of Fish and Game, Inland Fisheries Division, Rancho Cordova California, under Contracts (FG9422 and 1383)
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