|Scientific Name:||Dicamptodon ensatus|
|Species Authority:||(Eschscholtz, 1833)|
Triton ensatus Eschscholtz, 1833
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Geoffrey Hammerson, Bruce Bury|
|Reviewer(s):||Global Amphibian Assessment Coordinating Team (Simon Stuart, Janice Chanson, Neil Cox and Bruce Young)|
Listed as Near Threatened because although the species might not to be in decline, its Extent of Occurrence is much less than 20,000 km2, thus making the species close to qualifying for Vulnerable.
|Range Description:||This species can be found in west-central California, USA (Good 1989). It also occurs from Sonoma and Napa Counties south to Santa Cruz County and to Monterey County (Petranka 1998). It is found from 0-900m asl.|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total adult population size is unknown but is likely to be at least several thousand. It is locally abundant (J.W. Petranka pers. comm.), but terrestrial adults are far less abundant than the aquatic larvae (Petranka 1998). No population data are available to determine trends in its population status (D.B. Wake pers. comm.).|
|Habitat and Ecology:||Larvae of this species usually inhabit clear, cold streams, but are also found in mountain lakes and ponds. Adults are found in humid forests under rocks and logs, for example, near mountain streams or rocky shores of mountain lakes (Stebbins 1985b). Eggs are usually laid in the headwaters of mountain streams. Breeding typically occurs in water-filled nest chambers under logs and rocks or in rock crevices.|
|Major Threat(s):||The greatest threats to this species are stream siltation and urban development (Petranka 1998; D.B. Wake pers. comm.), and it is also threatened by habitat fragmentation due to land use changes, including urbanization, agricultural development, and logging (H.H. Welsh pers. comm.). In the related Pacific giant salamander (D. tenebrosus), larvae may be reduced in numbers where there has been clear-cut logging (Corn and Bury 1989) or siltation from roads (Welsh and Ollivier 1998). However, opening of forest canopies over streams might lead temporarily to higher primary productivity that in turn increases the body sizes of larval D. tenebrosus (Murphy and Hall 1981).|
|Conservation Actions:||Dicamptodon ensatus occurs in numerous protected areas, and is therefore probably only moderately threatened, even though its range is small and close to urban areas.|
Anderson, J.D. 1968. Dicamptodon , D. ensatus. Catalogue of American Amphibians and Reptiles: 1-2.
Blackburn, L., Nanjappa, P. and Lannoo, M.J. 2001. An Atlas of the Distribution of U.S. Amphibians. Ball State University, Muncie, IN, USA.
Bury, R.B. 2005. Dicamptodon ensatus Good, 1989: California Giant Salamander. In: Lannoo, M.J. (ed.), Status and Conservation of U.S. Amphibians. Volume 2: Species Accounts, University of California Press, Berkeley, California.
Corn, P.S. and Bury, R.B. 1989. Logging in western Oregon: responses of headwater habitats and stream amphibians. Forest Ecology and Management: 39-57.
Daugherty, C.H., Allendorf, F.W., Dunlap, W.W. and Knudsen, K.L. 1983. Systematic implications of geographic patterns of genetic variation in the genus Dicamptodon. Copeia: 679-691.
Frost, D.R. 1985. Amphibian Species of the World: A Taxonomic and Geographic Reference. Allen Press and the Association of Systematic Collections, Lawrence, Kansas.
Good, D.A. 1989. Hybridization and cryptic species in Dicamptodon (Caudata: Dicamptodontidae). Evolution: 728-744.
IUCN. 2004. 2004 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 23 November 2004.
Murphy, M.L. and Hall, J.D. 1981. Varied effects of clear-cut logging on predators and their habitat in small streams of the Cascade Mountains, Oregon. Canadian Journal of Fisheries and Aquatic Sciences: 137-145.
Nussbaum, R.A. 1969. Nests and eggs of the Pacific giant salamander, Dicamptodon ensatus (Escholtz). Herpetologica: 257-262.
Nussbaum, R.A. 1976. Geographic variation and systematics of salamanders of the genus Dicamptodon Strauch (Ambystomatidae). University of Michigan, Museum of Zoology, Miscellaneous Publication: 1-94.
Nussbaum, R.A. and Clothier, G.R. 1973. Population structure, growth, and size of larval Dicamptodon ensatus (Erscholtz). Northwest Science: 218-227.
Nussbaum, R.A., Brodie, Jr., E.D. and Storm, R.M. 1983. Amphibians and Reptiles of the Pacific Northwest. University Press of Idaho, Moscow, ID, USA.
Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, D.C.
Stebbins, R.C. 1985. A Field Guide to Western Reptiles and Amphibians. Second Edition. Houghton Mifflin Company, Boston, Massachusetts.
Welsh, H H., Jr. and Ollivier, L.M. 1998. Stream amphibians as indicators of ecosystem stress: a case study from California's redwoods. Ecological Applications: 1118-1132.
|Citation:||Geoffrey Hammerson, Bruce Bury 2004. Dicamptodon ensatus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 29 July 2015.|