The northwestern salamander (''Ambystoma gracile'') is a species of mole salamander that inhabits the northwest Pacific coast of North America. These fairly large salamanders grow to 8.7 in (220 mm) in length. It is found from southeastern

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

on May Island, through Washington and

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

south to the mouth of the Gualala River,

Sonoma County Sonoma County ( ) is a county located in the U.S. state of California. As of the 2020 United States census, its population was 488,863. Its seat of government and largest city is Santa Rosa. Sonoma County comprises the Santa Rosa-Petaluma ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It occurs from sea level to the timberline, but not east of the Cascade Divide. Its range includes

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

and The San Juan Islands, Cypress, Whidbey, Bainbridge, and Vashon Islands in Washington.Snyder, R.C. 1963. Ambystoma gracile. Catalogue of American Amphibians and Reptiles: 1-2.

Description

The egg mass is very firm, it feels much like a brain with a jelly layer around the entire mass. The individual eggs are 2 mm diameter with the entire egg mass the size of your fist. The egg masses are laid in water about 0.5– 2 meters below the surface. The hatchlings are 1-35mm long with feathery gills on the side of the body. The juveniles are 16– 105 mm long from their snout to vent. Adults are 40–107 mm long from their snout to vent.

Distribution and habitat

The spotted forms occur in the northern portion of its range.Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London. A dividing line of 51°N latitude has been recognized between the two subspecies, with ''A. g. decorticatum'' occurring north of the line and ''A. g. gracile'' living to the south. Populations with neotenic adults are widespread; the frequency of

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

ed adults increases with altitude such that adults at low and intermediate altitudes are almost all terrestrial, while adults at very high elevations are mostly neotenic. An example of a paedomorphic population of the northwestern salamander occurs at Crater Lake,

; the population is syntopic with '' Taricha granulosa''. Terrestrial adults live in

mesic habitat In ecology, a mesic habitat is a type of habitat with a well-balanced or moderate supply of moisture throughout the growing season (e.g., a mesic forest, temperate hardwood forest, or dry-mesic prairie). The term derives from the Greek ''mesos'' ...

s ranging from grasslands to mesophytic forests. Terrestrial adults are mostly

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

, and are usually active on the surface only during fall rains and spring migrations to their aquatic breeding sites. However, they can sometimes be found under logs and other surface debris outside of the breeding season. Adult salamanders eat small terrestrial invertebrates such as insects, worms, and arachnids. Larvae and juveniles consume aquatic invertebrates including snails, worms, and tadpoles.

Conservation

The conservation status of ''Ambystoma gracile'' populations is unknown. No declines are apparent in

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. In the Cascade Mountains of Washington, ''A. gracile'' is far less abundant in young forests than in old-growth forests. However, a survey in western Oregon found little correlation between salamander abundance and stand age, so it remains unclear whether ''A. gracile'' requires

old growth forest An old-growth forest or primary forest is a forest that has developed over a long period of time without disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Natio ...

to thrive.Corn, P. S. and Bury, R. B. (1991). ''Terrestrial amphibian communities in the Oregon Coast Range.'' Wildlife and Vegetation of Unmanaged Douglas-fir Forests, General Technical Report PNW-GTR-285. K. Ruggiero, B. Aubry, A. B. Carey, and M. H. Huff, technical coordinators, eds., USDA Forest Service, Pacific Northwest Research Station, Olympia, Washington., 304-317. Clear-cutting, however, seems to render the habitat unsuitable; no salamanders were found on recent clear-cuts. Leaving a forest buffer of 200–250 m surrounding breeding sites used by terrestrial adults may preserve optimal environmental conditions for local populations.

References

{{Taxonbar, from=Q1945272 Mole salamanders Amphibians described in 1859 Taxa named by Spencer Fullerton Baird