Thomomys mazama couchi

endemic to a single state or province

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (<100 square km (less than about 40 square miles)) The range includes a small area in Mason County, southwestern Washington (Stinson 2005). The subspecies persists at the Scott's Prairie/Shelton airport site and perhaps 2 nearby areas (Stinson 2005). Steinberg (1996) found no trace of the T. m. couchi population at Lost Lake Prairie reported by Dalquest and Scheffer (1944), nor in Shelton Valley, Buck Prairie, Bulb Farm Rd, or in fields or roadsides around Satsop, Elma, and Cedarville. McKewen Prairie is mostly forested, with the last known gophers found only on a regenerating clearcut and along a road right-of-way (Stinson 2005). Steinberg reported possible gopher mounds on the grounds of the state penitentiary at Shelton, but this needs further investigation (Stinson 2005).

Comments: This fossorial rodent inhabits open grassy areas, including pastures, glacial outwash prairies, savannas, and open early seral woodlands and forests (Verts and Carraway 2000, Stinson 2005).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 1 - 5

Comments: Stinson (2005) mapped several (about 7) extant populations representing a few distinct population clusters and one historical location.

50 - 1000 individuals

Comments: Total adult population size is unknown but probably substantially less than 1,000 (see Stinson 2005).

United States

Rounded National Status Rank: N1 - Critically Imperiled

Rounded Global Status Rank: T1 - Critically Imperiled

Reasons: Very small range in prairie habitat in southwestern Washington; threatened by invasion of forest and non-native plant species into grassland habitat and loss of habitat to human uses.

Global Short Term Trend: Unknown

Comments: Trend is unknown but probably declining.

Global Long Term Trend: Decline of 70 to >90%

Comments: This pocket gopher no longer occus in a large proportion of its historical range (Stinson 2005).

Degree of Threat: Very high - high

Comments: This pocket gopher is threatened by loss of habitat, especially invasion of forest. The basic ecological processes that maintain prairies have disappeared from, or have been altered on, the few protected prairie sites. Fire regimes have been altered, and prairie habitat has been invaded by nonnative plant species (Dunn and Ewing 1997).

At Shelton Airport (Scott's Prairie), habitat now consists of mowed, non-native grassland; the Port of Shelton has plans to develop some of this area over the next several years (Stinson 2005). At McKewan Prairie, the habitat is now mostly forested, including a commercial forest in the seedling stage (Stinson 2005). At Johns Prairie, the habitat is now forest and an industrial park invaded by Scotch broom and other weeds (Stinson 2005). Lost Lake Prairie has thin rocky soil and sparse vegetation, and was rapidly being overgrown by forest when gophers were trapped there several decades ago (see Stinson 2005).

Global Protection: None. No occurrences appropriately protected and managed

Comments: One population occurs on airport land; additional patchy populations may exist on nearby private lands.

Stewardship Overview: See information for Thomomys mazama.