Sacramento Orcutt Grass
Sacramento Orcutt Grass
|Listed||March 26, 1997|
|Description||A densely tufted, annual grass.|
|Threats||Habitat destruction by urban and commercial development, and competition with invasive alien plants.|
Sacramento orcutt grass, Orcuttia viscida, is a densely tufted, pilose annual that reaches 1-4 in (2.5-10 cm) in height. The erect stems terminate in spike-like inflorescences that are congested at the apex. The plants are viscid even when young and more so at maturity. Sacramento orcutt grass develops five-toothed lemmas 0.2-0.3 in (5-7.5 mm) long with the middle tooth conspicuously longer than the four laterals. The lemma teeth curve outward at maturity, giving the inflorescence a distinct bristly appearance. Although O. viscida is geographically isolated from all other members of the genus, it most closely resembles O. inaequalis, from which it can be distinguished by the description in the article on the latter taxon.
Sacramento orcutt grass possesses the narrowest range of these eight listed species. This taxon occurs within a 135 sq mi (351 sq km) area in eastern Sacramento County, and only 18 mi (29 km) separates the northernmost from the southernmost population. Two of the nine known populations have been extirpated, leaving three populations on private lands and four on non-Federal public lands. These last consist of one population each on land owned by a public municipality, by the County of Sacramento, by the City of Fair Oaks, and by the California Department of Fish and Game.
The Sacramento orcutt grass occurs in vernal pools, which are wet in the winter and early spring, but then progressively dry during the late spring and summer.
The Sacramento orcutt is a local (or endemic) species that only occurs within an area of about 135 sq mi (350 sq km) in eastern Sacramento County, California.
Sacramento orcutt grass is chiefly threatened by habitat destruction brought about through urban development. Two of the nine known populations have been extirpated. Of the seven extant populations, five are variously threatened by urban development, competition from non-native weeds, and a landfill project.
At least 10 proposed housing developments, golf courses, and landfills in the Sacramento and San Joaquin valleys threaten vernal pool areas that may provide suitable habitat for Sacramento orcutt grass. Although one population in eastern Sacramento County is within a preserve, it remains threatened by a proposed subdivision. Three proposed gravel and aggregate mining projects, two in Sacramento County and one in Fresno County, threaten to destroy vernal pool habitat containing this species. One of the seven Sacramento County populations of this plant is threatened by a public landfill expansion.
The distribution and abundance of Sacramento orcutt grass at six of the seven extant sites is significantly restricted by Eleocharis macrostachya, which appears to threaten one population of this taxon through competitive exclusion.
Conservation and Recovery
Four of the seven surviving populations of the Sacramento orcutt grass are located on non-federal public lands. One critical habitat is owned by a municipality, one by the County of Sacramento, one by the City of Fair Oaks, and one by the California Department of Fish and Game. These publicly owned habitats should be protected from urbanization and other threatening developments. Three additional populations are found on private lands, and are at risk from development and other disturbances. These habitats should be acquired and designated as ecological reserves, or conservation easements negotiated with the landowners. The populations of the Sacramento orcutt grass should be monitored, and research undertaken into its basic biology and ecological requirements.
U.S. Fish and Wildlife Service
Sacramento Fish and Wildlife Office
2800 Cottage Way, Room w-2605
Sacramento, California 95821-1846
Telephone (916) 414-6600
Fax: (916) 480-4619
U.S. Fish and Wildlife Service. 26 March 1997. "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Plants and Threatened Status for Five Plants From Vernal Pools in the Central Valley of California." Federal Register 62 (58): 14338-14352.