The Siskiyou mariposa lily became a candidate species in June 2002. An annual review of the species' status was conducted in Decmeber 2007.

Historical Status and Current Trends

The Siskiyou mariposa lily (Calochortus persistens) is listed as a sensitive species by the USDA Forest Service in their Region 5, and listed as a rare species by the state of California (California Department of Fish and Game 2006).  The Oregon Department of Agriculture does not include Siskiyou mariposa lily on the state of Oregon's threatened or endangered plant list.  However the Oregon Natural Heritage Information Center ranks Siskiyou mariposa lily as an S1 species, i.e., critically imperiled statewide (Oregon State University 2006).

Description and Life History

Siskiyou mariposa lily (Family Liliaceae) is an herbaceous perennial with a single, basal leaf arising from a bulb.  The basal leaf can be up to 20 centimeters (7.9 inches) in length and the flowering stem approximately 10 centimeters (3.9 inches) high.  One to two large showy, pink to lavender, erect, bell-shaped flowers have a yellow fringe above the nectary at the base of the petals (Ownbey 1940).

Habitat

In Oregon, the habitat is similar to the habitat of the California populations.  Siskiyou mariposa lily is found at 1,707 meters (5,600 feet) in McMullin Rock Outcrop Complex soils, which are also shallow talus soils (B. Tong in litt. 2006).   In Oregon, Siskiyou mariposa lily is found in an open rock outcrop barren associated with Ponderosa pine, ocean spray, Fremont’s silk tassel, bitter cherry, Idaho fescue, lace lipfern, and wild buckwheat species (B.Tong in litt. 2006).

In California, Siskiyou mariposa lily occurs at elevations of 1,310 meters (4,300 feet) to 1,847 meters (6,060 feet) on ridgeline rock outcrops and talus, where the soils are shallow, dry, rocky, and acidic (Klamath National Forest 1987, Klamath-Siskiyou Wildlands Center et al. 2001).  These soils are well drained and dry early in the season after snowmelt.  Siskiyou mariposa lily plants are found in greater numbers on north-facing slopes.  The plants are almost entirely restricted to the rockiest portions of the ridge tops and ridge shoulders, and do not extend very far down the associated slopes. 

Range

Siskiyou mariposa lily is a narrow endemic that occurs in the Klamath-Siskiyou Range, on the California-Oregon border and in a few locations in southern Oregon.  In California, this species is currently found at ten separate sites in the Klamath National Forest and privately-owned lands along the Gunsight-Humbug Ridge.  Oregon populations are located near Bald Mountain of Jackson County but an extirpated population once occurred on Red Mountain near the Oregon–California Border.

Reasons for Decline

Industrial, commercial, and residential development, road and power-line construction and maintenance, livestock grazing, agricultural conversion, weed competition, mowing, and roadside spraying have all contributed to the decline of this species.

Conservation Measrues

The Fish and Wildlife Service and the Medford District of the Bureau of Land Management have funded efforts to document the Siskiyou mariposa lily’s location, monitor the health of the population and evaluate potential threats to its continued existence.  Additionally, surveys in suitable habitat in the Bald Mountain area for currently undocumented populations of the Siskiyou mariposa lily will be accomplished in 2008 through 2010.

References and Links

Klamath National Forest.  1987.  Calochortus persistens habitat inventory and status investigation. Unpublished report prepared for the Klamath National Forest, Yreka, California.  July 27, 1987.  5 pp. + appendices. 

Klamath-Siskiyou Wildlands Center, Oregon Natural Resources Council, and B. Knapp.  2001.  Formal petition to list the Siskiyou mariposa lily endangered under the Endangered Species Act. Ashland, Oregon.  20 pp. + appendices.

Ownbey, M.  1940.  A monograph of the genus Calochortus. Annals of the Missouri Botanical Garden, vol. 27. no. 4.  November 1940.

Oregon State University.  2006.  Oregon Natural Heritage Information Center.

Tong, B.  2006.  Email with attachment from Brad Tong, U.S. Department of the Interior, Bureau of Land Management, Medford, Oregon, to Marla Knight, Klamath National Forest.  May 31, 2006.

U.S. Fish and Wildlife Service (USFWS).  2002.  Endangered and threatened wildlife and plants; Review of species that are candidates or proposed for listing as endangered or threatened; Annual notice of findings on recycled petitions; annual description of progress on listing actions. FR 67:40657-40679.  June 13, 2002.