San Bernadino Mountains Bladderpod

Lesquerella kingii ssp. bernardina

Description

San Bernadino Mountains bladderpod, Lesquerella kingii ssp. bernardina, is a short-lived perennial of the mustard family (Brassicaceae or Cruciferae) that reaches 4-8 in (10-20 cm) in height. The silvery plant has yellow flowers located toward the ends of the stems. The basal leaves are ovate and have long petioles.

Habitat

The habitat for the San Bernadino Mountains bladderpod is characterized by carbonate substrates, either brown sandy soils with white carbonate rocks or outcrops of large carbonate rock. All populations of the species, both in the Bertha Ridge and the Sugarlump Ridge areas, occur on dolomite on north-and south-facing slopes of gentle to moderation inclination at elevations between 6,800 and 8,800 ft (2,040 and 2,640 m). The subspecies is found in open areas with little accumulation of organic material within Jeffrey pine-western juniper woodlands, as well as white fir forest in some locations. The plant seems to be tolerant of slight disturbance; in 1988, scattered plants were found growing on old roads, undeveloped lots, and undeveloped yards within the Whispering Forest housing tract. However, the plant is conspicuously absent from heavily graded and mulched ski runs in the Bear Mountain ski area.

Distribution

San Bernadino Mountains bladderpod is currently known from two areas on either side of Bear Valley. The cluster of occurrences on the north side of the valley, near the east end of Bertha Ridge and adjacent to the community of Big Bear, is subject to impacts from urbanization. The other cluster is centered on the north-facing slope of Sugarlump Ridge to the south of the valley, approximately 6 mi (9.5 km) south of the Bertha Ridge occurrences. These latter occurrences were discovered during the spring of 1990 on an existing downhill ski run, as well as on and adjacent to proposed ski runs and lift lines within an existing ski area.

The estimate of total number of individuals in the Bertha Ridge occurrences was 25,000 in 1980 and less than 10,000 in 1988; it is unclear whether this was due to differences in sampling techniques or drought conditions. In 1991, the Sugarlump Ridge populations totaled approximately 10,000 individuals. Near the east end of Bertha Ridge, the southernmost population of Cushenbury buckwheat occurs in close proximity to one colony of San Bernadino Mountains bladderpod.

The significant drop in the size of San Bernadino Mountains bladderpod populations in the Bertha Ridge area between 1980 and 1988 from 25,000 to 15,000 individuals may be in part due to several years of drought conditions.

Threats

San Bernadino Mountains bladderpod is restricted primarily to carbonate and adjacent carbonate/granitic substrates occupied by pinyon-juniper woodland on the northern side of the San Bernardino Mountains. The imminent and primary threat facing this species is the ongoing destruction of the carbonate substrates on which it grows by activities associated with limestone mining, including direct removal of mined materials, disposal of over-burden on adjacent unmined habitat, and road construction. Additional threats to its habitat include off-highway vehicle use, urban development near the community of Big Bear, development of a ski run, and energy development projects.

Conservation and Recovery

The San Bernadino Mountains bladderpod is known from only two areas, each comprising a local cluster of populations occurring on suitable habitat. Its critical habitats are privately owned, and are potentially threatened by mining, residential and commercial development, trampling, and other disturbances. The largest critical habitats in both areas should be protected. This could be done by acquiring the habitats and designating them as ecological reserves, or by negotiating conservation easements with the landowners. The populations of the San Bernardino Mountains bladderpod should be monitored, and research undertaken into its basic biology and ecological requirements.

Contact

U.S. Fish and Wildlife Service
Ventura Field Office
2493 Portola Road, Suite B
Ventura, California 93003-7726
Telephone: (805) 644-1766

References

U.S. Fish and Wildlife Service. 24 August 1994. "Endangered and Threatened Wildlife and Plants; Five Plants From the San Bernardino Mountains in Southern California Determined to be Threatened or Endangered." Federal Register. http://endangered.fws.gov/r/fr94548.html