Vail Lake Ceanothus

Ceanothus ophiochilus

Description

Ceanothus ophiochilus (Vail Lake ceanothus), a member of the buckthorn family (Rhamnaceae), was described by Steve Boyd, Timothy Ross, and Laurel Arnseth based on a collection made by the authors in March 1989 west of Vail Lake in Riverside County, California. This classification of the species is accepted in the most recent taxonomic treatment of the genus.

C. ophiochilus is a rounded, divaricately branched (widely forked) shrub, 4-5 ft tall (1.2-1.5 m). The leaves are opposite, thick, 0.1-0.3 in (3-7 m) long and less than 0.1 in (2.5 mm) wide. The stipules are corky. The fruits are 0.1 in (3-3.5 mm) in diameter, and usually hornless. C. ophiochilus lacks a burl and recovers after fire by means of seed germination. C. ophiochilus is differentiated from other species of Ceanothus in the area by its opposite, narrow leaves, pale green color below, blue flowers, and hornless fruits. This species grossly resembles Adenostoma fasciculatum (chamise), the codominant shrub in its habitat. C. ophiochilus flowers from mid-February to March and the seed capsules mature from about May to mid-June.

Habitat

Vail Lake ceanothus occurs in restricted, localized populations in the interior foothills of Los Angeles, Riverside and San Bernardino Counties in California. C. ophiochilus is found in chamise chaparral, often in association with specific soil types. C. ophiochilus is restricted to dry habitats on ridgetops and north to northeast facing slopes in chamise chaparral. It occurs on shallow soils formed from ultra-basic parent materials or deeply weathered gabbro, both of which are phosphorus deficient. Nutrient poor soils may be critical for the species to maintain reproductive isolation. C. ophiochilus appears to hybridize with the locally common C. crassifolius in places where the two species occur together.

Chaparral habitats of the interior foothill region of southern California are dense shrub associations of moderate height dominated by chamise, California lilac, red berry, manzanita, California scrub oak, sugar bush, laurel sumac, toyon, California buckwheat, and black sage. Chaparral plant communities are adapted to nutrient poor soils, cool wet winters, and hot dry summers.

Distribution

Population centers for C. ophiochilus are located near Vail Lake in southwestern Riverside County. Small populations of C. ophiochilus occur just south of Vail Lake in the Agua Tibia Wilderness of the Cleveland National Forest.

C. ophiochilus is found at three sites in southwestern Riverside County. These populations are scattered along borders of creeks and dry canyons, sometimes on gabbro soils. One population of 3,000-5,000 plants occupies about 20 acres (8 hectares) within a 40-acre (16-hectare) area of seemingly suitable habitat on privately owned land at Vail Lake. There are some hybrid individuals in this population. The remaining two populations exist on land managed by the U. S. Forest Service, where over 4,000 plants exist in a 30-acre (12-hectare) area of the Agua Tibia Wilderness Area. The two populations in the Agua Tibia Wilderness occupy about 50% of the known occupied habitat of the species and contain a significant number of individuals, and the Vail Lake population includes the other 50% of the known occupied habitat and plants. Both Agua Tibia populations appear to contain hybrid plants. A portion of one of these populations consists of plants that are too young to determine the degree of hybridization taking place. Although all three populations contain some individuals that evidently are not pure C. ophiochilus, the Service continues to recognize their importance to the long-term survival of the species. Hybridization is a natural phenomenon common among the species of Ceanothus. Conservation of the hybrid plants will be addressed in the recovery plan for C. ophiochilus.

Threats

This species is imperiled by various activities, including urbanization and off-road vehicle use, that result in habitat modification, destruction, degradation, and fragmentation. The specific soil and/or hydrological requirements of these plant species naturally limit their distribution to clay soils formed from gabbro and alluvial or sedimentary based substrates (sandy washes and terraces) within the chaparral or scrub plant communities. Most of the alluvial scrub habitat in the San Fernando and San Gabriel valleys has been eliminated by urban development, road widening, flood control measures or habitat degradation from extensive recreational use. Urban development and mining have generally impacted these habitat types more directly than other activities within the chaparral community, the terrain being more accessible than the typically rugged, steep, boulder-covered terrain of the surrounding chaparral.

U. S. Fish and Wildlife Service (FWS) finds that C. ophiochilus is likely to become endangered within the foreseeable future throughout all or a significant portion of its range if identified threats are not reduced or eliminated. Threats to this species include habitat destruction, alteration, fragmentation, and degradation from urban development, as well as alteration of fire regimes; the species is fire-dependent for successful proliferation, and disruption of the natural fire regime can disrupt or eliminate seedling establishment.

Conservation and Recovery

FWS is working with Riverside and San Bernardino Counties to create multispecies habitat conservation plans that may benefit C. ophiochilus and Berberis nevinii. San Bernardino County and Riverside County have signed planning agreements with local, State and Federal agencies including the Service. Although this planning process is ongoing and the protection to be provided for these species is yet to be established, such multispecies plans can provide significant protection to both species.

In the spring of 1995, as previously noted, the landowner of the Vail Lake Planned Community Area offered the Riverside County Habitat Conservation Agency (RCHCA) an option to acquire about 6,000 acres (2,428 hectares), including the C. ophiochilus population, as part of a conservation bank. The option expired in September 1995, and all of these remaining parcels were recently sold. Subsequently, a conditional use permit was requested for one of the parcels containing Dodecahema leptoceras, a federally listed endangered species. This parcel contains an RV park and is adjacent to the parcel where the population of C. ophiochilus is located. This population comprises about one-half of the known individuals of C. ophiochilus.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

U. S. Fish and Wildlife Service
Carlsbad Field Office
2730 Loker Avenue West
Carlsbad, California 92008-6603
Telephone: (760) 431-9440
Fax: (760) 431-9624

Reference

U. S. Fish and Wildlife Service. 13 October 1998. "Endangered or Threatened Status for Three Plants from the Chaparral and Scrub of Southwestern California." Federal Register 63(197): 54956-54971.