Vail Lake ceanothus Ceanothus ophiochilus Class: Magnoliopsida Order: Rhamnales Family: Rhamnaceae Dudek and Associates Species Accounts Status: Federal: Threatened State: Endangered Data Characterization Data reviewed includes the University of California, Riverside, GIS database, the California Natural Diversity Database (CNDDB) and available literature. The CNDDB and UCR databases each include three mapped locations. The mapped locations of the databases are concurrent at one location (Vail Lake) and differ slightly at the other two mapped locations. The mapping data for the Agua Tibia Wilderness population are inaccurate; the population lays about one or two miles south of the mapped location. The listing rule from the U.S. Fish and Wildlife Service (1998), species monograph (Boyd, et al. 1991) and an unpublished report from California Department of Fish and Game (1993) provided the majority of information available for this species for habitat and habitat associations, species range and distribution and threats to the species. Species-specific studies for reproductive biology, pollinators, dispersal, etc., have not been conducted for this species. Habitat and Habitat Associations This species is found in dry habitats along ridgetops and north to northeast-facing slopes in chamise chaparral (Boyd, et. al. 1991). Vail Lake ceanothus is restricted to shallow soils originating from ultra-basic parent rock and deeply weathered gabbro, which are both phosphorous-deficient (Boyd, et al. 1991; Bauder 1998). Biogeography Vail Lake ceanothus is endemic to southwestern Riverside County, specifically Vail Lake and the Agua Tibia Wilderness of the Cleveland National Forest (Boyd, et. al. 1991; Schmidt 1993; U.S. Fish and Wildlife Service 1998). Range Vail Lake Ceanothus is restricted to three populations in the hills immediately west of Vail Lake and on the north slope in the Agua Tibia Wilderness on lower, north-facing slopes of Agua Tibia Mountains (Boyd, et al. 1991; CNDDB 1998; U.S. Fish and Wildlife Service 1998). About half the individuals are within one population on private land (Vail Lake) and the other half are dispersed over two populations within the Agua Tibia Wilderness Area (U.S. Fish and Wildlife Service 1998). The population at Vail Lake is estimated to be 3,000 to 5,000 plants (California Department of Fish and Game 1993). Within the Agua Tibia Wilderness Area, population estimates for the northern stand are 2000-4000 and for the southern stand are 6,000 to 12,000 (Boyd and Banks 1995). Key Populations in Planning Area Due to the limited numbers and range of Vail Lake Ceanothus, all three existing populations (the hills immediately west of Vail Lake and on the lower, north-facing slopes of the Agua Tibia Mountains in the Agua Tibia Wilderness) are considered key populations. Biology Genetics: Vail lake ceanothus is able to hybridize with Ceanothus crassifolius (Boyd, et al. 1991) and hybrids have been observed at all three populations (U.S. Fish and Wildlife Service 1998). While the hybrid individuals at Vail Lake are limited to the margins, the hybridization rate is much higher for the Agua Tibia Wilderness Area populations: more than 50% of the northern Agua Tibia population exhibits intermediate characteristics (Boyd and Banks 1995). Reproduction: Vail Lake ceanothus produces umbel-like clusters of pale blue (rarely pinkish lavender) flowers from mid-February to March (Boyd, et al. 1991). Published literature regarding pollinators is not available for this species. The genus Ceanothus is a generalist regarding pollinators: copious small pollinators such as beetles and wasps were observed inside flowers in the field (Clifford Schmidt, pers. comm., 1999). This species lacks a burl and does not reproduce vegetatively after a wildfire. An obligate seeder, this species is dependent on occasional fires for seed germination (Boyd, et al. 1991). Dispersal: The seed pods of this genus mature from late-May to mid-June, building up tension as they ripen and flinging their seed in all directions as the pods dehisce (Smith 1994). Threats Threats to this species include habitat alteration, fragmentation, destruction and degradation from urban development, as well as fire regime alteration. The Vail Lake population is within an area that has been proposed for development several times in recent years (U.S. Fish and Wildlife Service 1998). Development is expected to increase the frequency of wildfires which is a threat to this fire-dependent species. A high frequency fire regime would first eliminate older plants and then eliminate younger plants before they reach reproductive maturity, thus depleting the seed bank and disrupting or eliminating seedling establishment (Boyd et al. 1991; California Department of Fish and Game 1993; U.S. Fish and Wildlife Service 1998). Special Biological Considerations Vail Lake ceanothus lacks a burl and appears to recover from fire by seed germination (Boyd, et al. 1991). This species blooms from mid-February to March. Fruit matures late May to mid-June and is readily detectable year-round. Outside of the flowering period, it is difficult to differentiate Vail Lake ceanothus from surrounding Adenostoma. Vail Lake ceanothus is able to hybridize with Ceanothus crassifolius where the two species occur together: nutrient poor soils, to which C. crassifolius does not appear to be adapted, may therefore be critical to maintain Vail Lake ceanothus in isolation (Boyd, et al. 1991). Symbiotic relationships between Ceanothus species and Frankia, a nitrogen-fixing actinomycete fungus, and endo- and ectomycorrhizae fungi are widespread (Clifford Schmidt, pers. comm., 1999). Literature Cited Bauder, E. 1998. Exotics of Southern California's vernal pools and other specialized habitats. Boyd, S., T. Ross and L. Arnseth. 1991. Ceanothus ophiochilus (Rhamnaceae): A Distinctive, Narrowly Endemic Species from Riverside County, California. Phytologia 70(1):28-41. Boyd, S. and D. Banks. 1995. A Botanical Assessment of the Agua Tibia Wilderness Area, Cleveland National Forest, California. Rancho Santa Ana Botanic Garden, Claremont, California. 89 pp. California Department of Fish and Game. 1993. Report to the Fish and Game Commission on the Status of Vail Lake Ceanothus (Ceanothus ophiochilus). Unpublished report, Natural Heritage Division. California Department of Fish and Game, Sacramento, California. California Natural Diversity Data Base. 1998. Ceanothus ophiochilus. Unpublished report, Natural Heritage Division, California Department of Fish and Game, Sacramento, California. Schmidt, C.L. 1993. Ceanothus, pp. 932-938 in Hickman, J.C., editor, The Jepson Manual: Higher Plants of California. University of California Press, Berkeley. Skinner, M.W. and B.M. Pavlik. 1994. California Native Plant Society's Inventory of Rare and Endangered Vascular Plants of California. Special Publication No. 1, 5th edition. California Native Plant Society, Sacramento. Smith, N. 1994. Growing Natives: The Smaller Ceanothus. Fremontia 11(4):27-28. U.S. Fish and Wildlife Service. 1998. Endangered and threatened wildlife and plants; endangered or threatened status for three plants from chaparral and scrub of southwestern California. Federal Register 63:54956