Nevin's barberry Berberis nevinii Class: Magnoliopsida Order: Ranunculales Family: Berberidacea Dudek and Associates Species Accounts Status: Federal: Endangered (1998) State: Endangered Data Characterization Data reviewed includes the University of California, Riverside, GIS database, the California Natural Diversity Database (CNDDB) and available literature. The University of California, Riverside, GIS and CNDDB databases include 25 occurrences (dating from 1927 to 1997). Twenty-three of those mapped locations occur at Vail Lake. One historic location (dated 1927) is mapped in Aguanga but the location is considered suspect due to a very low estimate of precision. The other disjunct location is mapped in Temecula; this location should be verified. The mapping data does not include a lone individual in the vicinity of the City of Riverside (CNDDB 1998). Published literature regarding specialist pollinators, seed dispersal vectors, and germination regimes is not available for this species. Habitat and Habitat Associations Nevin's barberry is found in coarse soils and rocky slopes in chaparral and gravelly wash margins in alluvial scrub (Niehaus 1977; Boyd 1987). Biogeography Nevin's barberry is endemic to southwestern cismontane southern California. It occurs in restricted localized populations from the interior foothills of the San Gabriel Mountains of Los Angeles County and San Bernardino County southeast to near the foothills of the Agua Tibia Mountains of southwestern Riverside County, from 300 and 659 meters in elevation (CNDDB; Munz 1974; Williams 1993). Scattered naturalized populations have been established outside this range (CNDDB 2000; Reiser 1996). Range Nevin's barberry is known in only four areas in Riverside County: Vail Lake, Riverside, Temecula and Aguanga. The largest population complex is known from the vicinity of the Vail Lake/Oak Mountain area along the north slope of the Agua Tibia Mountains (Boyd, Arnseth, and Ross 1991, Boyd and Banks 1995). The Vail Lake complex includes about 16 populations, the majority with five or fewer individuals for a cumulative total of about 200 individuals (CNDDB 1998, U.S. Fish and Wildlife Service 1998). This population complex is the largest known concentration of B. nevinii in the United States (U.S. Fish and Wildlife Service 1998). Most of these populations are on private lands, although a few individuals occur on Bureau of Land Management lands north of Vail Lake and in the Cleveland National Forest southeast of Vail Lake. A lone individual has been reported from a rocky outcrop in a residential area in the city of Riverside (U.S. Fish and Wildlife Service 1998). The Aguanga location is historic (dated 1927) and the mapped location is considered suspect due to a very low estimate of precision. The other disjunct location is mapped in Temecula; the Temecula location should be verified (CNDDB). Key Populations in Planning Area The key population of Nevin's barberry is located in the vicinity of Vail Lake. Biology Genetics: The genus Berberis includes two distinct subgenera: Mahonia and Berberis. Mahonia is recognized by some authors (e.g., Abrams 1934) as a separate genus. The subgenera Berberis and Mahonia are separated based on characters such as spineless/spiny stems, compound/simple leaves and susceptibility to black stem-rust of wheat (Puccinia graminis). Nevin's barberry is traditionally included in the subgenus Mahonia. Mahonia, although recognized in horticultural works as a distinct genus, is seldom recognized by botanists (Whittemore 1997). Reproduction: The racemes of yellow flowers bloom from March through April (U.S. Fish and Wildlife Service 1998). Seed production for Nevin's barberry is sporadic and fertility has been observed to be low (Boyd 1987). In cultivation studies, the reproductive success rate is observed to be low (Mistretta 1989). Nevin's barberry is able to stump sprout following a wildfire (U.S. Fish and Wildlife Service 1998) but vegetative propagation has not been successful in cultivation (Mistretta 1989). Dispersal: The juicy berries are yellow to red (Munz 1974; Whittemore 1997; U.S. Fish and Wildlife Service 1998). The seeds may be dispersed by animals: various birds have been observed eating the juicy berries (Wolf 1940). Threats Nevin's barberry is threatened by urban development, competition by annual grasses, off- road vehicle activity, emergency flood control activities (vegetation stripping), alteration of natural fire regime, fire fighting and control activities (U.S. Fish and Wildlife Service 1998). Special Biological Considerations As with chaparral species in general, fire frequency is an important factor to species persistence. Infrequent burns with the accompanying buildup of high fuel loads in chaparral communities results in unnaturally hot fires that may kill plants and destroy the seed banks of some species. A too frequent occurrence of fires can burn young or resprouting shrubs before they become reproductively mature, thus depleting or exhausting the seed bank (Zedler, Gautier, and McMaster 1983). Nevin's barberry is a stump-sprouter after wildfires but the effects of an altered fire regime on this species are unknown (U.S. Fish and Wildlife Service 1998). Literature Cited Boyd, S.D. 1987. Habitat Parameters of Mahonia nevinii (Gray) Fedde (Berberidaceae). Technical Report No. 3. Claremont, CA: Rancho Santa Ana Botanic Garden. 79 pp. Boyd, S.D., L.E. Arnseth, and T.S. Ross. 1989. Botanical Assessment of Bedford Properties Holdings Surrounding Vail Lake, Pauba Valley, Western Riverside County, California (Technical Appendix A). In Nelson, S.G., Boyd, S.D., Arnseth, L.E., and Ross, T.S. Biological Assessment of Bedford Properties Holdings Surrounding Vail Lake, Pauba Valley, Western Riverside County, California. Unpublished report submitted to Riverside County Board of Supervisors and Riverside County Planning Department, Riverside California. Boyd, S.D. and D.L. Banks. 1995. A Botanical Assessment of the Agua Tibia Wilderness Area, Cleveland National Forest. Rancho Santa Ana Botanic Garden, Claremont, California. 78 pp. Mistretta, O. 1989. Species Management Guide for Mahonia nevinii (Gray) Fedde. Technical Report No. 4. Rancho Santa Ana Botanic Garden, Claremont, California. 80 pp. Niehaus, T. 1977. Status Report on Berberis nevinii. Unpublished Report. California Native Plant Society, Berkeley. 4 pp. Reiser, C. 1996. Rare Plants of San Diego County, 1996 edition. Unpublished. Aquafir Press, San Diego, California. 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. 338 pp. U.S. Fish and Wildlife Service. 1998. Endangered and Threatened Wildlife and Plants; Endangered or Threatened Status for Three Plants from the Chaparral and Scrub of Southwestern California. Federal Register 63(17): 54956 - 54971. Williams, M.P. 1993. Berberis, pp. 362-363 in Hickman, J.C., editor, The Jepson Manual: Higher Plants of California. University of California Press, Berkeley. 1,400 pp. Whittemore, A.T. 1997. Berberis, pp. 276-286 in Flora of North America Editorial Committee, eds., Flora of North America, North of Mexico, Volume 3, Magnoliophyta: Magnoliidae and Hamamelidae, Oxford University Press, New York. 590 pp. Wolf, C. 1940. Mahonia nevinii, Nevin's Mahonia. Leaflets of Popular Information #35. Rancho Santa Ana Botanic Garden. Santa Ana Canyon, California. As cited in Mistretta 1989. Zedler, P.H., C.R. Gautier, and G.S. McMaster. 1983. Vegetation Change in Response to Extreme events: The Effect of a Short Interval Between Fires in California Chaparral and Coastal Scrub. Ecology 64(4): 809-818.