SFPUC 2001 Alameda Watershed Management Plan

III. ENVIRONMENTAL SETTING AND IMPACTSE. NATURAL RESOURCESCallipe silverspot butterfly (Speyeria callippe callippe). This species is federally endangeredand occurs in coastal grasslands. Its larval foodplant is Viola pedunculata. Adults have beenobserved using various thistles (Cirsium spp.) and mint (Monardella spp.) for nectar. Oncewidespread throughout the Bay Area, this butterfly is now known only in San Bruno Mountain inSan Mateo County, Joaquin Miller and Redwood Regional Parks in Alameda County and thehills of southern Solano County (Federal Register, 1997; Arnold, 1981). Populations within theLivermore Valley are considered to be intermediate between two populations of silverspotbutterflies: one population restricted to the Bay Area, and the second, more common populationoccurs in central and southern California. Factors leading to the decline of this butterfly includeovercollecting, urban development, non-native plant invasion and competition and excessivelivestock grazing (Federal Register, December 5, 1997). Further studies would be required todetermine species presence and population size in the Watershed.Myrtle silverspot butterfly (Speyeria zerene myrtleae). This species is federally endangeredand occurs in coastal native grasslands where its larval foodplant, Viola pedunculata, is found.Potential habitat within the Watershed includes the few patches of native grassland and oaksavanna.California red-legged frog (Rana aurora draytonii). This species is federally threatened andprimarily inhabits ponds, but will also inhabit slow-moving streams or pools in intermittentstreams. Preferred ponds are usually permanent and at least 3 feet deep, with emergentvegetation (such as cattails) and shoreline cover (Stebbins, 1985). The range of this speciesextends from the western slope of the Cascade–Sierran mountain system, the North and SouthCoast Ranges, and the Transverse Range. This species is active year-long on the coast, but willaestivate (become dormant) from late summer to early winter inland (CDFG, 1988). Threats tothis species are habitat loss and introduction of non-native species. Sightings of California redleggedfrog are reported along Alameda Creek from studies conducted in 1993 (Leidy, 1993;DiDonato, 1997). Leidy reported California red-legged frogs in the faster moving areas ofAlameda Creek and along the upper reaches of most streams flowing into Calaveras Reservoir.Biologists with the EBRPD report this species above Little Yosemite on Alameda Creek.Bullfrogs were also reported from these areas, though in isolated pockets and limited numbers(Environmental Science Associates, 1999). California red-legged frogs were observed in 1997within approximately 3 miles south of the Sunol Valley along Alameda Creek (EnvironmentalScience Associates, 1999).Alameda whipsnake (Masticophis lateralis euryxanthus). This species is federally and statethreatened. The whipsnake prefers south, southwest and southeast facing slopes of open areas incoastal scrub and chaparral stands. A good rodent population is essential to provide retreatburrows. Spiny lizards, such as western fence lizards, are especially important to the diet of thisspecies. Urban development and associated impacts due to increased population densities,inappropriate grazing practices and alteration of suitable habitat from fire suppression are theprimary reasons for the decline in population numbers of this species. Suitable resident habitatand travel corridors occur for this species around both San Antonio and Calaveras Reservoirs.NOP 96.223E: Alameda Watershed Management Plan III.E-22 ESA / 930385January 2001