SFPUC 2001 Alameda Watershed Management Plan

III. ENVIRONMENTAL SETTING AND IMPACTSE. NATURAL RESOURCESCoast live oak riparian is found in canyon bottoms and the drier outer floodplains. Theunderstory for this habitat consists of poison oak, blackberry bushes, and snowberry in the wetterareas and poison oak and grasses in the drier areas. As with other riparian habitats, coast live oakriparian provides water, foraging, nesting, cover, and migration and dispersal corridors for a varietyof wildlife species. Common insect eaters and foliage gleaners include ash-throated flycatcher,plain titmouse, and dark-eyed junco. Bark gleaner species such as scrub jay, Steller’s jay, and acornwoodpecker feed on insects as well as acorns. California quail and brown towhee are the groundfoliage gleaners of this habitat. Red-shouldered hawks can be seen foraging on small mammals inthe adjacent grassland from perches in the coast live oak riparian forest. Cooper’s hawks and sharpshinnedhawks are often associated with this habitat and hunt small birds. Mammals such as graysquirrel forage and nest in the canopy of the trees, and long-tailed weasels hunt for shrews andmeadow voles on the ground. Larger mammals, such as mule deer use the wet understory of thiscommunity (such as poison oak and blackberry) for shelter and food from the berries. Amphibianslike the Pacific slender salamander, rough skinned newt, and ensatina can be found underneath thecover of fallen leaf litter and bark.White alder riparian forest occurs along the Arroyo Hondo and Alameda Creek, interspersedwith Sycamore alluvial woodland, and is often located at the bottom of a canyon stream course.This habitat consists of a narrow grove of trees with a sparse understory. It offers similar nestingand foraging resources for wildlife as willow riparian, due to the dense structure of the treecanopy (cover), moist environment for insects and foraging, and its location along streams.Sycamore alluvial woodland occurs in the bottoms of ravines and canyons. It is ofteninterspersed with cottonwood and oaks, as found along the east end of San Antonio Reservoir,the south end of Calaveras Reservoir, and along Alameda Creek. Wildlife species move in andout of this habitat throughout the year because of the presence of ephemeral streams.Amphibians, such as California red-legged frogs and foothill yellow-legged frogs, moveupstream when the water recedes; and reptiles, such as the Alameda whipsnake, come fromadjacent coastal scrub habitat and use the sycamore alluvial woodland as extended habitat forforaging and drinking. The large trees and thin canopy of the habitat provide perching surfacesfor foraging raptors, such as red-tailed hawks and black-shouldered kites. Mammals, such asstriped skunk and raccoon, forage underneath rocks in the creek bottom for insects andamphibians, such as western toad and Coast Range newt. Birds and mammals use the woodlandas a migration corridor.Coastal scrub occurs on shallow, rocky soils in areas with an average annual rainfall of12 inches. Coastal scrub habitat contains species such as California quail, mourning dove, andrufous-sided towhee that are attracted to the edges of adjacent grasslands, oak woodland, orchaparral for foraging and nesting. Alameda whipsnakes utilize south, southeast and southwestfacing slopes of open stands of coastal scrub. The sandy soils often associated with coastal scrubhabitat provide ideal habitat for burrowing reptiles such as western fence lizards. Avian speciesthat use the canopy of the scrub for catching insects include Pacific slope flycatcher, Wilson’swarbler, and wrentit. Besides insects, flowering scrub vegetation (e.g., Ceanothus or deerbrush)attracts nectar drinkers such as Anna’s hummingbird. Cooper’s hawks hunt these smaller birdsNOP 96.223E: Alameda Watershed Management Plan III.E-13 ESA / 930385January 2001