RES 231363 - Laserfiche WebLink

AUGUSTIN BERNAL MOUNTAIN BIKE TRAIL PROJECT DRAFT INITIAL STUDY 12956 DUDEK 35 April 2022 backwaters within streams, ponds, marshes, springs, and artificial impoundments such as stock ponds. During the non-breeding season, they need moist areas in which to take refuge from the heat and predators, such as intermittent or ephemeral streams with dense riparian vegetation, overhanging banks, and rootwads; springs or spring boxes; rodent burrows; and damp leaf litter in riparian woodlands. (Ford et al. 2013) The USFWS designated 450,288 acres of critical habitat for California red-legged frog in 19 California counties on May 15, 2006 (71 FR 19243). Critical habitat for this species has been revised several times since 2006, with the most recent revision (and the one currently in effect) dated March 17, 2010 and comprising approximately 1,636,609 acres in 27 counties (75 FR 12816). Critical habitat designations include smaller discrete areas called primary constituent element (PCE), which describe aspects of physical or biological features on which the species is dependent. PCEs of designated California red-legged frog critical habitat are summarized as follows: 1. Aquatic Breeding Habitat: Standing bodies of fresh water (with salinities less than 4.5 ppt.), including natural and manmade (e.g., stock) ponds, slow-moving streams or pools within streams, and other ephemeral or permanent water bodies that typically become inundated during winter rains and hold water for a minimum of 20 weeks in all but the driest of years; 2. Aquatic Non-Breeding Habitat: Freshwater pond and stream habitats that may not hold water long enough for the species to complete its aquatic life cycle but which provide for shelter, foraging, predator avoidance, and aquatic dispersal of juvenile and adult California red-legged frogs. Other wetland habitats considered to meet these criteria include, but are not limited to: plunge pools within intermittent creeks, seeps, quiet backwaters within streams during high water flows, and springs of sufficient flow to provide mesic surface conditions during dry periods; 3. Upland Habitat: upland areas adjacent to or surrounding breeding and non-breeding aquatic and riparian habitat up to a distance of 1 mile in most cases (i.e., depending on surrounding landscape and dispersal barriers) including various vegetation types such as grassland, woodland, forest, wetland, or riparian areas that provide shelter, forage, and predator avoidance for the California red-legged frog; and, 4. Dispersal Habitat: Accessible upland or riparian habitat within and between occupied or previously occupied sites that are located within 1 mile of each other, and that support movement between such sites. The project site does not overlap with any designated critical habitat units for California red-legged frog. Subunit ALA-1B of the Alameda and Contra Costa Counties critical habitat unit is approximately 2.7 miles northwest of the site. California red-legged frog has low potential to occur on the project site during the rainy season (generally October to April). The closest known CNDDB occurrence is a 2016 observation of adults and metamorphs in a pond on Pleasanton Ridge approximately 1.1 mile to the northwest. Another pond visible on Google Earth aerial imagery approximately 0.9 mile northwest of the site also appears to be suitable for breeding. Individual red-legged frogs potentially breeding in these ponds could move through the project site when dispersing to or from these ponds to other breeding habitat on Pleasanton Ridge on rainy nights. The site does not contain any streams or ponds that provide aquatic breeding habitat, however, and the ephemeral drainages lack vegetation that remains moist year-round (e.g., seeps, riparian vegetation) and therefore do