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5.7 Biological Resources

Solano, Stanislaus, Tehama, and Ventura Counties were determined to be critical habitat for
this species. Three other vernal pool crustacean species had Critical Habitat designated
within the same document: longhorn fairy shrimp (Branchinecta longiantenna), vernal pool
fairy shrimp, and vernal pool tadpole shrimp (Lepidurus packardi). Although there are no
records of this species within the vicinity of the site, survey data are limited. A habitat
assessment conducted by Glenn Lukos Associates indicated that suitable conditions for this
species may occur on the Project site (GLA 2005b). This species was not observed during
protocol dry and wet season surveys of two seasonal ponds in 2004–2005 (GLA 2005a). The
conservancy fairy shrimp is not expected to occur on the Project site due to negative results
of focused surveys.

Vernal Pool Fairy Shrimp

The vernal pool fairy shrimp is a federally listed Threatened Species. It occupies a variety of
different vernal pool habitats from small, clear, sandstone rock pools to large, turbid,
alkaline, grassland valley pools. The vernal pool fairy shrimp requires water temperatures
of 10 degrees Celsius (°C, 50 degrees Fahrenheit [°F]) or less for cysts to hatch, and time to
sexual maturity ranges from an absolute minimum of 18 days at 20°C (68°F) to a more typical
41 days at 15°C (59°F). Longevity ranges from about 70 days to a maximum of 139 days
(Eriksen and Belk 1999). Although the species has been collected from large vernal pools,
including 1 exceeding 25 acres, it tends to occur in smaller pools. It is most frequently found
in pools measuring less than 0.05 acre (Impact Sciences 2003). These are most commonly
found in grass- or mud-bottomed swales, or basalt flow depression pools in unplowed
grasslands (USFWS 1994b). This species has been recorded from elevations as high as 5,600
feet above msl. The vernal pool fairy shrimp is known from three locations in Los Angeles
County: one near Via Princessa, one at Cruzan Mesa, and the third at nearby Plum Canyon in
the Santa Clarita area (Impact Sciences 2011; GLA 2005b).

A total of 597,821 acres in Jackson County, Oregon and Alameda, Amador, Butte, Contra
Costa, Fresno, Kings, Madera, Mariposa, Merced, Monterey, Napa, Placer, Sacramento,
San Benito, San Joaquin, San Luis Obispo, Santa Barbara, Shasta, Solano, Stanislaus, Tehama,
Tulare, Ventura, and Yuba Counties, California were determined to be Critical Habitat for this
species. A habitat assessment conducted by Glenn Lukos Associates indicated that suitable
conditions for this species may occur on the Project site (GLA 2005b); however, it was not
observed during protocol dry and wet season surveys of two seasonal ponds in 2004–2005
(GLA 2005a). Based on the absence of this species from the two ponds during protocol
surveys, the lack of reported occurrences in the site vicinity, and the location of the Project
site outside the Critical Habitat designation for this species, the vernal pool fairy shrimp is
not expected to occur on the Project site.

Amphibians and Reptiles

Arroyo Toad

The arroyo toad is a federally listed Endangered Species and a California Species of Special
Concern. This species historically occurred from San Luis Obispo to San Diego Counties along
most major rivers. Most of the remaining populations occur in the national forests. The
nearest recorded observation location is Piru Creek in the Los Padres National Forest (CDFW

R:\Projects\PAS\CEN\000306\Draft EIR\5.7 Bio_051117.docx 5.7-107 Centennial Project
Draft EIR