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4.7 BIOLOGICAL RESOURCES Mammals The most conspicuous native mammal on the site is the black-tailed deer (Odocoileus hemionus columbianus)which relies mainly on several brush species, including poison oak, for its main browse or woody plant food. In this area it is in partial competition with cattle which range freely throughout the riparian woodland and browse heavily on green brush species in the fall after all the green grass has dried. The black-tailed hare (Lepus californicus)was the most frequently observed native mammal on the site. On two occasions freshly killed specimens were found that had been shot. Random portions of the grassland, oak savanna, and seasonal wetland areas contain numerous signs (burrows, runways,etc.) of rodents such as the California meadow vole (Microtis californicus), Botta's pocket gopher (Thomomys bottae), and in sparsely vegetated areas, the California ground squirrel (Spermophilus beecheyi). With the exception of the latter, most of the small rodent signs were observed on grassland/woodland edge areas where heavy grazing and trampling by cattle had not occurred. It follows from this observation that if cattle were removed from the grassland community and a dense grass mat ground cover was allowed to form, rodent production on the site would dramatically increase and with it, a larger number of predator species. A strong rodent prey base forms the primary consumer link of the food chain upon which the hawk and owl species previously mentioned, plus mammalian carnivores such as coyote(Canis latrans),gray fox(Urocyon cinereoargenteus),badger(Taxidae taxus), and raccoon (Procyon lotor), depend. All of these species were observed either directly or indirectly (tracks,scat, etc.)during the course of the study. Perhaps the most interesting wild mammal observation made during the survey was that of a natal den of coyotes located at the southern edge of Brovelli Woods. An adult pair raised four pups at this location while apparently foraging on and adjacent to the project site. Endangered/Threatened Species and Habitat Plants None of the species reported by Muick, 1989,or those observed during the spring 1992 survey are listed as endangered or threatened by the California Department of Fish and Game or in the category lists 1 and 2 of the California Native Plant Society. This includes species observed in the vernal pools,a habitat which often contains threatened or endangered plants. 4.7-19