ARCHIVED REPORTS_1991_1 - Laserfiche WebLink

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BIOLOGICAL SEITING Vegetation and Wildlife Associations Annual Grassland)Urban. The predominant vegetation community present on open space within the project site is a composite of Annual Grassland and Urban habitat. Open space within the project site has been routinely disced to keep the field free of weeds (Crump pens. comm.) and is characterized primarily by bare dirt. Non-native plants such as common horehound and yellow starthistle and native plants such as wild radish share space along the fence rows surrounding open areas. A small valley oak (six inch diameter at breast height) is located near the center of the project site's largest parcel of open space. Few wildlife species were observed on the project site. California ground squirrel burrows are located along the north fence row below a row of English walnut trees, and the open dirt field contains extensive networks of Botta's pocket gopher and broad-footed mole tailings. These fossorial mammals are potential prey items for hawks and snakes. Only a few urban-tolerant birds such as American crows and white-crowned sparrows were observed foraging in this field. The open space on the subject parcel is located immediately adjacent to an urban park setting set between the proposed project site and the Mokelumne River, which lies approximately 100 feet north of the proposed expansion area. This park setting is characterized by mowed lawns on rolling hills landscaped with non-native trees such as weeping willows and native California trees such as interior live oaks and California redwoods. Numerous bird species, including western bluebird, scrub jay, cedar waxwing and northern flicker, were observed in this setting. A sharp-shinned hawk was discovered hunting small birds in the trees bordering the project site. Broad-footed mole tailings are common on the lawns of the parkway. Lakustrine. A horseshoe-shaped pond in the parkway provides Lakustrine habitat within the study area. Small stands of cattails line the shore of this groundwater-fed pond, providing breeding opportunities for marsh wrens and American coots. Mallards and black phoebes were observed foraging on and above the water, and the pond is stocked with black bass (Crump pers. comm.), providing potential prey for fish-eating birds. Valley-Foothill Riparian. The Mokelumne River supports a narrow corridor of Valley- Foothill Riparian habitat. Fremont cottonwoods, valley oaks, and California sycamores form the canopy of this community. The midstory and understory are composed of small tree willows and white alder, as well as shrubs such as Himalaya blackberry brambles and poison oak. Most of this riparian habitat is contained between the river levees. Riparian habitats are the most productive and diverse habitats in California. The riparian woodland along the river is valuable to birds because the complex three-dimensional habitat provides food, water, shelter, roosting and nesting opportunities for many avian species. Riparian woodland is also important to non-avian fauna. Predatory mammals such as gray foxes hunt and migrate along the riverine corridor, and omnivorous mammals such as opossums and 5