SR 06:242 - Laserfiche WebLink

1.0 INTRODUCTION This report presents the results of a special status plant survey conducted on the Austin property (Study Area) in Pleasanton, Alameda County, California (Figure 1). The purpose of this study is to identify the location and presence of potentially occurring sensitive plant species. Three focused special status plant surveys were conducted by WRA botanists within the Study Area that coincided with peak blooming periods of 30 potentially occurring special status species. One early-season and two late-season surveys were conducted on April 26, June 3, and July 30, 2005, respectively; these surveys did not locate any special status plant species. 1.1 Study Area Description The Study Area is situated along Old Foothill Road, approximately 1.75 miles west of downtown Pleasanton (Figure 1). The Study Area is bounded by Old Foothill Road to the east, a housing development to the south, and rural residential areas to the north and wes!. Current land use includes light cattle grazing and limited residential use. Land use of the surrounding area includes residential development and areas of open space with habitat characteristics similar to those olthe Study Area. The Study Area is located in the southeastern section of the United States Geologic Survey (USGS) Dublin quadrangle, directly across Old Foothill Road from the historic Alviso Adobe. The Study Area is approximately 80 acres of open, rolling hills and alternating drainages, situated on the toeslope of eastern Sunol Ridge. This area supports predominantly grassland with scattered oaks and sycamores, open oak woodland, and seasonal wetlands in swales that drain the southwest side of the property. Representative photographs of these habitats are provided in Appendix A. Most of the upland portion of the Study Area is moderately sloped. The average elevation of the Study Area ranges from 375 to 500 feet NGVD. 1.1.1 Vegetation The dominant vegetation communities throughout the Study Area consist of California Annual Grassland series, Mixed Oak Woodland series (Sawyer and Keeler-Wolf 1995), and seasonal emergent wetlands. Within the Mixed Oak Woodland series, the dominant tree species were coast live oak (Quercus agrifolia) and valley oak (Quercus lobata). The sparse shrub-dominated sub- canopy was comprised predominantly of poison oak (Toxicodendron diversilobum), manzanita (Arctostaphylos sp.), California buckwheat (Eriogonum fasciculatum), and bush monkeyflower (Mimulus aurantiacus). The herbaceous understory was characterized by grass species including slender wild oat (Avena barbata), blue wildrye (Elymus glaucus), melic grass (Melica imperfecta), and Mediterranean barley (Hordeum marinum ssp. gussoneanum), as well as lorb species such as California bedstraw (Galium califomica) and.common madia (Madia elegans). The California Annual Grassland series (Sawyer and Keeler-Wolf 1995) had a substantial native component limited to hill summits and shoulders. Native grass species included melic grass, blue wildrye, big squirreltail (Elymus multisetus), purple needlegrass (Nassella pulchra), and Calilornia fescue (Festuca califomica). Non-native annual grass species present included slender wild oat, false brome (Brachypodium distachyon), hedgehog dogtail (Cynosurus echinatus), little quaking grass (Briza minor), rattail fescue (Vulpia myuros), ripgut brome (Bromus diandrus), and nit grass (Gastridium ventricosum). 1