For the Hidden Creeks Project Site, City of Los Angeles, Los Angeles County, California Prepared for: First American Communities 370 N. Westlake Boulevard, #130 Thousand Oaks, California 91362 Prepared by: Impact Sciences, Inc. 803 Camarillo Springs Road, Suite A Camarillo, California 93012 (805) 437-1900 June 2007
Section TABLE OF CONTENTS 1.0 SUMMARY...2 2.0 INTRODUCTION...2 2.1 Project Description...2 2.2 Purpose...2 3.0 ENVIRONMENTAL SETTING...2 3.1 General Site Characteristics...2 3.2 Plant Communities...3 4.0 SURVEY METHODOLOGY...13 4.1 Database Search...13 4.2 Presence/Absence Special-Status Plant Surveys...13 5.0 RESULTS...14 5.1 Database Search Results for Special-Status Plant Species...14 5.2 Presence/Absence Plant Survey Results...14 6.0 CONCLUSION...14 7.0 REFERENCES...15 Page Figure LIST OF FIGURES Page 1 Regional Context Map...4 2 Location Dominant Plant Communities on the Hidden Creeks Estates Project Site and Impact Area...5 Table LIST OF TABLES 1 Special-Status Plant Species with Potential to Occur on the Hidden Creeks Project Site Based on CNDDB and CNPS Database Search Results...6 2 Plant Species Observed on the Hidden Creeks Project Site...7 Page Impact Sciences, Inc. i Hidden Creeks Project Site
1.0 SUMMARY Focused surveys for special-status plant species were conducted on the Hidden Creeks project site. Suitable habitat exists on the site for the following ten special-status plant species known to occur in the area: Greata s aster (Aster greatae), Braunton s milk-vetch (Astralagus brauntonii), Nevin s barberry (Berberis nevinii), slender mariposa lily (Calochortus clavatus var. gracilis), Plummer s mariposa lily (Calochortus plummerae), San Fernando valley spineflower (Chorizanthe parryi var. fernandina), roundleaved filaree (Erodium macrophyllum), Los Angeles sunflower (Helianthus nuttallii ssp. parishii), Davidson s bush mallow (Malacothamnus davidsonii), and chaparral nolina (Nolina cismontana). These plant species were not observed on the site during the focused surveys; nor were any other specialstatus plant species. 2.0 INTRODUCTION 2.1 Project Description The Hidden Creeks Estates development is proposed as a gated community with 183 single-family residential lots and 5 residential equestrian lots, associated roadways and infrastructure, a 17-acre public park, and a new equestrian boarding facility. The majority of the residential lots will be clustered on a graded, centralized plateau currently used for ongoing filming operations and grazing. 2.2 Purpose The purpose of this report is to describe the findings of focused plant surveys that were conducted at the Hidden Creeks project site. Focused surveys were conducted to determine whether any specialstatus plant species are present on the site that may pose development constraints to the proposed project. Special-status plants include those that are state- or federally-listed as Rare, Threatened, or Endangered, proposed for state or federal listing as Threatened or Endangered, are federal Candidate species for listing, or are state and/or federal Species of Concern. In addition, plants included on Lists 1A, 1B, 2, 3, or 4 of the California Native Plant Society (CNPS) are also considered special-status. 3.0 ENVIRONMENTAL SETTING 3.1 General Site Characteristics The project site is located within the southern reaches of the Santa Susana Mountains, near the western edge of Los Angeles County. Open space borders the site immediately to the north, south, Impact Sciences, Inc. 2 Hidden Creeks Project Site
east, and west. Beyond the open space to the south is Highway 118. Existing uses within the project site boundaries consist of equestrian-related facilities located in the southeastern part of the property, movie and television production facilities located in the central-eastern part of the property, and cattle ranching facilities and associated access roads located throughout the property. The regional location of the site is shown in Figure 1, Regional Context Map. Elevations within the Hidden Creeks Estates property ranges from approximately 1,350 feet above mean sea level in the southernmost extent of the property, at the confluence of Browns Canyon Wash and Mormon Canyon, to 2,145 feet in the northernmost extent. Topography on the site ranges from rolling hills with gentle slopes to steep hillsides and highly eroded streambanks. 3.2 Plant Communities There were 15 primary vegetation communities (CDFG, 2003) or land uses observed on the project site and/or in the Mason Avenue extension impact area. These include: Non-Native Grassland, Mixed Sage Scrub, Coast Live Oak Woodland, Disturbed, Coastal Sage Chaparral Scrub, California Sagebrush Scrub, Chamise Chaparral, Mixed Coast Live Oak-Willow Riparian Woodland, Tamarisk Scrub, California Walnut Woodland, Mixed California Black Walnut-Coast Live Oak Woodland, Mulefat Scrub, Mixed Willow Riparian Woodland, Bulrush-Cattail Wetland, and Mulefat Scrub-Non- Native Grassland (Figure 2, Location Dominant Plant Communities on the Hidden Creeks Estates Project Site and Impact Area.). Several of these plant communities could provide habitat for several special-status plants known to occur in the region of the site (Table 1, Special-Status Plant Species With Potential to Occur on the Hidden Creeks Project Site Based on CNDDB and CNPS Database Search Results). In addition, two plant communities, the Mixed Willow Riparian Woodland and the California Walnut Woodland, are considered sensitive natural communities by the CDFG, requiring mitigation for any acreage impacted. A complete list of species used to identify the various habitats and communities of the property is included in this report (Table 2, Plant Species Observed on the Hidden Creeks Project Site). 3.2.1 Non-Native Grassland (142.92Acres) The majority of vegetation observed on the site consisted of the Non-Native Grassland community, dominated by exotic annual grass such as wild oats (Avena fatua), foxtail barley (Hordeum murinum), and ripgut brome (Bromus diandrus). This community had a number of annual herb species as well, as plants such as black mustard (Brassica nigra), storks-bill filaree (Erodium cicutarium), and devil s lettuce (Amsinckia intermedia) were present. Non-Native Grassland occurs in the central portion of the site, and is most likely a result of the active grazing on site. Impact Sciences, Inc. 3 Hidden Creeks Project Site
138 14 Kern County Los Angeles County California Aqueduct 138 5 138 18 126 126 Santa Clarita 14 Project Site 2 138 US 101 23 118 Malibu P a c i f Calabasas Los Angeles County Ventura County 1 i c O Chatsworth 27 Warner Center Woodland Hills 27 Porter Ranch Mission Hills 118 Granada Hills c e a US 101 Encino n 405 Sherman Oaks Santa Monica 1 Sun Valley 170 101 Hollywood 2 Beverly Hills US Culver City 90 405 Inglewood 107 Rancho Palos Verdes 5 134 10 Gardena Torrance 1 213 San Pedro 110 110 210 5 Huntington Park 105 Compton 91 42 2 Carson Los Angeles Terminal Island South Pasadena 710 Downey Paramount 19 Lakewood 405 47 Long Beach Pasadena 10 Monterey Park Montbello 1 605 605 El Monte Whittier 72 Santa Fe Springs 5 2 Cerritos 210 La Mirada 39 405 60 90 39 10 57 71 30 US 66 Los Angeles County San Bernardino County 60 12 6 0 12 n APPROXIMATE SCALE IN MILES SOURCE: Impact Sciences, Inc. November 2006 FIGURE 1 Regional Context Map 860-001 03/07
Legend: Grading Limit Line Coastal Sage Chaparral Scrub Mixed Coast Live Oak-Willow Riparian Woodland California Walnut Woodland Disturbed Tamarisk Scrub California Sagebrush Scrub Mixed Sage Scrub Bulrush-Cattail Wetland Chamise Chaparral Mulefat Scrub Mixed Willow Riparian Woodland Mixed California Walnut-Coast Live Oak Woodland Mulefat Scrub/Non-Native Grassland Project Boundary Coast Live Oak Woodland Non-Native Grassland Off-Site Impact Area Boundary 500 250 n 0 500 APPROXIMATE SCALE IN FEET SOURCE: Impact Sciences, Inc. June 2007 FIGURE 2 Location Dominant Plant Communities on the Hidden Creeks Estates Project Site and Mason Avenue Extension Area 860-01 06/07
Table 1 Special-Status Plant Species with Potential to Occur on the Hidden Creeks Project Site Based on CNDDB and CNPS Database Search Results Common Name and Status Scientific Name Federal State CNPS Habitat Requirements Greata s aster Aster greatae Braunton s milk-vetch Astragalus brauntonii Nevin s barberry Berberis nevinii Slender mariposa lily Calochortus clavatus var. gracilis Plummer s mariposa lily Calochortus plummerae San Fernando Valley spineflower Chorizanthe parryi var. fernandina Round-leaved filaree Erodium macrophyllum -- -- 1B.3 Moist/dry places in canyons; associated with chaparral, oak woodland, between approximately 2000-4000 feet mean sea level (msl). FE -- 1B.1 Occurs in chaparral, coastal scrub, native and nonnative grasslands, recent burns, or disturbed areas. Found on stiff gravelly soils overlying granite and limestone; below 1500 feet msl. FE SE 1B.2 Steep, north-facing slopes or low-grade sandy washes in chaparral, cismontane woodland, coastal scrub, or riparian scrub; between approximately 950 5,170 feet msl. -- -- 1B.2 Shaded foothill canyons, often in association with chaparral, coastal scrub, and grassy slopes in between habitats: below 2500 feet msl. -- -- 1B.2 Rocky and sandy sites, usually of granitic or alluvial material, within coastal scrub, chaparral, native and non-native grasslands, and forests and woodlands; between approximately 295 5,280 feet msl. FC SE 1B.1 Sandy soils within coastal scrub; between approximately 1,000 3,600 feet msl. -- -- 2.1 Occurs in cismontane woodland or foothill and valley grassland habitats on clay soils; below 3600 feet msl. Potential for Occurrence and Survey Results Suitable chaparral, oak woodland could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, coastal scrub, grasslands could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, coastal scrub could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, coastal scrub, grasslands could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, coastal scrub, grasslands could provide potential habitat. However, this species was not observed during focus surveys. Suitable soils and coastal scrub could provide potential habitat. However, this species was not observed during focus surveys. Suitable grasslands could provide potential habitat. However, this species was not observed during focus surveys. Impact Sciences, Inc. 6 Hidden Creeks Project Site
Common Name and Status Scientific Name Federal State CNPS Habitat Requirements Los Angeles sunflower Helianthus nuttallii ssp. parishii Davidson s bush mallow Malacothamnus davidsonii Chaparral nolina Nolina cismontana -- -- 1A Wet marshes, meadows in chaparral; between approximately 1000 1500 feet msl. -- -- 1B.2 Sandy washes within coastal scrub, riparian woodland, and chaparral; between approximately 590 2,805 feet msl. -- -- 1B.2 Occurs in chaparral and coastal scrub habitats on sandstone, shale, and gabbro substrates. Potential for Occurrence and Survey Results Suitable wetland in chaparral could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, riparian woodland, coastal scrub, could provide potential habitat. However, this species was not observed during focus surveys. Suitable chaparral, coastal scrub, could provide potential habitat. However, this species was not observed during focus surveys. STATUS KEY: Federal FE = Federally Endangered FC = Federal Species of Concern State SE = State Endangered CNPS List 1B = plants Rare, Threatened, Endangered in California and elsewhere List 2 = plants Rare, Threatened, Or Endangered in California List 4 = plants of limited distribution.1 = seriously Endangered in California.2 = fairly Endangered in California.3 = not very Endangered in California Table 2 Plant Species Observed on the Hidden Creeks Project Site Scientific Name ANGIOSPERMS DICOTYLEDONS ANACARDIACEAE Common Name SUMAC-CASHEW FAMILY Native Species (Yes/No) Malosma laurina Laurel sumac Yes Rhus integrifolia Lemonadeberry Yes Schinus molle Peruvian pepper tree No Toxicodendron diversilobum Poison oak Yes ASCLEPIADACEAE MILKWEED FAMILY Asclepias fascicularis Narrow-leaved milkweed Yes ASTERACEAE SUNFLOWER FAMILY Achillea millefolium Yarrow Yes Ambrosia sp. Ragweed Yes Artemisia californica California sagebrush Yes Baccharis pilularis Coyote brush Yes Baccharis salicifolia Mulefat Yes Carduus pycnocephalus Italian thistle No Centaurea solstitialis Yellow star-thistle No Impact Sciences, Inc. 7 Hidden Creeks Project Site
Scientific Name Common Name Native Species (Yes/No) Chrysanthemum coronarium Crown daisy No Encelia californica California brittlebush Yes Eriophyllum confertiflorum Golden yarrow Yes Gnaphalium californica Cudweed Yes Hazardia squarrosa Goldenbush Yes Sonchus oleraceus Common sow thistle No BORAGINACEAE BORAGE FAMILY Amsinckia menziesii Common fiddleneck Yes Cryptantha sp. Cryptantha Yes BRASSICACEAE MUSTARD FAMILY Brassica nigra Black mustard No CAPRIFOLIACEAE HONEYSUCKLE FAMILY Sambucus mexicana Mexican elderberry Yes CONVOLVULACEAE MORNING-GLORY FAMILY Calystegia sp. Morning glory Yes CUCURBITACEAE GOURD FAMILY Marah macrocarpus Wild cucumber Yes EUPHORBIACEAE SPURGE FAMILY Chamaesyce albomarginata Rattlesnake weed Yes Eremocarpus setigerus Turkey mullein Yes FABACEAE LEGUME FAMILY Lotus scoparius Common deerweed Yes Melilotus albus White sweetclover No Vicia sativa Spring vetch No FAGACEAE OAK FAMILY Quercus agrifolia Coast live oak Yes GERANIACEAE GERANIUM FAMILY Erodium cicutarium Red-stemmed filaree No HYDROPHYLLACEAE WATERLEAF FAMILY Eriodictyon crassifolium Thickleaf yerba santa Yes Phacelia cicutaria Caterpillar phacelia Yes Pholistoma membranaceum White fiesta flower Yes JUGLANDACEAE WALNUT FAMILY Juglans californica var. californica Southern California black walnut Yes LAMIACEAE MINT FAMILY Marrubium vulgare Horehound No Salvia apiana White sage Yes Salvia leucophylla Purple sage Yes Salvia mellifera Black sage Yes NYCTAGINACEAE FOUR O CLOCK FAMILY Mirabilis californica Wishbone Bush Yes ONAGRACEAE EVENING PRIMROSE FAMILY Clarkia purpurea ssp. quadrivulnera Winecup fairyfan Yes POLEMONIACEAE PHLOX FAMILY Leptodactylon californicum Prickly phlox Yes POLYGONACEAE BUCKWHEAT FAMILY Eriogonum fasciculatum var. fasciculatum California buckwheat Yes Rumex crispus Curly dock No Impact Sciences, Inc. 8 Hidden Creeks Project Site
Scientific Name PORTULACACEAE Common Name PURSLANE FAMILY Native Species (Yes/No) Claytonia perfoliata Miner s lettuce Yes PRIMULACEAE PRIMROSE FAMILY Anagallis arvensis Scarlet pimpernel No RHAMNACEAE CEANOTHUS Ceanothus crassifolius Hoary leaved ceanothus Yes ROSACEAE ROSE FAMILY Adenostemma fasciculatum Chamise Yes Heteromeles arbutifolia Toyon Prunus ilicifolia ssp. ilicifolia Holly-leafed cherry Yes RUBIACEAE BEDSTRAW FAMILY Galium angustifolium Narrow-leaved bedstraw Yes SALICACEAE WILLOW FAMILY Salix exigua Narrow-leaved willow Yes Salix laevigata Red willow Yes Salix lasiolepis Arroyo willow Yes SCROPHULARACEAE FIGWORT FAMILY Castilleja exserta ssp. exserta Purple owl s clover Yes Mimulus aurantiacus Northern yellow bush monkey flower Yes SOLANACEAE NIGHTSHADE FAMILY Nicotiana glauca Tree tobacco No Solanum xanti Purple nightshade Yes TAMARICACEAE TAMARISK FAMILY Tamarix sp. Tamarisk No URTICACEAE NETTLE FAMILY Urtica dioica Stinging nettle Yes ANGIOSPERMS MONOCOTYLEDONS CYPERACEAE SEDGE FAMILY Cyperus eragrostis Umbrella sedge Yes IRIDACEAE IRIS FAMILY Sisyrinchium bellum Blue-eyed grass Yes JUNCACEAE RUSH FAMILY Juncus mexicanus Mexican rush Yes Juncus sp. Rush species Scirpus sp. Bulrush species LILIACEAE LILY FAMILY Bloomeria crocea Goldenstars Yes Dichelostemma capitatum ssp. capitatum Blue dicks Yes Yucca whipplei Our Lord's candle Yes Zigadenus fremontii Death camas lily Yes POACEAE GRASS FAMILY Avena fatua Wild oats No Bromus diandrus Ripgut brome No Bromus hordeaceus Soft brome No Bromus madritensis ssp. rubens Red brome No Hordeum murinum Foxtail barley No Leymus condensatus Giant wild-rye Yes Nassella pulchra Purple needlegrass Yes Impact Sciences, Inc. 9 Hidden Creeks Project Site
Scientific Name Common Name Native Species (Yes/No) Poa secunda ssp. secunda One-sided bluegrass Yes Polypogon monspeliensis Annual beard-grass No TYPHACEAE CATTAIL FAMILY Typha latifolia Broad-leafed cattail Yes 3.2.2 Mixed Sage Scrub (44.57 Acres) Mixed Sage Scrub occurs on a number of slope faces throughout the site. This vegetation type is dominated by a mix of sage species including purple sage (Salvia leucophylla), black sage (Salvia mellifera), and white sage (Salvia apiana). Other co-dominants include California sagebrush (Artemisia californica) and California buckwheat (Eriogonum fasciculatum). This generally forms a continuous canopy with relatively few plants species in the understory. 3.2.3 Coast Live Oak Woodland (40.81 Acres) The Coast Live Oak Woodland community in this case is very similar to the California Walnut Series, with coast live oak trees (Quercus agrifolia) approximately 20 40 feet tall dominating the landscape and intermittent grasses, annual herbs, and shrubs in between. Red brome (Bromus madritensis ssp. Rubens), ripgut brome, and wild oats are all found in association with this series. Poison oak (Toxicodendron diversilobum) was observed at high densities between trees, forming low-growing thickets of vegetation. Other species include coyotebrush (Baccharis pilularis), California sagebrush, as well as annual herbs, such as tocolote (Centaurea melitensis), devil s lettuce, and wild cucumber (Marah macrocarpus). 3.2.4 Disturbed (34.86 Acres) Parts of the site have been built on, plowed, or mowed, resulting in the Disturbed area. This land use type is made up mostly of exotic, invasive weeds but nonetheless does include some native species. The dominants are red brome, wild oats, black mustard, and wire lettuce (Stephanomeria birgata). In addition, herbaceous annuals such as devil s lettuce and turkey mullein (Eremocarpus setigerus) are present. 3.2.5 Coastal Sage Chaparral Scrub (25.84) Slopes on the site generally consist of Mixed Sage Scrub or Coastal Sage Chaparral Scrub. The Coastal Sage Chaparral Scrub community contains sages as dominants, including purple and black sage, in addition to chaparral species, such as laurel sumac (Malosma laurina), chamise (Adenostoma Impact Sciences, Inc. 10 Hidden Creeks Project Site
fasciculatum), and toyon (Heteromeles arbutifolia). canopy, allowing for little growth underneath. This community also has an almost continuous 3.2.6 Chamise Chaparral (13.52 Acres) Along the north, east, and west boundaries of the site are pockets of Chamise Chaparral consisting of very dense cover dominated by chamise measuring approximately 4 feet in height. Other chaparral shrubs are present, although in substantially lower densities. This includes species such as hoaryleaf ceanothus (Ceanothus crassifolius), California buckwheat, yerba santa (Eriodictyon crassifolium), and California sagebrush. Grasses and herbaceous annuals can also be found in the under story of the chaparral community, where the overlying shrubs are not too dense. 3.2.7 Tamarisk Scrub (3.97 Acres) Throughout the grassland area, as well as near the house structures toward the northwest corner of the site, are stands of tamarisk (Tamarix parviflora) that have been planted, probably as wind protection. This makes up the Tamarisk Scrub plant community, composed almost entirely of tamarisk, with a few exotic grasses (Bromus spp.) observed in the understory. 3.2.8 California Walnut Woodland (3.38 Acres) Several areas in the northern portion of the site are composed of the California Walnut Woodland community, with trees measuring approximately 10 20 feet in height. The southern California black walnut trees (Juglans californica var. californica) are interspersed with open ground between individuals, allowing for grasses and herbaceous annuals to grow between. The majority of these species were grasses such as red brome, ripgut brome, wild oats, and foxtail barley. The site had a few annual herbs as well, as species such as tocalote, devil s lettuce, and wild cucumber were observed. This community is considered a sensitive natural community by the CDFG. 3.2.9 Mixed California Walnut-Coast Live Oak Woodland (2.88 Acres) In the central area of the site there is a drainage containing vegetation that is a mix between two series, a community that shares features from both the California Walnut Woodland (described above as vegetation type 3.2.8) and Coast Live Oak Woodland (described above as vegetation type 3.2.3) communities. This vegetation has two dominant plants, the California walnut, and the coast live oak trees. The grasses, annual herbs, and shrubs associated with these two series are also found in the mixed series. Impact Sciences, Inc. 11 Hidden Creeks Project Site
3.2.10 California Sagebrush Scrub (1.54 Acres) There are a number of areas on site that can be characterized as California Sagebrush Scrub. This vegetation type contains medium-sized shrubs, dominated by California sagebrush. This vegetation type also contains relatively low concentrations of purple sage, deerweed (Lotus scoparius), and California buckwheat. This community is nearly continuous, which suppresses most growth underneath. 3.2.11 Mixed Coast Live Oak-Willow Riparian Woodland (1.49 Acres) In the southeast area of the site there is a drainage that contains vegetation that is a mix between two series. This community shares features from both the Mixed Willow Riparian Woodland (which is described below, as vegetation type 3.2.12) and Coast Live Oak Woodland (which is described above, as vegetation type 3.2.3) communities. This vegetation has two dominant tree species, the arroyo willow (Salix lasiolepis), and the coast live oak. The grasses, annual herbs, and shrubs associated with these two series are also found in the mixed series. 3.2.12 Mulefat Scrub (0.89 Acre) Occurring within Browns Canyon Wash, as well as several other small drainages, is a plant community that is classified as Mulefat Scrub. This vegetation type is made up almost entirely of mulefat (Baccharis salicifolia), with very few plants in the understory. Species that did occur, although in low frequencies, were stinging nettle (Urtica dioica) and curly dock (Rumex crispus). 3.2.13 Mixed Willow Riparian Woodland (0.86 Acre) On the eastern side of the site, along Mormon Creek, is an area dominated by arroyo, red (Salix laevigata), and narrow-leaved willow (Salix exigua) trees. These tree species compose a Mixed Willow Riparian Woodland. Associated with this riparian area are rushes (Juncus spp.), broad-leafed cattail (Typha latifolia), and annual beard-grass (Polypogon monospeliensis). This community is considered a sensitive natural community by the CDFG. 3.2.14 Bulrush-Cattail Wetland (0.33 Acre) Adjacent to the Mason Avenue extension grading area is an area that is often inundated with water, creating a wetland environment due to the presence of hydric soils, hydrophytic plant species, and the presence of water. Dominant species associated with this area are the broad-leafed cattail, bulrush (Scirpus sp.), rushes, and annual beard-grass. In addition, several arroyo willow trees were observed within this area. Impact Sciences, Inc. 12 Hidden Creeks Project Site
3.2.15 Mulefat Scrub-Non-Native Grassland (0.32 Acre) This community, located in the western portion of the site adjacent to Brown's Canyon wash, contains vegetation characteristic of two vegetation types, Mulefat Scrub (described above as vegetation type 3.2.12), and Non-Native Grassland (described above as vegetation type 3.2.1). The area contains more moisture than the adjacent non-native grassland communities, thereby facilitating the growth of mulefat shrubs 5 8 feet tall, and resulting in classification of this vegetation community as a wetland due to the presence of hydric soils, hydrophytic plant species, and the presence of water. Non-native grasses such as ripgut brome, foxtail barley, and annual beard-grass occur in the understory, in addition to hydrophytic species such as Mexican rush (Juncus mexicanus) and umbrella sedge (Cyperus eragrostis). This community has been heavily grazed by cattle and exhibits signs of extreme disturbance, including trampling and grazing. 4.0 SURVEY METHODOLOGY 4.1 Database Search A review of the California Natural Diversity Database (CNDDB, 2005) and CNPS database (CNPS, 2006) was performed prior to visiting the site to identify special-status plant species known to occur in the area. Both the CNDDB and the CNPS list historical and recently recorded occurrences of special-status plant species within an identified region. The databases searched included the U.S. Geological Survey (USGS) 7.5-minute Oat Mountain Quadrangle and the surrounding eight USGS Quadrangles. Our assessment of the potential for special-status plant species to occur on the project site is based on the proximity of the site to recorded occurrences, on-site vegetation and habitat characteristics, topography, elevation, soils, surrounding land uses, previous documentation of biological resources on site, and known habitat preferences and geographic ranges of special-status plant species known to occur in the region. The results of this assessment form the basis for the species listed in Table 1. 4.2 Presence/Absence Special-Status Plant Surveys To accurately determine whether or not special-status plants identified in Table 1 actually occur on the site, presence/absence surveys were conducted during the appropriate blooming periods for each plant species. The methodology used for performing focused surveys followed the California Department of Fish and Game s 2000 Guidelines For Assessing The Effects Of Proposed Projects on Rare, Threatened, and Endangered Plants and Plant Communities, and the CNPS 2001 Policy on Botanical Survey Guidelines of the California Native Plant Society (Guidelines). These Guidelines were utilized to implement the proper methods for performing plant surveys, considering the environmental impacts Impact Sciences, Inc. 13 Hidden Creeks Project Site
that may occur as a result of new development, and developing the type of mitigation necessary to reduce project-related impacts to special-status plants. Two qualified biologists performed the presence/absence surveys on March 13, 14 and May 10, 12, 2006. The biologists walked the extent of each plant community and habitat that was determined to be suitable for supporting the special-status plant species shown in Table 1. The entire site was walked with transects no more than 20 feet apart. 5.0 RESULTS 5.1 Database Search Results for Special-Status Plant Species Table 1 includes all special-status plant species identified as occurring in the project region based on a review of the CNDDB and CNPS databases and the results of focused surveys during the appropriate blooming periods for those with potential to occur on site. 5.2 Presence/Absence Plant Survey Results No special-status plants previously recorded in the project vicinity (Table 1) were observed on the site during the focused surveys which were conducted during the appropriate blooming periods. The common species observed on the Hidden Creeks project site are listed in Table 2. The vascular plant nomenclature used in Table 2 follows The Jepson Manual and the World Wide Web internet site: http://ucjeps.berkeley.edu/interchange.html. 6.0 CONCLUSION No special-status plant species were observed on site. Since the 2006 presence/absence plant survey was performed during the appropriate blooming period for all of the potentially occurring specialstatus plant species known to occur in the area, and because the extent of the site was traversed by foot in appropriate habitats for supporting special-status plant species; no special-status plant species are expected to occur on the project site. Two communities observed on site, the California Walnut Woodland and Mixed Willow Riparian Willow Woodland are considered sensitive natural communities by the CDFG. Sensitive natural communities are plant associations within California that are on the decline, considered rare or locally important, or support special-status plants and animals. These communities usually require 1:1 mitigation for any acreage impacted; however, mitigation is at the final discretion of the CDFG. Impact Sciences, Inc. 14 Hidden Creeks Project Site
7.0 REFERENCES California Department of Fish and Game. 2003. Wildlife and Habitat Data Analysis Branch. California Department of Fish and Game Natural Diversity Database: Commercial version (May 27, 2005). California Department of Fish and Game. September 2003. Wildlife and Habitat Data Analysis Branch. California Department of Fish and Game Natural Diversity Database. List of California Terrestrial Natural Communities Recognized by The California Natural Diversity Database. California Native Plant Society, Inventory of Rare and Endangered Vascular Plants of California. edition. [Online inventory] www.cnps.org/inventory. 6 th California Native Plant Society Rare Plant Advisory Committee, (December 1983, revised June 2001). Botanical Survey Guidelines of the California Native Plant Society. Faber, Phyllis M., Keeler-Wolf, Todd, Ornduff, Robert. 2003. Introduction to California Plant Life. University of California Press, Berkeley and Los Angeles. California. 341 pp. Hickman, James C. ed. 1993. The Jepson Manual. Angeles, California. 1400 pp. University of California Press, Berkeley and Los Holland, R.F. 1986. Preliminary Descriptions of the Terrestrial Natural Communities of California. California Department of Fish and Game Report. 156 pp. Sawyer, John O. and Keeler-Wolf, Todd. 1995. A Manual of California Vegetation. Plant Society. United Sates of America. 471 pp. California Native Jepson Online Interchange. 2005. University of California, Berkeley. http./ucjeps.berkeley.edu/ interchange.html. Impact Sciences, Inc. 15 Hidden Creeks Project Site