Special-Status Plant Survey Report Special-Status Plant Survey Report 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 TABLE OF CONTENTS Section Page 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 LIST OF FIGURES Figure Page 1 Regional Context Map .................................................................................................................................4 2 Location Dominant Plant Communities on the Hidden Creeks Estates Project Site and Impact Area...................................................................................................................................................5 LIST OF TABLES Table Page 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 theHidden Creeks Project Site....................................................................7 Impact Sciences, Inc. i Hidden Creeks Project Site 860-001 June 2006 Special-Status Plant Survey Report 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), round- leaved 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 special- status 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 special- status 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 860-001 June 2006 Special-Status Plant Survey Report 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 860-001 June 2006 Kern County Los Angeles County LIFORN CA IA O ALIF RNIA 14 C 138 California Aqueduct LIFORN CA IA 138 INTERSTATE 5 LIFORN CA IA LIFORN 138 CA IA 18 LIFORN CA IA 138 LIFORN Los Angeles County CA IA 14 LIFORN CA IA Santa Clarita Ventura County 126 LIFORN CA IA LIFORN 126 Project CA IA Site 2 Porter LIFORN CA IA Ranch LIFORN CA IA LIFORN 118 Mission Hills CA IA 118 2 Granada Hills Chatsworth INTERSTATE LIFORN INTERSTATE CA IA 210 405 27 Sun Valley INTERSTATE US LIFORN Warner Center CA IA LIFORN CA IA US 5 LIFORN 101 CA IA 101 170 2 LIFORN CA IA 39 INTERSTATE Woodland Hills Encino 134 Sherman Oaks 210 US LIFORNI Pasadena CA A Calabasas 101 30 South IFORN Hollywood L CA IA INTERSTATE Pasadena US LIFORN CA IA LIFORNI San Bernardino County