3.3 Biological Resources 3.3 BIOLOGICAL RESOURCES 3.3.1 Existing Conditions Regional Overview The influences of climate, topography, and soils combine to determine the character of the biological environment of a region. Each of these factors varies greatly throughout San Diego, resulting in a diversity of vegetation communities which include coastal wetlands, grasslands, vernal pools, sage scrub, chaparrals, riparian woodlands, oak woodlands, coniferous forests, and creosote bush scrub. The San Diego region contains habitats and species that are considered to be sensitive by state and federal agencies, affected local jurisdictions and conservation organizations. The San Diego region has been identified as a major “hot spot” for biodiversity and species endangerments. Many unique and endangered species are found only in this region. Sensitive Resources The biological resources documented in this section were determined through an extensive review of the most current biological literature and Geographical Information Systems (GIS) data available for the City of San Diego. Vegetation communities and sensitive plant and animal species were identified based on the regional vegetation map, prepared by the City of San Diego, which is incorporated into the Multiple Species Conservation Program (MSCP) database San Diego GIS 1995 (SANGIS 1995). General flora and fauna species were determined based on the identified vegetation communities and the species that typically occur in these habitats (Figure 3.3-1). Biological Habitats and Communities A host of upland and wetland vegetation communities, defined according to the current Holland Code (HC) classification system (Holland 1986) and San Diego County terrestrial vegetation community descriptions (Oberbauer 1996), occur within the City of San Diego. For ease of discussion, some of the habitats have been grouped under broader habitat categories that are specifically addressed within the City Land Development Manual – Biology Guidelines (as amended July, 2002). These categories are organized by habitat tiers, as specified in the City’s Biology Guidelines, rather than natural habitat groupings (Table 3.3-1). Draft General Plan City of San Diego Final PEIR 3.3-1 September 2007 3.3 Biological Resources Table 3.3-1 Habitat Types within the City of San Diego UPLAND HABITATS Habitat Type Tier I: Southern Foredunes (rare uplands) Torrey Pines Forest Coastal Bluff Scrub Maritime Succulent Scrub Maritime Chaparral Scrub Oak Chaparral Native Grassland Oak Woodland Tier II: Coastal Sage Scrub (CSS) (uncommon uplands) CSS/Chaparral Tier III A: Chaparral (common uplands) Mixed Chaparral Chamise Chaparral Tier III B: Valley and Foothill Grasslands (common uplands) Non-native Grasslands Tier IV: Urban/Developed (other uplands) Disturbed Agriculture Eucalyptus Woodland WETLAND HABITATS Coastal Salt Marsh Salt Panne/Mudflat Riparian Oak Riparian Forest Riparian Forest Riparian Woodland Riparian Scrub/Riparian Scrub in the Coastal Overlay Zone Riparian and Bottomland Habitat Freshwater Marsh Freshwater Seep Freshwater Marsh/Freshwater Marsh in the Coastal Overlay Zone Disturbed Wetland Disturbed Wetland Unvegetated Freshwater Non-vegetated Channel, Floodway, Lakeshore Fringe Unvegetated Habitat Freshwater Marine Habitats Unvegetated Habitat Estuarine Unvegetated Habitat Beach Unvegetated Habitat Marine Intertidal Unvegetated Habitat Marine Subtidal Unvegetated Habitat Shallow Bay Unvegetated Habitat Intermediate Bay Source: Merkel & Associates, 2003 Draft General Plan City of San Diego Final PEIR 3.3-2 September 2007 3.3 Biological Resources Upland Habitats Tier I Habitats – Rare Uplands Tier I habitats include the upland habitats that are considered to be rare within the City of San Diego. These habitats have suffered substantial historic losses on top of naturally narrow distribution patterns, such as in the case of southern foredunes and Torrey pine woodlands. Tier I habitats were once common, as was the case for native grasslands, but other historic land conversion has resulted in precipitous declines that threaten the continued persistence of the habitats in the region. Southern Foredunes Southern foredunes (HC 21230) are a relatively uncommon constituent of today’s City beaches, but two hundred years ago were widely dispersed at the upper edge of the region’s oceanic high tides where they occupied hummocky areas of sand and the interstitial swales. The most common components of this vestigial vegetation are two species of abronia (Abronia maritima, A. umbellata), beach evening primrose (Camissonia cheiranthifolia), and beach ambrosia (Ambrosia bipinnatisecta). Torrey Pines Forest This remnant coniferous forest habitat (HC 83140) is now restricted in the mainland United States to several stands of Torrey pines at Torrey Pines State Park and around the city of Del Mar. It appears to rely on moisture supplied by frequent fogs and is strongly correlated with marine sandstone substrate. Coastal Bluff Scrub Few native plants can survive on the erosive slopes of San Diego’s coastal bluffs. Typically, this scrub (HC 31000) is comprised of plants that are adapted to a regime of fogs, and a generally wetter environment that is found a short distance inland, including some succulent-leaved plants such as Coreopsis spp. and coast pincushion flower (Chaenactis glabriuscula var. orcuttiana). Other plants are adapted to salt tolerant conditions and include species of saltbush (Atriplex spp.) and pineapple weed (Chamomilla suaveolens). This vegetation community is declining as the bluffs erode, where very disturbed weedy mesa vegetation is replacing the existing coastal bluff scrub. Maritime Succulent Scrub This scrub (HC 32400) is largely associated with the flora in northern Baja California. It occurs in the United States primarily in the extreme southwestern portions of San Diego County near the Mexican border. Dominant shrubs here typically include jojoba (Simmondsia chinensis) and flat-top buckwheat (Eriogonum fasciculatum). This phase of sage scrub also includes several desert elements such as four-wing saltbush (Atriplex canescens), waterjacket (Lycium andersonii), and sometimes very unusual species for western San Diego County such as smooth- stemmed fagonia (Fagonia laevis) and desert filaree (Erodium texanum). Maritime Chaparral This phase of coastal chaparral, southern maritime chaparral (HC 37C30) located on north-facing slopes is a vestigial remnant of the wetter and cooler Pleistocene. It generally is restricted to sandstone substrates and usually includes at least one of the following shrub species: Del Mar Draft General Plan City of San Diego Final PEIR 3.3-3 September 2007 3.3 Biological Resources manzanita (Arctostaphylos glandulosa ssp. crassifolia), Nuttall’s scrub oak (Quercus dumosa), and/or coast white lilac (Ceanothus verrucosus). Scrub Oak Chaparral Scrub oak chaparral (HC 37900) is a dense, evergreen chaparral reaching up to 20 feet tall. The vegetation is dominated by Nuttall’s scrub oak (Quercus dumosa), with inclusions of interior mountain-mahogany (Cercocarpus betuloides var. betuloides) and a substantial accumulation of leaf litter. This chaparral type typically occurs in more mesic (moist) locations, and often at a slightly higher elevation, than other chaparral types, thus enabling the vegetation to recover more quickly from fire. Native Grassland Valley needlegrass grassland (HC 42110) typically supports extensive stands of purple needlegrass (Nasella pulchra) as the indicator species for its presence. A limited association of herbaceous perennials and annuals are often found growing among the clumps of needlegrass – including several rare species. Oak Woodland Oak woodlands within the City of San Diego are dominated by coast live oak woodlands (HC 71160). These habitats are evergreen woodlands primarily dominated by coast live oak (Quercus agrifolia); with a relatively open and low-growing understory that supports perennial grasslands, annuals, and herbaceous perennials, as well as a mix of shrubs and sometimes-dense thickets of western poison oak. Additional characteristic flora species include California blackberry, San Diego sedge (Carex spissa), California coffeeberry (Rhamnus californica), California rose (Rosa californica), nodding needlegrass (Nassella cernua) and large clarkia (Clarkia purpurea). Dense coast live oak woodland (HC 71162) is a dense phase of oak woodland characterized by a contiguous canopy of coast live oak with few additional tree or shrub components. The understory may be less diverse than that associated with a less mature phase of oak woodland. Tier II Habitats – Uncommon Uplands Coastal Sage Scrub The most common native vegetation type remaining within the boundaries of the City of San Diego (MSCP Table of Vegetation Communities 1998) is Diegan coastal sage scrub (HC 32500). This phase of sage scrub is a low-lying, relatively open scrub with desert affinities, and is comprised of soft-woody, drought deciduous species that provide the majority of the vegetative cover. Characteristic flora species include California sagebrush (Artemisia californica), coyote brush (Baccharis pilularis), California encelia (Encelia californica), goldenbush (Isocoma menziesii), laurel sumac (Malosma laurina), foothill needlegrass (Nassella lepida), lemonadeberry (Rhus integrifolia), black sage (Salvia mellifera), San Diego monkeyflower (Mimulus aurantiacus), and California brickellbush (Brickellia californica). A disturbed form of coastal sage scrub is broom baccharis