Loading...
HomeMy WebLinkAbout1992-09-01; City Council; 11875; Status Report on Habitat Management PlanCITQOF CARLSBAD — AGENt£)BILL AB#_ GM STATUS REPORT ON HABITAT MANAGEMENT PLAN CITY MGlOS^- o oo RECOMMENDED ACTION: That the City Council: (1) accept the Biological Resources and Habitat Analysis Report prepared by the biological consulting team; (2) authorize the City Manager to execute supplements to the existing agreements with Consultants Collaborative Inc. and A. D. Hinshaw Associates to provide for Phase III consultant services; and (3) direct staff to proceed with Phase III of the Work Program for the Habitat Management Plan. ITEM EXPLANATION Background State and federal wildlife agencies, conservation groups, local government, and the development industry are in agreement that the reactive, species-by-species and project-by-project approach used in the past to address wildlife habitat is not the most effective way to protect rare plants and animals from the threat of extinction, nor is it an efficient way to plan for development. All sides are now endorsing a proactive approach such as represented by Carlsbad's Habitat Management Plan (HMP). The proposed listing of the California Gnatcatcher has brought the issue to the forefront of land use planning in this region. If the California Gnatcatcher is listed as threatened or endangered, already approved projects within the Gnatcatcher's habitat could be stopped unless a federal and/or state permit is approved. The permit process can take up to a year or more for each project that applies. Moreover, project-by-project habitat planning often results in isolated fragments of habitat that are of questionable long-term value. A more logical and efficient approach is to pursue a Citywide permit that would specify in advance which lands must be preserved and which lands can be developed. If successful, such an effort would resolve all future endangered species issues for the City. This is what the HMP is intended to accomplish. Current Status Beginning in November 1990, the City Council authorized a Work Program consisting of four phases, as follows: Phase I - Advisory Group Formation and Startup Phase II - Biological Inventory and Analysis Phase III - Plan Development Phase IV - Plan Implementation Page Two of Agenda Bill No. \\fK1'5* Phase II is now completed. Exhibit 1 is the draft Biological Resources and Habitat Analysis Report, prepared by the biological consulting team and reviewed by the advisory group. The report includes a comprehensive inventory of all the remaining wildlife habitat in Carlsbad and shows the documented locations of sensitive species of plants and animals. Based on this inventory, a rating system was used to show the relative habitat value of specified areas. The result is a generalized indication of the areas of highest biological value and the designation of Preserve Planning Areas. Two scenarios were analyzed; one assumes the current status of the California Gnatcatcher as a candidate for listing as an endangered species while the other scenario analyzes the situation after listing. Area 1 Buena Vista Lagoon and Buena Vista Creek Area 2 Portions of Zones 7, 14, 15 and 16 Area 3 Agua Hedionda Lagoon and adjacent lands Area 4 Portions of Zones 20 and 21 Area 5 Zones 10 and 18 Area 6 Batiquitos Lagoon Area 7 A portion of property owned by the Fieldstone Company in Zone 11, which is already covered by a proposed conservation agreement Area 8 A portion of Zone 12 (in post-listing scenario only) The report notes that approximately 2,500 acres of habitat are already protected in Carlsbad. This includes the three lagoons and the Fieldstone preserve land in Area 7. Not all of the remaining Preserve Planning Areas will be preserved for habitat purposes. The report recommends that two or three additional areas of appropriate size be preserved, with suitable linkages to develop a complete, integrated preserve system. In the development of the plan thus far, staff and the consultants have been sensitive to private property rights and the concerns of land owners. Specific parcels have not been targeted for acquisition, and ongoing projects have not been affected by the plan even though sensitive habitat is shown to be present. It is important for all parties to understand that the plan at its present stage is not a regulatory document. It does not prohibit development of any land. It does not supplant the normal environmental review process, and it does not require additional mitigation. It does not change the General Plan designation or zoning of any land, and it specifically does not designate any land as Open Space. It does not require any property owner to give or sell any land to the City. It is not a local endangered species act, and it does not supplant the existing federal and state processes for designating endangered species. The City will benefit from completion of this work in several ways. The City has already benefitted by having the vegetation inventory prepared, which will be very useful in the update of the General Plan and accompanying Master EIR. By proactively addressing the issue of protecting sensitive species, the plan minimizes the economic impacts on the City of future listings of species as threatened or endangered. It will allow municipal projects, such as roads and parks, Page Three of Agenda Bill No. // $ 75 to be more sensitively designed to avoid impacting habitat areas and to more readily provide appropriate mitigation for unavoidable impacts. The process used to arrive at the present plan has forged a stronger cooperative relationship with both the federal and state wildlife agencies, which will have long term benefit to the City. Implementation of a preserve and corridor system will provide additional open space within Carlsbad, benefitting the environment and Carlsbad residents. A less tangible benefit is the positive recognition that Carlsbad will receive for having undertaken this unprecedented effort. Before the City can determine specifically where and how additional wildlife habitat should be preserved, it will be necessary to complete Phase III of the Work Program. Phase III involves the actual preparation of a Habitat Management Plan. This phase deals with identifying the specific areas to be preserved based on the general analysis completed in Phase II. This phase also deals with the questions of how to acquire the land and how it will be maintained and managed in perpetuity for its biological value. The tasks to be carried out are listed in Exhibit^ which is a revised Work Program for Phases HI and IV. The Work Program for these phases has been revised and updated to reflect tasks accomplished in Phase II. It is anticipated that Phase III will be completed by Spring 1993. The firm of Consultants Collaborative Inc. has served as facilitator for Phases I and II. A. D. Hinshaw Associates has served as environmental consultant. Staff believes that the most expeditious way to provide the necessary consultant services for Phase III is to supplement the existing agreement with Consultants Collaborative and A. D. Hinshaw, who will subcontract for needed biological, financial, and other technical expertise. It is recommended that the City Council authorize the City Manager to execute supplements to the existing agreements with Consultants Collaborative and A. D. Hinshaw in a combined amount not to exceed $150,000 to provide necessary consulting services for Phase III. FISCAL IMPACT Funding for the completion of Phase III of the HMP was approved as part of the Planning Department's budget for FY 1992-93. However, as part of the conceptual mitigation agreement with the Fieldstone Company regarding its land in the vicinity of Rancho Santa Fe Road, Fieldstone has agreed to reimburse the City for these costs up to a maximum of $150,000 upon formal acceptance of a final mitigation agreement. ENVIRONMENTAL REVIEW The Habitat Management Plan is a planning study only, and no environmental review is required. If the plan results in a federal or state permit, environmental documentation will be required at that time. Page Four of Agenda Bill No. /// EXHIBITS 1. Biological Resources and Habitat Analysis Report CM fd-z in fi-y Clerk.* ° 2. Revised Phase III and IV Work Program TABLE OF CONTENTS Section Page OVERVIEW 1 1 SAN DIEGO COUNTY, CALIFORNIA: THE REGIONAL SETTING 2 1.1 Introduction \ 2i 1.2 Existing Conditions ^ 2 1.2.1 Regional Overview ^ 2 1.2.2 Topography '. 2 1.2.3 Climate 3 1.2.4 Geology and Soils . .. . r 3 1.2.5 Plant Communities 4 1.2.6 Sensitive Biota 7 1.3 Summary and Conclusions 9 2 CITY OF CARLSBAD: THE LOCAL SETTING 10 2.1 Introduction 10 2.2 Existing Conditions 10 2.2.1 General Topography and Landscape Features 10 2.2.2 Climate 11 2.2.3 Geology and Soils . 11 2.2.4 Plant Communities 11 2.2.5 Sensitive Biota 16 3 RESOURCE INVENTORY AND MAPPING 32 3.1 Introduction 32 3.2 Materials 32 3.3 Methods 32 3.4 Results 33 3.4.1 Vegetation Map 33 3.4.2 Sensitive Species Map 35 TABLE OF CONTENTS (Continued) Page 4 BIOLOGICAL PRESERVE PLANNING AREA AND DESIGN APPROACH 36 4.1 Introduction 36 4.2 Preserve Design Literature Review 36 4.2.1 Size 36 4.2.2 Shape 37 4.2.3 Isolation/Wildlife Corridors 37 4.2.4 Buffers and Distance Setbacks 37 4.2.5 Other Considerations 40 4.3 Preserve Design Rationale and Approach 40 4.4 Preserve Design Methodology 41 4.4.1 Focused Planning Areas 41 4.4.2 Preserve Feature Definitions and Ratings — Habitat Value 42 4.4.3 Preserve Feature Definitions and Ratings - Habitat Sensitivity 45 4.5 Results - Habitat Value 47 4.5.1 Amount of Natural Habitat 48 4.5.2 Habitat Diversity 48 4.5.3 Habitat Connectivity 49 4.5.4 Adjacent Land Use 49 4.5.5 Composite Habitat Value 49 4.6 Discussion - Habitat Value 50 4.7 Results - Habitat Sensitivity 50 4.7.1 Amount of Sensitive Habitat 51 4.7.2 Sensitive Habitat Diversity 51 4.7.3 California Gnatcatcher 51 4.7.4 Sensitive Plants 52 4.7.5 Sensitive Wildlife 52 4.7.6 Composite Habitat Sensitivity 52 4.8 Habitat Sensitivity — Discussion 53 4.9 Total Habitat Value/Sensitivity - Results 53 4.10 Total Habitat Value/Sensitivity -- Discussion 54 4.11 Limitations of Approach 55 in TABLE OF CONTENTS (Continued) Page 5 PRESERVE RECOMMENDATIONS 56 5.1 Introduction 56 5.1.1 Size of Preserve System 56 5.2 Potential Core Preserve Areas 56 5;2.1 Methods 57 5.2.2 Results 57 53 Potential Wildlife Corridors 69 5.3.1 Methods 69 5.3.2 Results 70 5.4 Conceptual Preserve System 72 5.5 Compatible Land Use Analysis 73 5.6 Conclusion 74 6 ACKNOWLEDGEMENTS 75 7 LITERATURE CITED 76 Appendices A. Federal and State Designated Sensitive Plant and Wildlife Species Resident or Breeding in San Diego County B. Environmental Impact Reports and Other Documents Consulted IV TABLE OF CONTENTS (Continued) LIST OF TABLES 1. Comparison of Pre-European and 1988 Vegetation Coverage for San Diego County 5 2. Classification System for Habitat Communities Occurring in the City of Carlsbad 12 3. Acreages by Aggregated Vegetation Types within the Carlsbad Habitat Management Plan Study Area 34 4. Frequency Distribution for Habitat Value Features 48 5. Composite Habitat Value 50 6. Frequency Distribution for Habitat Sensitivity Features 51 7. Composite Habitat Sensitivity 53 8. Total Habitat Value/Sensitivity Frequency Distribution 54 9. Acreages by Aggregated Vegetation Types for the Pre-California Gnatcatcher Listing Preserve Planning Areas 58 10. Acreages by Aggregated Vegetation Types for the Post-California Gnatcatcher Listing Preserve Planning Areas 60 11. Pre-California Gnatcatcher Listing Preserve Planning Area Sensitive Species Records 63 12. Post-California Gnatcatcher Listing Preserve Planning Area Sensitive Species Records 64 LIST OF FIGURES Follows Page 1. Regional Map 2 2. Vicinity Map 10 3. Vegetation Map 33 4. Sensitive Species Map (Sheets 1 & 2) 35 5. Pre-Gnatcatcher Listing Focused Planning Areas 41 6. Post-Gnatcatcher Listing Focused Planning Areas 41 7. Habitat Value Map 49 8. Habitat Sensitivity Map 52 9. Total Habitat Value/Sensitivity Map 53 10. Pre-Listing Proposed Preserve Planning Areas/Corridors 57 11. Post-Listing Proposed Preserve Planning Areas/Corridors 57 OVERVIEW THE CARLSBAD HABITAT MANAGEMENT PLAN At the direction of the Carlsbad City Council, the Community Development Department has undertaken preparation of a Habitat Management Plan (HMP) for the City. The goals of the project are to develop an HMP that will: (1) constitute a major component of the Conservation Element of the General Plan; and (2) result in implementation of a plan that will proactively address protection of sensitive plant and animal species and their habitats as development occurs in Carlsbad. The HMP will provide direction about how best to identify, conserve, use, and manage the City's biological habitat resources and should result in an effective habitat preserve system. Decisions regarding the design of the preserve system will be based on scientific theory and be consistent with current knowledge from the field of conservation biology. A broadly based Citizens Advisory Group that contains representatives of land owners, environmental groups, state and federal regulatory agencies, and City operating departments provides input and oversight to the project. SECI ON SAN DIEGO COUNTY, CALIFORNIA: The Regional Setting BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the QlT OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 1 SAN DIEGO COUNTY, CALIFORNIA THE REGIONAL SETTING 1.1 INTRODUCTION This section provides an overview of the regional setting in which the HMP is being developed. Other jurisdictions within San Diego County are currently undertaking or considering similar natural resources planning programs. While Carlsbad's plan is intended only to address land and habitats within its corporate limits, it is important in formulating such a plan to be aware of regional issues and other programs. As such, the Carlsbad HMP is intended to be consistent with three known subregional programs - the San Diego Clean Water Program Multi-Species Conservation Program (MSCP), the County of San Diego Open Space and Habitat Management Plan (OSHMP), and the North County Multiple Habitat Conservation Program (MHCP), as well as the anticipated Central County Wildlife Forum Plan. The plan also is intended to be consistent with the pilot Natural Communities Conservation Planning (NCCP) for coastal sage scrub habitat in Southern California. This state program, if successful, would provide regional resource planning and protection for coastal sage scrub and its threatened plant and wildlife species. 1.2 EXISTING CONDITIONS 1.2.1 REGIONAL OVERVIEW San Diego County, California, is the most southwesterly county in the continental United States. It is bordered on the east by Imperial County, on the north by Riverside and Orange counties, on the west by the Pacific Ocean, and on the south by Baja California, Mexico (Figure 1). Roughly trapezoidal in shape, it extends about 70 miles (110 km) from east to west and 60 miles (80 km) from north to south; it covers approximately 4,250 square miles (7,000 square km). Elevations range from sea level along the coast to 6,533 feet (2,000 m) at the highest point — Hot Springs Mountain near Warner Springs. San Diego County supports an exceptionally diverse biota (i.e., the animal and plant species of a region): over 1,500 species of plants (Beauchamp 1986), 160 breeding and about 275 non-breeding species of birds (McCaskie 1977), 75 species of reptiles and amphibians (Lichtwardt and Gold 1980), 125 resident species of butterflies (Brown 1991), 80 species of mammals (Bond 1977), and an estimated 10,000 to 20,000 species of terrestrial and aquatic invertebrates. A number of factors combine to support this rich biodiversity, including varied topography, complex climatic conditions, a wide variety of soil types, and a unique biogeographic history. San Diego County is also one of most rapidly-growing areas of the country. Because the greatest human population expansion and habitat change are occurring primarily along the coast where the most sensitive biological resources occur, the conflicts of growth and maintenance of biological diversity are acute. Planning has not previously been done on a regional scale for this area resulting in a highly fragmented natural landscape. This, in turn, makes preserve design more difficult and necessitates designation or creation of wildlife corridors to interconnect habitat fragments. 1.2.2 TOPOGRAPHY Physical features found along the western edge of the county include sandy beaches, wide river floodplains, low-lying salt marshes, and rocky bluffs. These areas support coastal dune, coastal salt H m Orange County p p iii CARLSBAD Mi PI IP I* MEX/CO No Scale Carlsbad Habitat Management Plan Regional Map marsh, Torrey pine woodland, and maritime succulent scrub plant communities. Inland from the coast a series of coastal mesas, foothills, and canyons support coastal sage scrub, southern mixed chaparral, chamise chaparral, and oak and riparian woodland communities. Further inland are the foothills of the Peninsular Range Mountains, covered primarily with chamise chaparral, southern mixed chaparral, and oak woodlands. Riparian woodlands occur along watercourses. The county is bisected north to south by an extension of the Peninsular Ranges, including the Palomar, Cuyamaca and Laguna Mountains, which constitute a formidable barrier between the broad chaparral belt to the west and the arid lowlands of the Colorado Desert to the east. The mountains reach peak elevations of over 6,000 feet above sea level (1,850 m) before dropping sharply to near sea-level in the Anza-Borrego Desert. The mountainous areas support chaparral, oak woodland, montane coniferous forest, mixed evergreen forest, and riparian woodlands. The desert is topographically diverse, extending from the eastern slopes of the mountains to far beyond the eastern border of the county. This region is vegetationally diverse as well, supporting chaparral, pinyon-juniper woodland, creosote bush scrub, alkaline sink, dune, playa, and riparian habitats. 1.2.3 CLIMATE Based on average temperature and precipitation, San Diego County includes four natural climatic zones (Pryde 1984): (1) cool Mediterranean, (2) warm Mediterranean, (3) semiarid (or steppe), and (4) arid (or desert). All of these climatic zones are characterized by cool, moist winters and hot, dry summers. Within these four types, topographic features and proximity to the ocean combine to create a diversity of specific micro-climatic regimes within the county. Along the narrow coastal strip, fog constitutes a major source of water for many native plants. Average precipitation along the coast ranges between 10 and 12 inches (25-30 cm) per year. Proximity to the ocean helps maintain relatively constant temperatures. The lowland mesas (also known as marine terraces) are slightly warmer than the immediate coast and receive slightly more precipitation - 12 to 16 inches (30-40 cm) per year. Above about 1,300 feet (400 m) elevation, the mountainous areas receive considerably more precipitation than the coastal and mesa areas to the west, and the vegetation is taller and denser. Above about 3,900 feet (1,200 m) elevation, temperature and precipitation regimes support coniferous forests. Winter snow is infrequent but regular in the higher elevations of the mountains. The rain-shadow effect of the mountains on lands further east, inhibiting moisture-laiden clouds from reaching further inland, is manifested in dry, desert conditions that prevail throughout most of the year. Desert temperatures are extremely variable; summer temperatures typically exceed 100 degrees Fahrenheit (38 degrees Celsius) in the lower valleys. 1.2.4 GEOLOGY AND SOILS San Diego County is divisible into two large geomorphic provinces on the basis of surface geology and relief (Pryde 1984). The Coastal Province occupies the western portion of the county, corresponding to the region of sedimentary surface rocks. The dominant relief of this province is a series of marine terraces also known as mesas. The Peninsular Range Province comprises the portion of the county located east of the Coastal Province and is composed of plutonic and metavolcanic surface rocks. The major relief elements of this province include the general northwest-southeast trending foothills and mountain ranges, the highest peaks, and the steep eastern slopes of the mountains. According to Bowman (1973), 53 different soil series are present in San Diego County, including sandy, cobbly, loamy, and clayey, and soils associated with gabbro parent material and Santiago Peak metavolcanic formations. A soil series is a group of closely related soils that shares similar texture of surface, slope, stoniness, and other characteristics that affect use of the soil by man. On the coastal terraces most of the soil series are comprised of sandy loams, clay loams, and clays. In the foothills on the western slopes of the mountains, the soils generally are well-drained sandy loams or silt loams overlaying decomposed granitic or metavolcanic rock. The mountainous areas are characterized by well-drained sandy loams over granitic bedrock. In the desert, soils range from virtually none on the steeper slopes, to coarse sandy alluvial soils on the gentler slopes. Soil diversity acts to promote botanical diversity: many endemic plant species are confined to a single or a few soil types (Oberbauer 1991 a). 1.2.5 PLANT COMMUNITIES A plant community is an association of plant species that is readily recognizable in the field. Plant communities are thought to reflect particular biogeographic and ecological conditions. Plant communities are recognized by their "dominant" species, which tend to occur together. Plant communities are closely related to climatic zones, available moisture, slope aspect (exposure), soil type, and disturbance. For some communities, such as coastal sage scrub, chaparral, and southern interior cypress forest, fire plays an integral role in community succession and is necessary to maintain the integrity and productivity of the habitat (Zedler 1977). For other communities, perturbations may have very long-lasting dramatic effects. Plant communities are the major determinants of wildlife diversity and abundance, and they play a vital role in determining species distributions. The major plant communities present in San Diego County are discussed briefly below (see Table 1). Terminology in the table is after Oberbauer (1991b) while the terminology in the text follows Holland (1986). Plant communities present along the coastal strand include a number of dune communities (i.e., active coastal dunes, southern foredunes, and southern dune scrub). The plants of these communities typically are small herbaceous or succulent species, often with a prostrate growth habit. They cover the surface sparsely, leaving areas of bare sand. The general aspect of this community is determined by nearly constant onshore breezes, fine sandy soils, and moderately saline conditions. Among the most common species in this habitat type are sea-rocket (Cakile maritima), beach evening-primrose (Camissonia cheiranthifolia), beach bur (Ambrosia chamissonis), and sea-fig (Carpobrotus spp.). Coastal strand vegetation has been replaced in most areas by recreational or urban development, and elsewhere it has been degraded by frequent human disturbance. Dune communities are best preserved at Border Field and Silver Strand State Parks. In all other coastal areas throughout the county, coastal strand or dune communities are extremely limited. Wetland communities found along the coastal strand include southern coastal salt marsh, coastal brackish marsh, and coastal and valley freshwater marsh. In these aquatic and semi-aquatic habitats, plant species composition varies considerably, depending upon duration of inundation, tidal flow or runoff, and salinity. Salt marshes are characterized by low-growing succulents such as pickleweed (Salicornia spp.), salty susan (Jaumea camosa), salt grass (Distichlis spicata), salt-cedar (Monanthochloe littoralis), and other halophytic (salt-tolerant) species. Some salt marsh systems include an outer marsh characterized by stands of tall cordgrass (Spartina foliosd). Salt marsh communities are highly productive systems and function as hatcheries for many species of fish, and provide food and refuge resources for a variety of locally resident and migratory water birds. Salt marsh habitat is best developed at places like Tijuana Estuarine National Wildlife Refuge, the mouth of the Sweetwater River, and the mouth of the Santa Margarita River. Freshwater marshes typically are dominated by cattails (Typha spp.), bulrushes (Scirpus spp.), and dock (Rwnex spp.). Patches of this habitat are present at the upper ends of Buena Vista, Agua Hedionda, Batiquitos, and San Elijo lagoons, where a mixture of plants of salt and freshwater habitats is encountered. Smaller freshwater marshes grow around the perimeter of many lakes and ponds on the coastal slope. TABLE 1 COMPARISON OF PRE-EUROPEAN AND 1988 VEGETATION COVERAGE FOR SAN DIEGO COUNTY (AFTER OBERBAUER 199th1) Original Ac. Current Ac. Change Chamise Chaparral2 Creosote Bush Scrub Mixed Chaparral2 Coastal Sage Scrub2'3 Desert Transition Native Grassland2 Oak Woodland (sparse) Coniferous Forest Riparian Woodland2 Oak Woodland (dense)2 Desert Wash Coastal Mixed Chaparraf Mountain Meadow Juniper Woodland Pinon Woodland Coastal Salt Marsh2 Creosote Bush-Wash Complex Mesquite Bosque Cypress Woodland Coastal Strand2 Dry Lake-sink Freshwater Marsh2 Torrey Pine Woodland Agriculture-Urban complex4 Disturbed Grassland4 Agriculture4 Lakes/Reservoirs4 Total 2,709,360 Direction of Change 599,820 532,290 500,540 480,260 143,680 125,680 80,500 79,010 34,580 28,900 21,040 20,620 16,480 12,230 8,190 6,530 5,040 4,610 4,440 1,940 1,580 1,090 310 0 0 0 0 466,947 500,220 467,715 135,370 143,680 7,250 78,540 79,010 13,570 27,140 21,040 2,530 16,480 12,230 8,190 810 5,040 4,209 4,229 0 1,580 100 250 339,030 203,760 159,640 10,800 22% 6% 7% 72% 0% 94% 2% 0% 61% 6% 0% 88% 0% 0% 0% 68% 0% 9% 5% 100% 0% 91% 19% 100% 100% 100% 100% Reduction Reduction Reduction Reduction No Change Reduction Reduction No Change Reduction Reduction No Change Reduction No Change No Change No Change Reduction No Change Reduction Reduction Essentially gone No Change Reduction Reduction New Type New Type New Type New Type 2,709,360 i _ 4 _ After: Oberbauer, T.A. 1991. In: Abbott, P. and B. Elliot. Geol. Soc. North Amer., So. Calif. Reg., Sympos. Oct.-21-24,1991, San Diego, California. Does not follow Holland (1986) precisely. Occurs in Carlsbad Oberbauer splits coastal sage scrub into two components: inland sage scrub and maritime sage scrub. Inland sage scrub has been reduced from 428,480 acres to 131,000 acres (a 69% reduction). Maritime sage scrub has been reduced from 51,780 acres to 4,370 acres (a 92% reduction). Man made Terrestrial upland vegetation closest to the coast includes Diegan coastal sage scrub, southern coastal bluff scrub, maritime succulent scrub, southern maritime chaparral, and Torrey pine forest. Diegan coastal sage scrub consists primarily of aromatic shrubs and sub-shrubs with an understory of annual herbs and perennial grasses. Characteristic species include coastal sagebrush (Artemisia California), California buckwheat (Eriogonum fasciculatuni), white sage (Salvia apiand), lemonadeberry (Rhus integrifolia), laurel sumac (Malosma laurind), and purple needlegrass (Stipa pulchra). Typical coastal sage scrub occurs in many places, including the hills around Poway, the Dulzura-Jamul area, south of Lake Hodges, and portions of Camp Pendleton. Southern coastal bluff and maritime succulent scrub include a variety of succulents and cacti, such as velvet cactus (Bergerocactus emoryi), fish-hook cactus (Mammillaria dioica), coast cholla (Opuntia proliferd), San Diego barrel cactus (Ferocactus viridescens), prickly-pear cactus (Opuntia littoralis), cliff-spurge (Euphorbia miserd), bladder-pod (Cleome isomeris), and several species of dudleya (Dudleya spp.), mixed with typical sage scrub species. This community type is well developed at Torrey Pines State Park, Tijuana Hills above Border Field State Park, and Cabrillo National Monument. Southern maritime chaparral is limited to the area between Mount Soledad and southern Carlsbad. It is a community characterized by several endemic shrubs, usually growing on sandstone: Del Mar Manzanita (Arctostaphylos glandulosa var. crassifolid), wart-stemmed ceanothus (Ceanothus verrucosus), coast spice bush (Cneoridium dumosuni), mission manzanita (Xylococcus bicolof), and Del Mar mesa sand-aster (Corethrogyne filaginifolia var. linifolia). Torrey pine forest is an exceedingly restricted community known only from the vicinity of Del Mar and Torrey Pines State Reserve in San Diego County. It is an open-to- moderately dense forest dominated by Torrey pine (Pinus torreyana), with an extremely variable understory. Scattered on flat-topped mesas, marine terraces, and some valleys is a unique habitat that is, unfortunately, one of the most depleted habitat types in San Diego County — vernal pools (San Diego Mesa hardpan vernal pool and Otay Mesa claypan vernal pool). These small shallow pools develop in "mima mound" topography where an underlying semi-impermeable hardpan layer intercepts winter rainfall and creates a perched water table. Vernal pools support a unique and ephemeral aquatic and semi-aquatic biota, quite distinct from the adjacent chaparral or grassland, that includes several plant species recognized as rare, threatened, or endangered by local, regional, and national conservation agencies, including San Diego mesa mint (Pogogyne abramsii), Otay mesa mint (Pogogyne nudiuscula), San Diego button-celery (Eryngium aristulatum var. parishii), California Orcutt grass (Orcuttia califomica), and San Diego navarretia (Navarretia fossalis). Vernal pools are found in several areas of the county, including Otay Mesa, Kearny Mesa, Del Mar Mesa, Clairemont Mesa, San Marcos, Ramona, and Fletcher Hills (Bauder 1986). Inland from the coast, chaparral is the dominant plant community, covering about 35 percent of the county's land surface. Although several types of chaparral are recognized by Holland (1986) (i.e., southern mixed chaparral, chamise chaparral, scrub oak chaparral, mixed montane chaparral, mesic north slope chaparral, and southern north slope chaparral), all are composed of tall shrubs with hard evergreen leaves and stiff woody stems. Plant species composition varies from region to region within the county, but dominant species usually include chamise (Adenostoma fasciculatuni), manzanitas (Arctostaphylos spp. and Xyloccocus bicolof), wild-lilac (Ceanothus spp.), toyon (Heteromeles arbutifolia), mountain-mahogany (Cercocarpus spp.), Spanish bayonet (Yucca whipplei), and interior scrub oak (Quercus berberidifolid). Fire plays an integral role in the succession of chaparral communities, and many of the resident plant species are highly adapted for vigorous vegetative reproduction (crown- and stump-sprouting) following fires. Occurring throughout the coastal area and into the foothills and mountains are several types of natural grasslands that often are associated with clayey soils. Coastal perennial grasslands may range in size from patches within sage scrub or chaparral that are less than 100 square feet to (rarely) 20 to 100 acres. They often are dominated by purple needlegrass, a number of non-native grasses (i.e., Avena spp., Bromus spp., Gastridium ventricosum, Vulpia spp.), sanicles (Sanicula spp.), blue-eyed grass (Sisyrinchium bellum), and gum-plant (Grindelia robusta). Riparian woodlands (i.e., southern coast live oak riparian forest, southern arroyo willow riparian forest, southern cottonwood-willow riparian forest, and southern willow scrub) cover less than 0.5 percent of the county's area. Although small in acreage, these woodlands support the highest diversity and greatest abundance of wildlife species of any community type; riparian woodlands are noted for their rich diversity of breeding bird species (Unitt 1984). Riparian habitats play a vital role in nutrient recycling and in water quality maintenance. Along large, perennial river courses and smaller, seasonally moist drainages, the woodlands are comprised of willows (Salix spp.), Fremont cottonwood. (Populus fremontii), and western sycamore (Platanus racemosd), with a tangled understory of poison-oak (Toxicodendron diversilobum), desert grape (Vitis girdiana), and a variety of other hydrophytic (wetland) species. Canyon bottoms that do not have enough water to support the full complement of riparian vegetation often contain sycamores. In drier canyon bottoms, on north-facing slopes, and along the edges of valleys, dense groves of coast live oak (Quercus agrifolia) form a closed canopy oak woodland. Another type of oak woodland occurs in some parts of the foothill region, where widely spaced individuals of the endemic Engelmann oak (Quercus engelmannii) form a sparse woodland or oak savannah. Coniferous woodland communities (Jeffrey pine forest, western ponderosa pine forest, and Coulter pine forest) are restricted to montane habitats and some isolated peaks that receive over about 18 inches (46 cm) of rain per year. Pines (Pinus spp.) are the dominant plants of this community, but canyon live oak (Quercus chrysolepis), black oak (Quercus kelloggii), and wild-lilac (Ceanothus spp.) also are important components. The composition and character of this community vary with humidity and exposure. In drier, flatter areas, the trees are more widely spaced, there is little ground cover, and Jeffrey (Pinus jejfreyi) and Coulter pines (Pinus coulteri) dominate. In more humid areas, such as Cuyamaca Mountain, Palomar Mountain, or on steep north-facing slopes, conifers are more diverse, and the flora includes incense-cedar (Calocedrus decurrens), white fir (Abies concolor), big- cone Douglas-fir (Pseudotsuga macrocarpd) and sugar pine (Pinus lambertiana). Scrub vegetation covers most of the desert edge at the steep eastern escarpment of the mountains between about 2,500 and 4,000 feet (760-1,220 m). This area includes elements of chaparral and creosote bush scrub (described below), as well as plant species found sparingly in other areas the county. The most prominent of these are California juniper (Juniperus califomica), turpentine broom (Thamnosma montana), and desert apricot (Prunus fremontii). Most of the lower desert area is covered by a sparse scrub community known as Sonoran creosote bush scrub. Creosote bush (Larrea tridentatd) is the dominant shrub, but the density of plants is much lower than that found in other vegetational communities. Sub-dominants in this habitat include ocotillo (Fouqueria splendens), brittlebush (Encelia farinosa), barrel cactus (Ferocactus acanthodes), and burrobush (Ambrosia dumosa). Other communities found in this drier eastern portion of the county include active desert dune, Sonoran mixed woody and succulent scrub, desert greasewood scrub, desert dry wash woodland, and peninsular juniper woodland and scrub. Although dry and desolate during most of the year, the desert areas usually come to life in the spring following normal winter rainfall. Wildflower displays may be magnificent during this brief flowering season. 1.2.6 SENSITIVE BIOTA Southern California has a long history of human use and consequent alteration of the ecosystem, but it has experienced rapid urban expansion and habitat change over the past three or four decades; San Diego County has not been immune. Although habitat degradation has occurred throughout much of the county, the coastal areas have been altered the most severely. As well as providing prime sites for housing and other development, these areas have been disrupted by the abuses of recreation and off-road vehicles. According to the City of San Diego (Hix 1990), the native coastal strand community has been eliminated nearly entirely; coastal salt marsh has been reduced by greater than 87 percent; coastal sage scrub has lost over 70 percent of its previous acreage; vernal pool habitats have been reduced by 96 percent; and coastal mixed chaparral has declined by more than 87 percent in San Diego (see Table 1). The net overall result of this considerable loss in native habitat is the concurrent decrease in native wildlife and plant species. (See Appendix A for lists of wildlife and plant species in San Diego County with federal and state sensitive species designations.) Several species of birds associated with disappearing habitat types and/or habitat degradation are recognized as threatened or endangered by state or federal agencies: California brown pelican (Pelecanus occidentalism light-footed clapper rail (Rallus longirostris levipes), Belding's Savannah sparrow (Ammodramus sandwichensis beldingi), and California least tern (Sterna antillarum browni), all associated with coastal estuaries and salt marsh habitats; and least Bell's vireo (Vireo belliipusillus), restricted to riparian woodlands. Also receiving much attention is the federal proposed endangered California gnatcatcher (Polioptila califomicd), occurring primarily in coastal sage scrub communities below about 1,200 feet (370 m). Other species recognized as sensitive include coastal cactus wren (Campylorhynchus brunneicapillus sandiegensis), sage sparrow (AimophUa belli), Southern California rufous-crowned sparrow (AimophUa ruficeps canescens), California horned lark (Eremophila alpestris actia), and several species of raptors (birds of prey). Mammal species occurring in San Diego County listed as threatened or endangered by the U.S. Fish and Wildlife Service (USFWS) or the California Department of Fish and Game (CDFG) include Stephens' kangaroo rat (Dipodomys Stephens!), found in the northwestern portion of the county and on Camp Pendleton; and peninsular bighorn sheep (Ovis canadensis cremnobates), an inhabitant of the rugged hills in the desert portion of the county. The ringtail (Bassariscus astutus), a state fully protected species, occurs in riparian, scrub, and forest habitats in the county. The CDFG recognizes 20 species of mammals that occur within San Diego County as "Species of Special Concern," including eight species of bats. Species that are both federal Category 2 candidates and on the state list of sensitive species include the Pacific pocket mouse (Perognathus longimembris paciftcus), the Los Angeles pocket mouse (Perognathus longimembris brevinasus), and four bats. In addition, there are several new federal Category 2 candidates that are not yet designated by the State as sensitive species (see Appendix A). Reptiles that are recognized as federal Category 1 or 2 candidates for listing as endangered by the USFWS or as Species of Special Concern by CDFG include the San Diego horned lizard (Phymosoma coronation blainvillei), orange-throated whiptail (Cnemidophorus hyperythrus beldingi), northern red-diamond rattlesnake (Crotalus ruber), coastal whiptail (Cnemidophorus tigris multiscutatus), barefoot banded gecko (Coleonyx switald), and San Diego mountain kingsnake (Lampropeltis zonata pulchra). Sensitive or declining amphibians include western spade-foot toad (Scaphiopus hammondi), reg-legged frog (Rana aurora draytoni), and arroyo toad (Bufo [microscaphus califomicus] califomicus). Seven species of butterflies indigenous to San Diego County are recognized as federal Category 2 candidates for listing as threatened and endangered, namely the Laguna Mountains skipper (Pyrgus ruralis lagunae), wandering skipper (Pseudocopaeodes eunus), Harbison's dun skipper (Euphyes vestris harbisoni), salt marsh skipper (Panoquina errans), Hermes copper (Lycaena hermes), Thome's hairstreak (Mitoura thomef), and quino checkerspot (Euphydryas editha quind). The USFWS has been petitioned to list several of these species as endangered. Also, the globose dune beetle (Coelus globosus), a resident of coastal dunes, is a federal Category 2 candidate species, and two other invertebrates — the Riverside fairy shrimp (Streptocephalus woottonii) and San Diego fairy shrimp (Branchinecta sandiegoensis) have been proposed or petitioned to be listed as endangered. 8 San Diego County exhibits an exceptionally high degree of floral endemism - it contains numerous plant species that are found nowhere else. With 173 species recognized as sensitive by the California Native Plant Society (Smith and Berg 1988), San Diego County is second only to San Bernardino County in this regard. Plant species of San Diego County listed as threatened or endangered by the USFWS include salt marsh bird's-beak (Cordylanthus maritimus), restricted to coastal salt marshes, and San Diego mesa mint (Pogogyne abramsii), an inhabitant of San Diego Mesa hardpan vernal pools. State-listed rare, threatened, or endangered plant species include the two listed above, plus San Diego thornmint (Acanthomintha Uicifolia), coastal dunes milk vetch (Astragalus tener var. titi), Encinitas baccharis (Baccharis vanessae), Dunn's mariposa lily (Calochortus dunni), San Diego button- celery (Eryngium aristulatum var. parishii), and many others. The USFWS recognizes 76 species of local plants as federal Category 1 or 2 candidates, and they have proposed three species for listing as endangered: Otay mesa mint, San Diego button-celery and California Orcutt grass. San Diego County also supports a variety of sensitive habitats. A sensitive habitat is defined as a vegetation community type that has been significantly depleted due to development and has been identified as warranting protection by the CDFG (e.g., coastal sage scrub, coastal strand, or coastal salt marsh), uncommon within a region, but common elsewhere (e.g., Jeffrey pine forest is limited in San Diego County), as habitat that supports rare, endangered, or threatened plant or animal species, or areas that are needed to maintain a balanced ecosystem or wildlife corridor (City of San Diego 1991). Sensitive habitats in San Diego County relevant to the City of Carlsbad and this document are coastal sage scrub (including all subassociations), southern maritime chaparral, oak woodland, riparian scrub, freshwater marsh, salt marsh, open water, and native grassland. 1.3 SUMMARY AND CONCLUSIONS Because of its highly varied topography, soils, and climatic conditions, San Diego County supports an exceedingly diverse biota. Numerous plant communities are present within the county boundaries, each of which supports its own distinctive assemblage of plant and wildlife species. Urban growth throughout San Diego County has had a tremendous effect on the local biota. Many plant and animal species have become increasingly rare throughout the region and some have become locally extinct. Projected land development and human population growth in the region will increase the pressure on a large number of habitats and species that are literally now on the brink of extinction. Although sensitive species are designated as threatened, endangered, rare, declining, or depleted by local or regional conservation agencies, sensitive habitats are not provided with such designations. The most depleted habitat types include coastal dunes, coastal salt marsh, maritime succulent scrub, coastal sage scrub, native grassland, riparian woodland, and vernal pool. The loss of natural habitat results in the decline of native plant and wildlife species. San Diego County is one of the most desirable places in the country to live. In order for the region to continue to offer a high quality of human life, severe challenges in natural resource management must be met, including preservation of open space, maintenance of water and air quality, traffic management, control of noise pollution, and preservation of our natural heritage. Concurrently, the economic vitality of the region must be maintained and enhanced for the present and the future. To achieve these objectives, it is vital to design and implement development alternatives that are compatible with the preservation of biological resources. Habitat management plans, such as that under development by Carlsbad, and similar plans being undertaken by government and individuals, provide a means for attaining this goal. SECT ON 1 CITY OF CARLSBAD: The Local Setting BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 2 CITY OF CARLSBAD THE LOCAL SETTING 2.1 INTRODUCTION The City of Carlsbad is situated along the Pacific coast of California, in northwestern San Diego County, approximately 30 miles (45 km) north of the City of San Diego. It is bordered on the north by the City of Oceanside, on the northeast by the City of Vista, on the east by the City of San Marcos, on the south by the City of Encinitas, and on the west by the Pacific Ocean (Figure 2). It extends about 4.5 miles (6 km) from east to west and about 7.0 miles (9 km) from north to south; it covers approximately 40 square miles (about 24,000 acres or 15.44 square Km). Elevations range from sea level along the coast to about 960 feet (280 m) at the highest point at the southeastern border of the City. The City of Carlsbad has been a valuable agricultural area since prior to the 20th century, and has experienced significant urban expansion over the past three or four decades. The human population of the City is estimated to be approximately 63,000. Urban development for housing and other uses has resulted in degradation and outright loss of significant blocks of native habitat. Encampments of migrant workers and homeless people also have degraded much habitat, particularly in riparian areas. Native communities associated with the coastal areas have been disrupted by the abuses of active recreation and off-road vehicles. Although much of the City has been subject to agriculture, housing, commercial development and other uses, open space areas within Carlsbad support a diverse biota and a variety of sensitive plant and wildlife species. Over 300 species of plants, 200 species of birds, 25 species of reptiles and amphibians, 20 species of mammals, 44 species of fish, 45 species of butterflies, and several thousand species of terrestrial and aquatic invertebrates retain populations within the City. Information on the status of many of these populations, however, is lacking, and it is not known whether the remaining populations of these species are viable. As with much of San Diego County, the City of Carlsbad has experienced significant urban growth in recent years. The entire City lies within 4.5 miles of the coast; hence human population expansion and habitat change is concentrated within the coastal area where many sensitive and rapidly diminishing biological resources occur. Consequently, conflicts between urban growth and the maintenance of biological diversity are encountered frequently. These factors make conservation planning in these areas particularly challenging. 2.2 EXISTING CONDITIONS 2.2.1 GENERAL TOPOGRAPHY AND LANDSCAPE FEATURES The western edge of the City, lying along the Pacific coast, is characterized by sandy beaches and three low-lying river estuaries or lagoons ~ Batiquitos Lagoon, Agua Hedionda Lagoon, and Buena Vista Lagoon. Buena Vista Lagoon, at the northern border of the City, is fed by Buena Vista Creek, a local drainage that forms much of the border between the cities of Oceanside and Carlsbad. The watershed of Agua Hedionda Lagoon includes a drainage that extends from Lake Calavera in the northeastern corner of Carlsbad. Batiquitos Lagoon lies along the southern boundary of the City and extends inland from the coast to near El Camino Real, where it receives runoff from slopes on the north side of the lagoon and a drainage from the south. The lagoons dominate the coastal landscape 10 Oceans/da o TV o o City of Carlsbad \ n Vista San Marcos OUtCNHAJN Rflt Olivenhain Encinitas BlVD 1" = 6500' Carlsbad Habitat Management Plan Vicinity Map of Carlsbad and provide habitat for a variety of resident and migratory bird species. With the exception of some habitat that immediately borders the estuaries, native communities on the immediate coast either have been degraded severely by human activities or have been lost altogether to development. Inland from the coast is a series of low coastal mesas and rolling foothills, supporting shrublands, grasslands, and agriculture, with intervening ravines and canyons supporting narrow oak woodland, riparian scrub, coastal sage scrub, and chaparral communities. Two large freshwater bodies occur within Carlsbad near the eastern edge of the City — Lake Calavera and Squires Dam. Both support adjacent freshwater marsh and riparian woodlands. A deep, roughly east- west trending gorge dominates the landscape locally in the southeastern portion of the City through the Fieldstone Company-owned lands east of La Costa. Agriculture (including tomatoes, flowers, and others) is a dominant feature of the landscape, particularly in the area north of Palomar Airport Road east of Paseo del Norte, and south of Palomar Airport Road east of El Camino Real. Private golf courses also occupy considerable areas of open space, including courses associated with the La Costa and Aviara developments. Golf courses typically occupy lower, more level bottomland areas between steep or sloping terrain. 2.2.2 CLIMATE Based on average temperature and precipitation, the City of Carlsbad lies entirely within the semiarid (or steppe) climatic zone (Pryde 1984). Average annual precipitation is 10.7 inches. Average annual temperature is 59.2 degrees Fahrenheit (F); average July/August high temperature is 72.9 degrees F; and average January low temperature is 42.6 degrees F. Temperatures typically exhibit greater differences furthest from the coast. Highly seasonal rainfall generally occurs between October and April; coastal fog is common in May and June. 2.23 GEOLOGY AND SOILS The City of Carlsbad lies entirely within the Coastal Geomorphic Province, which occupies the western portion of San Diego County corresponding to the region of sedimentary surface rocks. The dominant relief of this province is a series of marine terraces also known as mesas. According to Bowman (1973), 33 different soil series are present in the City of Carlsbad, including sandy, cobbly, loamy, and clayey types, and soils associated with gabbro parent material and Santiago Peak metavolcanic formations. On the coastal terraces most of the soil series are comprised of sandy loams, clay loams, and clays. In the foothills the soils generally are well-drained sandy loams or silt loams overlaying decomposed granitic or metavolcanic rock. 2.2.4 PLANT COMMUNITIES Eight distinct native plant communities (Holland 1986) are present within the City of Carlsbad (see Section 3 for details of mapping). In addition, three non-native habitat types (i.e., eucalyptus woodland, disturbed wetland or floodplain, and disturbed habitat), open water, and development also account for significant areas within Carlsbad (see Section 3 for discussion). These native and non- native habitat types are discussed below with respect to their general habitat structure, species composition, and general location within the City of Carlsbad. Terminology and definitions of the natural communities follow Holland (1986), for the most part, with modifications to conform with community types recognized by Ogden Environmental and Energy Services (in their Multi-species Conservation Plan [MSCP] mapping efforts) and SANDAG (Table 2). 11 TABLE 2 Habitat Type CLASSIFICATION SYSTEM FOR HABITAT COMMUNITIES OCCURRING IN THE CITY OF CARLSBAD SANDAG Code Holland Code Coastal Sage Scrubs coastal sage scrub disturbed coastal sage scrub maritime succulent scrub Chaparrals southern mixed chaparral chamise chaparral southern maritime chaparral coastal sage scrub/chaparral Grasslands non-native (annual) grassland native (perennial) grassland Saltwater Marsh Freshwater Marsh Sycamore Alluvial Woodland Riparian Scrub Oak Woodland Eucalyptus Woodland Open Water Disturbed Wetland Disturbed Habitat Active Disturbance Active Agriculture Golf Course Developed 30 31 40 52 53 60 70 82 83 90 100 123 130 140 190 200 210 240 242 243 244 250 32000 32001 32400 37120 37200 37630 37G 42200 42100 52100 52400 62400 63000 71100 Source: MSCP Habitat Type (modified from Holland 1986). Coastal Sage Scrub Within the City of Carlsbad, coastal sage scrub is represented by Diegan coastal sage scrub and maritime succulent scrub, as well as disturbed forms of both types. Diegan coastal sage scrub is a drought-deciduous community comprised of aromatic shrubs and subshrubs with a diverse understory of annual and perennial herbs, perennial and annual grasses and grass-like plants. Diegan coastal sage scrub occurs primarily on dry south-facing slopes and hillsides or on clay-rich soils adjacent to chaparral or upslope from riparian woodlands. Characteristic species include coastal sagebrush, California buckwheat, black sage (Salvia mellifera), white sage, lemonadeberry, laurel sumac, and purple needlegrass. It also supports a variety of sensitive plant species, including California adolphia (Adolphia califomica), ashy spike-moss (Selaginella cinerascens), San Diego sand-aster, and several others. Sensitive wildlife species that occur primarily in coastal sage scrub include San Diego horned lizard, orange-throated whiptail, California gnatcatcher, and coastal cactus wren. Coastal sage scrub 12 frequently occurs in a mosaic distribution with native grasslands and occasionally with chaparral. The largest remaining tracts of Diegan coastal sage scrub are found in the vicinity of Lake Calavera, southeast of Agua Hedionda Lagoon, and near Rancho Santa Fe Road. Maritime succulent scrub includes a variety of succulents, such as fish-hook cactus, coast cholla, California desert thorn (Lycium californicurri), cliff-spurge, bladder-pod, and several species of dudleya (Dudleya spp.), mixed with typical Diegan sage scrub species. This community type is found along the remaining narrow upland borders of the lagoons and on some west-facing slopes near the coast. Chaparral Three types of chaparral are recognized within the City: southern mixed chaparral, southern maritime chaparral, and chamise chaparral. Southern mixed chaparral is a fire- and drought-adapted community composed of a variety of woody shrubs, many of which are "stump sprouters" that regenerate rapidly from underground undamaged tissues following fires or other ecological perturbation. It is a heterogeneous community type — the dominant shrubs vary from site to site. In most situations the dominants include chamise, interior scrub oak, mission manzanita, laurel sumac, lemonadeberry, and toyon. Understory plants include rush-rose (Helianthemum scopariuni), deerweed (Lotus scoparius), wreathplant (Stephanomeria spp.), and a variety of composites (Asteraceae). Southern maritime chaparral is similar to southern mixed chaparral, but it occurs on sandstone. It is the most limited chaparral type in distribution, particularly in Carlsbad, and is characterized by several endemic shrubs, including Del Mar Manzanita, wart-stemmed ceanothus, coast spice bush, and coastal scrub oak (Quercus dumosa). Other dominant shrubs encountered in this community are the same as those listed above for southern mixed chaparral. Sensitive plant species encountered in southern maritime chaparral include wart-stemmed ceanothus, summer-holly (Comarostaphylis diversifolia var. diversifolia), Del Mar manzanita, ashy spike-moss, and western dichondra (Dichondra occidentalis). Chamise chaparral is a community where chamise is the overwhelming dominant plant. This species may account for over 90 percent of the relative cover. The remaining species include shrubs and understory plants common in other types of chaparral. Chaparral has a patchy distribution throughout the City of Carlsbad, occurring on more mesic north- and west-facing slopes, alternating with coastal sage scrub, grasslands, and oak woodlands. The largest and most representative patches occur immediately east of the Safety Center, southwest of Squires Dam, at the north end of Rancho Santa Fe Road, and along El Camino Real south of Palomar Airport Road. Grassland Both native (perennial) and non-native (annual) grasslands are present within the City of Carlsbad. Native grasslands usually are small in area, frequently occurring as difficult-to-define, open patches of habitat within coastal sage scrub. Many are associated with clayey soils. Native grasslands are characterized by perennial bunch grasses such as needlegrass (Stipa spp.), and a variety of herbaceous annuals and perennials such as Cleveland's shooting star (Dodecatheon clevelandii), blue-eyed grass, fascicled tarweed (Hemizonia fasciculatum), sanicles, and mariposa lily (Calochortus spp.). This habitat type is extremely limited in quantity within the City of Carlsbad, although small patches are distributed throughout many areas of native vegetation. Non-native grasslands occur where native communities have been degraded by repeated fire, grazing or mechanical disturbance, including agriculture. These areas are dominated by a number of non-native grasses, including wild oats (Avena spp.), bromes (Bromus spp.), and others (e.g., Gastridium ventricosum, Vulpia spp.); native grasses are few. Other species present in non-native grasslands include invasive natives such as telegraph weed (Heterotheca grandiflora), fascicled tarweed, doveweed (Eremocarpus setigerus), and weedy introduced species such as Russian-thistle (Salsola australis), black mustard (Brassica nigrd) and 13 tocalote (Centaurea melitensis). Non-native grasslands are best represented in the southeastern corner of the City and south of Palomar Airport Road at the eastern edge of the City. Southern Coastal Salt Marsh Southern coastal salt marsh is a wetland community that develops in low, flat estuaries at the mouths of rivers and streams. Tidal inundation or excessive evaporation results in highly saline conditions around the margins of lagoons, and it is under these conditions that salt marshes develop. This community is characterized by low-growing succulents such as pickleweed, salty susan, salt-cedar, and other halophytic (salt-tolerant) species. Salt marsh communities are highly productive systems that function as nurseries for many species of fish and provide resources for a variety of locally resident and migratory water birds. This community supports a variety of sensitive birds, including Belding's Savannah sparrow, light-footed clapper rail, and California least tern. It also supports one sensitive invertebrate - the salt marsh skipper. Within the City of Carlsbad, salt marsh habitat is present surrounding Batiquitos Lagoon and Agua Hedionda Lagoon, although Batiquitos Lagoon is not open to the ocean. It also occurs in limited amounts around Buena Vista Lagoon and possibly at Loma Alta Creek. Several researchers have described distinct zones within southern coastal salt marsh (e.g., Zedler 1982). Coast and Valley Freshwater Marsh Freshwater marsh occurs in drainages, seepages, and other perennially moist low places. This community is characterized by perennial, emergent monocots (e.g., grasses and lilies), 2-3 m (6-10 feet) tall, such as cattails and bulrushes. Understory species include curly dock, marsh fleabane (Pluchea odorata), and a variety of hydrophytic grasses and herbs. Sensitive plants frequently encountered in the vicinity of this community are spiny rush (Juncus acutus var. sphaerocarpus) and San Diego marsh-elder (Iva hayesiana). Patches of this habitat are present at the upper ends of Buena Vista, Agua Hedionda, and Batiquitos lagoons, where a mixture of plants of salt and freshwater habitats is encountered. Smaller freshwater marshes grow around the perimeter of Lake Calavera and within riparian scrub communities, and may be present in Loma Alta Creek. Sycamore Alluvial Woodland Sycamore alluvial woodland is an open to moderately closed, winter-deciduous, broadleafed riparian woodland, dominated by well-spaced western sycamore. The community typically includes individuals of several other tree species, including willow, coast live oak, Mexican elderberry (Sambucus mexicana), and Fremont cottonwood. This community is best developed in broad channels of intermittent streams, usually with a cobbly substrate. Sycamore alluvial woodland is uncommon in Carlsbad, occurring primarily in the drainage east of the Safety Center and along a narrow drainage south of Lake Calavera. Riparian Scrub As used herein, the term riparian scrub encompasses several natural and semi-disturbed wetland communities, including mulefat scrub, southern willow scrub, and baccharis/tamarisk scrub. These communities occur along river courses and seasonally moist drainages. In Carlsbad, some riparian scrub communities are the result of urban or agricultural run-off. Riparian scrub typically is dominated by willows and Fremont cottonwood, or by mulefat, broom baccharis, or tamarisk (Tamarix sp.), an introduced species. The understory is variable depending upon canopy coverage, disturbance history and water availability, and usually includes poison-oak, desert grape, western ragweed (Ambrosia psilostchya), rushes (Juncus spp.), and a variety of other hydrophytic (wetland) species. Riparian scrub is a highly productive community, contributing to nutrient recycling and the 14 maintenance of water quality, and providing habitat for numerous species. However, locally it supports few sensitive plant and wildlife species. Characteristic well-developed riparian scrub occurs along El Camino Real south of Batiquitos Lagoon, extending east from the mudflats at the eastern end of Agua Hedionda Lagoon (e.g., Macario Canyon), and along the northern portion of the City south of Highway 78 in Buena Vista Creek. Oak Woodland As used herein, oak woodland encompasses several closely related community types, including coast live oak woodland, southern coast live oak riparian forest, and Engelmann oak woodland. Within Carlsbad, this community typically is restricted to mesic north-facing slopes, shaded ravines, and drainages. It is dominated by coast live oak, with scattered individuals of other tree species, including western sycamore, willow, and Mexican elderberry. The understory includes toyon, laurel sumac, California wild rose (Rosa califomicd), poison-oak, and currant (Ribes spp.). Oak woodland is fairly limited in the City of Carlsbad; it is best developed in the drainage behind the Safety Center, both to the north and east. Disturbed Wetland/Floodplain Disturbed wetland or floodplain is not a native plant community. It typically occurs where the natural wetland vegetation has been degraded by mechanical activities or invaded by weedy, non-native species. This habitat is characterized by open and patchy vegetation that includes both native and introduced species. The dominant shrubs include mulefat, broom baccharis, and scattered willow trees. Other species present in varying density include coastal goldenbush (Isocoma veneta), curly dock, castor-bean (Ricinus communis), cockle-bur (Xanthium strumariuni), spiny rush, and pampas grass (Cortaderia spp.). Eucalyptus Woodland Eucalyptus woodland also is a non-native community. It is dominated by various species of planted eucalyptus (Eucalyptus spp.) that survived around old dwellings or in entire groves (e.g., the Hosp Grove). The understory is usually poorly developed or absent owing to the allelopathic (toxic) effect of eucalyptus leaves that acts to inhibit the growth of other plants. Although this habitat supports no sensitive plant or wildlife species, it is often used for nesting by raptors and other birds or roosting by bats. Disturbed Habitat As used herein, the term disturbed habitat encompasses a wide variety of open, non-native habitats that lack permanent structures and currently support activities that prohibit the succession of native plant communities. Four types of disturbed habitat are recognized: (1) typical disturbed habitat; (2) active disturbed habitat; (3) active agriculture; and (4) golf courses. Typical disturbed habitat is characterized by areas that have been graded, scraped, or subject to prior agricultural use. These areas either lack vegetation or support weedy, introduced species such as Russian-thistle, doveweed, Australian saltbush (Atriplex semibaccata), and black mustard. Typical disturbed habitat differs from annual grassland by the abundance or domination of weedy species. For example, fallow agricultural fields often become dominated by species such as Russian-thistle or black mustard. Active disturbed habitat supports mineral extraction or other active uses that inhibit the growth of plants. Active agriculture and golf courses are self explanatory, although what was active agriculture at this writing may appear to be annual grassland or typical disturbed habitat in subsequent years. While these disturbed habitat types directly support few or no sensitive plant and wildlife species, they may be used as foraging habitat by raptors and several mammal species. 15 Developed Developed areas are characterized by structures, parking lots, yards, roads, and a variety of buildings. These areas support no native vegetation. Developed areas occupy the majority of the western half of the City of Carlsbad, but occupy a considerably smaller percentage of the area east of El Camino Real. Open Water Open water is aquatic habitat that lacks vascular vegetation and includes lakes, ponds, reservoirs, and coastal lagoons and may be either fresh, brackish or saline. The area surrounding the open water is almost always characterized by freshwater marsh, salt marsh, or riparian habitats. The largest bodies of open water include the three major coastal lagoons (Batiquitos, Agua Hedionda, and Buena Vista), Lake Calavera, and Squires Dam, although there are a number of artificial ponds throughout the City. 2.2.5 SENSITIVE BIOTA A large number of plant and wildlife species recognized as sensitive, rare, threatened, or endangered by CDFG, USFWS, California Native Plant Society (Smith and Berg 1988), or local resource agencies and conservation groups have been documented from the City of Carlsbad. These are discussed below. Species records come from published sources cited herein, from EIRs and other unpublished environmental documents and technical reports reviewed for the study (see Appendix B), and from personal communications with local biologists familiar with various parts of the City. Sensitive Wildlife Species Birds Several species of birds recognized as threatened or endangered by state or federal agencies occur within Carlsbad as overwintering individuals or resident populations. These include the light-footed clapper rail, Belding's Savannah sparrow, and California least tern, all associated with coastal estuaries and salt marsh habitats. The least Bell's vireo, restricted to riparian woodlands, and the federally- proposed endangered California gnatcatcher, occurring primarily in coastal sage scrub communities below about 1,200 feet (370 m), also have been reported from Carlsbad. The latter species is widespread in coastal sage scrub habitats throughout Carlsbad. Other bird species that occur in Carlsbad that are recognized as sensitive by the resource agencies include the coastal cactus wren, Bell's sage sparrow, southern California rufous-crowned sparrow, California horned lark, and several species of raptors. Accipiter cooperi — Cooper's hawk USFWS: None CDFG: Species of Special Concern Cooper's hawk ranges through most of California and is a common winter migrant in San Diego County. In the county, Cooper's hawk breeds almost exclusively in oak woodland habitats; in the winter they may be found in any woodland habitat (Unitt 1984). Mature trees in suburban areas also may support nesting Cooper's hawks. Populations of this species have declined steadily throughout the state probably as a result of habitat destruction, falconry, and pesticide abuse (Remsen 1979). Riparian areas and groves of mature trees within Carlsbad meet the habitat requirements of this species. 16 Accipiter striatus - sharp-shinned hawk USFWS: None CDFG: Species of Special Concern This species is also a Bureau of Land Management and U.S. Forest Service watchlist species due to declines in populations throughout its breeding range. The sharp-shinned hawk is a regular winter migrant in San Diego County and may be encountered in any woodland habitat (Unitt 1984). Riparian woodlands and suburban areas in Carlsbad represent potential habitat for this species. It was reported from Rancho La Costa. Aimophila ruficeps canescens — Southern California rufous-crowned sparrow USFWS: Candidate (Category 2) CDFG: None The Southern California rufous-crowned sparrow is an uncommon to fairly common resident of San Diego County primarily found in coastal sage scrub that is known to occur in the City of Carlsbad (Unitt 1984). This species recently became a federal candidate for listing as threatened or endangered. Ammodramus sandwichensis beldingi - Belding's Savannah sparrow USFWS: Candidate (Category 2) CDFG: Endangered Belding's Savannah sparrow ranges from Santa Barbara County, California south to about El Rosario, Baja California, Mexico. It is a permanent resident in San Diego County (Unitt 1984). This species nests in salt marshes or the margins of lagoons in low vegetation dominated by pickleweed. Apparently, it prefers the upper littoral zone of tidal marshes, areas flooded only by high spring or storm tides (Massey 1977; Unitt 1984), and it forages in marshes and nearby mudflats, beaches, rocks, and in low coastal strand vegetation. In Carlsbad, Belding's Savannah sparrow has been reported from Batiquitos, Agua Hedionda, and Buena Vista lagoons. Buteo lineatus -- red-shouldered hawk USFWS: None CDFG: None Audubon Society: Blue List, 1972-1986 The red-shouldered hawk is an uncommon to fairly common resident in San Diego County (Unitt 1984). It inhabits nearly the entire county west of the desert. Red-shouldered hawks occupy a variety of woodland habitats, and stands of non-native trees (such as eucalyptus) may serve as breeding habitat. Although concern has been expressed that the numbers of this species are declining, Wilbur (1973) concluded that no major declines in population had occurred in California except possibly in the Sacramento and San Joaquin valleys. These hawks can tolerate human presence if mature trees with a high canopy are maintained; they nest in oak and riparian woodland, suburban areas, and orchards. Campylorhynchus brunneicapillus sandiegensis ~ San Diego (coastal) cactus wren USFWS: Candidate (Category 2) CDFG: Species of Special Concern The cactus wren is a widespread and common species of the southwestern deserts, extending to the Pacific coast in southern California and Baja California. Rea and Weaver (1990) and others previous to them recognize a portion of the coastal population as a separate subspecies, Campylorhynchus 17 brunneicapillus sandiegensis. According to Rea and Weaver, the range of C. b. sandiegensis (the "San Diego cactus wren") is restricted to the coastal slope of San Diego County, extreme southern Orange County, and northwestern Baja California. Populations occurring north of southern Orange County are assigned to the more common and widespread desert subspecies, C. b. anthonyi. Originally, all coastal populations from the Mexican border north to Ventura County had been assigned to the subspecies sandiegensis, but recently it has been concluded that populations in Orange, Los Angeles, and Ventura counties more closely resemble C. b. anthonyi. It should be noted, however, that the American Ornithological Union Committee on Taxonomy and Systematics has not yet accepted the distinction between sandiegensis and anthonyi. Until they do so, sandiegensis should be considered a proposed subspecies. Cactus thickets supporting large populations of the San Diego cactus wren in San Diego County occur primarily in sage scrub and Diegan coastal sage scrub communities, such as those found in the vicinity of San Pasqual, Lake Jennings, Sweetwater Dam, and Otay Mesa. Smaller populations occur at Camp Pendleton, San Elijo and Batiquitos lagoons, and Fletcher Hills. Cactus wrens also recently (ca. 1988) occurred north of Batiquitos and Agua Hedionda lagoons (H. Wier, pers. obs.). The San Diego cactus wren formerly was far more common in the coastal lowlands. Population declines are linked to loss of habitat, and in particular, loss of cholla and prickly-pear cactus thickets (Hix 1990). The San Diego cactus wren currently is being evaluated for possible listing as threatened or endangered by the USFWS. Cathartes aura — turkey vulture USFWS: None CDFG: None Although not recognized as sensitive by the USFWS or the CDFG, the turkey vulture is considered a declining species in San Diego County (Everett 1979). Unitt (1984) reports that this species is a common spring and fall migrant, an uncommon to locally common winter visitor, and a rare to uncommon summer resident in San Diego County. He further states that turkey vultures are widespread throughout the county, particularly over open fields and grasslands. Circus cyaneus hudsonius -- northern harrier USFWS: None CDFG: Species of Special Concern On the national level, the northern harrier has been recognized as sensitive for many years by the National Audubon Society. It ranges throughout California and may be encountered in grasslands, open fields, and salt and freshwater marshes. According to Unitt (1984) the northern harrier is an uncommon to fairly common migrant and winter visitor in San Diego County, and a rare and local summer resident. This species is most common in the coastal lowlands, where as many as 10 (Tijuana River Valley) and 19 (Sweetwater Reservoir) have been observed. Observations of displaying pairs at Las Pulgas Creek and the Santa Margarita River suggest that small numbers of northern harriers still breed on Camp Pendleton. Nests and nesting behavior also have been observed at French Canyon, Sweetwater River, and Dennery Canyon. Elanus caeruleus - black-shouldered kite USFWS: None CDFG: None Although not specifically designated as rare, threatened, or endangered by either CDFG or USFWS, the black-shouldered kite is regarded as a locally sensitive raptor. Formerly the Kelly Ranch north of Agua Hedionda Creek supported a communal roost for approximately 15 to 25 birds (H. Wier, 18 pers. obs.). The black-shouldered kite can nest in riparian woods and large shrubs in coastal sage scrub and chaparral. Empidonax traillii extimus - southwestern willow flycatcher USFWS: Candidate (Category 1) CDFG: None The southwestern willow flycatcher is an uncommon spring and fall migrant found throughout San Diego County (Unitt 1984). Nesting pairs use willow thickets in riparian woodland. There are no records of this species from Carlsbad, but it may occasionally use the same habitat in the City as used by the least Bell's vireo in the past (i.e., Macario Canyon and Buena Vista Creek). Eremophila alpestris actia - California horned lark USFWS: Candidate (Category 2) CDFG: None The California horned lark is a common breeding resident, and an abundant migrant and winter visitor (Unitt 1984). It is commonly found in both native and non-native grasslands, in open agricultural land, and along sandy ocean or bay shores. The horned lark has become a candidate for listing as threatened or endangered, apparently because of rapid development of its habitats. This species is likely to be relatively common in Carlsbad. Lanius ludovicianus — loggerhead shrike USFWS: Candidate (Category 2) CDFG: None The loggerhead shrike is a relatively common resident of San Diego County found around agricultural land, native and non-native grassland, and broken coastal sage scrub and chaparral (Unitt 1984). This small raptor became a federal candidate for listing as threatened or endangered because of rapid development of its habitats. Development not only threatens nesting areas for the shrike, but its prey base as well (including insects, lizards, and small rodents). Pelecanus occidentalis californicus — California brown pelican USFWS: Endangered CDFG: Endangered The California brown pelican is a common to very common non-breeding visitor along the Southern California coast (Unitt 1984). This species was listed as endangered by the state and federal governments as a result of reproductive failures, and consequent precipitous population declines, due to DDT contamination in the 1960s and 1970s. This species is commonly seen along the coast and lagoons in Carlsbad. Phalacrocorax auritus — double-crested cormorant USFWS: None CDFG: None This species is a common non-breeding visitor in San Diego County (Unitt 1984). It is observed most frequently on bays, lagoons, and estuaries along the coast (Unitt 1984), but also may be encountered on ponds at inland localities. Everett (1979) considers the double-creasted cormorant as a "declining" species in San Diego County. He indicates that it formerly bred at Lake Henshaw, but has not 19 nested in the county since about 1933. This species occurs at Agua Hedionda, Buena Vista, and Batiquitos lagoons, and likely uses larger inland lakes as well. Polioptila califomica — California gnatcatcher USFWS: Proposed endangered CDFG: None The California gnatcatcher is a small gray non-migratory bird with a black tail with white edges. In the breeding season the male has a black cap. It eats insects and builds a small, cup-shaped nest of plant material, animal hair, and spider webs. The present known range of the California gnatcatcher extends from an isolated population on the Palos Verdes Peninsula of Los Angeles County, and southern Orange, western Riverside, and San Diego counties, into northern Baja California, Mexico. It is an obligate resident of coastal sage scrub and Riversidean (inland) sage scrub communities, although it may use adjacent disturbed, chaparral, and riparian habitats. Individuals of this species are generally found at elevations below 800 feet along the coast, and below 1600 feet in Riverside County (Atwood 1990). Based on average territory size and available habitat, Atwood (1990) estimated that 1,200-2,000 pairs were resident within the state in 1990. A pair of gnatcatchers may forage over 6 to 45 acres of land during the breeding season (generally the end of July to the end of June), and may forage more widely at the end that period. In Carlsbad, gnatcatcher territories probably are less than 20 acres due to the coastal location and constrained condition of most of the suitable habitat locations (Mock 1992). The California gnatcatcher has no special status with the CDFG, although it formerly was listed (as Polioptila melanura) as a second priority "Species of Special Concern." The USFWS has proposed endangered status for the California gnatcatcher pursuant to the Endangered Species Act of 1973. Although a decision by the USFWS on the status of the gnatcatcher originally was due in September of 1992, the "final rule" probably will not be issued until January 1993. In San Diego County, gnatcatcher populations are known from several sites along the coast and from as far inland as San Pasqual, Poway, Lakeside, Escondido and Ramona. The California gnatcatcher is widespread throughout the coastal sage scrub areas of Carlsbad. The largest populations are concentrated in the northeastern and southeastern portions of the City. Rallus longirostris levipes -- light-footed clapper rail USFWS: Endangered CDFG: Endangered This subspecies ranges from about Santa Barbara south into northern Baja California, Mexico (Unitt 1984). In San Diego County, it is an uncommon and very localized resident of tidal salt marshes that support large stands of cord grass (Spartina foliosa) (Unitt 1984). It may also occur in brackish marshes dominated by cattails. The status of the clapper rail in San Diego County has been monitored closely since about 1973 by P. Jorgensen (Wilbur 1974; Wilbur et al. 1979) and the USFWS. Clapper rails formerly were much more common in the County. Its range and numbers have been reduced greatly by destruction and degradation of salt marsh habitats. Census results from 1973 through 1981 indicate that the total San Diego County population size fluctuates between about 55 and 75 pairs; the total population in California was 173 pairs in 1981 (Unitt 1984). In Carlsbad, the light-footed clapper rail has small populations, but it has been reported from Batiquitos, Agua Hedionda, and Buena Vista lagoons. 20 Sterna antillarum browni — California least tern USFWS: Endangered CDFG: Endangered The California least tern is a common, but very localized, summer resident and migrant in San Diego County (Unitt 1984). This species nests colonially along the coast on barrier dunes at river mouths, lagoon entrances, and along sandy strips. Within Carlsbad, the least tern has nested at the Agua Hedionda, Batiquitos, and Buena Vista lagoons in the past (Unitt 1984). Threats to this species come from development of suitable nesting areas. This forces the least tern to use fewer nesting areas, thus increasing the risk of whole colony failure due to local predation and other disturbances. Vireo bellii pusillus — least Bell's vireo USFWS: Endangered CDFG: Endangered Least Bell's vireo is a small, gray and white, migratory songbird that inhabits willow-dominated riparian areas of southern California and adjacent northern Baja California, Mexico (San Diego Association of Governments 1988). It is one of four North American subspecies of Bell's vireo. Historically, this subspecies was abundant in riverine habitats from Baja California to Tehama County in central California (Grinnell and Miller 1944; Willett 1933), with the center of its breeding range in the Sacramento and San Joaquin Valleys. Widespread destruction of its obligate riparian habitat for agricultural use, livestock grazing, flood control, urban development, and various commercial uses, in combination with increased brood parasitism by the exotic brown-headed cowbird (Molothrus ater), decimated vireo numbers, extirpating it from the central valleys, and restricting the species to small, fragmented populations in a fraction of its former range (USFWS 1988). By 1985, only 285 pairs were known from 45 locations in 9 counties (USFWS 1988). In response to the unparalleled decline of this passerine, the least Bell's vireo was listed as endangered by the CDFG in 1980, and by the USFWS in May 1986. The two Carlsbad records of which we are aware are males from Macario Canyon (feeding a fledgling in 1987) and Buena Vista Creek (H. Wier, pers. obs. circa 1983). Reptiles and Amphibians Reptiles documented from Carlsbad that are recognized as federal Category 2 candidates for listing as threatened or endangered by the USFWS or as Species of Special Concern by CDFG include San Diego horned lizard, orange-throated whiptail, western whiptail, and northern red diamond rattlesnake. Other sensitive reptiles likely to be present include two-striped garter snake, and southwestern pond turtle. The western spade-foot toad, recognized as a Species of Special Concern by CDFG, also has been recorded from the City. Cnemidophorus hyperythrus beldingi — orange-throated whiptail USFWS: Candidate (Category 2) CDFG: Species of Special Concern The orange-throated whiptail is a small, slender, insectivorous lizard with a bright orange patch on its throat. It occurs in the United States and Mexico, ranging from southern California (west of the transverse and peninsular ranges) south to about mid-way through the peninsula of Baja California. This species has exhibited population declines in California associated with the conversion of coastal sage scrub and dry wash habitats for agriculture, urban development, and flood control. An active forager, the orange-throated whiptail frequents dry, often rocky hillsides, ridges, valleys, and washes that support broken coastal sage scrub, chaparral, mule fat scrub, and grassland mixed with sage scrub 21 species. It often occurs with the more common western whiptail (C. tigris). The orange-throated whiptail relies to some extent on the burrows of small mammals, such as the California ground squirrel (Spermophilus beecheyi), for protection from predators and adverse environmental conditions. This species was recorded on the Alanda project site located near El Camino Real in the northeastern portion of the City, and from an area located south of Palomar Airport Road and west of El Camino Real. Cnemidophorus tigris multiscutatus - coastal whiptail USFWS: Candidate (Category 2) CDFG: None The coastal whiptail is an active lizard that inhabits sparse coastal sage scrub habitat that provides room for running (Stebbins 1985). This species avoids dense shrub vegetation and grasslands. It was recently added to the candidate species list because of threats to its habitat by development. The coastal whiptail is likely to occur on more open, drier south-facing slopes in Carlsbad. Crotalus ruber — northern red-diamond rattlesnake USFWS: Candidate (Category 2) CDFG: None The northern red-diamond rattlesnake inhabits coastal sage scrub, chaparral, and open woodlands (Stebbins 1975). This species is relatively common in the coastal sage scrub community in San Diego County. However, it was added to the federal candidate list because of threats to its habitat by development. This species is highly likely to occur in the City of Carlsbad. Phyrnosoma coronatum blainvillei ~ San Diego horned lizard USFWS: Candidate (Category 2) CDFG: Species of Special Concern The San Diego horned lizard is a small, spiny, somewhat rounded lizard that occurs primarily in open areas in coastal sage scrub communities. It was a common species in San Diego County until about 10 years ago (Hix 1990). Three factors have contributed to its decline: loss of habitat, over collecting, and the introduction of exotic ants. In some places, especially adjacent to urban areas, the introduced ants have displaced the native species upon which the lizard feeds. This species has been recorded in the northeastern part of the City just west of Lake Calavera and to the northeast of Agua Hedionda Lagoon. Thamnophis hammondi - two-striped garter snake USFWS: Candidate (Category 2) CDFG: None Although it currently receives no state or federal protection, the two-striped garter snake is recognized as a threatened species by the San Diego Herpetological Society (McGurty 1980). It occurs primarily in wetlands, particularly freshwater marsh and riparian scrub habitats. Although it has not been reported from Carlsbad, it is likely to be resident. Scaphiopus hammondi -- western spade-foot toad USFWS: None CDFG: Species of Special Concern The western spade-foot toad is primarily a species of the lowlands, frequenting washes, floodplains of rivers, alluvial fans, alkali flats (Stebbins 1985), temporary ponds, and vernal pools. It is considered 22 sensitive because of declines in populations associated with loss of habitat. This species has been reported from the Woolley project. Mammals No mammal species presently known to occur in the City are recognized as threatened or endangered by the USFWS or CDFG. Five federal Category 2 candidate species are highly likely to occur in Carlsbad: the San Diego black-tailed jackrabbit, San Diego desert woodrat, southern grasshopper mouse, Dulzura California pocket mouse, and northwestern San Diego pocket mouse. Three other mammal species recognized as federal Category 2 candidates for listing as threatened or endangered have a remote chance of occurring at least occasionally in Carlsbad. These include the Pacific pocket mouse, California mastiff bat (Eumops perotis califomicus), and spotted bat (Euderma maculatum). The Pacific pocket mouse has been recorded near the coast in the City of Oceanside but otherwise is extremely rare within its historic range (Bond 1977). None of the bat species has been recorded in Carlsbad, and there are relatively few suitable roosting sites for bats within the City limits. The California mastiff bat, which has been recorded from near Lake Hodges, and the spotted bat both require rugged, rocky areas with crevices for roosting. Both of the bats could occur in the City during foraging bouts to take advantage of insects around agriculture and wetland areas or to utilize waters at lakes, streams, or swimming pools. In contrast to our knowledge of the distribution of plant and bird species, the status of many mammals is poorly known. Most mammals are secretive and nocturnal or crepuscular (active around dusk or twilight) and are not readily identifiable unless captured and examined close at hand. There has been much less field work on the occurrence and distribution of mammals in the City of Carlsbad, particularly small mammals and bats. Lepus califomicus bennettii — San Diego black-tailed jackrabbit USFWS: Candidate (Category 2) CDFG: None The San Diego black-tailed jackrabbit is found in open sage scrub habitat and grassland. It was recently added to the federal candidate list because of threats to its habitat by development. In San Diego County, it is known from San Marcos, Escondido, San Diego area, Jamul Creek, and the Laguna Mountains (Bond 1977). It is highly likely to occur in Carlsbad. Neotoma lepida intermedia — San Diego desert woodrat USFWS: Candidate (Category 2) CDFG: None The San Diego desert woodrat inhabits areas with heavy growth, such as dense coastal sage scrub, chaparral, cactus, or rock crevices. This species was recently added to the federal candidate list because of threats to its habitat from development. In San Diego County, it is known from the Bonsall, Mission San Luis Rey, Mission Gorge, Murphy Canyon, Murray Dam, and San Diego areas (Bond 1977). Despite no collections specifically from the City of Carlsbad, these records essentially surround the City and, thus, the species is likely to occur there. Onychomys torridus ramona - southern grasshopper mouse USFWS: Candidate (Category 2) CDFG: None The southern grasshopper mouse is a stout mouse with a relatively short and thick tail. This species primarily feeds on insects, but is known to capture and devour other rodents. Grasshopper mice are 23 interesting in that they emit audible "howls" upon leaving their day burrows. The grasshopper mouse is relatively uncommon throughout its range compared to other rodent species such as deer mice (Peromyscus spp.). O. t. ramona is found in the lower and upper Sonoran life zones of the Pacific slopes, and in San Diego County has been recorded from Carlsbad, Gulp Valley, Dulzura, San Diego, San Pasqual Valley, and Tijuana River Valley (Bond 1977). Continued urbanization of the coastal region threatens the existence of this subspecies. Perognathus (Chaetodipus) califomicus femoralis - Dulzura California pocket mouse USFWS: Candidate (Category 2) CDFG: None The Dulzura California pocket mouse typically is found on slopes dominated by chaparral or oaks. It is a relatively common pocket mouse within its preferred habitat. It was given candidate status apparently because of rapid depletion of its habitat in Southern California. In San Diego County, this species has been recorded from Banner, Campo, Dehesa, Dulzura, Escondido, Pala, Rainbow, Ramona, Palomar Mountain, San Marcos, Santee, Santa Ysabel, and Witch Creek (Bond (1977). Because of the proximity of these records to Carlsbad (e.g., San Marcos), the Dulzura California pocket mouse is almost certainly an inhabitant of the City. Perognathus (Chaetodipus) fallax -- northwestern San Diego pocket mouse USFWS: Candidate (Category 2) CDFG: None The northwestern San Diego pocket mouse inhabits sparse or disturbed coastal sage scrub or grasslands with sandy soils. This species was recently added to the federal candidate list because of threats to its habitat by development. In San Diego County, it is known from Del Mar, Dulzura, Jacumba, Lake Hodges, Pala, San Diego area, and San Marcos (Bond 1977). Although these collection localities do not specifically include Carlsbad, they surround it and, thus, the species is highly likely to occur in the City of Carlsbad. Invertebrates Four species of butterflies that are resident or potentially resident within the City of Carlsbad are recognized as federal Category 2 candidates for listing as threatened and endangered: Harbison's dun skipper, salt marsh skipper, Hermes copper, and quino checkerspot. Although only the salt marsh skipper has been documented from Carlsbad, Harbison's dun skipper and Hermes copper are highly likely residents. Both are host specific insects and usually are encountered wherever their larval foodplants occur. The larvae of Harbison's dun skipper feeds exclusively on San Diego sedge (Carex spissa), which has been reported from several oak woodland and riparian areas within the City. The larvae of Hermes copper feed on redberry (Rhamnus crocea), which is a common species throughout much of the chaparral in the City. In addition to these sensitive butterflies, the federal Category 2 candidate globose dune beetle, a resident of coastal dunes, may be present in small remnants of dunes along the coastal margins of the City. Euphyes vestris harbisoni - Harbison's dun skipper USFWS: Candidate (Category 2) CDFG: None Harbison's dun skipper is a medium-small, chocolate brown butterfly restricted to riparian habitats where its larval host, San Diego sedge (Carex spissa), grows. It occurs in a series of scattered and disjunct colonies throughout western San Diego County, extending as far north as the Santa Ana Mountains of Orange County (Brown and McGuire 1983). The insect is single brooded (one 24 generation per year); the flight period extends from late May to early July. Several instances of extirpation are documented for populations of Euphyes vestris in San Diego County. Wherever Carex spissa is found, Harbison's dun skipper also is likely to be present. Carex spissa has been documented rrom several riparian areas within Carlsbad. The most likely Carlsbad locale supporting a population of the Harbison's dun skipper is the riparian scrub habitat along El Camino Real in the Evans Point area. Panoquina errans - salt marsh skipper USWFS: Candidate (Category 2) CDFG: None The salt marsh skipper is restricted to the narrow coastal margin from about Santa Barbara County south to the southern tip of Baja California, Mexico (MacNeill 1962; Donahue 1975). It is represented by a series of disjunct and isolated populations confined to coastal estuarine or salt marsh habitats. The single larval host is salt grass (Distichlis spicata) with which adults are commonly associated (Emmel and Emmel 1973; Brown 1981). Owing to the apparently tolerant and invasive nature of salt grass, some colonies of the salt marsh skipper have managed to persist despite limited habitat alteration. Nectar sources for the skipper include heliotrope (Heliotropum cutvassavicum), salty susan, sea rocket, deerweed, and frankenia (Frankenia salind) (Brown 1981; Busnardo 1989). The flight period of the salt marsh skipper extends from March or April to October in most years, in a series of overlapping generations. Population density reaches its highest in mid-to-late summer. The salt marsh skipper is resident in several protected areas in Southern California. Because of the reduction in acreage of the salt marsh habitat in southern California, the salt marsh skipper is considered highly sensitive. Populations of the skipper are disappearing rapidly in Baja California as coastal marshes are being altered for salt production and other developments. The salt marsh skipper has been observed at the east end of Agua Hedionda Lagoon, and it is likely to be resident in salt marsh habitats around Batiquitos and Buena Vista lagoons. Sensitive Plant Species Within the City of Carlsbad, 20 species of plants recognized as regionally sensitive by the California Native Plant Society (Smith and Berg 1988) have been detected. These species are discussed below. Acanthomintha ilicifolia — San Diego thorn-mint USFWS: Candidate (Category 1) CDFG: Endangered CNPS: List IB, 3-3-2 San Diego thorn-mint is an aromatic, spring-blooming (April-May) annual, 0.5-1.5 dm tall. The flowers occur in whorls that are subtended by several bracts armed with needlelike spines ~ thus, the name "thorn-mint". It is restricted in distribution to San Diego County and adjacent Baja California, Mexico. San Diego thorn-mint occurs on clay lenses of several geologic origins on mesas and slopes below 500 m (1,600 ft) elevation and is associated with Diegan coastal sage scrub, chaparral, and native grassland. In San Diego County, the species is known from Encinitas and San Marcos south to Sweetwater and Otay Lakes (Beauchamp 1986). The species also is known from the higher elevations of McGinty Mountain and Poser Mountain. Reported from the Woolley Annexation Project, the Carlsbad Land Investors project, and Camino Hills Mobile Home Park project. 25 Adolphia califomica — California adolphia USFWS: None CDFG: None CNPS: List 2, 1-2-1 California adolphia is a moderate-sized (0.5-1.0 m) profusely branched, rigid, spiny shrub, ranging from western San Diego County, California, south into adjacent northwestern Baja California, Mexico (Wiggins 1980). It generally occurs on clay soils in dry canyons and on hillsides on south-facing slopes and washes in chaparral and coastal sage scrub communities below 300 m (965 ft) elevation. It blooms in early winter to spring (December-May). In San Diego County it has been reported from Morro Hill, Cerro de Calavera, Agua Hedionda, Rancho Santa Fe, Mount Soledad, Bernardo, Chollas Valley, Barrett Junction, and Proctor Valley (Beauchamp 1986). This species is threatened by urbanization, which has reduced considerably its former range (Smith and Berg 1988). The California adolphia has been reported from numerous localities in the City, including Arroyo La Costa, Airport Business Center, Santa Fe Glens, La Costa Northeast Annexation, Woolley Annexation Project, Carlsbad Highlands, the east end of Dove Lane, western portion of Rancheros, Rancho Carrillo, Lake Calavera, Evans Point, Camino Hills Mobile Home Park, and others. Arctostaphylos glandulosa ssp. crassifolia - Del Mar manzanita USFWS: Candidate (Category 2) CDFG: None CNPS: List IB (Reinstated, see below) Del Mar manzanita represents the coastal form of San Diego County's common burl-forming manzanita, and it is one of several sensitive plants that are indicators of the unique and depleted southern maritime chaparral habitat. Because of taxonomic difficulties, the California Native Plant Society (Smith and Berg 1988) and the California Natural Diversity Data Base previously did not recognize this taxon as sensitive. In a recent treatment of Arctostaphylos, Wells (1990) considers ssp. crassifolia as a valid taxon representing those populations in coastal San Diego County and adjacent northern Baja California (Munz 1974). CNPS botanist Mark Skinner has proposed to reinstate Del Mar manzanita as a List IB species. This species was reported from Arroyo La Costa and Rancho Carrillo, and a few others. Artemisia palmeri - San Diego sagewort USFWS: None CDFG: None CNPS: List 2, 2-2-1 San Diego sagewort is a summer-blooming (July-September) weak shrub with long (0.5-0.8 m) wandlike stems (Munz 1974). It is restricted in distribution to San Diego County and Baja California. It typically occurs at low elevations (below 660 m) along intermittent streams and arroyos. In San Diego County it has been recorded from Ramona, Mt. Woodson, Del Dios, Poway, and at several sites from Tecolote Canyon south to the international border and east to Jamul (Beauchamp 1986). In Carlsbad this species is common in a drainage surrounded by chaparral adjacent to El Camino Real, south of Palomar Airport Road. 26 Brodiaea filifolia — thread-leaved brodiaea USFWS: Candidate (Category 2) CDFG: Endangered Thread-leaved brodiaea is a rare, herbaceous, spring-blooming (May-June) perennial, with few grasslike leaves and violet flowers. It grows in heavy clay soils that form open areas in coastal sage scrub and chaparral communities below about 600 m (2,000 ft). It is found primarily in grassland and vernal pool habitats. In San Diego, thread-leaved brodiaea is known from Alta Loma Creek, Vista, Thibodo Ranch, Buena, San Marcos Hills, and Agua Hedionda (Beauchamp 1986). This species was reported from the Camino Hills Mobile Home Park project and west of Calavera Hills, and has been the subject of a revegetation program at the Camino Hills site. Brodiaea orcuttii -- Orcutt's brodiaea USFWS: Candidate (Category 2) CDFG: None CNPS: List IB, 1-3-2 Orcutt's brodiaea is a herbaceous, spring-blooming (April-July) perennial that grows from a corm. It is found only in San Diego County, the Santa Rosa Plateau in Riverside County and northern Baja California, Mexico (Wiggins 1980). It occurs in association with vernal pools, streams, and seeps. In San Diego County, the species occurs infrequently in coastal and foothill regions below 1,500 m (4,827 ft) elevation. Reported localities include the Santa Margarita Mountains, San Marcos, Poway, Henshaw Dam, Santa Ysabel, Cuyamaca Mountains, Miramar Naval Air Station, Ramona, Buschalaugh Canyon, Japatual Valley, Woodwardia Canyon, Cedar Canyon, Otay Mountain, Tecate Mountain and lower Otay Reservoir (Beauchamp 1986). This species was reported from Arroyo La Costa. Ceanothus verrucosus — wart-stemmed ceanothus USFWS: Candidate (Category 2) CDFG: None CNPS: List 2, 1-2-1 Wart-stemmed ceanothus is an erect, stiff-branched, rounded, evergreen shrub, 1.0-3.0 m tall, that occurs on dry hills and mesas in coastal and mixed chaparral habitats below 300 m (965 ft) in western San Diego County and adjacent Baja California, Mexico. It is a spring-blooming species, flowering from January to April (Munz 1974). Beauchamp (1986) reports this species from Agua Hedionda, Encinitas, Leucadia, Torrey Pines State Reserve, Kearny Mesa, Lake Hodges, and Point Loma. In Baja California wart-stemmed ceanothus ranges from the Pacific coast to the foothills of the Sierra Juarez and Sierra San Pedro Martir (Wiggins 1980). This species was reported from several areas in the City, including Arroyo La Costa, Rancho La Costa, and the south end of Batiquitos Drive. Comarostaphylis diversifolia ssp. diversifolia — summer-holly USFWS: Candidate (Category 2) CDFG: None CNPS: List IB, 2-2-2 Summer-holly is a large shrub generally occurring on north-facing canyons and slopes and in sandy washes in chaparral and foothill habitats below 700 m (2,297 ft) in scattered locations from the Pacific coast in San Diego County south into Baja California. Reported localities in the County include San Marcos Mountains, Mount Whitney, Rancho Santa Fe, Gonzales Canyon, Encinitas, Mount Soledad, Penasquitos Canyon, Del Mar Heights, Iron Mountain, canyons of Mission Valley, Jamul Valley, and 27 Otay Mountain (Beauchamp 1986). This species was reported from Arroyo La Costa, the Airport Business Center, and Rancho Carrillo. Corethrogyne filaginifolia var. linifolia - Del Mar Mesa sand aster USFWS: Category 2 (candidate) CDFG: None CNPS: List IB, 3-2-3 The Del Mar Mesa sand aster is a slender, erect, summer-flowering (July-September), perennial herb, 0.2-0.4 m in height, with narrow, linear leaves. This species is endemic to coastal San Diego County, California. Although Munz (1974) indicates that it is common on bluffs and brushy slopes near the sea in Diegan coastal sage scrub and chaparral, Beauchamp (1986) indicates that it is occasional in sandy and disturbed places below 150 m (480 ft), and only along the coast. Beauchamp (1986) records it from Carlsbad, Encinitas, Del Mar, Del Mar Heights, and Torrey Pines State Reserve. Beauchamp (1986) also lists two localities that are unlikely and should be verified (J. C. Dice, pers. comm.): Fort Rosecrans and San Diego Bay. These specimens probably are C. f. var. incana. It is likely that Del Mar Mesa sand aster has been extirpated from some of these historical localities. According to Smith and Berg (1988), as a component of maritime chaparral, Del Mar Mesa sand aster is threatened by development. Dichondra occidental^ — western dichondra, western pony foot USFWS: Candidate (Category 3C) CDFG: None CNPS: List 4, 1-2-1 Western dichondra is a low perennial herb generally occurring on dry slopes, often as an understory plant, in Diegan coastal sage scrub and chaparral. It often proliferates on recently burned slopes. The species is found in coastal San Diego and Orange counties, on some of the Channel Islands, and in northern Baja California, Mexico. In San Diego County, western dichondra is encountered frequently in intact vegetation from Del Mar to Agua Hedionda, south to the international border. Because of its fairly wide distribution and relative abundance in San Diego County and elsewhere, this species is not particularly sensitive. This species was reported from Airport Business Center, Evans Point, and Carlsbad Highlands. Eryngium aristulatum var. parishii — San Diego button-celery USFWS: Candidate (Category 1) CDFG: Endangered CNPS: List IB, 1-3-2 San Diego button-celery is a prostrate or decumbent (lying down) biennial or perennial species that occurs in or near vernal pools in Riverside and San Diego counties and in northern Baja California, Mexico. It blooms from March through July. In San Diego County it has been recorded from Camp Pendleton, San Marcos, Miramar Naval Air Station, Clairemont Mesa, College Grove, and Otay Mesa (Beauchamp 1986). The high sensitivity rating, combined with the limited habitat occupied by this species, make it a vulnerable and important resource. In Carlsbad, San Diego button-celery was reported in a vacant field south of the Carlsbad Sewage Treatment Plant adjacent to Interstate 5 (C. Rieser, pers. comm.). 28 Euphorbia misera — cliff spurge USFWS: None CDFG: None CNPS: List 2, 2-2-1 Cliff spurge is a moderately large (0.3-1.0 m) irregularly branched shrub that occurs along sea bluffs and in coastal sage scrub. This species is distributed from Orange and Riverside counties, California, to Baja California, Mexico, and on San Clemente and Santa Catalina Islands. In San Diego County, cliff spurge occurs from about Carlsbad south to the international border. It is relatively common, but extremely local in southwestern San Diego County. In adjacent Baja California, it extends south almost to the 28th parallel (Wiggins 1980). Cliff spurge is known from one locality in Carlsbad -- a small patch of maritime succulent scrub north of Windsong Shores. Fritillaria biflora — chocolate lily or mission bells USFWS: None CDFG: None CNPS: Considered, but rejected: Too common Chocolate lily is a small herbaceous perennial, 15-40 cm in height, with large, nodding, dark brown to greenish purple, bell-shaped flowers. It is in bloom from about January through April. Chocolate lily is occasional on open slopes with clay soils in native grassland and sparse coastal sage scrub communities below about 700 m (2,297 ft). It ranges from San Diego and Riverside counties north to Mendocino County (Munz 1974). In San Diego County it has been recorded from upper San Onofre Canyon, San Marcos, Rancho Santa Fe, Bernardo, Del Mar, San Diego, Point Loma, Dehesa, McGinty Mountain, Santee, and several other localities (Beauchamp 1986). Although the chocolate lily has a relatively broad distribution in coastal California, the fact that it is restricted to native grasslands, a rare and depleted habitat, suggests that it should be considered a sensitive species. In Carlsbad, this species has been reported from Bressi Ranch (south of Palomar Road/east of El Camino Real). Harpagonella palmeri var. palmeri - Palmer's grappling-hook USFWS: None CDFG: None CNPS: List 2, 1-2-1 This widely-distributed, diminutive annual occurs in Los Angeles, Orange, Riverside, and San Diego counties, and also on San Clemente Island, in Arizona, in Baja California, and in Sonora, Mexico. It typically grows on clay soils and burns below 1,000 m (3,280 ft) elevation, and flowers from February to April (Munz 1974; Wiggins, 1980; Beauchamp 1986). In San Diego County, Palmer's grappling hook is reported in Guajome Mesa, Rancho Santa Fe, Olivenhain, Poway Grade, Kearny Mesa, Emerald Hills, Mission Gorge, Otay, Dehesa, Rice Canyon, Table Mountain, and Box Canyon (Beauchamp 1986). This species was reported from Calavera Hills. Iva hayesiana -- San Diego marsh-elder, poverty weed USFWS: Candidate (Category 2) CDFG: None CNPS: List 2, 2-2-1 This low perennial shrub occurs in southwestern San Diego County and northern Baja California (Munz 1974; Smith and Berg 1988). It grows in low-lying, moist or alkaline places along intermittent 29 streams in coastal areas. Although it has a fairly restricted range in San Diego County, San Diego marsh-elder is apparently more widespread to the south, ranging into central Baja California (Wiggins 1980). San Diego marsh-elder often grows in association with spiny rush and other indicators of wetland habitat (Reed 1988). San Diego marsh-elder may be a dominant understory plant in disturbed floodplain situations such as that in the Otay River Valley. Its habitat in southwestern San Diego County is threatened by coastal development and channelization of local streams and rivers. Muilla clevelandii — San Diego golden-star USFWS: Candidate (Category 2) CDFG: None CNPS: List IB, 2-2-2 San Diego golden-star is found only in southern San Diego County and adjacent northwestern Baja California, Mexico. This spring-blooming (March-May), herbaceous perennial occurs infrequently on clay soils on dry mesas and hillsides and among vernal pools in Diegan coastal sage scrub or chaparral. Primary threats to this species are illegal dumping, off-road vehicle activity, and urbanization (Smith and Berg 1988). A survey of herbarium specimens collected in the past century and deposited at the San Diego Natural History Museum indicates that few previous localities for this plant still exist in an undeveloped state or condition otherwise suitable for supporting populations of this plant. Extant populations include those in vernal pool habitats on Naval Air Station Miramar, west of Rancho Bernardo, and San Ysidro Mountains. In Carlsbad, large populations occur on the Rancheros property and south of Rancho Santa Fe Road. Juncus acutus var. sphaerocarpus - spiny rush USFWS: None CDFG: None CNPS: List 4, 1-1-3 This large (0.5-1.5 m), tufted, perennial rush, with stout, rigid stems, is encountered frequently in alkaline seeps and marshes or in areas adjacent to these. Spiny rush has a wide distribution from San Luis Obispo County south to Baja California and east to Imperial County and Arizona, although some doubt exists regarding the taxonomy of eastern populations. Although urbanization represents a serious threat to spiny rush (Smith and Berg 1988), the abundance of this plant in many widely separated wetlands, together with the current application of protection for these habitats, indicates a rather low threat to this species. This species was reported from the La Costa Development, Batiquitos Pointe Site, west side of Batiquitos Lagoon, Lake Calavera, Buena Vista, Evans Point, Buena Vista Creek, and other locations. Quercus engelmannii -- Engelmann oak USFWS: None CDFG: None CNPS: List 4, 1-2-2 Engelmann oak is a moderately large tree with gray-green foliage, whitish and shallowy furrowed bark, and an open, airy appearance. It generally occurs on mesas and open slopes in foothill and coastal areas below about 1,300 m (4,200 ft), in San Diego, Riverside, and Orange counties and northern Baja California. It may occur in closed canopy riparian woodlands dominated by coast live oak or in more monotypic stands as an oak savanna on moist north-facing slopes. This oak occupies the smallest range of any oak tree in the southwestern United States (Scott 1990); the center of its distribution is cismontane San Diego County. Engelmann oaks are sensitive to land management practices such as fire, and their small, disjunct woodlands are highly susceptible to extirpation. Individual trees typically live from 50 to 80 years; however, a few trees in every woodland may be 150 30 to 350 years old (Scott 1990). This species was recorded from the woodland areas south of Palomar Airport Road west of El Camino Real (SW Quad). Selaginella cinerascens — ashy spike-moss or mesa clubmoss USFWS: None CDFG: None CNPS: List 4, 1-2-1 This tiny, prostrate, whitish gray, moss-like plant occurs in San Diego County and adjacent northwestern Baja California, Mexico. In San Diego County it ranges from about Rancho Bernardo south to the international border. It is relatively abundant in coastal areas, occurring on flat mesas below 300 m (965 ft), that are prime locations for housing. Development of these areas has caused massive reduction of the habitat of the ashy spike-moss. Although this plant is one of the most common understory plants in Diegan coastal sage scrub and coastal chaparral communities, its extremely restricted geographical range and the rapid disappearance of its primary habitats combine to make it a sensitive resource. This species was reported from Arroyo La Costa, Airport Business Center, Woolley Annexation Project, Carlsbad Highlands, western side of Rancheros, intersection (NW) of Alga Road and El Camino Real, north of N end of Ambrosia Lane, Rancho Carrillo, and Evans Point. Solarium tenuilobatum — narrow-leaved nightshade USFWS: Candidate (Category 2) CDFG: None CNPS: List IB, 3-1-3 This purple-flowered, low, woody shrub occurs infrequently between 200 and 1,100 m (656 to 3,610 ft) elevation in chaparral habitats in southern San Diego County and Baja California. It is known from Jamul, Lyons Valley, Otay Mountain, Potrero Grade, Barrett Dam, Silverwood, Campo (Beauchamp 1986), the east slope of San Miguel Mountain (PSBS 1980), the eastern end of the Sweetwater River Valley, and near Mussey Grade Road near Ramona (F. T. Sproul, pers. comm.). This species was reported from Carlsbad Highlands. Other Key Species In addition to sensitive wildlife and plant species, there also are several key wildlife species whose presence in Carlsbad reflect the overall health and viability of the City's natural resources. A sample of these species includes mule deer (Odocoileus hemionus), bobcat (Felis rufus), gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), and golden eagle (Aquila chrysaetos). The conservation program and preserve system developed by the City should consider the requirements of these species as well. 31 SEC! ON 3 Resource Inventory and Mapping BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 3 RESOURCE INVENTORY AND MAPPING 3.1 INTRODUCTION The resource analysis for the HMP focused on two major biological tasks: (1) accumulation of a biological inventory and mapping of habitats and sensitive species present within the City of Carlsbad; and (2) identification of a potential interconnected preserve system to accommodate both relatively common and sensitive biological resources. This section details the methods and results of the first task. The second task included analyses of habitat value and habitat sensitivity, which are described in detail in Section 4. The study focused on undeveloped areas within Carlsbad, with particular emphasis on large and/or connected areas of undisturbed native habitat. The majority of the data for the biological resource analysis was obtained by reviewing environmental documents, topographic maps, and aerial photographs made available through the City of Carlsbad, resource agencies, and landowners/ developers. A limited amount of field surveys were conducted to check the accuracy of the mapping efforts. Data from areas immediately adjacent to the City of Carlsbad (i.e., Encinitas and San Marcos) also were reviewed, because of their relevance to establishing wildlife corridors and habitat linkages to offsite open space areas. 3.2 MATERIALS Data for the biological inventory and mapping effort were obtained from a variety of sources. The primary source of data was the library of the City of Carlsbad, which includes over 50 biological resources reports from EIRs and other environmental documents for projects proposed within the City from 1978 to present (see Appendix B). Because the reports represent a variety of proposed developments, have been written by a variety of biologists, and cover a wide range of years, they are highly variable in their thoroughness and coverage. Most of the reports include vegetation maps, locations of sensitive species, lists of plant and wildlife species observed, and descriptions of habitat types. Additional data regarding sensitive species and habitats present within the City of Carlsbad were obtained from the California Natural Diversity Data Base (CNDDB) (USGS quadrangles San Luis Rey, San Marcos, Encinitas, and Rancho Santa Fe), the California Native Plant Society's Inventory of Rare and Endangered Vascular Plants (Smith and Berg 1988), Report on the California Butterflies Listed as Candidates for Endangered Status by the USFWS (Murphy 1990), Beauchamp (1986), discussions with local experts, and available information regarding the distribution of vernal pools in San Diego County (Bauder 1986). Other materials consulted included soil maps from Bowman (1973), a 7.5' x 7.5', 500-scale (1"=500') color aerial photograph of the City (Aerial Fotobank, Inc., 6 February 1988), and a set of 23 400- scale (1"=400') blueline aerial orthophotos prepared by Fraser Engineering from aerial photographs dated September-October 1988. The blueline orthophotos were produced from a set of mylars owned by the City of Carlsbad. 3.3 METHODS A preliminary vegetation map was generated based on photo interpretation by circumscribing vegetation communities (polygons) on the 400-scale blueline orthophotos using existing vegetation 32 maps from biological resources reports and observed distributions of vegetation types on the orthophotos. Figure 3 illustrates the total area from which field-generated vegetation maps were available. During this task, soils maps (Bowman 1973) and the 500-scale color aerial photograph were consulted to help define vegetation boundaries. Reconnaissance level field surveys were conducted by John Brown, Ph.D. (Dudek & Associates) and Sarah Rick (Michael Brandman Associates) in areas within the City where vegetation maps were incomplete, incompatible, or lacking. During the field surveys, any sensitive plant or animal species encountered were noted and incorporated into the data base. Terminology for vegetation communities employed are standardized community types as adopted by SANDAG for their GIS efforts. These communities types follow Holland (1986) for the most part, and are listed in Table 2. The 23 completed 400-scale vegetation maps were photo-reduced and combined to produce a 1,000- scale (1"=1,000') mylar of the preliminary vegetation map. The map was made available to private and public agencies and landowners/developers. Several planners, property owners, and developers (e.g., Hoffman Planning Associates, Fieldstone Company, etc.) submitted more detailed or more recent versions of the portion of the map that included their ownerships or planning areas. Each of these submissions were subject to field review before incorporation into the final vegetation map. During this review period, several other recent environmental documents became available (e.g., Lake Calavera EIR, Rancho Santa Fe Road EIR, Carrillo Ranch EIR, and the Aviara EIR), thus allowing further fine-tuning of the preliminary vegetation and sensitive species maps. A final set of 400-scale blueline maps of the vegetation communities was produced incorporating all of the data received. Clear mylars of the vegetation polygons were made by tracing vegetation lines from the 400-scale bluelines calibrated with the originals of the City of Carlsbad orthotopo mylars. Each polygon was labelled by a number code representing a specific community type (see Table 2). The clear mylars with vegetation boundaries and reference points were submitted to SANDAG for digitization. The vegetation plots produced by the SANDAG GIS system were submitted to team biologists to check the accuracy of presentation and adherence to the original orthophoto mapping. Locations of sensitive plant and wildlife species were transcribed onto the 400-scale bluelines orthophotos from existing biological documents. Sensitive species observed during field checking of the vegetation maps also were recorded on the maps. Also, all publicly available information regarding the distribution of the California gnatcatcher, as made available by Sweetwater Environmental biologists, were incorporated into the map. Locations of sensitive species were transferred onto the clear mylars of the vegetation communities and digitized by SANDAG subsequent to digitization of the vegetation communities. Locations of most sensitive species were identified by a point. However, large stands of specific sensitive plant species (e.g., California adolphia and Del Mar manzanita) were identified by small polygons. 3.4 RESULTS 3.4.1 VEGETATION MAP It is important to understand that the vegetation map was generated through photo interpretation of blueline orthophotos and existing vegetation maps from EIRs and other available technical documents. A limited amount of field work was conducted to field-check the accuracy of the maps. There are areas of the City that have not been surveyed beyond the photo interpretation provided here. This methodology is adequate to develop a general vegetation map, but is not intended to provide precise, site-specific vegetation information. Also, this methodology does not allow for vegetation descriptions more precise than the plant community level. To satisfy the requirements of the California Environmental Quality Act (CEOA), specific project areas will require focused field 33 surveys to fine-tune the information provided here, characterize the general biological resources of the site, and provide site-specific analyses of sensitive resources. Table 3 presents acreage by aggregated vegetation type for the City. More than 10,000 acres (40.9 percent) of the City of Carlsbad were mapped as developed. Approximately 10,200 acres (41 percent) of the City still support natural habitat. Of the natural habitat, approximately 7,150 acres (70 percent) are comprised of native habitats. Although there is natural habitat distributed throughout the City, the largest areas of contiguous habitat generally are located in the eastern portion of the City. With the exception of the lagoons, the western portion of the City is mostly developed or supports disturbed habitat. TABLE 3 ACREAGES BY AGGREGATED VEGETATION TYPES WITHIN THE CARLSBAD HABITAT MANAGEMENT PLAN STUDY AREA Vegetation/Land Cover Coastal Sage Scrub Disturbed Coastal Sage Scrub Chaparral Non-Native Grassland & Disturbed Grassland Native Grassland Salt/Freshwater Marsh Oak Woodland & Sycamore Alluvial Woodland Eucalyptus Woodland Open Water Disturbed Wetland Disturbed Habitat, Active Agriculture, Golf Course Developed Study Area 3,018 638 2,409 2,619 23 372 709 305 1,172 190 4,986 11,987 Percent of Total 10.6 2.3 8.5 9.2 0.1 1.3 2.5 1.1 4.1 0.7 17.3 42.3 City 2,503 633 1,727 2,449 22 358 618 302 1,102 190 4,545 10,191 Percent of Total 10.0 2.5 8.1 9.8 0.1 1.4 2.5 1.2 4.4 0.8 18.2 40.9 TOTAL 28,337 100 24,940 100 Sensitive habitats present within the City include 3,149 acres (12.6 percent of the City) coastal sage scrub (including maritime succulent scrub and disturbed coastal sage scrub), 22 acres of native grassland, 358 acres of salt- and freshwater marsh, and 618 acres of oak and sycamore alluvial woodlands. Chaparral, including southern mixed chaparral, chamise chaparral, southern maritime chaparral, and coastal sage scrub/chaparral, occupies about 1,727 acres (8.1 percent of the City). Among the subtypes of chaparral, southern maritime chaparral is considered sensitive by local and regional resource agencies. 34 3.4.2 SENSITIVE SPECIES MAP As with the vegetation map, it is important to note that the existing sensitive species information for the City is limited. The information provided here comes from published information, existing EIRs and other technical reports, and from communications with local biologists. While the data base is reasonably good for plants and birds, information on sensitive reptiles and amphibians, for example, is relatively poor — even for previously surveyed areas ~ because these species are often difficult to detect. Other areas have not been surveyed for sensitive species at all. Therefore, the sensitive species map can only be interpreted as evidence of positive findings. The absence of sensitive species may indicate areas inadequately surveyed or not surveyed at all. The results of the sensitive species mapping are presented in Figure 4. The most widespread sensitive plant species within the City include California adolphia and ashy spike-moss, primarily in coastal sage scrub; and wart-stemmed ceanothus, summer-holly, and Del Mar manzanita, primarily in southern maritime chaparral. In drainages and riparian areas spiny rush is fairly common. Other sensitive plants encountered less frequently include San Diego golden-star, western dichondra, Engelmann oak, San Diego sagewort, San Diego marsh-elder, San Diego thorn-mint, and thread-leaved brodiaea. The most widespread sensitive wildlife species present in the City is the federally-proposed endangered California gnatcatcher. This species is resident nearly everywhere that coastal sage scrub occurs. Figure 4 illustrates 113 gnatcatcher records, which includes both singletons and pairs. While recording absolute numbers is useful for quantifying the presence and distribution of the species in the City, it is important to note that numbers fluctuate from season to season and year to year, and that not all areas of the City have been thoroughly surveyed. Dr. Pat Mock of Ogden Environmental and Energy Services suggests that, based on a density estimate of one pair per 15 acres (which is an average home range in the San Diego area) and approximately 2,500 acres of coastal sage scrub in the City, Carlsbad could support as many as 166 pairs (P. Mock, pers. comm.). Thus, the number of gnatcatchers in the City is at minimum 113, with perhaps as many as 166. Other sensitive wildlife species encountered infrequently within the City include San Diego horned lizard and orange-throated whiptail in coastal sage scrub; California least tern, Belding's Savannah sparrow, and light-footed clapper rail in estuaries and salt marsh areas; and least Bell's vireo in willow riparian habitat. Although not represented in the sensitive species map, the California brown pelican and California least tern are common along the coast and in the lagoons in Carlsbad. 35 SECT ON 4 Biological Preserve Planning Area and Design Approach BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 4 BIOLOGICAL PRESERVE PLANNING AREA AND DESIGN APPROACH 4.1 INTRODUCTION A critical component of the HMP for the City of Carlsbad is the identification of areas within the City limits that are suitable for a system of biological preserves, conservation, or management areas. This section provides a discussion of the features used to identify biologically valuable areas. These factors then are incorporated in a quantitative methodology used to rank areas of the City in regard to their biological value, rarity, and uniqueness. The results obtained from the ranking method will form the basis for future decisions concerning habitat evaluation, acquisition, and implementation and management of an HMP that are consistent with the City's General Plan, as well as state and federal conservation planning efforts (e.g., NCCP and Habitat Conservation Plans [HCP]). It is important to consider the conservation effort of the City in the context of other planning efforts in San Diego County and the Southern California region (e.g., the MSCP, the North County MHCP, and the NCCP for coastal sage scrub). Carlsbad, by itself, likely does not have enough remaining natural habitat to conserve any of the sensitive habitats or species of concern occurring in the City in perpetuity (100- or 200-year survival with a 95 percent probability are common definitions of perpetuity used by conservation biologists). However, by developing an HMP that is consistent with other conservation planning efforts, and through mutual cooperation with other jurisdictions in the region, Carlsbad can make a significant contribution to the conservation of native habitats and species in Southern California. Within this context, therefore, the HMP does not purport to provide a comprehensive, stand alone preserve system for sensitive habitats and species. Rather, the purpose of the HMP is to provide a program that contributes to overall conservation efforts and maintenance of functional ecosystems in Southern California. 4.2 PRESERVE DESIGN LITERATURE REVIEW 4.2.1 SIZE Much of the literature on the design of nature preserves has focused on the physical characteristics of the preserves, including their shape, size, and degree of isolation from other areas of natural habitat. When the primary goal of a preserve system is to minimize the probability of extinction of its component species and maintain a functional ecosystem, larger preserves are more effective than smaller ones. In isolated patches of habitat, it has been shown empirically and theoretically that the rate of species extinction is inversely related to patch size (Diamond 1975; Wright and Hubbell 1983; Usher 1987; Soule 1991). The preserve size required to maintain various kinds of ecosystems is poorly understood and requires much more scientific study. In general, the smaller the preserve, the greater the level of protection and hands-on management it will require to remain viable (Noss 1983). There are several reasons why large preserves may be superior to small ones. Smaller preserves necessarily support smaller populations of organisms. These small populations are more prone than larger ones to chance fluctuations in birth and death rates which, when extreme, can lead to local extinction (Wilson and Willis 1975; Shaffer 1981; Jensen 1987). Small populations also will lose genetic variation as a consequence of genetic drift more rapidly than large populations (Franklin 1980; Lacy 1987). Loss of genetic variation can negatively affect a population of organisms because it results in higher levels of homozygosity, a condition in which a pair of genes at a particular location on a chromosome are alike. Homozygosity can be associated with poor growth, higher frequencies 36 of disease, and decreased survival during periods of stress (Soule and Simberloff 1986). Over the longer term (from decades to thousands of years), depletion of genetic variation in small populations can lead to an inability to adapt to changing environmental conditions, and ultimately to population extinction (Lacy 1987; Lande and Barrowclough 1987). 4.2.2 SHAPE The shape of a preserve also can influence its ability to effectively conserve native species. At their borders, nature preserves often will be subject to negative influences or "edge effects" from the outside, including increased levels of predation and nest parasitism (e.g., cowbirds laying eggs in vireo nests), microclimatic changes (e.g., increased sunlight and temperature), and direct destruction of native vegetation and wildlife by human uses (Schonewald-Cox and Bayless 1986; Yahner 1988). Edge effects are strongest on habitat fragments that are small and irregularly shaped (Forman and Godron 1981; Laurence and Yensen 1991). Several studies have considered the effect of increasing perimeter relative to preserve size using a variety of quantitative measures (Faeth and Kane 1978; Game 1980; Blouin and Conner 1985). Although the relationship between preserve shape and immigration and emigration rates requires further investigation, it is generally true that preserves that are circular in shape will have the least amount of edge for their size and thus will be least vulnerable to edge effects. The extent and severity of edge effects ultimately will depend on the nature of the habitat surrounding a preserve. In urban areas where immediate threats from "human-commensal" species (e.g., pets and some pest species) exist at the edges of preserve boundaries (Murphy 1988; Soule et al. 1988), the ratio of edge to interior probably should be minimized whenever possible. 4.2.3 ISOLATION/WILDLIFE CORRIDORS The degree of isolation of individual preserves also is an important design consideration, and in some cases, may be at least as significant for the maintenance of regional biodiversity as overall preserve size (Noss 1983). Both demographic (considering factors such as population size, reproduction, mortality, emigration, and immigration) (Fahrig and Merriam 1985; Burkey 1989) and genetic (Boeklen 1986; Boeklen and Bell 1987; Lacy 1987) models predict that higher levels of migration between preserves will lead to lower probabilities of extinction. Only modest levels of migration (one or two migrants per subpopulation per generation) may be required to mitigate the negative genetic effects of population fragmentation (Lande and Barrowclough 1987). These models lead to the design recommendation that isolated preserves be located as close together as possible in order to facilitate exchange of individuals between subpopulations (Diamond 1975; Wilson and Willis 1975). For species reluctant or unable to move through non-natural habitats (e.g., golf courses or agricultural fields), the incorporation of habitat linkages (e.g., a wildlife corridor) into the design of a preserve system is critical. Although empirical research on the optimal design for linkages is lacking, computer simulations have been useful in identifying some of the basic factors that may influence habitat linkage utility. Effective linkages must be wide enough to resist edge effects, contain the appropriate habitat(s) of the key species expected to travel through them or use them for dispersal, possess adequate cover to prevent excessive predation on migrants or dispersers, and contain as few turns or other barriers to movement or dispersal as is feasible (Soule and Gilpin 1991). In addition, networks of several habitat linkages probably provide a better system for migration and dispersal than single connections because alternative routes are available (Forman and Godron 1981; Noss 1987). 4.2.4 BUFFERS AND DISTANCE SETBACKS In order to maintain the integrity of biological resources adjacent to development or other land uses generally considered incompatible with biological resource areas (e.g., active recreation areas that receive heavy human use), the interface between natural open space and development (sometimes 37 called the natural/urban interface) must include an appropriate buffer area. Strictly defined, the "buffer" includes the area between the open space boundary and the boundary of a specific development or land use. It is assumed that habitat within the buffer area will be degraded by human-caused disturbance and, thus, the area should not be considered part of the "preserve". Various approaches have been taken to quantify disturbance from development and specify appropriate buffers for biological resources in Southern California (Scott 1992; Sauvajot 1992; Kelly and Rotenberry 1992). It is clear that no single approach or specific buffer distance will satisfy the buffer needs for different resources under different levels of pressure from development. In San Diego, for example, a table of distance setbacks between land-use types and biological resources was developed by Pacific Southwest Biological Services (PSBS). A comparable set of guidelines has been developed for the San Diego County Resource Protection Ordinance (RPO). However, the recommended buffer distances deviate greatly between the two lists. Dudek & Associates has developed a set of buffer values that represents a compromise between the PSBS and RPO recommendations. The ranges of buffers are meant to provide a general guideline and are not intended to act as rigid standards. Also, these guidelines derive from qualitative input from experienced field biologists and do not come from scientific field studies. Unfortunately, thoroughly tested and validated field data do not exist at this time, although ongoing studies should provide some data on the question of buffers in the next two to four years (Scott 1992; Sauvajot 1992). Each specific natural/urban interface should be evaluated independently considering the guidelines and the biological sensitivity of the habitat and wildlife species adjacent to development. Flexibility in setback distance is necessary to reasonably and logically accommodate the varying quality or sensitivity of resources within natural open space adjacent to proposed land uses. For example, buffer width should be greater between high quality coastal sage scrub and residences, because high quality coastal sage scrub is likely to support more sensitive species. Narrow riparian corridors may require wider buffers than broad riparian corridors in order to allow comparable unobstructed open space to facilitate wildlife use and movement. Topographic barriers, such as canyons, rock outcrops, steep slopes, and elevational differences, may render prescribed buffer distances inappropriate. Finally, simple linear calculations or formulas for buffers may be inappropriate when development patterns create variations in the contour of the natural urban interface. For example, a development with an undulating boundary or corners at acute angles (i.e., less than 90 degrees) will result in open space peninsulas which share more border with the development than a development with square angles. In this situation, the buffer would have to be greater to compensate for the greater interface area. Ideally, no recreational activities or active land uses would be permitted within buffer areas. In some buffer areas, however, passive recreation may be an acceptable use. Whether recreational activities are acceptable in certain buffers will depend on the characteristics of the buffer, the sensitivity of the natural area, and the planned recreational use. Hiking and equestrian trails, for example, would be appropriate in many buffer areas while off-road vehicles would not. While natural habitat not designated as open space is the preferred buffer, cut slopes, fills, brush management zones, and fuel breaks may be acceptable depending on the type of habitat. Some general suggestions for specific habitat types, based on the RPO standards and PSBS recommendations, are provided below. It is important to keep in mind that these guidelines only provide minimum buffer sizes, that each case must be evaluated independently, and that there is little scientific data or even agreement among biologists regarding the appropriate buffer distances in any given setting. 38 Coastal Sage Scrub and Chaparral In general, scrub communities such as coastal sage scrub and chaparral should be provided with at least a 100-foot buffer where interfacing with residences and a 50 to 75-foot buffer where interfacing with commercial and industrial development, active park uses, and schools. For coastal sage scrub and chaparral communities occupied by sensitive plants, the buffers are the same as cited above, because plants are unlikely to be affected by noise and light impacts associated with these types of developments. The greatest risk to sensitive plants is from trampling by human foot traffic, mountain bikes, and motorized off-road vehicles. For coastal sage scrub occupied by California gnatcatchers and other sage scrub avian species, a buffer of at least 200 feet is recommended at interfaces between residential and commercial development and the occupied habitat. Occupied habitat can be defined as the native vegetational community that is within the territory of a single pair of birds. Grasslands For annual (non-native) and perennial (native) grasslands, buffers of at least 20 to 50 feet are recommended between the habitat and proposed residential and commercial development. Again, the precise buffer distance should be determined by the quality and quantity of the specific grassland habitat. For some annual grasslands, a buffer may be inappropriate or unnecessary under certain conditions; for instance, where the grassland does not represent sensitive plant or wildlife habitat or does not serve a corridor function. Mulefat Scrub As a component of the riparian system, mulefat scrub should be provided with a buffer that is 50 to 100 feet wide, depending on the quality of the habitat and its function within the matrix of the surrounding vegetation (e.g., corridor, foraging habitat). The County RPO specifies that 25 feet is the minimum buffer for riparian habitat; PSBS suggests 100 feet for most interfaces between mulefat scrub and development. Southern Willow Scrub/Riparian Habitat Throughout Southern California, southern willow scrub/riparian woodlands are recognized as highly productive habitats. The structural diversity of the woodlands and the availability of water and food resources combine to support a rich diversity and abundance of wildlife species. According to the County RPO, the "appropriate width of a buffer adjacent to an area of riparian habitat varies depending upon specific site conditions." The RPO recommends a minimum buffer of 25 feet, but indicates that buffers up to 200 feet may be required in some instances to maintain the biological viability of the habitat. To avoid disturbance to resident wildlife, it is recommended that buffers between riparian woodlands and commercial and residential development be at least 100 feet wide. Where riparian woodlands are occupied by least Bell's vireo, buffers should be based, to a large extent, on the width of the riparian corridor. The USFWS, for example, has indicated that the average width of vireo-occupied habitat on the San Luis Rey River is approximately 800 feet. Assuming that the 800-foot corridor is appropriate for vireo habitat, buffers should be large enough to accommodate this width. Hence, if the riparian corridor is 200 feet in width, buffers of at least 300 feet on each side are appropriate (i.e., 300 feet -I- 200 feet + 300 feet = 800 feet). The RPO suggests 200 feet and PSBS suggests 500 feet as buffers to vireo-inhabited riparian areas. Oak Woodland Oak woodlands support considerably more wildlife species than the scrub and grassland communities discussed above. More than 300 vertebrate species are known to utilize oak-dominated woodlands 39 in California for reproduction, overwintering, and during migration (Block et al. 1990). Human disturbances to oak woodlands are particularly acute because these woodlands generally are easily accessed by the public and thus are adversely affected by legitimate recreation activities (i.e., hiking, mountain bikes, picnicking, etc.) as well as by illegitimate uses (trash dumping, vandalism, itinerant worker camps, shooting, etc.). Preliminary scientific information concerning urban effects on oak woodlands adjacent to residential housing indicates a decline in bird species diversity resulting from the influx of people and human-commensal species such starlings and house sparrows (Scott 1992). The County RPO sets minimum buffer for oak woodlands at 25 feet from the dripline of an individual tree or from the edge of an oak woodland. However, to reduce disturbance to wildlife, it is recommended that buffers between oak woodlands and development be at least 50 to 100 feet wide. Furthermore, oak woodlands designated as part of a biological preserve either should be off- limits to the public or receive controlled numbers of visitors engaging in passive recreation activities (e.g., nature hikes or bird watching restricted to established trails). 4.2.5 OTHER CONSIDERATIONS In addition to the physical aspects of preserve design, several authors have discussed biological design criteria, including where preserves ideally should be located, what types of communities and species they should contain, and how they ultimately should be managed. Biological criteria employed in past designs for preserves include the diversity, rarity, uniqueness, representativeness of the species, habitats, and natural communities contained in potential preserve areas (Tubbs and Blackwood 1971; Goldsmith 1975). Other studies have emphasized that the threat of human interference, availability of land containing undisturbed natural habitat, and ease of management, also should be considered in the location of preserves (Tans 1974; Gelbach 1975; Wright 1977). Margules and Usher (1981) stressed the benefits of using a quantitative scheme to assess the relative suitability of sites for inclusion in preserve systems. Some of the most successful methodologies have been those that incorporate information both on the biological value and manageability of natural areas, and outline procedures for differentially weighting chosen criteria (Duever and Noss 1990). Fundamental differences between ecosystems necessitate that the physical and biological aspects of preserve design must be addressed independently for each preserve system. However, results of past studies provide useful general guidelines, especially with regard to which physical variables are important for long-term viability of preserves and how biological resources contained in different potential preserve sites might be compared objectively. 4.3 PRESERVE DESIGN RATIONALE AND APPROACH A "landscape" approach is used to identify critical biological resource areas in Carlsbad. This approach, which considers the existing biological diversity within the City, is based upon the following goals: • The primary goal is to conserve large landscape-sized features in an interconnected system of self-sustaining (i.e., independent) ecological units. Although management will be an important component of the HMP, preserved areas should remain viable without extreme intervention measures, including extensive vegetative restoration or translocation of species. • A secondary goal is to conserve areas known to support viable populations of state and federally listed endangered and threatened species and their habitats, those species and habitats likely to become threatened, endangered, or rare in the future, and other species or habitats of concern on the state, regional, or local level. 40 The methodology used for the biological resource analysis was as follows: • An attempt was made to broadly categorize areas as to their overall biological value and sensitivity rather than to plan for a particular subset of species. Because limited time and money precluded focused, detailed biological surveys throughout the City, general habitat and vegetation information, specific information from previous biological surveys (e.g., from EIRs), consultation of resource data bases (e.g., CNDDB and CNPS), and interviews with local biological experts served as the information base for identifying the critical resource areas. • Preserve design criteria and evaluation follow from general conservation principles and biogeography theory, as discussed above. 4.4 PRESERVE DESIGN METHODOLOGY The methodology for identifying potential preserve areas and developing a ranking system for components of the preserve system is described in this section. This approach serves as a guideline for identifying potential preserve units. The approach was not meant to assign absolute biological values to each of the units or areas considered for preservation, but to provide relative values for comparisons among areas. For this reason, while there is a solid scientific foundation for the preserve design features chosen, the point values assigned in the ranking system were somewhat arbitrary. The main goal was to develop a ranking system that could be applied objectively and fairly to each of the areas considered for preservation. This approach represents an amalgamation of approaches used in other settings (e.g., Duever and Noss 1990; ERCE 1991), but tailored to the needs of the City of Carlsbad as allowed by the available funds and time to develop the information. 4.4.1 FOCUSED PLANNING AREAS As an initial step, undeveloped areas within the City of Carlsbad were divided into seven or eight focused planning areas (FPAs). For purposes of our analyses, "undeveloped areas" were defined in two alternative ways: (1) all areas that presently are mostly vacant (i.e., without permanent physical structures) and do not have an approved tentative map (Figure 5); and (2) all areas that presently are vacant, including those with an approved tentative map (Figure 6). The reason for two different sets of FPAs is that areas with approved tentative maps may yet be constrained from development if the California gnatcatcher is federally listed as endangered. Under Section 9 of the federal ESA, any lands with gnatcatchers would be protected until issuance of a Section 10(a) incidental take permit or a permit issued pursuant to Section 7 (in the case of a federal action linked to the project). Lands with gnatcatchers thus would be potential preserve areas even if they had an approved tentative map. The first alternative (i.e., the pre-gnatcatcher listing scenario) resulted in eight distinct FPAs. The second alternative (i.e., the post-gnatcatcher listing scenario) resulted in seven distinct FPAs. The FPAs were delineated by circumscribing large, continuous areas of the relatively undeveloped land. Major existing roadways (e.g., El Camino Real and Palomar Airport Road) and existing or proposed development (under alternative 1) provided relatively natural and intuitive boundaries for the FPAs. Using GIS, the entire City of Carlsbad and some adjacent areas in San Marcos and Encinitas were overlain with a grid comprised of cells 1,000 feet on each side. Each cell contains 22.9 acres. The grid approach was used because it provides a neutral, objective method for dividing up the focused planning areas into analyzable units. Public and private property boundaries, proposed land uses, and circulation elements, which likely will affect the configuration of the preserves, were explicitly 41 NOTE:Focused Planning Areas include those areas without an approved tentative tract map and which are mostly vacant. SOURCE: SANDAG, April 1992 1" = 6000' Carlsbad Habitat Management Plan Pre-Gnatcatcher Listing Focused Planning Areas NOTE:Focused Planning Areas include those areas that are presently vacant and with or without an approved tentative tract map. SOURCE: SANDAG, April 1992 1" = 6000' Carlsbad Habitat Management Plan Post-Gnatcatcher Listing Focused Planning Areas excluded from this analysis in order to focus only on biological factors. Also, a grid system is much more amenable to computer analysis using the GIS data base. The GIS output from SANDAG was used to generate an overall rating of two features, habitat value (HV) and habitat sensitivity (HS), utilizing separate layers with vegetation community distributions and sensitive species. (Vegetation communities and habitat are treated as synonymous here because each native or introduced community, including introduced eucalyptus, provides habitat for a variety of species). After each of the cells was rated on HV and HS, they were ranked for their importance for inclusion in a preserve system. It was assumed that sets of adjacent cells with high rankings would become the building blocks for the preserve system. Evaluation of HV was based on: (1) the amount of natural habitat in the cell, including coastal sage scrub, chaparral, native and non-native grassland, riparian scrub, oak woodland, eucalyptus woodland, freshwater marsh, salt marsh, disturbed wetland, and open water; (2) the number of different habitats represented; (3) the connectivity of natural habitats in the cell with habitats of the same type in cells sharing a side with the focal cell (i.e., excluding cells that connect on the corners); and (4) vulnerability and manageability, based on land use in the adjacent cells. Each cell was rated for each feature and given a total HV rating, with a maximum of 100 points. Evaluation of HS of each cell was based on: (1) the presence and amount of sensitive habitat; (2) the diversity of sensitive habitats; (3) the presence and abundance of the California gnatcatcher and coastal sage scrub; (4) numbers of sensitive plant species; and (5) numbers of sensitive wildlife species. Each cell was rated for each feature and given an HS rating, with a maximum of 100 points. A separate category for presence of the California gnatcatcher was added because the species is likely to be federally listed as endangered, and thus will be a key environmental issue for the preserve system. 4.4.2 PRESERVE FEATURE DEFINITIONS AND RATINGS - HABITAT VALUE Habitat value refers to the general biological value of each of the cells based upon the presence of natural vegetation. The presence of sensitive habitats, endangered or threatened species, or other sensitive biological resources were not considered or given extra weight for the HV rating. The goal of rating cells for HV simply was to identify those areas that have the best remaining natural vegetation and habitat in Carlsbad, and those areas that will provide the foundation for a diverse biological preserve system. Amount of Natural Vegetation/Habitat Areas This feature addresses the amount of natural communities or habitat within a cell. The amount of natural habitat is an important factor for the contribution of a cell to the overall biological viability of the preserve system. The goal is to assemble several contiguous cells, each with substantial natural habitat, into a cohesive, self-sustaining ecological preserve area. Also, cells with large amounts of natural habitat are likely to presently contain more species diversity than cells with less habitat, and sustain biological diversity (community and species diversity) over long periods of time (Alberts et al. 1992). "Natural communities" encompass coastal sage scrub (all subassociations), chaparral, native grassland, riparian scrub, disturbed wetland, oak woodland, freshwater marsh, salt marsh, open water, and non-native associations including eucalyptus woodland and non-native grassland. 42 Criteria and points for amount of habitat were as follows: Criteria Points > 22 acres 25 17 to 22 acres 20 11 to 16 acres 15 4 to 10 acres 10 < 4 acres 0 Community/Habitat Diversity This feature addresses the number of different natural vegetation communities or habitat types within a cell. The assumption was that cells with several different communities will have relatively more biological value than cells with little diversity. This assumption, however, is not always correct or useful. In the case of coastal sage scrub or freshwater marsh, for example, a cell with a single sensitive community may have extremely high biological value. Such cells were considered on the HS rating to ensure that they were not undervalued in the final ranking of the cells. For the purpose of assessing community diversity, the vegetation and habitat types listed above were used. Community types that have subassociations (e.g., coastal sage scrub and chaparral) were considered as a single community type. Unfortunately species diversity within a community could not be considered for the analysis because there are too little current field data. Detailed field investigations would be required to address species diversity. Criteria and points for natural community/habitat diversity were as follows: Criteria Points > 5 communities 25 4 or 5 communities 20 2 or 3 communities 15 1 community 10 0 natural communities 0 Connectivity of Cell This feature addresses whether or not a cell has meaningful biological connectivity to adjacent cells. An adjacent cell was defined as a cell that shares a side with the focal cell. Cells that connect at the corners of the focal cell were not included in this analysis because the connection is at only a single point. Thus, each focal cell is adjacent to four other cells. Meaningful biological connectivity was defined as adjacent cells containing the same community type. For example, if coastal sage scrub occurs in adjacent cells, those cells are considered to have meaningful biological connectivity because the species within those cells would comprise a single population, even though the habitat may not be strictly continuous. Furthermore, the "continuous" habitat could serve as a habitat linkage to 43 other, disjunct cells. The connectivity feature is important for assembling several biologically valuable units into a cohesive preserve area. The degree or value of connectivity was determined by how many sides of the focal cell connect with adjacent cells having the same habitat. A cell that connects to three or four other cells clearly is more valuable as a preserve unit than a cell with only one connection; i.e., an edge unit (although the edge unit may serve as an effective buffer). A difficulty that arises with this feature, as defined, is that focal cells bordered by cells with very small patches of habitat would be given high scores even though the biological "connection" value of the habitats would be relatively low, particularly with habitats such as coastal sage scrub, chaparral, and non-native grassland. These habitats must be at least a few acres in size to have much long-term biological value. Other habitats such as riparian woodland, scrub, marsh habitats, and open water may have relatively high value even if they comprise only a few acres. To offset the problem of inflated connectivity scores, adjacent cells had to contain at least one acre of coastal sage scrub, chaparral, or non-native grassland to be scored as an adjacent cell with the same habitat. The criteria and points for connectivity were as follows: Criteria Points 4 sides connecting to same habitat 25 3 sides connecting to same habitat 20 2 sides connecting to same habitat 15 1 side connecting to same habitat 10 0 sides connecting to same habitat 0 Land Uses Adjacent to Cell This feature addresses whether land uses in adjacent cells are compatible with the biological viability and integrity of the focal cell. The assumption was that residential, commercial, and industrial development are existing land uses relatively incompatible with the biological viability of a focal cell because of the potential for human disturbance, including active recreation (e.g., off-road vehicles or mountain bikes), predation by pets, trash dumping, and chemical spills. Ultimately edges of the preserve areas will border adjacent land uses that likely will pose some threat to the preserves. However, the overall management plan should include measures to minimize adverse impacts on the preserves by adjacent land uses (e.g., the development of buffers, anti-pet fencing, and deed restrictions). For the purpose of rating each cell, cells surrounded by natural habitats of any type received the highest rating, and those surrounded by development or disturbed habitat received the lowest rating. By definition, an adjacent cell with at least 20 acres of natural habitat was considered undisturbed. 44 The criteria and points for adjacent land uses were as follows: Criteria Points At least 20 acres natural 25 habitat on 4 sides At least 20 acres natural 20 habitat on 3 sides At least 20 acres natural 15 habitat on 2 sides At least 20 acres natural 10 habitat on 1 side Less than 20 acres natural 0 habitat on any side 4.43 PRESERVE FEATURE DEFINITIONS AND RATINGS -- HABITAT SENSITIVITY The habitat sensitivity rating considers the presence of sensitive vegetation communities or habitat, such as coastal sage scrub or wetlands, and the presence, or potential presence based on habitat, of sensitive wildlife or plants species. Because the proposed endangered California gnatcatcher and coastal sage scrub is a key issue for development of the HMP, and several other federal candidate species occupy coastal sage scrub, gnatcatchers and coastal sage scrub were given a separate category. Amount of Sensitive Habitat This feature addresses the question of how much, if any, sensitive habitat a cell contains. Sensitive habitat includes coastal sage scrub (including all subassociations), southern maritime chaparral, oak woodland, riparian scrub, freshwater marsh, salt marsh, open water, and native grassland. The criteria and points for amount of sensitive habitat were as follows: Criteria Points > 22 acres 20 15 to 22 acres 15 9 to 14 acres 10 2 to 8 acres 5 < 2 acres 0 Five points were added if the cell supports any sensitive habitat other than coastal sage scrub. (This accounts for the problem that some sensitive habitats often cover small areas, such as wetlands, riparian woodland, or native grassland.) 45 Diversity of Sensitive Habitats This feature addresses the diversity of sensitive habitats within a cell. The assumption was that the greater the diversity of sensitive habitats within a cell, the greater its biological value and the more valuable it would be for acquisition. The criteria and points for the diversity of sensitive habitats were as follows: Criteria Points 4 or more sensitive habitats 20 3 sensitive habitats 15 2 sensitive habitats 10 1 sensitive habitat 5 0 sensitive habitats 0 California Gnatcatcher This feature addresses the presence of the California gnatcatcher or its habitat within a cell. Because the gnatcatcher is likely to be federally listed as endangered, preservation of gnatcatcher habitat is a high priority for the HMP. The highest ratings were given to cells that are known to support gnatcatchers and have the highest quality gnatcatcher habitat. Areas with coastal sage scrub, but no documented gnatcatchers received a lower rating. The criteria and points for gnatcatcher habitat were as follows: Criteria Points 2 gnatcatcher pairs 20 1 gnatcatcher pair 15 At least 15 acres of coastal 5 sage scrub, but no documented gnatcatcher pairs Less than 15 acres of coastal 0 sage scrub or no potential habitat Sensitive Plants This feature addresses whether the cell supports plant species that are recognized as sensitive, rare, or unique by the USFWS, CDFG, CNPS, or other regional or local organizations. The criteria and points for sensitive plants were as follows: 46 Criteria Points Documented presence of state or 20 federal endangered or threatened plant species Presence of federal candidate 15 species Presence of two or more CNPS 10 or locally-recognized sensitive species Presence of one CNPS or locally- 5 recognized sensitive species No documented presence of 0 sensitive species Sensitive Wildlife This feature addresses the presence of sensitive wildlife, or habitat with potential for supporting sensitive wildlife, within a cell. Sensitive wildlife was defined as both vertebrates and invertebrates that have state or federal endangered or threatened status, federal candidate species, state Species of Special Concern, or species considered sensitive, rare, or unique by regional or local agencies or organizations. Thus, any sensitive mammals, reptiles, amphibians, birds, or insects were considered here. Sensitive habitats that provides breeding, foraging, or refuge opportunities for sensitive wildlife also were considered. Criteria and points for sensitive wildlife were as follows: Criteria Points Documented presence of federal 20 or state endangered or threatened species Presence of federal candidate 15 or state Species of Special Concern Presence of at least 15 acres of 5 sensitive habitat 4.5 RESULTS - HABITAT VALUE As described in detail above, the analysis of habitat value (HV) for each of the cells was based on the amount of natural vegetation within a cell, the diversity of vegetation communities, the connectivity of the cells, and the adjacent land use. For the purpose of analysis, the grid was laid over a study area consisting of the entire City of Carlsbad and some adjacent areas to the south and east that contain natural open space (i.e., Encinitas and San Marcos), yielding a total of 1,237 cells (a total of 28,327 acres). A total of 1,179 cells (26,999 acres) occur either in part or whole in the Carlsbad City limits. Because the grid was placed in an arbitrary position over the study area, the 47 perimeter cells usually fall partly inside and outside of the City limits. Of the 1,237 cells, 977 cells (79 percent) scored at least 10 points. This accounts for 22,373 acres of the 28,337 acres in the study area (see Table 3). Cells scoring no points are located in the most urbanized areas of Carlsbad. Table 4 shows the frequency distributions for each of the features comprising the HV score. Each of the features is discussed below. 4.5.1 AMOUNT OF NATURAL HABITAT The frequency distribution for the amount feature illustrated in Table 4 demonstrates that the values for the feature are well distributed. There were 336 cells (34 percent) receiving scores of 20 or better (i.e., cells with 17 acres or more). There were 480 cells (49 percent) receiving scores of 10 or less (i.e., 10 or fewer acres). 4.5.2 HABITAT DIVERSITY For the diversity of vegetation communities, the scores for cells also were well distributed. However, the scores tended to fall more in the middle values than with the amount feature. Only five cells received scores of 25 (> 5 different communities) while only 11 cells received scores of 0 (no natural communities). However, 134 cells received scores of 20 or better (4 or more different communities). TABLE 4 FREQUENCY DISTRIBUTION FOR HABITAT VALUE FEATURES Habitat Value Features Assigned Value 0 10 15 20 25 Amount 244* 236 162 180 156 Diversity 11 302 531 129 5 Connectivity 73 50 147 264 444 Adjacent Land Use 450 272 165 62 29 TOTAL 978 978 978 978 The number or frequency of cells assigned a particular value 48 4.5.3 HABITAT CONNECTIVITY Cells tended to fall at the high end of values for the connectivity feature; 444 cells (45 percent) received scores of 25. The reason for this result is because the threshold for inclusion as a connected adjacent cell was fairly liberal. If a cell had any habitat that was the same as the focal cell, except for coastal sage scrub, chaparral, or non-native grassland, it was scored as a connected adjacent cell. This liberal criterion was used because even very small patches of certain vegetation communities, such as riparian woodland, salt and freshwater marsh, or native grassland, have high biological value and are valuable if proximate to the same habitat in an adjacent cell. For coastal sage scrub, chaparral, and non-native grassland, the threshold for scoring as an adjacent cell was that it must contain at least one acre of the same vegetation community. The rationale for this contingency is that these communities require somewhat larger areas to provide viable habitat for wildlife and plant species. The one acre requirement thus eliminates slivers of extremely small patches of vegetation that carry relatively little biological value. 4.5.4 ADJACENT LAND USE Adjacent land use scores provided almost a mirror image of the distribution for connectivity; 722 cells (74 percent) scored 0 or 10 and only 256 cells (26 percent) scored 15 or more. In other words, relatively few cells have adjacent cells with 20 or more acres on at least two sides. 4.5.5 COMPOSITE HABITAT VALUE Table 5 shows the composite HV frequency distribution. This distribution reflects the total score of each of the cells achieved by adding the scores for each of the HV features discussed above. No cells had a perfect score of 100. The overall distribution approximates a normal (bell-shaped) distribution, with most of the scores falling in the middle of the distribution. There were, however, a disproportionate number of scores, assuming a normal distribution, with a score of only 10. These cells are located in the more urbanized areas of Carlsbad and tend not to occur in the FPAs. Overall, 228 cells (23 percent) scored 75 points or better, 382 cells (39 percent) scored 50 to 70 points, 269 cells (27 percent) scored 25 to 45 points, and 98 cells (10 percent) scored 20 points or fewer. The spatial distribution of HV scores is illustrated in Figure 7. The map illustrates that cells with the highest scores tend to cluster together. Clustering here is defined as a focal cell having a direct connection with another cell either by sharing a side or connecting on a corner. Only four of the 228 cells scoring 75 points or more were not in some way directly connected (including a connection on a corner) to an adjacent cell scoring at least 75 points. In part, this is because connectivity was a factor in the HV score, but it also reflects the fact that Carlsbad still has relatively large, contiguous areas with high habitat value. Approximately 5,100 acres of the best habitat in Carlsbad generally occurs together. These clusters range in size from about 850 acres in the southeast part of the City to about 68 acres in the northern part. Cells that received scores between 50 and 70 tend to surround the highest scoring clusters. Cells with lower scores tend to be around the perimeter of the higher scoring clusters and in the areas outside of the FPAs. Only five of 96 cells scoring 20 points or fewer are completely surrounded by cells scoring at least 25 points. Figure 7 shows that the FPAs do indeed capture most of the best remaining habitat in Carlsbad. 49 Points B75 + 50-74 4- Q25 - 49 DO - 24 SOURCE: SANDAG, August 1992 Approx. Scale: 1" = 5900' Carlsbad Habitat Management Plan Habitat Value Map TABLE 5 COMPOSITE HABITAT VALUE Value Frequency Value Frequency 10 15 20 25 30 35 40 45 50 57 7 34 44 59 40 67 59 77 55 60 65 70 75 80 85 90 95 84 77 70 74 80 63 53 28 4 TOTAL 977 4.6 DISCUSSION -- HABITAT VALUE Decisions concerning habitat acquisition and implementation of the preserve and corridor system will in large part rest on the habitat value of the parcels considered for acquisition, as well as upon acquirability, economic, and land use factors. Any strategy, however, will allow for acquisition of only a portion of the remaining natural habitat within the City. The optimum strategy is to acquire and conserve the best remaining core areas and link them by multiple habitat corridors. The results of the HV analysis indicate that Carlsbad should have reasonably good flexibility in establishing an interconnected preserve system, because there are six or seven core areas with generally high habitat value. Some subset of three or four of these areas, with corridor linkages connecting all or part of the system, would be desirable. Most important, it appears that Carlsbad at least has the raw biological material from which to assemble a functional preserve system. While an analysis of general HV is an important aspect of delineating potential preserve areas, information about general species richness and the presence of sensitive habitat and species also is important. The HV analysis provides a starting point from which to consider the other factors important for designing feasible and functional preserves. The next section considers the presence and distribution of sensitive habitat and species. 4.7 RESULTS -- HABITAT SENSITIVITY The analysis of habitat sensitivity (HS) for each cell was based on the amount of sensitive habitat(s) within the cell, the presence of, or habitat for, the California gnatcatcher, the presence of sensitive plants, and the presence of sensitive wildlife species. Sensitive habitats included coastal sage scrub (including all subassociations), southern maritime chaparral, oak woodland, riparian scrub, freshwater marsh, salt marsh, open water, and native grassland. 50 4.7.1 AMOUNT OF SENSITIVE HABITAT The frequency distribution for the amount of sensitive habitat within a cell is well distributed (Table 6). Most cells scored relatively low, but 268 cells (27 percent) received 15 or 20 points. These 23- acre cells contain at least 15 acres of sensitive habitat. This kind of distribution was expected because sensitive habitats, by definition, are more rare and comprise fewer total acres than other habitats. This is especially true for riparian, marsh, and native grassland habitats. 4.7.2 SENSITIVE HABITAT DIVERSITY The frequency distribution for the diversity of sensitive habitats is similar to that for the amount of sensitive habitat. Most cells received a low score, but 129 cells (13 percent) received 15 or 20 points. That is, these cells contain three or more different sensitive habitats within the same cell. TABLE 6 FREQUENCY DISTRIBUTION FOR HABITAT SENSITIVITY FEATURES Habitat Sensitivity Features Assigned Value 0 5 10 15 20 Size 267 218 225 133 135 Diversity 164 457 228 % 33 Gnatcatcher Presence 833 65 NA 66 14 Sensitive Plants 820 105 34 9 10 Sensitive Wildlife 742 150 NA 5 81 TOTAL 978 978 978 978 978 4.7.3 CALIFORNIA GNATCATCHER Table 6 and Figure 4 show the most recent publicly available information concerning the distribution of California gnatcatchers in the City of Carlsbad. (It is important to note that all not all areas of the City have been surveyed for gnatcatchers nor were all data available for public review at the time of this writing.) Cells scoring 20 points had two gnatcatcher pairs, cells scoring 15 points had one pair, and cells scoring 5 points had no documented pairs, but contained at least 15 acres of coastal sage scrub, and thus have at least some potential to support gnatcatchers. Figure 4 illustrates that the gnatcatcher distribution tends to cluster similarly to cells scoring high in habitat value (see Figure 51 7), with the exception of 17 pairs in disjunct or isolated cells (i.e., cells having no direct connection with another cell either containing gnatcatchers or having at least 15 acres of coastal sage scrub). 4.7.4 SENSITIVE PLANTS Table 6 shows the distribution of cells containing plants with three levels of sensitivity: state or federally threatened or endangered, federal candidates, and CNPS or locally-recognized sensitive species. Only 10 cells contained plants with the most sensitive status and only nine cells contained federal candidate species. Plants with CNPS or local status were found in 139 cells. 4.7.5 SENSITIVE WILDLIFE The California gnatcatcher is a proposed endangered species. However, because it is likely to be listed as endangered by early 1993, it was treated in the analysis as federally endangered. The gnatcatcher was also included under sensitive wildlife, in addition to its own category, because of its high profile in the HMP process. In essence, it receives more than double weighting in this analysis because any cells containing a single gnatcatcher pair receives 20 points. Table 6 shows that 81 cells received 20 points; 80 of which contain gnatcatchers and one of which contains a least Bell's vireo. Only five cells contain federal candidate species, including the San Diego horned lizard and orange- throated whiptail (see Figure 4). Because the data base for sensitive wildlife is primarily comprised of biological surveys conducted for EIRs, there is a paucity of information on sensitive wildlife compared to the amount of information available on the presence of sensitive habitats and gnatcatchers. The absence of other sensitive species from cells may only reflect a lack of focused surveys for these species. Prior to acquisition of habitat for the preserves, additional focused surveys for sensitive wildlife will be necessary if this factor is to be an important acquisition criterion. 4.7.6 COMPOSITE HABITAT SENSITIVITY Table 7 shows the composite frequency distribution for HS resulting from adding the feature scores for each cell. The scores are well distributed, but skewed toward the lower scores. This was expected due to the rarity and uniqueness of the biological resources considered sensitive. Only eight cells (< 1 percent) scored 75 points or more, 74 cells (7 percent) scored 50 to 70 points, 284 cells (29 percent) scored 25 to 45 points, and 612 cells (62 percent) scored 20 points or fewer. Cells with higher HS scores tend to be clustered in the FPAs (Figure 8). Only 14 of 82 cells (17 percent) that scored more than 50 points are completely isolated from other cells scoring at least 50 points. Twelve cells scoring at least 50 points are connected only at the corner with another cell scoring at least 50 points. In other words, of the 82 cells scoring at least 50 points, 56 (68 percent) share at least a side with another cell scoring 50 or more points. As would be expected, the distribution of cells with high HS scores generally matches the distribution of cells with high HV scores. However, because the HS score represents more rare and unique biological resources, the absolute scores for HS are generally lower than HV scores on a cell by cell comparison. Only two cells that scored at least 75 on HS scored lower than 75 on HV. 52 Points 875 + 50-74 +- Q25 - 49 DO - 24 I SOURCE: SANDAG, August 1992 Approx. Scale: 1" = 5900' Carlsbad Habitat Management Plan Habitat Sensitivity Map Value TABLE 7 COMPOSITE HABITAT SENSITIVITY Frequency Value Frequency 0 5 10 15 20 25 30 35 40 143 108 164 95 102 68 76 70 44 45 50 55 60 65 70 75 75 80 85 26 19 19 17 9 10 3 3 3 2 TOTAL 978 4.8 HABITAT SENSITIVITY - DISCUSSION As with overall HV, the distribution of cells with high HS scores generally are concentrated in the FPAs. An acquisition strategy that focuses on cells with high HV usually will include the cells that have high HS scores. However, some relatively isolated cells receiving high HS scores may be worth acquiring, because they contain resources, such as a sensitive plant, that can be protected with only a small amount of habitat. Consequently, those cells with high HS scores should be evaluated individually to determine whether they should be acquired. 4.9 TOTAL HABITAT VALUE/SENSITIVITY -- RESULTS For each cell, the HV and HS scores were summed to yield a total HV/HS score (Table 8). Only 13 cells (1 percent) scored at least 150 points, 257 cells (26 percent) scored 100 to 145 points, 456 cells (47 percent) scored 50 to 95 points, and 252 cells (26 percent) scored less than 50 points. Cells that scored at least 100 points account for approximately 6,183 acres of the approximately 10,000 acres of natural habitat remaining in the City of Carlsbad. As with HV and HS considered separately, cells with high total HV/HS scores are clustered in the FPAs (Figure 9). Only six cells within the City boundaries scoring at least 100 points are completely isolated from other cells scoring at least 100 points. Only seven cells scoring at least 100 points are connected only at a diagonal to another cell scoring at least 100 points. All other cells scoring at least 100 points connect on at least one full side with another cell scoring at least as well. 53 Points 150 + 100 - 149 Q50 - 99 DO - 49 SOURCE: SANDAG, August 1992 Approx. Scale: 1" = 5900' Carlsbad Habitat Management Plan Total Habitat Value/Sensitivity Map TABLES TOTAL HABITAT VALUE/SENSITIVITY FREQUENCY DISTRIBUTION Value Frequency Value TOTAL Frequency 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 27 30 17 14 34 37 52 41 53 50 46 44 47 43 41 49 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 46 37 38 40 36 36 29 29 24 10 7 8 3 3 3 2 2 978 4.10 TOTAL HABITAT VALUE/SENSITIVITY - DISCUSSION The results for the total HV/HS were similar to the results for HV and HS considered separately. For this reason, further analyses of the FPAs will focus on the total HV/HS scores. These scores will also be used to determine potential wildlife corridors to link the core preserve areas. The results suggest that the City of Carlsbad has several areas with high biological value and hence high potential value as part of a preserve system. Fortunately, as illustrated in Figure 9, these areas tend to cluster in the FPAs, and thus are at least potentially available for acquisition. Because these biologically valuable areas comprise more than 6,000 acres, it is clear that only a subset of the areas with high HS/HV will be acquired for the preserves. From a purely biological perspective, the preserve lands acquisition strategy should include at least three components: • Clustered cells scoring at least 100 points should receive top priority in the preserve system. • Cells scoring 50 to 100 points that share a side with higher scoring cells also should be considered for inclusion in the core preserves, but with a lower priority. These cells may serve as buffers for the higher quality habitat and as potential corridors. 54 • As cells are considered for acquisition, potential habitat linkages between core areas should be considered. 4.11 LIMITATIONS OF APPROACH The preserve design approach taken here has some limitations. It has been noted that the sensitive species data base is not complete because not all areas of the City of Carlsbad have been surveyed. Also, the number of sensitive species not recognized by the resource agencies has grown considerably in the past few years and, thus, species considered to be sensitive now were not necessarily surveyed for in past efforts. Therefore, even for sites with good biological information, surveys for sensitive species may have been inadequate. From the perspective of sensitive species alone, a more complete data base may result in some modifications to the existing preserve planning areas in order to encompass sensitive species that were not captured in this phase of the work. Work conducted in Phase III of the HMP and beyond will in part be directed to developing a more complete sensitive species data base from ongoing and future field work. 55 SECI ON i Preserve Recommendations BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 5 PRESERVE RECOMMENDATIONS 5.1 INTRODUCTION In this section, recommendations intended to assist the City of Carlsbad in assembling a viable biological preserve system are provided. This section consists of an analysis of the proposed core preserve areas from which the ultimate preserve system will be built, identification of potential wildlife corridors that would serve to link the core areas, and an analysis of potential land uses adjacent to preserve areas in terms of their impacts and ways to minimize those impacts. The goal of this section is to provide the City of Carlsbad with the information necessary to implement a preserve land acquisition strategy. As such, specific minimal preserve boundaries are not drawn. Rather, the analysis will allow the City to choose from a menu of alternative preserve options that will result in a viable preserve system in concert with concurrent conservation efforts in the region (e.g., the North County MHCP, the Clean Water Program MSCP, and the County of San Diego OSHMP). In this way, the City will have the maximum flexibility in implementing the preserve system. 5.1.1 SIZE OF PRESERVE SYSTEM An important issue for the establishment of preserves is determining the sizes of the individual core preserves and the overall system. The solution to this depends on several factors, including the area needed to support minimum viable populations of the key species included in the preserves, the quality of the habitat preserved, connections between core preserve areas, adjacent land uses, and long-term management of the preserve system. As discussed in Section 4.2, the larger the preserves, the better, because species' extinction rates are inversely related to patch size (Diamond 1975; Wright and Hubbell 1983; Usher 1987; Soule 1991). Soule et al. (1988) suggest that habitat fragments in southern California smaller than 250 ha (617 acres) will likely lose some species. All things being equal, smaller preserves require a greater level of protection and more intense, hands-on management to remain viable (Noss 1983). Unfortunately, the fundamental biological information needed to specify the minimum areas required by key species is lacking. For this reason, the City of Carlsbad should take a conservative approach to identifying the areas targeted for acquisition and retain as much flexibility as possible in implementing the HMP. As biological information on key species (e.g., the California gnatcatcher and orange-throated whiptail) accrues, the preserve system should be fine-tuned to meet the needs of these species and maintain functional ecological systems. 5.2 POTENTIAL CORE PRESERVE AREAS In Section 4.4.1, pre- and post-gnatcatcher focused planning areas (FPAs) were described. The FPAs included undeveloped areas in the City of Carlsbad that have relatively contiguous natural habitat. It was clear that the biological preserve system would be developed from some subset of the FPAs because the best remaining habitat in Carlsbad is captured in the FPAs and much of the habitat likely would be available for acquisition. However, the amount of natural habitat in the FPAs was far more than would be feasible to acquire for the final preserve system. Upon completion of the habitat value (HV) and habitat sensitivity (HS) analyses, it was possible to further refine the FPAs. The results of this analysis yielded a set of preserve planning areas. The preserve planning areas are 56 distinguished from the FPAs in terms of the quality of habitat included. The methodology and results of this analysis are presented below. 5.2.1 METHODS In order to refine the FPAs, a simple decision rule about whether to include a specific habitat cell in the preserve planning area was employed1. Any habitat cell scoring fewer than 100 points that was not adjacent to another habitat cell scoring at least 100 points was excluded from the preserve planning area. Adjacency was defined as the habitat cell sharing at least one side with a cell scoring at least 100 points; i.e., connections at corners with cells scoring at least 100 points did not qualify a cell for inclusion in the preserve planning area. Cells scoring fewer than 100 points were included in the preserve planning area if adjacent on at least one side to a high scoring cell because they may serve as corridors between better habitat or as buffers. It is important to note that this method was used only to circumscribe potential core preserve areas and was not intended to identify wildlife corridors. The methodology to identify corridors is described below. It also is important to note that the circumscribed areas provide an artificial picture of the ultimate preserve areas, because the grid overlay was placed in an arbitrary position. The final preserve areas likely will have boundaries that follow the contours of property boundaries, vegetation, topography, and other constraints or open space plans included in development projects. The circumscribed areas described here as potential core preserve areas provide a guide to the best remaining natural habitat in Carlsbad rather than a specific delineation of where precise boundaries should fall. 5.2.2 RESULTS Separate analyses were carried out for the pre- and post-gnatcatcher listing FPAs (see Figures 5 and 6). Figures 10 and 11 show the pre-listing and post-listing preserve planning areas, respectively. Figure 10 shows the vegetation communities occurring in the pre-listing preserve planning areas. Table 9 provides the acreages by aggregated vegetation type for the pre-listing preserve planning areas. Figure 11 shows the vegetation communities occurring in the post-listing preserve planning areas. Table 10 provides the acreages by aggregated vegetation type for the post-gnatcatcher listing preserve planning areas. Within the pre- and post-California gnatcatcher listing preserve planning areas, the following percentages of native vegetation types within the City are included in the total preserve planning area: Pre Post Coastal Sage Scrub 65% 77% Chaparral 58% 73% Native Grassland 23% 27% Saltwater/Freshwater Marsh 48% 78% 1 The preserve planning areas discussed here were determined prior to minor final revisions of the vegetation map. A few cells along the boundaries of the preserve planning areas changed value in the final run of the habitat value/sensitivity analysis and would not have been included in the preserve planning areas. Changes to the preserve planning areas as a result of the vegetation revisions will be considered in Phase III of the HMP. 57 TABLE 9 ACREAGES BY AGGREGATED VEGETATION TYPES PRE-CALIFORNIA GNATCATCHER LISTING PRESERVE PLANNING AREAS Vegetation/Land Cover Within PPAs PPA 1 Pre Listing Acreages PPA 2 PPA 3 PPA 4 PPAS PPA 6 PPA 7 Not Within PPAs Coastal Sage Scrub Diegan Coastal Sage Scrub Maritime Succulent Scrub Disturbed Coastal Sage Scrub, Maritime Succulent Scrub Chaparral Southern Mixed Chaparral Chamise Chaparral Southern Maritime Chaparral Coastal Sage/Chaparral Mix Disturbed Chaparral, Southern Maritime Chaparral, Coastal Sage/Chaparral Mix Native Grassland Non-Native Grassland Disturbed Grassland 1,684 350 1,142 0 10 0 0 465 85 564 80 128 32 66 214 21 77 174 167 0 3 856 0 29 0 205 0 819 283 838 40 5 941 0 113 0 123 0 37 2 145 4 446 0 0 0 78 17 1,507 58 TABLE 9 (Continued) Vegetation/Land Cover Saltwater Marsh Freshwater Marsh Riparian Scrub Oak Woodland Sycamore Alluvial Woodland Eucalyptus Woodland Open Water Disturbed Wetland Disturbed Habitat, Active, Agriculture, Golf Course Developed TOTAL WITHIN PPAs TOTAL BY PPA TOTAL FOR CITY Pre Listing Acreages Within PPAs PPA 1 PPA 2 PPA 3 PPA 4 PPA 5 PPA 6 PPA 7 173 8 16 33 08 107 0 249 58 70 26 3 54 17 21 124 0 108 0 96 02 61 0 4 0 5 8 33 12 1,026 108 223 264 0 7 422 2 88 40 2 6 3 35 00 1,233 35 381 222 165 291 47 93 293 21 72 30 84 20 42 24 7,378 393 2,113 859 679 1,341 671 1,322 24,940 Not Within PPAs 186 219 27 241 77 102 3,311 9,898 17,563 Source: SANDAG, 7/92 59 TABLE 10 ACREAGES BY AGGREGATED VEGETATION TYPES POST-CALIFORNIA GNATCATCHER LISTING PRESERVE PLANNING AREAS Vegetation/Land Cover Within PPAs PPA 1 Pre Listing Acreages PPA 2 PPA 3 PPA 4 PPAS PPA 6 PPA 7 Not Within PPAs Coastal Sage Scrub Diegan Coastal Sage Scrub Maritime Succulent Scrub Disturbed Coastal Sage Scrub, Maritime Succulent Scrub Chaparral Southern Mixed Chaparral Chamise Chaparral Southern Maritime Chaparral Coastal Sage/Chaparral Mix Disturbed Chaparral, Southern Maritime Chaparral, Coastal Sage/Chaparral Mix Native Grassland Non-Native Grassland Disturbed Grassland 1,955 469 1,439 35 0 10 0 588 91 582 0 125 228 190 130 214 24 77 194 167 0 3 8% 0 39 0 306 0 27 548 164 540 13 6 1,562 0 113 0 159 0 189 3 177 4 446 0 0 0 478 16 887 60 TABLE 10 (Continued) Vegetation/Land Cover Saltwater Marsh Freshwater Marsh Riparian Scrub Oak Woodland Sycamore Alluvial Woodland Eucalyptus Woodland Open Water Disturbed Wetland Disturbed Habitat, Active, Agriculture, Golf Course Developed TOTAL WITHIN PPAs TOTAL BY PPA TOTAL FOR CITY Within PPAs PPA 1 278 8 354 58 136 0 102 0 1,062 108 124 40 1,466 35 408 21 9,396 393 24,940 Pre Listing Acreages PPA 2 PPA 3 PPA 4 PPAS PPA 6 PPA 7 16 137 0 8 107 1 83 87 5 54 17 51 119 0 96 03 5 28 11 8 33 17 258 265 0 7 422 2 2 42 4 35 00 447 341 190 291 47 167 95 76 105 20 42 48 2,446 1,708 854 1,341 671 1,983 Not Within PPAs 80 114 15 200 41 66 3,078 9,783 15,544 Source: SANDAG, 7/92 61 Pre Post Riparian Scrub 53% 76% Oak/Sycamore Alluvial Woodland 82% 90% Open Water 97% 96% With the exception of native grassland, and salt and freshwater marsh under the pre-listing scenario, the majority of native habitat within the City is included in the preserve planning areas. Salt and freshwater marsh, however, already have statutory protection. The preserve planning area analysis allows for the designation of those areas in Carlsbad that constitute the best remaining habitat within the City. The fact that the City retains more than 7,300 acres of good habitat under the pre-gnatcatcher listing alternative and nearly 9,400 acres under the post-gnatcatcher listing alternative indicates that the City has an excellent opportunity to assemble a biological preserve system. Each preserve planning area is considered in detail below. Sensitive Species Figure 4 shows the distribution of sensitive species in the City of Carlsbad and Section 2 provides a detailed discussion of each species. Information concerning sensitive species was gathered from existing EIRs, other environmental documents, and discussions with local experts. Tables 11 and 12 provide a matrix of records for sensitive species by preserve planning area for both the pre- and post- listing scenarios, respectively. Under the pre-listing scenario, preserve planning areas 2, 4, 5, and 7 contain a good diversity of both sensitive wildlife and plant species. Under the post-listing scenario, the results are similar, with the exception that preserve planning area 3 captures much greater diversity, because its area is greatly expanded, from 859 acres to 1,708 acres. Tables 11 and 12 list all the sensitive species recorded from the preserve planning areas based on information available for the present study. There certainly are more instances of sensitive species occurring in these areas than presented here. For example, the Belding's Savannah sparrow likely is much more widespread in the salt marsh habitat around the lagoons than reflected in these data. Not all of the sensitive wildlife and plant species occurring in Carlsbad are captured in the preserve planning areas. These omissions may reflect gaps in the ultimate protection of these areas. On the other hand, existing protected lands or designated open space may provide protection for some of these resources. Resolution of such questions requires performance of a "gap analysis", which will be performed in Phase III of the HMP work plan. 62 TABLE 11 PRE-CALIFORNIA GNATCATCHER LISTING PRESERVE PLANNING AREA SENSITIVE SPECIES RECORDS Preserve Planning Area3 Species 123456 7 WILDLIFE Belding's Savannah Sparrow California Gnatcatcher l& 2 6 13 35 California Least Tern Least Bell's Vireo Light-footed Clapper Rail Orange-throated Whiptail 3 2 San Diego Horned Lizard 2 PLANTS Ashy-spike Moss X° XX X California Adolphia X XX Del Mar Manzanita X X Engelmann Oak X X Orcutt's Brodiaea San Diego Golden-star X San Diego Thorn-mint Spiny Rush XX X Summer-holly X XX Wart-stemmed Ceanothus X X Western Dichondra X X a Based on existing available data. New surveys were not performed in potential PPAs b Indicates number of records c Indicates presence 63 TABLE 12 POST-CALIFORNIA GNATCATCHER LISTING PRESERVE PLANNING AREA SENSITIVE SPECIES RECORDS Preserve Planning Area Species 123456 7 WILDLIFE Belding's Savannah Sparrow 1 California Gnatcatcher 16 6 7 13 40 California Least Tern 1 Least Bell's Vireo 1 Light-footed Clapper Rail 1 Orange-throated Whiptail 3 2 San Diego Horned Lizard 2 PLANTS Ashy-spike Moss California Adolphia Del Mar Manzanita Engelmann Oak Orcutt's Brodiaea San Diego Golden-star San Diego Thorn-mint Spiny Rush Summer-holly Wart-stemmed Ceanothus Western Dichondra X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Sensitive species known to occur outside of the pre-listing preserve planning areas include: Belding's Savannah Sparrow Light-footed Clapper Rail California Least Tern Least Bell's Vireo Chocolate Lily Cliff Spurge Del Mar Mesa Sand Aster San Diego Marsh Elder Thread-leaved Brodiaea The post-listing preserve planning areas capture more sensitive species, because they are larger. However, sensitive species known to occur outside of the post-listing preserve planning areas include: 64 Chocolate Lily Cliff Spurge Del Mar Mesa Sand Aster San Diego Marsh Elder Thread-leaved Brodiaea Fortunately, most of the species not captured by the preserve planning areas are plants that could be preserved by acquiring small areas of land or implementing some type of localized protection program (conservation easements, fencing, etc.). Based on available information and discussions with local experts, it is estimated that there are between 113 and 166 California gnatcatcher pairs in the City of Carlsbad (P. Mock, pers. comm.). The 113 known to the City probably underestimate the total, because some coastal sage scrub habitat is unsurveyed. Of the known gnatcatchers in the City, the pre-listing preserve planning area includes approximately 72 pairs and the post-listing preserve planning area includes approximately 82 pairs. The remaining known pairs tend to be scattered among fragments of coastal sage scrub habitat throughout the City. Some of these pairs inhabit areas already protected as open space or along utility easements. Thus, most of the known gnatcatchers subject to the greatest risk are included in the preserve planning areas. These gnatcatchers also tend to be clustered wherever they occur. Therefore Carlsbad will have the opportunity to make a significant contribution to the conservation of gnatcatchers on a regional basis. Each of the preserve planning areas are discussed in detail below. Pre-Gnatcatcher Listing Preserve Planning Areas Preserve Planning Area 1 (PPA1) PPA1 consists primarily of the Buena Vista Lagoon in its western portion and Buena Vista Creek in its eastern portion. This 393-acre area lies at the northwestern border of Carlsbad, and is bounded by State Highway 78 on the north and urban development on the south. The dominant habitat type is the open water of the lagoon (108 acres). The eastern portion supports riparian scrub and non- native annual grassland. The planning area also includes some small patches of disturbed habitat. As a potential preserve area, PPA1 contains highly sensitive wetland habitats. The lagoons and salt marsh and freshwater marsh habitats are statutorily protected from development under Section 404 of the federal Clean Water Act and Section 1600 of the California Fish and Game Code. Furthermore, Buena Vista Lagoon is managed as an ecological reserve area by CDFG and is therefore already under state protection and management. The open water habitat of the lagoon supports a variety of fishes and provides foraging habitat for numerous waterfowl, diving birds, and shorebirds. Sensitive wildlife species likely to occur in the lagoon or the associated salt marsh include the Belding's Savannah sparrow, light-footed clapper rail, California least tern, and salt-marsh skipper. Freshwater marsh provides habitat for two sensitive plant species: spiny rush and San Diego marsh elder. Carlsbad will need to manage the watershed and tidal influences that affect the viability of the lagoon, as well as Batiquitos and Agua Hedionda lagoons. While the lagoons and marsh habitat currently have statutory protection, and thus do not require acquisition, the HMP should include provisions for preserving or enhancing the quality of these valuable resources. A concern recently voiced is the enforcement of runoff control measures to reduce sedimentation into the lagoons, and in particular 65 Batiquitos. Another concern is to manage the watersheds of the lagoons to ensure a balance between freshwater and tidal influences on the fragile lagoon ecosystem. Preserve Planning Area 2 (PPA2) PPA2 contains 2,113 acres generally located east of Tamarack Avenue, northeast of El Camino Real, and north of Palomar Airport Road. The dominant vegetation in this area is coastal sage scrub and chaparral (1,114 acres), with relatively large patches of disturbed habitat interspersed with the sage scrub and chaparral. This area supports one of the two remaining areas in Carlsbad with large, contiguous stands of coastal sage scrub. Other notable features in PPA2 include Lake Calavera and Squires Dam, riparian scrub, and well developed oak woodlands in the southern portion of the area. The important habitat in PPA2 occurs in three large blocks: around Lake Calavera, the block of coastal sage scrub east of Rancho Carlsbad Golf Course, and the block of coastal sage scrub and chaparral around Agua Hedionda Creek in the southeast portion of the planning area. The northern and southern portions contain the greatest diversity and density of sensitive species. These areas should be the focus of future acquisitions. Ideally, these sub-areas would be acquired as large habitat blocks connected by wildlife corridors. The woodland along Agua Hedionda Creek would provide a potential connection between the more southern habitat blocks. PPA2 supports substantial coastal sage scrub (550 acres) and the second greatest concentration of gnatcatchers in the City, as well as several other sensitive species (Table 12). Portions of PPA2 will serve as a key part of the preserve system . Preserve Planning Area 3 (PPA3) PPA3 is an 859-acre area primarily comprised of Agua Hedionda Lagoon (264 acres) in the west portion. The area lies south of Tamarack Avenue, north of Palomar Airport Road, and is bisected by Hidden Valley Road. The eastern portion of PPA3 supports riparian scrub and relatively small areas of coastal sage scrub in the eastern portion. The greatest value of PPA3 is the lagoon and riparian scrub, because these areas already have statutory protection. The remaining habitat in PPA3 is marginal: the patches of coastal sage scrub and chaparral would become fragmented with eventual development to the north and northeast (e.g., Evans Point) and thus will not connect with other scrub or chaparral in the City available for acquisition under the pre-listing scenario. Preserve Planning Area 4 (PPA4) PPA4 is a 679-acre area bordered on the north by Palomar Airport Road, on the east by El Camino Real, and on the north and south by development. This area contains patches of maritime succulent scrub in the western portion, chaparral in the central and eastern portion, and some smaller areas of riparian scrub and oak woodland. Much of PPA4 supports non-native grassland and disturbed habitat (310 acres). The coastal sage scrub in PPA4 borders relatively large stands of sage scrub to the north and south, but these areas are rapidly urbanizing. It is unlikely that the coastal sage scrub remaining in this area will retain high biological value over the years unless adjacent development projects include preservation of substantial areas of coastal sage scrub. The chaparral in the central and eastern portion of PPA4 is intact and connects to some large patches of chaparral to the east in PPA5. The chaparral-oak woodland mosaic in the eastern part of the area is the best habitat in PPA4. The primary value of PPA4 is that it contains a variety of sensitive plants associated with maritime succulent scrub. Fortunately these patches of habitat can be preserved without requiring acquisition of large areas or connections to other habitat, since the primary purpose will be to preserve sensitive vegetation. 66 Preserve Planning Area 5 (PPA5) PPA5 contains 1,341 acres. The area is bounded on the north by Palomar Airport Road, on the south by Alga Road, on the west by El Camino Real, and on the west by the City of San Marcos. PPA5 supports a patchwork of coastal sage scrub, chaparral, oak woodland, and riparian scrub. The dominant vegetation, however, is non-native grassland (446 acres). The coastal sage scrub and chaparral habitats in PPA5 are much more fragmented than the habitats in PPA2 or PPA7. However, the coastal sage scrub on the eastern boundary of PPA5 connects with substantial coastal sage scrub in the City of San Marcos. Despite the apparent fragmentation of habitat in PPA5, this planning area supports at least 13 gnatcatcher pairs and a variety of sensitive plants (Table 12). PPA5 also would serve an important function as a link between the coastal sage scrub and chaparral habitats in PPA2 and PPA7. Potential corridors exist along the western edge of the area, just to the east of the western edge, and in the eastern part of PPA5. The habitat along the western edge, which parallels El Camino Real, consists primarily of chaparral and does not connect to other large chaparral patches. The more interior corridor is comprised of discrete but proximate patches of coastal sage scrub and riparian scrub. This potential corridor may function for coastal sage scrub species such as the gnatcatcher. The eastern corridor would require the assemblage of small fragmented patches of coastal sage scrub and riparian habitat to serve as a conduit for coastal sage scrub species. The most promising habitat link lies to the east and would connect with coastal sage scrub habitat in San Marcos (see discussion of wildlife corridors below). Preserve Planning Area 6 (PPA6) PPA6 consists of the Batiquitos Lagoon area and comprises 671 acres. This area is bordered on the south by La Costa Avenue and the City of Encinitas, on the east by El Camino Real, and on the north by residential development and disturbed habitat. PPA6 is dominated by the open water habitat of the lagoon, with salt and freshwater marsh along the edges (529 total acres). As described above for the Buena Vista Lagoon, biologically this habitat is extremely valuable and sensitive. Sensitive species likely to occur also are as described above. The CDFG manages the Batiquitos Lagoon as an ecological preserve, and thus it is already under state protection. Preserve Planning Area 7 (PPA7) PPA7 consists of a 1,322-acre area located in the southeastern portion of the City. The property primarily is owned by the Fieldstone Company. This area is bisected by Rancho Santa Fe Road, bordered on the north by Alga Road, and on the southeast by the City of Encinitas. PPA7 supports the largest contiguous stand of coastal sage scrub in the City of Carlsbad and currently provides habitat for at least 35 gnatcatcher pairs. The remaining habitat in the PPA7 mostly is comprised of chaparral (205 acres) with smaller patches of non-native grassland and disturbed habitat in the central portion. There also are small areas of riparian scrub and a small area of open water. In addition to gnatcatchers, PPA7 supports a variety of sensitive plants. PPA7 will be a significant part of the preserve system because of its coastal sage scrub habitat. In coordination with the USFWS and the City of Carlsbad, the Fieldstone Company has a pre-listing Habitat Conservation Plan (HCP) proposal for preservation of nearly 500 acres of coastal sage scrub and gnatcatcher habitat as mitigation for their residential development project and the widening of Rancho Santa Fe Road. This preserved habitat will be a keystone of the City's preserve system and will provide a link to other gnatcatcher populations and coastal sage scrub in the City of Carlsbad, as well as with coastal sage scrub habitat outside of the City. This regional linkage will be essential for the viability of the 67 Carlsbad gnatcatcher population and will contribute to the viability of the regional gnatcatcher population. Post-Gnatcatcher Listing Preserve Planning Areas The post-listing preserve planning areas are larger than the pre-listing areas because they include undeveloped areas that have an approved tentative map. However, there is a great degree of concordance between the two sets of planning areas. In this section, significant differences in the preserve planning areas are noted. Preserve Planning Area 1 (PPA1) Same as pre-listing PPA1. Preserve Planning Area 2 (PPA2) PPA2 generally is the same as the pre-listing PPA2. The post-listing PPA2 contains 2,446 acres generally located east of Tamarack Avenue, northeast of El Camino Real, and north of Palomar Airport Road. The dominant vegetation in this area is coastal sage scrub and chaparral (1,261 acres), with relatively large patches of disturbed habitat interspersed with the sage scrub and chaparral. The post-listing scenario differs from the pre-listing scenario primarily in the addition of a large area of coastal sage scrub in the northern portion. While addition of this area increases the amount of coastal sage scrub in PPA2, there are no records of gnatcatchers in the added habitat. This area does, however, support a substantial population of California adolphia. Preserve Planning Area 3 (PPA3) The post-listing PPA3 extends the planning area well to the north and south of the pre-listing planning area. PPA3 contains 1,708 acres including the Agua Hedionda Lagoon, marsh habitat, a mosaic of coastal sage scrub, chaparral, non-native grassland, and disturbed habitat in the northern portion. The value of the post-listing PPA3 is significantly improved over the pre-listing planning area via the addition of substantial sage scrub and chaparral. The number of sensitive wildlife and plant species captured greatly increases by the expansion of PPA3 (Table 12). Also, the expanded area creates more opportunities for connecting the adjacent preserve planning areas. Preserve Planning Area 4 (PPA4) The post-listing PPA4, at 854 acres, is somewhat larger than the pre-listing PPA4, with the addition of some coastal sage scrub and non-native grassland in the northwest corner and some chaparral and eucalyptus stands in the southern part. However, much of the habitat in PPA4 is non-native grassland and disturbed habitat. With the additional habitat in the north, PPA4 could serve as a link between PPA3 and PPA6. As described above, the primary value of PPA4 is the large number of sensitive plants that occur in the area. Preserve Planning Area 5 (PPA5) The post-listing PPA5 is the same as the pre-listing PPA5. Preserve Planning Area 6 (PPA6) The post-listing PPA6 is the same as the pre-listing PPA6. 68 Preserve Planning Area 7 (PPA7) The post-listing PPA7 encompasses the pre-listing PPA7 and adds habitat in the extreme southeast corner of the City for a total of 1,983 acres. As described above, PPA7 includes the largest single area of continuous coastal sage scrub in the Carlsbad. The areas to the south add some areas of chaparral, coastal sage scrub, and riparian scrub, but the additional area mostly supports non-native grassland. However, the number of known gnatcatchers in PPA7 is 40 and the number of sensitive plants increases as well (Table 12). The addition of these areas also provides the potential for linking PPA6 (Batiquitos Lagoon) and PPA7 via riparian scrub habitat. 5.3 POTENTIAL WILDLIFE CORRIDORS As discussed in Section 4.2.3, the degree of isolation of individual preserves is an important design consideration, because one of the functions of a preserve system is to promote regional biological diversity. For maintenance of biodiversity, it is assumed that at least modest levels of migration between preserves via habitat linkages or wildlife corridors must occur to prevent local extinctions within the individual preserves. Some of the key factors for wildlife corridors to function effectively are: (1) isolated preserves must be as close together as possible to facilitate exchange of individuals between subpopulations (Diamond 1975; Wilson and Willis 1975); (2) corridors must be wide enough to overcome edge effects; (3) corridors must possess appropriate habitat and cover for the key species expected to travel through them; and (4) corridors must have as few turns or other barriers to movement as feasible (Soule and Gilpin 1991). 5.3.1 METHODS Potential wildlife corridors linking the preserve planning areas in Carlsbad were identified by examining the vegetation map with the pre- and post-listing planning area overlays (see Figures 10 and 11). Those areas identified as possible corridors provide either the shortest physical link between two preserve planning areas or areas with continuous or nearly continuous habitat that wildlife could use for movement and cover. In several cases, the corridors cross major roadways such as El Camino Real or Palomar Airport Road, because there is no other way of connecting preserve areas. In these cases, the habitat of the planning areas generally abuts the road. These kinds of corridors will be of limited value, however, because they would preclude use by certain species. Not all of the corridors identified will be functional or desirable. In some cases, a corridor may effectively link two areas, but be non-functional because the two preserves support different species. Such a corridor could even be detrimental in the long term because animals using it may be at greater risk to predation resulting from edge effects, relative lack of cover or refuge, and unfamiliarity with the area. The corridor, in essence, acts as a "sink" for individuals and serves to reduce numbers in the feeder populations. The dashed lines signifying wildlife corridors in Figures 10 and 11 represent strips 375 feet wide. Ideally, corridors should be at least 1,000 feet wide to provide adequate cover and space for the wildlife. However, the minimum width will depend on the type of habitat, the length of the corridor, and the amount of cover provided. (See discussion of buffers and distance setbacks provided in Section 4.2.4.) It is important to keep in mind that the corridors discussed below refer only to potential connections between preserve planning areas. Because the preserve planning areas represent the best remaining contiguous natural habitat in the City, the proposed corridors almost always will consist of more degraded or fragmented habitat. Also, as the preserve planning areas are further refined, corridors within the preserve planning areas will become important (i.e., local or internal corridors). The same 69 principles discussed below for the corridors will apply to the local corridors. Fortunately, because these corridors would be developed in habitat considered of high biological value, it should be easier to design connections that contain appropriate habitat and adequate space. 5.3.2 RESULTS Pre-Gnatcatcher Listing Wildlife Corridors Figure 10 illustrates the potential wildlife corridors under the pre-listing scenario. For brevity, the wildlife corridors are coded by the preserve planning areas they connect. For example, the wildlife corridor between PPA1 and PPA2 is coded as WC1-2. Where there are multiple corridors connecting two preserves, a capital letter is added to the code to distinguish the different connections. WC1-2 is approximately 2,000 feet in length and crosses patches of coastal sage scrub. The value of this corridor is questionable because it connects the coastal sage scrub in PPA2 with non-native grassland in PPA1, and thus would not serve a useful function for coastal sage scrub species. This is an example of a wildlife corridor that could function as a sink for some species. Larger mammals, such as coyotes, foxes, skunks or raccoons probably would use this corridor. WC2-5A bridges a gap of approximately 2,600 feet between chaparral north of Palomar Airport Road in PPA2 and chaparral to the south in PPA5. The corridor crosses Palomar Airport Road and disturbed habitat. The major impediment posed along this corridor is the roadway. Palomar Airport Road receives heavy traffic flow during the day, which would preclude diurnal movements of wildlife. Species capable of moving at night, such as coyotes, foxes, raccoons, skunks, and perhaps bobcats, may be able to cross the roadway without great risk. Rabbits and rodents also may effectively use this corridor. WC2-5B connects PPA2 and PPA5 via strips of coastal sage scrub and disturbed habitat approximately 3,700 feet long and about 700 feet wide. It ties in oak woodland in PPA2 with a patch of coastal sage scrub in PPA5. This corridor could function for larger species as well as small coastal sage scrub species. The major obstacle in this corridor is Palomar Airport Road, which may inhibit or preclude movement by some species as described for WC2-5A WC4-5 connects the east part of PPA4 with the west part of PPA5. This corridor would connect patches of chaparral in the two preserve planning areas and may link areas of oak woodland in the two preserve areas. The major drawback to this linkage is that it crosses El Camino Real, which poses an obstacle to smaller and diurnal species. Larger nocturnal species likely use this corridor without much difficulty. As discussed above, however, the main biological value of PPA4 comes from sensitive plants species. The wildlife in PPA4 is threatened by urbanization to the north. Therefore, a wildlife corridor linking PPA4 and PPA5 probably is of low priority. WC4-6 connects the southern portion of PPA4 with the northern portion of PPA6 at Batiquitos Lagoon. The corridor crosses Alga Road and extends approximately 5,000 feet through disturbed and eucalyptus woodland habitat. Because of the lack of cover and the obstacle posed by Alga Road, use of the corridor would be limited to crepuscular and nocturnal movements by species such as skunks, foxes, raccoons, coyotes, and perhaps bobcats. The eucalyptus woodland provides habitat for raptors and other birds. WC5-7A is located east of the City boundary and connects PPA5 with PPA7. It extends approximately 6,000 feet, of which 4,500 feet is coastal sage scrub, 1,100 feet is riparian scrub, and 400 feet is developed. This may be a critical link between the coastal sage scrub habitat and coastal sage scrub species in the southeast portion of Carlsbad and that in the City of San Marcos. 70 WC5-7B is a 3,300-foot corridor approximately 300-400 feet wide that connects PPA5 and PPA7. It follows an existing powerline easement. The corridor primarily supports non-native grassland and probably serves as a corridor for larger species such as coyotes, foxes, and skunks. It would not be particularly useful for coastal sage scrub species because there is relatively little scrub habitat in PPA5. Small species that use non-native grasslands, such as rodents and rabbits could use this corridor as well. WC5-6,7 comprises La Costa Golf Course. It connects PPA5 and PPA7 and links with PPA6 via a strip of marsh and disturbed habitat. While golf courses do not serve as corridors for many sage scrub and chaparral species, larger mammalian species such as coyotes and rabbits will use such areas for movements. The connection to PPA6 would provide a corridor for species using Batiquitos Lagoon. Post-Gnatcatcher Listing Wildlife Corridors WC1-2 is the same as the pre-listing WCl-2. WC2-3A is a 3,700-foot corridor that connects PPA2 and PPA3. This corridor includes coastal sage scrub, non-native annual grassland, and disturbed habitat. It links coastal sage scrub habitat in PPA2 with riparian scrub, eucalyptus woodland, and disturbed habitat in PPA3. There are areas of chaparral and coastal sage scrub in the northern part of PPA3 that potentially could link with PPA2 habitat via this corridor. The drawback to this corridor is that it crosses El Camino Real below the intersection of El Camino and Tamarack Avenue, thus precluding or inhibiting the movement of diurnal and smaller species that would have difficulty safely crossing a four-lane thoroughfare. WC2-3B is a 4,500-foot corridor that connects PPA2 and PPA3 just to the east of WC2-3A via riparian scrub. This corridor, although lengthy, directly connects coastal sage scrub in PPA2 with riparian scrub on PPA3. Again, however, the corridor must cross El Camino Real, thus providing an obstacle to the movement of many animals. The other main disadvantage of this corridor is that it is rather narrow ~ generally less than 200 feet wide and is adjacent to disturbed habitat. WC2-3C is a 1,500-foot corridor that connects riparian scrub in PPA2 with eucalyptus woodland in PPA3. A patch of chaparral lies southwest of the eucalyptus. This may be an effective corridor for some avian species that can use the riparian scrub and oak woodland to the east in PPA2 and also utilize the eucalyptus woodland and riparian habitats in PPA3. As with the other corridors connecting PPA2 and PPA3, El Camino Real provides an obstacle to movement between the two areas, although it would not be an obstacle to many avian species. WC2-5A is the same as the pre-listing WC2-5A. WC2-5B is the same as the pre-listing WC2-5B. WC3-4 is a 500-foot corridor between PPA3 and PPA4. This corridor probably would not serve an important function because it is interrupted by Palomar Airport Road. Also, the western end of PPA4 has questionable value as a wildlife preserve because is consists of a patchwork of coastal sage scrub, non-native grassland, and disturbed habitat. WC4-5 is the same as the pre-listing WC4-5. WC4-6 is the same as the pre-listing WC4-6. WC5-7A is the same as the pre-listing WC5-7A. 71 WC5-7B is the same as the pre-listing WC5-7B. WC5-6,7 is the same as the pre-listing WCS-6,7. WC6-7 is a 3,000-foot corridor that connects the eastern end of PPA6 and the western end of PPA7. The corridor supports riparian scrub that is 500-700 feet wide. This corridor would serve to connect marsh areas in PPA6 with riparian scrub in PPA7. An obstacle for this corridor is the La Costa Avenue-El Camino Real intersection area. This corridor likely would be effective for avian species that use the marsh/riparian habitats, but limited for small mammals. WC7-7A is an 1,100-foot corridor that connects two parts of PPA7. The corridor supports non-native grassland and connects non-native grassland areas in the two parts of PPA7. There also are some patches of coastal sage scrub, riparian scrub, and chaparral near the corridor connection that potentially could benefit from the linkage. W7-7B is a 1,500-foot corridor that connects two parts of PPA7. The corridor contains disturbed habitat and non-native grassland. 5.4 CONCEPTUAL PRESERVE SYSTEM Under the City of Carlsbad Draft Comprehensive Open Space and Conservation Resource Management Plan, dated January 3, 1992, three existing preserves are present within the City: Batiquitos Lagoon, Buena Vista Lagoon, and the University of California Reserve. The recent conservation proposal between the City, Fieldstone, and the USFWS concerning gnatcatchers and coastal sage scrub would establish a fourth preserve of nearly 500 acres in the vicinity of Rancho Santa Fe Road. Assuming that the lagoons and associated marsh/wetland habitat, riparian scrub and woodland habitat, and the Fieldstone site have protected status, approximately 2,500 acres of habitat in the City is protected. This does not include areas already under City protection provided by General Plan and zoning controls, such as hillsides, steep slopes, canyons, or areas identified as part of the City trails system. Those protected lands still must be added to the information base to identify valuable, yet unprotected, lands. The intent of this report is to provide the City of Carlsbad with the requisite biological information to supplement the natural resources already under protection in the City. As such, the information provided in the form of the rated habitat cells, preserve planning areas, and potential wildlife corridors should provide the City with the basic information needed to guide future resource planning. It is recommended that the City consider acquisition of at least two or three additional habitat areas to develop a complete preserve system. The best remaining habitat areas in the City are located around the western end of Lake Calavera and the riparian scrub running south from the lake, the Agua Hedionda Creek area south of Squires Dam, the western portion of PPA5, and the central portion of PPA4. Ideally, the Lake Calavera, Agua Hedionda Creek, and PPA5 areas could be linked with wildlife corridors. Local corridors within PPA2 have not been specifically identified. The corridor between PPA2 and PPA5 is WC2-5A. PPA5 and PPA7 could be linked with WC5-7B. As described above, the central portion of PPA4 supports maritime succulent scrub and a variety of sensitive plant species. These areas could be preserved effectively without additional wildlife corridors. It is important to note that these recommendations are very general. It is not possible at this time to specify parcels for acquisition. Several steps are necessary before the City can begin acquiring habitat for the preserve system, including: 72 • Identification of habitat areas already under public ownership or part of the Citywide trails system (i.e., the gap analysis) • Identification of habitat areas protected as open space in existing and proposed development projects • Analysis of how public and protected habitat relates to unprotected core preserve areas identified in this document • Targeting of specific acquisition areas based upon the above analyses • Focused biological field surveys of targeted areas to validate the habitat analysis presented here and to provide current information on general and sensitive resource diversity and abundance 5.5 COMPATIBLE LAND USE ANALYSIS One of the difficult challenges for designing and implementing a preserve system in the City of Carlsbad will be to specify appropriate buffers and setbacks between development and preserve areas, as well as to define acceptable human uses of preserve areas. A discussion of buffers and setbacks is presented in Section 4, along with some recommendations relating to different habitat types. These recommendations are based on guidelines from the San Diego County RPO and a separate set of guidelines from PSBS. There are very little data on the impacts of development on preserve areas. One point of general agreement, however, is that buffers and setbacks should not be considered as part of the preserve area. These areas will certainly be degraded by human related activity. Researchers presently are conducting studies on the "natural/urban interface" and some guidelines should be forthcoming in the next few years (e.g., Scott 1992; Savaujot 1992). In the absence of quantitative data on impacts by development, there are a few general guidelines that should be followed in delineating preserve boundaries. These guidelines relate to the physical features of the landscape and planned uses in developed areas. With regard to physical features, vegetation and topography can play an important role in how well a natural area is protected by affecting the level of public access to a natural area. In the absence of an established trail system, dense vegetation (e.g., chaparral, coastal sage scrub, or wetland habitat) can provide barriers to access by both humans and pets. Likewise, a preserve boundary on a ridgeline surrounded by steep slopes can restrict access to the preserved area. In natural areas used by the public, low wooden fencing or planting of shrub species, such as ceanothus or cactus, can serve to limit trespass into sensitive areas. That is, most people choose the path of least resistance, and few are likely to make the effort to gain access to rugged or densely vegetated areas. Recreation activities such as hiking, jogging, walking dogs, and mountain biking should be limited to specified trails and rigorously enforced. These activities, however, may not be appropriate for some preserved areas. The general idea is to create a preserve system where easy public access is restricted either by natural or artificial physical features. Such a benign approach (as opposed to wire fencing, heavy patrol, etc.) is preferable because of the cost savings and the public's perception of the resource as available for public enjoyment. Development adjacent to preserve areas poses varying degrees of risk to them. Medium and high density residential development probably poses the greatest risk, because of the sheer number of people, noise, lighting, use of nearby open space for recreation, pets, human-commensal species (e.g., 73 starlings and house sparrows that compete with native species for nesting areas and other resources), arson and accidental fires, and trash dumping. Preserve areas near residential developments will require the greatest amount of buffering either through distance, vegetation, topography, or fencing. Commercial development poses less of a risk to natural open space because of the limited time people use these areas, the absence of children, and the absence of pets. The most compatible land uses include active recreation areas such as parks, athletic fields (although nighttime lighting may be a problem), golf courses, and active agricultural uses. The greatest risk posed by these uses would be maintenance operations, such as the use of chemicals on maintained turf or crops. Also, control of runoff from cultivated areas is an important issue. A final, and very difficult issue, is that of itinerant worker camps scattered throughout the drainages and canyons of Carlsbad. These camps are located in some of the most sensitive habitats in the City (e.g., oak woodlands and riparian areas or any areas with heavy canopy cover and an open understory). The presence of the camps has seriously degraded these habitats because of trash and garbage, trampling of vegetation, and unsanitary living conditions (e.g., open latrine areas). Ultimately, the City will have to address this problem if these sensitive areas are to be preserved. Also, many of the areas used by the itinerant workers constitute important wildlife corridors and habitat linkages. The presence of people in these areas certainly disrupts their use by wildlife. 5.6 CONCLUSION The City of Carlsbad has the opportunity to develop a preserve system to conserve a variety of general and sensitive biological resources. This analysis provides the biological information necessary for implementing a preserve system within the City that will integrate with regional conservation planning efforts. It is anticipated that the City can effectively develop a preserve system using the information provided in this document, along with additional information regarding land use and public and private property ownership in the City. This document is a fundamental step toward achieving that goal. 74 SECI ON Acknowledgements X BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 6 ACKNOWLEDGEMENTS Completion of the Biological Resources Inventory and Analysis phase of the Carlsbad Habitat Management Plan was the joint effort of many participants. The HMP Advisory Committee is to be commended for their faithful attendance and participation at the monthly meetings. Rick Alexander of Consultants Collaborative, Inc. provided excellent leadership and guidance in his role as chair of the committee. Don Rideout and Michael Holzmiller of the City of Carlsbad were critical to the success of the work through their provision of City resources. Bob Parrott, Paula Cunningham, and Sue Carnevale of SANDAG provided GIS services, and Bob wrote the computer program for the habitat quality analyses. Also important to the success of this project were numerous property owners and their consultants who provided additional information and corrections to the biological resources data base. Finally, we thank the many reviewers who provided valuable comments on the draft document. The following are the biological consultant team members: H. Lee Jones, Ph.D. - Project Director, Michael Brandman Associates Allison Alberts, Ph.D. -- Preserve Design Specialist, Center for the Reproduction of Endangered Species, Zoological Society of San Diego Philip R. Behrends, Ph.D. -- Project Manager, Biologist, Dudek & Associates Nancy Bell-Gallagher -- Graphic Artist, Michael Brandman Associates John W. Brown, Ph.D. -- Biologist, Dudek & Associates Martie A. demons -- Graphic Artist, Dudek & Associates Michael Evans -- Natural Resources Consultant Sarah A. Flick -- Botanist, Michael Brandman Associates Tonette S. Foster -- Word Processing, Administrative Assistant, Dudek & Associates Marcia McRae -- Word Processing, Administrative Assistant, Michael Brandman Associates Gregory Pregill, Ph.D. -- Sensitive Amphibians and Reptiles, San Diego Natural History Museum Fran Saveriano - Regional Business Manager, Michael Brandman Associates Wayne D. Spencer, Ph.D. -- Biologist, Michael Brandman Associates Fred T. Sproul -- Sensitive Plant Species, Plant Ecology Harold (Howie) Wier - Biologist, Dudek & Associates 75 SECT ON 7 Literature Cited BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN SECTION 7 LITERATURE CITED Alberts, A. C, A. D. Richman, D. Tran, R. Sauvajot, C. McCalvin and D. T. Bolger. (In preparation). Effects of Habitat Fragmentation on Species Diversity of Native and Exotic Plants in Southern California Coastal Scrub. In J. E. Keely (ed) The Interface Between Ecology and Land Development in California. Based on a paper presented at the Southern California Academy of Sciences Annual Meeting, Occidental College, May 1-2, 1992. Atwood, J. L. 1990. Status Review of the California Gnatcatcher (Polioptila californica). Unpublished technical report, Manomet Bird Observatory, Manomet, Massachusetts. Bauder, E. T. 1986. San Diego vernal pools. Recent and projected losses; their condition; and threats to their existence, 1979-1990. Vols. 1 & 2. Report and Appendices 1-9. Prepared for the California Department of Fish and Game, Endangered Plant Project. Beauchamp, R. M. 1986. A Flora of San Diego County, California. Sweetwater Press, National City, California. Block, W., M. Morrison, and J. Verner. 1990. Widlife and oak-woodland interdependency. Fremontia 18:72-76. Blouin, M. S. and E. F. Conner. 1985. Is there a best shape for nature preserves? Biological Conservation 32: 277-288. Boecklen, W. J. 1986. Optimal design for nature reserves: consequences of genetic drift. Biological Conservation 38: 323-338. Boecklen, W. J. and G. W. Bell. 1987. Consequences of faunal collapse and genetic drift for the design of nature reserves. Pages 141-149 in D. A. Saunders, G. W. Arnold, A. A. Burbridge and A. J. M. Hopkins, (eds). Nature Conservation: The Role of Remnants of Native Vegetation. Surrey Beatty, Australia. Bond, S. I. 1977. An annotated list of the mammals of San Diego County, California. Trans. San Diego Soc. Nat. Hist. 18: 229-248. Bowman, R. H. 1973. Soil Survey of San Diego Area, California, Part 1. United States Department of Agriculture, Soil Conservation Service and Forest Service. 104 pp. Brown, J. W. 1981. The wandering skipper: at home on the coastal salt marsh. Environment Southwest 492:26. Brown, J. W. and W. W. McGuire. 1983. A new subspecies of Euphyes vestris (Boisduval) from Southern California (Lepidoptera: Hesperiidae). Trans. San Diego Soc. Nat. Hist. 20: 57-68. Brown, J. W. 1991. Sensitive and declining butterfly species in San Diego County, California. Manuscript. Available from Dudek and Associates, Inc. 20 pp. Burkey, T. V. 1989. Extinction in nature reserves: the effect of fragmentation and the importance of migration between reserve fragments. Oikos 55: 75-81. 76 Busnardo, M. 1989. The autecology of Panoquina errans (Lepidoptera: Hesperiidae): preliminary field and laboratory observations. Tijuana Estuary Restoration/Enhancement Project, Spring, 1989. 6 pp. + maps. Carlsbad, City of. 1992. Draft Comprehensive Open Space and Conservation Resource Management Plan. Diamond, J. M. 1975. The island dilemma: lessons of modern biogeographic studies for the design of natural reserves. Biological Conservation 7: 129-146. Donahue, J. P. 1975. A report on the 24 species of California butterflies being considered for placement on the Federal Lists of Endangered or Threatened Species. Submitted to California Department of Food and Agriculture. 58 pp. Duever, L. C. and R. F. Noss. 1990. A computerized method of priority ranking for natural areas. New York State Museum Bulletin 471: 22-33. Emmel, T. C. and J. F. Emmel. 1973. "The Butterflies of Southern California." Natural History Museum of Los Angeles County, Science Series 26:1-148. ERCE. 1991. "Detailed Biological Assessment for the City of Poway." Prepared for City of Poway Planning Department. Everett, W. T. 1979. Sensitive, Threatened and Declining Bird Species of San Diego County. San Diego Audubon Society Sketches 29:2-3. Faeth, S. H. and T. C. Kane. 1978. Urban biogeography: city parks as islands for Diptera and Coleoptera. Oecologia 32: 127-138. Fahrig, L. and G. Merriam. 1985. Habitat patch connectivity and population survival. Ecology 66: 1762-1768. Forman, R. T. T. and M. Godron. 1981. Patches and structural components for a landscape ecology. Bioscience 31: 738-740. Franklin, I. R. 1980. Evolutionary changes in small populations. Pages 135-149 in M. E. Soule and B. A. Wilcox (eds). Conservation Biology: An Evolutionary Perspective. Sinauer, Sunderland, Massachusetts. Game, M. 1980. Best shape for nature reserves. Nature 287: 630-632. Gelbach, F. R. 1975. Investigation, evaluation, and priority ranking of natural reserves. Biological Conservation 8: 79-88. Goldsmith, F. B. 1975. The evaluation of ecological resources in the countryside for conservation purposes. Biological Conservation 8: 89-%. Grinnell, J. and A. Miller. 1944. The distribution of the birds of California. Pacific Coast Avifauna 27: 1-608. 77 Hix, A. B. (ed.) 1990. Sensitivity of San Diego's biological resources: an informational report. Compiled by City of San Diego Planning Department, Development and Environmental Planning Division (primarily Lisa Wood). 29 pp. + attachments. Holland, R. F. 1986. Preliminary Descriptions of the Terrestrial Natural Communities of California. Nongame-Heritage Program, California Department of Fish and Game. 150 pp. Jensen, D. B. 1987. Concepts of preserve design: what we have learned. Pages 595-603 in T. S. Elias, (ed). Conservation and Management of Rare and Endangered Plants. California Native Plant Society, Sacramento, California. Kelly, P. and J. Rotenberry. (In preparation). Buffer zones for ecological reserves in California. In J. E. Keely (ed) The Interface Between Ecology and Land Development in California. Paper presented at the Southern California Academy of Sciences Annual Meeting, Occidental College, May 1-2, 1992. Lacy, R. C. 1987. Loss of genetic diversity from managed populations: interacting effects of drift, mutation, immigration, selection, and population subdivision. Consen'ation Biology 1:143-158. Lande, R. and G. F. Barrowclough. 1987. Effective population size, genetic variation, and their use for population management. Pages 87-123 in M. E. Soule (ed). Viable Populations for Conservation. Cambridge University Press, Cambridge. Laurence, W. F. and E. Yensen. 1991. Predicting the impacts of edge effects in fragmented habitats. Biological Conservation 55: 77-92. Lichtwardt, E. and E. Gold. 1980. Field checklist of Amphibians and Reptiles of San Diego and Imperial counties. Special Publ. No. 3, San Diego Herpetological Society. MacNeill, C. D. 1962. Preliminary report on the Hesperiidae of Baja California. Proceedings of the California Academy of Sciences 30: 91-116. Margules, C. and M. B. Usher. 1981. Criteria used in assessing wildlife conservation potential: a review. Biological Conservation 21: 79-109. Massey, B. W. 1977. A census of the breeding population of Belding's Savannah Sparrow in California, 1977. Study VI, Job 1.2, Final Report. California Department of Fish and Game. McCaskie, G. 1977. A Field Checklist of the Birds of San Diego County. Prepared for San Diego County Parks and Recreation Department. McGurty, B. M. 1980. Survey and status of endangered and threatened species of reptiles natively occurring in San Diego, California. San Diego Herpetological Society. Munz, P. 1974. A Flora of Southern California. University of California Press, Berkeley, California. 1086 pp. Murphy, D. D. 1988. Challenges to biological diversity in urban areas. Pages 71-76 in E. O. Wilson (ed). Biodiversity. National Academy Press, Washington, D.C. 78 Murphy, D. D. 19990. A report on the California butterflies as candidates for endangered status by the United States Fish and Wildlife Service. Draft report for California Department of Fish and Game Contract No. C-1755. 60 pp. Noss, R. F. 1983. A regional landscape approach to maintain diversity. BioScience 33: 700-706. Noss, R. F. 1987. Corridors in real landscapes: a reply to Simberloff and Cox. Conservation Biology 1: 159-164. Oberbauer, T.A. 1991a. Southern California Botanists. Unique soils and plants of limited distribution in the Peninsular Ranges. Paper presented at Symposium of So. California Botanists. October 26, 1991, CSU Fullerton. Oberbauer, T. A. 1991b. In P. Abbott and B. Elliot (eds). Geol. Soc. North Amer., So. Calif. Reg. Sympos. San Diego, October 21-24, 1991. Pryde, P. R. 1984. San Diego: An Introduction to the Region. Kendall/Hunt Publ. Co., Dubuque, Iowa. 297 pp. Rea, A. M., and K. L. Weaver. 1990. Ten taxonomy, distribution, and status of coastal California cactus wrens. Western Birds 21: 81-126. Reed, P. B. 1988. National List of Plant Species That Occur in Wetlands: California (Region 0). Biological Report 88(26.10). United States Fish and Wildlife Service, Department of the Interior. Remsen, J. V. 1978. Bird Species of Special Concern in California. State of California Department of Fish and Game. San Diego Association of Governments. 1988. Draft Comprehensive Species Management Plan for the least Bell's vireo. Prepared by RECON. 195 pp. + appendices. Sauvajot, R. (In preparation). Effects of urban encroachment on wildlife in the Santa Monica Mountains. In J. E. Keely (ed) The Interface Between Ecology and Land Development in California. Based on paper presented at the Annual Meeting of the Southern California Academy of Sciences, Occidental College, May 1-2, 1992. Schonewald-Cox, C. M. and J. W. Bayless, 1986. The boundary model: a geographical analysis of design and conservation of natural reserves. Biological Conservation 38: 305-322. Scott, T. A. 1990. Conserving California's rarest white oak: the Engelmann oak. Fremontia 18:26- 29. Scott, T. A. (In preparation). Effect of housing developments on urban bird populations. In J. E. Keely (ed) The Interface Between Ecology and Land Development in California. Based on paper presented at the Annual Meeting of the Southern California Academy of Sciences, Occidental College, May 1-2, 1992. Shaffer, M. L. 1981. Minimum population sizes for species conservation. BioScience 31: 131-134. 79 Smith, J. P., Jr., and K. Berg. 1988. California Native Plant Society's Inventory of Rare and Endangered Vascular Plants of California. Special Publication No. 1 (4th Edition), California Native Plant Society, Sacramento, California. 168 pp. Soule, M. E. 1991. Land use planning and wildlife maintenance: guidelines for conserving wildlife in an urban landscape. Journal of the American Planning Association 57: 313-323. Soule, M. K, D. T. Bolger, A. C. Alberts, J. Wright, M. Sorice, and S. Hill. 1988. Reconstructed dynamics of rapid extinctions of chaparral-requiring birds in urban habitat islands. Conservation Biology 2: 75-92. Soule, M. E. and M. E. Gilpin. 1991. The theory of wildlife corridor capability. Pages 3-8 in D. A. Saunders and R. J. Hobbs (eds). The Role of Corridors in Nature Conservation. Surrey Beatty, Sydney, Australia. Soule, M. E. and D. Simberloff. 1986. What do genetics and ecology tell us about the design of nature reserves? Biological Conservation 35: 19-40. Stebbins, R. C. 1985. A Field Guide to Western Reptiles and Amphibians. Houghton Mifflin Co., Boston, Mass. Tans, W. 1974. Priority ranking of biotic natural areas. Michigan Botanist 13: 31-39. Tubbs, C. R. and J. W. Blackwood. 1971. Ecological evaluation for planning purposes. Biological Conservation 3: 169-172. United States Fish and Wildlife Service. 1988. Least Bell's Vvreo Draft Recovery Plan. Portland, Oregon. Unitt, P. A. 1984. Birds of San Diego County. Memoir 13, San Diego Society of Natural History. 276 pp. Usher, M. B. 1987. Effects of fragmentation in communities and populations: a review with applications to wildlife conservation. Pages 103-121 in D. A Saunders, G. W. Arnold, A A. Burbridge, and A J. M. Hopkins (eds). Nature Conservation: The Role of Remnants of Native Vegetation. Surrey Beatty, Australia. Wells, P. 1990. Review of Arctostaphylos glandulosa complex. Four Seasons. 8:46-70. Wiggins, I. L. 1980. A Flora of Baja California. Stanford University Press. 1025pp. Wilbur, S. R. 1973. The Red-shouldered hawk in the western United States. Western Birds 4: 15-22. Wilbur, S. R. 1974. The status of the Light-footed Clapper Rail. American Birds 28: 868-870. Wilbur, S. R., P. D. Jorgensen, B. W. Massey, and V. A Basham. 1979. The Light-footed Clapper Rail: an update. American Birds 33: 251. Willet, G. 1933. Revised list of birds of southwestern California. Pacific Coast Avifauna 21: 1-204. 80 Wilson, E. O. and E. O. Willis. 1975. Applied biogeography. Pages 522-534 in M. L. Cody and J. M. Diamond (eds). Ecology and Evolution of Communities. Belknap Press, Cambridge, Massachusetts. Wright, D. F. 1977. A site evaluation scheme for use in the assessment of potential nature reserves. Biological Conservation 11: 293-305. Wright, D. F. and S. P. Hubbell. 1983. Stochastic extinction and reserve size: a focal species approach. Oikos 41: 466-476. Yahner, R. H. 1988. Changes in wildlife communities near edges. Conservation Biology 4: 333-339. Zedler, P. H. 1977. Life history attributes of plants and fire cycles; a case study in chaparral dominated by Cupressus forbesii, pp. 451-458, in: Mooney, H. and L. Conrad (tech. coor.), Proceedings of the Symposium on the Environmental Consequences of Fire and Fuel Management on Mediterranean Ecosystems. Palo Alto, California. Zedler, J. B. 1982. The ecology of southern California coastal salt marshes: a community profile. U.S. Fish and Wildlife Service. FWS/OBS-81/54. 110pp. [Second printing with corrections 1984.] 81 FEDERAL AND STATE DESIGNATED SENSITIVE PLANT AND WILDLIFE SPECIES RESIDENT OR BREEDING IN SAN DIEGO COUNTY BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the ClTY OF CARLSBAD HABITAT MANAGEMENT PLAN FEDERAL AND STATE DESIGNATED SENSITIVE WILDLIFE SPECIES OCCURRING IN SAN DIEGO COUNTY SPECIES USFWS CDFG BIRDS Aimophila ruficeps canescens C23 Southern California Rufous-crowned Sparrow Agelaius tricolor Tricolored Blackbird C2 None CSC? Ammodramus (Passerculus) sandwichensis beldingi Belding's Savannah Sparrow Ammodramus (Passerculus) sandwichensis rostratus Large-Billed Savannah Sparrow Amphispiza bellii bellii Bell's Sage Sparrow Campylorhynchus brunneicapillus sandiegensis Coastal Cactus Wren Charadrius alexandrinus nivosus Western Snowy Plover Chilodanius niger Black Tern C2 C2 C2 C2 Cld C2 CSC None None CSC None Empidonax traillii extimus Southwestern Willow Flycatcher Eremophila alpestris actia California Horned Lark Falco peregrinus anatum American Peregine Falcon Haliaeetus leucocephalus Bald Eagle Lanius ludovicianus Loggerhead Shrike Laterallus jamaicensis Black Rail Cl C2 FEf FE C2 C2 None None SE SE None None Oreortyx pictus Moutan Quail Pelecanus occidentalis califomicus California Brown Pelican Plegadis chihi White-faced Ibis Polioptila californica californica California Gnatcatcher Rallus longirostris levipes Light-footed Clapper Rail Sterna antillarum browni California Least Tern Sterna elegans Elegant Tern Strix occidentalis occidentalis California Spotted Owl Vireo bellii pusillus Least Bell's Vireo C2 FE C2 Proposed Endangered FE FE C2 C2 FE None SE CSC CSC SE SE CSC None SE MAMMALS Choeronycteris mexicana Mexican Long-tongued Bat Dipodomys stephensi Stephens' Kangaroo Rat Euderma maculatum Spotted Bat Eumops perotis califomicus California Mastiff Bat Lepus califomicus bennettii San Diego Black-tailed Jackrabbit Macrotus califomicus California Leaf-nosed Bat Neotoma lepida intermedia San Diego Desert Woodrat C2 FE C2 C2 C2 C2 C2 None STf None CSC None CSC None Onychomys torridus ramona C2 Southern Grasshopper Mouse Ovis canadensis cremnobates C2 Pennisular Bighorn Sheep Perognathus (Chaetodipus) califomicus femoralis C2 Dulzura California Pocket Mouse Perognathus (Chaetodipus) fallax fallax C2 Northwestern San Diego Pocket Mouse None ST None None Perognathus (Chaetodipus) fallax pallidus Pallid San Diego Pocket Mouse Perognathus longimembris brevinasus Los Angeles Pocket Mouse Perognathus longimembris intemationalis Jucumba Little Pocket Mouse Perognathus longimembris pacificus Pacific Pocket Mouse C2 C2 C2 C2 None CSC None CSC REPTILES Ambystoma califomiense California Tiger Salamander Cnemidophorus hyperythrus Orange-throated Whiptail Cnemidophorus tigris multiscutatus Coastal Western Whiptail Clemmys mamarota pallida Southwestern Pond Turtle Coleonyx swaitafd Barefoot Banded Gecko Coleonyx variegatus abbotti San Diego Banded Gecko Crotalus ruber ruber Northern Red Diamond Rattlesnake C2 C2 C2 Cl C2 C2 C2 None CSC None CSC ST None None Diadophus punctatus similis San Diego Ringneck Snake Eumeces skiltonianus interparietalis Coronado Skink Lampropeltis zonata pulchra San Diego Mountain Kingsnake Licharana trivirigata rosafusca Coastal Rosy Boa Phrynosoma coronatum blainvillei San Diego Horned Lizard Phrynosoma mcalli Flat-tailed Horned Lizard Salvadora hexalepis virgultea Western Patch-nosed Snake Sauromalus obesus Common Chuckwalla Sceloporus graciosus vandenburgianus Southern Sagebrush Lizard Thamnophis hammondi Two-striped Garter Snake C2 C2 C2 C2 C2 Cl C2 C2 C2 C2 None None None None CSC CSC None None None None AMPHIBIANS Bufo (microscaphus califomicus) califomicus Arroyo Toad Ensatina eschscholtzi klauberi Large-blotched Salamander Rana aurora draytoni California Red-legged Frog Rana muscosa C2 C2 Cl C2 CSC CSC CSC CSC Mountain Yellow-legged Frog INVERTEBRATES INSECTA Coelus globosus Globose Dune Beetle Euphydryas editha quino Quino Checker Euphyes viestris harbonsi Harbison's Dun Skipper Lycaena hermes Herme Copper Mitoura thornei Thome's Hairstreak Panoquina errans Salt Marsh Skipper Pseudocopaeodes eunus Wandering Skipper Pyragus ruralis lagunae Laguna Mountains Skipper C2 C2 C2 C2 C2 C2 C2 C2 None None None None None None None None ANOSTRACA Branchinecta "sandiegonensis San Diego Fairy Shrimp Streptocephalus woottoni Riverside Fairy Shrimp Petitioned for Listing as Endangered Proposed None Endangered C2 - Category 2 Candidate* CSC — California Species of Special Concern SE -- State Endangered Cl — Category 1 Candidate' FE — Federally Endangered ST — State Threatened Species currently imdescribed, but under consideration for species status. Category 2 Candidate for federal listing includes those taxa for which existing biological information may warrant listing, but for which substantial biological information to support a proposed listing is lacking. Category 1 Candidate for federal listing includes those taxa for which there exists sufficient biological information to support a proposal to list as threatened or endangered. STATE AND FEDERALLY RECOGNIZED SENSITIVE PLANT SPECIES OCCURRING IN SAN DIEGO COUNTY SPECIES USFWS CDFG CNPS* Acanthomintha Uicifolia San Diego Thorn-mint Ambrosia pumila San Diego Ambrosia Aphanisma blitoides Aphanisma Arctostaphylos otayensis Otay Manzanita Astragalus deanei Dean's Milk Vetch Astragalus douglasii var. perstrictus Jacumba Milk Vetch Astragalus magdalenae var. peirsonii Peirson's Milk Vetch Astragalus oocarpus Descanso Milk Vetch Astragalus tener var. titi Coastal Dunes Milk Vetch Baccharis vanessae Encinitas Baccharis Brodiaea filifolia Thread-leaved Brodiaea Brodiaea orcuttii Orcutt's Brodiaea Calamagrostis densa Dense Reed Grass Calamintha (Satureia) chandleri Cl C2 C2 C2 C2 C2 C2 C2 C2 C2 C2 C2 C2 C2 SE None None None None None SE None SE SE SE None None None List IB, 3-3-2 List IB, 3-2-2 List 3, ?-?-2 List IB, 3-2-3 List IB, 3-2-3 List IB, 1-2-2 List IB, 2-2-2 List IB, 3-1-3 List IB, 3-3-3 List IB, 2-3-3 List IB, 3-3-3 List IB, 1-3-2 List 4, 1-1-2 List 4, 1-1-2 San Miguel Savory Calochortus dunnu Cl Dunn's Mariposa Lily Caulanthus simulans Cl Payson's Caulanthus Caulanthus stenocarpus Cl Slender-pod Caulanthus Ceanothus cyaneus Cl Lakeside Ceanothus (wild-lilac) Chaenactis parishii C2 Parish's Chaenactis Chorizanthe orcuttiana Cl Orcutt's Spineflower Chorizanthe parryi var. femandina Cl San Fernando Valley Spineflower Cordylanthus maritimus ssp. maritimus FE Salt Marsh Bird's-beak Corethrogyne filaginifolia var. linifolia Cl Del Mar Mesa Sand Aster Cryptantha ganderi Cl Gander's Cryptantha Delphinium hesperium ssp. cuyamacae Cl Cuyamaca Larkspur Downingia concolorvar. brevior Cl Cuyamaca Lake Downingia Dudleya brevifolia Cl Short-leaved Dudleya Dudleya multicaulis Cl Many-stemmed Dudleya Dudleya variegata Cl Variegated Dudleya Dudleya viscida Cl Sticky Dudleya Eryngium aristulatum var. parishii Cl San Diego Button-celery Rare List IB, 2-2-2 None List 4, 1-2-3 Rare List IB, 3-2-2 None List IB, 3-2-2 None List 4, 1-1-2 SE List 1A None List 1A SE List IB, 2-2-2 None List IB, 3-2-3 None List IB, 3-3-3 Rare List Ib, 2-2-3 SE List IB, 3-3-3 SE List IB, 3-3-3 None List IB, 1-2-3 None List 4, 1-2-2 None List IB, 3-2-3 SE List IB, 1-3-2 Ferocactus acanthodes C2 California Barrel Cactus Ferocactus viridescens C2 San Diego Barrel Cactus Fremontodendron mexicanum C2 Mexican Flannelbush Galium angustifolium ssp. borregoense C2 Borrego Bedstraw Githopsis diffusa ssp. filicaulis C2 Mission Canyon Bluecup Hazardia orcuttii C2 Orcutt's Hazardia Hemizonia conjugens C2 Otay Tarplant Hemizonia floribunda C2 Tecate Tarplant Heuchera brevistaminea C2 Laguna Mtns. Alumroot Lepechinia cardiophylla C2 Heart-leaved Pitcher Sage Lepechinia ganderi C2 Gander's Pitcher-sage Lepidium flavwn var. felipense C2 Borrego Peppergrass Lessingia glandulifera var. tomentosa C2 Warner Springs Lessingia Lilium parryi var. parryi C2 Lemon Lily Limnanthes gracilis var. parishii C2 Parish's Meadowfoam Linanthus orcuttii C2 Orcutt's Linanthus Lupinus excubitus var. medius C2 Mountain Springs Bush Lupine None List 4, 7-3-2 None List 2, 1-3-1 Rare List IB, 3-2-2 Rare List IB, 3-2-3 None List IB, 3-3-2 None List IB, 3-3-2 SE List IB, 3-3-2 None List IB, 2-2-2 None List IB, 3-1-3 None List IB, 3-1-2 None List IB, 3-1-2 None List IB, 3-1-3 None List IB, 3-1-3 None List 4, 1-2-2 SE List IB, 2-2-3 None List IB, 3-1-2 None List IB, 2-1-3 Machaeranthera asteroides var. lagunensis C2 Laguna Mtns. Aster Mahonia nevinii Cl Nevin's Barberry Mimulus aridus C2 Low Bush Monkey Rower Monardella hypoleuca var. lanata C2 Felt-leaved Monardella Monardella linoides spp. viminea Willowy Monardella Monardella nana ssp. leptosiphon San Felipe Monardella Mullla clevelandii San Diego Goldenstar Myosurus minimus var. apus Little Mousetail Navarretia fossalis San Diego (Ditch) Navarettia Nolina interrata C2 C2 C2 C2 C2 Cl Dehesa Nolina Opuntia parryi var. serpentina C2 Snake Cholla Opuntia wigginsii C2 Wiggins' Cholla Orcuttia calif omica Cl California Orcutt Grass Orobanche parishu ssp. brachyloba C2 Short-lobed Broomrape Orthocarpus lasiorhynchus C2 San Bernardino Mtns. Owls-clover Perideridia gairdneri ssp. gairdneri C2 Gairdner's Yampah torreyana ssp. torreyana Torrey Pine C2 Rare SE None None SE None None None None SE None None SE None None None None List IB, 3-3-3 List IB, 3-3-3 List 4, 1-1-2 List IB, 3-1-2 List IB, 2-3-2 List IB, 3-2-3 List IB, 2-2-2 List 3, 2-3-2 List IB, 2-3-2 List IB, 3-3-2 List IB, 3-3-2 List IB, 3-1-2 List IB, 2-3-2 List IB, 2-2-2 List IB, 1-2-3 List IB, 1-2-3 List IB, 3-2-3 Poa atropurpurea Cl San Bernardino Blue Grass Pogogyne abramsii FE San Diego Mesa Mint Pogogyne nudiuscula Cl Otay Mesa Mint Ribes canthariforme C2 Moreno Currant Rorippa gambellii C2 Gambel's Water Cress Rubus glaucifolius var. ganderi C2 Cuyamaca Raspberry Salvia eremostachya C2 Desert Sage Senecio ganderi C2 Gander's Butterweed Solanum tenuilobatum C2 Narrow-leaved Nightshade Tetracoccus dioicus C2 Parry's Tetracoccus Xylorhua orcuttii C2 Orcutt's Woody Aster None List IB, 2-2-3 SE List IB, 2-3-3 SE List IB, 3-3-2 None List IB, 3-1-3 None List IB, 3-3-2 None List IB, 3-1-3 None List 4, 1-1-1 Rare List IB, 3-2-3 None List IB, 3-1-3 None List IB, 3-2-2 None List IB, 2-1-2 California Native Plant Society 1988 List of Species Designations IB: Species is rare or endangered in California and elsewhere. 3: Plants about which more information is needed. 2: Rare or endangered in California, more common elsewhere. 4: Plants of limited distribution (a watch list). Note: Plants on CNPS list IB meet CDFG criteria for Rare of Endangered Listing. R-E-D Code R - (Rarity) 1 - Rare, but found in sufficient numbers and distributed widely enough that the potential for extinction or extirpation is low at this time. 2 - Occurrence confined to several populations or one extended population. 3 - Occurrence limited to one or a few highly restricted populations, or present in such small numbers that it is seldom reported. E - (Endangerment) 1 - Not endangered 2 - Endangered in a portion of its range 3 - Endangered throughout its range D - (Distribution) 1 - More or less widespread outside California 2 - Rare outside California 3 - Endemic to California D D 0 ENVIRONMENTAL IMPACT REPORTS AND OTHER DOCUMENTS CONSULTED BIOLOGICAL RESOURCES AND HABITAT ANALYSIS in support of the CITY OF CARLSBAD HABITAT MANAGEMENT PLAN Agua Hedionda EIR (329) Alanda Project EIR (83-5) Alanda Project EIR (83-5, Part II) Anderson EIR (81-10) Airport Business Center EIR (81-6) Arroyo La Costa Master Plan EIR (86-2) Batiquitos Lagoon EIR (84-3) Batiquitos Pointe EIR (82-4) Bressi Ranch EIR (83-10) Buena Vista Park Plaza EIR (82-5) Calavera EIR (403) Camino Hills EIR (83-9) Carlsbad Highlands EIR (80-8) Carlsbad Highlands EIR (80-8, Supplemental EIR) Carlsbad Land Investors EIR (83-8) Carlsbad Oaks (81-4) City Operations Center EIR (82-1) Coast Waste Management EIR (84-1) Cannon Road: Reach 1 EIR (87-1) Del Mar Financial EIR (83-1, General Information) Evans Point EIR (85-3) Hosp Grove EIR (86-4) HPI Development EIR (83-2) Hunt Properties EIR (83-2, DEIR General Plan) Hunt Properties EIR (83-2, Annexation of City of Carlsbad) Huntington Palomar Project EIR (81-9) Kelly Ranch EIR (83-4) La Costa Northeast EIR (149) La Costa Vale EIR (35) Lake Calavera EIR (89-3) Macario Canyon Park EIR (80-9) Occidental Land Inc. EIR (81-1) Poinsettia Lane EIR (82-6) Pointe San Malo Condominium EIR (80-4) Rancho Carillo EIR (80-7) Rancho Del Cerro EIR (85-2) Rancho La Costa EIR (114) Ranch Santa Fe Road EIR (91-1) Robert's Group Project EIR (83-7) Robertson Ranch EIR (81-7) Royal Palms EIR (85-5) Santa Fe Glens EIR (276) Santa Fe Knolls Preliminary Environmental Information (85-5) Seabluff EIR (81-8) Seawall EIR (84-2) Sherman/Southers EIR (81-5) Stagecoach Park EIR (84-5) Telescope Point EIR (81-2) Windsong Shores Focus EIR (83-3) Wooley Annexation EIR (82-3) EXHIBIT 2 Revised and Updated Work Program for Completion of the Habitat Management Plan (HMP) PHASE III Taskl Preserve Design and Gap Analysis A. Based on analysis completed in Phase II, identify most valuable preserve areas. B. Identify habitat areas currently protected 1. Constrained lands. 2. Open Space under existing General Plan or zoning. 3. Existing project-related open space. 4. Other already protected areas. C. Identify habitat areas with potential to be protected by proposed Open Space and Conservation Resource Management Plan. D. Identify high priority habitat areas not already protected. E. Identify appropriate buffers, corridors, and regional connections. F. Identify habitat areas where development should be allowed if compensation made for habitat loss. G. Identify areas where development can occur without impacts to habitat. H. Identify Final Recommended Preserve and Corridor System Boundaries. Task 2 Coordination with Other Agencies and Programs, including: A. U.S. Fish and Wildlife Service. B. State of California Department of Fish and Game and Natural Communities Conservation Program. C. North County Wildlife Forum. D. City of San Diego Multi-Species Conservation Plan. Task 3 Coordination with Carlsbad Development Policy Documents A. Coordinate with Open Space and Conservation Resource Management Plan. B. Coordinate with update of Land Use Element of General Plan. C. Integration of HMP into General Plan. Task 4 Establish Legal Framework for Implementation of HMP A. Determine legal parameters and mechanisms for acquisition of land, such as "friendly condemnation", open space easement, etc. B. Draft ordinances to provide for transfer of development rights, establishment of new zoning categories, and other land use tools. C. Evaluate institutional options for preserve ownership and management. Tasks Mechanisms for Acquisition/Protection of High Priority Habitat Areas Not Already Protected A. Acquisition and Funding Strategy 1. Identify appropriate funding mechanisms, including local, state, and federal sources. 2. Evaluate feasibility of candidate funding mechanisms. B. Funding for Maintenance and Management 1. Estimate management and maintenance costs. 2. Evaluate sources of funding for management and maintenance, including endowment and maintenance assessment district. C. Other Mechanisms for Acquisition/Protection 1. Transfer of Development Rights. 2. Use of General Plan/zoning for protection. Task6 Management and Maintenance A. Evaluate need for revegetation/restoration in Preserve and Corridor System. B. Identify allowable and prohibited uses within Preserve and Corridor System. C. Identify points of public access into System, and explore methods for controlling access. D. Identify and evaluate alternatives for enforcement. E. Identify compatible and incompatible uses adjacent to System, and explore methods for minimizing indirect impacts of adjacent uses. F. Develop public education program. G. Identify need for interpretive signing and potential for interpretive center. H. Develop process for determining final institutional arrangements. Task 7 City Council Status Report and Recommendation to Proceed. PHASE IV Task 8 Prepare final Preserve and Corridor System Implementation and Management Report Task 9 Pursue Citywide Habitat Conservation Plan (HCP) A. Prepare Draft HCP document. B. Environmental Documentation 1. Conduct environmental scoping to determine extent of environmental review. 2. Issue Notice of Preparation and proceed with preparation of appropriate documents in compliance with California Environmental Qualtiy Act (CEQA) and National Environmental Policy Act. C. Consider addressing necessary General Plan amendments and related actions in CEQA review. D. Finalize HCP document and environmental documents for adoption by City, U. S. Fish and Wildlife Service, and California Department of Fish and Game. Task 10 Presentation of final documents to City Council for adoption. ALL RECEIVED Hofman Planning Associates September 1, 1992 City Councilmembers City of Carlsbad 1200 Carlsbad Village Drive Carlsbad, CA 92008 SUBJECT: Carlsbad HMP - Biological Resources and Habitat Analysis Dear Councilmembers: Thank you for the opportunity to provide input on the Biological Resources and Habitat Analysis for the Carlsbad Habitat Management Program (HMP). We recognize that this report marks a significant milestone in the HMP work program and represents the diligent efforts of all parties involved in the HMP. The purpose of this letter is to support the staffs recommendations regarding the HMP and to move forward with Phase III of the work program as soon as possible. However, we have a few concerns which we wish to document at this time but which we are confident can be addressed during Phase III. HPA has reviewed the Biological Resources and Habitat Analysis and has spoken with staff regarding the intent of the Preserve Planning Areas. It is our understanding that the Preserve Planning Areas (PPAs) represent land within Carlsbad from which a preserve could ultimately be constructed. Only a portion of the entire PPA area would be set aside if a preserve is implemented, not the entire PPA. In addition, it is our understanding that while some land may already be publicly held, any privately held land would either be: (1) included because there are already mechanisms which will allow for it to be set aside (such as the 15 % growth management Open Space requirement); or (2) acquired through some mutually agreeable form of compensation. We feel it is important to recognize that the amount of land ultimately preserved will be dependent on the availability of financing to acquire the property for the preserve. We look forward to working with staff to assess the financial feasibility of the preserve during Phase III of the work program. We would also like to express concern regarding the buffer widths proposed in Section 5.3. While the Biological Resources and Habitat Analysis does state that the recommended widths should be only guidelines, we feel it is important to allow for consideration of biological sensitivity of habitat and to maintain maximum flexibility in determining buffer widths during environmental review of affected projects. On behalf of several property owners, HPA has worked with staff to refine information in the document to reflect the most accurate information available, however, there remain a few areas HMP Comments, P. 2 September 1. 1992 of property owner concern. The Carrillo Ranch property owners feel that the location of Wildlife Corridor WC2-5B would better serve the needs of wildlife if it were shifted to the west of Melrose Drive north of Palomar Airport Road to take advantage of existing steep slopes covered with native vegetation. Once it crosses Palomar Airport Road, it should be realigned to take advantage of a large steep north-south trending canyon on the easterly edge of the Bressi Ranch property. In its present location the corridor crosses future Melrose Avenue and would severely impact the developability of the site with questionable wildlife benefits. Also, the Sunny Creek area property owners in Zone 15 have concerns regarding the inclusion of land in the Preserve Planning Areas which has been farmed for several generations and does not currently support native vegetation. Staff is aware of these concerns and has agreed to work with the property owners during the completion of Phase III to resolve these and any other concerns which may arise. These concerns will be documented to the HMP Advisory Group. This is acceptable to the property owners, who do not wish to delay the progress of the program. In summary, we believe this program represents a unique opportunity, if it is implemented with flexibility, to provide for wildlife preservation while allowing for the continued economic development of the City. Carlsbad's proactive approach to this difficult situation is setting an example for other jurisdictions to follow. Thank you for the opportunity to participate in the Habitat Management Program. Lisa King of our staff will be in attendance at the City Council meeting to answer any questions you may have. Sincerely, Bill Hofman BH:LK cc: Ray Patchett Marty Orenyak Michael Holzmiller Don Rideout City Clerk