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HomeMy WebLinkAbout; Chevron/Koll Parcels Bioligical Constraints Report; Chevron/Koll Parcels Bioligical Constraints Report; 1993-08-16BIOLOGICAL CONSTRAINTS REPORT CHEVRON/KOLL PARCELS Prepared for: CITY OF CARLSBAD 2075 Las Palmas Carlsbad, California • Prepared by: P&D ENVIRONMENTAL SERVICES A Division of P&D TECHNOLOGIES 401 West "A" Street, Suite 2500 San Diego, California 92101 (619)232-4466 August 16, 1993 Table of Contents TABLE OF CQNTENTS Page SECTION 1 INTRODUCTION i 1.1 Geographical Limits of the Study Area i 1.2 Topography and Land Use '. T 1.3 Survey Methodology 1 SECTION 2 EXISTING CONDITIONS ..... 3 2.1 Vegetation . ; 4 2.1.1 Riparian Woodland 4 2.1.2 Freshwater 4 2.1.3 Upland Habitats . . . : 4 2.1.4 Disturbed/Ruderal 5 2.2 Wildlife .................[[.. 5 2.2.1 General Wildlife Uses in the Project Vicinity 5 2.2.2 Habitat Value for Wildlife 6 2.2.3 Wildlife (Corridors : 6 2.3 Sensitive Biological Resources 7 2.3.1 Habitats ................ 7 2.3.2 Plant Species .. 7 2.3.3 Wildlife Species . . 10 2.4 Regulatory .... . . ^4 SECTION 3 POTENTIAL CONSTRAINTS I5 3.1 Introduction ; . . . 15 3.2 Significant Biological Issues 16 3.3 Locally Important Biological Issues ...................... 17 3.4 Not Significant Biological Issues is SECTION 4 POTENTIAL MITIGATION AND RECOMMENDATIONS 18 4.1 Introduction 1g 4.2 Mitigation for Significant Biological Issues 19 4.2.1 Wetlands and Riparian Habitats 19 4.2.2 Endangered and Threatened Species . 19 4.3 Recommendations for Locally Important Biological Issues 20 SECTION 5 REFERENCES 21 Chevron/KoU Biological Constraints Report P&D Environmental Sarvices Table of Contents LIST OF FIGURES Page Figure 1 Project Vicinity 2 Figure 2 Biological Resources (Map Pocket) LIST OF TABLES Table 1 Plant Species of Concern in the Chevron/Koll Project Region . 8 Table 2 Wildlife Species of Concern in the Chevron/Koll Project Region 11 Chevrort/Koll Biological Constraints Report P&D Environmental Services Introduction 1.0 INTRODUCTION The following Biological Constraints Report summarizes the existing biological resources, and the constraints these resources may pose to future development, of the Chevron/Koll properties within the City of Carlsbad. 1.1 GEOGRAPHICAL LIMITS OF THE STUDY AREA The Chevron/Koll properties site is located in central-coastal San Diego County, within the city of Cartsbad. The approximately 250 acre site is bordered on the west by Hidden Valley Road and on the south by Palomar Airport Road. To the north lies Macario Canyon and industrial uses to the east. 1.2 TOPOGRAPHY AND LAND USE Topography onsite ranges from approximately 100 to 300 feet above sea level. The northern portion of the sites consists of steep cliffs and native habitat. The southern portion of the site below College Road consists of disturbed native habitats and construction pads. The northeastern boundary consists of a densely wooded drainage. The majority of the site is currently undeveloped with relatively few buildings and paved roads. The only paved roads onsite are College Road and industrial access roads directly off of College Road. The buildings include industrial buildings along the eastern boundary. The remaining undeveloped areas consist of disturbed areas and natural habitat. Existing surrounding land uses in the area include Agua Hedionda Lagoon to the north-west, Palomar Airport to the southeast, agricultural uses to the north, and industrial to the east and the south. 1.3 SURVEY METHODOLOGY The project site was surveyed on foot and vehicle by P&D Technologies biologists. All habitats were visited, and all observed plants were recorded. Wildlife species onsite were identified directly by sight or by vocalizations, or indirectly by their scat, tracks, or burrows. Where particularty dense vegetation or steep topographic relief was encountered, observations were made using binoculars. Field notes were maintained throughout the surveys. Surveys for onsite plant and wildlife resources were conducted on the July 29, 1993 between 0700 and 1600 hours and on August 2, 1993 betweenQ715 and 1100 hours. No focused surveys for sensitive plant or wildlife species were conducted, although the presence or absence onsite of suitable habitat for sensitive species that occur in the site's vicinity was identified. Chevron/Koll Biological Constraints Report P&D Environmental Services Page 1 PROJECT SITE % W No Scale Figure 1 Vicinity Map Introduction The primary focus of the survey was to document and map in the size, location, and general quality of all habitat types and the presence or potential presence of any sensitive resources' (plant or wildlife) observed onsite. Mapping of the Chevron/Koll project site was conducted on aerial photographs at 1 inch = 100 foot scale. No detailed plant transects or animal trapping studies were conducted as part of this effort. Nomenclature used throughout this report conforms to Hickman (1993), Munz (1974) or Beauchamp (1986) for plants, Holland (1986) for plant communities and habitat types, Amencan Ornithological Union (AOU/1983) for birds, Jennings (1983) for reptiles and amphibians, and Jones (1982) for mammals. 2.0 EXISTING CONDITIONS The project site currently supports six different habitat types: ripanan habitats, freshwater marsh, chaparral, Diegan sage scrub, and disturbed areas.. Each of these habitats are discussed below including plant species composition, sensitive resources present, and wildlife value. The distribution of plant communities onsite is depicted in Figure 2 (map pocket). Approximate habitat acreages are as follows: VEGETATION TYPE ACRES Willow Woodland 3.0 Disturbed Willow Woodland 0.4 Mulefat Scrub 1.4 Coastal Sage Scrub 16.8 Disturbed Coastal Sage Scrub 5.9 Southern Mixed Chaparral 13.78 ^ Chamise Chaparral 3.3 Disturbed Mixed Chaparral 9.24 Disturbed/Ruderal 188.7 Chevron/Koll Biological Constraints Report P&D Environmental Services Page 3 Existing Conditions 2.1 VEGETATION 2.1.1 Riparian Woodland Two types of riparian habitat occur in the Chevron/Koll property areas, mulefat scrub and willow woodland. The willow woodland occurs along the northeastern property boundary and scattered within drainages throughout the project site. This habitat is characterized by hydrophytic plants such as arroyo willow (Salix lasiolepis), black willow (Salix goodingii) and mulefat (Baccharis salicifolia). The willow trees along the northeastern boundary form almost a continuous canopy formirig a forest like setting. The understory of the npanan woodland is not well developed. Patchy occurrences of rush (Scirpus), cattail (Typha), willow herb (Epilobium sp) and Mexican tea (Chenopodium sp.) occur throughout the understory of the woodland. The other disjunct drainages containing willow woodland have a lack of understory due to adjacent agricultural and construction disturbance. The lack of an understory of this riparian woodland lowers its habitat quality for wildlife. The mulefat scrub habitats occur in drainages throughout the site. The mulefat scrub onsite is dominated by (Baccharis salicifolia), and evergreen woody shrub. The understory within this community is very disturbed and contains non-native plant specie. 2.1.2 Freshwater Marsh The freshwater marsh occurs in patches within the dense willow woodland along the northeastern property boundary. This habitat occurs where the willow trees are lacking and the ground is too moist to support riparian woodland or upland plant species. The dominant plants include narrow-leaved cattail (Typha angustifolia), and curty dock (Rumex crispus). 2.1.3 Upland Habitats Upland habitat is defined here as undisturbed habitat not associated with the wetlands. Upland habitat in general is grouped here into two groups: chaparral and Diegan sage scrub. Chaparral habitat onsite occurs in two different forms. These include chamise chaparral and southern mixed chaparral. Scattered throughout the southern portion of the site are large patches of chamise chaparral. Chamise chaparral is dominated by chamise (Adenostoma fasciculatum) usually to the exclusion of all other species. The southern mixed chaparral onsite occurs in large patches throughout the site. The largest communities of southern rtiixed chaparral occurs in the northern portion of the site. This chaparral type is dominated by large shrubs including lemonade berry (Rhus integrifolia), laurel sumac (Malosma laurina), toyon (Heteromeles arbutifolia) and Mexican elderberry (Sambucus mexicana). The understory consists of a variety of Diegan sage scrub species including California sagebrush (Artemisia californica), black sage (Salvia mellifera) and California buckwheat (Eriogonum fasciculatum). P&D Environmental Services Chevron/Koll Biological Constraints Report Page 4 " Existing Conditions Diegan sage scrub is found in small patches intermixed with southern mixed chaparral or scattered throughout the site. The coastal sage scrub community is dominated by California sagebrush, black sage, California buckwheat and lemonade berry. The Diegan sage scrub habitat adjacent to the drainages onsite has many of the same components but the California sagebrush is replaced in dominance with coyote bush (Baccharispilularis) and coastal isocoma (Haplopappus venetus). 2.^.4• Disturbed/Ruderal Disturbed/ruderal areas occur throughout the site. These areas include non-native grasslands and habitat adjacent to roads, industrial parks and construction areas. The non-native grasslands include areas that have been previously cleared or grazed, allowing non-native grasses and ruderal (weedy) species to invade. Ruderal species occur in sizable populations where compacted or loose soils, high temperatures, intense light, and low moisture confer a competitive advantage over native plant species. Non-native grasses include wild oat (Avena sp.), ripgut grass (Bromus diandrus), and foxtail chess (Bromus rubens). Common ruderal species include black mustard (Brassica nigra), Russian thistle (Salsola tragus), crystalline iceplant (Mesembryanthemum crystallinum), and white sweet clover (Melilotus alba). 2.2 WILDLIFE 2.2.1 General Wildlife Use in the Project Vicinity No amphibian species were observed onsite; however several would be expected based on the.habitat, including the Pacific treefrog (Hyla regilla), Pacific slender salamander (Batracsops pacificus), and the California Xoa6 (Bufo boreas). A number of these species are known to frequent a variety of habitats from sea level to high into the mountains. These species commonly breed in marshes, lakes, ponds, roadside ditches, reservoirs, and slow streams in woods, meadows, and grassland. Two reptile species have been observed onsite; western rattlesnake (Crotalus viridis). and western fence lizard (Sceloporus occidentalis). Other reptile species common to north coastal San Diego County which are expected to occur onsite within the coastal sage scrub and chaparral habitats include the side-blotched lizard (Uta stanburiana), stuped racer (Masticophis laterlis), common kingsnake (Lampropeltis getulus), and gopher snake (Pituophis melanoleucus). Several species of birds were observed utilizing the Chevron/Koll project site. Most of these species were observed within or adjacent to the riparian woodland or are typical residents within sage scrub, chaparral, or disturbed communities. Commonly occurnng species of the upland habitats include California towhee (Pipilo fuscus), bushtits (Psaltriparus minimus), ar^d northern mockingbird (/W/mus polyglottos). California gnatcatchers were observed in three locations within the site, although no focused surveys per USFWS protocol were conducted for this species. Chevron/Koll Biological Constraints Report . p&D Environmental Services Page 5 Existing Conditions Several mammal species were observed utilizing the project site. These include Audubon's cottontail (Sylvilagus audubonii), California ground squirrel (Spermophilus beecheyi), and coyote {Cam's latrans). In areas that support native habitats such as the Diegan sage scrub, chaparral and riparian communities wildlife is generally abundant and diverse. However, wildlife utilizing the project site overall consists of a limited representation of what normally woijld be expected to occur in the coastal foothills and valley regions of northern San Diego County. This is due to the histonc agncultural activities and recent construction grading adjacent to the site. The presence of continuous agncultural activities and farmworkers onsite and in the general project vicinity, as well as the surrounding urbanization, may preclude the ability for portions of the site to support a wider variety of wildlife species. 2.2.2 Habitat Value for Wildlife Wildlife usage of the site is contained pnmarily within the riparian habitat and the chaparral habitat. The large expanse of agricultural fields north of the project provide little use to wildlife in general. In fact, the lack of cover for small mammals and reptiles reduces the use of this area by larger predator species. Most wildlife species of Southern California are habitat specific. That is, riparian bird species are generally dependent upon wetland plant species for forage and nesting, and birds located in upland habitats are able to survive in drier climates and require specific xeric plant species for nesting. Mammal species are more diverse in their habitat uses but generally will reside within one specific habitat. The northeastern boundary of the project site supports a variety of wetland habitats which provide excellent cover and nesting potential for numerous wildlife species. Riparian habitats generally support a greater diversity of wildlife species than other habitats in the Southern California region. This is due primarily to a greater plant diversity. 2.2.3 Wildlife Corridors An important aspect of vvildlife use of a site is the ability for animals to move through an area to access water or new territbnes for nesting. Except for mammals, the wildlife of the Chevron/Koll site are pnmarily habitat restrictive and therefore utilize their appropnate habitat. Ripanan bird species utilize the Macario Creek corridor for access to habitat both upstream and downstream. Mammals require access to water and usually need vegetative cover while traveling. Macano Creek serves as an important wildlife corridor onsite. This creek has an extensive habitat and drainage basin upstream and ultimately drains to Agua Hedionda Lagoon. Wildlife from inland habitats, and particularty riparian species, utilize drainage corridors for access to foraging areas, nesting territories and protective cover from predators. P&D Environmental Services ' Chevron/Koll Biological Constraints Report Page 6 . , Existing Conditions 2.3 SENSITIVE BIOLOGICAL RESOURCES Sensitive or special interest plant and wildlife species and habitats are those which are considered rare, threatened, or endangered within the state or region by local, state, or federal resource conservation agencies. Sensitive habitats, as identified by these same groups are those which generally support plant or wildlife species considered sensitive by these resource protection agencies or .groups. Sensitive species and habitats are so called because of their limited distnbution, restricted habitat requirements, or particular susceptibility to human disturbance, or a combination of these factors. Sources used for the determination of sensitive biological i^esources include: U.S. Fish and Wildlife Service (USFWS, 1991), California Department of Fish and Game (CDFG, 1987), California Natural Diversity Database (1992), and California Native Plant Society (Smith and Berg, 1988). Tables 1 and 2 list the sensitive plant and wildlife species occurring on the project site or known from the project vicinity, their respective legal status, and the habitat in which these species are typically found. 2.3.1 Habitats Sensitive habitats observed onsite include wetlands (riparian habitats, freshwater marsh), and Diegan coastal sage scrub. Wefland habitats, in general, are considered sensitive biological resources because they have been dramatically reduced in California, including San Diego County. These habitats provide high levels of food and nutrients, not to mention a valuable water source, in the and climate of Southern California. This habitat's sensitivity and its ultimate reduction is evidenced by the large number of declining birds species closely associated with or dependent on this habitat type for reproduction. Wetland habitats,, including freshwater marsh and riparian habitats, are considered a particularty sensitive resource by the California Department of Fish and Game, U.S. Fish and Wildlife Service and the Environmental Protection Agency. Wetland habitat protection is specifically addressed by the Galifornia Department of Fish and Game Code, sections 1600-1606 (Streambed Alteration Agreement) and the U.S. Army Corps of Engineers, Section 404 permit process (Clean Water Act). Wetland habitat is considered a valuable, but declining resource, locally as well as nationally. - Diegan coastal sage scrub is considered a sensitive-habitat by the USFWS and the CDFGr It is estimated that as much as 80 percent of the original acreage of this habitat in the State has been lost as a result of urban expansion in coastal areas. Additional evidence of the decline of this once common habitat is the growing number of declining plant and animal species associated with it. 2.3.2 Plant Species The sensitive plant species known to occur within the vicinity of the Chevron/Koll project site are descnbed on table 1. No directed surveys were completed for these species, thus the table only identifies suitable habitat present within the project site. Many of the species are Chevron/Koll Biological Constraints Report p&D Environmental Services , • , Page 7 Existing Conditions Table 1 PLANT SPECIES OF CONCERN IN THE CHEVRON/KOLL PROJECT REGION Species Status Typical Habitat Notes Adolphia californica California spinebush CNPS 2 Chap Potential habitat Acanthomintha ilicifolia San Diego Thornmint CD, FC2 CNPS IB Chap, Css Possible habitat onsite, if clay soils are present Ambrosia pumila San Diego ragweed FC2 CNPS IB Css VGrs Potential habitat Arctostaphylos glandulosa var. crassifolia Del Mar manzanita LC Chap Potential habitat Artemisia palmeri San Diego Sagewort CNPS 2 Css Potential habitat Baccharis vanessae Encinitas baccharis CE, FC2 CNPS IB Chap Potential habitat Ceanothus varrucosus Wart-stemmed ceanothus CNPS 2 Chap Potential habitat Cerocarpus minutiflorus San Diego rnountain mahogany LC Chap Potential habitat Chorizanthe orcuttiana Orcutt's spineflower CE, FC2 CNPS IA Css; ; Potential habitat Comarostaphylis diversifolia Summer holly CNPS IB Chap Potential habitat Corethrogyne filaginfolia var. linifolia Del Mar sancJ aster, Del Mar mesa sand aster FC2 CNPS IB Chap Potential habitat Dichondra occidentalis Western pony foot, western dichondra FC3c CNPS 4 Chap, Css . Potential habitat Harpoganella palmeri Palmer's grappling hook CNPS 2 Chap, Css Potential habitat Brodiaea filifolia Thread-leaved Brodeae CE FC2 VGRL Possible habitat, if clay soils are present P&D Environmental, Services Page 8 Chevron/Koll Biological Constraints Report Existing Conditions Species Status Typical Habitat Notes Brodiaea orcuttei Orcutt's Brodiae FC2 VGRL Possible habitat, if clay soils are present Juncus acutus ssp. sphaerocarpus Spiny Rush CNPS 4 Alkaline Marsh Potential habitat Iva hayesiana San Diego marsh-elder, southern poverty weed CNPS 2 Alkaline Marsh Potential habitat Ophioglossum tusitanicum ssp. califomicum Adder's tongue ferm CNPS 4 FC3c VGrs, VP Possible habitat, if clay soils are present Selaginella cinerascens * Ashy club moss. Mesa club moss, mesa mossfern CNPS 4 Chap, Css Potential habitat Status FCI FC2 FCS CE CNPS IB CNPS 2 CNPS 3 CNPS 4 LC Canciidate for federal listing, sufficient Infornnation for listing. Candidate for federal listing, insufficient information for listing at this time. No longer considered for federal listing; plant considered too widespread or common. Listed as endangered in California. Plants considered rare and endangered by the California Native Plant Society Plants rare in California but common elsew/here. > ssj-s Plants which require more information Watch list. Local Concern. ' , Habitat Chap Chaparral Css Coastal sage scrub Mdws Meadows VGrs Valley grasslands VP Vernal Pools Ow Oak Woodland Chevron/Koll Biological Constraints Report P&D Environmental Services Page 9 Existing Conditions associated with maritime chaparral. Although there are no pure stands of maritime chaparral onsite suitable conditions (i.e., soil type, topography and moisture regime) are present for many of these species. 2.3.3 Wildlife Species Several wildlife species considered sensitive by state, federal, or local resource conservation agencies or jurisdictions have been detected in areas adjacent to the project site during previous field surveys (i.e., P&D 1992). One of these species was observed during this recent surveys California gnatcatcher, but others may reasonably be expected to utilize appropriate habitat on the project site. These species include the San Diego (coast) horned \\zard(Phrynosoma coronatum blainvelli), the orange-throated whiptail lizard (Cnemidophorus hyperythrus beldingi) and southwestern pond turtle (Clemmys marmorata pallida). Table 2 lists the sensitive wildlife species observed onsite during recent surveys or thought to occur in the area of the project site. Sensitive wildlife species actually observed or expected to occur onsite are denoted in Table 2 with an asterisk (*) and discussed below. Endangered/threatened species known or expected to occur onsite are discussed below. Least Bell's vireo (Vireo bellii pusillus) . The least Bell's vireo is a state and federally endangered species. Loss and degradation of breeding habitat on a regional level, in addition to nest parasitism by the brown-headed cowbird (Molothrus ater), have resulted in a severe decline in the least Bell's vireo population in California. Throughout this species range, habitat conversion for agricultural purposes have removed much of the original riparian woodlands required for, nesting by this vireo. Flood control measures and channelization have further depleted the riparian habitats used by the vireo and other birds. Cattle grazing has also impacted habitat by removing the understory vegetation necessary for nesting birds. The significant reduction in the population size and range of the vireo resulted in its listing as federally endangered in May 1986. The least Bell's vireo prefers mature riparian habitat with a dense understory of young willows (Salix spp.), mulefat, California rose (Rosa californica), and a variety of other shrubby species. The vireo is, generally found in areas that include trees such as willow, sycamore (Platanus racemosa). or cottonwood (Populus spp.), particularly where the canopy is within or immediately adjacent to an understory layer of vegetation (Salata 1983). A recent analysis indicates that this species prefers stratified vegetation, with small amounts of aquatic and herbaceous cover (RECON 1990). Another significant ecological variable is the width ofthe willow riparian vvoodland. The vireo shows a strong preference for wide woodlands, which typically exhibit more stratification of vegetation. A marked increase in occupied habitat occurs as the vyidth of the willow riparian woodland exceeds 50 meters wide versus 10 meters or less (RECON 1990). Potential habitat onsite occurs in the northern willow woodland. , ' p&D Environmental Services Chevron/Koll Biological Constraints Report Page 10 Table 2 WILDLIFE SPECIES OF CONCERN IN THE CHEVRON/KOLL PROJECT REGION Species Status and Authority Status in San Diego County Status on the Site San Diego Horned Lizard (Phrynosoma coronatum blainvillei) USFWS-C2 CDFG-2-Protected reptile Depleted due to pet collection ahd habitat destruction. Potential habitat onsite. Orangethroat Whiptail (Cnemidophorus hyperythrus) USFWS-C2 CDFG-2-Protected reptile Principal threat is loss of habitat. Locally abundant where it still occurs. Potential habitat onsite. Brown Pelican (Pelecanus occidentalis) State and Federally Endangered Common non-breeder along the coast. May forage adjacent to site at Agua Hedonionda Lagoon. Peregrine Falcon (Falco peregrinus) State and Federally Endangered . Rare fall and winter visitor. May forage occasionally in the vicinity. California Black Rail (Laterallus jamaicensis) State Rare Extirpated, formerly uncommon resident. Not expected due to inappropriate habitat. Clapper Rail (Rallus longirostris) State and Federally Endangered Uncommon resident very localized. Not expected due to inappropriate habitat. Snowy Plover (Charadrius alexandrinus) Federal Category 2 Common migrant localized breeder. May forage on or near site. Possible breeder offsite. California Least Tern (Sterna albifrons browni) State and Federally Endangered Common but localized summer resident. Breeds offsite at Agua Hedionda Lagoon; Belding's Savannah Sparrow (Ammodramus sandwichensis beldingi) State Endangered Common but localized resident. May occur in vicinity at Agua Hedionda Lagoon. Black-shouldered Kite (Elanus caeruleus) CDFG-Fully protected Suffered serious decline early in this century. Potential habitat onsite. Table 2 WILDLIFE SPECIES OF CONCERN IN THE CHEVRON/KOLL PROJECT REGION Species Status and Authority Status in San Diego County Status on the Site Cooper's Hawk (Accipiter cooperi) Locally sensitive CDFG protected Declining as a nesting species throughout the state; sensitive to reduction bf riparian and oak habitats. Potential habitat onsite. ' Sharp-shinned Hawk (Accipiter striatus) Locally sensitive CDFG Protected Relatively common winter resident; does not breed in County. May occur as a seasonal foraging species. Red-shouldered Hawk (Buteo lineatus) Locally sensitive CDFG Protected Thought to be declining but appears to be recovering. Potentail habitat onsite. Common Barn Own (Tyto alba) Locally sensitive CDFG Protected Common resident of woodland areas. Potential habitat onsite. California Gnatcatcher (Polioptila californica) USFWS-Proposed for endangered CDFG-Species of special concern Restricted to coastal sage scrub. Range is discontinuous throughout. Observed onsite. Least Bell's Vireo (Vireo bellii pusillus) USFWS-Endangered CDFG-Endangered Restricted to riparian habitats. Potential habitat onsite. Yellow Warbler (Dendroica petechia) Locally sensitive Common migrant, uncommon breeder. Potential habitat onsite. Yellow-breasted Chat* (Icteria virens) Locally sensitive Breeds throughout County in riparian woodland. Potential habitat onsite. Existing Conditions Two issues possibly affecting the use of this area by the vireo include disturbance by^ transients and cowbirds. Occasional disturbances from transients living in the vicinity of the' habitat occupied by the vireo may be a factor if the bird is unpaired. Brown-headed cowbirds were observed frequently on the study site. The presence of cowbirds may impact the reproductive success for vireos attempting to breed in this area. Focused surveys per USFWS rotocol would be required (April through July) to determine if the least Bell's vireo occurs on . the site. California Gnatcatcher (Polioptila californica) This small, sedentary bird is generally ecologically restricted to the sage scrub plant community of Southern California. This species was listed as threatened by the U.S. Fish and Wildlife Service in March 1993. The California gnatcatcher is a permanent resident of the sage scrub community,-a unique and diverse vegetation type that many experts consider to be one of the most endangered habitats in the continental United States (Atwood, 1990). Subtle differences in plant species composition, vegetative structure, fire history, and geographic location may affect habitat suitability. Approximate estimates of the number of California gnatcatchers presently occurring in the United States range from 1,200 to 2,000 pairs (Atwood, 1990) to 2,562 pairs (USFWS, 1993), with sizable and stable populations persisting in Orange, Riverside, and San Diego counties. No reliable data on the territory size of this bird in San Diego County have been published, although biologists working with the California gnatcatcher in San Diego County in the last few years (Sweetwater Environmental Biologist; 1986; WESTEC, 1987; ERCE, 1990) have indicated territories ranging form 2 to 14.5 acres. Extensive studies of color banded individuals by ERCE (1900) have indicated larger territories by up to 75%. For example, a pair of California gnatcatchers that spends most of its time within approximately 13 acres may, during the course of the breeding season use an area as large as approximately 23 acres. California gnatcatchers were observed in several locations on the site; however, focused surveys per USFWS protocol would be required to determine the extent of occupied habitat and the approximate population size on the site. Raptors expected onsite include Cooper's hawk (Accipiter coope/-/), black-shouldered kite (Elanus caeruleus). red-shouldered hawk (Buteo lineatus). Red-tailed hawk (Buteojamaicensis). American kestrel (Falco sparverius). Northern harrier (Circus cyaneus) and Turkey vulture (Cathartes aura). Birds of prey (raptors) as a group are considered sensitive because of loss of foraging areas, their vulnerability to human disturbance, their low population densities, and their position at the top of the food chain. Raptor species observed flying over the site presumably forage there. Red-tailed hawks and kestrels are fairly common local residents and/or winter visitors. They are most numerous around agricultural fields and grassland, but wandering individuals are often seen over any habitat. Chevron/Koll Biological Constraints Repon p&D Environmental Services Page 13 Existing Conditions 2.4 REGULATORY Pursuant to Section 404 of the Clean Water Act, onsite wetlands would be subject to permit provisions regulating activities within their boundaries. These provisions are enforced by the U.S. Army Corps of Engineers (ACOE), as well as the U.S. Environmental Protection Agency, with technical input from the U.S. Fish and Wildlife Service. Three factors are considered in the designation of wetlands: the presence of hydrophytic vegetation, hydric soils, and site hydrology. According to the latest ACOE methodology, all three wetland indicators must be present to make a jurisdictional ruling (Corps of Engineel-s Welands Delineation Manual, 1987). Areas indicated as wetlands by all three factors during the rainy season may lack the indicators of hydrology and/or vegetation during the dry season, or the vegetation may have been altered or removed through human disturbance. Such areas may still be regarded as wetlands by resource agencies. Wetland areas on the site that may be subject to ACOE jurisdiction include the riparian woodland, freshwater marsh and a number of small unnamed drainages. Whether or not these wetland areas onsite support a great biological diversity dr are man-made (urban runoff), these riparian habitats would be regulated under the "no net loss of wetlands" policy of the California Department of Fish and Game (CDFG). Any impact to the riparian woodland or brackish marsh habitat onsite would require consultation with the CDFG prior to implementing of any development activity, including vegetation removal and/or grading. The CDFG regulates wetlands under Section 1601/1603 of the California Fish and Game Code through their Streambed Alteration Agreement Program. Any alteration of any streamcourse within the State bf California requires a Streambed Alteration Agreement from the CDFG. The Streambed Alteration Agreement application process requires the applicant to submit project plans, a mitigation program and certified CEQA documentation. Due to the presence of the federally threatened California gnatcatcher and potential presence of the least Bell's vireo, certain activities on the project site may fall under regulations of the State and Federal Endangered Species Act (ESA). Any impacts on these species would require formal consultation with the USFWS pursuant to Section 7 of the federal ESA. The USFWS proposed a special rule in conjunction with listing of the California gnatcatcher as a threatened species. The special rule would allow for "take" of occupied habitat if it results from activities conducted in accordance with a regional approved Natural Communities Conservation Plan (NCCP). The County of San Diego is currently preparing a regional NCCP, although its completion and approval is not expected for at least another year. In the interim, project applicants are making use of Section 7 (for projects) involving federal approved or Section 10 (other projects) of the Endangered Species Act. According to Sectiori 7 ofthe ESA, federal agencies (i.e, the ACOE, regarding its regulatory jurisdiction over portions of the site) are required to ensure that any action they authorize is not likely to jeopardize the continued existence of any endangered or threatened species. In fulfilling this requirement, once it is determined that such species may be present in the project area, federal agencies must consult with the USFWS. The Section 7 consultation process includes P&D Environmental Services Chevron/Koll Biological Constraints Repon Page 14 Existing Conditions the preparation of a report (Biological Assessment) that evaluates the potential effects of the proposed project. The USFWS determines, based upon the submitted Biological Assessment, if the action (project) would jeopardize the continued existence of endangered or threatened species. The project site is also withih the jurisdictional boundaries of the California Coastal Commission (Mello II segment of the Local Coastal Program). Planning and development of the Chevron/Koll site should consider the open space, upland, and wetland policies of the local Coastal Commission. 3.0 POTENTIAL CONSTRAINTS 3.1 INTRODUCTION Biological constraints are defined as areas that support biological resources that may pose a constraint to development of a parcel of land. Constraints are based on local, state and federal agencies' goals, policies and regulations. The constraints of a raw parcel of land are discussed as impacts during environmental documentation per the California Environmental Quality Act (CEQA). Both the general constraints of the Chevron\Koll properties and the potential impacts are discussed below. Impacts on biological resources can be categorized as either direct, indirect, or cumulative. Direct impacts are a result of project implementation, and generally include: the loss of vegetation and sensitive habitats and populations; the introduction of non-native species which may outrcompete and displace native vegetation; activity-related mortalities to wildlife; loss of foraging, nesting or burrowing habitat; destruction of breeding habitats; and fragmentation of wildlife corridors. Indirect impacts occur as a result of the increase in human encroachment in the natural environment and include: off-road vehicle use which impacts sensitive plant or animal species; harassment and or collection of wildlife species; intrusion and wildlife mortality by pets in open space areas following residential development; and inadvertent increased wildlife mortalities along roads. Cumulative impacts occur as a result of on-going direct and indirect impacts for unrelated or fragmented projects. Cumulative impacts are assessed on a regional basis and determined the overall effect of numerous activities on a sensitive resource over a larger area. Per CEQA, there are three levels of adverse impacts associated with biological resources: Significant, locally important, and not significant. Each of these levels of impacts are defined below (Nelson 1981). Significant impacts would result if the project would affect regionally important or unique species or habitat that are susceptible to stresses or changes. These resources include federal or state-listed species, or their habitat; biotic communities, vegetation associations, and habitats of plant and animal species that are highly restricted on a regional basis; habitat that serves as a concentrated breeding, feeding, resting, or migrating ground and is limited in Chevron/Koll Biological Constraints Repon P&D Environmental Services Page 15 Potential Constraints availability; biotic resources of scientific interest because they are at the extreme of either their physical or geographical limits or represent an unusual variation in a population or' community; and areas that serve as habitats to regional plant wildlife and game populations and fisheries. Significant impacts may also occur if the activities of the proposed project would affect federal or state candidate species, regionally sensitive species, or species of special concern. The determination of significance is dependent upon the extent of impact with respect to the regional distribution of the resource. For example, impacts on the California gnatcatcher when it was a candidate species may have been considered significant because of its limited distribution. Locally important impacts may occur on resources that support the functioning and integrity of adjacent areas of high significance. These resources include habitats that are key to the maintenance of localized plant and animal populations even if not significant on a regional basis; areas that act to buffer and protect resources of high significance; and corridors of zones that serve to link areas of high significance and facilitate their ecological interactions. Impacts which would not be considered significant include activities which may affect natural resources but would not change or stress the biological resources in the region. These areas include commonly occurring habitats and areas where biological resources have been previously removed or significantly altered. It should be noted, however, that common habitats may take on increased importance .where they function as buffer zones of sensitive habitats or as wildlife corridors. Each of these different levels of impacts poses a different constraint to the development of a project site. Significant impacts pose the greatest constraint to development. These impacts usually require substantial agency coordination, mitigation and costly delays. Resource agencies typically request that these impacts be avoided before proceeding with project submittals. Locally important impacts are generally not constraining, although they may be considered as contributing to a significant cumulative impact. If so, they may require mitigation and local agency review. Impacts that are considered not significant pose no constraint to the development of a project. These levels of impacts and constraints are utilized below in the discussion of specific constraints of the Chevron/Koll project site. 3.2 SIGNIFICANT BIOLOGICAL ISSUES The most significant biological resources on the Chevron/Koll project site are the presence of the California gnatcatcher and the occurrence of wetland habitats, in particular the riparian woodland. . As discussed in Section 2,4, a Section 7 consultation with the USFWS would be required to address potential impacts on the California gnatcatcher, unless the project is delayed until certification of the County's NCCP. Section 2.4 also states that impacts on the riparian P&D Environmental Sen/ices Chevron/Koll Biological Constraints Report Page 16 Potential Constraints woodland of Macario Creek would be considered significant from a biological perspective as well as by the CDFG, USFWS, California Coastal Commission and the City of Carlsbad. The potential use of this site by the least Bell's vireo for breeding may also pose a considerable constraint to development of the Chevron/Koll project site if it is detected as a breeder onsite. Direct impacts on this endangered species or its habitat would require, as for the gnatcatcher, a Section 7 consultation with the USFWS AND CDFG and mitigation. Since the breeding status of this species onsite is currently unclear, further investigations should be conducted. Ill addition to direct impacts, indirect impacts on the Caiifornia gnatcatcher and least Bell's vireo may also be considered significant. Indirect impacts such as noise, light, domestic dog and cat activity and pedestrians may be considered significant. Any impact, either direct or indirect, would require consultation with the resource agencies. The loss of the coastal sage scrub habitat onsite, either occupied or unoccupied by the gnatcatcher, would, be considered significant based on the limited distribution of this habitat compared to its historic occurrence in Southern California, and to the number of sensitive species this habitat may support onsite. Significant impacts would also occur if any other state or federally listed endangered or threatened species, or species proposed for listing, occurs onsite. Directed surveys would be required to determine if such species, other than those discussed above, occur onsite. Note that species other than those listed in Tables 1 and 2 may be listed or proposed for listing prior to site development. Resource agencies should be contacted prior to site development to ensure that Section 9 of the ESA, which prohibits "take" of listed species, is not violated. 3.3 LOCALLY IMPORTANT BIOLOGICAL ISSUES Locally important biological issues for this particular project comprise primarily indirect impacts associated with development ofthe site. These would include increased noise, sedimentation into onsite and adjacent wetlands, litter accumulation, and increased human encroachment. Increased noise and light levels from the conversion of agriculture to commercial or residential may adversely affect wildlife in adjacent native habitats.. Increasing noise, glare and human activities often force wildlife further into the existing native habitat increasing competition for food and nesting resources. For this reason, buffers are often recommended to allow the noise and glare to dissipate prior to affecting the wildlife. Buffers vary depending on the adjacent land use, type of habitat, and wildlife involved. Sedimentation into wetland resources degrades the quality of the habitat and eventually changes the topography and hydrology of a region. Agua Hedionda Lagoon has suffered from sediment deposition, resulting in the creation of a shallow lagoon. Sedimentation and pollution control should be incorporated into the design of the Chevron/Koll project site. The lack of any such controls may result in biological impacts to the habitat and wildlife of onsite wetland resource as well as to habitats downstream. Chevron/Koll Biological Constraints Repon P&D Environmental Services Page 17 Potential Constraints The loss of chaparral and non-native grassland habitats onsite may also constitute locally important impacts, depending upon the extent of impact. 3.4 NOT SIGNIFICANT BIOLOGICAL ISSUES The loss of disturbed ruderal areas would not be considered significant biologically. The loss of these areas is not expected to significant or adversely impact existing ecological conditions of the site. The loss of chaparral and non-native grassland habitats onsite may constitute not significant impacts, depending upon the extent of impact. 4.0 POTENTIAL MITIGATION AND RECOMMENDATIONS 4.1 INTRODUCTION Under CEQA, mitigation is required for all significant biological impacts. In addition, the California Coastal Commission, CDFG and the ACOE 404 permit process generally require mitigation for the loss of wetland resources. The following mitigation measures are recommended to offset significant impacts to below a level of significance. Recommendations are also given to offset locally important biological impacts. Although mitigation measures are not often required for locally important impacts, local jurisdictions often implement these measures to minimize cumulative impacts vyithin the region. No mitigation is required for impacts to disturbed areas or agriculture. The USFWS has adopted mitigation guidelines for significant biological impacts. These include, in order of preference, 1) avoidance of impacts, 2) minimization of the impacts to the maximum extent practicable, and 3) mitigation, only if avoidance is not feasible and the impacts have been minimized. Whenever possible, the significant impact should be avoided using design alternatives such as increasing development density in disturbed habitats while reducing or eliminating density in areas that support sensitive biological resources. If it is not feasible to avoid the impact due to either jurisdictional policy or to economic or topographic constraints, then minimizing of impacts should be considered. Impacts on significant resources should be minimized to the greatest extent feasible. Minimizing includes decreasing lot size, narrowing roadways, increasing buffer zones, etc. If unavoidable impacts to- significant resources, would still occur, a mitigation plan that would meet the requirements of the reviewing or permitting agencies will be required. Sections 4.2 and 4.3, below, are based on the assumption that the planning process for Chevron/Koll will consider avoiding and minimizing significant impacts prior to incorporating the mitigation measures outlined. P&D Environmental Services Chevron/Koll Biological Constraints Repon Page 18 , Potential Mitigation and Recommendations 4.2 MITIGATION FOR SIGNIFICANT BIOLOGICAL ISSUES 4.2.1 Wetlands and Riparian Habitats Mitigation for significant impacts associated with the Macario Creek wetlands would be conducted through the revegetation of disturbed land onsite. Different local agencies have different requirements for replacement ratios which are based upon the type and value of the riparian or wetland habitat. For instance, the CDFG usually requires a 3:1 replacement for riparian woodland, a 2:1 replacement for riparian scrub and a 1:1 replacement for marsh habitat. The approved Local Coastal Program encompassing the Chevron/Koll property requires a 3:1 replacement ratio for disturbance to riparian habitats. If an endangered species is present within the wetland habitat, the ratio of replacement may be higher and require an extensive buffer system. Mitigation for the freshwater marsh and riparian habitats will require revegetation on portions of the Chevron/Koll project site. Revegetation would require consultation with the resource agencies and a revegetation biologist specializing in wetland restoration. A seed palette and container specimen plant list would be required. Types of species found onsite will be required to be replaced. Some areas onsite could enhanced, whereas others may require extensive alteration for the creation of wetlands. Typically, the resource agencies prefer the creation of wetlands from uplands in order to avoid a cumulative net loss scenario. A revegetation and monitoring report would be prepared as part of the environmental documentation of the project and would be implemented following project approval and receipt of permits. The revegetation and monitoring report will detail the exact location of each revegetation area, size, species composition, monitoring requirements and success thresholds. All revegetation areas will be placed in permanent open space and restrict traffic to pedestrians and bicycle trails. 4.2.2 Endangered and Threatened Species Mitigation for the significant impacts on the California gnatcatcher, and potentially significant impacts on the least Bell's vireo, would require extensive consultation with the USFWS. A spring survey for the vireo (April through July) should be conducted, and if nesting vireos are observed, occupied habitat will be delineated and mapped. Surveys during the months of December through March would be required to document areas of occupied habitat for the California gnatcatcher. Surveys for both species must be conducted per current USFWS protocol. If impacts on either species cannot be avoided entirely, then a Section 7 consultation (or Section 10[a] permit if there is no federal nexus for the project) under the Endangered Species Act with the USFWS would be required. The buffer zone defined within the Local Coastal Program encompassing Chevron/Koll includes a 150-foot buffer (50-foot biological buffer, 100-foot planning buffer) for areas supporting endangered or threatened species. The buffer zone should include native vegetation (or revegetated to native vegetation), restrict pedestrian access, and allow no other uses than an open space preserve. Since the vireo is a migratory bird and may utilize a different territory within the same Chevron/Koll Biological Constraints Repon . P&D Environmental Services Page 19 Potential Mitigation and Recommendations drainage the following year, it is recommended that the buffer be placed along the entire drainage on the property. As stated previously, directed surveys should be required for all species listed or proposed for listing to avoid violation of the ESA. Other sensitive species for which impacts may be significant should also be surveyed for their occurrence and distribution onsite. 4-3 RECOMMENDATIONS FOR LOCALLY IMPORTANT BIOLOGICAL ISSUES Potential locally important indirect impacts identified include, noise impacts,, siltation of downstream wetlands, pedestrian access and litter accumulation. Each of these impacts have the potential of becoming significant if precautionary measures are not incorporated into the design of the project. Excessive noise effects wildlife adjacent to the noise source. For instance, a noisy roadway adjacent to a riparian woodland may disrupt the breeding cycle of numerous bird species including the least Bell's vireo. It is recommended by the USFWS that if the noise levels exceed 60 dB within native habitat adjacent to proposed development, a noise wall (or other mitigation) should be constructed. Siltation of San Diego County's lagoons has caused the loss and degradation of wetland habitat and its use by wildlife. Development projects, adjacent to and upstream of wetlands have the potential to increase sedimentation into downstream wetlands. Therefore, desiltation basins should be constructed so as to capture sediment flows prior td entering sensitive wetland areas. Desiltation basins should be designed to remove silt as well as typical urban pollutants such as oils and grease. In addition, if desiltation basins are required adjacent to the upland habitat, then these basins may provide sources of water and protective cover for wildlife as well. P&D Environmental Services Chevron/Koll Biological Constraints Report Page 20 ^ References 5.0 REFERENCES Abrams, L. 1923. Illustrated Flora of the Pacific States. Vols. I, II, and III. Stanford University Press, Stanford, CA. Abrams, L. 1960. Illustrated Flora of the Pacific States. Vol. IV. Stanford University Press, Stanford, CA. California Department of Fish and Game (CDFG). 1980. At the Crossroads: A Report on the Status of California's Endangered and Rare Fish and Wildlife. Sacramento, CA.: State of California Resources Agency. California Department of Fish and Game. 1991. "Designated Endangered, Threatened or Rare Plants." State of California Dept. of Fish and Game, Natural Heritage Division, Endangered Plant Program, Sacramento. California Department of Fish and Game. 1991. "State and Federal Endangered, Rare, and Threatened Animals of California." State of California Resources Agency, Sacramento. California Natural Diversity Data Base (CNDDB). 1992. List of CDFG Sensitive Habitats, Natural Community Element Index, CDFG Natural Heritage Division, Sacramento. Garrett, K; and J. Dunn. 1981. Birds of Southern California:,.--Status and Distribution. Audubon Press. Lbs Angeles. Grinnell, J. 1915. A distributional list of the birds of California. Pac. Coast Avifauna 11. Grinnell, J., and A. H. Miller. 1944. The Distribution of the Birds of California. Cooper Ornithological Club, Pacific Coast Avifauna No. 27. Hickman, J. C. 1993. The Jepson Manual Higher Plants of California. University of California Press, Berkeley. ; Holland, R. F. 1986. Preliminarv Descriptions of the Terrestrial Natural Cohimunities of California. Non-game Heritage Program, State of California Department of Fish and Game, Sacramento. Munz, P.A. 1974. A Flora of Southern California. University of California Press, Berkeley. Ornduff, R. 1974. Introduction to California Plant Life. Univ. Calif. Press,-Berkeley. Chevron/Koll Biological Constraints Report . p&D Environmental Services Page 21 References Smith, J.P. and K. Berg, eds. 1988. Inventory of Rare and Endangered Vascular Plants of California. Calif. Native Plant Society, Sacramento. Stebbins, R. C. 1985. Field Guide to Western Reptiles and Amohihian.s. Houghton Mifflin Co., Boston. U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and Threatened Wildlife and Plants. Federal Register 50 r^FR 17 11 anH i 7 i 9 U.S. Dept. Int. U.S. Fish and Wildlife Service. 1991. Endangered and Threatened Wildlife and Plants; Animal Candidate Review for Listing as Endangered or Threatened Species. U.S. Dept. Int. Federal Register 56(225): 58804-36. U.S. Fish and Wildlife Service. 1993. Endangered and Threatened Wildlife and Plants; Threatened Coastal California Gnatcatcher; Final rule and proposed special rule. 50 CFR, part 17, FederaLReaister 58 (59): 1 6742-16759. Zeiner, D. C, W. F. Laudenslayer Jr., K. E. Mayer, M. White, eds. 1990. California's Wildlife. Vol 3. Mammals. California Department of Fish and Game. Sacramento. P&D Environmental Services Chevron/Koll Biological Constraints Report Page 22