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HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Calavera Hills Master Plan Phase II; 2000-08-21BIOLOGICAL ASSESSMENT FOR THE CALAVERA HILLS MASTER PLAN PHASE H & BRIDGE AND THOROUGHFARE DISTRICT NO. 4 & DETENTION BASIN PROJECT, CITY OF CARLSBAD, CALIFORNIA Prepared for CITY OF CARLSBAD PLANNING DEPARTMENT 2075 LAS PALMAS DRIVE CARLSBAD, CA 92009 Prepared by 1927 Fifth Avenue, Suite 200 San Diego, CA 92101-2358 619/ 308-9333 fax 308-9334 GERALD A. SCHEID SENIOR BIOLOGIST RECON NUMBER 3226B AUGUST 2 L 2000 This document printed on recycled paper TABLE OF CONTENTS Introduction 1 Description of the Proposed Action 1 A. Proposed Action 1 B. Impact Analysis and Proposed Mitigation 4 Study Methods 4 Environmental Setting 7 Species Accounts 8 A. Least Bell's Vireo 8 B. Coastal California Gnatcatcher 12 C. Quino Checkerspot Butterfly 15 D. San Diego Thommint 18 E. Arroyo Southwestern Toad 18 F. Southwestern Willow Rycatcher 19 G. Stephens' Kangaroo Rat 20 H. Thread-leaved Brodiaea 21 Federal Candidate Species 22 Conclusions 23 References Cited 23 FIGURES Project Location 2 Project Vicinity ' 3 Location of Least Bell's Vireo 11 Location of Least Bell's Vireo Mitigation 13 Location of Coastal California Gnatcatcher 16 Location of Thread-Leaved Brodiaea 22 TABLES Summary of Impacts 5 Summary of Mitigation 6 S urvey Information for Least B ell' s Vireo 10 Introduction The objective of this biological assessment is to provide U.S. Fish and Wildlife Service with the necessary information on the anticipated impacts to federally listed species occurring or with the potential for occurrence in the project area so that a biological opinion can be issued by USFWS for the proposed action, the Calavera Hills and Bridge and Thoroughfare District No. 4 project. A biological assessment report is used by the Environmental Protection Agency (EPA) and the U.S. Fish and Wildlife Service (USFWS) to evaluate the potential effects of the proposed action(s) on federally listed species, species proposed for federal listing, and designated and proposed critical habitat to determine if any such species or habitat is likely to be adversely affected by the action {Federal Register Vol. 51, No. 106, Rules and Regulations, Section 402.12, Biological Assessments). The document is also used in determining whether a formal consultation is necessary. The biological assessment is required for federal actions that are "major construction activities" which may involve effects to federal listed species that come under the jurisdiction of Section 7 of the Endangered Species Act. The goal of the Section 7 consultation is the issuance of a biological opinion. The biological opinion determines whether the action is likely to jeopardize the continued existence of a listed species or result in the destruction or adverse modification of critical habitat (a jeopardy opinion) or the action is not likely to jeopardize the continued existence of a listed species or result in adverse modification to critical habitat (a no jeopardy opinion). A jeopardy biological opinion shall include reasonable and prudent alternatives, if any. Description of the Proposed Action A. Proposed Action The site of the proposed action is located in the northeast quadrant of the city of Carlsbad (Figure 1) and consists of three components: Calavera Hills Master Plan Phase n area. Bridge and Thoroughfare District No. 4, and two proposed detention basins (Figure 2). The Calavera Hills Master Plan area is bounded by State Route 78 (SR-78) on the north and on the south by an east-west line approximately one-half of a mile north of the Rancho Carlsbad Mobile Home Park. The Master Plan's western extent is near Carlsbad Village Drive. The second component of the project is the formation by the City of Carlsbad of a Bridge and Thoroughfare District No. 4 for the extensions of College Boulevard and Cannon Road. College Boulevard would be extended from within the Calavera Hills Master Plan at Carlsbad Village Drive to El Camino Real. The Bridge and Thoroughfare District OCEANSIDE PROJECT LOCATION CARLSBAD ENCINITAS\ 0 t 0 MILES 2.2 M:jobs\3225e\graphics\reginal.cdr 4.4 FIGURE 1 Regional Location of the Project Master Plan Phase II Bridge and Thoroughfare District Detention basins 0 Feet 2000 M:\jobs\3225b\biotec.apr\ii;gional 4000 FIGURE 2 Project Vicinity encompasses the reach of College Boulevard that lies within the boundaries of the Calavera Hills Master Plan. Cannon Road would be extended from El Camino Real easterly to the city of Oceanside. Figure 2 shows the limits of the District and the approximate alignments of both roadways. The third component of the project consists of the construction of two detention basins (see Figure 2) by the City of Carlsbad to control flooding impacts within the Calavera Creek watershed. These basins have been recommended near the northeast corner of the Rancho Carlsbad Mobile Home Park. Basin "BJB" at the northwest quadrant of the College Boulevard/Cannon Road intersection would have an inundation area of approximately 15 acres and a storage capacity of 49 acre-feet. Basin "BJ" is located southeast of the College Boulevard/Canon Road intersection and would have an inundation area of approximately 8 acres with a storage volume of 48 acre-feet. The basins are part of a larger drainage plan for the area, and are consistent with the 1994 City of Carlsbad Master Drainage Plan. B. Impact Analysis and Proposed Mitigation A summary of the anticipated impacts from the implementation of the proposed project is given in Table 1. Coastal sage scrub, southern mixed and chamise chaparral, and agricultural land are the vegetation types most affected by the project. Riparian vegetation would also be affected. A summary of the proposed mitigation for impacts to vegetation types considered sensitive is given in Table 2. Mitigation would be accomplished through a combination of on-site preservation of habitat, on-site creation of habitat, off-site purchase of habitat from an approved mitigation bank, or off-site creation of habitat. Study Methods A general biological resources survey was conducted on November 22 and December 13, 1999, and January 5, 12, 17 and 19, 2000, by RECON biologists. Vegetation communities were assessed and mapped for the three project components on a color aerial flown in 1999. The study area for the Bridge and Thoroughfare District component includes a 500- foot corridor surrounding the various alignment alternatives. Animal species observed directly or detected from calls, tracks, scat, nests, or other sign were noted. All plant species observed on-site were documented, and plants that could not be identified in the field were identified later using taxonomic keys. The wildlife surveys include focused surveys for coastal California gnatcatcher, least Bell's vireo, and southwestern willow flycatcher. The California gnatcatcher surveys were conducted by RECON biologists Wendy Loeffler (USFWS permit #PRT-839084) and Cynthia Jones (permit #PRT-811615) according to the USFWS California gnatcatcher TABLE 1 SUMMARY OF IMPACTS FOR THE CALAVERA HILLS MASTER PLAN PHASE U AND THE BRIDGE AND THOROUGHFARE DISTRICT PROJECT Vegetation Type Master Plan Phase II Development Bridge and Thoroughfare District Vegetation Type Permanent Temporary Total Permanent Temporary Total Diegan coastal sage scrab 83.7 1.6 85.3 20.2 2.2 22.4 Southern mixed and chamise 28.2 0.6 28.8 — — — chaparral Non-native grassland 1.9 0.04 1.94 1.6 0.2 1.8 Riparian woodland ~ --2.5* 0.3 2.8 Eucalyptus woodland 0.7 0.1 0.8 1.2 0.2 1.4 Native grassland ~ ~ --~ Riparian scrub -~ ~ 0.6* 0.05 0.65 Riparian forest ---0.06 0.05 0.11 Cismontane alkali marsh ~ --0.6 0.06 0.66 Cismontane alkali marsh 0.06 -0.06 0.2 0.02 0.22 (seasonal) Freshwater marsh ---~ -- Agricultural ---29.1 3.4 32.5 Developed 3.5 0.2 3.7 8.5 0.9 9.4 Disturbed 14.6 0.5 15.1 2.3 0.5 2.8 VEGETATION TOTAL 132.6 3.04 135.7 66.8 7.88 74.74 *1.5 acres of riparian woodland and 0.3 acre of riparian scrub to be impacted is occupied by the least Bell's vireo. TABLE 2 SUMMARY OF PROPOSED MITIGATION FOR THE CALAVERA HILLS MASTER PLAN PHASE II & BRIDGE AND THOROUGHFARE DISTRICT NO. 4 & DETENTION BASIN PROJECT Mitigation Creation of Preservation of Off-Site Habitat Vegetation Type Impact* Ratio Habitat Habitat (on-site) Commitment Total Coastal sage scrub 107.7 2:1 7.7 166.7 50.2 224.6 Riparian woodland 2.8 3:1 8.4 — — 8.4 Riparian scrub 0.65 3:1 2.0 — — 2.0 Riparian forest 0.1 3:1 0.3 — ~ 0.3 Cismontane alkah marsh 0.88 3:1 2.6 ~ — 2.6 *Includes permanent and temporary impacts. survey guidelines (USFWS 1997). Surveys were conducted on November 22 and December 13, 1999, and January 5, 12, 17, and 19, 2000 between the hours of 6:00 A.M. and 12:00 P.M. Survey conditions were optimal for detecting coastal California gnatcatchers, with mild temperatures and winds of 0 to 5 miles per hour. The least Bell's vireo and southwestern willow flycatcher surveys were conducted by RECON biologist Cindy Jones between April 27, 2000 and July 15, 2000. Surveys were conducted according to the USFWS least Bell's vireo survey guidelines (USFWS 1999). All surveys were conducted between 6 A.M. and 8 A.M. on the above dates. Habitat assessments were conducted during the general surveys to determine the potential for the project area to be occupied by other federal listed species that have a lower probability for occurrence. The site was surveyed on foot and notes were made as to the suitability of the native habitats in the project area to support Stephens' kangaroo rat, quino checkerspot butterfly, San Diego thornmint, and thread-leaved brodiaea. Environmental Setting Eleven vegetation communities were identified within the survey area: Diegan coastal sage scrub, southern mixed and chamise chaparral, non-native grassland, riparian woodland, eucalyptus woodland, native grassland, riparian scrub, riparian forest, cismontane alkali marsh, cismontane alkali marsh (seasonal), and freshwater marsh. The rest of the site is comprised of agriculture, developed, or disturbed areas. The plant communities are discussed in greater detail within the biological technical report (RECON 2000). A total of 116 plant species were identified on the site. Of this total, 70 (60 percent) are species native to southern California and 46 (40 percent) are introduced species. Overall, the project area and vicinity provide high value habitat for wildlife species. Much of the site contains moderate to high quality coastal sage scrub and chaparral, which provide suitable habitat for a variety of native wildlife species. Pacific treefrogs {Hyla regilla) were heard within the wetland areas throughout the property during the recent surveys. A number of reptile species were identified during previous surveys on the site, including San Diego gopher snake (Pituophis catenifer annectens \_=P. melanolueccus]), San Diego horned lizard {Phrynosoma coronatum blainyillii), western fence lizard (Sceloporus occidentalis), side-blotched lizard {Uta stansburiana), and Belding's orangethroat whiptail (Cnemidophorus hyperythrus beldingi) (RECON 1991). The diversity of bird species varies with respect to the character, quality, and diversity of vegetation communities. Due to the variety of habitats present on the property, the bird diversity is fairly high. Birds commonly observed on-site include within Diegan coastal sage scrub, Bewick's wren (Thyromanes bewickii), bushtit (Psaltriparus minimus minimus), yellow-rumped warbler (Dendroica coronata), wrentit (Chamaea fasciata), Anna's hummingbird (Calypte anna), California towhee {Pipilo crissalis), spotted towhee {P. maculatus), and California quail (Callipepla californica); within riparian habitats, lesser goldfinch (Carduelis tristis salicamans) and Nuttall's woodpecker (Dendrocopos nuttallii); within native and non-native grasslands, mourning dove (Zenaida macroura marginella), kingbird {Tyrannus sp.), house finch (Carpodacus mexicanus frontalis), and western meadowlark (Sturnella neglecta). Raptors include red-tailed hawk (Buteo jamaicensis), northern harrier (Circus cyaneus hudsonius), turkey vulture {Cathartes. aura), white-tailed kite (Elanus leucurus), American kestrel (Falco sparverius), and Cooper's hawk (Accipiter cooperii). Mammal species observed directly or by sign include cottontail rabbit (Sylvilagus audubonii), southern pocket gopher (Thomomys umbrinus), woodrat (Neotoma sp.), and coyote (Canis latrans). San Diego black-tailed jackrabbit (Lepus californicus) was also observed during previous surveys (RECON 1991). Species Accounts The following sections provide information on the federally proposed and listed species that occur or potentially occur within the project area. Each account contains a brief description of the basic ecology and current distribution of the species, as well as an assessment of potential effects the proposed action may have on each species. A. Least Bell's Vireo Least Bell's vireo (Vireo bellii pusillus) is a state and federally listed endangered species. Least Bell's vireo is one of four subspecies of Bell's vireo. One of the other subspecies, Arizona vireo (V.b. arizonae), occurs in California, but is restricted to the Colorado River. The other subspecies occur in the eastern United States (Franzreb 1989). USFWS has published designated critical habitat areas for the least Bell's vireo (50 CFR 17, February 2, 1994) which results in additional protection requirements under section 7 of the Endangered Species Act of 1973, as amended. The proposed project site does not fall within designated critical habitat. 1. Ecology and Distribution Least Bell's vireo is a small, migratory songbird in the Vireonidae family. Least Bell's vireo winters in Baja California, Mexico, arriving in California from mid-March to April, and departing for Baja California in early September (Garrett and Dunn 1981; Franzreb 1989). This bird is nondescript, being generally gray with white wingbars. Least Bell's vireo has a distinctive song, and is most easily located through its vocalizations. These birds are restricted to dense riparian habitats with canopies of willows (Salix spp.) and an understory comprised of mule fat (Baccharis salicifolia), wild rose (Rosa californica), and other riparian species (Franzreb 1989). Vireos select riparian areas with dense shrub cover and a well-developed understory (RECON 1986). Least Bell's vireo was historically common, ranging from near Red Bluff in Tehama County south through the Central Valley and the foothills of the Sierra Nevadas, and in the coast ranging from Santa Clara County south to San Fernando in Baja California. Historic desert sites included Owens Valley, Death Valley, and oases in the Mojave desert. The population dropped due to loss and degradation of habitat, and this species has been extirpated from many historic areas, including the Central Valley (Franzreb 1989). Currently, least Bell's vireo is known from southern California, with large populations located on the Santa Margarita River in San Diego County and the Prado Basin in western Riverside County (USFWS 1994). The least Bell's vireo population's decline can be attributed to several factors. Loss of riparian habitat is a significant cause in the decline of this species. It has been estimated that 95 to 97 percent of the riparian habitat within the floodplain of southern California has been lost to flood control measures and development (Faber et al. 1989). Degradation of riparian habitat by invasion of exotic plants, grazing practices, and other causes have decreased the amount of available habitat for least Bell's vireo. Cowbird parasitism has also contributed to the decline of least Bell's vireo. 2. Population Information The population of least Bell's vireo for 1981 to 1985 was estimated at 292 territorial males. In 1987, the population estimate was 440 (Franzreb 1989). The population of least Bell's vireo has increased exponentially in recent years. In the Prado Basin, the number of territories increased from 19 to 217 between 1986 and 1995 (Pike et al. 1995). The majority of least Bell's vireos are located in San Diego County, with an estimated 294 territories present in 1986 and an estimated 1,400 territories present in 1998. 3. Recent Surveys of Project Area Surveys conducted according to the USFWS survey protocol for least Bell's vireo were conducted on the site during the 2000 breeding season. Surveys dates, times, weather conditions, and observations are given in Table 3. Least Bell's vireo were observed using habitat along Calavera Creek in two locations (Figure 3). The first location is located upstream of the proposed detention basin "BJB." Here a male bird was observed only once, early during the survey period. It is assumed that this bird moved to a different area. The second location is located near where Calavera Creek enters the Rancho Carlsbad Mobile Home Park. Here a male vireo was observed several times and successfully nested. A juvenile bird was observed in early July at this location. Therefore, the male bird was considered to be paired. TABLE 3 LEAST BELL'S SURVEY INFORMATION Survey Number Date/ Time Temp. (° F.)/ Wind (mph) Sky Conditions Notes* 1 4/27/00 8:00-11:00 A.M. 63-71 0-2/0-4 Cloudy/mostly cloudy No listed species observed 2 5/11/00 6:00-8:00 A.M. 62-65 0/0-2 Cloudy/partly cloudy No listed species observed 3 5/22/00 6:15-9:45 A.M. 64-68 0-2 Cloudy LBV #1, LBV #2, and WIFL all detected in riparian woodland 4 6/4/00 7:00-8:30 A.M. 63-67 0-2 Cloudy-fog/ Sunny No listed species observed 5 6/13/00 6:00-8:45 A.M. 64-72 0-2 Cloudy/mostly cloudy LBV #2 male singing, flying through territory, feeding young. One young visually identified. 6 6/23/00 6:15-8:15 A.M. 68-67 0-2 Cloudy LBV #2 male singing 7 7/5/00 6:45-8:15 A.M. 68-72 0-2 Cloudy/mostly cloudy LBV #2 male singing, flying through territory with mate and one young who was practicing his song 8 7/14/00 6:30-9:00 A.M. 66-69 0-2 Cloudy No listed species observed *LBV# = least Bell's vireo individual; WIFL# = southwestern willow flycatcher individual. • Male vireo • Vireo pair Master plan development area J College Boulevard extension Cannon Road extension 0 Feet 1300 M:\jolis\3226h\gisUiio.a|irtfig3 - final 08/21/00 2600 HGURE 3 Locations of Least Bell's Vireo 4. Impacts Direct permanent impacts to 1.8 acres of riparian woodland on Calavera Creek would occur from the construction of the proposed College Boulevard/Cannon Road intersection. Provided that these habitat impacts occur outside of the vireo breeding season, no direct impacts to the least Bell's vireo are anticipated. There are potential indirect impacts to the least Bell's vireo from noise after the project is compete. These indirect impacts would be primarily from traffic noise. 5. Proposed Mitigation Mitigation for the loss of least Bell's vireo habitat will be achieved by creating willow woodland (i.e., riparian woodland) habitat along Calavera Creek. Approximately 4.8 acres of habitat divided between two locations would be created adjacent to Calavera Creek (Figure 4). Direct impacts to least Bell's vireo individuals shall be avoided by restriction of construction activities near Calavera Creek upstream of the Rancho Carlsbad Mobile Home Park to outside of the breeding season. The breeding season for the least Bell's vireo begins March 15 and ends September 15 each year. Indirect impacts to the remaining habitat on Calavera Creek from noise will be mitigated by features incorporated into the road design that would help reduce noise levels reaching the preserved riparian habitat (e.g., sound walls). 6. Consistency with the City of Carlsbad Habitat Management Plan The proposed project is consistent with the draft City of Carlsbad Habitat Management Plan (City of Carlsbad 1999). Conservation goals outlined in the plan preserve all major populations of least Bell's vireo within the city of Carlsbad identified at the time the HMP document was published. The vireo pair found on Calavera Creek were newly discovered in 2000. The draft Habitat Management Plan states that no direct impacts to least Bell's vireo are expected either because the habitats have been preserved or are covered under the City's no-net-loss of wetlands policy. Indirect impacts are to be minimized through preserve-level or site-specific management measures. The proposed mitigation measures for the project meet these criteria through the creation of habitat to achieve a no-net-loss of wetlands, and through measures to reduce the potential indirect impacts to the species from noise. B. Coastal California Gnatcatcher Coastal California gnatcatcher (Polioptila californica californica) is a federally listed threatened species. On March 25, 1993, the USFWS listed the gnatcatcher as threatened 12 1 L 0 gallon area rs.\\N Detention basin inundation area Master plan development area College Boulevard extension Cannon Road extension t Feet 130 260 FIGURE 4 Location of Mitigation Areas for Least Bell's Vireo M:\|(ihs\.!22rilAds*lii.iss.ripr\nc-l - final DH/DMIII (50 CFR 17, March 30, 1993) pursuant to the federal Endangered Species Act (ESA) of 1973 as amended. On December 10, 1993, pursuant to section 4(d) of the ESA, the USFWS defined specific conditions associated with certain land use activities under which incidental take of gnatcatchers would not be a violation of Section 9 of the ESA (50 CFR 17, December 10, 1993). In July 1997, the USFWS released a set of survey guidelines for assessing potential take of the coastal California gnatcatcher (USFWS 1997). 1. Ecology and Distribution The coastal California gnatcatcher is a small slate-colored bird with a black tail, which it flicks erratically as it perches. The bird has a very distinct mew-like call. During the breeding season, the male develops a black cap that distinguishes it from the female. The gnatcatcher is a non-migratory bird found on the coastal slopes of southern California. It ranges from Ventura County south to Baja California, Mexico (Atwood 1990; Jones and Ramirez 1995). The breeding season of the coastal California gnatcatcher extends from late February through July with the peak of nesting occurring from mid-March through mid-May. There is evidence that this bird has a medium to high susceptibility to nest predation by various animals such as western scrub jays (Aphelocoma californica), snakes and rodents (Atwood 1990), and brown-headed cowbirds (Molothrus ater) (Unitt 1984). The coastal California gnatcatcher is strongly associated with coastal sage scrub habitats below 820 feet in coastal areas and between 820 and 1,640 feet in inland areas (Atwood and Bolsinger 1992); however, not all types of coastal sage scrub communities are used or preferred. This bird appears to be most abundant in areas dominated by California sagebrush (Artemisia californica) (ERC Environmental [ERCE] 1990). Another important plant species in gnatcatcher habitat is California buckwheat (Eriogonum fasciculatum). Coastal sage scrub vegetation occurs on the gentle coastal slopes and mesas of southern California, which are prime locations for agriculture and development. Overall, it is estimated that between 1945 and 1990, 58-61 percent of the coastal sage scrub habitat within the geographic range of the gnatcatcher had been lost (50 CFR 17, March 30, 1993). 2. Population Information Population estimates for the coastal California gnatcatcher vary. Atwood (1992) estimated that 1,811 to 2,291 pairs of gnatcatchers existed in 1992 throughout its range in southern California. The San Diego County population was estimated to consist of 400 pairs in 1980 (Atwood 1980). As interest in the coastal California gnatcatcher has increased in the past few years, more emphasis has been placed on searching for the bird. Consequently, coastal California gnatcatchers have been observed in a number of locations in which it was not previously 14 recorded. Mapping efforts in western San Diego County for the Multiple Species Conservation Program (MSCP) (City of San Diego 1994) and North County Multiple Habitat Conservation Plan (San Diego Association of Governments 1993) have recorded roughly 2,300 pairs of coastal California gnatcatcher excluding Camp Pendleton. The largest populations in San Diego County seem to be in regions from Escondido south to Poway, in Los Peiiasquitos and Carroll Canyons west of Mira Mesa, around Sweetwater Reservoir, and from Lakeside and El Cajon south and east to Crest (Unitt 1984). Other large populations have been found near the Lower Otay Reservoir, on Camp Pendleton, and in the vicinity of Carlsbad and San Marcos. 3. Recent Surveys of Project Area Surveys to document the presence or absence of the coastal California gnatcatcher in the proposed project area were conducted during the spring of 2000 (see Methods section). Three coastal California gnatcatcher territories were observed in the coastal sage scrub habitats on the site and one was observed off-site near El Camino Real (Figure 5). 4. Impacts and Mitigation The proposed project will directly impact approximately 108.8 acres of coastal sage scrub habitat. Portions of this sage scrub habitat are occupied by the coastal California gnatcatcher. Of the-total impact acreage, approximately 83.7 acres of impact would occur from the. master plan area and 25.1 acres from the proposed Cannon Road and College Boulevard extensions. Mitigation for impacts to coastal sage scrub habitat in the project area would be accomplished through a combination of on-site preservation, on-site creation, and off-site opportunities. A total of 166.7 acres of coastal sage scrub habitat within the Master Plan area would be preserved as natural open space. In addition, approximately 7.7 acres of coastal sage scrub habitat would be created on manufactured slopes adjacent to the open space areas in the Master Plan area of the project. Mitigation for coastal sage scrub from the road extensions would total approximately 50.2 acres. This mitigation would occur off-site through either acquisition of unprotected coastal sage scrub habitat, restoration of coastal sage scrub habitat, or payment into an approved mitigation bank. C. Quino Checkerspot Butterfly 1. Ecology and Distribution Quino checkerspot butterfly (Euphydryas editha quino) is a federally listed endangered subspecies. This species is a member of the brush-footed butterfly family (Nymphahdae). The quino checkerspot butterfly is one of 12 subspecies of the editha checkerspot and was formerly known as E. e. wrightii. The quino checkerspot's distribution is defined 15 O Coastal California gnatcatcher 0 1 Master plan development area J College Boulevard extension Cannon Road extension t I 0 Feet 1300 M:\ji)hsU226b\Eis*io.iipi\fig5 - final 08/21100 2600 FIGURE 5 Locations of Coastal California Gnatcatchers primarily by that of its principal larval host plant, dot-seed plantain (Plantago erecta). Although plantain is considered the larvae's primary food source throughout most of its range, it is likely that other native species of plantain (Plantago sp.) and even members of the figwort family (Scrophulariaceae) may be used as well (Brown 1991). Adults use California buckwheat as one nectar source. Quino checkerspot occurs in western Riverside, Orange, and San Diego Counties south into coastal central Baja California, Mexico, near Santo Tomas (Brown, Real, and Faulkner 1992; Emmel and Emmel 1973). Historical localities in San Diego County include Lake Hodges, Rancho Santa Fe, San Miguel Mountain, El Cajon, Dehesa, Dulzura, Dictionary Hill, Chula Vista, Otay Lakes, Kearny Mesa, Proctor Valley, and Brown Field (Brown 1991). The quino checkerspot is restricted to sunny openings on clay soils within shrubland habitats of the coastal and interior foothills of southwestern California and northwestern Baja California, Mexico (50 CRF 17, January 16, 1997). Although quino checkerspot populations tend toward low mobility, it is believed that some individuals of this species may disperse long distances in drier years, and that rare population explosions such as one observed in 1977 may allow dispersing individuals to recolonize areas where the butterfly was eliminated by fire or other disturbances (Ehrlich et al. 1975 as cited in Brown 1991). The loss of small isolated colonies of quino checkerspots may affect the entire subspecies through the loss of the island-like stepping stone populations between larger colonies. The loss of populations, which serve as a source for recolonization, is likely to adversely affect the ability of the quino checkerspot to recover from low population levels (Brown 1991). 2. Population Information Prior to 1997, only seven or eight populations were known within the United States. Five to six populations were near Vail Lake in southwestern Riverside and north-central San Diego Counties, and one was near Upper Otay Lake in San Diego County. However, the Upper Otay Lake population may be extirpated, having last been seen in 1990 (50 CRF 17, January 16, 1997). After the listing of this species, surveys conducted in 1997 located new populations. In the United States quino checkerspots are threatened by loss of habitat as a result of urban development and agricultural, including grazing (50 CRF 17, January 16, 1997). 3. Recent Surveys of the Project Area Focused surveys to detect the presence of quino checkerspot butterfly or its habitat were conducted in 1998 and 1999. No suitable habitat for the quino checkerspot butterfly occurs on-site and therefore, the species is not expected to occur within the project area. 17 4. "No Affect" Evaluation Since habitat for the quino checkerspot butterfly was not observed on the site the project would not affect the continued existence of this species. D. San Diego Thornmint 1. Ecology and Distribution The San Diego thommint (Acanthomintha ilicifolia) is state listed as endangered and is federally proposed as endangered. This species is a small annual from the Lamiaceae (mint) family that is restricted to clay lenses in openings in chaparral or coastal sage scrub communities. San Diego thommint ranges from San Marcos and Alpine to Otay Mesa in San Diego County, to San Telmo in Baja California (50 CRF 17, August 9, 1995). Approximately 40 percent of the 35 known populations have been extirpated. San Diego thommint is currently known from 20 sites in the United States and has been documented at nine sites in Baja California, Mexico (50 CRF 17, August 9, 1995). 2. Recent Survey of the Project Area Suitable habitat for San Diego thornmint was not located within the project site. This species is not expected to occur because the suitable habitat for the species was not observed on the site. 3. "No Effect" Evaluation The proposed action will not affect the continued existence of San Diego thornmint populations. E. Arroyo Southwestern Toad 1. Ecology and Distribution The arroyo southwestern toad (Bufo microscaphus californicus) is federally listed as endangered. This toad ranges coastally from San Luis Obispo County south into northwestern Baja California and is known from six drainages in the desert (Jennings and Hayes 1994). Locally, it has been recorded historically from the Sweetwater, San Luis Rey, and San Diego River drainages (Sloan 1964). As more intensive surveys have been conducted recently, the arroyo southwestern toad is now known from 23 drainages in San Diego County (Brown 1995). However, many of the populations are small and isolated and may not be viable (50 CRF 17, December 16, 1994). 18 The arroyo southwestem toad has very specific habitat requirements. It inhabits sandy banks of washes, streams, and arroyos with low currents and large, deciduous trees. Arroyo south westem toads breed in pools with the majority of the pool greater than one foot deep with a substrate of sand, gravel, or pebbles. The pools tend to lack vegetation (Sweet 1992). Arroyo southwestern toads are nocturnal and breed from March to June depending on local climate. Females lay between 2,000 and 10,000 eggs in strings in the breeding pools. Larvae metamorphose in 65 to 85 days. Adult toads estivate through during the summer in burrows that they dig on sandbars (Jennings and Hayes 1994). Threats to this species include the hydrologic modifications due to dam construction and urbanization, and predation by introduced species including bullfrogs (Rana catesbeiana) and exotic fishes (50 CRF 17, December 16, 1994). 2. Recent Surveys of the Project Area No suitable habitat for this species occurs in the project area. The arroyo southwestern toad is unlikely to occur because the site lacks suitable stream habitat and the level of disturbance caused by agricultural activities is high. 3. "No Effect" Evaluation The project will not impact the arroyo southwestem toad and thus will not affect the continued existence of the species. F. Southwestern Willow Flycatcher 1. Ecology and Distribution The southwestern willow flycatcher (Empidonax traillii extimus) is federally listed as endangered, and all willow flycatchers in California, including the southwestern and two other subspecies (E. t. brewsteri and E.t. adastus), are state listed as endangered. Willow flycatchers are in the Tyrannidae family, and are one of ten species of Empidonax flycatchers in the United States. Empidonax flycatchers are difficult to distinguish apart visually but have distinctive songs. The southwestem willow flycatcher breeds in southern California, Arizona, New Mexico, southern Nevada, southern Utah, western Texas, northwestern Mexico, and possibly southwestern Colorado (50 CRF 17 July 23, 1993). Southwestern willow flycatchers are migrants to San Diego County, arriving on their breeding grounds in mid-May to early June (Garrett and Dunn 1981, Unitt 1984). Other species of willow flycatchers migrate through southem California without breeding here, with the most common migrant being E.t. brewsteri (Unitt 1984). It is virtually impossible to differentiate between subspecies of willow flycatcher during migration. 19 The southwestem willow flycatcher requires riparian habitat with willow (Salix spp.) thickets (Grinnell and Miller 1944). Understory species include Baccharis and Pluchea. Southwestem willow flycatchers also nest in tamarisk (Tamarix spp.) and Russian olive (Eleagnus angustifolia) in areas where these species have replaced the native willows. Surface water is required at nesting sites (Tibbitts et al. 1994, 50 CRF 17 July 23, 1993). Population declines for the southwestern willow flycatcher can be linked to a loss of riparian habitat due to water diversion, flood control, urbanization, grazing, and invasion of non-native species. Parasitism by brown-headed cowbirds is also a factor in the decline of this species (50 CRF Febmary 27, 1995). In Califomia, permanent populations of this subspecies are located on the Santa Inez River in Santa Barbara County, the Kem River in Kem County, Prado Basin in Riverside County, and the Santa Margarita River and San Luis Rey River in San Diego County. An estimated 110 to 143 territories were present at these locations in 1995, with 51 to 63 territories estimated in San Diego County in 1995. 2. Recent Surveys of Project Area Surveys conducted during the spring of 2000 found one southwestern willow flycatcher on the site. A single individual was observed once during the first survey of the site, but it was never relocated on subsequent surveys. This species did not nest in habitat on the site. 3. "No Effect" Evaluation The project will not impact the southwestem willow flycatcher and will not affect the continued existence of the species. G. Stephens' Kangaroo Rat 1. Ecology and Distribution The Stephens' kangaroo rat (Dipodomys stephensi) is a state and federally Usted endangered species. This species of kangaroo rat has five toes on each hind foot and closely resembles the more common Pacific kangaroo rat (Dipodomys agilis). These two species are best distinguished by skull chai'acteristics. Distribution of Stephens' kangaroo rat is limited. This species is found only in the San Jacinto Valley in southern Califomia, in western Riverside County, and southern San Bernardino and northern San Diego Counties. Stephens' kangaroo rat habitat includes dry open spaces within grassland, fallow agricultural fields, and sparse coastal sage scmb communities. Kangaroo rats tend to forage for seeds in open spaces between shrubs (Schoenherr 1992); therefore, sparse. 20 rather than dense, vegetation is preferred. Suitable topography is generally flat to moderately sloping with sandy or gravelly soils. Filaree (Erodium spp.) frequently dominates the best habitat, especially during and shortly after the rainy season (RECON 1989). Due to an increase in land conversions to agriculture and urbanization, habitat loss is the primary cause for this species' population decline. 2. Recent Surveys of Project Area No suitable habitat for this species occurs within the project area. No Stephens' kangaroo rats are expected to be in the project area. 3. "No Effect" Evaluation The proposed project would not affect the Stephens' kangaroo rat. The project site lacks suitable habitat for this species. Therefore, the project would not affect the continued existence of this species. H. Thread-leaved Brodiaea I. Ecology and Distribution Thread-leaved brodiaea (Brodiaea filifolia) is federally proposed as a threatened species. This species is a member of the Liliaceae and is a perennial which grows from a corm. It blooms from May and June. Thread-leaved brodiaea is known from two populations in Glendora, Los Angeles County, approximately five populations in south Orange County, one population in Arrowhead Hot Springs, San Bernardino County, ten populations in western Riverside County, and eighteen populations in San Diego County (State of California 1995). The largest population in San Diego County is located in the San Marcos-Vista-Carlsbad area (50 CRF 17, December 15, 1994). Thread-leaved brodiaea is commonly found in areas near vemal pools or seasonally moist grassland (Reiser 1994). 2. Recent Surveys of Project Area A few scattered patches of thread-leaved brodiaea were found within the Master Plan area of the project in native grassland habitats during surveys conducted in the spring of 2000 (Figure 6). 3. "No Effect" Evaluation The proposed project would not impact the native grassland habitat that contains the thread-leaved brodiaea population on the site. Therefore, the project would not affect the thread-leaved brodiaea nor affect the continued existence of this species. 21 Master plan development area College Boulevard extension Cannon Road extension HGURE 6 0 Feet 1100 2200 Location of Thread-Leaved Brodiaea M:\jobs\3226b\ttis\bici.aprtfi56 - lin.il 08/21/00 Federal Candidate Species None of the species currently named by the USFWS as candidates for listing as endangered or threatened (50 CFR Part 17 "Endangered and Threatened Species, Plant and Animal Taxa; Proposed Rule" Federal Register Feb. 28, 1996) have been observed on the site, and none are considered to be potentially present. Conclusions The proposed project would impact habitat of two federal listed species, least Bell's vireo and coastal California gnatcatcher. Mitigation measures are proposed to off-set these impacts. Therefore, the proposed project would not affect the continued existence of these species. References Cited Atwood, J. L. 1980 The United States Distribution of the California Black-tailed Gnatcatcher. Westem Birds 11:65-78. 1990 Status Review of the Califomia Gnatcatcher (Polioptila californica). Unpublished technical report, Manomet Bird Observatory, Manomet, Massachusetts. 1992 A Maximum Estimate of the California Gnatcatcher's Population Size in the United States. Westem Birds 23(1): 1-9. Atwood, J. L., and J. S. Bolsinger 1992 Elevational Distribution of Califomia Gnatcatchers in the United States. Journal of Field Ornithology. 63: 159-168. Brown, C. 1991 Sensitive and Declining Butterfly Species (Insecta: Lepidoptera) in San Diego County, Califomia. Draft, Dudek and Associates, May. 1995 Drainages with Extant Arroyo Toad Populations. Unpublished data. Brown, J. W., H. G. Real, and D. K. Faulkner 1992 Butterflies of Baja California: Faunal Survey, Natural Histoiy, Conservation Biology. Lepidoptera Research Foundation, Inc. 23 California, State of 1995 Thread-leaved Brodiaea (Brodiaea filifolia) Recovery Workshop Summary. February 22, 1995. Temecula, California. City of Carlsbad 1999 Habitat Management Plan for Natural Communities in the City of Carlsbad. December 1999. Ehrlich, P. R., R. R. White, M. C. Singer, S. W. McKechnie, L. E. Gilbert 1975 Checkerspot butterflies a historical perspective. Science 188:221-228. Emmel, T. C, and J. F. Emmel 1973 The Butterflies of Southern Califomia. Natural History Museum of Los Angeles County. ERC Environmental and Energy Services Co. (ERCE) 1990 Phase I Report, Amber Ridge, California Gnatcatcher Study. Prepared for Weingarten, Siegel, Fletcher Group, Inc. Faber, P. A., E. Keller, A. Sands, and B. M. Massey 1989 The Ecology of Riparian Habitats of the Southern California Coastal Region: a Community Profile. U.S. Fish and Wildlife Service. Biological Report 85(7.27). Franzreb, K. B. 1989 Ecology and Conservation of the Endangered Least Bell's Vireo. U.S. Department of the Interior, Fish and Wildlife Service. Washington D.C. Biological Report 89(1). Garrett, K., and J. Dunn 1981 Birds of Southern California. Artisan Press, Los Angeles. Grinnell, J., and A. Miller 1944 The Distribution of the Birds of California. Pacific Coast Avifauna 26:608. Jennings, M. R., and M. P. Hayes 1994 Amphibian and Reptile Species of Special Concern in California. California Department of Fish and Game. Rancho Cordova, Califomia. Jones, C. A., and R. S. Ramirez 1995 A 1995 Sighting of the California Gnatcatcher in Ventura County. Abstract. CalGnat '95: Symposium on the Biology of the California Gnatcatcher. University of California, Riverside. September 15-16, 1995. 24 Pike, J., S. Morris, V. Smith, and L. R. Hays 1995 The Status and Management of the Least Bell's Vireo and Southwestern Willow Flycatcher within the Prado Basin, California, 1986-1995. Prepared for The Nature Conservancy, Orange County Water District, U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service, and California Department of Fish and Game. RECON 1986 Draft Comprehensive Species Management Plan for the Least Bell's Vireo. Prepared for the San Diego Association of Governments. (Revised 1988.) 1989 Comprehensive Species Management Plan for the Least Bell's Vireo. Prepared for the San Diego Association of Governments. 1991 Biological Technical Report for Calavera Hills Master Plan Carlsbad, Califomia. Prepared for: City of Carlsbad. September. 2000 Biological Technical Report for the Calavera Hills Master Plan Phase H, Bridge and Thoroughfare District, and Detention Basins, Carlsbad, Califomia. Prepared for Planning Systems. May 10. Reiser, C. H. 1994 Rare Plants of San Diego County. Aquifir Press. Imperial Beach, California. San Diego Association of Governments 1993 Multiple Habitat Conservation Plan for Northern San Diego County. San Diego, City of 1994 Draft Multiple Species Conservation Program. Preserve map and text. Schoenherr, A. A. 1992 A Natural History of California. University of California Press. London. Sloan, A. J. 1964 Amphibians of San Diego County. Occasional Papers of the San Diego Society of Natural History No. 13. 25 Sweet, S. 1992 Initial Report on the Ecology and Status of the Arroyo Toad (Bufo microscaphus californicus) on the Los Padres National Forest of Southern Califomia, with Management Recommendations. Contract Report to U.S. Department of Agriculture, Forest Service, Los Padres National Forest, Goleta, Califomia. Revised March. Tibbitts, T. J., M. K. Sogge, and S. J. Sferra 1994 A Survey Protocol for the Southwestem Willow Flycatcher (Empidonax traillii extimus). Tech. Rep. NPS/NAUCPRS/NRTR-94/04. U.S. Dept. Int., National Park Service, Colorado Plateau Res. Sta., Flagstaff, Arizona. Unitt, P. A. 1984 Birds of San Diego County. Memoir No. 13, San Diego Society of Natural History. U.S. Fish and WildUfe Service 1994 Numbers and Distributions of Least Bell's Vireos, 1986-1994. Carlsbad Field Office. 1997 Coastal California Gnatcatcher Protocol for Presence/Absence Surveys. Carlsbad Field Office. July 28. 1999 Least Bell's Vireo Survey Guidelines. U.S. Department of the Interior, Fish and Wildlife Service. April 8. 26