Loading...
HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Calavera Hills Master Plan Phase II, Bridge Basin, District; 2001-01-25REVISED BIOLOGICAL TECHNICAL REPORT FOR THE CALAVJERA Fma.S MASTER PLAN PHASE TI, BRIDGE AND THOROUGHFARE DISTRICT, AND DETENTION BASINS CARLSBAD, CALIFORNIA Prepared far PLANNING SYSTEMS CONTACT: PAUL KLUKAS 1530 FAILWAY AVENUE, SUITE 100 CIUUSBAD, CALIFORNIA 92008 WENDY Em-- BIOLOGIST RECON NUMBER 3225B JANUARY ,25,2001 t 927 Fi Avenue, Suite 200 San Diego, CA 92101 619 I 308-9333 fax 308-9334 TABLE OF CONTENTS Summary of Findings Introduction Sumey Methods Existing Conditions A. Topography and Soils B. Botany C. zoology D. Sensitive BioIogical Resources E. Wetlands and Non-Wetland Jurisdictional Waters Project Impacts A. Plant CormnuIlities B. Wildlife C. Sensitive Biological Resources D. Jurisdictional Wetlands and Waters of the U.S. E. Wildlife Movement Corridors Mitigation Measures A. Sensitive Hant Communities B. Sensitive C. Jurisdictional Waters References Cited TABLE OFmCONTENTS (cont,) FIGURES Regional Locati0.n of the Project Project Vicinity Project Location Existing Biological Resouroes: Master Plan Phase II Existing Biological Resources: Bridge and Thoroughfare District and Detention Basins Existing Jurisdictional Waters of the U.S. Project Impacts: Mkter PIan Phase II Project Impacts: Bridge and Thoroughfare District and Detention Basins Project Impacts to Jurisdictional Waters of the U.S. Soil Types Within the Project Components Vegetation Communities Within the Project Components Sensitive Piant Species Observed w with the Potential for Occurrence Sensitivity Codes Sensitive Wildlife Species Known (or Potentially Occurring) Impacts to Resources by Village Within the Master Plan Phase II Project Component Impacts to Resources Within the Bridge and Thoroughfare Disirict Impacts to Resources Within the Detention Basins Project Component Mitigation for Impacts to Resources Within the Master Han Phase I1 Project Component Mitigation for Impacts to Resources Within the Bridge and Thoroughfare Diistrict - 1 1: Mitigation for Impacts to Resources Within tbe Detention Basins Project Component 1: Plant Species Observed 2: W11dlife Species Observed Summary of Findings The Cdavera Hills Master Plan Phase I1 and Bridge and Thoroughfare District No. 4 project is located in the northeast quadrant of the city of Cadsbad. The study area contains several sensitive plant communities including Diegan coastal sage scrub, riparian woodland, native grassland, riparian scrub, riparian forest, cismontane alkali marsh, cismontane alkali marsh (seasonal), and freshwater marsh. Two birds federally listed as threatened or endangaed, the coastal California gnatcatcher and least Bell's vireo, and one plant species Listed as endangered, thread-leaved brodiaea, were obswed omsite. The property also contains jurisdidonal wetlands and non-wetland jurisdictional waters of the U.S. Impacts to any of these sensitive resources would be significant and mitigation would be required. me impact analysis and recommended mitigation ratios in this document are based on the City of Carlsbad's Habitat Management Plan, which is currently in the process of being approved by regulatory agencies and adopted by the City. If this document is not approved as currently published or is not adopted by the City, the required mitigation recommended in this document may have to be revised and the project would be required to obtain applicable permits for impacts to listed species as per Section 1qa) or Section 7 of the federal Endangered Species Act. Introduction The project site is located in the northeast quadrant of the city of Carlsbad (Figure 1) and consists of three components: Calavera Hills Master Plan Phase II area, Bridge and Thoroughfare District No. 4, and two proposed detention basins @~s 2 and 3). Tbe Calavera Hills Master Plan area is bounded by State Route 78 (SR-78) on the north with the southern boundary being an east-west line approximately one-half of a mile north of the Rancho Carlsbad Mobile Home Park. Tbe Master Plan's western extent is near Carlsbad Village Drive. Figure 3 also shows the proposed extensions of CoLIes Boulevard and Cannon Road which are generally southeast of the Master Plan. The second major component of the project is the formation by the City of CarIsbad of a Bridge and Thoroughfare District No. 4 for the extensions of College Boulevard armd Cannon Rod College Boulevard would be extended from within the Calavera Kills Master Plan at Cdsbad Village Drive to El Carnino Real. It should be recognized that the Bridge and Thoroughfare District encompasses the reach of CoIIege Boulevard that lies within the boundaries of the Calavera Hills Master Plan. Cannon Road would be extended from El Carnino Real easterly to the city of Oceanside. Figures 2 and 3 shows the limits of the District and the approximate alignments of both roadways. Two alternative alignments for each roadway are also addressed in this report. The third component of the project consists of the construction of two detention basins (see Egwes 2 and 3) by the City of Carlsbad to control flooding impacts within CaIavera Creek watershed. These basins have been recommended near the' northeast corner of the , Rancho Carlsbad Mobile Home Park Basin 'BJB" is located north of the Colfege BoulevardfCannon Road intersection and would have an inundation area of approximately 15 acres and a storage capacity of 49 a-feet. Basin "W is located southeast of the College BoulevardCannon 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. A general biological swvey was conducted to map vegetation communities and to assess the presence or potential for presence of sensitive floral and faunal species. In ation, surveyx were conducted for the coastal Califomia gnatcatcher (Polwptih califomim califomica) and least Bell's vireo (Vireo beUii pusillus) according to U.S. Fish and Wildlife Service (LJSFWS) survey protocol. This report provides biological data and background information required for environmental analysis by the California Environmental Quality Act (CEQA). In addition, impacts were analyzed using information provided in the City of Carlsbad's Draft Habitat Management Plan (HMP). This document is currently in the process of being approved by regulatory agencies and adopted by the City. If Ifs document is not approved as currently published or is not adopted by the City, the required mitigation recommended in this document may have to be revised and the project would be required to obtain applicable permits for impacts to listed species as per Section 10(a) or Section 7 of the federal Endangered Species Act Survey 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 Wendy Loeffler, Jennifer Hodge, and Cynthia Jones. 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. The project components are not pgraphically exclusive and overlap where the College Boulevard alignment falls within the Master Plan boundary. Animal species observed directly or detected from calls, tracks, scat, nests, or other sign were notad All plant species observed on-site were also noted, and plants that could not k identified in the field were identified later using taxonomic keys. The wildlife surveys include focused surveys for coastal California gna~atchers conducted by RECON biologists Wendy bffler (permit number TS839084-2) and Cynthia Jon- (TE-811615) according to the USFWS California gnatcatcher survey guidelines (USFWS 1997a). 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 gnatcarehers, with mild temperatures and winds of 0 to 5 miles per hour. Focused suweys for the southwestern willow flycatcher were conducted by Cynthia Jones (TE-8 11615) on May 22, June 13, and June 23,2000, Suweys were conducted according to the accepted survey protocol (Sogge et d. 1997), which requires at lemt one survey between May 15 and 31, one survey between June 1 and 21, and one survey between June 22 and July 10. Focused surveys for least Bell's vireo were conducted on April 27; May 1 1 and 22; June 4, 13, and 23; and July 5 and 14, 2000 by Amy EZsnic and Cynthia Jones. Survey guidelines for these species require eight surveys, at least 10 days apart between April 1 and July 3 1 (USFWS 1999). A wetland delineation was performed by RECON biologist Jennifer Hdge according to the guidelines set forth by the U.S. Army Corps of Engineas (USACE 1987) on December 13, 1999, and January 5, 17 and 19, 2000. A wetland delineation is used to identify and map the extent of the wetlands and "waters of the U.S." found within the proposed project boundary and provide information regarding both state and federal jurisdictional issues. Several previous surveys have been conducted on the Master Plan area and a portion of the College Boulevard extension (RECON 1991 ; S weetwater Environmental Biologists, kc. [SEB] 1995). me biological information gathered during these surveys is incorporated into this report. Limitations to the compiIation of a comprehensive floral checklist were imposed by seasonal factors, such as blooming period and emergence of spring annual species. Faunal species, such as birds and butterflies, that are only present during the breeding season of late spring-to summer were not detected. Since surveys were performed during the day, nocturnal anids were detected only by sign. Fld nomenclature for common plants follows Hickman (1993). Plant community classifications follows the Draft Habitat Management Plan for the Natural Communities in the City of Carlsbad (City of Carlsbad 1999). Zoological nomenclature for birds is in accordance with the American Ornithologists' Union Checklist (1998); for mammals, Jones et al. (1982); and for amphibians and reptiles, Collins (1997). Assessments of the sensitivity of species and habitats are based primarily on Skinner and Pavlik (1 9941, State of California (1499% 1999b, 1999c, 2000), City of Carlsbad (1999), and Holland (1986). Existing Conditions Topography and Soils Elevation of the entire site ranges from approximately 40 to 500 feet above mean sea level (U.S. Geological Survey 1968). A small portion of Agua Hedionda Cmk-is present within the College Boulevard extension south of the intersection with the proposed Cannon Road. Several unnamed drainages flow north-south info Agua Hedionda Creek The site contains several hills surrounding the flat agricultural fields. Several of the hillslopes support rock outcrops. There are 21 soil classifications present within the entire project area (U.S. Deparbnent of Agriculture 1973). Table 1 presents the list of soil types and where within the three projsct components each type is located. There are two different clay soil series press on-site: Altamont clay and Diablo clay. There are 12 different loam soil series present, which include Ioams, sandy loams, cobbly loams, and clay loarns. The loam soils are represented by Huerhuexo lorn. The sandy loams are represented by many different soil series: Bonsall sandy loam, Cieneba very mky coarse sandy loam, Cieneba-Fallbrook rocky sandy loam, Escondido very fine sandy loam, Fallbrook rocky sandy loam, Friant rocky fine sandy loam, Gaviota fine sandy loam, and Las Posas stony fine sandy loam. The clay loam represented is Olivenhain cobbly loam and the clay loam is Salinas clay loam. There are four sand and loamy sand soil series present on-site: Carlsbad &avellY loamy sand, hs Flores Iomy fine sand, Marina loamy coarse sand, and Tujunga sand. The remaining three soil types present are loamy alluvial land-Huerhuem complex, riverwash, and steep gullied land. Botany Eleven vegetation communities were identified within the survey area! Diegan coastal sage scrub, southern mixed and chamise chaparral, non-native grassland, ripariap 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 agriculture, developed, or disturbed Table 2 presents the acreages of each community within the project components. There is a total of 412.6 acres within the Master Plan Phase II project component and a total of 421.2 acres within tbe Bridge and Thoroughfare District and detention basin areas. This existing acreage for the roadways reflects a survey area that includes a 500-foot corridor on both sides of the alignments. These project components are not geographically exclusive and overlap where the College Boulevard alignment fdIs within the Master Plan boundary. figure 4 illustrates the locations of the plant communities within the Master Plan Phase II area and Figure 5 illustrates the vegetation within the Bridge and Thoroughfare District and detention basin areas. A total pf 116 plant species were identified on the site (Attachment I). Of this total, 70 (60 percent)'are species native to southem California and 46 (40 percent) are introduced species. 1 Diegan Coastal Sage Scrub Diegan coastal sage scrub is the dominant vegetation community within the Master Plan area and the Bridge and Thoroughfare Dislrict and detention basin areas. Them are approximately 250.3 acres within the Master h phase 2 area and 137.3 acres within the survey area of the Bridge and Thoroughfare DistricrlDetention Basins. Much of the community is domid by California sagebrush (Artemisia calij'umica) and California adolphia (Adolphia cuZij%mica). These areas tend to intergrade with areas dominated by black sage (Salvia mellvera) and California buckwheat (Enbgonum fasicularm var. fasciculm). Other areas, generally within or adjacent to the many small drainages on- site, are dominated by coyote bush (Baccharis pilularis). Other common species include laurel sumac (Malosma lauriraa.), lemonadeberry (Rhs iretegrifoia), common encelia (Encelia califomica), blue elderberry (Sambmus nnexicana), and bladderpod (Isomeris dorm). Understory species included both native and non-native species, such as purple needlegrass (Nassella p ulch ra), slender stephomeria (Stephanomeri~ virgatu), coast goldenbush (Isocoma mmiesii) , white- stemmed filaree (Erodiurn cicutarim), golden- yamow (Enbphyllum cmfertiJIonun), wild oats (Aveuaa sp.), and California broom (Lotmcs scuparius). 2. Southern Mixed and Chamise Chaparral Chaparral is present on approximately 66.6 acres of the Master Plan area and approximately 24.8 acres of the Bridge and Thoroughfare District and detention basin areas. The majority of the chaparral is dominated by laurel sumac, lernonadek~~y, coast blue lilac (Ceanothus tomentosus), chamise (Ademstom califomica), toyon (HeteromeIw ~rbutfolia), and black sage. Several areas of chapd were dominated by chamise. Much of the understory consists of typical coastal sage scrub species, such as California adolphia, California sagebrush, coyote bush, and California buckwheat. The soils that underlie this community are primarily loam and sandy loans. The site does not contain the sandstone soils required to support southern maritime chaparral (City of Carlsbad 1999). 3. Non-Native Grassland Approximately 20.2 acres of the Master Plan area and approximately 16.3 acres of the Bridge and Thoroughfare District and detention basin areas are covered with non-native grassland This plant community is dominated by non-native grasses such as wild oat, ripgut grass (Bromus diandnrs), foxtail chess (B. madritensis ssp. rubens), and smooth brome (B. Rordmeus). Herbaceous species, such as black mustard (Brassica nigra), white-stemmed filaree (Erodim cicutarim), and western ragweed (Ambrosia psilostachya) were also common in these amas. Riparian Woodland Approximately 0.2 acre of riparian woodland is pment within the Master Plan area and approximately 15.1 acres are present within the Bridge and Thoroughfare Disaict and detention basin areas. These areas are lcated along a portion of ~alavera Agua Hedon& Creek, and an unnamed drainage. Western sycamom (Plafartus racema) dominate the plant community with understory species composed of the native mugwort (Artemisia duuglasiaPza) and jimson weed (Dafum wrighiii), d ncm-native plants, including giant red (Arundo donax), horehound (Mamrbim vulgare), castor bean (Ricinus communis), and poison hemlock (Conim maculattm). *.i . 5. Eucalyptus Woodland Eucalyptus woodland is present on approximately 9.9 acres of Village H in the Master PIan asea and scattered in a few small patches totaling 5.0 acres within the Bridge and Thoroughfare District area. This plant community is dominated by eucalyptus irees (Earca&tus spp.) and has a groundcover ?hat ranges hrn bam to mhhd cover with non-native grasses, such as wild oats, ripgut grass, and smooth brome. Native Grassland Native grasslands are comprised of native perennial bunch grasses. This plant community has been mainly converted to non-native annual grassIands due to the invasion of exotic annual gasses. Native grasslands often have s large component of noo-n'atlve grasses but are distinguished as native when the cover by native grass species is 10 percent or greater. Native grassland was primarily found in Village H of the Master Plan area on appmxirnately 9.3 acres. Riparian Scrub Approximately 7.2 acres of riparian scrub are present within the Master Plan area and 3.3 acres are present within the Bridge and Thoroughfare District detention basin areas. Tbe community designation includes both mule fat scrub and southern willow scrub habitats found along many of the drainages on-site. Mule fat (Baccharis saIicifolia) and coyote bush dominate with giant red, pampas gass (Cortadenb jubnta), and curiy-dock (Rumex crispus) commonly presenL The southern willow scrub is dominated by amyo willow (Sdk hiolepis), which forms a canopy with variable density throughout the site. Other associated trees include red willow (Salk lmvigata), black willow (S. gooddingii), wcstem sycamore and Mexican fan palm (Washingtonia robusta). The understory includes mule fat, tdl yellow evening primrose (Oenothera elata ssp. himtissim), giant wild rye (Le~s con&nsams), tall flatsedge (Cypems eragrostis), rue (JURCUS sp.), and curly dock. 8. Riparian Forest Riparian forest, defined as southern coast live oak riparian forest, is a habitat that is found in drainage bottoms often intergrading with riparian scrub and woodland habitats. Approximately 2.0 acres of this habitat is locd dong the creek the flows within the Cannon Road alignment of the Bridge and Thoroughfare District. The dominant tree is the coast live oak (Quercus agrifolia), with a variable understory of freshwater marsh habitat, as described below, and other species that include poison oak (Tox*coddrm diversiloburn), coyote bush, and toyon. 9. Cismontane Alkali Marsh Two small patches of cismontane alkali marsh totaling 1.0 acre are present within the Bridge and Thoroughfare District. This habitat is characterized by the pmsence of wetland species, such as spiny rush (Jmus acutus ssp. Ieopoldir*), yerba mansa (Anempsis califomica), salt grass (Distichlis spicata), spikmsh (Eleocharis sp.), and alkali heath (Frunkenia salim). I 10. Cismontane Aikali Marsh (seasonal) Seasonal cismontane alkali marsh defines small patches of vegetation that are currently ' dry but are dominated by wetland plants. These areas are generally located at the upper end of small erosional drainages. There are several small patches totaling 05 acre within the Cannon Road alignment within the Bridge and Thoroughfare District and one 0.1-a- patch within the Master Plan area. The dominant plants include several species of rush . (Juncus spp.). 11. Freshwater Marsh Approximately 0.5 acre of freshwater marsh is present in a drainage within the Master Plan area and an approximately 0.2-acre patch is present within the alignment of College Boulevard just below El Carnino Red. There is also a small isolated patch of freshwater marsh at the approximate intersection between the College and Cannon road alignments. This community is dominatd by broad-leaved cattails (Typha latifolk), including also rush, pampas grass, giant reed, and tall flatsedge. 12. Agriculture Much of the Bridge and Thoroughfare District area is under cultivhon. These fields account for approximately 133.6 acres of the survey area. This designation is used for the approximately 25.8 acres in the Master Plan area and 54.1 acres in the Bridge and Thoroughfare District detention basins area. Developed includes the lnss converted to housidg, pgved roads, a other structures. These amm contain some landscaping, including palm treg and Hottentot fig (Carpobronrs em*j). 14. Disturbed This designation is used primarily for areas that have been graded or are dominated by non-native weedy +a. The plants present here include fennel (Foeniculm vulgare), black mustard, ripgut grass, smooth brome, bristly ox-tongue (Plcris echioides), and Bermuda grass (Cynodon &ctylon). There are approximately 22.5 acres in the Master Plan area and 28.0 acres in the Bridge and Thoroughfare DistrictlDetention Basins area C. zoology Overall, the project m and vicinity provides high value habitat for wildlife species. Much of the site contains moderate to high-quality coast$ sage and chaparral habitat and high-quality riparian habitats, which provide cover, foraging, and breeding habitat for a variety of native wildlife species. A complete list ' of the wildlife species detected is provided in Attachment 2. Sensitive species potentially occurring on-site are discussed in the Sensitive Biological Resources section. 1. Amphibians Most amphibians quire moisture for at least a portion of their life cycle, with many requiring a permanent water source for habitat and reproduction. Terrestrial amphibians have adapted to more arid conditions and are not completely dependent on a perennial or standing source of water. These species avoid desiccation by burrowing beneath the soil or leaf litter during the day and during the dry season. Pacific treefrogs (&la regilla) were-heard within the drainages and wetlands throughout the Pwem- 2. Reptiles The diversity and abundance of reptile species varies with hfiitat type. Many reptiles are restricted, to cdn vegetation communities and soil types although some of these species will also forage in adjacent communities. Other spies are more ubiquitous using a variety of vegetation types for foraging and shelter. No reptiles were observed on-site during the current surveys. A number of species have been identified previously on the site including San Diego gopher snake (Pimophis catenveer mnecterts), San Diego horned lizaxd (Phynosoma coronam blainvillii), westem fence' Iizkd (SceZoponis orcidcn frrlis), side-blotched lizard (Utrr stiansbun'm), and Belding's orangethroat whiptail (Cnernidophorus hyperytkrtrs beldingi) WON 1991; SEE 1995). 3. Birds The diversity of bird spe.cies varies with rapect 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 obswved within the Diegm coastal sage scrub and southern mixed and chamise chap& include Bewick's wren (Thyronmes bewickii), bushtit (Psdtripalzrs mihimus minim), yellow-rumped warbler (Dendroica coronata), wrentit (Chumaea fmciafa), Anna's hummingbird (Calypte annu), California towhee (Peilo misscalis), spotted towhee (P. rnuculatw), and California quail (CdlipepLa caZifbmica). Birds commonly found in the riparian habitats include lesser goldfinch (Carduelis tristis salic-1, Nuttall's woodpecker (Dsndrocopos nunallii), bushtit, common yellowthroat (Geothlypis m'ckas), song sparrow (Melospiza melodia), and yellow-rumped warbler. Mouming dove (Zkmida mcacroura marginella), kingbird (Tyrannus sp.), house finch (Carpodc~cus mexicanus frontalis), and western meadowlark (Sturnella negteeta) were commonly observed within the native and non-native grasslands. Raptors observed on-site include . red-tailed hawk (Buteo jamaicensis), red-shouldered hawk (Buteo liiwatus eiegans), northern harrier (Circus cymeus hudsonius), turkey vulture (Catharta aura), white-Wed kite (Ehw leucurus), American kestrel (Falco spawerim), and Cooper's hawk (Accipiter coopcrii). A common barn ow1 (Tyfo ah pmtincoh) carcass was found in the coastal sage scrub in Village H. Nesting habitat is present on-site for these species and other raptm in the riparian habitats. Coastal sage scrub, chaparral, woodland, and riparian cornmumties typically provide cover and foraging opportunities for a variety of mammal species. Many mammal species are nocturnal and must be detected during daytime surveys by observing their sign, such as tracks, sc* and burrows. Cottontail rabbit (SyIvilagw audubonii), southern pocket gapher (Tkomrnys umbnitus), woodrat (Neotoma sp.), and coyote (Canis btrans) were observed either directly m througb sign. San Diego black-tailed jackrabbit (Lapus califimicus bennem'i?) was also observed during previous surveys (RECON 199 1; SEB 1 W5). D. Sensitive Biological Resources State and federal agencies mgulate sensitive species and require an assessment of their presence or potential presence to be conducted on-site prior to the approval of any proposed development on a property. For purposes of this report, species will be considered sensitive if they m: (1) listed or proposed for listing by state or federal agencies as threatened or endangered; (2) on List 1B (considered endangered throughout its mge) or List 2 (considered endangered in California but more common elsewhere) of the California Native Plant Society's (CNPS) Inventory of Rare ad Endwagered Vascular Plants of California (Skinner and Pavlik 1994); (3) included on the Draft Habitat Management Plan @IMP) or Multiple Habitat Conservation Program (MHCP) list of species evaluated for coverage or list of narrow endemic plant species; or (4) considered fully protected, sensitive, rare, endangered, or threatened by the State of California (1999a, 1999b, 1999~) and Natural Diversity Data Base (NDDB) (State of California 2000), or other local conservation organizations or specialists. California fully protected is a designation adopted by the State of California prior to the creation of the State Endangered Species Act and is intended as protection from harm or harassment. Noteworthy plant species are considered to be those which rn on List 3 ' (more information about the plant's distribution d rarity needed) and List 4 (piants of limited distribution) of the CNPS Inventory. Sensitive habitat types are those identified by the NDDB (State of California 2000), Holland (1986) andlor those considered sensitive by other resome agencies. The MHCP is a comprehensive, multi-jurisdictional habitat conservation plan currently being drafted far northwestern San Diego County (San Diego Man of Governments [SANDAG] 1998). In addition to the City of CPdsb.4, participating ' jurisdictions include the cities of Oceanside, Vista, San Marcos, Escondido, Encinitas, and Solana Beach. The City of CarIsbad has drafted the Draft Habitat Management Plan for Natural Communities in the City of Carlsbad (HMP), a subarea plan of the MHCP (City of Carlsbad 1999). The City's Draft EMF designates a natural habitat preseme system and provides a regulatory framework for determining impacts and designating mitigation associated with proposed projects. In the event the Draft HMP is not formally approved and adopted, all projects would be required ta obtain applicable permits for impacts to listed species as per Section 1qa) or Section 7 of the federal Endangered Species Act. The multi-jurisdictional MHCP draft document identifies a series of focused planning areas within which some lands will be dedicated for preservation of native habitats. These ms contain both %ad line" areas which will be preserved as open space and "soft line" areas which will include both development and open space to be determined through the planning process. Mitigation requirements for impacts to the biological resources are based on ratios provided by the Draft HMP (City of Carlsbad 1999). If this plan is not formally adopted, these mitigation requirements may need to be revised. Determination of the potential occurrence for listed, sensitive, or noteworthy species me based upon known ranges and habitat preferences for the species @kine1 et al. 1988% 1988b, 1990; Skinner and Pavlik 194; Reiser 1994); species occurrence records from the NDDB (State of California 20); and species occurrence recd from other sites in the vicinity of the project site. 1. Sensitive Plant Communities and Habitats The following communities identifisd on-site are considered sensitive by the City of Carlsbad (19991, NDDB (State of California 20001, Holland (19861, ador state and federal resource agencies: Diegan coastal sage scrub, native grassland, riparian woodland, riparian scrub, riparian forest, cismontane alkali marsh, cismontane alkali marsh (seasonal), and freshwater marsh. I a. Diegah Coastal Sage Scrub Diegan coastal sage scrub is restricted to the coastal areas of southern CaLifd and northern Baja California. Development and other human-relatd activities have seriously impacted this plant community and its associated plant and wildlife species. It is estimated that 70-90 percent of the presettlement southern California coastal sage scrub has been destroyed, with the losses accelerating rapidly within the last &ade moss et d. 1995; Sawyer and Keeler-Wolf 1995). Diegan coastal sage scrub is considered sensitive by federal and state resource agencies, most southem CaIifornia jurisdictions, lccal conservation organizations, and the City of Carlsbad. This plant community is occupied by the coastal California gnatcatcher based on biological studies conducted in 1992, + 1995, and 1999 that have noted the presence of this species within the Master Plan Phase II, Bridge and Thoroughfare District survey areas, and the Calavera Nature Preserve WON 1991; SEB 1995). b. Native Grassland Native grasslands are. considered sensitive because of the extensive Im of this community throughout the state. Native grasslands are listed as sensitive by the City of Carlsbad (19991, Holland (1986), and NDDB (State of California 2000) and it is estimated that only 0.1 percent of the native grasslands in California remain (Keeley 1990). Tbe loss of native grasslands is attributed to development, agriculture, grazing, and invasion by non-native, annual grasses and other non-native plant species. The invasion of native grasslands by non-native species including brome grasses (Brow spp.), wild oats, and mustards h+s degraded native grasslands to the extent that it is rare to find any that have not been invaded by these species. Grasslands that have 10 percent cover by native grasses such as needlegrass are classified hue as native grasslands. c. Riparian Woodland, Riparian Scrub, and Riparian Forest AU riparian communities are coAsidem3 sensitive by the City of Carlsbad and are regulated as sensitive wetland habitats by the California Department of Fish and Game (CDFG) and U.S. Army Corps of Engineers (USACE). These plant communities are found along rivers, streams, and intermittent drainages throughout southern California. ChanneIization of rivers, streams, and drainages for flood control and land development has resulted in curnulatiqe losses of these habitat types tbroughout the state. The loss of riparian habitats in southern California has been estimated at greater than 95 percent Cr:aber et al. 1989). Riparian scrub, in particular, potentially supports several endangered and otherwise sensitive wildlife species. d. Cismontane Alkali Marsh and Cismontane Alkali Marsh (Seasonal) Cismontane alkali marshes are typically low-lying areas with a high water table that have alkaline soils. Evaporation of ponded water often results in salts remaining on the surface. This plant community is identified as sensitive by the City of Carlsbad (1999), Holland (19861, and NDDB (State of California 2000), and is considered a sensitive wetland community by USACE and CDFG. Wetland communities have been greatly reduced throughout their entire range and continue to decline as a result of urbanization. State and federal resource agencies consider wetland communities to be sensitive plant communities. Freshwater Marsh Freshwater marsh vegetation occurs in open bodies of fresh water with little current flow, such as ponds, and to a lesser extent around seeps and springs. This plant community is identified as sensitive by the City of Carlsbad (1999), Holland (1986), and NDDB (State of California 2000), and is considered sensitive as a wetland community by USACE and CDFG. Freshwater marsh communities, as with all wetland habitats, have been greatly reduced throughout their entire range and continue to decline as a result of urbanization and are considered sensitive by state and federal resource agencies. 2. Sensitive Plants Seven sensitive plant species were observed on-site during the most recent surveys conducted by RECON in 1999 and during previous surveys conducted in 1991,1992, and 1995 (RECON 199 1, SEB 1995). One plant that is federally and state listed, three sensitive plant species, and three noteworthy plant species were observed on-site: thread- leaved brodiaea (Brodiaea ftlifolia), Nuttall' s scrub oak (Quercus dumscm), California adolphia, Palmer's grapplinghook (Harpugonella pahri var. paLmeri), spiny rush (Juncus mtus ssp. le~~~dii),' western dichondm (Dichondr. orcidentdis), and ashy spike-moss (Selaginella cimruscerrs). figures 4 and 5 show the locations of thread-leaved brodiaea, Palmer's grapphghoo~ and Nuttall's smb o& California adolpbia, spiny rush, and ashy spike-moss were common within their respective habitats throughout the sik and were not mapped. Previously observed plant locations are expected to still be valid data becaux the sd and vegetation has not been substantially altered during the interim. The extent of plant populations in density and area can fluctuate from year to year based on environmental conditions; however, species are still expected to be present at their previously recorded locations. a. Observed Plant observations are from both the current and previous surveys (RECON 199 1; SEB 1995). Thd-leaved brodiaea (BroGiaea @$oh). Thread-leaved brodiaea is a state endangem and a federal threatened listed species, a Draft HMP and MHCP covered species, and a CNPS List 1B species. This perennial corm typically occurs on hillsides or valleys in grassland communities with clay, loamy sand, w alkaline silty-clay soils (USFWS 1994). Tbe blooming period for thread-leaved brodiaea is from May to June. A population of this species is present within the grassland and sage scrub habitat on tbe northern portion of Village H, Approximately 300 individuals within 1,700 square meters was originally mapped by RECON biologists in 1991 (RECON 1991). The population was reidentifid in 1995 when 200 individuals were observed (State of California 2000). This decrease in flowering plants does not show a decline in the number of individuals present. Year to year variations in numbers of individual flowering can occur due ta changes in environmental conditions (e.g., rainfall). Nuttall's scrnb oak (Qwrcus dumosa). Nuttall's scrub oak, a Draft HMP and MHCP covered species and a CNPS List 1B species, is a coastal chaparral shrub that can occur witb an open canopy or in dense stands. It is identifiable all year, as it is an evergreen. The geographic range of Nuttall's scrub oak spans from a few locations in southem Orange County south to he middle of Baja California. Urban development along the coast is the primary cause of its decline in San Diego County. This shrub was idensed in the southern mixed and chamise chaparral habitat in the Calavera Nature Preserve within the Master Plan area during the 1W9-2000 surveys. California adolphia (AdoIphia califomica). This shrub is a CNPS list 2 species that generally occurs in Diegan coastal sage scrub, often associated with California buckwheat and California sagebrush. It is apparent all year by its unique spiny stems. Its geographic range includes San Diego County south into Baja California. California adolphia is present and often a dominant species within the Diegan coastal sage scrub and southem mixed and chamise chaparral throughout the Master Plan and Bridge and Thoroughfhre 4 Districtareas. Palmer's grapplinghook (Haqagonsk pahen var. palPnm3. Palmer's grapplinghook is a CNPS List 2 specie. This small herbaceous annual is found iq day soils in caastal sage scrub, chaparral, and valley grasslands in southern Califha, including Lus Angeles, Orange, Riverside, and San Diego Counties, into Baja California, Arizona, and Sonora, Mexico. It is an inconspicuous plant that can be easily overlooked The flowering period is hm March through April. The species is threatened by development. Palmer's ppplinghook was observed in two small patches in Diegan coastal sage scrub within the open space north of Village U of the Master Plan area (RECON 1991). Spiny rush (Juncw ucutacs ssp. kopoU3. Spiny rush is a CMPS List 4 species. It is a large bushy rush commonly found in marsh habitats throughout San Diego County. It can be found in a variety of soil types at low elevations wherever ponded water or saturated soils are present, and is apparent year-round. Its range includes areas in Santa Barbma, Orange, San Diego, and Riverside Counties, into mainland Mexico and Baja California. This species is common in the cismontane alkali marsh habitat within the Cannon Road alignment aad detention basins survey areas. Western dichondra (Dikhnlkrr ace&&). Westem dichondra is a CMlPS List 4 ' species usually found growing under brush or trees in coastal sage scrub, chapand, or oak woodland areas. It grows primarily in dry sandy soils ranging from Orange County south into Baja California, Mexico. It is apparent from March to May. The numbers of western dichondra are in a slow decline in southern California. This species was observed . in several place in the Master Plan area and on the College Boulevard alignment Wng previous smeys (RECON 1991; SEB 1995). Ashy spike-moss (SelaginetCa cinermcens). This species is a CNPS List 4 promate perennial that is apparent yea-round. Its range includes Orange and San Diego Counties in California, south into Baja California. Ashy spikemoss is declining due to urban development. It was identified throughout the site in the Diegan coastal sage scrub and the charnise-dominant patches of the southern mixed and charnise chaparral within the Master Plan Phase II area and Bridge and Thoroughfare District areas. b, Not Observed Several other sensitive species are known to occur in the vicinity of the project site and are considered as potentially occurring on-site based on vegetation communities identified. Table 3 summarizes the status, habitats, and results of the botanical swey for each of these potentially occurring species, with codes explained in Table 4. Many of