HomeMy WebLinkAbout1997-04-22; City Council; 14157 Exhibit 1; Carlsbad Habitat Management Plan Environmental Impact ReportTABLE OF CONTENTS I
1
I
I
1
I
I 1.2.6 Sensitive Biota ..........................................
I
I
I
I
1
I
1
I
I
1
I
I
Section
OVERVIEW
1
..........................................................
SAN DIEGO COUNTY, CALIFORNIA: THE REGIONAL SETTING ...........
1.1 Introduction ..................................................
1.2 Existing Conditions .............................................
1.2.1 Regional Overview
1.2.2 Topography ............................................ 1.2.3 Climate ...............................................
1.2.4 Geology and Soils 1.2.5 Plant Communities .......................................
1.3 Summary and Conclusions ........................................
.......................................
........................................
2 CITY OF CARLSBAD: THE LOCAL SETTING ...........................
2.1 Introduction ... :. .............................................
2.2 Existing Conditions .............................................
2.2.1 General Topography and Landscape Features .................
22.2 Climate ..............................................
2.2.3 Geology and Soils 2.2.4 Plant Communities ......................................
2.2.5 Sensitive Biota .........................................
3 RESOURCE INVENTORY AND MAPPING .............................
.......................................
3.1 Introduction
3.2 Mate~als
3.3 Methods ....................................................
3.4 Results
.................................................
....................................................
..................................................... 3.4.1 Vegetation Map ........................................
3.4.2 Sensitive Species Map ...................................
.. 11
TABLE OF CONTENTS (Camtinued)
Page
4 BIOLOGICAL PRESERVE PLANNING AREA ANID DESIGN APPROACH ........ 36
4.1 Introduction .................................................... 36
4.2 Preserve Design Literature Review ................................... 36
4.2.1 Size .................................................... 36
4.2.2 Shape ................................................... 37
4.2.3 Isolation/Wildlife Corridors ................................... 37
4.2.4 Buffers and Distance Setbacks ................................ 37
4.2.5 Other Considerations ....................................... 40
Preserve Design Rationale and Approach .............................. 40
Preserve Design Methodology ....................................... 41
4.4.1 Focused Planning Areas ..................................... 41
4.4.2 Preserve Feature Definitions and Ratings .- Habitat Value ........... 42
4.4.3 Preserve Feature Definitions and Ratings .- Habitat Sensitivity ........ 45
4.5 Results -- Habitat Value ........................................... 47
4.5.1 Amount of Natural Habitat .................................. 48
4.5.3 Habitat Connectivity ........................................ 49
4.5.4 Adjacent Land Use ........................................ 49
4.5.5
Discussion -- Habitat Value ......................................... 50
Results -- Habitat Sensitivity ........................................ 50
4.7.1 Amount of Sensitive Habitat ................................. 51
4.7.2 Sensitive Habitat Diversity ................................... 51
4.7.3 California Gnatcatcher ...................................... 51
4.7.4 Sensitive Plants ........................................... 52
4.7.5 Sensitive Wildlife .......................................... 52
4.7.6 Composite Habitat Sensitivity ................................. 52
4.3
4.4
4.5.2 Habitat Diversity ........................................... 48
Composite Habitat Value .................................... 49
4.6
4.7
4.8 Habitat Sensitivity -- Discussion ..................................... 53
4.9 Total Habitat Value/Sensitivity .- Results ............................... 53
............................. 54
........................................... 55
4.10 Total Habitat VaIue/Sensitivity -- Discussion
4.11 Limitations of Approach
... 111
TABLE OF CONTENTS (Continued) I
1
8
I
I 5.2.2 Results ................................................
I
I
I.
1
I
I
i)
I
1
I
1
I
1
5 PRESERVE RECOMMENDATIONS ....................................
5.1 Introduction ..................................................
5.1.1 Size of Preserve System ...................................
5i2.1 Methods.. ............................................. 5.2 Potential Core Preserve Areas ....................................
5.3 Potential Wildlife Corridors ......................................
5.3.1 Methods.. .............................................
5.3.2 Results ................................................
5.4 Conceptual Preserve System .....................................
Compatible Land Use Analysis .................................... 5.5
5.6 Conclusion ...................................................
6 ACKNOWLEDGEMENTS ......................... :. ..................
7 LITERATURE CITED ...............................................
Appendices
k Federal and State Designated Sensitive Plant and WildliEe Species Resident or
Breeding in San Diego County
Environmental Impact Reports and Other Documents Consulted
1
B.
iv
TABLE OF CONTENTS (Continued)
LIST OF TABLES
Page
1 .
2 .
3 .
Comparison of Pre-European and 1988 Vegetation Coverage for San Diego
County .............................................................. 5
Classification System for Habitat Communities Occurring in the City of Carlsbad ..... 12
Acreages by Aggregated Vegetation Types within the Carlsbad Habitat Management
Plan Study Area ...................................................... 34
4 . Frequency Distribution for Habitat Value Features ........................... 48
Composite Habitat Value ............................................... 50 6 . Frequency Distribution for Habitat Sensitivity Features ........................ 51
Total Habitat Value/Sensitivity Frequency Distribution ......................... 54
Listing Preserve Planning Areas .......................................... 58
Listing Preselve Planning Areas .......................................... 60
5 .
7 .
8 .
9 .
10 .
11 .
12 .
Composite Habitat Sensitivity ............................................. 53
Acreages by Aggregated Vegetation Types for the F’re-California Gnatcatcher
Acreages by Aggregated Vegetation Types for the Fost-California Gnatcatcher
Pre-California Gnatcatcher Listing Preserve Planning Area Sensitive Species
Records ............................................................ 63
Post-California Gnatcatcher Listing Preserve Planning Area Sensitive
Species Records ...................................................... 64
LIST OF FIGURES
Follows
Page
1 . Regional Map ........................................................ 2
3 . Vegetation Map ..................................................... 33
Sensitive Species Map (Sheets 1 & 2) ...................................... 35
Pre-Gnatcatcher Listing Focused Planning Areas ............................. 41
6 . Post-Gnatca tcher Listing Focused Planning Areas ............................ 41
7 . Habitat Value Map ................................................... 49
8 . Habitat Sensitivity Map ................................................ 52
Total Habitat Value/Sensitivity Map ....................................... 53 10 . Pre-Listing Proposed Preserve Planning Areas/Corridors ....................... 57
2 . VicinityMap ........................................................ 10
4 .
5 .
9 .
11 . Post-Listing Proposed Preserve Planning Areas/Corndors 57 .......................
V
OVERVIEW
THE CARLSBAD HABITAT MANAGEMENT PLAN
1
1
8
1
1
I
I
1
I
I
1
1
1
1
I
I
I
At the direction of the Carlsbad City Council, the Community Development Departmer
undertaken preparation of a Habitat Management Plan (HMP) for the City. The goals of the p
are to develop an HMP that will: (1) constitute a major component of the Conservation El
of the General Plan; and (2) result in implementation of a plan that will plroactively a
protection of sensitive plant and animal species and their habitats as development occurs in Ca
The HMP will provide direction about how best to identify, conserve, use, and manage the
biological habitat resources and should result in an effective habitat preserve system. Del
regarding the design of the preserve system will be based on scientific theory and be consister
current knowledge from the field of conservation biology.
A broadly based Citizens Advisory Group that contains representatives of land owners, environ
groups, state and federal regulatory agencies, and City operating departments provides inp
I
1 oversight to .the project.
1
S E C T.I 0 N
SAN DIEGO Coum: CALIFOE
Th
\
I
,
I
-
BIOLOGICAL RESOURCES AND HABITAT AN
in supportofthe ClTY OF CAlUSBAD HABI'IAT MANAGEMENT PLAN
SECTION 1
SAN DIEGO COUNTY, CALIFORNIA
THE REGIONAL SETTING
1
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1.1 INTRODUCTION
This section provides an overview of the regional setting in which the HMP is being dew
Other jurisdictions within San Diego County are currently undertaking or considering similar 1
resources planning programs. While Carlsbad’s plan is intended only to address land and h
within its corporate limits, it is important in formulating such a plan to be aware of regional
and other programs. As such, the Carlsbad HMP is intended to be consistent with three
subregional programs -- the San Diego Clean Water Program Multi-Species Coriservation PI
(MSCP), the County of San Diego Open Space and Habitat Management Plan (OSHMP), a
North County Multiple Habitat Conservation Program (MHCP), as well as the anticipated (
County Wildlife Forum Plan. The plan also is intended to be consistent with the pilot P
Communities Conservation Planning (NCCP) for coastal sage scrub habitat in Southern Cali
This state program, if successful, would provide regional resource planning and prlotection for
sage scrub and its threatened plant and wildlife species. I 1.2 EXISTING CONDITIONS
1.2.1 REGIONAL OVERVIEW
San Diego County, California, is the most southwesterly county in the continental United St;
is bordered on the east by Imperial County, on the north by Riverside and Orange counties,
west by the Pacific Ocean, and on the south by Baja California, Mexico (Figure 1). R
trapezoidal in shape, it extends about 70 miles (110 km) from east to west and 60 miles (80 kn
north to south; it covers approximately 4,250 square miles (7,000 square km). Ekvations ran$
sea level along the coast to 6,533 feet (2,000 m) at the highest point -- Hot Springs Mounta
Warner Springs.
San Diego County supports an exceptionally diverse biota (Le., the animal and plant speci
region): over 1,500 species of plants (Beauchamp 1986), 160 breeding and about 275 non-bi
species of birds (McCaskie 1977), 75 species of reptiles and amphibians (Lichtwardt and Golc
125 resident species of butterflies (Brown 1991), 80 species of mammals (Bond 1977),
estimated 10,000 to 20,000 species of terrestrial and aquatic invertebrates. A number of
combine to support this rich biodiversity, including varied topography, complex climatic cor
a wide variety of soil types, and a unique biogeographic history.
San Diego County is also one of most rapidly-growing areas of the country. Because the <
human population expansion and habitat change are occurring primarily along the coast wh
most sensitive biological resources occur, the conflicts of growth and maintenance of bi
diversity are acute. Planning has not previously been done on a regional scale for this area r
in a highly fragmented natural landscape. This, in turn, makes preserve design more diffic
necessitates designation or creation of wildlife corridors to interconnect habitat fragments.
1.2.2 TOPOGRAPHY
Physical features found along the western edge of the county include sandy beaches, wic
floodplains, low-lying salt marshes, and rocky bluffs. These areas support coastal dune, coa
I
2
Riverside County
WARNER
WR
Sff
DESC~SO
mwAR D
EnUU VISTA /
e
No $
-I
Carlsbad Habitat Management Plan
marsh, Torrey pine woodland, and maritime succulent scrub plant communities. Inland from thl
a series of coastal mesas, foothills, and canyons support coastal sage scrub, southem mixed cha
chamise chaparral, and oak and riparian woodland communities. Further inland are the foot
the Peninsular Range Mountains, covered primarily with chamise chaparral, southe m mixed cha
and oak woodlands. Riparian woodlands occur along watercourses. The county is bisected ne
south by an extension of the Peninsular Ranges, including the Palomar, Cuyamaca and I
Mountains, which constitute a formidable barrier between the broad chaparral belt to the we
the arid lowlands of the Colorado Desert to the east. The mountains reach peak elevations (
6,000 feet above sea level (1,850 m) before dropping sharply to near sea-level in the Anza-B
Desert. The mountainous areas support chaparral, oak woodland, montane coniferous forest,
evergreen forest, and riparian woodlands. The desert is topographically diverse, extending frc
eastern slopes of the mountains to far beyond the eastern border of the county. This re
vegetationally diverse as well, supporting chaparral, pinyon-juniper woodland, creosote bush
alkaline sink, dune, playa, and riparian habitats.
I
I
I
1
I
I 1.23 CLIMATE
I
I
I
1
I
1
I
I
I
I
I
I
I
Based on average temperature and precipitation, San Diego County includes faur natural c
zones (Pryde 1984): (1) cool Mediterranean, (2) warm Mediterranean, (3) semiarid (or stepp
(4) arid (or desert). All of these climatic zones are characterized by cool, moist winters and 1
summers. Within these four types, topographic features and proximity to the ocean coml
create a diversity of specific micro-climatic regimes within the county. Along the narrow coast,
fog constitutes a major source of water for many native plants. Average precipitation along th
ranges between 10 and 12 inches (25-30 cm) per year. Proximity to the ocean helps m
relatively constant temperatures. The lowland mesas (also known as marine terraces) are
warmer than the immediate coast and receive slightly more precipitation -- 12 to 115 inches (30.
per year. Above about 1,300 feet (400 m) elevation, the mountainous areas receive consic
more precipitation than the coastal and mesa areas to the west, and the vegetation is tal
denser. Above about 3,900 feet (1,200 m) elevation, temperature and precipitation regimes I
coniferous forests. Winter snow is infrequent but regular in the higher elevation,s of the mol
The rain-shadow effect of the mountains on lands further east, inhibiting moisture-laiden clouc
reaching further inland, is manifested in dry, desert conditions that prevail throiighout most
year. Desert temperatures are extremely variable; summer temperatures typically exceed 100 (
Fahrenheit (38 degrees Celsius) in the lower valleys.
1.2.4 GEOLOGY AND SOILS
San Diego County is divisible into two large geomorphic provinces on the basis of surface 1
and relief (Pryde 1984). The Coastal Province occupies the western portion of the
corresponding to the region of sedimentary surface rocks. The dominant relief of this provi
series of marine terraces also known as mesas. The Peninsular Range Province comprises the
of the county located east of the Coastal Province and is composed of plutonic and metal
surface rocks. The major relief elements of this province include the general northwest-sc
trending foothills and mountain ranges, the highest peaks, and the steep eastern slopes
mountains.
According to Bowman (1973), 53 different soil series are present in San Diego County, ir
sandy, cobbly, loamy, and clayey, and soils associated with gabbro parent material and Santial
metavolcanic formations. A soil series is a group of closely related soils that shares similar
of surface, slope, stoniness, and other characteristics that affect use of the sod by man.
coastal terraces most of the soil series are comprised of sandy loams, clay loam:;, and clays.
foothills on the western slopes of the mountains, the soils generally are well-drained sandy le
3
silt loams overlaying decomposed granitic or metavolcanic rock. The mountainous areas are
characterized by well-drained sandy loams over granitic bedrock In the desert, soils range from
virtually none on the steeper slopes, to coarse sandy alluvial soils on the gentler slopes. Soil diversity
acts to promote botanical diversity: many endemic plant species are confined to a single or a few soil
types (Oberbauer 1991a).
1.2.5 PLANT COMMUNITIES
A plant community is an association of plant species that is readily recognizable in the field. Plant
communities are thought to reflect particular biogeographic and ecological conditions. Plant
communities are recognized by their "dominant" species, which tend to occur together.
Plant communities are closely related to climatic zones, available moisture, slope aspect (exposure),
soil type, and disturbance. For some communities, such as coastal sage scrub, chaparral, and southern
interior cypress forest, fire plays an integral role in community succession and is necessary to maintain
the integrity and productivity of the habitat (Zedler 1977). For other communities, perturbations may
have very long-lasting dramatic effects. Plant communities are the major determinants of wildlife
diversity and abundance, and they play a vital role in determining species distributions. The major
plant communities present in San Diego County are discussed briefly below (see Table 1)-
Terminology in the table is after Oberbauer (199lb) while the terminology in the text follows Holland
( 1986).
Plant communities present along the coastal strand include a number of dune communities (Le-, active
coastal dunes, southern foredunes, and southern dune scrub). The plants of these communities
typically are small herbaceous or succulent species, often with a prostrate growth habit. They cover
the surface sparsely, leaving areas of bare sand. The general aspect of this community is determined
by nearly constant onshore breezes, fine sandy soils, and moderately saline conditions. Among the
most common species in this habitat type are sea-rocket (Cakile marifha), beach evening-primrose
(Camissonia cheirantbifolia), beach bur (Ambrosia chamis:Fonis), and sea-fig (Calpobrotus spp.).
Coastal strand vegetation has been replaced in most areas by recreational or urban development, and
elsewhere it has been degraded by frequent human disturbance. Dune communities are best
preserved at Border Field and Silver Strand State Parks. In all other coastal areas throughout the
county, coastal strand or dune communities are extremely limited.
Wetland communities found along the coastal strand include southern coastal salt marsh, coastal
brackish marsh, and coastal and valley freshwater marsh. In these aquatic and semi-aquatic habitats,
plant species composition varies considerably, depending upon duration of inundation, tidal flow or
runoff, and salinity. Salt marshes are characterized by low-growing succulents such as pickleweed
(Salicomia spp.), salty Susan (Jaumea camosa), salt grass (Disfichlk spicata), salt-cedar (Monanthochloe littoralis), and other halophytic (salt-tolerant) species. Some salt marsh systems
include an outer marsh characterized by stands of tall cordgrass (Sparha folkxa). Salt marsh
communities are highly productive systems and function as hatcheries for many species of fish, and
provide food and refuge resources for a variety of locally resident and migratory water birds. Salt
marsh habitat is best developed at places like Tijuana Estuarine National Wildlife Refuge, the mouth
of the Sweetwater River, and the mouth of the Santa Margarita River. Freshwater marshes typically
are dominated by cattails (Typha spp.), bulrushes (Scirpus spp), and dock (Rumex spp.). Patches of
this habitat are present at the upper ends of Buena Vista, Agua Hedionda, Batiquitos, and San Elijo
lagoons, where a mixture of plants of salt and freshwater habitats is encountered. Smaller freshwater
marshes grow around the perimeter of many lakes and ponds on the coastal slope.
4
TABLE 1 I
I
I
I
I
I
I
I
II
I
I
I
I
I
1
1
I
D
I
COMPARISON OF PRE-EUROPEAN AND 1988 VEGETATION COTJERAGE
FOR SAN DIEGO COUNTY
(AFTER OBERBAUER 1991d)
Directic
Original Ac. Current Ac. Change Q) of Chal
Chamise Chaparraf 599,820 466,947 22% Reduct Creosote Bush Scrub 532,290 500,220 6%) Reduct Mixed Chaparraf 500,540 467,715 7% Reduct Coastal Sage Scrub273 480,260 135,370 72% Reduct Desert Transition 143,680 143,680 0% NO Chi Native Grassland 125,680 7,250 94%) Reduct
Oak Woodland (sparse) 80,500 78,540 2% Reduct
Riparian Woodland 34,580 13,570 61% Reduct
Oak Woodland (dense)* 3,9Oo 27,140 6% Reduct Desert Wash 21,040 21,040 0%) NO Chz Coastal Mixed Chaparraf 20,620 2,530 88% Reduct
Mountain Meadow 16,480 16,480 0% NoChz
Juniper Woodland 12,230 12,230 0% NoChz
Pinon Woodland 8,190 8,190 0% NoChz
Coastal Salt Marsh' 6,530 810 68% Reduct
Creosote Bush-Wash Complex 5,040 5,040 0% NoChz Mesquite Bosque 4,610 4,209 9% Reduct Cypress Woodland 4,440 4,229 5% Reduct Coastal Strand2 1,940 0 100% Essentia
Dry Lake-sink 1,580 1,580 0% NoChe
Freshwater Marsh' 19090 100 91% Reduct,
Torrey Pine Woodland 310 250 19% Reduct
Agriculture-Urban complex4 0 339,030 100% NewTq
Disturbed Grassland4 0 203,760 100% NewTq
Agriculture4 0 159,640 100% NewTq
Lakes/Reservoirs4 0 10,800 100% NewTq
Total 2,709,360 2,709,360
1 = After: Oberbauer, T.A. 1991. In: Abbott, P. and B. Elliot. Geol. SOC. North Amc
Calif. Reg., Sympos. 0ct.-21-24, 1991, San Diego, California. Does not follow Holland
precisely. * = Occurs in Carlsbad
3 = Oberbauer splits coastal sage scrub into two components: inland sage scrub and m
sage scrub. Inland sage scrub has been reduced from 428,480 acres to 13 1,OOO acres 1
reduction). Maritime sage scrub has been reduced from 51,780 acres to 4,370 acres (
reduction).
4 = Man made
Coniferous Forest 79,010 79,010 0%) NO Chl
5
Terrestrial upland vegetation closest to the coast includes Diegan coastal sage scrub, southern coastal
bluff scrub, maritime succulent scrub, southern maritime cha!parral, and Torrey pine forest. Diegan
coastal sage scrub consists primarily of aromatic shrubs and sub-shrubs with an understory of annual
herbs and perennial grasses. Characteristic species include coastal sagebrush (Artemisia califopnia),
California buckwheat (Eriogonum fasciculatum), white sage (Salvia apiana), lemonadeberry (Rhus
integrifolia), laurel sumac (Malosma laun'na), and purple needlegrass (Stipa pzclchra). Typical coastal
sage scrub occurs in many places, including the hills around Poway, the Dulzura-Jamul area, south
of Lake Hodges, and portions of Camp Pendleton. Southern coastal bluff and maritime succulent
scrub include a variety of succulents and cacti, such as velvet cactus (Bergerocactus emoryi), fish-hook
cactus (MammiZZarira dzbica), coast cholla (Opuntia prolifepa), San Diego barrel cactus (Ferocactus
viridescens), prickly-pear cactus (Opuntia littoralis), cliff-spurge (Euphorbia mrkera), bladder-pod
(Cleome isomeris), and several species of dudleya (DdZeya spp.), mixed with typical sage scrub
species. This community type is well developed at Torrey Pines State Park, Tijuana Hills above
Border Field State Park, and Cabrillo National Monument. Southern maritime chaparral is limited
to the area between Mount Soledad and southern Carlsbad. It is a community characterized by
several endemic shrubs, usually growing on sandstone: Del Mar Manzanita (Arctostaphylos glundulosa
var. crassifoh), wart-stemmed ceanothus (Ceanothus vemicosus), coast spice bush (Cneoridium
dumosum), mission manzanita (Xyllococcus bicolor), and Del Mar mesa sand-aster (Corethrogyne
flaginifolia var. linifolia). Torrey pine forest is an exceedingly restricted community known only from
the vicinity of Del Mar and Torrey Pines State Reserve in San Diego County. It is an open-to-
moderately dense forest dominated by Torrey pine (Pinus ton-eyana), with an extremely variable
understory.
Scattered on flat-topped mesas, marine terraces, and some valleys is a unique habitat that is,
unfortunately, one of the most depleted habitat types in San Diego County -- vernal pools (San Diego
Mesa hardpan vernal pool and Otay Mesa claypan vernal pool). These small shallow pools develop
in "mima mound" topography where an underlying semi-impermeable hardpan layer intercepts winter
rainfall and creates a perched water table. Vernal pools support a unique and ephemeral aquatic and
semi-aquatic biota, quite distinct from the adjacent chaparral or grassland, that includes several plant
species recognized as rare, threatened, or endangered by local, regional, and national conservation
agencies, including San Diego mesa mint (Pogogyne nbramsii)., Otay mesa mint (Pogogyne nudiuscula),
San Diego button-celery (Eryngium aristulatum var. parishii], California Orcutt grass (Orcunin
cal~omica), and San Diego navarretia (Navarretia fossalis). Vernal pools are found in several areas
of the county, including Otay Mesa, Kearny Mesa, Dei Mair Mesa, Clairemont Mesa, San Marcos,
Ramona, and Fletcher Hills (Bauder 1986).
Inland from the coast, chaparral is the dominant plant community, covering about 35 percent of the
county's land surface. Although several types of chaparral are recognized by Holland (1986) (Le.,
southern mixed chaparral, chamise chaparral, scrub oak chaparral, mixed montane chaparral, mesic
north slope chaparral, and southern north slope chaparral), all are composed of tall shrubs with hard
evergreen leaves and stiff woody stems. Plant species composition varies from region to region within
the county, but dominant species usually include chamise (Adenostoma fasciculatum), manzanitas
(Arctostaphylos spp. and Xyloccocus bicolor), wild-lilac 1: Ceanothus spp.), toyon (Heteromeles
arbutifolia), mountain-mahogany (Cercocarpus spp.), Spanish bayonet (Yucca whipplez?, and interior
scrub oak (Quercus berbe&!$olhz). Fire plays an integral role in the succession of chaparral
communities, and many of the resident plant species are highly adapted for vigorous vegetative
reproduction (crown- and stump-sprouting) following fires.
Occurring throughout the coastal area and into the foothills and mountains are several types of
natural grasslands that often are associated with clayey soils. Coastal perennial grasslands may range
in size from patches within sage scrub or chaparral that are less than 100 square feet to (rarely) 20
to 100 acres. They often are dominated by purple needlegrass, a number of non-native grasses (Le.,
6
Avena spp., Bromus spp., Gastridium ventricosum, Vulpia spp.), sanicles (Sanicur'a spp.), blu
grass (Skyrimhiurn bellum), and gum-plant (Grindelia robusta).
Riparian woodlands (Le., southern coast live oak riparian forest, southern arroyo willow ri
forest, southern cottonwood-willow riparian forest, and southern willow scrub) cover less tk
percent of the county's area. Although small in acreage, these woodlands suipport the I
diversity and greatest abundance of wildlife species of any community type; riparian woodlar
noted for their rich diversity of breeding bird species (Unitt 1984). Riparian habitats play a vi1
in nutrient recycling and in water quality maintenance. Along large, perennial river cours
smaller, seasonally moist drainages, the woodlands are comprised of willows (Sdix spp.), FI
cottonwood (PopuZus@ernonri& and western sycamore (Platanus racemosa), with a tangled undl
of poison-oak (Toxicodendron diversilobum), desert grape (fitis girdiana), and a variety of
hydrophytic (wetland) species. Canyon bottoms that do not have enough water to support t
complement of riparian vegetation often contain sycamores. In drier canyon bottom, on north
slopes, and along the edges of valleys, dense groves of coast live oak (Quercus ap~olia) form a
canopy oak woodland. Another type of oak woodland occurs in some parts of the foothill
where widely spaced individuals of the endemic Engelmann oak (Quercus engelmanniz) form a
woodland or oak savannah.
Coniferous woodland communities (Jeffrey pine forest, western ponderosa pine forest, and (
pine forest) are restricted to montane habitats and some isolated peaks that receive over ab
inches (46 cm) of rain per year. Pines (Pinus spp.) are the dominant plants of this communi
canyon live oak (Quercus chrysulepk), black oak (Quercus keZlog@z), and wild-lilac (Ceanothu
also are important components. The composition and character of this community vary with hi
and exposure. In drier, flatter areas, the trees are more widely spaced, there is little ground
and Jeffrey (Pinus jefjeyi) and Coulter pines (Pinus coulten] dominate. In more humid area
as Cuyamaca Mountain, Palomar Mountain, or on steep north-facing slopes, conifers arc
diverse, and the flora includes incense-cedar (Calocedrus decurrens), white fir (Abies concolo
cone Douglas-fir (Pseudotsuga macrocaFa) and sugar pine (Pinus lambertiana).
Scrub vegetation covers most of the desert edge at the steep eastern escarpment of the mo
between about 2,500 and 4,000 feet (760-1,220 m). This area includes elements of chapar
creosote bush scrub (described below), as well as plant species found sparingly in other art
county. The most prominent of these are California juniper (Juniperus califomica), turpentine
(Thamnosma montana), and desert apricot (Prunus fremontig.
Most of the lower desert area is covered by a sparse scrub community known as Sonoran c:
bush scrub. Creosote bush (Larrea tridentata) is the dominant shrub, but the density of p
much lower than that found in other vegetational communities. Sub-dominants in this habitat
ocotillo (Fouqueria spledem), brittlebush (Encelia farinosa), barrel cactus (Ferocactus acant
and burrobush (Ambrosia dumosa). Other communities found in this drier easiern portion
county include active desert dune, Sonoran mixed woody and succulent scrub, desert grea scrub, desert dry wash woodland, and peninsular juniper woodland and scrub. Although (
desolate during most of the year, the desert areas usually come to life in the spring following
winter rainfall. Wildflower displays may be magnificent during this brief flowering season.
1
I
I
I
i.
1
I
I
1
I
1
1
I
I
I
I
I
I
I 1.2.6 SENSITIVE BIOTA
Southern California has a long history of human use and consequent alteration of the ecosysti
it has experienced rapid urban expansion and habitat change over the past three or four decac
Diego County has not been immune. Although habitat degradation has occurred throughoL
of the county, the coastal areas have been altered the most severely. As well as providing prir
7
for housing and other development, these areas have been disrupted by the abuses of recreation and
off-road vehicles. According to the City of San Diego (Hix 1990), the native coastal strand
community has been eliminated nearly entirely; coastal salt marsh has been reduced by greater than
87 percent; coastal sage scrub has lost over 70 percent of its previous acreage; vernal pool habitats
have been reduced by 96 percent; and coastal mixed chaparral has declined by more than 87 percent
in §an Diego (see Table 1). The net overall result of this considerable loss in native habitat is the
concurrent decrease in native wildlife and plant species. (See Appendix A for lists of wildlife and
plant species in Sari Diego County with federal and state sensitive species designations.)
Several species of birds associated with disappearing habitat types and/or habitat degradation are
recognized as threatened or endangered by state or federal agencies: California brown pelican
(Pelecanus occidentalis), light-footed clapper rail (Rallus longirostrk levipes), Belding’s Savannah
sparrow (Ammodra,mus sandwichensis beldingi], and California least tern (Stema antillarum browni),
all associated with coastal estuaries and salt marsh habitats; and least BelR’s vireo (Vireo belliipusillus),
restricted to riparian woodlands. Also receiving much attenriion is the federal proposed endangered
California gnatcatcher (Polwptila califomica), occurring primarily in coastal sage scrub communities
below about 1,200 feet (370 m). Other species recognized as sensitive include coastal cactus wren
(Campylorhynchus brunneicapihs sandkgensis), sage sparroiw (Aimophila belli), Southern California
rufous-crowned sparrow (Aimophila ruficeps canescens), California homed lark (Eremophila aIpestris
actia), and several species of raptors (birds of prey).
Mammal species occurring in San Diego County listed as threatened or endangered by the U.S. Fish
and WiIdIife Service (USFWS) or the California Department of Fish and Game (CDFG) include
Stephens’ kangaroo rat (Dipodomys stephensz], found in the northwestern portion of the county and
on Camp Pendleton; and peninsular bighorn sheep (&is canadensis cremnobates), an inhabitant of
the rugged hills in the desert portion of the county. The ringtail (Bassarixus astutus), a state fully
protected species, occurs in riparian, scrub, and forest habitats in the county. The CDFG recognizes
20 species of mammals that occur within San Diego County as “Species of Special Concern,” including
eight species of bats. Species that are both federal Category 2 candidates and on the state list of
sensitive species include the Pacific pocket mouse (Perognathus longimembris pacificus), the Los
Angeles pocket mouse (Perognathus 1ongimembti.s brevinasus), and four bats. In addition, there are
several new federal Category 2 candidates that are not yet designated by the State as sensitive species
(see Appendix A).
Reptiles that are recognized as federal Category 1 or 2 candidates for listing as endangered by the
USF’WS or as Species of Special Concern by CDFG include the San Diego horned lizard
(Phymosoma coronamm blainvillei), orange-throated whiptail (Cnemidophorus hypeiythms beldingi),
northern red-diamond rattlesnake (Crotalus ruber), coastal whiptail (Cnemidophorus ti@
multiscutatus), barefoot banded gecko (Coleonyx switaki). and San Diego mountain kingsnake
(Lampropeltis zonaita pulchra). Sensitive or declining amphibians include western spade-foot toad
(Scaphwpus hammondi), reg-legged frog (Rana aurorci draytoni), and arroyo toad (Bufo
[microscaphus califomicus] califomicus).
Seven species of butterflies indigenous to San Diego &unty are recognized as federal Category 2
candidates for listing as threatened and endangered, namely the Laguna Mountains skipper (Pyrgus
ruralis lagunae), wandering skipper (Pseudocopaeodes eunus). Harbison’s dun skipper (Euphyes vestris
harbisoni), salt marsh skipper (Panoquina emans), Hermes copper (Lycaena hermes), Thorne’s
hairstreak (Mitoura thomei), and quino checkerspot (Euphydiyas editha quino). The USFWS has
been petitioned to list several of these species as endangered. Also, the globose dune beetle (CoeZus
globosus), a resident of coastal dunes, is a federal Category 2 candidate species, and two other
invertebrates -- the Riverside fairy shrimp (Streptocephalus woottonii) and San Diego fairy shrimp
(Branchinecta sandiegoensis) have been proposed or petitioned to be listed as endangered.
8
San Diego County exhibits an exceptionally high degree of floral endemism -- it contains nurr
plant species that are found nowhere else. With 173 species recognized as sensitive by the Cali
Native Plant Society (Smith and Berg 1988), San Diego County is second only to San Bern:
County in this regard. Plant species of San Diego County listed as threatened or endangered 1
USFWS include salt marsh bird’s-beak (Cordylanthus maritimus), restricted to coastal salt ma
and San Diego mesa mint (Pogogyne abramsii), an inhabitant of San Diego Mesa hardpan 3
pools. State-listed rare, threatened, or endangered plant species include the two listed abovc
San Diego thornmint (Acanthomintha ilicifoh), coastal dunes milk vetch (Astrugtzlus tener va
Encinitas baccharis (Baccharis vanessae), Dunn’s mariposa lily (Calochortus dunni), San Diego b
celery (Elmgiurn ari.stulatum var. parishii), and many others. The USFWS recognizes 76 spec
local plants as federal Category 1 or 2 candidates, and they have proposed three species for
as endangered: Otay mesa mint, San Diego button-celery and California Orcutt grass.
San Diego County also supports a variety of sensitive habitats. A sensitive habitat is define
vegetation community type that has been significantly depleted due to development and has
identified as warranting protection by the CDFG (e.g., coastal sage scrub, coastal1 strand, or c
salt marsh), uncommon within a region, but common elsewhere (e.g., Jeffrey pine forest is limi
San Diego County), as habitat that supports rare, endangered, or threatened plant or animal SI
or areas that are needed to maintain a btilanced ecosystem or wildlife corridor (City of San
1991). Sensitive habitats in San Diego County relevant to the City of Carlsbad i3nd this doc
are coastal sage scrub (including all subassociations), southern maritime chaparral, oak WOC
riparian scrub, freshwater marsh, salt marsh, open water, and native grassland.
1.3 SUMMARY AND CONCLUSIONS
Because of its highly varied topography, soils, and climatic conditions, San Diego County suppc
exceedingly diverse biota. Numerous plant communities are present within the county boun
each of which supports its own distinctive assemblage of plant and wildlife species.
Urban growth throughout San Diego County has had a tremendous effect on the local biota.
plant and animal species have become increasingly rare throughout the region and some have b
locally extinct. Projected land development and human population growth in the region will in
the pressure on a large number of habitats and species that are literally now on the br
extinction. Although sensitive species are designated as threatened, endangered, rare, declin
depleted by local or regional conservation agencies, sensitive habitats are not provided wit
designations. The most depleted habitat types include coastal dunes, coastal salt marsh, m:
succulent scrub, coastal sage scrub, native grassland, riparian woodland, and venial pool. TI
of natural habitat results in the decline of native plant and wildlife species.
San Diego County is one of the most desirable places in the country to live. In order for the
to continue to offer a high quality of human life, severe challenges in natural resource manal
must be met, including preservation of open space, maintenance of water and air quality,
management, control of noise pollution, and preservation of our natural heritage. Concurren
economic vitality of the region must be maintained and enhanced for the present and the fu
To achieve these objectives, it is vital to design and implement development alternatives t
compatible with the preservation of biological resources. Habitat management plans, such
under development by Carlsbad, and similar plans being undertaken by government and indil
provide a means for attaining this goal.
I
1
1
I
1
1
I
1
1
I
I
I
1
8
1
1
1
I
I
9
,
, /
\
/
BIOLOGICAL &SOURCES AND !.%BITAT ANALYSIS
in support ofthe CITY OF CARLsBAD HABITAT MANAGEMINT PLAN
,
SECTION 2
CITY OF CARLSBAD
THE LOCAL SETTING
I
I
I
I
R
I
I
I
I
I
I
I
I
1
I
I
I
I
2.1 INTRODUCTION
The City of Carlsbad is situated along the Pacific coast of California, in northwestern San
County, approximately 30 miles (45 km) north of the City of San Diego. It is bordered on the
by the City of Oceanside, on the northeast by the City of Vista, on the east by the City c
Marcos, on the south by the City of Encinitas, and on the west by the Pacific Owan (Figure
extends about 4.5 miles (6 km) from east to west and about 7.0 miles (9 km) from north to so
covers approximately 40 square miles (about 24,000 acres or 15.44 square Km). Elevations
from sea level along the coast to about 960 feet (280 m) at the highest point at the southe I border of the City.
The City of Carlsbad has been a valuable agricultural area since prior to the 20th century, ar
experienced significant urban expansion over the past three or four decades. The human pop1
of the City is estimated to be approximately 63,000. Urban development for housing and othc
has resulted in degradation and outright loss of significant blocks of native habitat. EncamF
of migrant workers and homeless people also have degraded much habitat, particularly in ri
areas. Native communities associated with the coastal areas have been disrupted by the abt
active recreation and off-road vehicles.
Although much of the City has been subject to agriculture, housing, commercial developme
other uses, open space areas within Carlsbad support a diverse biota and a variety of sensitivc
and wildlife species. Over 300 species of plants, 200 species of birds, 25 species of reptil,
amphibians, 20 species of mammals, 44 species of fish, 45 species of butterflies, and several thc
species of terrestrial and aquatic invertebrates retain populations within the City. 1 nformation
status of many of these populations, however, is lacking, and it is not known whelher the ren
populations of these species are viable.
As with much of San Diego County, the City of Carlsbad has experienced significant urban
in recent years. The entire City lies within 4.5 miles of the coast; hence human population eq
and habitat change is concentrated within the coastal area where many sensitive and
diminishing biological resources occur. Consequently, conflicts between urban growth a
maintenance of biological diversity are encountered frequently. These factors make conse
planning in these areas particularly challenging.
2.2 EXISTING CONDITIONS
2.2.1
The western edge of the City, lying along the Pacific coast, is characterized by sandy beacl
three low-lying river estuaries or lagoons -- Batiquitos Lagoon, Agua Hedionda Lagoon, and
Vista Lagoon. Buena Vista Lagoon, at the northern border of the City, is fed by 13uena Vista
a local drainage that forms much of the border between the cities of Oceanside and Carlsbz
watershed of Agua Hedionda Lagoon includes a drainage that extends from Lake Calaver
northeastern comer of Carlsbad. Batiquitos Lagoon lies along the southern boundary of the (
extends inland from the coast to near El Camino Real, where it receives runoff from slope:
north side of the lagoon and a drainage from the south. The lagoons dominate the coastal la
GENERAL TOPOGRAPHY AND LANDSCAPE FEATURES
10
Oceanside
7" = 65C r! Carlsbad Habitat Management Plan
Vicinity Map
of Carlsbad and provide habitat for a variety of resident and migratory bird species. Wit
exception of some habitat that immediately borders the estuaries, native communities o
immediate coast either have been degraded severely by human activities or have been lost alto!
to development. Inland from the coast is a series of low coastal mesas and rolling foc
supporting shrublands, grasslands, and agriculture, with intervening ravines and canyons supp
narrow oak woodland, riparian scrub, coastal sage scrub, and chaparral communities. Two freshwater bodies occur within Carlsbad near the eastern edge of the City -- Lake Calaver
Squires Dam. Both support adjacent freshwater marsh and riparian woodlands. A deep, roughl:
west trending gorge dominates the landscape locally in the southeastern portion oE the City th
the Fieldstone Company-owned lands east of La Costa.
Agriculture (including tomatoes, flowers, and others) is a dominant feature of the land
particularly in the area north of Palomar Airport Road east of Paseo del Norte, and south of Pa
Airport Road east of El Camino Real. Private golf courses also occupy considerable areas of
space, including courses associated with the La Costa and Aviara developments. Golf cc
typically occupy lower, more level bottomland areas between steep or sloping terrain.
2.2.2 CLIMATE
Based on average temperature and precipitation, the City of Carlsbad lies entirely within the se
(or steppe) climatic zone (Pryde 1984). Average annual precipitation is 10.7 inches. Average 4
temperature is 59.2 degrees Fahrenheit (F'); average July/August high temperature is 72.9 degi
and average January low temperature is 42.6 degrees F. Temperatures typically exhibit g
differences furthest from the coast. Highly seasonal rainfall generally occurs between Octob
April; coastal fog is common in May and June.
2.23 GEOLOGY AND SOILS
The City of Carlsbad lies entirely within the Coastal Geomorphic Province, which occupi
western portion of San Diego County corresponding to the region of sedimentary surface rock
dominant relief of this province is a series of marine terraces also known as mesas.
According to Bowman (1973), 33 different soil series are present in the City of Carlsbad, inc
sandy, cobbly, loamy, and clayey types, and soils associated with gabbro parent ma1.erial and Sa
Peak metavolcanic formations. On the coastal terraces most of the soil series are comprised oi
loams, clay loams, and clays. In the foothills the soils generally are well-drained ,sandy loams
loams overlaying decomposed granitic or metavolcanic rock.
2.2.4 PLANT COMMUNITIES
Eight distinct native plant communities (Holland 1986) are present within the Ciiy of CarIsb;
Section 3 for details of mapping). In addition, three non-native habitat types @e., euc
woodland, disturbed wetland or floodplain, and disturbed habitat), open water, and developme
account for significant areas within Carlsbad (see Section 3 for discussion). These native an
native habitat types are discussed below with respect to their general habitat structure,
composition, and general location within the City of Carisbad. Terminology andl definitions
natural communities follow Holland (1986), for the most part, with modifications to confor
community types recognized by Ogden Environmental and Energy Services (in [heir Multi-
Conservation Plan [MSCP] mapping efforts) and SANDAG (Table 2).
i
I
8
I.
I
1
I
I
1
I
I
1
1
I
I
I
1
I
I
11
TABLE 2
CLASSIFICATION SYSTEM FOR HABITAT COMMUNITIES
OCCURRING IN THE CITY OF CARLSBAD
SANDAG Holland
Habitat Type Code Code
Coastal Sage Scrubs
coastal sage scrub 30 32000
disturbed coastal sage scrub 31 32001
maritime succulent scrub 40 32400
southern mixed chaparral 52 37120
chamise chaparral 53 37200
southern maritime chaparral 60 37630
coastal sage scrubkhaparral 70 37G
non-native (annual) grassland 82 42200
native (perennial) grassland 83 42100
Saltwater Marsh 90 52100
Freshwater Marsh 100 52400
Sycamore Alluvial Woodland 123 62400
Riparian Scrub 130 63000
Oak Woodland 140 71 100
Chaparrals
Grasslands
Eucalyptus Woodland 190
Open Water 200
Disturbed Wetland 210
Disturbed Habitat 240
Active Disturbance 242
Active Agriculture 243
Golf Course 244
Developed 250
Source: MSCP Habitat Type (modified from Holland 19436).
Coastal Sage Scrub
Within the City of Carlsbad, coastal sage scrub is represented by Diegan coastal sage scrub and
maritime succulent scrub, as well as disturbed forms of both types. Diegan coastal sage scrub is a
droughtdeciduous community comprised of aromatic shrubs and subshrubs with a diverse understory
of annual and perennial herbs, perennial and annual grasses and grass-like plants. Diegan coastal
sage scrub occurs primarily on dry south-facing slopes and hillsides or on clay-rich soils adjacent to
chaparral or upslope from riparian woodlands. Character istic species include coastal sagebrush,
California buckwheat, black sage (Salvia mdlifera), white sage, lemonadeberry, laurel sumac, and
purple needlegrass. It also supports a variety of sensitive plant species, including California adolphia
(Adolphia califomica), ashy spike-moss (Selaginella czherascms), San Diego sand-aster, and several
others. Sensitive wildlife species that occur primarily in coastal sage scrub include San Diego horned
lizard, orange-throated whiptail, California gnatcatcher, and coastal cactus wren. Coastal sage scrub
12
frequently occurs in a mosaic distribution with native grasslands and occasionally with chaparra
largest remaining tracts of Diegan coastal sage scrub are found in the vicinity of Lake Cal
southeast of Agua Hedionda Lagoon, and near Rancho Santa Fe Road. Maritime succulent includes a variety of succulents, such as fish-hook cactus, coast cholla, California desert thorn (L
cdifomicum), cliff-spurge, bladder-pod, and several species of dudleya (Dudleya spp.), mixec
typical Diegan sage scrub species. This community type is found along the remaining narrow L
borders of the lagoons and on some west-facing slopes near the coast.
Cha~arral
Three types of chaparral are recognized within the City: southern mixed chaparral, southern ma
chaparral, and chamise chaparral. Southern mixed chaparral is a fire- and drought-ac
community composed of a variety of woody shrubs, many of which are ''stump sprouters
regenerate rapidly from underground undamaged tissues following fires or other ecol
perturbation. It is a heterogeneous community type -- the dominant shrubs vary from site t In most situations the dominants include chamise, interior scrub oak, mission manzanita, laurel s
lemonadeberry, and toyon. Understory plants include rush-rose (HeZianthemum scqpariurn), dee
(Lotus scoparius), wreathplant (Stephanomeria spp.), and a variety of composites (Astera
Southern maritime chaparral is similar to southern mixed chaparral, but it occuf?;; on sandstc
is the most limited chaparral type in distribution, particularly in Carlsbad, and is characten
several endemic shrubs, including Del Mar Manzanita, wart-stemmed ceanothus, coast spice bu:
coastal scrub oak (Quercus dumosa). Other dominant shrubs encountered in this community i
same as those listed above for southern mixed chaparral. Sensitive plant species encounte
southern maritime chaparral include wart-stemmed ceanothus, summer-holly ( Comarostl
diversifoh var. diversqoolia), Del Mar manzanita, ashy spike-moss, and western dichondra (Dic!
occidentah). Chamise chaparral is a community where chamise is the overwhelming dominant This species may account for over 90 percent of the relative cover. The remaining species i
shrubs and understory plants common in other types of chaparral.
Chaparral has a patchy distribution throughout the City of Carlsbad, occurring on more mesic
and west-facing slopes, alternating with coastal sage scrub, grasslands, and oak woodlands. The
and most representative patches occur immediately east of the Safety Center, southwest of 5
Dam, at the north end of Rancho Santa Fe Road, and along El Camino Real south of P;
Airport Road.
Grassland
Both native (perennial) and non-native (annual) grasslands are present within thle City of CP
Native grasslands usually are small in area, frequently occurring as difficult-to-define, open I
of habitat within coastal sage scrub. Many are associated with clayey soils. Native grasslai
characterized by perennial bunch grasses such as needlegrass (Stipa spp.), and a variety of herb
annuals and perennials such as Cleveland's shooting star (Dodecatheon clevelandii], blue-eyec
fascicled tarweed (Hemizonia fasckuZatum), sanicles, and mariposa lily (Calochortus spp.)
habitat type is extremely limited in quantity within the City of Carlsbad, although small patc
distributed throughout many areas of native vegetation. Non-native grasslands occur where
communities have been degraded by repeated fire, grazing or mechanical disturbance, in
agriculture. These areas are dominated by a number of non-native grasses, including wild oats
spp.), bromes (Bromus spp.), and others (e-g., Gastridium ventricosurn, Vdpia spp.); native
are few. Other species present in non-native grasslands include invasive natives such as tel
weed (Heterotheca grandiflora), fascicled tarweed, doveweed (Eremocalpus setigems), and
introduced species such as Russian-thistle (SalsoZa austrah), black mustard (Brassica nig
I
D
I
I
I
1
1
8
I
1
1
I
I
1
t
I
I
I
I
13
tocalote (Centaurea melitensis). Non-native grasslands are: best represented in the southeastern
corner of the City and south of Palomar Airport Road at the eastern edge of the City.
Southern Coastal Salt Marsh
Southern coastal salt marsh is a wetland community that develops in low, flat estuaries at the mouths
of rivers and streams. Tidal inundation or excessive evaporation results in highly saline conditions
around the margins of lagoons, and it is under these conditions that salt marshes develop. This
community is characterized by low-growing succulents such as pickleweed, salty Susan, salt-cedar, and
other halophytic (salt-tolerant) species. Salt marsh commuriities are highly productive systems that
function as nurseries for many species of fsh and provide resources for a variety of locally resident
and migratory water birds. This community supports a variety of sensitive birds, including Belding’s
Savannah sparrow, light-footed clapper rail, and California least tern. It also supports one sensitive
invertebrate -- the salt marsh skipper. Within the City of Carlsbad, salt marsh habitat is present
surrounding Batiquitos Lagoon and Agua Hedionda Lagoon, although Batiquitos Lagoon is not open
to the ocean. It also occurs in limited amounts around Bue:na Vista Lagoon and possibly at Loma
Aha Creek. Several researchers have described distinct zones within southern coastal salt marsh (e.g.,
Zedler 1982).
Coast and Vallev Freshwater Marsh
Freshwater marsh occurs in drainages, seepages, and other perennially moist low places. This
community is characterized by perennial, emergent monocots (e.g., grasses and lilies), 2-3 m (6-10
feet) tall, such as cattails and bulrushes. Understory species include curly dock, marsh fleabane
(Plucheu atoruta), and a variety of hydrophytic grasses and herbs. Sensitive plants frequently
encountered in the vicinity of this community are spiny rush (Juncus acutus var. sphaerocarpus) and
San Diego marsh-eider (Iva hayesiana). Patches of this halbitat are present at the upper ends of
Buena Vista, Agua Redionda, and Batiquitos lagoons, where a mixture of plants of salt and
freshwater habitats is encountered. Smaller freshwater marshes grow around the perimeter of Lake
Calavera and within riparian scrub communities, and may be: present in Loma Alta Creek.
Svcamore Alluvial Woodland
Sycamore alluvial woodland is an open to moderately closed, winter-deciduous, broadleafed riparian
woodland, dominated by well-spaced western sycamore. The community typically includes individuals
of several other tree species, including willow, coast live: oak, Mexican elderberry (Sambucus
mexicam), and Fremont cottonwood. This community is best developed in broad channels of
intermittent streams, usually with a cobbly substrate. Sycamore alluvial woodland is uncommon in
Carlsbad, occurring primarily in the drainage east of the Safety Center and along a narrow drainage
south of Lake Calavera.
RiDarian Scrub
As used herein, the term riparian scrub encompasses several natural and semi-disturbed wetland
communities, including mulefat scrub, southern willow scrub, and baccharishamarisk scrub. These
communities occur along river courses and seasonally moist drainages. In Carbbad, some riparian
scrub communities are the result of urban or agricultural run-off. Riparian scrub typically is
dominated by wiilows and Fremont cottonwood, or by mulefat, broom baccharis, or tamarisk ( Tamarix
sp.), an introduced species. The understory is variable depending upon canopy coverage, disturbance
history and water availability, and usually includes poison-oak, desert grape, western ragweed
(Ambrosia psilostchya), rushes (Juncus spp.), and a variety of other hydrophytic (wetland) species.
Riparian scrub is a highly productive community, contributing to nutrient recycling and the
14
maintenance of water quality, and providing habitat for numerous species. However, lo( supports few sensitive plant and wildlife species. Characteristic well-developed riparian scrub
along El Camino Real south of Batiquitos Lagoon, extending east from the mudflats at the e
end of Agua Hedionda Lagoon (e.g., Macario Canyon), and along the northern portion of tl-
south of Highway 78 in Buena Vista Creek.
Oak Woodland
As used herein, oak woodland encompasses several closely related community types, includinj
live oak woodland, southern coast live oak riparian forest, and Engelmann oak woodland. I
Carlsbad, this community typically is restricted to mesic north-facing slopes, shaded ravine
drainages. It is dominated by coast live oak, with scattered individuals of other tree species, inc
western sycamore, willow, and Mexican elderberry. The understory includes toyon, laurel ,
California wild rose (Rosa califomica), poison-oak, and currant (Ribes spp.). Oak woodland i
limited in the City of Carlsbad; it is best developed in the drainage behind the Safety Cente
to the north and east.
Disturbed Wetland/Floodplain
Disturbed wetland or floodplain is not a native plant community. It typically occurs where the I
wetland vegetation has been degraded by mechanical activities or invaded by weedy, non.
species. This habitat is characterized by open and patchy vegetation that includes both nati
introduced species. The dominant shrubs include mulefat, broom baccharis, and scattered
trees. Other species present in varying density include coastal goldenbush (Isoc~oma veneta:
dock, castor-bean (Ricinus communis), cockle-bur (Xanthium strumarium), spiny rush, and F
grass (Cortaderia spp.).
Eucalvutus Woodland
Eucalyptus woodland also is a non-native community. It is dominated by various species of F
eucalyptus (Eucalyptus spp.) that survived around old dwellings or in entire groves (e.g., the
Grove). The understory is usually poorly developed or absent owing to the allelopathic (toxic:
of eucalyptus leaves that acts to inhibit the growth of other plants. Although this habitat su
no sensitive plant or wildlife species, it is often used for nesting by raptors and other birds or r(
by bats.
Disturbed Habitat
As used herein, the term disturbed habitat encompasses a wide variety of open, non-native h
that lack permanent structures and currently support activities that prohibit the siiccession of
plant communities. Four types of disturbed habitat are recognized: (1) typical disturbed habi
active disturbed habitat; (3) active agriculture; and (4) golf courses. Typical disturbed ha1
characterized by areas that have been graded, scraped, or subject to prior agricultural use.
areas either lack vegetation or support weedy, introduced species such as Russian-thistle, dovi
Australian saltbush (Atripla semibaccata), and black mustard. Typical disturbed habitat diffei
annual grassland by the abundance or domination of weedy species. For example, fallow agric
fields often become dominated by species such as Russian-thistle or black mustard. Active dis
habitat supports mineral extraction or other active uses that inhibit the growth of plants.
agriculture and golf courses are self explanatory, although what was active agriculture at this
may appear to be annual grassland or typical disturbed habitat in subsequent years. Whik
disturbed habitat types directly support few or no sensitive plant and wildlife species, they 1
used as foraging habitat by raptors and several mammal species.
B
1
Q
I
I
1
1
1
1
I
I
I
I
1
1
I
I
I
1
15
Developed
Developed areas are characterized by structures, parking lots, yards, roads, and a variety of buildings.
These areas support no native vegetation. Developed areas occupy the majority of the western half
of the City of Carlsbad, but occupy a considerably smaller pe:rcentage of the area east of El Camino
Real.
Own Water
Open water is aquatic habitat that lacks vascular vegetation and includes lakes, ponds, reservoirs, and
coastal lagoons and may be either fresh, brackish or saline. ’The area surrounding the open water is
almost always characterized by freshwater marsh, salt marsh, or riparian habitats. The largest bodies
of open water include the three major coastal lagoons (Batiquitos, Agua Hedionda, and Buena Vista),
Lake Calavera, and Squires Dam, although there are a number of artificial ponds throughout the City.
2.2.5 SENSITIVE BIOTA
A large number of plant and wildlife species recognized as sensitive, rare, threatened, or endangered
by CDFG, USFWS, California Native Plant Society (Smith antd Berg 1988), or local resource agencies
and conservation groups have been documented from the City of Carlsbad. These are discussed
below. Species records come from published sources cited herein, from EIRs and other unpublished
environmental documents and technical reports reviewed for the study (see Appendix B), and from
personal communications with local biologists familiar with various parts of the City.
Sensitive Wildlife Species
Birds
Several species of birds recognized as threatened or endangered by state or federal agencies occur
within Carlsbad as overwintering individuals or resident populations. These include the light-footed
clapper rail, Belding’s Savannah sparrow, and California least tern, all associated with coastal estuaries
and salt marsh habitats. The least Bell’s vireo, restricted tal riparian woodlands, and the federally-
proposed endangered California gnatcatcher, occurring primarily in coastal sage scrub communities
below about 1,200 feet (370 m), also have been reported from Carlsbad. The latter species is
widespread in coastal sage scrub habitats throughout Carlsbad. Other bird species that occur in
Carlsbad that are recognized as sensitive by the resource agencies include the coastal cactus wren,
Bell’s sage sparrow, southern California rufous-crowned sparrow, California homed lark, and several
species of raptors.
Accipiter coopen -- Cooper’s hawk
USFWS: None
CDFG Species of Special Concern
Cooper’s hawk ranges through most of California and is a common winter migrant in San Diego
County. In the county, Cooper’s hawk breeds almost exclusively in oak woodland habitats; in the
winter they may be found in any woodland habitat (Unitt 1984). Mature trees in suburban areas also
may support nesting Cooper’s hawks. Populations of this species have declined steadily throughout
the state probably as a result of habitat destruction, falconIy, and pesticide abuse (Remsen 1979).
Riparian areas and groves of mature trees within Carlsbad meet the habitat requirements of this
species.
16
Accipiter striatus -- sharp-shinned hawk
USEWS: None
CDFG Species of Special Concern
This species is also a Bureau of Land Management and U.S. Forest Service watchlist species d
declines in populations throughout its breeding range. The sharp-shinned hawk is a regular ‘v
migrant in San Diego County and may be encountered in any woodland habitat (Unitt 3
Riparian woodlands and suburban areas in Carlsbad represent potential habitat fix this speci
was reported from Rancho La Costa.
AimophiZa m.eps canescens -- Southern California rufous-crowned sparrow
USFWS: Candidate (Category 2)
1
#
1
I
1
1
I
I
1
8
I
I
1
I
1
I
1
1 CDFG None
The Southern California rufous-crowned sparrow is an uncommon to fairly common resident (
Diego County primarily found in coastal sage scrub that is known to occur in the City of Cz
(Unitt 1984). This species recently became a federal candidate €or listing as threater
endangered.
Ammodramus sandwichemis beldingi -- Belding’s Savannah sparrow
USFWS: Candidate (Category 2)
CDFG. Endangered
Belding’s Savannah sparrow ranges from Santa Barbara County, California south to about El R
Baja California, Mexico. It is a permanent resident in San Diego County (Unitt 1984). This
nests in salt marshes or the margins of lagoons in low vegetation dominated by pickl
Apparently, it prefers the upper littoral zone of tidal marshes, areas flooded only by high sp
storm tides (Massey 1977; Unitt f984), and it forages in marshes and nearby mudflats, beaches
and in low coastal strand vegetation. In Carlsbad, Belding’s Savannah sparrow has been re
from Batiquitos, Agua Hedionda, and Buena Vista lagoons.
Buteo lineatus -- red-shouldered hawk
USFWS: None
CDFG None
Audubon Society: Blue List, 19’72-1986
The red-shouldered hawk is an uncommon to fairly common resident in San Diiego CountJ
1984). It inhabits nearly the entire county west of the desert. Red-shouldered hawks 04
variety of woodland habitats, and stands of non-native trees (such as eucalyptus) may s
breeding habitat. Although concern has been expressed that the numbers id this spec
declining, Wilbur (1973) concluded that no major declines in population had occurred in Ce
except possibly in the Sacramento and San Joaquin valleys. These hawks can tolerate
presence if mature trees with a high canopy are maintained; they nest in oak and riparian wc 1 suburban areas, and orchards.
Campylorhynchus brunneicapillus sandiegensh -- San Diego (coastal) cactus wren
USFWS: Candidate (Category 2)
CDFG. Species of Special Concern
The cactus wren is a widespread and common species of the southwestern deserts, extendir
Pacific coast in southern California and Baja California. Rea and Weaver (1990) and others
to them recognize a portion of the coastal population as a separate subspecies, Campy101
17
brunneicapdlus sandiegensis. According to Rea and Weaver, the range of C. b. sandiegensis (the "San
Diego cactus wren") is restricted to the coastal slope of San Diego County, extreme southern Orange
County, and northwestern Baja California. Populations occurring north of southern Orange County
are assigned to the more common and widespread desert subspecies, C. b. anthonyi. Originally, all
coastal populations from the Mexican border north to Ventura County had been assigned to the
subspecies sandkgensis, but recently it has been concluded that populations in Orange, Los Angeles,
and Ventura counties more closely resemble C. b. anthonyi. It should be noted, however, that the
American Ornithological Union Committee on Taxonomy and Systematics has not yet accepted the
distinction between srandiegemik and anthonyi. Until they do 150, sandiegensis should be considered
a proposed subspecies.
Cactus thickets supporting large populations of the San Diego cactus wren in San Diego County
occur primarily in sage scrub and Diegan coastal sage scrub communities, such as those found in the
vicinity of San Pasqual, Lake Jennings, Sweetwater Dam, and Otay Mesa. Smaller populations occur
at Camp Pendleton, San Elijo and Batiquitos lagoons, and Fletcher Hills. Cactus wrens also recently
(ca. 1988) occurred north of Batiquitos and Agua Hedionda lagoons (H. Wier, pen. obs.). The San
Diego cactus wren formerly was far more common in the coastal lowlands. Population declines are
linked to loss of habitat, and in particular, loss of cholla and prickly-pear cactus thickets (Hix 1990).
The San Diego cactus wren currently is being evaluated for possible listing as threatened or
endangered by the USFWS.
Cathartes aura -- turkey vulture
USFWS: None
CDFG: None
Although not recognized as sensitive by the USFWS or the CDFG, the turkey vulture is considered
a declining species in San Diego County (Everett 1979). Unitt (1984) reports that this species is a
common spring and fall migrant, an uncommon to locally common winter visitor, and a rare to
uncommon summer resident in San Diego County. He further states that turkey vultures are
widespread throughout the county, particularly over open fields and grasslands.
Circus cyaneus hudsonius -- northern harrier
USFWS: None
CDFG: Species of Special Concern
On the national level, the northern harrier has been recognized as sensitive for many years by the
National Audubon Society. It ranges throughout California and may be encountered in grasslands,
open fields, and salt and freshwater marshes. According to Unitt (1984) the northern harrier is an
uncommon to fairly common migrant and winter visitor in San Diego County, and a rare and local
summer resident. This species is most common in the coastal lowlands, where as many as 10 (Tijuana
River Valley) and 19 (Sweetwater Reservoir) have been observed. Observations of displaying pairs
at Las Pulgas Creek and the Santa Margarita River suggest that small numbers of northern harriers
still breed on Camp Pendleton. Nests and nesting behavior also have been observed at French
Canyon, Sweetwater River, and Dennery Canyon.
EIanus caeruZeus -- black-shouldered kite
USFWS: None
CDFG None
Although not specifically designated as rare, threatened, or endangered by either CDFG or USFWS,
the black-shouldered kite is regarded as a locally sensitive raptor. Formerly the Kelly Ranch north
of Agua Hedionda Creek supported a communal roost for approximately 15 to 25 birds (H. Wier,
18
pers. obs.). The black-shouldered kite can nest in riparian woods and large shrubs in coasta
scrub and chaparral.
Empidonax traillii atimus -- southwestern willow flycatcher
USFWS: Candidate (Category 1)
CDFG None
The southwestern willow flycatcher is an uncommon spring and fall migrant found through0
Diego County (Unitt 1984). Nesting pairs use willow thickets in riparian woodland. There
records of this species from Carlsbad, but it may occasionally use the same habitat in the City 2
by the least Bell's vireo in the past (i.e., Macario Canyon and Buena Vista Creek:).
Eremophila alpestris actiQ -- California horned lark
USFWS: Candidate (Category 2)
CDFG None
The California homed lark is a common breeding resident, and an abundant migrant and
visitor (Unitt 1984). It is commonly found in both native and non-native grasslands, iI
agricultural land, and along sandy ocean or bay shores. The homed lark has become a candid
listing as threatened or endangered, apparently because of rapid development of its habitab
species is likely to be relatively common in Carlsbad.
Lanius ludovicianus -- loggerhead shrike
USFWS: Candidate (Category 2)
CDFG None
The loggerhead shrike is a relatively common resident of San Diego County found around agril
land, native and non-native grassland, and broken coastal sage scrub and chaparral (Unitt 198'
small raptor became a federal candidate for listing as threatened or endangered because c
development of its habitats. Development not only threatens nesting areas for the shrike, but
base as well (including insects, lizards, and small rodents).
Pelecanus occidentalis califomicus -- California brown pelican
USFWS: Endangered
CDFG Endangered
The California brown pelican is a common to very common non-breeding visitor along the S
California coast (Unitt 1984). This species was listed as endangered by the state and
governments as a result of reproductive failures, and consequent precipitous population declii
to DDT contamination in the 1960s and 1970s.
This species is commonly seen along the coast and lagoons in Carlsbad.
Phalacrocorax auntus -- double-crested cormorant
USFWS: None
CDFG: None
This species is a common non-breeding visitor in San Diego County (Unitt 1984). It is obser-
frequently on bays, lagoons, and estuaries along the coast (Unitt 1984), but also inay be encc
on ponds at inland localities. Everett (1979) considers the double-creasted cormorant as a "d
species in San Diego County. He indicates that it formerly bred at Lake Henshaw, but
I
I
I
I
I
1
1
I
I
I
8
1
I
1
I
t
I
I
1 19
nested in the county since about 1933. This species occurs i3t Agua Hedionda, Buena Vista, and
Batiquitos lagoons, and likely uses larger inland lakes as well.
Polwptila califomica -- California gnatcatcher
USFWS: Proposed endangered
CDFG None
The California gnatcatcher is a small gray nonmigratory bird with a black tail with white edges. In
the breeding season the male has a black cap. It eats insects and builds a small, cup-shaped nest of
plant material, animal hair, and spider webs.
The present known range of the California gnatcatcher extends from an isolated population on the
Palos Verdes Peninsula of Los Angeles County, and southern'orange, western Riverside, and San
Diego counties, into northern Baja California, Mexico. It is an obligate resident of coastal sage scrub
and Riversidean (inland) sage scrub communities, although it may use adjacent disturbed, chaparral,
and riparian habitats. Individuals of this species are generally found at elevations below 800 feet
along the coast, and below 1600 feet in Riverside County (Atwcd 1990). Based on average territory
size and available habitat, Atwood (1990) estimated that 1,200~-2,000 pairs were resident within the
state in 1990.
A pair of gnatcatchers may forage over 6 to 45 acres of land during the breeding season (generally
the end of July to the end of June), and may forage more widely at the end that period. In Carlsbad,
gnatcatcher territories probably are less than 20 acres due to the coastal location and constrained
condition of most of the suitable habitat locations (Mock 1992).
The California gnatcatcher has no special status with the CDFG, although it formerly was listed (as
Polwptila melanura) as a second priority "Species of Special Concern." The USFWS has proposed
endangered status for the California gnatcatcher pursuant to the Endangered Species Act of 1973.
Although a decision by the USFWS on the status of the gnatcatcher originally was due in September
of 1992, the "final rule" probably will not be issued until January 1993.
In San Diego County, gnatcatcher populations are known from several sites along the coast and from
as far inland as San Pasqual, Poway, Lakeside, Escondido and Ramona. The California gnatcatcher
is widespread throughout the coastal sage scrub areas of Carlsbad. The largest populations are
concentrated in the northeastern and southeastern portions of the City.
Rallus longirostris levipex -- light-footed clapper rail
USFWS: Endangered
CDFG: Endangered
This subspecies ranges from about Santa Barbara south into northern Baja California, Mexico (Unitt
1984). In San Diego County, it is an uncommon and very localized resident of tidal salt marshes that
support large stands of cord grass (Spartzna folwsa) (Unitt 1984). It may also occur in brackish
marshes dominated by cattails.
The status of the clapper rail in San Diego County has been monitored closely since about 1973 by
P. Jorgensen (Wilbur 1974; Wilbur et al. 1979) and the USFWS. Clapper rails formerly were much
more common in the County. Its range and numbers have been reduced greatly by destruction and
degradation of salt marsh habitats. Census results from 1973 through 1981 indicate that the total San
Diego County population size fluctuates between about 55 arid 75 pairs; the total population in
California was 173 pairs in 1981 (Unitt 1984). In Carlsbad, the light-footed clapper rail has small
populations, but it has been reported from Batiquitos, Agua Hedionda, and Buena Vista lagoons.
20
Sterna antillarum browni -- California least tern
USFWS: Endangered
CDFG: Endangered
The California least tern is a common, but very localized, summer resident and migrant in San :
County (Unitt 1984). This species nests colonially along the coast on barrier dunes at river mc
lagoon entrances, and along sandy strips. Within Carlsbad, the least tern has nested at the
Hedionda, Batiquitos, and Buena Vista lagoons in the past (Unitt 1984). Threats to this specie3
from development of suitable nesting areas. This forces the least tern to use fewer nesting area
increasing the risk of whole colony failure due to local predation and other disturbances.
Vweo bellii pusiZIus -- least Bell’s vireo
USFWS: Endangered
CDFG Endangered
Least Bell’s vireo is a small, gray and white, migratory songbird that inhabits willow-dorr
riparian areas of southern California and adjacent northern Baja California, N[exico (San
Association of Governments 1988). It is one of four North American subspecies of Bell’s
Historically, this subspecies was abundant in riverine habitats from Baja California to Tehama (
in central California (Grinnell and Miller 1944; Willett 1933), with the center of its breeding
in the Sacramento and San Joaquin Valleys. Widespread destruction of its obligate riparian
for agricultural use, livestock grazing, flood control, urban development, and various commercii
in combination with increased brood parasitism by the exotic brown-headed cowbird (MoZolhm
decimated vireo numbers, extirpating it from the central valleys, and restricting the species tc
fragmented populations in a fraction of its former range (USFWS 1988). By 1!985, only 2E
were known from 45 locations in 9 counties (USFWS 1988). In response to the unparalleled
of this passerine, the least Bell’s vireo was listed as endangered by the CDFG in 1980, and
USFWS in May 1986.
The two Carlsbad records of which we are aware are males from Macario Canyon ((feeding a fl
in 1987) and Buena Vista Creek (H. Wier, pers. obs. circa 1983).
Reptiles and Amphibians
Reptiles documented from Carlsbad that are recognized as federal Category 2 candidates fo
as threatened or endangered by the USFWS or as Species of Special Concern by CDFG inch
Diego horned lizard, orange-throated whiptail, western whiptail, and northern red d
rattlesnake. Other sensitive reptiles likely to be present include two-striped garter sna
southwestern pond turtle. The western spade-foot toad, recognized as a Species of Special (
by CDFG, also has been recorded from the City.
Cnemidophorus hyperythrus beldingi -- orange-throated whiptail
USFWS: Candidate (Category 2)
CDFG Species of Special Concern
The orange-throated whiptail is a small, slender, insectivorous lizard with a bright orange F
its throat. It occurs in the United States and Mexico, ranging from southern California (we:
transverse and peninsular ranges) south to about mid-way through the peninsula of Baja Ca
This species has exhibited population declines in California associated with the conversion o
sage scrub and dry wash habitats for agriculture, urban development, and flood control. P
forager, the orange-throated whiptail frequents dry, often rocky hillsides, ridges, valleys, anc
that support broken coastal sage scrub, chaparral, mule fat scrub, and grassland mixed with sa
1
I
I
I
I
1
I
I
1
8
I
1
I
1
I
1
I
I
I
21
I
species. It often occurs with the more common western whiptail (C. ti@). The orange-throated
whiptail relies to some extent on the burrows of small mammals, such as the California ground
squirrel (Spemzophilus beecheyq, for protection from predators and adverse environmental conditions.
This species was recorded on the Alanda project site located near El Camino Real in the
northeastern portion of the City, and from an area located south of Palonnar Airport Road and west
of El Camino Real.
Cnemidophonu ti@ multkutatus -- coastal whiptail
USFWS: Candidate (Category 2)
CDFG None
The coastal whiptail is an active lizard that inhabits sparse coastal sage scrub habitat that provides
room for running (Stebbins 1985). This species avoids dense shrub vegetation and grasslands. It was
recently added to the candidate species list because of threats to its habitat by development. The
coastal whiptail is likely to occur on more open, drier south-facing slopes in Carlsbad.
Crotalus ruber -- northern reddiamond rattlesnake
USFWS: Candidate (Category 2)
CDFG: None
The northern red-diamond rattlesnake inhabits coastal sage scrub, chaparral, and open woodlands
(Stebbins 1975). This species is relatively common in the coastal sage scrub community in San Diego
County. However, it was added to the federal candidate list because of threats to its habitat by
development. This species is highly likely to occur in the City of Carlsbad.
Phymosoma coronaturn blainvillei -- San Diego horned lizard
USFWS: Candidate (Category 2)
CDFG: Species of Special Concern
The San Diego homed lizard is a small, spiny, somewhat rounded lizard that occurs primarily in open
areas in coastal sage scrub communities. It was a common species in San Diego County until about
10 years ago (Hix 1990). Three factors have contributed to its decline: loss of habitat, over
collecting, and the introduction of exotic ants. In some places, especially adjacent to urban areas, the
introduced ants have displaced the native species upon which tbe lizard feeds. This species has been
recorded in the northeastern part of the City just west of Lake Calavera and to the northeast of Agua
Hedionda Lagoon.
Thamnophis hammondi -- two-striped garter snake
USFWS: Candidate (Category 2)
CDFG None
Although it currently receives no state or federal protection, the two-striped garter snake is
recognized as a threatened species by the San Diego Herpetological Society (McGurty 1980). It
occurs primarily in wetlands, particularly freshwater marsh and riparian scrub habitats. Although it
has not been reported from Carlsbad, it is likely to be resident.
Scaphwpus hammondi -- western spade-foot toad
USFWS: None
CDFG: Species of Special Concern
The western spade-foot toad is primarily a species of the lowlands, frequenting washes, floodplains
of rivers, alluvial fans, alkali flats (Stebbins 1985), temporary ponds, and vernal pools. It is considered
22
sensitive because of declines in populations associated with loss of habitat. This; species has
reported from the Woolley project.
Mammals
No mammal species presently known to occur in the City are recognized as threatened or endar
by the USFWS or CDFG. Five federal Category 2 candidate species are highly likely to oc
Carlsbad: the San Diego black-tailed jackrabbit, San Diego desert woodrat, sou them grassh
mouse, Dulzura California pocket mouse, and northwestern San Diego pocket mouse. Three
mammal species recognized as federal Category 2 candidates for listing as threatened or endar
have a remote chance of occurring at least occasionally in Carlsbad. These include the Pacific
mouse, California mastiff bat (Eumops perotis caZifomicus), and spotted bat (Eucllerma rnacui
The Pacific pocket mouse has been recorded near the coast in the City of Oceanside but otk
is extremely rare within its historic range (Bond 1977). None of the bat species has been rei
in Carlsbad, and there are relatively few suitable roosting sites for bats within the City limit:
California mastiff bat, which has been recorded from near Lake Hodges, and the spotted b;
require rugged, rocky areas with crevices for roosting. Both of the bats could occur in the City
foraging bouts to take advantage of insects around agriculture and wetland areas or to utilize
at lakes, streams, or swimming pools.
In contrast to our knowledge of the distribution of plant and bird species, the status 01
mammals is poorly known. Most mammals are secretive and nocturnal or crepuscular (active i
dusk or twilight) and are not readily identifiable unless captured and examined close at hand.
has been much less field work on the occurrence and distribution of mammals in the City of Ci
particularly small mammals and bats.
Lepus califomicus bennettii -- San Diego black-tailed jackrabbit
USFWS: Candidate (Category 2)
CDFG None
The San Diego black-tailed jackrabbit is found in open sage scrub habitat and grassland.
recently added to the federal candidate list because of threats to its habitat by development.
Diego County, it is known from San Marcos, Escondido, San Diego area, Janiul Creek, i
Laguna Mountains (Bond 1977). It is highly likely to occur in Carlsbad.
Neotoma lepida intermedia -- San Diego desert woodrat
USFWS: Candidate (Category 2)
CDFG: None
The San Diego desert woodrat inhabits areas with heavy growth, such as dense coastal sag
chaparral, cactus, or rock crevices. This species was recently added to the federal candic
because of threats to its habitat from development. In San Diego County, it is known fi
Bonsall, Mission San Luis Rey, Mission Gorge, Murphy Canyon, Murray Dam, and San Diel
(Bond 1977). Despite no collections specifically from the City of Carlsbad, these records es!
surround the City and, thus, the species is likely to occur there.
Onychomys torridus ramoncl -- southern grasshopper mouse
USFWS: Candidate (Category 2)
CDFG None
ne southern grasshopper mouse is a stout mouse with a relatively short and thick tail. Thi!
primarily feeds on insects, but is known to capture and devour other rodents. Grasshopper
I
1
I
I
I
1
I
1
8
1
1
I
I
1
I
8
1
I
I
23
interesting in that they emit audible "howls" upon leaving their day burrows. The grasshopper mouse
is relatively uncommon throughout its range compared to other rodent species such as deer mice
(Peromyscus spp.). 0. t. ramona is found in the lower and upper Sonoran life zones of the Pacific
slopes, and in San Diego County has been recorded from Carlsbad, Culp Valley, Dulzura, San Diego,
' San Pasqual Valley, and Tijuana River Valley (Bond 1977). Continued urbanization of the coastal
region threatens the existence of this subspecies.
Perognathus (Chaetodipus) califomicus fernoralis -- Dulzura California pocket mouse
USFWS: Candidate (Category 2)
CDFG None
The Dulzura California pocket mouse typically is found on slopes dominated by chaparral or oaks.
It is a relatively common pocket mouse within its preferred habitat. It was given candidate status
apparently because of rapid depletion of its habitat in Southern California. In San Diego County,
this species has been recorded from Banner, Campo, Dehesa, Dulzura, Escondido, Pala, Rainbow,
Ramona, Palomar Mountain, San Marcos, Santee, Santa Ysabel, and Witch Creek (Bond (1977).
Because of the proximity of these records to Carlsbad (e.g., !Sari Marcos), the Dulzura California
pocket mouse is almost certainly an inhabitant of the City.
Perognathus (Chaetodeus) fallax -- northwestern San Diego pocket mouse
USFWS: Candidate (Category 2)
CDFG. None
The northwestern San Diego pocket mouse inhabits sparse or disturbed coastal sage scrub or
grasslands with sandy soils. This species was recently added to the federal candidate list because of
threats to its habitat by development. In San Diego County, it is known from Del Mar, Dulzura,
Jacumba, Lake Hodges, Pala, San Diego area, and San Marcos (Bond 1977). Although these
collection localities do not specifically include Carlsbad, they surround it and, thus, the species is
highly likely to occur in the City of Carlsbad.
Invertebrates
Four species of butterflies that are resident or potentially resident within the City of Carlsbad are
recognized as federal Category 2 candidates for listing as threatened and endangered: Harbison's dun
skipper, salt marsh skipper, Hermes copper, and quino checkerspot. Although only the salt marsh
skipper has been documented from Carlsbad, Harbison's dun skipper and Hermes copper are highly
likely residents. Both are host specific insects and usually are encountered wherever their larval
foodplants occur. The larvae of Harbison's dun skipper feeds exclusively on San Diego sedge (Carex
spissa), which has been reported from several oak woodland and riparian areas within the City. The
larvae of Hermes copper feed on redberry (Rhamnus crocea), which is a common species throughout
much of the chaparral in the City. In addition to these sensitive butterflies, the federal Category 2
candidate globose dune beetle, a resident of coastal dunes, may be present in small remnants of dunes
along the coastal margins of the City.
Euphyes vestri5 harbisoni -- Harbison's dun skipper
USFWS: Candidate (Category 2)
CDFG None
Harbison's dun skipper is a medium-small, chocolate brown butterfly restricted to riparian habitats
where its larval host, San Diego sedge (Carex spksa), grows. It occurs in a series of scattered and
disjunct colonies throughout western San Diego County, extending as far north as the Santa Ana
Mountains of Orange County (Brown and McGuire 1983). The insect is single brooded (one
24
generation per year); the flight period extends from late May to early July. Several instan
extirpation are documented for populations of Euphyes vestris in San Diego County.
Wherever Carex spissa is found, Harbison’s dun skipper also is likely to be present. Carex spis
been documented ’from several riparian areas within Carlsbad. The most likely Carlsbad
supporting a population of the Harbison’s dun skipper is the riparian scrub habitat along El C
Real in the Evans Point area.
Panoquina mans -- salt marsh skipper
USWFS: Candidate (Category 2)
CDFG None
The salt marsh skipper is restricted to the narrow coastal margin from about Santa Barbara (
south to the southern tip of Baja California, Mexico (MacNeill 1%2; Donathue 1975).
represented by a series of disjunct and isolated populations confined to coastal estuarine or salt
habitats. The single larval host is salt grass (DistkhZis spkata) with which adults are con
associated (Emmel and Emmel 1973; Brown 1981). Owing to the apparently tolerant and ii
nature of salt grass, some colonies of the salt marsh skipper have managed to penist despite
habitat alteration. Nectar sources for the skipper include heliotrope (Heliotroprtvn curvassa
salty Susan, sea rocket, deerweed, and frankenia (Frankenia salina) (Brown 1981; Busnardc
The flight period of the salt marsh skipper extends from March or April to October in mos
in a series of overlapping generations. Population density reaches its highest in mid-to-late SI
The salt marsh skipper is resident in several protected areas in Southern California. Becausc
reduction in acreage of the salt marsh habitat in southern California, the salt marsh ski
considered highly sensitive. Populations of the skipper are disappearing rapidly in Baja Ca
as coastal marshes are being altered for salt production and other developments.
The salt marsh skipper has been observed at the east end oE Agua Hedionda Lagoon, and it
to be resident in salt marsh habitats around Batiquitos and Buena Vista lagoons.
Sensitive Plant Species
Within the City of Carlsbad, 20 species of plants recognized as regionally sensitive by the C;
Native Plant Society (Smith and Berg 1988) have been detected. These species are discussec
Acanthomintha iZiCifoZhz -- San Diego thorn-mint
USFWS: Candidate (Category 1)
CDFG Endangered
CWS: List lB, 3-3-2
San Diego thorn-mint is an aromatic, spring-blooming (April-May) annual, 0.5-1.5 dm t:
flowers occur in whorls that are subtended by several bracts armed with needlelike spines --
name “thorn-mint”. It is restricted in distribution to San Diego County and adjacent Baja Ci
Mexico. San Diego thorn-mint occurs on day lenses of several geologic origins on mesas ar
below 500 m (1,600 ft) elevation and is associated with Diegan coastal sage scrub, chapa
native grassland. In San Diego County, the species is known from Encinitas and San Marc to Sweetwater and Otay Lakes (Beauchamp 1986). The species also is known from th
elevations of McGinty Mountain and Poser Mountain.
Reported from the Woolley Annexation Project, the Carlsbad Land Investors project, anc
Hills Mobile Home Park project.
I
i
1
I
I
1
1
1
1
I
1
1
1
I
1
1
1
I
n
25
Adolphia caZifomica -- California adolphia
USFWS: None
CDFG None
CNPS: List 2, 1-2-1
California adolphia is a moderate-sized (0.5-1.0 m) profusely branched, rigid, spiny shrub, ranging
from western San Diego County, California, south into adjacent northwestern Baja California, Mexico
(Wiggins 1980). It generally occurs on clay soils in dry canyons and on hillsides on south-facing slopes
and washes in chaparral and coastal sage scrub communities below 300 m (965 ft) elevation. It
blooms in early winter to spring (December-May). In Sara Diego County it has been reported from
Morro Hill, Cemo de Calavera, Agua Hedionda, Rancho Santa Fe, Mount Soledad, Bernardo, Chollas
Valley, Barrett Junction, and Proctor Valley (Beauchamp 1986). This species is threatened by
urbanization, which has reduced considerabIy its former range (Smith and Berg 1988).
The California adolphia has been reported from numerous localities in the City, including Arroyo La
Costa, Airport Business Center, Santa Fe Glens, La Costa Northeast Annexation, Woolley
Annexation Project, Carbbad Highlands, the east end of Dove Lane, western portion of Rancheros,
Rancho Carrillo, Lake Calavera, Evans Point, Camino Hills Mobile Home Park, and others.
ArctostaphyZos glandulma ssp. crassv0Zi.a -- Del Mar manzanita
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List 1B (Reinstated, see below)
Del Mar manzanita represents the coastal form of San Diego County's common burl-forming
manzanita, and it is one of several sensitive plants that are inldicators of the unique and depleted
southern maritime chaparral habitat. Because of taxonomic difficulties, the California Native Plant
Society (Smith and Berg 1988) and the California Natural Diversity Data Base previously did not
recognize this taxon as sensitive. In a recent treatment ofArcto!rtaphyZos, Wells (1990) considers ssp.
crassif0i.a as a valid taxon representing those populations in coastal San Diego County and adjacent
northern Baja California (Munz 1974). CNPS botanist Mark Skinner has proposed to reinstate Del
Mar manzanita as a List 1B species. This species was reported from Arroyo La Costa and Rancho
Carrillo, and a few others.
Artemisia palmen -- San Diego sagewort
USFWS: None
CDFG: None
CNPS: List 2, 2-2-1
San Diego sagewort is a summer-blooming (July-September) weak shrub with long (0.5-0.8 m)
wandlike stems (Munz 1974). It is restricted in distribution to San Diego County and Baja California.
It typically occurs at low elevations (below 660 m) along intermittent streams and arroyos. In San
Diego County it has been recorded from Ramona, Mt. Woodson, Del Dios, Poway, and at several
sites from Tecolote Canyon south to the international border arid east to Jamul (Beauchamp 1986).
In Carlsbad this species is common in a drainage surrounded by chaparral adjacent to El Camino
Real, south of Palomar Airport Road.
26
Brodiaea flfolia -- thread-leaved brodiaea
USFWS: Candidate (Category 2)
CDFG: Endangered
Thread-leaved brodiaea is a rare, herbaceous, spring-blooming (May-June) perennial, wil
grasslike leaves and violet flowers. It grows in heavy clay soils that form open areas in coast:
scrub and chaparral communities below about 600 m (2,000 ft). It is found primarily in grasslai
vernal pool habitats. In San Diego, thread-leaved brodiaea is known from Alta Loma Creek,
Thibodo Ranch, Buena, San Marcos Hills, and Agua Hedionda (Beauchamp 1986). This spec’
reported from the Camino Hills Mobile Home Park project and west of Calavera Hills, and hz
the subject of a revegetation program at the Camino Hills site.
Brodiaea orcuttii -- Orcutt’s brodiaea
USFWS: Candidate (Category 2)
CDFG None
1.
i
i
I
1
t
8
1
1
1
I
I
1
I
t
I
1
1
I CNPS: List lB, 1-3-2
Orcutt’s brodiaea is a herbaceous, spring-blooming ( April-July) perennial that grows from 2
It is found only in San Diego County, the Santa Rosa Plateau in Riverside County and northe
California, Mexico (Wiggins 1980). It occurs in association with vernal pools, streams, anc
In San Diego County, the species occurs infrequently in coastal and foothill regions below 3
(4,827 ft) elevation. Reported localities include the Santa Margarita Mountains, 3an Marcos,
Henshaw Dam, Santa Ysabel, Cuyamaca Mountains, Miramar Naval Air Station, R
Buschalaugh Canyon, Japatual Valley, Woodwardia Canyon, Cedar Canyon, Otay Mountain,
Mountain and lower Otay Reservoir (Beauchamp 1986). This species was reported from An
Costa.
Ceanothus vermcosus -- wart-stemmed ceanothus
USFWS: Candidate (Category 2)
CDFG None
CNPS: List 2, 1-2-1
Wart-stemmed ceanothus is an erect, stiff-branched, rounded, evergreen shrub, 1.0-3.0 m t
occurs on dry hills and mesas in coastal and mixed chaparral habitats below 300 FL (965 ft) in
San Diego County and adjacent Baja California, Mexico. It is a spring-blooming species, fl
from January to April (Munz 1974). Beauchamp (1986) reports this species from Agua He
Encinitas, Leucadia, Torrey Pines State Reserve, Kearny Mesa, Lake Hodges, and Point LC
Baja California wart-stemmed ceanothus ranges from the Pacific coast to the foothills of th
Juarez and Sierra San Pedro Martir (Wiggins 1980). This species was reported from sevei
in the City, including Arroyo La Costa, Rancho La Costa, and the south end of Batiquitos
Comarostaphylk divemfoh ssp. diversifolia -- summer-holly
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List lB, 2-2-2
Summer-holly is a large shrub generally occurring on north-facing canyons and slopes and
washes in chaparral and foothill habitats below 700 m (2,297 ft) in scattered locations from tb
coast in San Diego County south into Baja California. Reported localities in the County inc
Marcos Mountains, Mount Whitney, Rancho Santa Fe, Gonzales Canyon, Encini tas, Mount
Penasquitos Canyon, Del Mar Heights, Iron Mountain, canyons of Mission Valley, Jamul V:
27
Otay Mountain (Beauchamp 1986). This species was reported from Arroyo La Costa, the Airport
Euphorbia misera -- cliff spurge
USFWS: None
CDFG None
CNPS: List 2, 2-2-1
Cliff spurge is a moderately large (0.3-1.0 m) irregularly branched shrub that occurs along sea
and in coastal sage scrub. This species is distributed from Orange and Riverside counties, Calif
to Baja California, Mexico, and on San Clemente and Santa Catalina Islands. In San Diego G
cliff spurge occurs from about Carlsbad south to the international border. It is relatively COI
but extremely local in southwestern San Diego County- In adjacent Baja California, it extends
almost to the 28th parallel (Wiggins 1980).
Cliff spurge is known from one locality in Carlsbad -- a small patch of maritime succulent scrut
of Windsong Shores.
FritiEIaria biflora -- chocolate lily or mission bells
USFWS: None
CDFG None
CNPS: Considered, but rejected: Too common
Chocolate lily is a small herbaceous perennial, 15-40 cm in height, with large, nodding, dark
to greenish purple, bell-shaped flowers. It is in bloom from about January through April. Chc
lily is occasional on open slopes with clay soils in native grassland and sparse coastal sagc
communities below about 700 m (2,297 ft). It ranges from San Diego and Riverside countie
to Mendocino County (Munz 1974). In San Diego County it has been recorded from up€
Onofre Canyon, San Marcos, Rancho Santa Fe, Bernardo, Del Mar, San Diego, Point Loma, I
McGinty Mountain, Santee, and several other localities (Beauchamp 1986). Although the chi
lily has a relatively broad distribution in coastal California, the fact that it is restricted to
grasslands, a rare and depleted habitat, suggests that it should be considered a sensitive spec
Carlsbad, this species has been reported from Bressi Ranch (south of Palomar Road/eas
Camino Real).
HarpagonelZa palmen var. palmen -- Palmer’s grappling-hook
USFWS: None
CDFG: None
CNPS: List 2, 1-2-1
This widely-distributed, diminutive annual occurs in Los Angeles, Orange, Riverside, and Sal
counties, and also on San Clemente Island, in Arizona, in Baja California, and in Sonora,
It typically grows on clay soils and burns below 1,OOO m (3,280 ft) elevation, and flow<
February to April (Munz 1974; Wiggins, 1980; Beauchamp 1986). In San Diego County, 1
grappling hook is reported in Guajome Mesa, Rancho Santa Fe, Olivenhain, Paway Grade,
Mesa, Emerald Hills, Mission Gorge, Otay, Dehesa, Rice Canyon, Table Mountain, and Box
(Beauchamp 1986). This species was reported from Calavera Hills.
Iva hayesiana -- San Diego marsh-elder, poverty weed
USFWS: Candidate (Category 2)
CDFG: None
CNPS: List 2, 2-2-1
This low perennial shrub occurs in southwestern San Diego County and northern Baja C
(Munz 1974; Smith and Berg 1988). It grows in low-lying, moist or alkaline places along intf
1
1
I
I
1
I
I
1
8
1
1
I
8
il
I
I
R
I
1
29
streams in coastal areas. Although it has a fairly restricted range in San Diego County, San Diego
marsh-elder is apparently more widespread to the south, ranging into central Baja California (Wiggins
1980). San Diego marsh-elder often grows in association with spiny rush and other indicators of
wetland habitat (Reed 1988). San Diego marsh-elder may be a dominant understory plant in
disturbed floodplain situations such as that in the Otay River Valley. Its habitat in southwestern San
Diego County is threatened by coastal development and channelization of local streams and rivers.
Muilla cIevelandii -- San Diego golden-star
USFWS: Candidate (Category 2)
CDFG None
CNPS: List lB, 2-2-2
San Diego golden-star is found only in southern San Diego County and adjacent northwestern Baja
California, Mexico. This spring-blooming (March-May), herbaceous perennial occurs infrequently on
clay soils on dry mesas and hillsides and among vernal pools in Diegan coastal sage scrub or chaparral.
Primary threats to this species are illegal dumping, off-road vehicle activity, and urbanization (Smith
and Berg 1988). A survey of herbarium specimens collected in the past century and deposited at the
San Diego Natural History Museum indicates that few previous localities for this plant still exist in
an undeveloped state or condition otherwise suitable for supporting populations of this plant. Extant
populations include those in vernal pool habitats on Naval Air Station Miramar, west of Rancho
Bernardo, and San Ysidro Mountains. In Carlsbad, large populations occur on the Rancheros
property and south of Rancho Santa Fe Road.
Juncus acufus var. sphaerocarpus -- spiny rush
USFWS: None
CDFG None
CNPS: List 4, 1-1-3
This large (0.5-1.5 m), tufted, perennial rush, with stout, rigid stems, is encountered frequently in
alkaline seeps and marshes or in areas adjacent to these. Spiny rush has a wide distribution from San
Luis Obispo County south to Baja California and east to Imperial County and Arizona, although
some doubt exists regarding the taxonomy of eastern populations. Although urbanization represents
a serious threat to spiny rush (Smith and Berg 1988), the abundance of this plant in many widely
separated wetlands, together with the current application of protection for these habitats, indicates
a rather low threat to this species. This species was reported from the La Costa Development,
Batiquitos Pointe Site, west side of Batiquitos Lagoon, Lake Calavera, Buena Vista, Evans Point,
Buena Vista Creek, and other locations.
Quercus engelmannu -- Engelmann oak
USFWS: None
CDFG: None
.
CNPS: List 4, 1-2-2
Engelmann oak is a moderately large tree with gray-green foliage, whitish and shallowy furrowed
bark, and an open, airy appearance. It generally occurs on mesas and open slopes in foothill and
coastal areas below about 1,300 m (4,200 ft), in San Diego, Riverside, and Orange counties and
northern Baja California. It may occur in closed canopy riparian woodlands dominated by coast live
oak or in more monotypic stands as an oak savanna on moist north-€acing slopes. This oak occupies
the smallest range of any oak tree in the southwestern United States (Scott 1990); the center of its
distribution is cismontane San Diego County. Engelmann oaks are sensitive to land management
practices such as fire, and their small, disjunct woodlands are highly susceptible to extirpation.
Individual trees typically live from 50 to 80 years; however, a few trees in every woodland may be 150
30
to 350 years old (Scott 1990). This species was recorded from the woodland areas south of Pz
Airport Road west of El Camino Real (SW Quad).
Selaginella cinerascens -- ashy spike-moss or mesa ciubmoss
USFWS: None
CDFG: None
i
1
1
I
I
I
I
i
1
I
I
1
I
1
1
I
1
I
I CNPS: List 4, 1-2-1
This tiny, prostrate, whitish gray, moss-like plant occurs in San Diego County and ad
northwestern Baja California, Mexico. In San Diego County it ranges from about Rancho Bel
south to the international border. It is relatively abundant in coastal areas, occurring on flat
below 300 m (%5 ft), that are prime locations for housing. Development of these areas has (
massive reduction of the habitat of the ashy spike-moss. Although this plant is one of thc
common understory plants in Diegan coastal sage scrub and coastal chaparral cornmunit'
extremely restricted geographical range and the rapid disappearance of its primary habitats cc
to make it a sensitive resource. This species was reported from Arroyo La Costa, Airport B
Center, Woolley Annexation Project, Carlsbad Highlands, western side of Rancheros, inter:
(NW) of Alga Road and El Camino Real, north of N end of Ambrosia Lane, Rancho Card
Evans Point.
Solanum tenuiiobatum -- narrow-leaved nightshade
USFWS: Candidate (Category 2)
CDFG None
CNPS: List lB, 3-1-3
This purple-flowered, low, woody shrub occurs infrequently between 200 and 1,100 m (656 tc
ft) elevation in chaparral habitats in southern San Diego County and Baja California. It is
from Jamul, Lyons Valley, Otay Mountain, Potrero Grade, Barrett Dam, Silvewood, (
(Beauchamp 1986), the east slope of San Miguei Mountain (PSBS 1980), the eastern end
Sweetwater River Valley, and near Mussey Grade Road near Ramona (F. T. Sproul, pers. c
This species was reported from Carlsbad Highlands.
Other Key Species
In addition to sensitive wildlife and plant species, there also are several key wildlife species
presence in Carlsbad reflect the overall health and viability of the City's natural resources. A
of these species includes mule deer (Odocoileus hembnus), bobcat (Felzk mfus), gray fox (t
cinereoargenteus), coyote (Canis latrans), and golden eagle (Aquila chyaetos). The conse
program and preserve system developed by the City should consider the requirements of these
as well.
31
/
i
\
SECTION
ome Inve ry and Mdpl
,
.,
/ \
\
-& AND HABITAT h&YSIS "4 in suppoyt of the ClTY OF CAIUSBAD HABITAT WAGEMENT PLAN ,
SECTION 3
RESOURCE INVENTORY AND MAPPING
1
I
I
I
1
1
1
1
I
I
R
I
I
1
1
3.6 INTRODUCTION
The resource analysis for the HMP focused on two major biological tasks: (1) accumulatio
biological inventory and mapping of habitats and sensitive species present within the City of Ca
and (2) identification of a potential interconnected preserve system to accommodate both re1
common and sensitive biological resources. This section details the methods and results of tf
task. The second task included analyses of habitat value and habitat sensitivity, which are des
in detail in Section 4.
The study focused on undeveloped areas within Carlsbad, with particular emphasis on large
connected areas of undisturbed native habitat. The majority of the data for the biological re
analysis was obtained by reviewing environmental documents, topographic maps, and
photographs made available through the City of Carlsbad, resource agencies, and lando
developers. A limited amount of field surveys were conducted to check the accurixcy of the m
efforts. Data from areas immediately adjacent to the City of Carlsbad @e., Encinitas ai
Marcos) also were reviewed, because of their relevance to establishing wildlife corridors and
linkages to offsite open space areas.
3.2 MATERIALS
Data for the biological inventory and mapping effort were obtained from a variety of source:
primary source of data was the library of the City of Carlsbad, which includes over 50 bic
resources reports from EIRs and other environmental documents for projects proposed wit1
City from 1978 to present (see Appendix B). Because the reports represent a variety of prc
developments, have been written by a variety of biologists, and cover a wide range of years, tl
highly variable in their thoroughness and coverage. Most of the reports include vegetation
locations of sensitive species, lists of plant and wildlife species observed, and descriptions of
types.
Additional data regarding sensitive species and habitats present within the City of Carlsbai
obtained from the California Natural Diversity Data Base (CNDDB) (USGS quadrangles S;
Rey, San Marcos, Encinitas, and Rancho Santa Fe), the California Native Plant 'Society's In1
of Rare and Endangered Vascular Plants (Smith and Berg 1988), Report on the California But
Listed as Candidates for Endangered Status by the USFWS (Murphy lw), Eleauchamp
discussions with local experts, and available information regarding the distribution of vernal I
San Diego County (Bauder 1986).
Other materials consulted included soil maps from Bowman (1973), a 7.5' x 7.5', 500-scale (1'
color aerial photograph of the City (Aerial Fotobank, Inc., 6 February 1988), and a set of
scale (1"=4OO') blueline aerial orthophotos prepared by Fraser Engineering from aerial photc
dated September-October 1988. The blueline orthophotos were produced from a :;et of mylars
by the City of Carlsbad.
33 METHODS
A preliminary vegetation map was generated based on photo interpretation by circum:
vegetation communities (polygons) on the 400-scale blueline orthophotos using existing veg
1
I
II
I
32
maps from biological resources reports and observed distributions of vegetation types on the
orthophotos. Figure 3 illustrates the total area from which field-generated vegetation maps were
available. During this task, soils maps (Bowman 1973) and the MO-scale color aerial photograph were
consulted to help define vegetation boundaries. Reconnaissance level field surveys were conducted
by John Brown, Ph.D. (Dudek & Associates) and Sarah Flick (hlichael Brandman Associates) in areas
within the City where vegetation maps were incomplete, incompatible, or lacking. During the field
surveys, any sensitive plant or animal species encountered were noted and incorporated into the data
base, Terminology for vegetation communities employed are standardized community types as
adopted by SANDAG for their GIs efforts. These communities types follow Holland (1986) for the
most part, and are listed in Table 2.
The 23 completed 400-scale vegetation maps were photo-reduced and combined to produce a 1,OOO-
scale (l"=l,oOOq mylar of the preliminary vegetation map. The map was made available to private
and public agencies and landowners/deveIopers. Several planners, property owners, and developers
(e.g., Hoffman Planning Associates, Fieldstone Company, etc.) submitted more detailed or more
recent versions of the portion of the map that included their ownerships or planning areas. Each of
these submissions were subject to field review before incorporation into the final vegetation map.
During this review period, several other recent environmental documents became available (e.g., Lake
Calavera EIR, Rancho Santa Fe Road EIR, Carrillo Ranch EIIR, and the Aviara EIR), thus allowing
further fine-tuning of the preliminary vegetation and sensitive species maps.
A final set of 4OCl-scale blueline maps of the vegetation communities was produced incorporating all
, of the data received. Clear mylars of the vegetation polygons were made by tracing vegetation lines
from the 400-scale bluelines calibrated with the originals of thle City of Carlsbad orthotopo mylars.
Each polygon was labelled by a number code representing a specific community type (see Table 2).
The clear mylars with vegetation boundaries and reference points were submitted to SANDAG for
digitization. The vegetation plots produced by the SANDAG GIs system were submitted to team
biologists to check the accuracy of presentation and adherence: to the original orthophoto mapping.
Locations of sensitive plant and wildlife species were transcribed onto the 400-scale bluelines
orthophotos from existing biological documents. Sensitive species observed during field checking of
the vegetation maps also were recorded on the maps. Also, all publicly available information
regarding the distribution of the California gnatcatcher, as made available by Sweetwater
Environmental biologists, were incorporated into the map. Locations of sensitive species were
transferred onto the clear mylars of the vegetation communities and digitized by SANDAG
subsequent to digitization of the vegetation communities. Locations of most sensitive species were
identified by a point. However, large stands of specific sensitive plant species (e.g., California
adolphia and Del Mar manzanita) were identified by small polygons.
3.4 RESULTS
3.4.1 VEGETATION MAP
It is important to understand that the vegetation map was generated through photo interpretation
of blueline orthophotos and existing vegetation maps from EIRs and other available technical
documents. A limited amount of field work was conducted to field-check the accuracy of the maps.
There are areas of the (City that have not been surveyed beyond the photo interpretation provided
here. This methodology is adequate to develop a general vegetation map, but is not intended to
provide precise, site-specific vegetation information. Also, this methodology does not allow for
vegetation descriptions more precise than the plant community level. To satisfy the requirements of
the California Environmental Quality Act (CEQA), specific project areas will require focused field
33
LEGEND
SOURCE: SANDAG, August 1992
1
surveys to fine-tune the information provided here, characterize the general biological resou
the site, and provide site-specific analyses of sensitive resources.
Table 3 presents acreage by aggregated vegetation type for the City. More than 10,OOO acre
percent) of the City of Carlsbad were mapped as developed. Approximately 10,200 acres (41 pt
of the City still support natural habitat. Of the natural habitat, approximately 7,150 acI
percent) are comprised of native habitats. Although there is natural habitat distributed throi
the City, the largest areas of contiguous habitat generally are located in the eastern portion
City. With the exception of the lagoons, the western portion of the City is mostly develo
supports disturbed habitat.
I
1
i
1
I
1
I
8
8
I
1
1
1
i
1
I
I
I
Id
TABLE 3
ACREAGES BY AGGREGATED VEGETATION TYPES WITHIN THE
CARLSBAD HABITAT MANAGEMENT PLAN STUDY AREA
VegetationlLand Percent Percent
Cover Study Area of Total City of Total
Coastal Sage Scrub 3,018 10.6 2,503 10.0
Disturbed Coastal Sage 638 2.3 633 2.5
Chaparral 2,409 8.5 1,727 8.1 Non-Native Grassland & 2,619 9.2 2,449 9.8
Native Grassland 23 0.1 22 0.1
SaltiFreshwater Marsh 372 1.3 358 1.4
Scrub
Disturbed Grassland
Oak Woodland & Sycamore 709 2.5 618 2.5
Eucalyptus Woodland 305 1.1 302 1.2
Open Water 1,172 4.1 1,102 4.4
Alluvial Woodland
Disturbed Wetland 190 0.7 190 0.8
Disturbed Habitat, Active 4,986 17.3 4,545 18.2
Developed 1 1,987 42.3 10,191 410.9
Agriculture, Golf Course
TOTAL 28,337 100 24,940 100
Sensitive habitats present within the City include 3,149 acres (12.6 percent of the City) coast
scrub (including maritime succulent scrub and disturbed coastal sage scrub), 22 acres of
grassland, 358 acres of salt- and freshwater marsh, and 618 acres of oak and sycamore
woodlands. Chaparral, including southern mixed chaparral, chamise chaparral, southern m
chaparral, and coastal sage scrub/chaparral, occupies about 1,727 acres (8.1 percent of thc
Among the subtypes of chaparral, southern maritime chaparral is considered sensitive by lo(
regional resource agencies.
34
3.4.2 SENSITIVE SPECIES MAP
As with the vegetation map, it is important to note that the existing sensitive species information for
the City is limited. The information provided here comes from published information, existing EIRs
and other technical reports, and from communications with local biologists. While the data base is
reasonably good for plants and birds, information on sensitive reptiles and amphibians, for example,
is relatively poor -- even for previously surveyed areas -- because these species are often difficult to
detect. Other areas have not been surveyed for sensitive species at all. Therefore, the sensitive
species map can only be interpreted as evidence of positive findings. The absence of sensitive species
may indicate areas inadequately surveyed or not surveyed at all.
The results of the sensitive species mapping are presented in Figure 4. The most widespread sensitive
plant species within the City include California adolphia and ashy spike-moss, primarily in coastal sage
scrub; and wart-stemmed ceanothus, summer-holly, and Del hiar manzanita, primarily in southern
maritime chaparral. In drainages and riparian areas spiny rush is fairly common. Other sensitive
plants encountered less frequently include San Diego golden-star, western dichondra, Engelmann oak,
San Diego sagewort, San Diego marsh-elder, San Diego thorn-mint, and thread-leaved brodiaea.
The most widespread sensitive wildlife species present in the City is the federally-proposed
endangered California gnatcatcher. This species is resident nearly everywhere that coastal sage scrub
occurs. Figure 4 illustrates 113 gnatcatcher records, which includes both singletons and pairs. While
recording absolute numbers is useful for quantibng the presence and distribution of the species in
the City, it is important to note that numbers fluctuate from season to season and year to year, and
that not all areas of the City have been thoroughly surveyed. Dr. Pat Mock of Ogden Environmental
and Energy Services suggests that, based on a density estimate of one pair per 15 acres (which is an
average home range in the San Diego area) and approximately 2,500 acres of coastal sage scrub in
the City, Carlsbad could support as many as 166 pairs (P. Mock, pers. comm.). Thus, the number
of gnatcatchers in the City is at minimum 113, with perhaps as many as 166.
Other sensitive wildlife species encountered infrequently within the City include San Diego horned
lizard and orange-throated whiptail in coastal sage scrub; California least tern, Belding’s Savannah
sparrow, and light-footed clapper rail in estuaries and salt marshi areas; and least Bell’s vireo in willow
riparian habitat. Although not represented in the sensitive species map, the California brown pelican
and California least tern are common along the coast and in the lagoons in Carlsbad.
35
-_
#M am LBU
CAlEl cm
I lo Ev
cm
cm QRA cm BSSP mE
Cffi
I
Cm
- - .- ~
cm
------ ---
1
I
------
\- 4IRPrlRT ~
CMll
cv at$ Em
cvcv
td CACll 01
CAOW cm
89Idtive Pbntr
k AdoYlbdhb A# *cfwfcpn#a3 #m&m 4 ktrnldopdJlm k' hthmmtho?3who I hdkwmllbla Q mraro muni w ComaraslqPh$bdlLWsllbkD ct conthr0P)MAbgnlblis cv CaaMLhuJvmnvlur
dp &&mdvocdmtdo En Euphdb mima R FrrtITm bium
I) IW ham a .AnKu¶aaitur m u,aa ddme OI lkrcurmprlmmnll
Smndtive Anlmd8
\ \
* ~&Cmwo#M#
Bsp Eddmg'a Smnm 'm \ cm Cdifomb GndcDtchu am Clopprr Ral QtE Cdifornio lad Tan leu Lead W'r \hrso om h9.-hdod HrItptOll Lid sOHL Sm Dkqo Mcd Litad
I
I
8 \
,
,
Bio Logica 1 Preserve Ph
and Design App rd
/
/
1
\
\
RESOURCES AND HABITAT ANALYSIS -%d in support 4th ClTY OF WBAD HABITAT MANAGEMENT PLAN'
SECTION 4
BIOLOGICAL PRESERVE PLANNING AREA AND DESIGN APPROhACH
I
I
1
I
I
I
I
I
I
I
1
1
1
I
1
I
I
I
I
4.1 INTRODUCTION
A critical component of the HMP for the City of Carlsbad is the identification of areas withir
City limits that are suitable for a system of biological preserves, conservation, or management a
This section provides a discussion of the features used to identify biologically valuable areas. 7
factors then are incorporated in a quantitative methodology used to rank areas of the City in r(
to their biological value, rarity, and uniqueness. The results obtained from the ranking methot
form the basis for future decisions concerning habitat evaluation, acquisition, and imlplementatio
management of an HMP that are consistent with the City's General Plan, as well as state and fe
conservation planning efforts (e.g., NCCP and Habitat Conservation Plans [HCP]').
It is important to consider the conservation effort of the City in the context of other planning e
in San Diego County and the Southern California region (e.g., the MSCP, the North County M
and the NCCP for coastal sage scrub). Carlsbad, by itself, likely does not have enough remi
natural habitat to conserve any of the sensitive habitats or species of concern occurring in thc
in perpetuity (100- or 200-year survival with a 95 percent probability are common definitic
perpetuity used by conservation biologists). However, by developing an HMP that is consister
other conservation planning efforts, and through mutual cooperation with other jiurisdictions
region, Carlsbad can make a significant contribution to the conservation of native habitats and s
in Southern California. Within this context, therefore, the HMP does not purport to pro
comprehensive, stand alone preserve system for sensitive habitats and species. Rather, the p
of the HMP is to provide a program that contributes to overall conservation efforts and maintc
of functional ecosystems in Southern California.
4.2 PRESERVE DESIGN LITERATURE REVIEW
4.2.1 SIZE
Much of the literature on the design of nature preserves has focused on the physical charact
of the preserves, including their shape, size, and degree of isolation from other areas of
habitat. When the primary goal of a preserve system is to minimize the probability of extinc
its component species and maintain a functional ecosystem, larger preserves are more effecti
smaller ones. In isolated patches of habitat, it has been shown empirically and theoretically f
rate of species extinction is inversely related to patch size (Diamond 1975; Wright and Hubbe
Usher 1987; Soule 1991). The preserve size required to maintain various kinds of ecosys
poorly understood and requires much more scientific study. In general, the smaller the prese
greater the level of protection and hands-on management it will require to remain viable (Nos
There are several reasons why large preserves may be superior to small ones. Smaller p
necessarily support smaller populations of organisms. These small populations are more prc
larger ones to chance fluctuations in birth and death rates which, when extreme, can lead
extinction (Wilson and Willis 1975; Shaffer 1981; Jensen 1987). Small populations also
genetic variation as a consequence of genetic drift more rapidly than large populations (
1980; Lacy 1987). Loss of genetic variation can negatively affect a population of organisms
it results in higher levels of homozygosity, a condition in which a pair of genes at a particular
on a chromosome are alike. Homozygosity can be associated with poor growth, higher fret
36
of disease, and decreased survival during periods of stress (Soule and Simberloff 1986). Over the
longer term (from decades to thousands of years), depletion of genetic variation in small populations
can lead to an inability to adapt to changing environmental clonditions, and ultimately to population
extinction (Lacy 1987; Lande and Barrowclough 1987).
4.2.2 SHAPE
The shape of a preserve also can influence its ability to effectively conserve native species. At their
borders, nature preserves often will be subject to negative influences or "edge effects" from the
outside, including increased levels of predation and nest parasitism (e.g7 cowbirds laying eggs in vireo
nests), microclimatic changes (e.g., increased sunlight and temperature), and direct destruction of
. native vegetation and wildlife by human uses (Schonewald-(=lox and Bayless 1986, Yahner 1988).
Edge effects are strongest on habitat fragments that are small and irregularly shaped (Forman and
Godron 1981; Laurence and Yensen 1991). Several studies have considered the effect of increasing
perimeter relative to preserve size using a variety of quantitative measures (Faeth and Kane 1978;
Game 1980; Blouin and Conner 1985). Although the relationship between preserve shape and
immigration and emigration rates requires further investigation, it is generally true that preserves that
are circular in shape will have the least amount of edge for their size and thus will be least vulnerable
to edge effects. The extent and severity of edge effects ultimately will depend on the nature of the
habitat surrounding a preserve. In urban areas where immediate threats from "human-commensal"
species (e.g., pets and some pest species) exist at the edges of preserve boundaries (Murphy 1988;
Soule et ai. 1988), the ratio of edge to interior probably should be minimized whenever possible.
4.23 ISOLATIONIurILDLIF'E CORRIDORS
The degree of isolation of individual preserves also is an important design consideration, and in some
cases, may be at least as significant for the maintenance of regional biodiversity as overall preserve
size (Noss 1983). Both demographic (considering factors such as population size, reproduction,
mortality, emigration, and immigration) (Fahrig and Merriam 1985; Burkey 1989) and genetic
(Boeklen 1986, Boeklen and Bell 1987; Lacy 1987) models predict that higher levels of migration
between preserves will lead to lower probabilities of extinction. Only modest levels of migration (one
or two migrants per subpopulation per generation) may be required to mitigate the negative genetic
effects of population fragmentation (Lande and Barrowclough 1987). These models lead to the
design recommendation that isolated preserves be located as close together as possible in order to
facilitate exchange of individuals between subpopulations (Diamond 1975; Wilson and Willis 1975).
For species reluctant or unable to move through non-natural habitats (e.g., golf courses or agricultural
fields), the incorporation of habitat linkages (e.g., a wildlife corridor) into the design of a preserve
system is critical. Although empirical research on the optimal design for linkages is lacking, computer
simulations have been useful in identifying some of the basic factors that may influence habitat
linkage utility. Effective linkages must be wide enough to resist edge effects, contain the appropriate
habitat(s) of the key species expected to travel through them or use them for dispersal, possess
adequate cover to prevent excessive predation on migrants or dispersers, and contain as few turns or
other barriers to movement or dispersal as is feasible (Soule and Gilpin 1991). In addition, networks
of several habitat linkages probably provide a better system for migration and dispersal than single
connections because alternative routes are available (Forman and Godron 1981; Noss 1987).
4.2.4 BUFFERS AND DISTANCE SETBACKS
In order to maintain the integrity of biological resources adjacent to development or other land uses
generally considered incompatible with biological resource areas (e.g., active recreation areas that
receive heavy human use), the interface between natural open space and development (sometimes
37
called the naturalhrban interface) must include an appropriate buffer area. Strictly define
"buffer" includes the area between the open space boundary and the boundary of a SI
development or land use. It is assumed that habitat within the buffer area will be degrad
human-caused disturbance and, thus, the area should not be considered part of the "preseme
Various approaches have been taken to quantify disturbance from development and s
appropriate buffers for biological resources in Southern California (Scott 1992; Sauvajot 1992;
and Rotenberry 1992). It is clear that no single approach or specific buffer distance will satis
buffer needs for different resources under different levels of pressure from development. I
Diego, for example, a table of distance setbacks between land-use types and biological resourcc
developed by Pacific Southwest Biological Services (PSBS ). A comparable set of guidelines ha:
developed for the San Diego County Resource Protection Ordinance (RPO). Howeve
recommended buffer distances deviate greatly between the two lists. Dudek & Associatt
developed a set of buffer values that represents a compromise between the PSBS and
recommendations. The ranges of buffers are meant to provide a general guideline and a
intended to act as rigid standards. Also, these guidelines derive from qualitative inpui
experienced field biologists and do not come from scientific field studies. Unfortunately, thou
tested and validated field data do not exist at this time, although ongoing studies shlould providt
data on the question of buffers in the next two to four years (Scott 1992; Sauvajot 1992).
specific naturalhrban interface should be evaluated independently considering the guidelines a
biological sensitivity of the habitat and wildlife species adjacent to development.
Flexibility in setback distance is necessary to reasonably and logically accommodate the varying I
or sensitivity of resources within natural open space adjacent to proposed land uses. For ex
buffer width should be greater between high quality coastal sage scrub and residences, becam
quality coastal sage scrub is likely to support more sensitive species. Narrow riparian corrido
require wider buffers than broad riparian corridors in order to allow comparable imobstructec
space to facilitate wildlife use and movement. Topographic barriers, such as canyons, rock ou
steep slopes, and elevational differences, may render prescribed buffer distances inapprc
Finally, simple linear calculations or formulas for buffers may be inappropriate when develc
patterns create variations in the contour of the natural urban interface. For example, a develc
with an undulating boundary or comers at acute angles (i.e., less than 90 degrees) will result i
space peninsulas which share more border with the development than a development with
angles. In this situation, the buffer would have to be greater to compensate for the greater in
area.
Ideally, no recreational activities or active land uses would be permitted within buffer areas. I
buffer areas, however, passive recreation may be an acceptable use. Whether recreational ac
are acceptable in certain buffers will depend on the characteristics of the buffer, the sensitiviq
natural area, and the planned recreational use. Hiking and equestrian trails, for example, wc
appropriate in many buffer areas while off-road vehicles would not. While natural habi
designated as open space is the preferred buffer, cut slopes, fills, brush management zones, a
breaks may be acceptable depending on the type of habitat.
Some general suggestions for specific habitat types, based on the RPO staindards anc
recommendations, are provided below. It is important to keep in mind that these guidelin
provide minimum buffer sizes, that each case must be evaluated independently, and that there
scientific data or even agreement among biologists regarding the appropriate buf €er distance:
given setting.
I
I
I
I
I
I
8
I
1
I
I
I
I
I
1
I
I
I
I 38
Coastal Sage Scrub and Chaparral
In general, scrub communities such as coastal sage scrub and chaparral should be provided with at
least a 100-foot buffer where interfacing with residences and a 50 to 75-foot buffer where interfacing
with commercial and industrial development, active park uses., and schools. For coastal sage scrub
and chaparral communities occupied by sensitive plants, the buffers are the same as cited above,
because plants are unlikely to be affected by noise and light impacts associated with these types of
developments. The greatest risk to sensitive plants is from trampling by human foot traffic, mountain
bikes, and motorized off-road vehicles. For coastal sage scrub occupied by California gnatcatchers
and other sage scrub avian species, a buffer of at least 200 feet is recommended at interfaces between
residential and commercial development and the occupied habitat. Occupied habitat can be defined
as the native vegetational community that is within the territory of a single pair of birds.
Grasslands
For annual (non-native) and perennial (native) grasslands, buffers of at least 20 to 50 feet are
recommended between the habitat and proposed residential and commercial development. Again,
the precise buffer distance should be determined by the quality and quantity of the specific grassland
habitat. For some annual grasslands, a buffer may be inappropriate or unnecessary under certain
conditions; for instance, where the grassland does not represent sensitive plant or wildlife habitat or
does not serve a corridor function.
Mulefat Scrub
As a component of the riparian system, mulefat scrub should be provided with a buffer that is 50 to
100 feet wide, depending on the quality of the habitat and its function within the matrix of the
surrounding vegetation (e.g., corridor, foraging habitat). The County RPO specifies that 25 feet is
the minimum buffer far riparian habitat; PSBS suggests 100 feet for most interfaces between mulefat
scrub and development.
Southern Willow ScruWRiDarian Habitat
Throughout Southern California, southern willow scrubhiparia n woodlands are recognized as highly
productive habitats. The structural diversity of the woodlands i3nd the availability of water and food
resources combine to support a rich diversity and abundance of wildlife species. According to the
County RPO, the "appropriate width of a buffer adjacent to an area of riparian habitat varies
depending upon specific site conditions." The RPO recommends a minimum buffer of 25 feet, but
indicates that buffers up to 200 feet may be required in some instances to maintain the biological
viability of the habitat. To avoid disturbance to resident wildlife, it is recommended that buffers
between riparian woodlands and commercial and residential dewelopment be at least 100 feet wide.
Where riparian woodlands are occupied by least Bell's vireo, buffers should be based, to a large
extent, on the width of the riparian corridor. The USFWS, for example, has indicated that the
average width of vireo-occupied habitat on the San Luis Rey River is approximately 800 feet.
Assuming that the 8W-foot corridor is appropriate for vireo habitat, buffers should be large enough
to accommodate this width. Hence, if the riparian corridor is 200 feet in width, buffers of at least
300 feet on each side are appropriate (Le., 300 feet + 200 feet -t- 300 feet = 800 feet). The RPO
suggests 200 feet and PSBS suggests 500 feet as buffers to vireo-inhabited riparian areas.
Oak Woodland
Oak woodlands support considerably more wildlife species than the scrub and grassland communities
discussed above. More than 300 vertebrate species are known to utilize oak-dominated woodlands
39
in California for reproduction, overwintering, and during migration (Block et al. 1990). IF
disturbances to oak woodlands are particularly acute because these woodlands generally are
accessed by the public and thus are adversely affected by legitimate recreation activities (i.e., k
mountain bikes, picnicking, etc.) as well as by illegitimate uses (trash dumping, vandalism, itii
worker camps, shooting, etc.). Preliminary scientific information concerning urban effects c
woodlands adjacent to residential housing indicates a decline in bird species diversity resultin1
the influx of people and human-commensal species such starlings and house sparrows (Scott
The County RPO sets minimum buffer for oak woodlands at 25 feet from the dripline
individual tree or from the edge of an oak woodland. However, to reduce disturblance to wild
is recommended that buffers between oak woodlands and development be at least 50 to 10
wide. Furthermore, oak woodlands designated as part of a biological preserve either should I.
limits to the public or receive controlled numbers of visitors engaging in passive recreation aci
(e.g., nature hikes or bird watching restricted to established trails).
4.2.5 OTHER CONSIDERATIONS
In addition to the physical aspects of preserve design, several authors have discussed biological
criteria, including where preserves ideally should be located, what types of communities and :
they should contain, and how they ultimately should be managed. Biological criteria employed
designs for preserves include the diversity, rarity, uniqueness, representativeness of the s
habitats, and natural communities contained in potential preserve areas (Tubbs anld Blackwooc
Goldsmith 1975). Other studies have emphasized that the threat of human interference, avai
of land containing undisturbed natural habitat, and ease of management, also should be corn
in the location of preserves (Tans 1974; Gelbach 1975; Wright 1977). Margules and Usher
stressed the benefits of using a quantitative scheme to assess the relative suitability of si
inclusion in preserve systems. Some of the most successful methodologies have been tho:
incorporate information both on the biological value and manageability of natural areas, and (
procedures for differentially weighting chosen criteria (Duever and Noss 1990).
Fundamental differences between ecosystems necessitate that the physical and biological as€
preserve design must be addressed independently for each preserve system. However, results
studies provide useful general guidelines, especially with regard to which physical variab
.important for long-term viability of preserves and how biological resources contained in dl
potential preserve sites might be compared objectively.
43
A "landscape" approach is used to identify critical biological resource areas in Carlsbad
approach, which considers the existing biological diversitywithin the City, is based upon the fo
goals:
1
I
1
I
I
I
E
I
1
I
I
I
I
I
I
I
I
I
PRESERVE DESTGN RATIONALE AND APPROACH
e The primary goal is to conserve large landscape-sized features in an intercoi
system of self-sustaining (Le., independent) ecological units. Although mana
will be an important component of the HMP, preserved areas should remaii
without extreme intervention measures, including extensive vegetative restor I translocation of species.
e A secondary goal is to conserve areas known to support viable populations
and federally listed endangered and threatened species and their habitat:
species and habitats likely to become threatened, endangered, or rare in the
and other species or habitats of concern on the state, regional, or local leve,
40
The methodology used for the biological resource analysis was as follows:
0 An attempt was made to broadly categorize areas as to their overall biological value
and sensitivity rather than to plan for a particular subset of species. Because limited
time and money precluded focused, detailed biological surveys throughout the City,
general habitat and vegetation information, specific information from previous
biological surveys (e.g., from EIRs), consultation of resource data bases (e.g., CNDDB
and CNPS), and interviews with local biological experts served as the information base
for identifying the critical resource areas.
Preserve design criteria and evaluation follow from general conservation principles
and biogeography theory, as discussed above.
0
4.4 PRESERVE DESIGN METH ODOLOGY
The methodology for identifylng potentia1 preserve areas and developing a ranking system for
components of the preserve system is described in this section. This approach serves as a guideline
for identifymg potentia1 preserve units. The approach was not meant to assign absolute biological
values to each of the units or areas considered for preservation, but to provide relative values for
comparisons among areas. For this reason, while there is a solid scientific foundation for the preserve
design features chosen, the point values assigned in the ranking system were somewhat arbitrary. The
main goal was to develop a ranking system that auld be applied objectively and fairly to each of the
areas considered for preservation. This approach represents an amalgamation of approaches used
in other settings (e.g., Duever and Noss 1990, ERCE 1991), but tailored to the needs of the City of
Carlsbad as allowed by the available funds and time to develop the information.
4.4.1 FOCUSED PUNNING AREAS
As an initial step, undeveloped areas within the City of Carlsbad were divided into seven or eight
focused planning areas (FPAs). For purposes of our analyses, "undeveloped areas" were defined in
two alternative ways: ~(l) all areas that presently are mostly vacant (Le., without permanent physical
structures) and do not have an approved tentative map (Figure 5); and (2) all areas that presently
are vacant, including those with an approved tentative map (Figure 6). The reason for two different
sets of FPAs is that areas with approved tentative maps may yet be constrained from development
if the California gnatcatcher is federally listed as endangered. Under Section 9 of the federal ESA,
any lands with gnatcatchers would be protected until issuance of a Section 1O(a) incidental take
permit or a permit issued pursuant to Section 7 (in the case of a federal action linked to the project).
Lands with gnatcatchers thus would be potential preserve areas even if they had an approved
tentative map. The first alternative (Le., the pre-gnatcatcher listing scenario) resulted in eight distinct FTAS. The second alternative @e., the post-gnatcatcher listing scenario) resulted in seven distinct
FPAS.
The FPAS were delineated by circumscribing large, continuous areas of the relatively undeveloped
land. Major existing roadways (e.g., El Camino Real and Pallomar Airport Road) and existing or
proposed development (under alternative 1) provided relatively natural and intuitive boundaries for
the FPAs.
Using GIs, the entire City of Carlsbad and some adjacent areas in San Marcos and Encinitas were
overlain with a grid comprised of cells 1,OOO feet on each side. Each cell contains 22.9 acres. The
grid approach was used because it provides a neutral, objective method for dividing up the focused
planning areas into analyzable units. Public and private property boundaries, proposed land uses, and
circulation elements, which likely will affect the configuration of the preserves, were explicitly
41
excluded from this analysis in order to focus only on biological factors. Also, a grid system is
more amenable to computer analysis using the GIS data base.
"le GIS output from SANDAG was used to generate an overall rating of two features, habitat
(HV) and habitat sensitivity (HS), utilizing separate layers with vegetation community distrib
and sensitive species. (Vegetation communities and habitat are treated as synonynious here be
each native or introduced community, including introduced eucalyptus, provides habitat for a \
of species). After each of the cells was rated on HV and HS, they were ranked for their impoi
for inclusion in a preserve system. It was assumed that sets of adjacent cells with high rankings
become the building blocks for the preserve system.
Evaluation of HV was based on: (1) the amount of natural habitat in the cell, including coasta
scrub, chaparral, native and non-native grassland, riparian scrub, oak woodland, eucalyptus woo
freshwater marsh, salt marsh, disturbed wetland, and open water; (2) the number of different h
represented; (3) the connectivity of natural habitats in the cell with habitats of the same type i
sharing a side with the focal cell (i.e., excluding cells that connect on the corners); ai
vulnerability and manageability, based on land use in the adjacent cells. Each cell was rated fc
feature and given a total HV rating, with a maximum of 100 points.
Evaluation of HS of each cell was based on: (1) the presence and amount of sensitive habit
the diversity of sensitive habitats; (3) the presence and abundance of the California gnatcatch
coastal sage scrub; (4) numbers of sensitive plant species; and (5) numbers of sensitive c
species. Each cell was rated for each feature and given an HS rating, with a maxirnum of 100
A separate category for presence of the California gnatcatcher was added because the species il
to be federally listed as endangered, and thus will be a key environmental issue for the pr
system.
I
I
I
I
E
1
i
1
I
1
1
I
1
1
1
I
I
1 4.4.2 PRESERW FEATURE DEFINITIONS AND RATINGS -- HABITAT VALUE
Habitat value refers to the general biological value of each of the cells based upon the pres(
natural vegetation. The presence of sensitive habitats, endangered or threatened species, o
sensitive biological resources were not considered or given extra weight for the HV rating. TI
of rating cells for HV simply was to identify those areas that have the best remaining
vegetation and habitat in Carlsbad, and those areas that will provide the foundation for a
biological preserve system.
Amount of Natural VegetatiodHabitat Areas
This feature addresses the amount oE natural communities or habitat within a cell. The amc
natural habitat is an important factor for the contribution of a cell to the overall biological T
of the preserve system. The goal is to assemble several contiguous cells, each with substantial
habitat, into a cohesive, self-sustaining ecological preserve area. Also, cells with large amo
natural habitat are likely to presently contain more species diversity than cells with less habit
sustain biological diversity (community and species diversity) over long periods of time (Albei
1992). "Natural communities" encompass coastal sage scrub (all subassociations), chaparral
grassland, riparian scrub, disturbed wetland, oak woodland, freshwater marsh, salt marsh, ope]
and non-native associations including eucalyptus woodland and non-native grassland. 1
42
Criteria and points for amount of habitat were as follows:
Criteria Points
> 22 acres 25
17 to 22 acres 20
11 to 16 acres 15
4 to 10 acres 10
e 4 acres 0
Community/Habitat Diversity
This feature addresses the number of different natural vegetation communities or habitat types within
a cell. The assumption was that cells with several different communities will have relatively more
biological value than cells with little diversity. This assumption, however, is not always correct or
useful. In the case of coastal sage scrub or freshwater marsh, for example, a cell with a single
sensitive community may have extremely high biological value. Such cells were considered on the HS
rating to ensure that they were not undervalued in the final ranking of the cells. For the purpose
of assessing community diversity, the vegetation and habitat types listed above were used. Community
types that have subassociations (e-g., coastal sage scrub and chaparral) were considered as a single
community type. Unfortunately species diversity within a community could not be considered for the
analysis because there are too little current field data. Detailed field investigations would be required
to address species diversity.
Criteria and points for natural communityhabitat diversity were as follows:
Criteria Points
> 5 communities 25
4 or 5 communities 20
2 or 3 communities 15
1 community 10
0 natural communities 0
Connectivity of Cell
This feature addresses whether or not a cell has meaningful biological connectivity to adjacent cells.
An adjacent cell was defined as a cell that shares a side with thie focal cell. Cells that connect at the
comers of the focal cell were not included in this analysis because the connection is at only a single
point. Thus, each focal cell is adjacent to four other cells. Meaningful biological connectivity was
defined as adjacent cells containing the same community type. For example, if coastal sage scrub
occurs in adjacent cells, those cells are considered to have meaningful biological connectivity because
the species within those cells would comprise a single population, even though the habitat may not
be strictly continuous. Furthermore, the "continuous" habitat could serve as a habitat linkage to
43
other, disjunct cells. The connectivity feature is important for assembling several biologically va
units into a cohesive preserve area. The degree or value of connectivity was determined b;
many sides of the focal cell connect with adjacent cells having the same habitat. A cell that COI
to three or four other cells clearly is more valuable as a preserve unit than a cell with on1
connection; Le., an edge unit (although the edge unit may serve as an effective buffer).
A difficulty that arises with this feature, as defined, is that focal cells bordered by cells with very
patches of habitat would be given high scores even though the biological "connection" value t
habitats would be relatively low, particularly with habitats such as coastal sage scrub, chaparra
non-native grassland. These habitats must be at least a few acres in size to have much loq
biological value. Other habitats such as riparian woodland, scrub, marsh habitats, arid open watc
have relatively high value even if they comprise only a few acres. To offset the problem of in
connectivity scores, adjacent celIs had to contain at least one acre of coastal sage scrub, chaj
or non-native grassland to be scored as an adjacent cell with the same habitat.
The criteria and points for connectivity were as follows:
I
i u
I
i
1
1 3 sides connecting to same habitat 20
8
1 0 sides connecting to same habitat 0
I
1
I
I
I
I
1
8
I
1
Criteria Points
4 sides connecting to same habitat 25
2 sides connecting to same habitat 15
10 1 side connecting to same habitat
Land Uses Adiacent to Cell
This feature addresses whether land uses in adjacent cells are compatible with the biological v
and integrity of the focal cell. The assumption was that residential, commercial, and in(
development are existing land uses relatively incompatible with the biological viatdity of a fo
because of the potential for human disturbance, including active recreation (e.g., off-road v
or mountain bikes), predation by pets, trash dumping, and chemical spills. Ultimately edges
preserve areas will border adjacent land uses that likely will pose some threal to the pre
However, the overall management plan should include measures to minimize adverse impacts
preserves by adjacent land uses (e.g., the development of buffers, anti-pet Fencing, ant
restrictions). For the purpose of rating each cell, cells surrounded by natural habitats of ai
received the highest rating, and those surrounded by developrrient or disturbed habitat receiT
lowest rating. By definition, an adjacent cell with at least 20 acres of natural habitat was coni
undisturbed.
44
The criteria and points for adjacent land uses were as follows:
Criteria Points
At least 20 acres natural 25
habitat on 4 sides
At least 20 acres natural
habitat on 3 sides
At least 20 acres natural
habitat on 2 sides
At least 20 acres natural
habitat on 1 side
Less than 20 acres natural
habitat on any side
20
15
10
0
4.43 PRESERVE FEATURE DEFINITIONS AND RATINGS -- HABITAT SENSITIVITY
The habitat sensitivity rating considers the presence of sensitive vegetation communities or habitat,
such as coastal sage scrub or wetlands, and the presence, or potential presence based on habitat, of
sensitive wildlife or plants species. Because the proposed endangered California gnatcatcher and
coastal sage scrub is ai key issue for development of the HMP, and several other federal candidate
species occupy coastal sage scrub, gnatcatchers and coastal sage scrub were given a separate category.
Amount of Sensitive Habitat
This feature addresses the question of how much, if any, sensitive habitat a cell contains. Sensitive
habitat includes coastal sage scrub (including all subassociatioris), southern maritime chaparral, oak
woodland, riparian scrub, freshwater marsh, salt marsh, open water, and native grassland.
The criteria and points for amount of sensitive habitat were as follows:
Criteria Points
> 22 acres 20
15 to 22 acres 15
9 to 14 acres 10
2 to 8 acres 5
e 2 acres 0
Five points were added if the cell supports any sensitive habitat other than coastal sage scrub. (This
accounts for the problem that some sensitive habitats often cover small areas, such as wetlands,
riparian woodland, or native grassland.)
45
Diversitv of Sensitive Habitats
This feature addresses the diversity of sensitive habitats within a cell. The assumiption was th
greater the diversity of sensitive habitats within a cell, the greater its biological value and the
valuable it would be for acquisition.
The criteria and points for the diversity of sensitive habitats were as follows:
I
i
I
1
I
1
1
I
I
I
1
I
1
I
1
Criteria Points
4 or more sensitive habitats 20
3 sensitive habitats 15 1 2 sensitive habitats 10
1 sensitive habitat 5
0 sensitive habitats 0 I California Gnatcatcher
This feature addresses the presence of the California gnatcatcher or its habitat within a cell. Bi
the gnatcatcher is likely to be federally listed as endangered, preservation of gnatcatcher ha1
a high priority for the HMP. The highest ratings were given to cells that are known to si
gnatcatchers and have the highest quality gnatcatcher habitat. Areas with coastal sage scrub,
documented gnatcatchers received a lower rating.
The criteria and points for gnatcatcher habitat were as follows:
1
Criteria Points
2 gnatcatcher pairs 20
1 gnatcatcher pair 15
At least 15 acres of coastal 5
sage scrub, but no documented
gnatcatcher pairs
Less than 15 acres of coastal
sage scrub or no potential habitat
0
Sensitive Plants
This feature addresses whether the cell supports plant species that are recognized as sensitk
or unique by the USFWS, CDFG, CNPS, or other regional or local organizatiom.
The criteria and points for sensitive plants were as follows: 1
46
Criteria Points
20 Documented presence of state or
federal endangered or threatened
plant species
Presence of federal candidate 15
species
Presence of two or more CNPS
or locally-recognized Sensitive
species
10
Presence of one CNPS or locally-
No documented presence of 0
5
recognized sensitive species
sensitive species
Sensitive Wildlife
This feature addresses the presence of sensitive wildlife, or lhabitat with potential for supporting
sensitive wildlife, within a cell. Sensitive wildlife was defined as both vertebrates and invertebrates
that have state or federal endangered or threatened status, federal candidate species, state Species
of Special Concern, or species considered sensitive, rare, or unique by regional or local agencies or
organizations. Thus, any sensitive mammals, reptiles, amphibians, birds, or insects were considered
here. Sensitive habitats that provides breeding, foraging, or refuge opportunities for sensitive wildlife
also were considered.
Criteria and points for sensitive wildlife were as follows:
Criteria Points
Documented presence of federal 20
or state endangered or threatened
species
Presence of federal candidate 15
or state Species of Special Concern
Presence of at least 15 acres of
sensitive habitat
5
4.5 RESULTS -- HABITAT VALUE
As described in detail above, the analysis of habitat value (HV) for each of the cells was based on
the amount of natural vegetation within a cell, the diversity of vegetation communities, the
connectivity of the ceIls, and the adjacent land use. For the purpose of analysis, the grid was laid
over a study area consisting of the entire City of Carbbad and some adjacent areas to the south and
east that contain natural open space (i.e., Encinitas and San Marcos), yielding a total of 1,237 cells
(a total of 28,327 acres). A total of 1,179 cells (26,999 acres) occur either in part or whole in the
Carlsbad City limits. Because the grid was placed in an arbitrary position over the study area, the
47
perimeter cells usually fall partly inside and outside of the City limits. Of the 1,237 cells, 97
(79 percent) scored at least 10 points. This accounts for 22,373 acres of the 28,337 acres in the
area (see Table 3). Cells scoring no points are located in the most urbanized areas of Ca
Table 4 shows the frequency distributions for each of the features comprising the HV score.
of the features is discussed below.
4.5.1 AMOUNT OF NATURAL HABITAT
The frequency distribution for the amount feature illustrated in Table 4 demonstrates that the
for the feature are well distributed. There were 336 cells (34 percent) receiving scores of
better (Le., cells with 17 acres or more). There were 480 cells (49 percent) receiving scores o
less (i.e-, 10 or fewer acres).
4.5.2 HABITAT DIVERSITY
For the diversity of vegetation communities, the scores for cells also were well distributed. Hc
the scores tended to fall more in the middle values than with the amount feature. Only fi~
received scores of 25 (> 5 different communities) while only 11 cells received scores of 0 (no 1
communities). However, 134 cells received scores of 20 or better (4 or more different commu
I
I
1
1
1
1
1
t TABLE 4
FREQUENCY DISTRIBUTION FOR HABITAT VALUE FEATURES
Habitat Value Features
I
1
1
I
I
1
Assigned Amount Diversity Connectivity Adjacent
Value Land Use
0 244* 11 73 450
10 236 302 50 272
15 162 53 1 147 165
20 180 129 264 62
25 156 5 444 29
I TOTAL 978 978 978 978
1 * The number or frequency of celIs assigned a particular value
I
i
1 48
4.53 HABITAT CONNECIlVITY
Cells tended to fall at the high end of values for the connectivity feature; 444 cells (45 percent)
received scores of 25. The reason for this result is because the threshold for inclusion as a connected
adjacent cell was fairly liberal. If a cell had any habitat that was the same as the focal cell, except
for coastal sage scrub, chaparral, or non-native grassland, it was scored as a connected adjacent cell.
This liberal criterion was used because even very small patches of certain vegetation communities,
such as riparian woodland, salt and freshwater marsh, or native grassland, have high biological value
and are valuable if proximate to the same habitat in an adjacent cell. For coastal sage scrub,
chaparral, and non-native grassland, the threshold for scoring as an adjacent cell was that it must
contain at least one acre of the same vegetation community. The rationale for this contingency is
that these communities require somewhat larger areas to provide viable habitat for wildlife and plant
species. The one acre requirement thus eliminates slivers of extremely small patches of vegetation
that carry relatively little biological value.
4.5.4 ADJACENT LAND USE
Adjacent land use scores provided almost a mirror image of the distribution for connectivity; 722 cells
(74 percent) scored 0 or 10 and only 256 cells (26 percent) scored 15 or more. In other words,
relatively few cells have adjacent cells with 20 or more acres on at least two sides.
4.5.5 COMPOSITE HABITAT VALUE
Table 5 shows the composite HV frequency distribution. This distribution reflects the total score of
each of the cells achieved by adding the scores for each of the FW features discussed above. No cells
had a perfect score of 100. The overall distribution approximate:s a normal (bell-shaped) distribution,
with most of the scores falling in the middle of the distribution. There were, however, a
disproportionate number of scores, assuming a normal distribution, with a score of only 10. These
cells are located in the more urbanized areas of Carlsbad and tend not to occur in the FPAs. Overall,
228 cells (23 percent) scored 75 points or better, 382 cells (39 percent) scored 50 to 70 points, 269
cells (27 percent) scored 25 to 45 points, and 98 cells (10 percent) scored 20 points or fewer.
The spatial distribution of HV scores is illustrated in Figure 7. 'The map illustrates that cells with the
highest scores tend ta cluster together. Clustering here is defined as a focal cell having a direct
connection with another cell either by sharing a side or connecting on a corner. Only four of the 228
cells scoring 75 points or more were not in some way directly connected (including a connection on
a comer) to an adjacent cell scoring at least 75 points. In part, this is because connectivity was a
factor in the HV score, but it also reflects the fact that Carlsbad still has relatively large, contiguous
areas with high habitat value. Approximately 5,100 acres of the best habitat in Carlsbad generally
occurs together. These clusters range in size from about 850 acres in the southeast part of the City
to about 68 acres in the northern part. Cells that received scores between 50 and 70 tend to
surround the highest scoring clusters. Cells with lower scores tend to be around the perimeter of the
higher scoring clusters and in the areas outside of the FPAs. Only five of 96 cells scoring 20 points
or fewer are completely surrounded by cells scoring at least 25 points.
Figure 7 shows that the FPAs do indeed capture most of the best remaining habitat in Carlsbad.
49
I
i
1
I
I
1
1
I
i
1
1
1
1
1
I
1
1
I
-
Carisbad Habitat Management P
Habitat Value M
m
TABLE 5
COMPOSITE HABITAT VALUE
Value Frequency h7alue Frequency
10 57 55 84
15 7 60 77
20 34 65 70
25 44 70 74
30 59 75 80
35 40 810 63
40 67 8.5 53
45 59 93 28
50 77 9.5 4
TOTAL 977
4.6 DISCUSSION -- HABITAT VALUE
Decisions concerning habitat acquisition and implementation of the preserve and corridor system will
in large part rest on the habitat value of the parcels considered for acquisition, as well as upon
acquirability, economic, and land use factors. Any strategy, however, will allow for acquisition of only
a portion of the remaining natural habitat within the City. Thle optimum strategy is to acquire and
conserve the best remaining core areas and link them by multiple habitat corridors.
The results of the HV analysis indicate that Carlsbad should have reasonably good flexibility in
establishing an interconnected preserve system, because there are six or seven core areas with
generally high habitat value. Some subset of three or four of these areas, with corridor linkages
connecting all or part of the system, would be desirable. Most important, it appears that Carlsbad
at least has the raw biological material from which to assemble a functional preserve system.
While an analysis of general HV is an important aspect of delineating potential preseme areas,
information about general species richness and the presence of sensitive habitat and species also is
important. The HV analysis provides a starting point from which to consider the other factors
important for designing feasible and functional preserves. The next section considers the presence
and distribution of sensitive habitat and species.
4,7 RESULTS -- HABITAT SENSITIVITY
The analysis of habitat sensitivity (HS) for each cell was based on the amount of sensitive habitat(s)
within the cell, the presence of, or habitat for, the California gnatcatcher, the presence of sensitive
plants, and the presence of sensitive wildlife species. Sensitive habitats included coastal sage scrub
(including all subassociations), southern maritime chaparral, oak: woodland, riparian scrub, freshwater
marsh, salt marsh, open water, and native grassland.
50
4.7.1 AMOUNT OF SENSITlVE HABITAT
The frequency distribution for the amount of sensitive habitat within a cell is well distributed I
6). Most cells scored relatively low, but 268 cells (27 percent) received 15 or 20 points. The
acre cells contain at least 15 acres of sensitive habitat. This kind of distribution was expected bc
sensitive habitats, by definition, are more rare and comprise fewer total acres thlan other ha
This is especially true for riparian, marsh, and native grassland habitats.
4.7.2 SENSITIVE HABITAT DIVERSITY
The frequency distribution for the diversity of sensitive habitats is similar to that for the ama
sensitive habitat. Most cells received a low score, but 129 cells (13 percent) received 15 or 20
That is, these cells contain three or more different sensitive habitats within the same cell.
8
R
1
I
I
II TABLE 6
FREQUENCY DISTRIBUTION FOR HABITAT SENSITIVITY FEATURES
Habitat Sensitivity Features
1
II
i
1
1
I
1
1
I
1
B
I
Size Diversity Gnatcatcher Sensitive Sensitive Assigned Value Presence Plants Wildlife
0 267 164 833 820 742
5 218 457 65 105 150
10 225 228 NA 34 NA
15 133 % 66 9 5
20 135 33 14 10 81
TOTAL. 978 978 978 978 978
1 4.73 CALIFORNIA GNATCATCHER
Table 6 and Figure 4 show the most recent publicly available information concerning the dist
of California gnatcatchers in the City of Carlsbad. (It is important to note that all not all
the City have been surveyed for gnatcatchers nor were all data available €or public review at 1
of this writing.) Cells scoring 20 points had two gnatcatcher pairs, cells scoring 15 points 1
pair, and cells scoring 5 points had no documented pairs, but contained at least 15 acres of
sage scrub, and thus have at least some potential to support gnatcatchers. Figure 4 ihstra
the gnatcatcher distribution tends to cluster similarly to cells scoring high in habitat value (set
51
7), with the exception of 17 pairs in disjunct or isolated cells (i.e., cells having no direct connection
with another cell either containing gnatcatchers or having at lleast 15 acres of coastal sage scrub).
4.7.4 SENSITn7E PLANTS
Table 6 shows the distribution of cells containing plants witlh three levels of sensitivity: state or
federally threatened or endangered, federal candidates, and CNPS or locally-recognized sensitive
species. Only 10 cells contained plants with the most sensitive status and only nine cells contained
federal candidate species. Plants with CNPS or local status were found in 139 cells.
4.7.5 SENSITTVE WILDLIFE
The California gnatcatcher is a proposed endangered species. However, because it is likely to be
listed as endangered by early 1993, it was treated in the analysis as federally endangered. The
gnatcatcher was also included under sensitive wildlife, in addition to its own category, because of its
high profile in the HMP process. In essence, it receives more than double weighting in this analysis
because any cells containing a single gnatcatcher pair receives 20 points. Table 6 shows that 81 cells
received 20 points; 80 of which contain gnatcatchers and one of which contains a least Bell’s vireo.
Only five cells contain federal candidate species, including the San Diego horned lizard and orange-
throated whiptail (see Figure 4). Because the data base for sensitive wildlife is primarily comprised
of biological surveys conducted for EIb9 there is a paucity of information on sensitive wildlife
compared to the amount of information available on the presence of sensitive habitats and
gnatcatchers. The absence of other sensitive species from cells may only reflect a lack of focused
surveys for these species. Prior to acquisition of habitat for the preserves, additional focused surveys
for sensitive wildlife will be necessary if this factor is to be an important acquisition criterion.
4.7.6 COMPOSITE HABITAT SENSITMTY
Table 7 shows the composite frequency distribution for HS resulting from adding the feature scores
for each cell. The scores are well distributed, but skewed toward the lower scores. This was expected
due to the rarity and uniqueness of the biological resources considered sensitive. Only eight cells (< 1
percent) scored 75 points or more, 74 cells (7 percent) scored 50 to 70 points, 284 cells (29 percent)
scored 25 to 45 points, and 612 cells (62 percent) scored 20 points or fewer.
Cells with higher HS scores tend to be clustered in the FPAs (Figure 8). Only 14 of 82 cells (17
percent) that scored mare than 50 points are completely isolated from other cells scoring at least 50
points. Twelve cells scoring at least 50 points are connected only at the corner with another cell
scoring at least 50 points. In other words, of the 82 cells scoring at least 50 points, 56 (68 percent)
share at least a side with another cell scoring 50 or more ]points. As would be expected, the
distribution of cells with high HS scores generally matches the distribution of cells with high HV
scores. However, because the HS score represents more rare and unique biological resources, the
absolute scores for HS are generally lower than HV scores on a cell by cell comparison. Only two
cells that scored at least 75 on HS scored lower than 75 on HV.
52
1
I
I
1
I
U
I
I
I
1
I
1
II
I
8
I
1
I
i
-
Carlsbad Habitat Management P
Habitat Sensithrity M
TABLE 7
COMPOSITE HABITAT SENSI[TIVITY
Value Frequency Value Frequency
0 1 43 45 26
5 1 08 50 19
10 164 55 19
15 95 60 17
20 102 65 9.
25 68 70 10
30 76 75 3
35 70 75 3
40 44 80 3
85 2
TOTAL 978
4.8 HABITAT SENSITIVITY -- DISCUSSION
As with overall HV, the distribution of cells with high HS scores generally are concentrated in the FPAs. An acquisition strategy that focuses on cells with high Hv usually will include the cells that
have high HS scores. However, some relatively isolated cells receiving high HS scores may be worth
acquiring, because they contain resources, such as a sensitive plant, that can be protected with only
a small amount of habitat. Consequently, those cells with high HS scores should be evaluated
individually to determine whether they should be acquired.
4.9 TOTAL HABITAT VALUWSENSITMTY -- RESULTlS
For each cell, the HV and HS scores were summed to yield a total HV/HS score (Table 8). Only 13
cells (4 percent) scored at least 150 points, 257 cells (26 percent) scored 100 to 145 points, 456 cells
(47 percent) scored 50 to 95 points, and 252 cells (26 percent) scored less than 50 points. Cells that
scored at least 100 points account for approximately 6,183 acres of the approximately 10,000 acres
of natural habitat remaining in the City of Carlsbad.
As with HV and HS considered separately, cells with high totail HV/HS scores are clustered in the
FPAs (Figure 9)- Only six cells within the City boundaries scoring at least 100 points are completely
isolated from other cells scoring at least 100 points. Only seven cells scoring at least 100 points are
connected only at a diagonal to another cell scoring at least 100 points. All other cells scoring at
least 1QO points connect on at least one full side with another cell scoring at least as well.
53
I
I
i
1
1
1
I
1
I
1
1
1
1
I
I
I
1
I
1
-
Carlsbad Habitat Management P
Total Habitat ValuelSensitivity M
TABLE 8
TOTAL HABITAT VALUWSENSITIVITY FREQUENCY DISTRIBUTION
Value Frequency Value Frequency
10 27 90 46
15 30 95 37
20 17 100 38
25 14 105 40
30 34 110 36
35 37 115 36
40 52 120 29
45 41 125 29
50 53 130 24
55 50 135 10
60 46 140 7
65 44 145 8
70 47 150 3
75 43 155 3
80 41 160 3
85 49 165 2
170 2
TOTAL 978
4.10 TOTAL HABITAT VALUWSENSITMTY -- DISCUSSEN
The results for the total HV/HS were similar to the results for HV and HS considered separately.
For this reason, further analyses of the FPAs will focus on the total W/HS scores. These scores will
also be used to determine potential wildlife corridors to link the core preserve areas.
The results suggest that the City of Carlsbad has several areas with high biological value and hence
high potential value as part of a preserve system. Fortunately, as illustrated in Figure 9, these areas
tend to cluster in the FpAs, and thus are at least potentially available for acquisition. Because these
biologically valuable areas comprise more than 6,OOO acres, it is clear that only a subset of the areas
with high HSW will be acquired for the preserves.
From a purely biological perspective, the preserve lands acquisition strategy should include at least
three components:
e
e
Clustered cells scoring at least 100 points should receive top priority in the preserve system.
Cells scoring 50 to 100 points that share a side with higher scoring cells also should be
considered for inclusion in the core preserves, but with a lower priority. These cells may
serve as buffers for the higher quality habitat and as potential corridors.
54
8 As cells are considered for acquisition, potential habitat linkages between core areas sl
be considered.
1
I
I
1
1
I
I
I
I
I
i
I
1
1
I
1
I
I
I
4.11 LIMITATIONS OF APPROACH
The preserve design approach taken here has some limitations. It has been noted that the sen
species data base is not complete because not all areas of the City of Carlsbad have been sun
Also, the number of sensitive species not recognized by the resource agencies has grown considt
in the past few years and, thus, species considered to be sensitive now were not necessarily sur
for in past efforts. Therefore, even for sites with good biological information, suiweys for ser
species may have been inadequate. From the perspective of sensitive species alone, a more con
data base may result in some modifications to the existing preserve planning areas in orc
encompass sensitive species that were not captured in this phase of the work. Work conduc>
Phase 111 of the HMP and beyond will in part be directed to developing a more complete sei
species data base from ongoing and future field work
55
I
1
I
I
-I ,
/
\ SECTION
\
I 8 Preserve Recomwenddt
/
\
BIOLOGICAL RESOURCES AND HABITAT ANALYSIS
in support ofthe ClTY OF CAIUSBAD HABITAT MANAGEMENT PIAN
SECTION 5
PRESERVE RECOMMENDATIONS
1
I
0
1
II
I
t
1
I
1
R
1
1
1
I
I
1
I
5.1 INTRODUCTION
In this section, recommendations intended to assist the City of Carlsbad in assembling a
biological preserve system are provided. This section consists of an analysis of the propose1
preserve areas from which the ultimate preserve system will be built, identification of PO
wildlife corridors that would serve to link the core areas, and an analysis of potential lanc
adjacent to preserve areas in terms of their impacts and ways to minimize those impacts.
The goal of this section is to provide the City of Carlsbad with the information necess
implement a preserve land acquisition strategy. As such, specific minimal preserve boundari
not drawn. Rather, the analysis will allow the City to choose from a menu of alternative prl
options that will result in a viable preserve system in concert with concurrent conservation effi
the region (e.g., the North County MHCP, the Clean Water Program MSCP, and ,the County (
Diego OSHMP). In this way, the City will have the maximum flexibility in implementing the prl
system.
5.1.1 SIZE OF PRESERVE SYSTEM
An important issue for the establishment of preserves is determining the sizes of the individul
preserves and the overall system. The solution to this depends on several factors, including th
needed to support minimum viable populations of the key species included in 1.he preserve
quality of the habitat preserved, connections between core preserve areas, adjacent land use
long-term management of the preserve system. As discussed in Section 4.2, the larger the pres
the better, because species' extinction rates are inversely related to patch size (Diamond 1975; J
and Hubbell 1983; Usher 1987; Soule 1991). Soule et al. (1988) suggest that habitat fragmc
southern California smaller than 250 ha (617 acres) will likely lose some species. All things
equal, smaller preserves require a greater level of protection and more intense, hands-on manag
to remain viable (Noss 1983).
Unfortunately, the fundamental biological information needed to specify the minimum areas rei
by key species is lacking. For this reason, the City of Carlsbad should take a conservative apy
to identifying the areas targeted for acquisition and retain as much flexibility as possi
implementing the HMP. As biological information on key species (e.g., the California gnatc
and orange-throated whiptail) accrues, the preserve system should be fine-tuned to meet the
of these species and maintain functional ecological systems.
5.2 POTENTIAL CORE PRESERVE AREAS
In Section 4.4.1, pre- and post-gnatcatcher focused planning areas (FPAs) were described. The
included undeveloped areas in the City of Carlsbad that have relatively contiguoius natural h
It was clear that the biological preserve system would be developed from some subset of the
because the best remaining habitat in Carlsbad is captured in the -As and much of the habital
would be available for acquisition. However, the amount of natural habitat in the ITAs was fa1
than would be feasible to acquire for the final preserve system. Upon completion alf the habital (HV) and habitat sensitivity (HS) analyses, it was possible to further refine the ITAs. The
of this analysis yielded a set of preserve planning areas. The preserve planning are<
I
56
distinguished from the FPAs in terms of the quality of habitat included. The methodology and results
of this analysis are presented below.
5.2.1 METHODS
In order to refine the FPAS, a simple decision rule about whether to include a specific habitat cell
in the preserve planning area was employed'. Any habitat ciell scoring fewer than 100 points that
was not adjacent to another habitat cell scoring at least 100 points was excluded from the preserve
planning area. Adjacency was defined as the habitat cell sharing at least one side with a cell scoring
at least 100 points; Le., connections at corners with cells scoring at least 100 points did not qualify
a cell for inclusion in the preserve planning area. Cells scorin<p fewer than 100 points were included
in the preserve planning area if adjacent on at least one side tgo a high scoring cell because they may
serve as corridors between better habitat or as buffers.
It is important to note that this method was used only to circumscribe potential core preserve areas
and was not intended to identify wildlife corridors. The methotlology to identify corridors is described
below. It also is important to note that the circumscribed areas provide an artificial picture of the
ultimate preserve areas, because the grid overlay was placed in an arbitrary position. The final
preserve areas likely will have boundaries that follow the contoiurs of property boundaries, vegetation,
topography, and other constraints or open space plans included in development projects. The
circumscribed areas described here as potential core preseme areas provide a guide to the best
remaining natural habitat in Carlsbad rather than a specific delineation of where precise boundaries
should fall.
5.2.2 RESULTS
Separate analyses were camed out for the pre- and post-gnatcatcher listing FPAs (see Figures 5 and
6). Figures 10 and 11 show the pre-listing and post-listing preserve planning areas, respectively. Figure 10 shows the vegetation communities occurring in the pre-listing preserve planning areas.
Table 9 provides the acreages by aggregated vegetation type for the pre-listing preserve planning
areas. Figure 11 shows the vegetation communities occurring in the post-listing preserve planning
areas. Table 10 provides the acreages by aggregated vegetation type for the post-gnatcatcher listing
preserve planning areas.
Within the pre- and post-California gnatcatcher listing preserve planning areas, the following
percentages of native vegetation types within the City are included in the total preserve planning
area:
Plre Post
Coastal Sage Scrub 65% 77%
Chaparral 58% 73 %
Native Grassland 23% 27%
Saltwater/Freshwater Marsh 48% 78%
1 The preserve planning areas discussed here were determined prior to minor final revisions of
the vegetation map. A, few cells along the boundaries of the preserve planning areas changed value
in the final run of the habitat value/sensitivity analysis and would not have been included in the
preserve planning areas. Changes to the preserve planning areas as a result of the vegetation
revisions will be considered in Phase I11 of the HMP.
57
LEGEND
Ip mASTM SAT SCRUB
a DlSTllRBEO EOASTA 5A6E SfRUB {DCSS) PISTURBED IIARITIY! SUCCUL Ill S RUB m QIPARRAt 5 UIHERU YMD CRAPbRRAL {SSIE C IF llired Chop)
~~~bl~~~~~~6~~~~~~~~~s)
COASTAL f:YktkN5\iYi:L SACI/CHIPARRAI &#%E:!$!. MIX ip)
B MSTURBEC CHAPPARtt
a YATIYL GRhSS11W @61. Rdiw 61)
DlSIURBED OUUT El UAft2IIME CHAPARRAL BHTURBED COdAL SAWCIIAPARRAt YIX
DfWR3€~ SRASSLIRD a SALIRATER MARSH ( 1Y FRESRIATEE UARSR qFl@ m RlPkRUl WBB (SW. RS. Rp, Riparian) m OM MOBII(D MI d Oak t fdUW) SYCIUORE Iltl&AL bQDkARE (SAk.Sycmort) m €OCAlYPfllf IOPIILARII ~EQC,EIK Idl&Eicr)
1 OElI 1kTW ttW.43pa IlliBpep Mer) a MSIBIIBEB RTLIRD mal vcthnd. W)
m HOW-SAT E 6RASSUltD (RRCL.6L)
kt wrrb)
a lTAq&%H ACTIVE CRKil[lUsE~DlSTIJ Rt$bW \ YAP] tFD 1 /f6.A6RI)
GOLF COURSE UlSTVR ED UA81 AI 6C 01 D YYLLBPED {DEV.DML) VI Preserve Planning Area
-~ ~ ~~~ '4% wc1-2 1.1 m -WildMe Corridor
-
-
-
LEGEND
(rI Preserve Planning Area
"ell wc1-2 I I El I Wildlife Corridor
m
E zv)
z3a zsd
1
I
I
1
I
I
1
CI c z &I
\o d &
m w v) 2 3(
v)
I+
d & 3 223 y'I L &I M E
FWCr
.I
ca=c * v)
26
Ln_ 3
F-l s co 3 8
m N rn Q OF 8 % 03
8 C 08 m 0
t- CI In "3 2 t- 2 d
d NIn 3 N 3 2 4 +
$?w
m E22 d 423 2 pl, gw &is
ae;lg
4 oI QUZ I
1
I
I
I
I
I
I
1
I
*Om *EN
mC "Y 3s EL u 4
rn 0 OS .I "2 8 3 m E& d
0 act: 3 3 M $1 M \o d
e4 c
&I a
0 0 O2 s r3
q g
C 4 2 a
o\ Md 0 M e *- v) m -- $2 8- r3 4 - e
E &Z 13
cu +T -.I 2.3 $3
3s 2 0: - - 2-
$83 82 d Z6Z2 y)"p E *z.
P 10 $a s?, ?, z 2-z rr*Q U
c"m Q a Q-.3 UY v1.
b mu
u om Phnc.' mu
u-3 a5 aa'c0 cu2-z 5 0
a,(
rnZ$ =o
l=m oas 0 * rn 0 Bo 2:Eak
4 E e.5 ~QJ.SUZ e.2~ 0 :*
283 WE: 52 *-E2 u kj '5 gzz ? E g
1
3 0) 2 3.3 $r asr 52 *,om3 mm
TJ .Ycacu> SJ=2 g
'2 0 .-
5 5.z s.~ as ESs; z.~ a .g l= m3m3m am2 g gi +
mQ J=ozo
ag 3: ms SG
W
G *" v) G do- W? 2
m dbN3 2% WFZM m + cu N 33 szg 2 m 23a
CI * N a N PI
mNoG cu h
0 hcu ZNO cu 4 34 6( ", 3
d F * \o
rnN F 2* \e
t E, 53
1,
3 8 d oc) b\D mbmh v, mm *? 4 a a 3
IPI
N
c on
d m oc) r- 0 mu! IA 0 1.- # vr
3 m 2.4 Y,z
Zk v,
z
zn .R 'c)
v)
o\ v, m Q\
z 03'9N N N cu m 3O c m
m
13 PI dmtu3 N 00 F cu m -,
!2 E3 2
N E,
8 2 m
3 cu $3 2 a 600 om r(
v, d
34 se
&
m $8 G"83, m 3?% ('? PI m c$? 2 Nr,
e
H b 0- H N
a c a d 2 L a 3 .? 2
w 55 a 0 L! .z 0
Yk
B ss T1 2g e e E- zs G % % iqg5 22 1 zg g xi % 0 p&d
z1L 2 +2 32 b 3 X$ ->lo2 TI ms 2 smwz 1
.I ;;; Qm 3 *I 3 $3 3 i2 e; gs 2 $-&p 3 Q) 23 L, g Aim E ';ij u c E; 2.2 y bbb%
on I .- m K 88 000 2 P Grt; & Om 3 82 a" bbb$
a Q)
u c
'2
.-
L2 OQ Y 0
I
1
1
1
I
1
1
I
8
1
I
I
1
1
1
1
I
m id Eg
0, 2% gi3 wtrq
FEU
+ BET g cq
2 ;SF
oq -eg Ed&
giy 3 ccla
ci5
b4
0%
02
0
u c
r *- m 2 2& co 3 In 3
.r(
3 ZSa sZ$ In
I? og b N -3 8 m g 8 2 00
d
d c.l
e
\o m 0 0 0 00
&
F F v) d\o d
VI 2 -3 2 F
vl a
42 2 2
3 8 * 2 g$ $1 f3
&l
2 d d d cob N 0 OB
e $1
M E: .I c vl
0 om Jrn v,
ell
3 N 0 om Q\ 00 2 *% 2 v) v, a
0 0 O13
3 0, 0 i 2 e
-3 v) m v? %
3 *- % In In
U
d
4 q Q\* 3 F&
..I c, m a- d - 5.8 52
a 82 2..
3 * 32 2 2 % az m- 38 39 $A2
5; m $$$ ce 5; =%* mu &- E z .8 I w;$- s2z - 22 a sass c 2: &rnS 3QC -$ 322
0-3 gz 0 a*zU 2$% *3g .?Smm> &&Z 3 c3i 3 QC * a 3. ged)& - E p, 2 0.Y03 e.cu d) $4 ; g):; 3.5 gs €5 a 3.23 -2 a3m3m SmgJ * g? 5 m.22 .YQ soso % Sar: aT: U~O~Q a~m E zi
a L mu
u
0)
a
583 82 I zm2 $:wl :v% aa: 0 E -2, * 1 3 0 .I
*
>
G 2” m r- 00 8GY3P 3 a N 22
d =sg 8 zs5r
ez oc) d d dm ZNC9C‘ 2
G -3
4 In 5, 5,
\o * PO rcl N c>
5r 5r
N r4 rclN 4 2 TP
8 MC‘U’,+ m Q& *\o In oc) #
4 & 5,
i2 ?D
v, 2 a - 8 -w .-.I 0 ma * i! 2 - Ye& M
G .I c) v) 2 0 %iS~L& 7-4
5
CJ G de4 0s SVl F wg Ed
bs
2 4 ‘J &aE rrr: 40
Is: v, 8 r4 N
N 3%
d
141 2 5,
4 %a 2 Tt. m CJ CMC3In bb d d Ec
N 3- fi 3 ‘2 N 22 2 T.. 4
dQ c .- cn 2
7-4 SEc
6 2 m a 0 .k cd 8
$ 2 c3
k2 s 2 T1 oJ
5Jm c 82 - 3 $: .o,= 4 ;;I3 *= h sz ; c 3 2.2 0
C%Lz -- & owl m”x ts Q< Q
us L rn
mw $s dd T? E: “;s m cu s E
J
u w =E *- 0
-2
2: oz % 4.4 s a$
Zh $5 g t s 23 s m $ $ z mc 3
5; g 24m u 8 2 .2b ti
0 .(I k 5 e4 3 >
3 3 d
G!
Q!!
74
4 b \o
4 d “!. 7-4
d v, M
ri
3
t‘,
d Q
\o d :-
m o\ m
MQO sad z- $!
c\1
3
Z<U? i? EN
E&&$
“*On h2LZ a!$$:
&Or-
bbbz 0002 bbbm
PN? Pmt
Riparian Scrub 53% 7'6%
1
I
1
!
I
I
I
1
I
1
I
I
I
1
1
I
D
1
OaldSycamore Alluvial Woodland 82% 900%
Open Water 97% 96%
With the exception of native grassland, and salt and freshwater marsh under the prie-listing scei
the majority of native habitat within the City is included in the preserve planning areas. Sal
freshwater marsh, however, already have statutory protection.
The preserve planning area analysis allows for the designation of those areas in Carlsbad
constitute the best remaining habitat within the City. The fact that the City retains; more than
acres of good habitat under the pre-gnatcatcher listing alternative and nearly 9,4013 acres undr
post-gnatcatcher listing alternative indicates that the City has an excellent opportunity to asst
a biological preserve system. Each preserve planning area is considered in detail below.
Sensitive Species
Figure 4 shows the distribution of sensitive species in the City of Carlsbad and Section 2 prov
detailed discussion of each species. Information concerning sensitive species was gathered
existing EIRs, other environmental documents, and discussions with local experts. Tables 11 r
provide a matrix of records for sensitive species by preserve planning area for both the pre- anc
listing scenarios, respectively.
Under the pre-listing scenario, preserve planning areas 2,4,5, and 7 contain a good diversity c
sensitive wildlife and plant species. Under the post-listing scenario, the results are similar, wi
exception that preserve planning area 3 captures much greater diversity, because its area is h
expanded, from 859 acres to 1,708 acres.
Tables 11 and 12 list all the sensitive species recorded from the preserve planning areas bai
information available for the present study. There certainly are more instances of sensitive 2
occurring in these areas than presented here. For example, the Belding's Savannah sparrou
is much more widespread in the salt marsh habitat around the lagoons than reflected in thesi
1
Not all of the sensitive wildlife and plant species occurring in Carlsbad are captured in the PI
planning areas. These omissions may reflect gaps in the ultimate protection of these areas.
other hand, existing protected lands or designated open space may provide protection for SI
these resources. Resolution of such questions requires performance of a "gap analysis", wh
be performed in Phase III of the HMP work plan.
62
TABLE 11
PRE-CALIFORNIA GNATCATCHER LISTING
PRESERVE PLANNING AREA SENSITIVE SPECIES RECORDS
Preserve Planning Areaa
Species 1 2 3 4 5 6 7
WILDLIFE
BeMing’s Savannah Sparrow
California Least Tern
Least Bell’s Vireo
Light-footed Clapper Rail
California Gnatcatcher l& .2 6 13 35
Orange- throa ted Whip tail 3 2
San Diego Homed Lizard 2
PLANTS
Ashy-spike Moss x X X X
California Adolphia X X X
Del Mar Manzanita X X
Engelmann Oak X X
Orcutt’s Brodiaea
San Diego Golden-star X
San Diego Thorn-mint
Spiny Rush X X X
Summer-holly X X X
Wart-stemmed Ceanothus X X
Western Dichondra X X
a Based on existing available data. New surveys were not performed in potential PPAs
b Indicates number of records
Indicates presence C
63
TABLE 12
1
1
I
I Species 1 2 3 4 5 6 7
1
I
I
t PLANTS
1
1
1
I Western Dichondra X X
1
I
D
1
I
1
1
POST-CALIFORNIA GNATCATCHER LISTING
PRESERVE PLANNING AREA SENSITIVE SPECIES RECOROS
Preserve Planning Areal
WILDLIFE
Belding’s Savannah Sparrow 1
California Gnatcatcher 16 6 7 13 4(
California Least Tern 1
Least Bell’s Vireo 1
Light-footed Clapper Rail 1
Orange-throated Whiptail 3 2
San Diego Homed Lizard 2
Ashy-spike Moss X X X X X
California Adolphia X X X X x
Del Mar Manzanita X X x
Engelmann Oak X X
Orcutt’s Brodiaea x
San Diego Golden-star X
San Diego Thorn-mint X X
Spiny Rush X X X X
Summer-holly X X X
Wart-stemmed Ceanothus X X X X
Sensitive species known to occur outside of the pre-listing preserve planning areas include:
Belding’s Savannah Sparrow
Light-footed Clapper Rail
California Least Tern
Least Bell’s Vireo
Chocolate Lily
Cliff Spurge
Del Mar Mesa Sand Aster
San Diego Marsh Elder
Thread-leaved Brodiaea
The post-listing preserve planning areas capture more sensitive species, because they are 1
However, sensitive species known to occur outside of the post-listing preserve planning areas inc
64
Chocolate Lily
Cliff Spurge
Del Mar Mesa Sand Aster
San Diego Marsh Elder
Thread-leaved Brodiaea
Fortunately, most of the species not captured by the preserve: planning areas are plants that could
be preserved by acquiring small areas of land or implementiing some type of localized protection
program (conservation easements, fencing, etc.).
Based on available information and discussions with local experts, it is estimated that there are
between 113 and 166 California gnatcatcher pairs in the City of Carlsbad (P. Mock, pers. comm.).
The 113 known to the City probably underestimate the total, because some coastal sage scrub habitat
is unsurveyed. Of the known gnatcatchers in the City, the pre-listing preserve planning area includes
approximately 72 pairs and the post-listing preserve planning area includes approximately 82 pairs.
The remaining known pairs tend to be scattered among fragments of coastal sage scrub habitat
throughout the City. Some of these pairs inhabit areas already protected as open space or along
utility easements. Thus, most of the known gnatcatchers subject to the greatest risk are included in
the preserve planning areas. These gnatcatchers also tend to be dustered wherever they occur.
Therefore Carlsbad will have the opportunity to make a significant contribution to the conservation
of gnatcatchers on a regional basis.
Each of the preserve planning areas are discussed in detail below.
Pre-Gnatcatcher Listing Preserve PlanninP Areas
Preserve Planning Area 1 (PPA1)
PPAl consists primarily of the Buena Vista Lagoon in its western portion and Buena Vita Creek
in its eastern portion. This 393-acre area lies at the northwestern border of Carlsbad, and is bounded
by State Highway 78 on the north and urban development on the south. The dominant habitat type
is the open water of the lagoon (108 acres). The eastern portion supports riparian scrub and non-
native annual grassland. The planning area also includes some small patches of disturbed habitat.
As a potential preserve area, PPAl contains highly sensitive wetland habitats. The lagoons and salt
marsh and freshwater marsh habitats are statutorily protected from development under Section 404
of the federal Clean Water Act and Section 1600 of the California Fish and Game Code.
Furthermore, Buena Vista Lagoon is managed as an ecological reserve area by CDFG and is
therefore already under state protection and management.
The open water habitat of the lagoon supports a variety of fishes and provides foraging habitat for
numerous waterfowl, diving birds, and shorebirds. Sensitive wildlife species likely to occur in the
lagoon or the associated salt marsh include the Belding’s Savannah sparrow, light-footed clapper rail,
California least tern, and salt-marsh skipper. Freshwater marsh provides habitat for two sensitive
plant species: spiny rush and San Diego marsh elder.
Carlsbad will need to manage the watershed and tidal influences that affect the viability of the lagoon,
as well as Batiquitos and Agua Hedionda lagoons. While the lagoons and marsh habitat currently
have statutory protection, and thus do not require acquisition, the HMP should include provisions
for preserving or enhancing the quality of these valuable resources. A concern recently voiced is the
enforcement of runoff control measures to reduce sedimentation into the lagoons, and in particular
65
Batiquitos. Another concern is to manage the watersheds of the lagoons to ensure a: balance bet
freshwater and tidal influences on the fragile lagoon ecosystem.
Preserve Planning Area 2 (PPA2)
PPA2 contains 2,113 acres generally located east of Tamarack Avenue, northeast of El Camino
and north of Palomar Airport Road. The dominant vegetation in this area is coasi;al sage scru
chaparral (1,114 acres), with relatively large patches of disturbed habitat interspersed with the
scrub and chaparral. This area supports one of the two remaining areas in Carlsbad with
contiguous stands of coastal sage scrub. Other notable features in PPA2 include L,ake Calaver
Squires Dam, riparian scrub, and well developed oak woodlands in the southern portion of the
The important habitat in PPA2 occurs in three large blocks: around Lake Calavera, the blc
coastal sage scrub east of Rancho Carlsbad Golf Course, and the block of coastal sage scru
chaparral around Agua Hedionda Creek in the southeast portion of the planning asea. The no1
and southern portions contain the greatest diversity and density of sensitive species. These
should be the focus of future acquisitions. Ideally, these sub-areas would be acquired as large h
blocks connected by wildlife corridors. The woodland along Agua Hedionda Creek would pi
a potential connection between the more southern habitat blocks.
PPA2 supports substantial coastal sage scrub (550 acres) and the second greateslt concentral
gnatcatchers in the City, as well as several other sensitive species (Table 12). Portions of PPr
serve as a key part of the preserve system .
Preserve Planning Area 3 (PPA3)
PPA3 is an 859-acre area primarily comprised of Agua Hedionda Lagoon (264 acres) in th
portion. The area lies south of Tamarack Avenue, north of Palomar Airport Road, and is bi
by Hidden Valley Road. The eastern portion of PPA3 supports riparian scrub and relativelj
areas of coastal sage scrub in the eastern portion. The greatest value of PPA3 is the lagoc
riparian scrub, because these areas already have statutory protection. The remaining habitat ic
is marginal: the patches of coastal sage scrub and chaparral would become fragmented with e\
development to the north and northeast (e.g., Evans Point) and thus will not connect with othe
or chaparral in the City available for acquisition under the pre-listing scenario.
Preserve Planning Area 4 (PPA4)
PPA4 is a 679-acre area bordered on the north by Palomar Airport Road, on the east by El C
Real, and on the north and south by development. This area contains patches of maritime su(
scrub in the western portion, chaparral in the central and eastern portion, and some smaller i
riparian scrub and oak woodland. Much of PPA4 supports non-native grassland and disturbed
(310 acres). The coastal sage scrub in PPA4 borders relativeiy large stands of sage scrub to th
and south, but these areas are rapidly urbanizing. It is unlikely that the coastal sa;ge scrub rex
in this area will retain high biological value over the years unless adjacent development I
include preservation of substantial areas of coastal sage scrub. The chaparral in the cent
eastern portion of PPA4 is intact and connects to some large patches of chaparral to the
PPA5. The chaparral-oak woodland mosaic in the eastern part of the area is the best ha 1 PPA4.
I
1
I
I
1
I
1
1
I
1
1
I
1
1
1
I
1
1
The primary value of PPA4 is that it contains a variety of sensitive plants associ<ated with II
succulent scrub. Fortunately these patches of habitat can be preserved without requiring acq
of large areas or connections to other habitat, since the primary purpose will be to preserve s
vegetation.
66
Preserve Planning Auea 5 (PPAS)
PPA5 contains 1,341 acres. The area is bounded on the north by Palomar Airport Road, on the
south by Alga Road, an the west by El Camino Real, and or1 the west by the City of San Marcos.
PPA5 supports a patchwork of coastal sage scrub, chaparral, oak woodland, and riparian scrub. The
dominant vegetation, however, is non-native grassland (446 acres). The coastal sage scrub and
chaparral habitats in PPA5 are much more fragmented than the habitats in PPA2 or PPA7.
However, the coastal sage scrub on the eastern boundary of PPA5 connects with substantial coastal
sage scrub in the City of San Marcos.
Despite the apparent fragmentation of habitat in PPA5, thiis planning area supports at least 13
gnatcatcher pairs and a variety of sensitive plants (Table 12). PPA5 also would serve an important
function as a link between the coastal sage scrub and chaparral habitats in PPA2 and PPA7.
Potential corridors exist along the western edge of the area, just to the east of the western edge, and
in the eastern part of PPA5. The habitat along the western edge, which parallels El Camino Real,
consists primarily of chaparral and does not connect to other large chaparral patches. The more
interior comdor is comprised of discrete but proximate patches of coastal sage scrub and riparian
scrub. This potential corridor may function for coastal sage scrub species such as the gnatcatcher.
The eastern comdor would require the assemblage of small fragmented patches of coastal sage scrub
and riparian habitat to serve as a conduit for coastal sage scrub species. The most promising habitat
link lies to the east and would connect with coastal sage scrub habitat in San Marcos (see discussion
of wildlife comdors below).
Preserve Planning Amis 6 (PPA6)
PPA6 consists of the Batiquitos Lagoon area and comprises 671 acres. This area is bordered on the
south by La Costa Avenue and the City of Encinitas, on the east by El Camino Real, and on the
north by residential development and disturbed habitat. PPA6 is dominated by the open water
habitat of the lagoon, with salt and freshwater marsh along the edges (529 total acres). As described
above for the Buena 'Vista Lagoon, biologically this habitat is extremely valuable and sensitive.
Sensitive species likely to occur also are as described above. The CDFG manages the Batiquitos
Lagoon as an ecological preserve, and thus it is already under state protection.
Preserve Planning Area 7 (PPA7)
PPA7 consists of a 1,322-acre area located in the southeastern portion of the City. The property
primarily is owned by the Fieldstone Company. This area is bisected by Rancho Santa Fe Road,
bordered on the north by Alga Road, and on the southeast by ,the City of Encinitas. PPA7 supports
the largest contiguous stand of coastal sage scrub in the City of Carlsbad and currently provides
habitat for at least 35 gnatcatcher pairs. The remaining habitat in the PPA7 mostly is comprised of
chaparral (205 acres) with smaller patches of non-native grassland and disturbed habitat in the central
portion. There also are small areas of riparian scrub and a small area of open water.
In addition to gnatcatchers, PPA7 supports a variety of sensitive plants. PPA7 will be a significant
part of the preserve system because of its coastal sage scrub habitat. In coordination with the
USFWS and the City of Carlsbad, the Fieldstone Company hi3S a pre-listing Habitat Conservation
Plan (HCP) proposal for preservation of nearly 500 acres of coastal sage scrub and gnatcatcher
habitat as mitigation for their residential development project and the widening of Rancho Santa Fe
Road. This preserved habitat will be a keystone of the City's preserve system and will provide a link
to other gnatcatcher populations and coastal sage scrub in the City of Carlsbad, as well as with coastal
sage scrub habitat outside of the City. This regional linkage will be essential for the viability of the
67
Carlsbad gnatcatcher population and will contribute to the viability of the regional gnatc
population.
Post-Gnatcatcher Listing Preserve PlanninP Areas
The post-listing preserve planning areas are larger than the pre-listing areas because they i
undeveloped areas that have an approved tentative map. However, there is a great deg
concordance between the two sets of planning areas. In this section, significant differences
preserve planning areas are noted.
Preserve Planning Area 1 (PPA1)
Same as pre-listing PPAl.
Preserve Planning Area 2 (PPA2)
PPA2 generally is the same as the pre-listing PPA2. The post-listing PPA2 contains 2,44(
generally located east of Tamarack Avenue, northeast of El Camino Real, and north of P
Airport Road. The dominant vegetation in this area is coastal sage scrub and chaparral (1,261
with relatively large patches of disturbed habitat interspersed with the sage scrub and chaparrs
post-listing scenario differs from the pre-listing scenario primarily in the addition of a large ;
coastal sage scrub in the northern portion. While addition of this area increases the amc
coastal sage scrub in PPA2, there are no records of gnatcatchers in the added habitat. Th
does, however, support a substantial population of California adolphia.
Preserve Planning Area 3 (PPA3)
The post-listing PPA3 extends the planning area well to the north and south of the pre
planning area. PPA3 contains 1,708 acres including the Agua Hedionda Lagoon, marsh ha
mosaic of coastal sage scrub, chaparral, non-native grassland, and disturbed habitat in the n<
portion. The value of the post-listing PPA3 is significantly improved over the pre-listing plannii
via the addition of substantial sage scrub and chaparral. The number of sensitive wildlife an
species captured greatly increases by the expansion of PPA3 (Table 12). Also, the expand€
creates more opportunities for connecting the adjacent preserve planning areas.
Preserve Planning Area 4 (PPA4)
The post-listing PPA4, at 854 acres, is somewhat larger than the pre-listing PPA4, with the a
of some coastal sage scrub and non-native grassland in the northwest comer and some chapar
eucalyptus stands in the southern part. However, much of the habitat in PPA4 is non
grassland and disturbed habitat. With the additional habitat in the north, PPA4 could serve a
between PPA3 and PPA6. As described above, the primary value of PPA4 is the large nun
sensitive plants that occur in the area.
Preserve Planning Area 5 (PPAS)
The post-listing PPA5 is the same as the pre-listing PPA5.
Preserve Planning Area 6 (PPAB)
The post-listing PPA6 is the same as the pre-listing PPA6.
1
I
I
I u
I
1
I
1
1
1
I
I
1
1
1
1
I
I 68
Preserve Planning Am 7 (PPA7)
The post-listing PPA7 encompasses the pre-listing PPA7 and adds habitat in the extreme southeast
comer of the City for a total of 1,983 acres. As described above, PPA7 includes the largest single
area of continuous coastal sage scrub in the Carlsbad. The areas to the south add some areas of
chaparral, coastal sage scrub, and riparian scrub, but the additional area mostly supports non-native
grassland. However, the number of known gnatcatchers in PPA7 is 40 and the number of sensitive
plants increases as well (Table 12). The addition of these areas also provides the potential for linking
PPA6 (Batiquitos Lagoon) and PPA7 via riparian scrub habitat.
53 POTENTIA L WILDLIFE CORRIDORS
As discussed in Section 4.2.3, the degree of isolation of individual presemes is an important design
consideration, because one of the functions of a preserve system is to promote regional biological
diversity. For maintenance of biodiversity, it is assumed that at least modest levels of migration
between preserves via habitat linkages or wildlife corridors must occur to prevent local extinctions
within the individual preserves. Some of the key factors for wildlife corridors to function effectively
are: (1) isolated preserves must be as close together as possible to facilitate exchange of individuals
between subpopulations (Diamond 1975; Wilson and Willis 1975); (2) corridors must be wide enough
to overcome edge effects; (3) corridors must possess appropriate habitat and cover for the key species
expected to travel through them; and (4) corridors must have as few turns or other barriers to
movement as feasible (Soule and Gilpin 1991).
53.1 METHODS
Potential wildlife corridors linking the preserve planning areas in Carlsbad were identified by
examining the vegetation map with the pre- and post-listing planning area overlays (see Figures 10
and 11). Those areas identified as possible corridors provide either the shortest physical link between
two preserve planning areas or areas with continuous or nearly continuous habitat that wildlife could
use for movement and cover. In several cases, the corridors crciss major roadways such as El Camino
Real or Palomar Airport Road, because there is no other way of connecting preserve areas. In these
cases, the habitat of the planning areas generally abuts the road. These kinds of corridors will be of
limited value, however, because they would preclude use by certain species.
Not all of the corridors identified will be functional or desirable. In some cases, a corridor may
effectively link two areas, but be non-functional because the two preserves support different species.
Such a corridor could even be detrimental in the long term because animals using it may be at greater
risk to predation resulting from edge effects, relative lack of cover or refuge, and unfamiliarity with
the area. The corridor, in essence, acts as a "sink" for individuals and serves to reduce numbers in
the feeder populations.
The dashed lines signifymg wildlife corridors in Figures 10 arid 11 represent strips 375 feet wide.
Ideally, corridors should be at least 1,OOO feet wide to provide adequate cover and space for the
wildlife. However, the minimum width will depend on the type of habitat, the length of the corridor,
and the amount of cover provided. (See discussion of buffers and distance setbacks provided in
Section 4.2.4.)
It is important to keep in mind that the corridors discussed bebw refer only to potential connections
between preserve planning areas. Because the preserve planning areas represent the best remaining
contiguous natural habitat in the City, the proposed corridors almost always will consist of more
degraded or fragmented habitat. Also, as the preserve planning areas are further refined, corridors
within the preserve planning areas will become important (Le., local or internal corridors). The same
69
'
principles discussed below for the corridors will apply to the local corridors. Fortunately, bc
these corridors would be developed in habitat considered of high biological value, it should be
to design connections that contain appropriate habitat and adequate space.
53.2 RESULTS
Pre-Gnatcatcher Listine Wildlife Corridors
Figure 10 illustrates the potential wildlife corridors under the pre-listing scenario. For brevi
wildlife corridors are coded by the preserve planning areas they connect. For example, the u
corridor between PPAl and PPA2 is coded as WC1-2. Where there are multiple corridors conn
two preserves, a capital letter is added to the code to distinguish the different connections.
WC1-2 is approximately 2,000 feet in length and crosses patches of coastal sage scrub. The va
this corridor is questionable because it connects the coastal sage scrub in PPA2 with non-
grassland in PPA1, and thus would not serve a useful function for coastal sage scrub species.
is an example of a wildlife corridor that could function as a sink for some species. Larger mar
such as coyotes, foxes, skunks or raccoons probably would use this corridor.
WC2-SA bridges a gap of approximately 2,600 feet between chaparral north of Palomar Airpor
in PPA2 and chaparral to the south in PPM. The corridor crosses Palomar Airport Ro;
disturbed habitat. The major impediment posed along this corridor is the roadway. Palomar r!
Road receives heavy traffic flow during the day, which would preclude diurnal movements of u
Species capable of moving at night, such as coyotes, foxes, raccoons, skunks, and perhaps bc
may be able to cross the roadway without great risk. Rabbits and rodents also may effectivc
this corridor.
WC2-5B connects PPA2 and PPA5 via strips of coastal sage scrub and disturbed habitat approxi
3,700 feet long and about 700 feet wide. It ties in oak woodland in PPA2 with a patch of I
sage scrub in PPA5. This corridor could function for larger species as well as small coastal sagc
species. The major obstacle in this corridor is Palomar Airport Road, which may inhibit or pr
movement by some species as described for WC2-5A.
WC4-5 connects the east part of PPA4 with the west part of PPM. This corridor would CI
patches of chaparral in the two preserve planning areas and may link areas of oak woodland
two preserve areas. The major drawback to this linkage is that it crosses El Camino Real,
poses an obstacle to smaller and diurnal species. Larger nocturnal species likely use this CI
without much difficulty. As discussed above, however, the main biological value of PPA4 comc
sensitive plants species. The wildlife in PPA4 is threatened by urbanization to the north. The
a wildlife corridor linking PPA4 and PPA5 probably is of low priority.
WC4-6 connects the southern portion of PPA4 with the northern portion of PPA6 at Bar
Lagoon. The corridor crosses Alga Road and extends approximately 5,000 feet through disturt:
eucalyptus woodland habitat. Because of the lack of cover and the obstacle posed by Alga Ro
of the corridor would be limited to crepuscular and nocturnal movements by species such as I
foxes, raccoons, coyotes, and perhaps bobcats. The eucalyptus woodland provides habitat for
1
i
1
1
R
I
1
I
I
IC
I
I
1
I
1
1
1
il
1 and other birds.
WC5-7A is located east of the City boundary and connects PPM with PPA7. It t
approximately 6,000 feet, of which 4,500 feet is coastal sage scrub, 1,100 feet is riparian scri
400 feet is developed. This may be a critical link between the coastal sage scrub habitat and
sage scrub species in the southeast portion of Carlsbad and that in the City of San Marcos.
70
WC5-7B is a 3,300-foot corridor approximately 300-400 feet wide that connects PPM and PPA7. It
follows an existing powerline easement. The corridor primarily supports non-native grassland and
probably serves as a corridor for larger species such as coyotes, foxes, and skunks. It would not be
particularly useful for coastal sage scrub species because there is relatively little scrub habitat in
PPM. Small species that use non-native grasslands, such 25 rodents and rabbits could use this
corridor as well.
WC5-6,7 comprises La Costa Golf Course. It connects PPA5 and PPA7 and links with PPA6 via a
strip of marsh and disturbed habitat. While golf courses do not :serve as corridors for many sage scrub
and chaparral species, larger mammalian species such as coyotes and rabbits will use such areas for
movements. The connection to PPA6 would provide a corridor for species using Batiquitos Lagoon.
Post-Gnatcatcher Listing Wildlife Corridors
WC1-2 is the same as the pre-listing WC1-2.
WC2-3A is a 3,700-foot corridor that connects PPA2 and PPKI. This corridor includes coastal sage
scrub, non-native annual grassland, and disturbed habitat. It links coastal sage scrub habitat in PPA2
with riparian scrub, eucalyptus woodland, and disturbed habitat in PPA3. There are areas of
chaparral and coastal sage scrub in the northern part of PPA3 that potentially could link with PPAZ
habitat via this corridor, The drawback to this corridor is that it crosses El Camino Real below the
intersection of El Camino and Tamarack Avenue, thus precluding or inhibiting the movement of
diurnal and smaller species that would have difficulty safely crossing a four-lane thoroughfare.
WC2-3B is a 4,500-foot corridor that connects PPA2 and PPA3 just to the east of WC2-3A via
riparian scrub. This corridor, although lengthy, directly connects coastal sage scrub in PPA2 with
riparian scrub on PPA3. Again, however, the corridor must cross El Camino Real, thus providing an
obstacle to the movement of many animals. The other main dlisadvantage of this corridor is that it
is rather narrow -- generally less than 200 feet wide and is adjacent to disturbed habitat.
WC2-3C is a 1,500-foot corridor that connects riparian scrub in PPA2 with eucalyptus woodland in
PPA3. A patch of chaparral lies southwest of the eucalyptus. This may be an effective corridor for
some avian species that can use the riparian scrub and oak woodland to the east in PPA2 and also
utilize the eucalyptus woodland and riparian habitats in PIPM. As with the other corridors
connecting PPA2 and PPA3, El Camino Real provides an obstacle to movement between the two
areas, although it would not be an obstacle to many avian species.
WC2-§A is the same as the pre-listing WC2-5A.
WC2-53 is the same as the pre-listing WC2-5B.
WC3-4 is a 5W-fOOt corridor between PPA3 and PPA4. This corridor probably would not serve an
important function because it is interrupted by Palomar Airport Road. Also, the western end of
PPA4 has questionable value as a wildlife preserve because is consists of a patchwork of coastal sage
scrub, non-native grassland, and disturbed habitat.
WC4-5 is the same as the pre-listing WC4-5.
WC4-6 is the same as the pre-listing WC4-6.
WC5-7A is the same as the pre-listing WC5-7A.
71
WC5-7B is the same as the pre-listing WC5-7B.
WCS-6,7 is the same as the pre-listing WC5-6,7.
WC6-7 is a 3,oot)-foot corridor that connects the eastern end oE PPA6 and the western end of 1
The corridor supports riparian scrub that is 500-700 feet wide. This corridor would serve to cc
marsh areas in PPA6 with riparian scrub in PPA7. An obstacle for this corridor is the La
Avenue-El Camino Real intersection area. This corridor likely would be effective for avian si
that use the marshkiparian habitats, but limited for small mammals.
WC7-7A is an 1,100-foot corridor that connects two parts of PPA7. The corridor supports non-
grassland and connects non-native grassland areas in the two parts of PPA7. There also are
patches of coastal sage scrub, riparian scrub, and chaparral near the corridor connectior
potentially could benefit from the linkage.
W7-7B is a 1,500-foot corridor that connects two parts of PPA7. The corridor contains disi
habitat and non-na tive grassland. 1 5.4 CONCEPTUAL PRESERVE SYSTEM
I
1
1
1
I
I
t
I
I
1
1
i
I
I
I
i
1
I
Under the City of Carlsbad Draft Comprehensive Open Space and Conservation Re:
Management Plan, dated January 3, 1992, three existing preserves are present within the
Batiquitos Lagoon, Buena Vista Lagoon, and the University of California Reserve. The
conservation proposal between the City, Fieldstone, and the USEWS concerning gnatcatche
coastal sage scrub would establish a fourth preserve of nearly 500 acres in the vicinity of R
Santa Fe Road. Assuming that the lagoons and associated marshhetland habitat, riparian scri
woodland habitat, and the Fieldstone site have protected status, approximately 2,500 acres of 1
in the City is protected. This does not include areas already under City protection provic
General Plan and zoning controls, such as hillsides, steep slopes, canyons, or areas identified
of the City trails system. Those protected lands still must be added to the information t
identify valuable, yet unprotected, lands.
The intent of this report is to provide the City of Carlsbad with the requisite biological infor,
to supplement the natural resources already under protection in the City. As such, the infor
provided in the form of the rated habitat cells, preserve planning areas, and potential I
corridors should provide the City with the basic information needed to guide future re
planning.
It is recommended that the City consider acquisition of at least two or three additional habita
to develop a complete preserve system. The best remaining habitat areas in the City are 1
around the western end of Lake Calavera and the riparian scrub running south from the la1
Agua Hedionda Creek area south of Squires Dam, the western portion of PPA.5, and the 1
portion of PPA4. Ideally, the Lake Calavera, Agua Hedionda Creek, and PPA5 areas could be
with wildlife corridors. Local corridors within PPA2 have not been specifically identifiec
corridor between PPA2 and PPM is WC2-5A. PPA5 and PPA7 could be linked with WC5-'
described above, the central portion of PPA4 supports maritime succulent scrub and a vai
sensitive plant species.
corridors.
It is important to note that these recommendations are very general. It is not possible at tk
to specify parcels for acquisition. Several steps are necessary before the City can begin ac
habitat for the preserve system, including:
These areas could be preserved effectively without additional
72
a Identification of habitat areas already under public ownership or part of the Citywide
trails system (Le., the gap analysis)
Identification of habitat areas protected as open space in existing and proposed
development projects
Analysis of how public and protected habitat relates to unprotected core preserve
areas identified in this document
Targeting of specific acquisition areas based upon the above analyses
Focused biological field surveys of targeted areas to validate the habitat analysis
presented here and to provide current information on general and sensitive resource
diversity and abundance
a
a
0
8
5.5 COMPATIBLE LAND USE ANALYSIS
One of the difficult challenges for designing and implementing a preserve system in the City of
Carlsbad will be to specify appropriate buffers and setbacks between development and preserve areas,
as well as to define acceptable human uses of preserve areas. A discussion of buffers and setbacks
is presented in Section 4-, along with some recommendations relating to different habitat types. These
recommendations are based on guidelines from the San Diego County RPO and a separate set of
guidelines from PSBS.
There are very little data on the impacts of development on preserve areas. One point of general
agreement, however, is that buffers and setbacks should not be considered as part of the preserve
area. These areas will certainly be degraded by human related activity. Researchers presently are
conducting studies on the "naturalhrban interface" and some guidelines should be forthcoming in the
next few years (e.g., Scott 1992; Savaujot 1992).
In the absence of quantitative data on impacts by development, there are a few general guidelines
that should be followed in delineating preserve boundaries. These guidelines relate to the physical
features of the landscape and planned uses in developed areas.
With regard to physical features, vegetation and topography can play an important role in how well
a natural area is protected by affecting the level of public access to a natural area. In the absence
of an established trail system, dense vegetation (e.g., chaparral, coastal sage scrub, or wetland habitat)
can provide barriers to access by both humans and pets. Likewise, a preserve boundary on a ridgeline
surrounded by steep slopes can restrict access to the preserved area. In natural areas used by the
public, low wooden fencing or planting of shrub species, such as ceanothus or cactus, can serve to
limit trespass into sensitive areas. That is, most people choose the path of least resistance, and few
are likely to make the effort to gain access to rugged or densely vegetated areas. Recreation
activities such as hiking, jogging, walking dogs, and mountain biking should be limited to specified
trails and rigorously enforced. These activities, however, may not be appropriate for some preserved
areas. The general idea is to create a preserve system where easy public access is restricted either
by natural or artificial physical features. Such a benign approach (as opposed to wire fencing, heavy
patrol, etc.) is preferable because of the cost savings and the public's perception of the resource as
available for public enjoyment.
Development adjacent to preserve areas poses varying degree:; of risk to them. Medium and high
density residential development probably poses the greatest riisk, because of the sheer number of
people, noise, lighting, use of nearby open space for recreation, pets, human-commensal species (e.g.,
73
starlings and house sparrows that compete with native species for nesting areas and other resoi
arson and accidental fires, and trash dumping. Preserve areas near residential developmen
require the greatest amount of buffering either through distance, vegetation, topography, or fe
Commercial development poses less of a risk to natural open space because of the limitec
people use these areas, the absence of children, and the absence of pets. The most compatibl
uses include active recreation areas such as parks, athletic fields (although nighttime lighting I:
a problem), golf courses, and active agricultural uses. The greatest risk posed by these uses
be maintenance operations, such as the use of chemicals on maintained turf or crops. Also, c
of runoff from cultivated areas is an important issue.
A final, and very difficult issue, is that of itinerant worker camps scattered throughout the dra
and canyons of Carlsbad. These camps are located in some of the most sensitive habitats in th
(e.g., oak woodlands and riparian areas or any areas with heavy canopy cover and an
understory). The presence of the camps has seriously degraded these habitats because of tra:
garbage, trampling of vegetation, and unsanitary living conditions (e.g., open latrine :
Ultimately, the City will have to address this problem if these sensitive areas are to be pres
Also, many of the areas used by the itinerant workers constitute important wildIife corrido
habitat linkages. The presence of people in these areas certainly disrupts their use by wildlif
5.6 CONCLUSION
The City of Carlsbad has the opportunity to develop a preserve system to conserve a var
general and sensitive biological resources. This analysis provides the biological information nec
for implementing a preserve system within the City that will integrate with regional consel
planning efforts. It is anticipated that the City can effectively develop a preserve system USI
information provided in this document, along with additional information regarding land u
public and private property ownership in the City. This document is a fundamental step
I
i
i
1
I
I
1
1
I
I
I
I
I
I
I
1
I
I
I achieving that goal.
74
I
\
SECTION
Ackn o w ledgem
BIOLOGICAL RF3OURCES AND HABITAT ANALYSIS
in support ofthe CITY OF CARLSBAD HAB~AT MANACEMENT PLAN
I
SECTION 6
I
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
I ACKNOWLEDGEMENTS
Completion of the Biological Resources Inventory and Analysis phase of the Carlsbad Hat
Management Plan was the joint effort of many participants. The HMP Advisory Committee is tc
commended for their faithful attendance and participation at the monthly meetings. Rick Alexa.
of Consultants Collaborative, Inc. provided excellent leadership and guidance in his role as cha
the committee. Don Rideout and Michael Holzmiller of the City of Carlsbad were critical tc
success of the work through their provision of City resources. Bob Parrott, Paula Cunningham,
Sue Carnevale of SANDAG provided GIS services, and Bob wrote the computer program foi
habitat quality analyses. Also important to the success of this project were numerous property ow
and their consultants who provided additional information and corrections to the biological resot
data base. Finally, we thank the many reviewers who provided valuable comments on the (
document .
The following are the biological consultant team members:
H. Lee Jones, Ph.D. -- Project Director, Michael Brandman Associates
Allison Alberts, Ph.D. -- Preserve Design Specialist, Center €or the Reproduction of Endani
Philip R. Behrends, Ph.D. -- Project Manager, Biologist, Dudek & Associates
Nancy Bell-Gallagher -- Graphic Artist, Michael Brandman PLssociates
John W. Brown, Ph.D. -- Biologist, Dudek & Associates
Martie k Clemons -- Graphic Artist, Dudek & Associates
Michael Evans -- Natural Resources Consultant
Sarah k Flick -- Botanist, Michael Brandman Associates
Tonette S. Foster -- Word Processing, Administrative Assistant, Dudek & Associates
Marcia McRae -- Word Processing, Administrative Assistant, Michael Brandman Associates
Gregory Pregill, Ph.D. -- Sensitive Amphibians and Reptiles, San Diego Natural History Mus(
Fran Saveriano -- Regional Business Manager, Michael Brandman Associates
Wayne D. Spencer, Ph.D. -- Biologist, Michael Brandman Associates
Fred T. Sproul -- Sensitive Plant Species, Plant Ecology
Harold (Howie) Wier -- Biologist, Dudek & Associates
Species, Zoological Society of San Diego
75
SECTION
/
Literatwe C
,
\
’ -& BIOLOGICAL RESOURCES AND HABITAT ANALYSIS 3 in support of the ClTY OF CARLSBAD HABITAT MANAGEMENT PLAN
-
i
SECTION 7 I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I LITERATURE CITED
Alberts, A. C., k D. Richman, D. Tran, R. Sauvajot, C. McCalvin and D. T. Bolger. (In prepara
Effects of Habitat Fragmentation on Species Diversity of Native and Exotic Plar
Southern California Coastal Scrub. In J. E. Keely (ed) The Interface Between Ecolog
Land Development in California. Based on a paper presented at the Southern Calif
Academy of Sciences Annual Meeting, Occidental College, May 1-2, 1992.
Atwood, J. L. 1990. Status Review of the California Gnatcatcher (PoliopfiIa califor I Unpublished technical report, Manomet Bird Observatory, Manomet, Massachusetts,
Bauder, E. T. 1986. San Diego vernal pools. Recent and projected losses: their conditior
threats to their existence, 1979-1990. Vols. 1 & 2. Report and Appendices 1-9. Pre
for the California Department of Fish and Game, Endangered Plant Project.
Beauchamp, R. M. 1986. A Flora of San Diego County, California. Sweetwater Press, Nationa
California.
Block, W., M. Morrison, and J. Verner. 1990. Widlife and oak-woodland interdepenc
Fremontia 1872-76.
Blouin, M. S. and E. E Conner. 1985.
Conservation 32: 277-288.
Is there a best shape for nature preserves? Bio,
Boecklen, W. J. 1986. Optimal design for nature reserves: consequences of genetic drift. Bioi
Conservation 38: 323-338.
Boecklen, W. J. and G. W. Bell. 1987. Consequences of faunal collapse and genetic drift f
design of nature reserves. Pages 141-149 in D. A. Saunders, G. W. Arnold, k A. BUI
and A. J. M. Hopkins, (eds). Nature Conservation: The Role of Remnants of
Vegetation. Surrey Beatty, Australia. .
Bond, S. I. 1977. An annotated list of the mammals of San Diego County, California. Trar
Diego Soc. Nat. Hi&. 18: 229-248.
Bowman, R. H. 1973. Soil Survey of Sun Diego Area, California, Part 1. United States Depa
of Agriculture, Soil Conservation Service and Forest Service. 104 pp.
Brown, J. W. 1981. The wandering skipper: at home on the coastal salt marsh. Envirc
Southwest 492:26.
Brown, J. W. and W. W. McGuire. 1983. A new subspecies of Euphyes vestris (Boisduva
Southern California (Lepidoptera: Hesperiidae). Trans. Sun Diego Soc. Nut. Hkt. 20
Sensitive and declining buttefly species in Sun Diego County, Cal Brown, J. W. 1991.
Manuscript. Available from Dudek and Associates, Inc. 20 pp.
Burkey, T. V. 1989. Extinction in nature reserves: the effect of fragmentation and the imp
of migration between reserve fragments. Oikos 55: 75-81.
76
Busnardo, M. 1989. The autecology of Panoquina erram (Lepidoptera: Hesperiidae): preliminary
field and laboratory observations. Tijuana Estuary RestorationEnhancement Project, Spring,
1989.6 pp. + maps.
Carlsbad, City of. 1992. Draft Comprehensive Open Space and Conservation Resource
Management Plan.
Diamond, J. M. 1975. The island dilemma: lessons of modern biogeographic studies for the design
of natural reserves. Biological Conservation 7: 129-146.
Donahue, J. P. 1975. A report on the 24 species of California butterflies being considered for
Submitted to placement on the Federal Lists of Endangered or Threatened Species.
California Department of Food and Agriculture. 58 pp.
Duever, L. C. and R. E Noss. 1990. A computerized method of priority ranking for natural areas. Nau York State Museum Bulletin 471: 22-33.
Emmel, T. C. and J. F. Emmel. 1973. "The Butterflies of Southern California." Natural History
Museum of L,os Angeles County, Science Series 26:l-148.
ERCE. 1991. "Detailed Biological Assessment for the City of Poway." Prepared for City of Poway
Planning Department.
Everett, W. T. 1979. Sensitive, Threatened and Declining Bird Species of San Diego County. San
Diego Audubon Society Sketches 29:2-3.
Faeth, S. H. and T. C. Kane.. 1978. Urban biogeography: city parks as islands for Diptera and
Coleoptera. Oecologia 32: 127-138.
Fahrig, L. and G. Merriam. 1985. Habitat patch connectivity and population survival. Ecology 66:
1762- 1768.
Forman, R. T. T. and M. Godron. 1981. Patches and structural components for a landscape ecology. Bioscience 31: 738-740.
Franklin, I. R. 1980. Evolutionary changes in small populations. Pages 135-149 in M. E. Soule and
B. A Wilcox (eds). Conservation Biology: An Evolutioitaly Perspective. Sinauer, Sunderland,
Massachusetts .
Game, M. 1980. Best shape for nature reserves. Nature 287: 1530-632.
Gelbach, F. R. 1975. Investigation, evaluation, and priority ranking of natural reserves. Biological
Conservation 8: 79-88.
Goldsmith, F. B. 1975. The evaluation of ecological resources in the countryside for conservation
purposes. Biological Conservation 8: 89-96.
Grinnell, J. and A Miller. 1944. The distribution of the birds of California. Pa&& Coast Avifauna
27: 1-608.
77
Hix, A. B. (ed.) 1990. Sensitivity of San Diego’s biological resources: an informational 1
Compiled by City of San Diego Planning Department, Development and Environi
Planning Division (primarily Lisa Wood). 29 pp. + attachments.
I
I
I
I
I
I
I
Holland, R. F. 1986. Preliminary Descriptions of the Terrestd Natural Communities of Cah
Nongame-Heritage Program, California Department of Fish and Game. 150 pp.
Jensen, D. B. 1987. Concepts of preserve design: what we have learned. Pages 595-603 ii
Elias, (ed). Conservation and Management of Rare and Endangered Plants. California
Plant Society, Sacramento, California.
Kelly, P. and J. Rotenberry. (In preparation). Buffer zones for ecological reserves in Califon
J. E. Keely (ed) The Interface Between Ecology and Land Development in California.
presented at the Southern California Academy of Sciences Annual Meeting, Occ
College, May 1-2, 1992.
Lacy, R. C. 1987. Loss of genetic diversity from managed populations: interacting effects c
mutation, immigration, selection, and population subdivision. Conservation Biology 1: 11
Lande, R. and G. F. Barrowclough. 1987. Effective population size, genetic variation, and th
for population management. Pages 87-123 in M. E. Soule (ed). Vmble Populatit
Conservation. Cambridge University Press, Cambridge. I
I Biological Conservation 55: 77-92.
I
I
I
I
Laurence, W. F. and E. Yensen. 1991. Predicting the impacts of edge effects in fragmented hi
Lichtwardt, E. and E. Gold. 1980. Field checklist of Amphibians and Reptiles of San Dieq
Imperial eounties. Special Publ. No. 3, San Diego Herpetological Society.
MacNeill, C. D. 1962. Preliminary report on the Hesperiidae of Baja California. Proceeding
California Academy of Sciences 30: 91-116.
Margules, C. and M. B. Usher. 1981. Criteria used in assessing wildlife conservation poten
review. Biological Conservation 21: 79-109.
Massey, B, W. 1977. A census of the breeding population of Belding’s Savannah Spar
California, 1977. Study VI, Job 1.2, Final Report. California Department of Fish and
McCaskie, G. 1977. A Field Checklist of the Birds of San Diego County. Prepared for San
County Parks and Recreation Department. I
I
I
I
I
I
McGurty, B. M. 1980. Survey and status of endangered and threatened species of reptiles r
occurring in San Diego, California. San Diego Herpetological Society.
Munz, P. 1974. A Flora of Southern California. University of California Press, Berkeley, Cal
1086 pp.
Murphy, D. D. 1988. Challenges to biological diversity in urban areas. Pages 71-76 in E. 0.
(ed). Biodiversity. National Academy Press, Washington, D.C.
78
Murphy, D. D. 19990. A report on the California butterflies as candidates for endangered status by
the United States Fish and Wildlife Service. Draft report for California Department of Fish
and Game Contract No. C-1755. 60 pp.
Noss, R. F. 1983. A regional landscape approach to maintain diversity. Bioscience 33: 700-706.
Noss, R. F. 1987, Corridors in real landscapes: a reply to Simberloff and Cox. Conservation Biology
1: 159-164.
Oberbauer, T.A. 1991a. Southern California Botanists. Unique soils and plants of limited
distribution in the Peninsular Ranges. Paper presented at Symposium of So. California
Botanists. October 26, 1991, CSU Fullerton.
Oberbauer, T. A. 1991b. In P. Abbott and B. Elliot (eds). Geol. Soc. North her., So. Calif. Reg.
Sympos. San Diego, October 21-24, 1991.
Pryde, P. R. 1984. San Diego: An Introduction to the Region. KendalliHunt Publ. Co., Dubuque,
Iowa. 297 pp.
Rea, A. M., and K. L. Weaver. 1990. Ten taxonomy, distribution, and status of coastal California
cactus wrens. Western Birds 21: 81-126.
Reed, P. B. 1988. National List of Plant Species That Occur in Wetlands: California (Region 0).
Biological Report S(26.10). United States Fish and Wildlife Service, Department of the
Interior.
Remsen, J. V. 1978. Bird Species of Special Concern in California. State of California Department
of Fish and Game.
San Diego Association of Governments. 1988. Draft Comprehlensive Species Management Plan for
the least Bell’s vireo. Prepared by RECON. 195 pp. et appendices.
Sauvajot, R. (In preparation). Effects of urban encroachment on wildlife in the Santa Monica
Mountains. In J. E. Keely (ed) The Interface Between Ecology and Land Development in
California. Based on paper presented at the Annual Meeting of the Southern California
Academy of Sciences, Occidental College, May 1-2, 19’92.
Schonewald-Cox, C. M. and J. W. Bayless, 1986. The boundary model: a geographical analysis of
design and conservation of natural reserves. Biological Conservation 38: 305-322.
Scott, T. A. 1990. Conserving California’s rarest white oak: the Engelmann oak. Fremontia 1826-
29.
Scott, T. A. (In preparation). Effect of housing developments on urban bird populations. In J. E.
Keely (ed) The Interface Between Ecology and Land Development in California. Based on
paper presented at the Annual Meeting of the Southern California Academy of Sciences,
Occidental College, May 1-2, 1992.
Shaffer, M. I,. 1981. Minimum population sizes for species conservation. Bioscience 31: 131-134.
79
Smith, J. P., Jr., and K. Berg. 1988. California Native Plant Society’s Inventory of Rar Endangered Vascular Plants of California. Special Publication No. 1 (4th Edition), Cali
Native Plant Society, Sacramento, California. 168 pp,
I
I
I
I
I
1
I
Soule, M. E. 1991. Land use planning and wildlife maintenance: guidelines for conserving N
in an urban landscape. Journal of the American Planning Association 57: 313-323.
Soule, M. E., D. T. Bolger, A. C. Alberts, J. Wright, M. Sorice, and S. Hill. 1988. Reconsti
dynamics of rapid extinctions of chaparral-requiring birds in urban habitat is
Conservation Biology 2: 75-92.
Soule, M. E. and M. E. Gilpin. 1991. The theory of wildlife corridor capability. Pages 3-8 in
Saunders and R. J. Hobbs (eds). The Role of Corridors in Nature Conservation. Surrey E
Sydney, Australia.
Souie, M. E. and D. SimberIoff. 1986. What do genetics and ecology tell us about the de:
nature reserves? Biological Conservation 35: 19-40,
Stebbins, R. C. 1985. A Field Guide to Western ReptiZes and Amphibians. Houghton Miffli
Boston, Mass. I
I Conservation 3: 169-172.
I Oregon.
I 276 pp.
Tans, W. 1974. Priority ranking of biotic natural areas. Michigan Botanist 13: 31-39.
Tubbs, C. R. and J. W. Blackwood. 1971. Ecological evaluation for planning purposes. Bic
United States Fish and Wildlife Service. 1988. Least Bell’s Vireo Draft Recovery Plan. Po
Unitt, P. A. 1984. Birds of San Diego County. Memoir 13, San Diego Society of Natural €
Usher, M. B. 1987. Effects of fragmentation in communities and populations: a revie
applications to wildlife conservation. Pages 103-121 in D. A. Saunders, G. W. Arnolc
Burbridge, and A J. M. Hopkins (eds). Nature Consemation: The Role of Remnants oj
Vegetation. Surrey Beatty, Australia.
I
I
I
I
R
I
I
I
Wells, P. 1990. Review of Arctostaphylos glandulosa complex. Four Seasons. 8: 46-70.
Wiggins, I. L. 1980. A Flora of Baja California. Stanford University Press. 1025 pp.
Wilbur, S. R. 1973. The Red-shouldered hawk in the western United States. Testern Birds 4
Wilbur, S. R. 1974. The status of the Light-footed Clapper Rail. American Birds 28: 8684
Wilbur, S. R., P. D. Jorgensen, B. W. Massey, and V. A. Basham. 1979. The Light-footed t
Rail: an update. American Birds 33: 251.
Willet, G. 1933. Revised list of birds of southwestern California. Pacific Coast Avifauna 21
80
Wilson, E. 0. and E. 0. Willis. 1975. Applied biogeography. Pages 522-534 in M. L. Cody and J. M.
Diamond (eds). Ecology and Evolution of Communities. Belknap Press, Cambridge,
Massachusetts.
Wright, D. F. 1977. A site evaluation scheme for use in the assessment of potential nature reserves.
BwZogical Conservation 11: 293-305.
Wright, D. F. and S. P. Hubbell. 1983. Stochastic extinction and reseme size: a focal species
approach. Ohs 41: 466-476.
Yahner, R. H. 1988. Changes in wildlife communities near edges. Comervation BWZogy 4: 333-339.
Zedler, P. H. 1977. Life history attributes of plants and fire cycles; a case study in chaparral
dominated by Cupressusforbesii, pp. 451-458, in: Mooney, H. and L. Conrad (tech. coor.),
Proceedings of the Symposium on the Environmeniral Consequences of Fire and Fuel
Management on Mediterranean Ecosystems. Palo Alto. California.
Zedler, J. B. 1982. The ecology of southern California coaslal salt marshes: a community profile.
U.S. Fish and Wildlife Senice. FWSlOBS-8lR4. 110 lpp. [Second printing with corrections
1984.1
81
,
ERALAND S
' SENSITWEPLANT
\ SPECIES RESIDENT OR BREEDI~
SAN DIEGO Cor
/
/
I
-4@% 3
-% BIOLOGICAL RESOURCES AND HABITAT ANALYSIS
in support oftbe ClTY OF ORLSBAD WBITAT MANAGEMENT PLAN 1 \
I
I
I
I
I
I
I
I
I
I
I
1
e
1
I
I
I
I
FEDERAL AND STATE DESIGNATED SENSITIVE WILDLIFE SPECIES
OCCURRING IN SAN DIEGO COUNTY 1
SPECIES USFWS CDFG
BIRDS
None Ahnophila mfkeps canescens caa
Agelaius tricolor c2 CSe
Ammodramus (Passerculus) sandwichensis beldingi a SI?
Ammodramus (Passerculus) sandwichensis rostrn tus c2 CSC
Southern California Rufous-crowned Sparrow
Tricolored Blackbird
Belding’s Savannah Sparrow
Large-Billed Savannah Sparrow
Amphkpua bellii bellii c2 None
None
Bell’s Sage Sparrow
Campylorhynchus biunneicapillus sandiegensis c2
Charadrius alexandrinus nivosus Cld cse
Coastal Cactus Wren
Western Snowy Plover
Chilodanius niger c2 None
Empidonax traillu &us C1 None
None
Black Tern
Southwestern Willow Flycatcher
Eremophila alpestrk actia c2
California Horned Lark
Falco peregrinus anatum FE? SE
American Peregine Falcon e
Haliaeem leucocephalus FE SE
Bald Eagle
Lank ludovicianus c2 None
Loggerhead Shrike
Laterallus jamaicemis c2 None
Black Rail
Oreortyx pktw c2 None
Moutan Quail
Pejecanus occidentalis califomicus FE SE
Plegadis chihi c2 csC
Polwptila califomica califomica Proposed CSC
California Brown Pelican
White-faced Ibis
California Gnatcatcher Ehdangered
Rallus longirostris IevjPes FE SE
Light-footed Clapper Rail
Stema aniillamm browni FE SE
California Least Tern
Sterna elegans c2 CSC
Elegant Tern
Strix occidentalis occdentalis c2 None
California Spotted Owl
Vieo beliu pusillus FE SE
Least Bell’s Vireo
MAMMALS
None Choeronycteh mexicana IC2
Dr;podomys stephensi :E ST
Mexican Long-tongued Bat
Stephens’ Kangaroo Rat
None Eudenna maculatum (2
Spotted Bat
Eumops peroh ca1ifomicu.s c2 CSC
California Mastiff Bat
Lepus califomicus bennettii (2 None
San Diego Black-tailed Jackrabbit
Macrotus califomicus (2 CSC
California Leaf-nosed Bat
Neotoma lepida intermedia (2 None
San Diego Desert Woodrat
I
Onychomys torridus ramona c2 None 1 Southern Grasshopper Mouse
1 Pennisular Bighorn Sheep
Ovis canadensis cremnobates c2 ST
Perognathus (Chaetodipus) califomicus fernoralis c2 None
Dulzura California Pocket Mouse
a None
8
I
1
II
I
Perognathus (Chaetodipus) fallax fallax
Northwestern San Diego Pocket Mouse
Perognathus (Chaetodipus) fallax pczllidiis a None
Pallid San Diego Pocket Mouse
Perognathus longimembris brevinasus c2 csc
Los Angeles Pocket Mouse
Perognathus 1ongimembi-h internationalis c2 None
Jucumba Little Pocket Mouse
Perognathus longimembrir pacificus c2 ac 1 Pacific Pocket Mouse
1 REPTILES
I California Tiger Salamander m Orange-throated Whiptail s Coastal Western Whiptail
I Southwestern Pond Turtle
Ambystoma califomkme c2 None
Cnemidophorus hyperythrus c2 cse
Cnemidophom tignk multiscutatus c2 None
Clemmys mamarota pallida C1 CSC
Coleonyx swaitaki c2 ST
Barefoot Banded Gecko
c2 None
I
1
I
I
I
Coleonyx variegatus abbotti
San Diego Banded Gecko
c2 None Crotalus ruber ruber Northern Red Diamond Rattlesnake
Diadophus punciatus similis c2 None
San Diego Ringneck Snake
Eumeces skdtonianus inierparieialis c2 None
Coronado Skink
Laanpropelhk zonaia pulchra c2 None
San Diego Mountain Kingsnake
Licharana irivirigata rosamca c2 None
Coastal Rosy Boa
Phrynosorna coronaturn blainvdIei c2 CSC
Phrynosorna mcalli c1 CSC
San Diego Homed Lizard
Flat-tailed Homed Lizard
Salvadora hexalepis v@liea c2 None
Western Patch-nosed Snake
Sauromatus obesus c2 None
Common Chuckwalla
Scetoporus gracwsus vandenburgianus a None
Southern Sagebrush Lizard
Thamnophis harnrnondi c2 None
Two-striped Garter Snake
AMPHIBIANS
Bufo (mkroscaphus califomicus) califoinicus IC2 a&.
AITOYQ Toad
Ensatina eschscholtzi klauberi c-2 CSC
Large-blotched Salamander
Rana aurora drayioni (21 eSC
California Red-legged Frog
Rana mucosa (22 CSC
Mountain Yellow-legged Frog
1
1
I
1
I s
1
1
INVERTEBRATES
INSECTA
Coelus globosus c2 None
Euphydryas editha quho c2 None
Euphyes viestriS harbonsi c2 None
None
Globose Dune Beetle
Quino Checker
Harbison's Dun Skipper
Lycaena hemes c2
Heme Copper
c2 None Mitoura thomei
Thorne's Hairstreak
a None Panoquina errans
Pseudocopaeodes emus e2 None
Qragus ruralis lagunae a None
Salt Marsh Skipper
1 Wandering SEpper
I Laguna Mountains SEpper
1 ANOSTRACA
Branchinecta "sandkgonemb'@ Petitioned for
San Diego Fairy Shrimp Listing as Endangered I
I
1
1
1
I
I
None Streptocephalus woottoni Proposed
Riverside Fairy Shrimp Endangered
e
a C2 -- Category 2 Candidat; b
c SE -- State Endangered
c~ C1 -- Category 1 Candidate!
e FE -- Federally Endangered
f ST -- State Threatened
@
csc -- California Species of special Concern
Species currently undescribed, but under consideration for species status,
Category 2 Candidate for federal listing includes those taxa for which existing
biological information may warrant listing, but for which substantial biological
information to support a proposed listing is lacking.
Category 1 Candidate for federal listing includes those taxa for which there exists
sufficient biological information to support a proposal to list as threatened or
endangered.
*
!
1
STATE AND FEDERALLY RECOGNIZED SENSITIVE PLANT
SPECIES OCCURRING IN SAN DIEGO COUNTY I
II SPECIES USFWS CDFG CNP
Acanthomintha ikicifolia Cl SE List lB,
San Diego Thorn-mint
1
1
I
1
1
I
I
1
1
8
I
1
i
1
I
Ambrosia pumika c2 None List lB,
San Diego Ambrosia
Aphanisma blitoides a None List 3, ?.
Aphanisma
Arctostaphylos otayensis c2 None List lB,
Qtay Manzanita
Astragalus deanei c2 None List lB,
Dean’s Milk Vetch
Astragalus douglasii var. peps frictus c2 None List lB,
Jacumba Milk Vetch
Astragalus magdaleme var. peirsonii c2 SE List lB,
Peirson’s Milk Vetch
Astragalus oocapus c2 None List lB,
Descanso Milk Vetch
Astragalus tener var. tili c2 SE List lB,
Coastal Dunes Milk Vetch
Bacchark vanessae c2 SE List lB,
Encinitas Baccharis
Brodiaea jZifo1i.a c2 SE List lB,
Thread-leaved Brodiaea
Brodkea orcutt% c2 None List lB,
Orcutt’s Brodiaea
Calamagrostis densa c2 None List 4, I
Dense Reed Grass
1 San Miguel Savory
Calamintha (Satureja) chandlen c2 None List 4, 1
Calochottm dunnii c2 Rare List lB, 2-2-2
Dunm’s Mariposa Lily
Caulanthus simulans c2 None List 4, 1-2-3
Payson’s Caulanthus
Caulanthus stenocarpus c2 Rare List lB, 3-2-2
Slender-pod Caulanthus
Ceanothus cyaneus c2 None List lB, 3-2-2
Lakeside Ceanothus (wild-lilac)
Chaenacris parishii c2 None List 4, 1-1-2
Parish’s (Chaenactis
Chorizanthe orcuttiuna c2 SE List 1A
Orcutt’s Spineflower
Chorizanthe pave var. fernandha c1 None List 1A
San Fernando Valley Spineflower
Cora‘ylanthus maritimus ssp. maritimus FE SE List 1B, 2-2-2
Salt Marsh Bird’s-beak
Corethrogyne jilaginifolk var. linijiolia c2 None List lB, 3-2-3
Del Mar Mesa Sand Aster
Cryptantha ganderi c2 None List lB, 3-3-3
Gander’s Cryptan tha
Delphinium hesperium ssp. cuyamacae c2 Rare List lb, 2-2-3
Cuyamaca Larkspur
Downingia concolor vas. brevwr C2 SE List lB, 3-3-3
Cuyamaca Lake Downingia
Ddeya brevifolia c1 SE List lB, 3-3-3
Short-leaved Dudleya
Dudleya multicaulis c2 None List lB, 1-2-3
Many-stemmed Dudleya
Dudleya varkgata c2 None List 4, 1-2-2
Variegated Dudleya
DudEeya vircida c1 None List lB, 3-2-3
Sticky Dudleya
ErVngium aristulatum var. parishii c2 SE List lB, 1-3-2
San Diego Button-celery
1
I
1
I
I
I
1
R
I
I
I
I
1
1
I
I
1
I
Ferocactus acanthodes c2 None List 4, ? 1 California Barrel Cactus
Ferocactus viridescens c2 None List 2, 1
San Diego Barrel Cactus
Fremontodendron mexicanum c2 Rare List lB,
Mexican Flannelbush
Galium angustifolium ssp. borregoense a Rare List lB,
. Borrego Bedstraw
Githopsis dipa ssp. jilicaulk c2 None List lB,
Mission Canyon Bluecup
Hazardia orcuttii c2 None List lB,
Orcutt’s Hazardia
Hemuonia conjugens c2 SE List lB,
Otay Tarplant
Hemuonia floribunda c2 None List lB,
Tecate Tarplant
Heuchera brevistaminea c2 None List lB,
Laguna Mtns. Alumroot
Lepechinia cardwphylla c2 None List lB,
Heart-leaved Pitcher Sage
Lepechinia ganderi c2 None List lB,
Gander’s Pitcher-sage
Lepidium jlavum var. felipense c2 None List lB, :
Borrego Peppergrass
Lesshgia glandulifea var. tomeneosa c2 None List lB, 1
Warner Springs Lessingia
Lilium panyi var. panyi c2 None List 4, 1-
Lemon Lily
Limnanthes gracilis var. pankhii c2 SE List lB, :
Parish’s Meadowfoam
Linanthus orcuttii c2 None List lB, 2
Orcutt’s Linanthus
Lupinus mubitus var. medius c2 None List lB, 2
Mountain Springs Bush Lupine
Machaeranthera asterodes var. lagunensis c2 Rare List lB, 3-3-3
Laguna Mtns. Aster
c1 SE List lB, 3-3-3 Mahonia nevinu
Nevin’s Barberq
List 4, 1-1-2 None Mimuius aridus c2
Low Bush Monkey Flower
Monardella hypoleuca var. lanata c2 None List lB, 3-1-2
Felt-leaved Monardella
Monardella linoides spp. viminea c2 SE List lB, 2-3-2
Willowy Monardella
Monardella nana ssp. leptosiphon c2 None List lB, 3-2-3
San Felipe Monardella
Mudla cievelandii c2 None List 1B, 2-2-2
San Diego Goldenstar
Myosums minimus var. apus c2 None List 3, 2-3-2
Little Mousetail
List lB, 2-3-2 None Navarretia fossah c2
San Diego (Ditch) Navarettia
Nolina interrata c1 SE List lB, 3-3-2
Dehesa Nolina
Opuntia panyi var. seTentina c2 None List lB, 3-3-2
Snake Cholla
Opuntiu wigginsu c2 None List lB, 3-1-2
Wiggins’ Cholla
Orcuttia caiifomica c1 SE List lB, 2-3-2
California Orcutt Grass
Orobanche parish% ssp. brachyloba c2 None List lB, 2-2-2
Short-lobed Broomrape
Orthocapus laswrhynci5us c2 None List lB, 1-2-3
San Bernardino Mtns. Owls-clover
Perideridia gairdneri ssp. gairdnea’ c2 None List 1B, 1-2-3
Gairdner’s Yampah
Pinus torreyana ssp. torreyana c2 None List lB, 3-2-3
Torrey Pine
1
List lB, 2. Poa atropurpurea c1 None 1 San Bernardino Blue Grass
I San Diego Mesa Mint
Pogogyne abramsu FE SE List lB, 2
List lB, 3 Pogogyne nudiuscuia Cl SE
Otay Mesa Mint
Ribes canthariforme c2 None List lB, 3
1
1
I
1
4
I
1
I
I
t
0
1
1
I
I
Moreno Currant
Rorippa gambeilu c2 None List lB, C
List lB, :
Gambel’s Water Cress
Rubus glaucifoiius var. gande~ c2 None
Salvia eremostachya c2 None List 4, 1-
Cuyamaca Raspberry
Desert Sage
Senecw ganderi c2 Rare List lB,
Solanum benudobaturn c2 None List lB,
Gander’s Butterweed
Narrow-leaved Nightshade
Tetracoccus dwkus c2 None List lB,
Parry’s Tetracoccus
Xylorhua orcutrii c2 None List IB,
Qrcutt’s Woody Aster
* California Native Plant Society 1988
List of Suecies Designations
1B:
3:
2:
Species is rare or endangered in California and clsewhere.
Plants about which more information is needed.
Rare or endangered in California, more common elsewhere. 1 4 Plants of limited distribution (a watch list).
- Note: Plants on CNPS list 1B meet CDFG criteria for Rare of Endangered Listing.
R-E-D Code
R- (Rarity)
1 - Rare, but found in sufficient numbers and distributed widely enough that the potential for extinction or extirpation is low at this time.
Occurrence confined to several populations or one extended population.
Occurrence limited to one or a few highly remitted populations, or present in such small numbers that it is seldom reported.
2 -
3 -
E - (Endangerment)
1 - Not endangered
2 -
3 -
Endangered in a portion of its range
Endangered throughout its range
D - (Distribution)
1 ..
2 - Rare outside California
3 - Endemic to California
More or less widespread outside California
I
APPENDIX
ENVIRONMENTAL IMPACT REP
AND C)THER DOCUM
CONSU
/
BIOLOGICAL &SOURCES AND HABITAT ANALYSIS
in support ofthe ClTY OF CAWBAD HABITAT MANAGEMENT PLAN
\
I
I
1
I
1
1
1
0
I
I
1
1
I
I
I
I
R
I
1
Agua Hedionda EIR (329)
Alanda Project EIR (83-5)
Alanda Project EIR (83-5, Part 11)
Anderson EIR (81-10)
Airport Business Center EIR (81-6)
Arroyo La Costa Master Plan EIR (86-2)
Batiquitos Lagoon EIR (84-3)
Batiquitos Pointe EIR (82-4)
Bressi Ranch EIR (83-10)
Buena Vista Park Plaza EIR (82-5)
Calavera EIR (403)
Camino Hills EIR (83-9)
Carlsbad Highlands EIR (80-8)
Carlsbad Highlands EIR (80-8, Supplemental EIR)
Carlsbad Land Investors EIR (83-8)
Carlsbad Oaks (81-4)
City Operations Center EIR (82-1)
Coast Waste Management EIR (84-1)
Cannon Road Reach 1 EIR (87-1)
Del Mar Financial EIR (83-1, General Information)
Evans Point EIR (85-3)
Hosp Grove EIR (86-4)
HPI Development EIR (83-2)
Hunt Properties EIR (83-2, DEIR General Plan)
Hunt Properties EIR (83-2, Annexation of City of Carlsbad)
Huntington Palomar Project EIR (81-9)
Kelly Ranch EIR (83-4)
La Costa Northeast EIR (149) La Costa Vale EIR (35)
Lake Calavera EIR (89-3)
Macario Canyon Park EIR (80-9)
Occidental Land Inc. EIR (81-1)
Poinsettia Lane EIR (82-6)
Pointe San Malo Condominium EIR (80-4)
Rancho Carillo EIR (80-7)
Rancho Del Cerro EIR (85-2)
Rancho La Costa EIR (114)
Ranch Santa Fe Road EIR (91-1)
Robert’s Group Project EIR (83-7)
Robertson Ranch EIR (81-7)
Royal Palms EIR (85-5)
Santa Fe Glens EIR (276)
Santa Fe Knolls Preliminary Environmental Informa tion (85-5)
Seabluff EIR (81-8)
Seawall EIR (84-2)
ShermadSouthers EIR (81-5)
Stagecoach Park EIR (84-5)
Telescope Point EIR (81-2)
Windsong Shores Focus EIR (83-3)
Wooley Annexation EIR (82-3)