HomeMy WebLinkAboutCT 97-13; Carlsbad Oaks North; Tentative Map (CT) (8)I
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. ANALYSIS OE BIOLOGICAL IMPACTS
• AND CONSERVATION MEASURES
m for
1 CARLSBAD OAKS NORTH BUSINESS PARK
I City of Carlsbad, San Diego County, California
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• Prepared for:
I TECI1BILT, INC.
P.O. Box 80036
San Diego, California 92138
• Attention: Ted Chang
Prepared by:
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• A California Corporation
• 605 Third Street
f Encinitas, California 92024
Contact: Harold A. Wier
Tel. (760) 942-5U7
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§JAN 0 8 1998
CITY OF CARLSFiDecember 1997 PLANJWG DEFT
&ASSOCIATES
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Analysis of Biological Impacts fit Conservation Measures
Carlsbad Oaks North Business Park
TABLE Of CONTENTS
Section Page No.
1.0 INTRODUCTION 1
2.0 ANTICIPATED PROJECT IMPACTS ... 2
2.1 Direct Impacts 3
2.1.1 Vegetation Communities 3
2.1.2 Sensitive Plants 4
2.1.3 Sensitive Animals 4
2.1.4 Habitat linkages/Movement Corridors 5
2.2 Indirect Impacts 6
2.2.1 Vegetation Communities 6
2.2.2 Sensitive Plants 6
2.2.3 Sensitive Wildlife 6
2.2.4 Habitat linkages/Movement Corridors 7
3.0 ANALYSIS OF SIGNIFICANCE 7
3.1 Explanation of Findings of Significance 7
3.2 Vegetation Communities 8
3.2.1 Coastal Sage Scrub 9
3.2.2 Southern Mixed Chaparral 9
3.2.3 Scrub Oak Chaparral 9
3.2.4 Coast Live Oak Woodland 10
3.2.5 Valley Needlegrass Grassland 10
3.2.6 Southern Willow Scrub 10
3.2.7 Freshwater Marsh/Disturbed Southern Willow Scrub 10
3.2.8 Southern Coast live Oak Riparian Forest 10
3.2.9 Coastal and Valley Freshwater Marsh 11
3.2.10 Cismontane Alkali Marsh 11
3.2.11 Open Water 11
3.2.12 Non-native (Annual) Grassland 11
3.2.13 Ornamental Plantings/Revegetation 11
3.2.14 Disturbed Habitat 12
3.3 Sensitive Plants 12
3.4 Sensitive Wildlife 13
3.5 Habitat linkages/Wildlife Corridors 13
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Analysis of Biological Impacts GC Conservation Measures
Carlsbad Oaks North Business Park
TABLE Of CONTENTS
Section
4.0 CONSERVATION AND MITIGATION MEASURES
4.1 Vegetation Communities
4.1.1 Coastal Sage Scrub/Revegetation
4.1.2 Coast Live Oak Woodland
4.1.3 Southern Willow Scrub
4.2 Sensitive Plant Species
4.3 Sensitive Wildlife Species
4.4 Habitat Linkages/Wildlife Corridors
Page No.
13
15
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LIST Or TABLES
Table 1
Table 2
Table 3
Table 4
Existing, Impacted and Preserved Habitat Acreage 3
Impacts to Sensitive Plant Species 4
Impacts to Sensitive Animal Species 4
Comparison of Direct Impacts and Open Space (Acres) 12
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Analysis of Biological Impacts 6C Conservation Measures
Carlsbad Oaks North Business Park
1.0 INTRODUCTION
A biological survey of the 414-acre Carlsbad Oaks North Business Park property situated in the east-
central portion of the City of Carlsbad, San Diego County, California was conducted by Dudek &
Associates, Inc. in 1996-1997 (Existing Conditions/Biological Resources and Wetland Delineation Report
for Carlsbad Oaks North Business Park, City of Carlsbad, San Diego County, California; 11/25/97,33 pp.).
Topographically, the site is extremely heterogeneous, varying from about 165 to 545 feet above mean
sea level. Most of the northern portion of the site is represented by a pair of large hills; a broad
riparian drainage traverses the southern half of the site in a roughly east-west direction and a broad
swath of riparian habitat associated with Agua Hedionda Creek cuts across the northwestern corner
of the site. Portions of the southern half of the site have been farmed historically. Based on species
composition and general physiognomy, ten plant communities or habitat types were identified
onsite: coastal sage scrub (42.3 acres), disturbed coastal sage scrub (7.1 acres), coyotebrush scrub (4.6
acres), southern mixed chaparral (212.9 acres), scrub oak chaparral (18.5 acres), coast live oak
woodland (5.0 acres), southern willow scrub (9.8 acres), southern coast live oak riparian forest (26.3
acres), coastal and Valley freshwater marsh (1.3 acres), cismontane alkali marsh (0.7 acre), and open
water (0.1 acre). In addition, three altered or non-native habitat types are present: non-native
(annual) grassland/ruderal (51.4 acres), ornamental plantings/revegetation (10.1 acres), and disturbed
habitat (7.3 acres).
One species of plant listed as endangered by the California Department of Fish and Game (CDFG)
and proposed for listing as endangered by the U.S. Fish and Wildlife Service (USFWS) was detected:
thread-leaved brodiaea (Brodiaea filifolia}. Eight additional plant species considered sensitive by
various resource agencies also were observed: California adolphia (Adolf hia californica), San Diego
sagewort (Artemisia palmeri}, summer-holly (Comarostaphylis diversifolia], western dichondra
(Dichondra occidentalis], southwestern spiny rush (Juncus acutus var. leopoldif), San Diego golden-stars
(Muilla develandii), Nuttall's scrub oak (Quercus dumosa], and ashy spike-moss (Selaginella cinerascens}.
No animal species listed as rare, threatened, or endangered by the USFWS or CDFG were observed
onsite during focused surveys. Four species formerly recognized as Category 2 candidates for listing
were observed: southern California rufous-crowned sparrow (Aimophila ruficeps canescens], northern
red-diamond rattlesnake (Crotalus ruber rubei), orange-throated whiptail lizard (Cnemidophorus
hyperythrus}, and San Diego horned lizard (Phrynosoma coronatum blainvillei]. Six species recognized
as species of special concern by the CDFG also have been documented from the site either historically
or during recent focused surveys: golden eagle (Aquila chrysaetos), white-tailed kite (Elanus caeruleus),
Cooper's hawk (Accipiter cooperi), sharp-shinned hawk (Accipiter striatus), northern harrier (Circus
cyaneus], and burrowing owl (Athene cunicularia].
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
The majority of the site supports southern mixed chaparral, •which is not recognized as a "sensitive"
community by state and federal resource agencies. However, other native communities onsite,
including coastal sage scrub, scrub oak chaparral, coast live oak woodland, and a variety of wetland
habitats, are considered sensitive. The highest value habitats include the oak riparian forest and
southern willow scrub which form a portion of a larger, regional habitat linkage/corridor extending
offsite to the west and east of the property.
2.0 ANTICIPATED PROJECT IMPACTS
This section addresses direct and indirect impacts to biological resources that would result from
implementation of the proposed project.
Direct impacts were quantified by overlaying the limits of project grading and the brush
management zones on the biological resources map of the site (see map pocket). Offsite impacts that
would result from grading for the Faraday Avenue extension project are addressed in a separate
document (Dudek & Associates, Inc. November 1997. Biological Resources Report and Impact Analysis
for the Faraday Avenue Extension, City of Carlsbad. Prepared for Techbilt, Inc.). For the purposes of this
assessment, all biological resources within the limits of grading for the project and the brush
management zones were considered 100% lost.
Indirect Impacts are very difficult to identify and quantify but are presumed to occur. They
primarily result from adverse "edge effects;" either short-term indirect impacts related to construction
or long-term, chronic indirect impacts associated •with location of urban development in proximity
to biological resources within natural open space. During construction of the project, short-term
indirect impacts may include dust and noise which could disrupt habitat and species vitality
temporarily, and construction related soil erosion and runoff. The Carlsbad Grading and Erosion
Control Ordinance has strict requirements dealing with dust, noise and erosion that •will need to be
adhered to during development. Special requirements such as not allowing construction equipment
or staging areas to be near sensitive habitat areas should be incorporated in the project conditions of
approval. Long-term indirect impacts of a generic development project may include unwanted effects
of lighting, noise, runoff, exotic plant invasion, encouragement of exotic animals, soil erosion, fire
and changes to wetland hydrology. The Grading and Erosion Control Ordinance purposely
emphasizes protecting the natural environment including native plant communities. The new slopes
adjacent to natural areas will be revegetated with appropriate species and strict erosion control
measures implemented. The proposed project is industrial, a land use that conservation biologists
acknowledge cause less severe indirect effects. An industrial project is characterized by a general
absence of pet animals and children that are associated with a residential development, limited hours
of operation, greater control of lighting and less noise at least during the evenings and on weekends.
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
2.1 Direct Impacts
2.1.1 Vegetation Communities
Implementation of the proposed project would result in the direct and complete loss of the vegetation
community acreages presented in Table 1. The project would develop 234 acres and leave 180 acres
in open space. In addition, a portion of the developed area (approximately 28.2 acres) would be
external slopes, between the development and open space, that could be vegetated with a plant
palette compatible with the adjacent preserved habitat.
Table 1
Existing, Impacted and Preserved Habitat Acreage
Habitat typef PI ant Community
Coastal sage scrub
Disturbed coastal sage scrub
Coyotebrush scrub
Southern mixed chaparral
Disturbed southern mixed chaparral
Scrub oak chaparral
Coast five oak woodland
Valley needlegrass grassland
Non-native (annual) grassland
Subtotal, Natural Uplands
Southern willow scrub
Freshwater marsh/disturbed southern willow scrub
Southern coast live oak riparian forest
Coastal and Valley freshwater marsh
Cismontane alkali marsh
Open water
Subtotal, Wetlands
Subtotal, All Natural Habitats
Ornamental plantings/revegetation
Disturbed habitat
Subtotal, Disturbed Types
tetal
Existing
42.3
7.1
4.6
212.9
14.2
18.5
5.0
1.1
51.4
357.1
9.8
1.4
26.3
1.3
0.7
0.1
39.fi
396.7
10.1
7.3
17.4
4l4,i
Grading
Ac
31.6
4.3
3.0
162.5
3.5
6.9
1.9
0.5
12.2
226,4
0.5
0.0
0.0
0.0
0.0
0.0
0.5
226.9
1.9
5.1
7.0
nu
%
75%
61%
65%
76%
25%
37%
38%
50%
24%
63%
5%
3%
0%
0%
0%
0%
1%
57%
19%
71%
40%
WA
Open Space
Ac
10.6
2.8
1.6
50.4
10.7
11.6
3.1
0.5
39.2
130,5
9.3
1.4
26.3
1.3
0.7
0.1
39.1
169.6
8.2
2.1
10.3
179,9 I
%
25%
39%
35%
24%
75%
63%
62%
50%
76%
37%
95%
97%
100%
100%
100%
100%
99%
43%
81%
29%
59%
4*%
DUDEK
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_ Analysis of Biological Impacts SC Conservation Measures
^ Carlsbad Oaks North Business Park
I 2.1.2 Sensitive Plants
• Implementation of the proposed project would result in the direct loss of the locations and
™ individuals of sensitive plant species presented in Table 2.
| Table 2
Impacts to Sensitive Plant Species
iPlanl Spscies
| California adolphia (Adolphia califomica)
San Diego sagewort (Artemisia palmeri]
VI Thread-leaf brodiaea (Brodiaea filifolia]
^ Summer-holly (Comarostaphylis diversifolia}
m Western dichondra (Dichondra occidentalis)
1 Southwestern spiny rush (Juncus acutus}
San Diego golden-stars (Muilla Cleveland!!}
I Ashy spike-moss (Selaginella cinerascens}
™ 2.1.3 Sensitive Animals
Existing Population Direct Impacts
{Point localities or tetfividuaJe} {Point loc&Mes or Jtjditf idueJs)
21 3 individuals
2 points
6 individuals
6 points
1 point
21 points
1 point
85 points
38 individuals
0 point
0 individual
2 points
0 point
0 point
1 point
77 points
• Implementation of the proposed project would result in the direct and complete loss of the locations
of sensitive animal species presented in Table 3.
1 Table 3
Impacts to Sensitive Animal Species
I• :
I Awtft^M v|)$&Hf$
Orange-throated whiptail (Cnemidophorus hyperythrus
m San Diego horned lizard (Phrynosama coronatum}
White-tailed kite (Elamis caeruleus}
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; &J$#«a Pofrti&tten
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(Pwirt iwalitiesj
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Analysis of Biological Impacts 6C Conservation Measures
Carlsbad Oaks North Business Park
2.1.4 Habitat Linkages/Movement Corridors
The property is located in the eastern portion of the City of Carlsbad, essentially at the junction of
the cities of Carlsbad, Vista and San Marcos, in the northwestern part of the County of San Diego.
It is located within two major, overlapping habitat conservation planning areas, i.e.,: the larger
North County Wildlife Forum Multiple Habitat Conservation Plan (MHCP) area, which includes all
of the smaller Carlsbad Habitat Management Plan (HMP) area. Both plans are in development at this
time.
Because the Oceanside-Carlsbad-Vista-San Marcos area appears to offer limited opportunities to
contribute substantial amounts of land to the regional habitat conservation goals of the wildlife
agencies, the few remaining relatively large blocks of unimproved land such as the Carlsbad Oaks
North property (Carlsbad Oaks is 414 acres and is contiguous with other natural lands) have been
viewed by the resource agencies as increasingly important to completing an adequate habitat reserve
system in the north county.
The proposed Carlsbad Oaks North Business Park development is important to the fate of two local
habitat linkages or wildlife corridors, i.e., the Agua Hedionda Creek drainage along the north side of
the site, which connects Agua Hedionda Lagoon to the University of California Dawson-Los Monos
Reserve; and the unnamed creek that flows through the southern part of the site east to west, which
connects habitats around the creek confluence to the Carlsbad Raceway area (Figure 1}. The Agua
Hedionda Creek system transects the northwestern property corner. High quality riparian habitat
exists in this area and continues off site in both directions. Ultimately, despite the value of the Agua
Hedionda Creek system locally, connections are tenuous offsite near the Vista County of San Diego
boundary, and very poor within the County area south of Vista and north of San Marcos. The
unnamed creek is a local drainage that has its headwaters in a disturbed/developed area east of the
Carlsbad Raceway in the City of Vista. Although the onsite contribution is significant, the drainage
system in total is a poor regional corridor connecting weakly to Carrillo Ranch, and ultimately
Meadowlark Estates and University Commons in the City of San Marcos.
Because wildlife probably use the entire site for movement, implementation of the proposed project
would result in some reduction of potential wildlife movement opportunities. Although no specific
movement corridors on the project site were identified through field observations, the site is used by
large mammals, including mule deer, coyote, and bobcat. These species tend to use physiographic
"paths of least resistance" such as drainage and canyon bottoms, dirt roads, trails, and ridge lines.
The project design preserves Agua Hedionda Creek and the southern drainage, including adjacent
natural uplands in configurations that are consistent with maintaining wildlife movement. Corridor
widths are consistent with regional guidelines: there is only one crossing of any of the major creeks,
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
and the effects of this crossing are reduced by an 8-foot by 30-foot soft-bottom culvert; corridors
onsite generally are several hundred feet wide, and at the east end are up to 2,400 feet wide; offsite
the corridors are 1,000 and 2;000 feet or more wide; and, areas where the corridors are short and
physiographic relief ameliorates potential adverse effects.
2.2 Indirect Impacts
2.2.1 Vegetation Communities
Indirect impacts to vegetation communities primarily would result from adverse "edge effects" as
cited above. During construction of the project, edge effects may include dust which could disrupt
plant vitality in the short term or construction related soil erosion and runoff. Strict adherence to
the Carlsbad Grading and Erosion Control Ordinance will be required. Long-term indirect impacts
on vegetation communities most likely would be less than with a comparable sized residential
project, and are reduced by certain elements of the project design. Indirect effects are expected to
include invasion of natural habitats by exotic landscape species, alteration of the natural fire regime,
and exposure to urban pollutants.
2.2.2 Sensitive Plants
Most of the indirect impacts to vegetation communities cited above can also affect sensitive plants.
During construction of the project, indirect effects may include dust which could disrupt plant
vitality in the short term or construction related soil erosion and runoff. Strict adherence to the
Carlsbad Grading and Erosion Control Ordinance will be required. Long-term indirect impacts on
sensitive plant species also most likely would be less than with a comparable sized residential proj ect,
and are reduced by certain elements of the project design. Indirect effects are expected to include
invasion of natural habitats by exotic landscape species, alteration of the natural fire regime, and
exposure to urban pollutants.
2.2.3 Sensitive Wildlife
Most of the indirect impacts to vegetation communities and sensitive plants cited above can also
affect sensitive wildlife. However, additional indirect impacts on wildlife are possible. During
construction of the project, indirect effects may include dust and noise which could disrupt normal
behaviors crucial for foraging and breeding. Location of construction staging areas away from natural
areas will help reduce wildlife impacts. Long-term indirect impacts on sensitive animal species also
most likely would be less than with a comparable sized residential proj ect; and are reduced by certain
elements of the project design. Indirect effects are expected to include encouragement of exotic
animals due to increased irrigation and food supplies, adverse effects of lighting which can be directed
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
away from natural areas and noise, and exposure to urban pollutants. Some sensitive wildlife species
are believed to require large tracts of relatively undisturbed habitat (i.e., "interior species") and
populations may decrease or disappear along the edges of habitat. Other species are nest-parasitized
by the brown-headed cowbird, a species that is more likely to occur along urban wildlife habitat
interfaces.
2.2.4 Habitat Linkages/Movement Corridors
In the context of urban development, the project is expected to have an adverse indirect effect on the
function of habitat linkages and movement corridors. However, as mentioned above, the nature of
the project as an industrial development reduces these potential effects because, typically, industrial
areas do not operate at night, or on weekends or holidays, whereas residential areas always are sites
of human activity. Industrial areas also do not generate the same types of activities associated with
adverse edge effects, including those of children and pets. The project will permanently define open
space areas and also implement protective measures for future breeding development onsite.
Adverse edge effects caused by implementation of the project could indirect affect habitat linkages
and movement corridors that are part of the project. Narrowing and constraining of habitat linkages
and movement corridors will bring wildlife into more frequent contact with humans, domestic pets,
and other human-generated sources of disturbance (litter, exotic species, urban pollutants, etc.).
Wildlife mortality because of collisions with vehicles will become more frequent. Lighting and noise
may inhibit movement by nocturnal species but will be minimized by appropriate mitigation
measures such as directional lighting and Carlsbad building codes that restrict outdoor
manufacturing.
3.0 ANALYSIS OF SIGNIFICANCE
3.1 Explanation of Findings of Significance
Impacts to native habitats, sensitive plants, and sensitive wildlife species must be quantified and
analyzed to determine whether such impacts are significant under the California Environmental
Quality Act (CEQA). CEQA Guidelines section 15064(b) states that an ironclad definition of
"significant" effect is not possible because the significance of an activity may vary with the setting.
Appendix G of the Guidelines, however, does provide "examples of consequences which may be
deemed to be a significant effect on the environment" (Guidelines section 15064(e)). These effects
include substantial effects on rare or endangered species of animal or plant or the habitat of the
species. Guidelines section 15065(a) also is helpful in defining whether a project may have "a
significant effect on the environment." Under that section, a proposed project may have a significant
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• The following sections describe the impacts to each component vegetation type.
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
effect on the environment if the project has the potential to: (1) substantially degrade the quality
of the environment; (2) substantially reduce the habitat of a fish or wildlife species; (3) cause a fish
or wildlife population to drop below self-sustaining levels; (4) threaten to eKminate a plant or animal
community; (5) reduce the number or restrict the range of a rare or endangered plant or animal; or
(6) eliminate important examples of the major period of California history or prehistory.
The evaluation of whether or not ah impact to a particular biological resource is significant must
consider both the resource itself and the role of that resource in a regional context. Substantial
impacts are those that contribute to, or result in; permanent loss of an important resource, such as
a population of a rare plant or animal. Impacts may be important locally because they result in an
adverse alteration of existing site conditions, but considered not significant because they do not
contribute substantially to the permanent loss of that resource regionally. The severity of an impact
is the primary determinant of whether or not that impact can be mitigated to a level below
significant.
3.2 Vegetation Communities
For the purpose of analyzing the significance of impacts to vegetation communities, impacts resulting
from grading of the project and brush management were considered as direct impacts. Grading and
brush management would affect a total of 234 acres (57%) of the 414-acre site. More meaningful to
habitat analysis is the fact that of this total, 227 acres is considered natural vegetation, albeit some
of it disturbed in the past.
Typically, an impact analysis is conducted on each individual habitat type present, and a
determination of significance is made for each. This is all the more expected and appropriate when
dealing with "regulated" plant communities such as wetlands and coastal sage scrub. However, this
approach is less helpful under the current conditions of this project because the origin, future via
succession, and biological value of the mapped coastal sage scrub, normally considered highly
sensitive, is questionable. Coastal sage scrub does not represent the intact natural habitat on the
property and its preservation would not capture the site's biodiversity, or contribute significantly to
regional biodiversity. Other habitats are more species-rich and represent superior values for long-term
conservation.
However, because of the site's large size and extent of intact habitat, the proposed project would
have an important effect on biological resources by reducing the amount of available open land to
wildlife and plants.
December 9,1997
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
3.2.1 Coastal Sage Scrub
Implementation of the project would result in direct impacts to 38.9 acres (72%) of the 54 total acres
of coastal sage scrub (including disturbed coastal sage scrub and coyotebrush scrub). Most of the
coastal sage on relatively gentle slopes, particularly the prominent hill in the northwestern part of
the site. Coastal sage scrub-like vegetation is found on the site in such locations because these former
chaparral sites were relatively easy to brush on these forgiving slope gradients. These same slope
gradients facilitate siting of land development opportunities under the current plan.
Coastal sage scrub occupies about 8-10 percent of San Diego County's total area. Hix (1990) indicates
that this community has been reduced by greater than 70 percent of its original coverage, primarily
as a consequence of housing and other urban developments. Because coastal sage scrub is known to
support a variety of sensitive species regionally, and because it has been reduced in acreage
throughout San Diego County, it is considered a sensitive habitat by local, state; and federal agencies.
Loss of 38.9 acres of this habitat therefore is regarded as a significant effect.
3.2.2 Southern Mixed Chaparral
Implementation of the project would result in direct impacts to 162.5 acres or 76% of the 212.9 total
acres of southern mixed chaparral, and 3.5 acres or 25% of the 14.2 acres total of disturbed southern
mixed chaparral. This represents an incremental reduction of a relatively widespread habitat in the
region.
Because southern mixed chaparral is a widespread and common community type in San Diego
County, this impact is not regarded as a significant effect.
3.2.3 Scrub Oak Chaparral
Implementation of the project would result in direct impacts to 6.9 acres or 37% of the 18.5 total
acres of scrub oak chaparral. This habitat is less common certainly than southern mixed or chamise
chaparral, and more common that southern maritime chaparral. It has not been identified as a
sensitive habitat type per se, and its value may be more appropriately analyzed in the context of its
indicator species, itself a recognized sensitive species, i.e., Nuttall's scrub oak (Quercus dumoso).
Because the proposed project preserves a large percentage of the scrub oak chaparral in open space,
this impact is not regarded as a significant effect.
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Analysis of Biological Impacts 6t Conservation Measures
Carlsbad Oaks North Business Park
3.2.4 Coast Live Oak Woodland
Implementation of the project would result in direct impacts to 1.9 acres or 38% of the total 5.0 acres
of coast live oak woodland. Coast live oak woodland is considered a sensitive and highly productive
habitat for wildlife. Therefore, loss of coast live oak woodland is regarded as a significant effect.
3.2.5 Valley Needlegrass Grassland
Implementation of the project would result in direct impacts to 0.5 acre or 50% of the 1.0 total acre
of Valley needlegrass grassland. Valley needlegrass grassland is a sensitive habitat in southern
California because of loss to agriculture and urbanization. This habitat is designated as rare by the
CNDDB and CDFG. No sensitive species -were found to be associated with Valley needlegrass
grassland on the property and it seems very unlikely that any sensitive wildlife would occur there
(e.g., grasshopper sparrow) because of the small sizes of the grassland patches.
The loss of an exceedingly small amount of this habitat is not as a significant effect. An equal
amount of this habitat will be retained onsite in open space.
3.2.6 Southern Willow Scrub
Implementation of the project would result in direct impacts to 0.5 acre or 5% of the total 9.8 acres
of southern willow scrub. This area of southern willow scrub is located at the crossing of the main
riparian area by Faraday Avenue onsite. Although the impact is small, the southern willow scrub
onsite would be regulated as a wetland under Section 404 of the Clean Water Act and Section 1600-
1603 of the California Fish and Game Code. Although a substantial amount of southern willow scrub
would be protected on the site in open space, and its continuity through the site would be retained,
impacts routinely are considered significant.
3.2.7 Freshwater Marsh/Disturbed Southern Willow Scrub
Implementation of the project would result in no direct impacts to the 1.4 acres of freshwater
marsh/disturbed southern willow scrub.
3.2.8 Southern Coast Live Oak Riparian Forest
Implementation of the project would result in no direct impacts to the 26.3 acres of southern coast
live oak riparian forest. Southern coast live oak riparian forest is considered a rare habitat by the
CNDDB and CDFG and would be regulated as a wetland by Section 404 of the Clean Water Act and
Section 1600-1603 of the California Fish and Game Code.
December 9,1997 10
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Analysis of Biological Impacts 8C Conservation Measures
Carlsbad Oaks North Business Park
3.2.9 Coastal and Valley Freshwater Marsh
Implementation of the project •would result in no impacts to the 1.3 acres of freshwater marsh.
Freshwater marsh is considered a rare habitat by the CNDDB and CDFG and would be regulated as
a wetland by Section 404 of the Clean Water Act and Section 1600-1603 of the California Fish and
Game Code.
3.2.10 Cismontane Alkali Marsh
Implementation of the project would result in no impacts to the 0.7 acre of cismontane alkali.
Cismontane alkali marsh is considered a rare habitat by the CNDDB and CDFG and would be
regulated asa wetland by Section 404 of the Clean Water Act and Section 1600-1603 of the California
Fish and Game Code.
3.2.11 Open Water
Implementation of the proj ect would result in no impacts to the 0.1 acre of open water. Open water
on the site would be regulated as a wetland by Section 404 of the Clean Water Act and Section 1600-
1603 of the California Fish and Game Code.
3.2.12 Non-native [Annual] Grassland
Implementation of the project would result in direct impacts to 12.2 acres or 24% of the 51.4 total
acres of annual grassland. Annual grassland may provide foraging habitat for raptors and other
sensitive species.
Although it is a habitat that provides resources for sensitive species, the loss of 12.2 acres of annual
grassland is not considered a significant effect. No sensitive animal or plant species were specifically
identified within this habitat, and the amount of loss is relatively small, but botanically this habitat
has very poor value in its existing condition. Annual grassland on proper soils potentially is restorable
to a native plant community.
3.2.13 Ornamental Plantings/Revegetation
Implementation of the project would result in direct impacts to 1.9 acres or 19% of the total 75.1
acres of ornamental plantings/revegetation. Typically this habitat has poor habitat value because of
the predominance of alien plant species, how/ever substantial trees may provide important perch and
nest sites for raptors and other birds. This habitat only would be considered important if heavily
used by native wildlife. The presence of many native trees in the onsite riparian and oak woodland
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
areas renders the ornamental areas of much less relative importance. The loss of this habitat is not
regarded as a significant effect.
3.2.14 Disturbed Habitat
Implementation of the project would result in direct impacts to 5.1 acres or 71% of 7.3 total acres of
disturbed habitat. Because disturbed habitat lacks native vegetation and habitat value, impacts to
this land cover are not regarded as a significant effect.
3.3 Sensitive Plants
Information on direct impacts to the nine sensitive plant species that were documented from the site
is presented in Table 4-
Table 4
Comparison of Direct Impacts and Open Space (Acres)
ttabrtai TypefPlant Community
Coastal sage scrub
Disturbed coastal sage scrub
Coyotebrush scrub
Southern mixed chaparral
Disturbed southern mixed chaparral
Scrub oak chaparral
Coast live oak woodland
Valley needlegrass grassland
Non-native (annual) grassland
Subtotal, Natural Uplands
Southern willow scrub
Freshwater marsh/disturbed southern willow scrub
Southern coast live oak riparian forest
Coastal and Valley freshwater marsh
Cismontane alkali marsh
Open water
Subtotal, Wetlands
Subtotal, All Natural Habitats
Ornamental plantings/revegetation
Disturbed habitat
Subtotal, Disturbed Types
; Toial
Grading impacts
31.6
4.3
3.0
162.5
3.5
6.9
1.9
0.5
12.2
226,4
0.5
0.0
0.0
0.0
0.0
0.0
D.5
226.9
1.9
5.1
7.0
233.i
Open Space
10.6
2.8
1.6
50.4
10.7
11.6
3.1
0.5
39.2
T30.5
9.3
1.4
26.3
1.3
0.7
0.1
39.1
169.6
8.2
2.1
10.3
I79J
Difference
(21.0)
(1.5)
(1.4)
(112.1)
7.2
4.7
1.2
0.0
27
(95.9)
8.8
1.4
26.3
1.3
0.7
0.1
38.6
(57.3)
6.3
(3.0)
3.3
®W
() indicates a net open space deficit.
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Analysis of Biological Impacts SC Conservation Measures
Carlsbad Oaks North Business Park
Impacts to sensitive plant species are regarded as less than significant. Based on the available
mapping, there are no known impacts to: San Diego sagewort, -western dichondra, southwestern
spiny rush or the endangered thread-leaf brodiaea. There are only two known point localities of
summer-holly; representing fewer than 10 individuals, that will be impacted. The one known locality
of San Diego golden-stars will be impacted. Although a substantial population of California adolphia
exists on the property; only approximately 38 plants will be impacted whereas approximately 213
individuals will be included within open space (Both the impacted and preserved numbers probably
are underestimates; the proportion is useful in judging impacts.). Most (77 of 85) of the mapped
localities of ashy spike-moss will be impacted, however a few will remain in the western portion of
the site, and it is likely that the species is a bit more widespread in open space than indicated by the
mapping. A total of 6.9 acres of scrub oak chaparral will be developed, containing an estimated
hundreds of individual Nuttall's scrub oak plants, and 11.6 acres of scrub oak chaparral will be
conserved, also containing hundreds of plants in open space.
3.4 Sensitive Wildlife
Impacts to orange-throated whiptail, San Diego horned lizard and white-tailed kite, are regarded as
less than or not significant for at least one of the following reasons: all or most individuals would,
be conserved onsite; substantial habitat for the species would be conserved onsite; its habitat is still
relatively abundant in the region; and/or the species is still relatively common within its range. The
project would not have a substantial adverse effect on the viability and survival of these species in
the wild. These species include: white-tailed kite (potential nest and roost trees conserved onsite),
orange-throated whiptail (substantial habitat conserved onsite and populations relatively common
of f site), and San Diego horned lizard (substantial habitat conserved onsite and populations relatively
common off site).
3.5 Habitat Linkages/Wildlife Corridors
Direct and indirect impacts to habitat linkages and wildlife corridors are regarded as less than
significant because the existing major opportunities for wildlife movement will be retained.
4.0 CONSERVATION AND MITIGATION MEASURES
During discussions regarding how the Carlsbad Oaks North Business Park project contributes to the
Carlsbad Habitat Management Plan and the Multiple Habitat Management Plan, the U.S. Fish and
Wildlife Service and California Department of Fish and Game indicated that projects in the Multiple
Habitat Conservation Plan (MHCP) area should contribute a minimum of 50% of the property area
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Analysis of Biological Impacts fit Conservation Measures
Carlsbad Oaks North Business Park
as undisturbed open space (i.e., revegetated external slopes will not count numerically toward
mitigation) in a configuration that is effective biologically.
The proposed development would grade 234 acres of the 414-acre site (56.5%), and leave 179.9 acres
unaffected. Of all existing natural habitats, it would grade 227 acres of 396.6 acres (57.2%), and leave
169.6 acres unaffected. Of all existing natural uplands, the project would grade 226.4 acres of the
total 356.9 acres (63.4%) and leave 130.5 unaffected. Of all existing wetlands, the project would
grade or affect directly 0.5 acre of the total 39.1 acres (1.2%), 38.6 acres unaffected. This method of
analysis concludes that the project proposes to develop 54 acres in excess of the 50% target indicated
by the resource agencies. Acquisition of 54 habitat credit acres in an approved mitigation bank would
be necessary to offset the habitat impacts.
The project would conserve very high percentages of the most intact and regionally sensitive
habitats: wetlands (98.8%), and coast live oak woodland (62%). No habitat type would be lost from
the site, and all would remain in ecologically viable configurations.
A typical impact analysis is conducted on a habitat-by-habitat basis, and significance determinations
and in-kind mitigation requirements are made for each plant community type. The following
analysis attempts to look at the overall picture of habitat impacts and mitigation recommendations
in the context of this site's resources and its relationship to the Carlsbad Habitat Management Plan
(HMP) and MHCP.
The following conservation and mitigation measures will reduce significant effects identified above
to a level that is less than significant. These conservation and mitigation measures were developed
in a regional context and provide that Carlsbad Oaks North Business Park will contribute to overall
assembly and conservation of the preserve envisioned in ongoing multiple species planning efforts.
The proposed mitigation package would reduce identified impacts to biological resources to a level
below significant by ensuring that biological resources on the property are conserved in a
configuration that maximizes the potential for continued persistence of sensitive species onsite and
provides connectivity to offsite areas anticipated to be preserved as part of ongoing multiple species
planning efforts. In addition, the project provides an important contribution to regional resource
planning efforts by the contribution of 54 habitat credits (acres) at the resource agency approved
Carlsbad Highlands Mitigation Bank located in the City of Carlsbad. This bank is located less than
one mile from the project site in the northeastern portion of the City of Carlsbad and provides
important habitat, primarily coastal sage scrub, and populations of several sensitive species.
MEEK
|&ASSOCIATES| 953'02_
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I No significant impacts to sensitive plants species were identified and no specific mitigation measures
are recommended. However, the provision of 180 acres of open space, 169.6 acres of which is natural
habitat supporting populations of most (i.e., only one species, San Diego golden stars, would not be
• represented in natural open space upon completion of the project.) of the known onsite sensitive
plant species will contribute to the effective preservation of these species in the wild.
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Analysis of Biological Impacts 6C Conservation Measures
Carlsbad Oaks North Business Park
4.1 Vegetation Communities
4.1.1 Coastal Sage Scrub/Revegetation
Significant impacts to 38.9 acres of coastal sage scrub (including disturbed coastal sage scrub and
coyotebrush scrub) will be mitigated by overall onsite preservation of 180 acres of habitat including
onsite conservation of 15 acres of coastal sage scrub. In addition, approximately 28 acres of graded
external slopes will be planted with a mix of native coastal sage scrub and chaparral species that will
form a buffer between the development and this habitat onsite and provide additional habitat for
coastal sage scrub animals.
4.1.2 Coast Live Oak Woodland
Significant impacts to oak woodland will be mitigated by onsite conservation of 180 acres of land,
including 3.1 acres of oak woodland, and a revegetation program that will establish ten (10) "sleeve"
size seedlings for each mature tree that is impacted by the project.
4.1.3 Southern Willow Scrub
Significant impacts to southern willow scrub will be mitigated by onsite conservation of 180 acres
of land, including 9.3 acres of southern willow scrub, plus restoration of disturbed wetlands onsite
or creation of wetlands onsite at a 3:1 ratio (i.e., 1.5 acres). If onsite creation or restoration is not
practical or is not approved by the resource regulatory agencies (i.e., Corps of Engineers and California
Department of Fish and Game during the respective wetland permit processes), then an alternative
mitigation measure, such as offsite mitigation, will be implemented.
4.2 Sensitive Plant Species
4.3 Sensitive Wildlife Species
No sensitive animal species identified in this report will be subject to significant impacts, and no
specific mitigation measures are recommended. However, the project will provide 180 acres of open
space, 170 acres of which is natural habitat that would support sensitive species populations.
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Analysis of Biological Impacts 6C Conservation Measures
Carlsbad Oaks North Business Park
4.4 Habitat Linkages/Wildlife Corridors
The project accommodates sub-regional connectivity through onsite conservation of 180 acres of
land, 170 acres of which is natural vegetation, including two riparian corridors. At its narrowest, the
southern corridor is 600 feet wide. Widths along this area typically are 800-1000 feet or more, with
significant vertical separation between habitat in the corridor and developed land to the south. A
culvert structure 8 feet high and 30 feet wide would be installed in the creek bed to support the road
crossing, accommodate storm flows and facilitate wildlife movement. The culvert would be of large
enough diameter to allow light through the entire structure and would be designed to include a
natural soft bottom that would further facilitate wildlife use. This is at a potential "pinch-point"
in a natural narrowing of the riparian system, and is also the location where development footprints
constrict the corridor the most. The northern corridor, along Agua Hedionda Creek, ranges in width
between about 1000 feet at the west end, and over 2000 feet at the east end. All of this area exhibits
significant vertical separation that enhances the isolation of the habitats in the preserved area.
Further, the development in the northeastern part of the proposed development will not be visible
from the north side of the ridge along that property line. There are no crossings of this creek system
or corridor.
The configuration minimizes adverse edge effects adjacent to preserved open space in several ways.
Proposed uses primarily are office/industrial, which generally are more regarded as more benign than
residential. External slopes will be revegetated with a plant palette of native species. The
development edge along a significant part of the southern drainage is "single-loaded," meaning there
are no uses south of the roadway. Development edges are smooth, except where necessary to avoid
wetland impacts, thereby reducing the amount of adverse edge. Finally, vertical separation between
the developed areas and the preserved areas is substantial, on the order of hundreds of vertical feet.
This vertical separation enhances the horizontal corridor and preserve widths.
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