3.8-1

3.8 TERRESTRIAL BIOLOGY

3.8.1 Introduction

This section describes existing terrestrial resources of the Point Mugu Sea Range, Point Mugu, SanNicolas Island, and the Sea Range support facility sites on San Miguel, Santa Rosa, and Santa Cruzislands. Terrestrial refers to those species that habitually live on the land or ground surface. Forpurposes of this document, the discussion of terrestrial resources also includes species that spend aportion of their life on land, such as seabirds that may nest on the land but forage and loaf (i.e., rest) onopen water. Detailed background information on terrestrial resources at Point Mugu and San NicolasIsland is presented in the Natural Resources Summary Report (NAWCWPNS Point Mugu 1999).

3.8.1.1 Definition of Resource

For purposes of this document, terrestrial natural resources are defined as flora and fauna and the habitatsthey occupy. Regionally and locally sensitive species (as defined by the USFWS and CDFG) andendemic species (i.e., species native to and restricted to a particular geographic region) are alsoaddressed.

Plant or wildlife species may be designated as sensitive because of their overall rarity, endangerment,unique habitat requirements, and/or restricted distribution. In general, a combination of these factorsleads to a sensitivity designation. Sensitive plant and wildlife species include those listed as threatenedor endangered by the USFWS and CDFG. In addition, plants may be listed by the California NativePlant Society (CNPS) with regard to their rarity, endangerment, and distribution (Skinner and Pavlik1994).

Species that are federally or state-listed are afforded a degree of regulatory protection which entails apermitting process including specific mitigation measures for any allowable (incidental) impacts to thespecies. Species that are proposed to be listed by the USFWS are treated similarly to listed species bythat agency; recommendations of the USFWS, however, are advisory rather than mandatory in the case ofproposed species. A federally listed endangered species is defined as any species, including subspecies,that is “in danger of extinction throughout all or a significant portion of its range.” A federally listedthreatened species is defined as any species “likely to become an endangered species within theforeseeable future throughout all or a significant portion of its range.” “Proposed” endangered orthreatened species are those species for which a proposed regulation has been published in the FederalRegister, but a final rule has not yet been issued. A “Federal Candidate” is any species being consideredby the USFWS for listing as an endangered or threatened species but which is not yet the subject of aproposed rule. Federal Candidates are “taxa for which the USFWS currently has substantial informationon biological vulnerability and threat(s) to support a proposal to list the taxa as endangered orthreatened.” Federally and state-listed threatened and endangered species that are known to occur on theSea Range, Point Mugu, and San Nicolas Island are summarized in Table 3.8-1.

Also included in this high sensitivity category, for the purposes of this report, are species listed by theState of California as endangered, threatened, or rare for which similar definitions apply. A CaliforniaSpecies of Special Concern is a species or subspecies native to California that has become vulnerable toextinction because of declining population levels, limited ranges, or rarity, and may be considered forlisting or for special management and protection measures. Species are placed in this category so issuesrelated to their decline may be addressed during the environmental assessment process.

3.8-2

Table 3.8-1. Federally and State-Listed Sensitive Terrestrial Species Occurring on Sea Range,Point Mugu, and San Nicolas Island

Scientific Name Common Name Status1 Habitat2 Location3

PlantsAstragalus traskiae Trask’s milkvetch CDFG: R COD, sandstone SNICordylanthus maritimusssp. maritimus

Salt marsh bird’s-beak USFWS: E CSM PM

Dithyrea maritima Beach spectacle pod CDFG: T COD SNIEriogonum grande timorum San Nicolas Island buckwheat CDFG: E CS SNIReptiles and AmphibiansXantusia riversiana Island night lizard USFWS: T All terrestrial habitats SNIBirdsPasserculus sandwichensisbeldingi

Belding’s savannah sparrow CDFG: E CSM PM

Charadius alexandrinusssp. nivosus

Western snowy plover USFWS: T Sandy beaches andadjacent coastalstrand

PMSNI

Falco peregrinus anatum American peregrine falcon USFWS: E4

CDFG: EOpen water andterrestrial habitats

PMSNI

Pelecanus occidentalis ssp. californicus

California brown pelican USFWS: ECDFG: E

Open water PMSNI

Rallus longirostrus levipes Light-footed clapper rail USFWS: ECDFG: E

CSM PM

Sterna antillarumssp. browni

California least tern USFWS: ECDFG: E

Open water, sandyareas

PM

MammalsUrocyon littoralis dickeyi San Nicolas Island fox CDFG: T All terrestrial SNI

1 Sensitivity StatusU.S. Fish and Wildlife Service (USFWS)

E = EndangeredT= Threatened

California Department of Fish and Game (CDFG)T = Threatened R = RareE = Endangered

2 Habitat CodesCS = Coastal scrubCSM = Coastal salt marshCOD = Coastal dunes

3 Location CodesPM = Point MuguSNI = San Nicolas Island

4 Removed from USFWS endangered listing status on 25 August 1999.Source: NAWCWPNS Point Mugu 1998d.

3.8.1.2 Regional Setting

The Sea Range is a biologically important area encompassing California’s Channel Islands and coastalwaters; Mugu Lagoon is the largest relatively undisturbed coastal salt marsh along the southernCalifornia coastline. San Nicolas Island provides important breeding habitat for sensitive birds andmammals. Nearshore and open water areas of the Sea Range are used by resident and migratory seabirdsfor foraging and loafing. (Marine mammals are discussed in Section 3.7.)

Coastal salt marsh habitats in California have declined by over 90 percent of their original acreage(Zedler 1997). Mugu Lagoon is no exception; approximately 50 percent of its original acreage has beenlost to development, erosion, and sea level rise. Coastal wetlands provide a variety of functionsincluding sensitive species support, improvement of water quality, and flood flow reduction. Generally,

3.8-3

the larger the acreage of diverse healthy habitat, the more functions the wetland is capable of supportingand the more individuals it is capable of supporting; consequently, species diversity tends to increasewith size. Mugu Lagoon is home to seven sensitive species and provides a significant stop-over area inassociation with the Pacific Flyway, the migratory route used by many waterbird species.

Eight islands off the southern California coast comprise the Channel Islands. The four northern ChannelIslands—San Miguel, Santa Rosa, Santa Cruz, and Anacapa—form a chain that is the southern boundaryof the Santa Barbara Channel. The southern Channel Islands consist of San Nicolas, Santa Barbara,Santa Catalina, and San Clemente. Isolation from the mainland and a combination of geography, windpatterns, and ocean currents has created unique and diverse ecosystems. There are over 80 endemicspecies on the Channel Islands and over 60 of them are endangered or rare (California CoastalCommission 1987). San Nicolas Island is of moderate size (13,370 acres [5,410 ha]) when compared tothe other Channel Islands (ranging from 640 to 48,000 acres [260 to 19,400 ha]) and supports the fewestnumber of endemic and sensitive species. Following Santa Catalina, San Nicolas Island is the second-most developed of the Channel Islands.

3.8.1.3 Region of Influence

The region of influence (ROI) for the alternatives addressed in this EIS/OEIS includes the Point MuguSea Range, Point Mugu, and San Nicolas, San Miguel, Santa Rosa, and Santa Cruz islands.

3.8.2 Point Mugu Sea Range

Seabirds may be associated with the marine environment or with their terrestrial habitats. For purposesof this document, seabirds are discussed in the terrestrial resource section because the majority ofpotential impacts analyzed in Section 4.8 may occur when the seabirds are using terrestrial habitats.

Over 195 species of seabirds use open water, shore, or island habitats in the SCB (Baird 1990). Themajority of seabirds that are found in the SCB and the Sea Range are transitory, migrating in and out ofthe area according to breeding season. All seabirds that breed within the SCB, with the exception ofterns, do so on the Channel Islands (Baird 1990). Seabird species that are known to occur within the SeaRange are summarized in the Natural Resources Summary Report (NAWCWPNS Point Mugu 1999);seabird densities are shown in Figure 3.8-1. The greatest seabird species diversity occurs during the falland spring migration, and the least diversity occurs in June and July (Baird 1990). Seabird densitythroughout the Sea Range is low most of the time except for areas adjacent to the California coast and thecoastlines of the Channel Islands (see Figure 3.8-1).

Seabird density within the Sea Range was calculated using density data collected from May 1975 throughMarch 1978 (MMS 1993). Aerial and ship surveys were conducted along pre-established transectsdesigned to systematically sample seabird abundance in the SCB. Since a large scale, systematic seabirdsurvey has not been conducted subsequent to this effort, these data represent the best available for theROI. Density data from these surveys was put into a Geographic Information System (GIS) database, andseabird density per cell within the Sea Range was calculated. Seabird density ranges from 2.56 to 295.37birds per square mile (0.99 to 114.09 birds/km2), or less than 0.01 to 0.46 birds per acre (0.02 to 1.14birds/hectare) (Table 3.8-2).

Seabird Density in the Point Mugu Sea Range

W-412W-289N

M1

M37B

6B

W-537

M2

M1

6C5C

6D

7C

5B 4B

6A5A

4A

7A

W-61

W-60

W-290

3D

3A

3F 3E

8A5D

7D

M5

Vandenberg AFBSanta Barbara

VenturaPort Hueneme

NAS Point Mugu

LAX

LoBe

W13B/W2

Santa Barbara County

San Luis Obispo County

Santa Barbara County

Kern County

LACounty

VenturaCounty

W-532

W-289

SanMiguel

Santa Rosa

Santa CruzAnacapa

San Nicolas

San Clemente

Santa CatalinaSanta Barbara

3.8-1

N

EW

S

50 0 50 Nautical Miles

Figure

Projection: Universal Transverse MercatorNorth American Datum 1927

Zone 11Source: MMS 1993.

* Areas 5C, 6B, M2, 7A, W-537, and W-61 were partially surveyed.

Seabird Density0 - 50 Birds per Square Mile50 -100 Birds per Square Mile100 - 200 Birds per Square Mile200 + Birds per Square MileNo data available

3.8-5

Table 3.8-2. Average Seabird Density within the Sea Range

Range Area1Average Number of Birds

per Square Mile2Average Number of Birds

per Acre3A 63.09 0.093B/W2 196.71 0.313D 126.70 0.203E 52.47 0.083F 208.84 0.334A 295.37 0.464B 68.95 0.115A 2.93 <0.015B 17.02 0.035C3 3.47 <0.016A 2.56 <0.016B3 4.61 <0.01M23 2.59 <0.01M3 64.88 0.10M5 48.95 0.08W1 22.92 0.047A3 9.84 0.02W-5373 13.16 0.02W-289N 92.85 0.15W-412 122.22 0.19W-290 51.75 0.08W-60 6.19 <0.01W-613 6.45 <0.01C11773 55.35 0.091 Range areas are depicted on Figure 1-2.2 Based on MMS 1993 surveys.3 Partially surveyed.

3.8.3 Point Mugu

NAS Point Mugu lies within the SCB; with the exception of Mugu Lagoon, this location providesrelatively minor amounts of plant and wildlife habitat. Several habitats occur at Point Mugu (Figure3.8-2). Habitat designations are based on dominant plant species or physical features using a modifiedclassification from Zedler (1992). The most prominent combination of habitats at Point Mugu isassociated with Mugu Lagoon, an approximately 2,500-acre (1,010-ha) coastal salt marsh that providesfood, nesting, roosting, breeding, and nursery habitat for numerous benthic invertebrate, fish, bird, andplant species. Other habitats found at Point Mugu include beach and dunes, drainage ditch, transitiondisturbed, and developed areas.

Wildlife species may use a variety of habitats but are discussed under the vegetation community theytend to occupy the most. Mugu Lagoon and adjacent beach areas provide diverse and valuable habitatthat supports several threatened and endangered plant and wildlife species (discussed in the NaturalResources Summary Report [NAWCWPNS Point Mugu 1999]) and numerous common migratory andresident species.

Habitat Types at NAS Point Mugu

3.8-7

3.8.3.1 Coastal Salt Marsh

Coastal salt marsh is considered a sensitive and declining resource by several regulatory agenciesincluding the CDFG and USFWS. Wetlands are specifically addressed under the jurisdiction of the U.S.Army Corps of Engineers (USACE) section 404 permit process (§ 404, 33 U.S.C. § 1251 et seq.). CleanWater Act, as amended (33 U.S.C. § 1251 et seq.), permit provisions regulating dredge and fill operationsare enforced by the USACE and USEPA, with technical input from the USFWS.

Coastal salt marsh at Mugu Lagoon is defined by the presence of hydrophytic (salt-tolerant) vegetationand water levels that fluctuate daily due to tidal action. Salt marshes may appear to be monotypic;however, they often exhibit complex zonation based primarily on adaptation of plant and wildlife speciesto salinity fluctuations and hydrology. For purposes of mapping, the salt marsh at Mugu Lagoon isdivided into intertidal salt marsh and salt panne, intertidal mud flat and sand flat, open water and tidalcreeks, and non-tidal salt marsh. These habitat categories are discussed below.

A - Intertidal Salt Marsh and Salt Panne

These two habitat categories are discussed together because they often share similar plant and animalspecies. Intertidal salt marsh accounts for 783.9 acres (317.2 ha) of habitat; salt panne accounts for 210.6acres (85.2 ha) of habitat. Salt marsh habitat can be further divided into upper and lower marsh. Lowermarsh is dominated by pickleweed (Salicornia virginica) and is characterized by more frequent andlonger periods of tidal inundation than the upper marsh. Juncus sp. provides habitat for the federally andstate-endangered light-footed clapper rail (Rallus longirostrus levipes), which typically uses cordgrass(Spartina foliosa) for nesting habitat. The light-footed clapper rail is found in salt marshes dominated bytall, dense vegetation, which it uses for nesting and cover, and pickleweed, which it uses for foraging andhigh tide refuge (Figure 3.8-3). A 1995 population survey conducted throughout the clapper rail’sCalifornia range found 262 breeding pairs (Zembel et al. 1996). Of these, five pairs were found at MuguLagoon. There have been four to seven pairs present at the lagoon since 1985, and there is a male-biasedpool of singles: 12 and three single males in 1994 and 1995, respectively (Zembel et al. 1996). Surveysconducted in 1996 and 1997 found three pairs and three additional males (NAWS Point Mugu 1998d).

The upper marsh is a more diverse vegetation community than the lower marsh. Pickleweed is stilldominant, but other species are also present including sea lavender (Limonium californicum), alkali heath(Frankenia grandifolia), jaumea (Jaumea carnosa), saltwort (Batis maritima), arrowgrass (Triglochinconcinna), sea blite (Suaeda californica), and annual pickleweed (Salicornia bigelovii). Salt pannesoccur in upper marsh areas and are characterized by their lack of vegetation. Soils within salt panneshave a high salt content which inhibits the growth of salt marsh and upland plant species.

Belding’s savannah sparrow (Passerculus sandwichensis beldingi), listed by the State of California asendangered (CDFG 1997), is common throughout the salt marsh but prefers pickleweed-dominated areas(see Figure 3.8-3). Mugu Lagoon previously supported the largest population of Belding’s savannahsparrows in the state: 466 pairs were observed in 1986 (James and Stadtlander 1991). A partial surveyof the lagoon conducted in 1991 indicates that population levels have remained relatively stable (Jamesand Stadtlander 1991). A complete survey of Mugu Lagoon conducted in 1993 found 935 territorialmales (NAWS Point Mugu 1998d). Statewide censuses of breeding populations have been conducted inCalifornia. All potential breeding sites were surveyed in 1977, and 1,610 breeding pairs were estimatedto occur (NAWS Point Mugu 1998d). In 1986, 2,274 pairs were estimated to occur (NAWS Point Mugu1998d). The last statewide survey in 1991 found 1,844 pairs. Restricted access to the lagoon may beresponsible for the stable population at Mugu Lagoon.

MiddlePoint

LagunaPoint

Point MuguRock

LagunaPeak

VenturaCounty

MiddlePoint

LagunaPoint

Point MuguRock

LagunaPeak

VenturaCounty

MiddlePoint

LagunaPoint

Point MuguRock

LagunaPeak

VenturaCounty

MiddlePoint

LagunaPoint

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VenturaCounty

MiddlePoint

LagunaPoint

Point MuguRock

LagunaPeak

VenturaCounty

MiddlePoint

LagunaPoint

Point MuguRock

LagunaPeak

VenturaCounty

3.8-3Figure

Projection: Universal Transverse Mercator, Zone 11North American Datum of 1927

Source: Geographical Information System-NAWS Point Mugu 1997.

N

EW

SPeregrine Falcon Feeding AreasDesignated Snowy Plover Critical Habitat

Light-Footed Clapper Rail HabitatLegend

Sensitive Avian Species at NAS Point Mugu

3000 0 3000 Meters

Brown Pelican

Snowy Plover

Light-Footed Clapper Rail

Peregrine Falcon

Least TernBelding's

Savannah Sparrow

2 0 2 Statute Miles

Least Tern Breeding AreasBelding's Savannah Sparrow AreasBrown Pelican Roosting AreasBrown Pelican Feeding Areas

Least Tern Foraging Areas

3.8-9

The federally and state-listed endangered salt marsh bird’s-beak (Cordylanthus maritimus ssp.maritimus) is an annual plant, blooming from May to October. It is found primarily in coastal saltmarshes. This species is hemiparasitic, meaning it augments its nutrient supply by feeding on a hostplant or uses its host plant for mechanical support. Salt marsh bird’s-beak is considered sensitive atMugu Lagoon, where a fluctuating population has been observed annually in the upper portions of thewestern marsh (Figure 3.8-4) (Smith 1993). The primary population occurs west of Runway 03 andsmaller populations occur east of Runway 03.

B - Intertidal Mudflat and Sandflat

Intertidal mudflats and sandflats occur adjacent to areas of open water and are exposed during low tidesand inundated during high tides. Approximately 346.7 acres (140.3 ha) of intertidal mudflat and sandflatoccur within Mugu Lagoon. These areas usually support a high number of benthic and epibenthicinvertebrates and are frequently used by foraging shorebirds.

C - Open Water and Tidal Creeks

Although a large component of the salt marsh at Mugu Lagoon is not vegetated, it provides importantwildlife habitat. Based on topography and hydrology, open water habitats may be divided into subtidalchannels, ponds, tidal creeks, and permanent open water. Generally, subtidal channels always have someamount of water in them regardless of the tide and serve as connections between the tidal inlet and armsof the lagoon. Subtidal ponds are channels that have been scoured so that they now form ponds. Tidalcreeks (232 acres [94 ha]) are usually shallow, narrow channels that carry the flood (incoming) tide intovegetated areas of the marsh, and drain the marsh during the ebb (outgoing) tide.

Fish and aquatic invertebrate assemblages found in open water habitat are similar to those in coastal saltmarshes throughout southern California and serve as an important forage base for other wildlife species.A total of 39 fish species have previously been identified in the lagoon (Onuf 1987), and 24 species werefound during a fall survey in 1993 (Saiki 1994). The most common fish species are arrow goby(Clevelandia ios), topsmelt (Atherinops affinis), staghorn sculpin (Leptocottus armatus), and shinersurfperch (Cymatogaster aggregata) (Onuf 1987). Invertebrate species diversity and abundance withinMugu Lagoon is primarily influenced by substrate type and inundation. Crustaceans are common in theintertidal areas, while bivalves are common in the lower to middle tidal channels. Polychaetes arecommon throughout the tidal channels. A more detailed discussion of aquatic organisms occurring inMugu Lagoon is presented in Sections 3.5 and 3.6, Marine Biology and Fish and Sea Turtles,respectively.

D - Non-tidal Salt Marsh

Approximately 49.3 acres (20.0 ha) of non-tidal salt marsh occur within Mugu Lagoon. Non-tidal saltmarsh is characterized by the same vegetation species found in higher marsh habitats, but they are notexposed to tidal fluctuations. Non-tidal salt marsh receives water from rainfall and extremely high tides.Non-tidal salt marsh may be used as a refuge for salt marsh inhabitants during high tides and as foragingand resting areas by resident and migratory birds.

Brackish marsh habitats (46 acres [19 ha]) have reduced water salinity (between 0.5 and 30 parts perthousand) and are considered part of non-tidal salt marsh for the purposes of this document. Brackishmarshes typically occur as a transition area between freshwater and marine water resources, such as acreek flowing into an estuary or lagoon. Vegetation more commonly associated with freshwater marshhabitats, such as cattails (Typha sp.) and bulrushes (Scirpus sp.), is found in brackish marshes.

Salt Marsh Bird's-Beak Distribution at NAS Point Mugu

Salt Marsh Bird's Beak Distribution

Structures

Surface Water

NAS Point Mugu

Airfield

Roads

3.8-11

The federally and state-listed endangered California brown pelican (Pelecanus occidentalis ssp.californicusi) is a regular inhabitant of Mugu Lagoon (see Figure 3.8-3). A study conducted fromOctober 1991 to 1993 found pelicans roosting at Mugu Lagoon regularly, with abundance peaking fromJune to September (Jacques et al. 1996). Mugu Lagoon serves as an evening staging area for pelicansthat forage or roost elsewhere during the night. The majority of pelican activity and highest densityoccurs at the mouth of the lagoon, while the western portion of the lagoon is used by fewer than 10 birdsper day. Small numbers of pelicans also forage in the lagoon and in the adjacent nearshore waters(Jacques et al. 1996). Mugu Lagoon is the closest mainland roost to the major breeding colony and nightroost at Anacapa Island; it serves as a staging area for birds using the island (Jacques et al. 1996). MuguLagoon provides a relatively secure roost due to restricted public access.

California least terns (Sterna antillarum ssp. brownii) can be found foraging in shallow open water andbreeding in sandy areas adjacent to Mugu Lagoon (see Figure 3.8-3). For a more detailed description ofthis species see Section 3.8.3.3.

Numerous other wildlife species inhabit the salt marsh year-round; 351 species of birds have beenidentified at Mugu Lagoon, including 151 species of waterbirds. Species diversity and abundance variesseasonally with migration; while December through February traditionally support the highest number ofbirds within the SCB, Point Mugu experiences high bird densities during the spring migration. MuguLagoon also provides habitat for transient species such as the white-faced ibis, which is a common wintervisitor. The peregrine falcon (Falco peregrinus anatum) can be found throughout the year at PointMugu. Peregrines are primarily found near large bodies of water where they feed on waterbirds.Peregrine falcon populations declined before the 1970s due to pesticide contamination which causedeggshell thinning and reduced reproductive success (Johnsgard 1990). Recovery goals for peregrinefalcon in California have recently been achieved. Peregrines nest on western Anacapa Island and may beobserved foraging in undeveloped areas of NAS Point Mugu (see Figure 3.8-3).

Amphibians and reptiles are uncommon in the salt marsh but do occur in the adjacent upland areas.Mammals, such as coyote (Canis latrans), gray fox (Urocyon cinereoargenteus), mule deer (Odocoileushemionus), and striped skunk (Mephitis mephitis holzneri), inhabit the upland areas of Point Mugu andmay make frequent foraging trips into Mugu Lagoon. Mugu Lagoon also supports numerous terrestrialinvertebrates including spiders, wasps, and moths.

3.8.3.2 Beaches and Dunes

Beach and dune habitat is characterized by shifting sand within the intertidal zone. The intertidal zone isthe area between the highest high tide and the lowest low tide and can be divided into three areas (upper,middle, and lower) based on the frequency and duration of inundation. Organisms that live within thiszone have adapted to a continually changing environment and physical factors such as grain size, slope,and biological tolerances which influence species diversity, abundance, and distribution. Approximately290.3 acres (117.5 ha) of beach and dune habitat occur on NAS Point Mugu.

The federally and state-listed endangered California least tern can be found foraging in shallow openwater and breeding along the beach habitat adjacent to Mugu Lagoon (see Figure 3.8-3). California leastterns nest in two locations at Mugu Lagoon: the western and eastern arm of the Mugu Lagoon barrierbeach. For some sites, breeding takes place in two waves, with the second wave dominated by first-timebreeders and re-nesting older adults. California least tern populations have increased throughout theirrange to 4,009 pairs in the 1997 breeding season; at Mugu Lagoon, populations increased from 69 pairsin 1996 to 75 pairs in 1997 (NAWS Point Mugu 1998d).

3.8-12

The federally listed threatened western snowy plover (Charadius alexandrinus ssp. nivosusi) nests onsandy beaches and dried mudflats adjacent to Mugu Lagoon from the beginning of April to mid-September. This species has been extensively observed at Point Mugu during the breeding season (Smith1993). Overall, the breeding population of plovers has decreased at Point Mugu (NAWS Point Mugu1998d). In 1996, the eastern arm of Mugu Lagoon beach had an average adult population of about 25birds during the nesting season, and in 1997, there was an average adult population of less than nine birds(NAWS Point Mugu 1998d). Declines in the average adult population also occur for the Holiday Beachpopulation; less than 20 birds were observed in 1996, and less than 11 birds were observed in 1997(NAWS Point Mugu 1998d).

On December 7, 1999, the USFWS published a final rule designating 28 areas along the Pacific coast ofthe U.S. as critical habitat for the western snowy plover. Critical habitat is defined as: 1) the specificareas within the geographic area occupied by a species on which are found those physical or biologicalfeatures (a) essential to the conservation of the species and (b) that may require special managementconsideration or protection; and 2) specific areas outside the geographic area occupied by a species at thetime it is listed, upon determination that such areas are essential for the conservation of the species. Thecoast of Point Mugu includes designated western snowy plover critical habitat (see Figure 3.8-3).

3.8.3.3 Mixed Transition Disturbed and Urban/Industrial

Disturbed areas are lands on which the native vegetation has been significantly altered by construction orother land-clearing activities, and the species composition and site conditions are not characteristic ofdisturbed phases of natural plant associations within NAS Point Mugu. Such habitat typically occurs invacant lots, along roadsides, and in construction staging areas; it is usually dominated by nonnativeannual species and perennial broadleafed species. Disturbed habitat occurs throughout Point Mugu.Approximately 1,124.9 acres (455.3 ha) of mixed transition disturbed habitat occur on NAS Point Mugu.

Developed land supports no native vegetation and is dominated by man-made structures and exoticlandscaping. These areas usually include commercial and private buildings, industrial sites, and roads.Developed areas occur throughout NAS Point Mugu. Approximately 1,348.8 acres (545.9 ha) ofdeveloped habitat occur on NAS Point Mugu.

3.8.4 San Nicolas Island

San Nicolas Island lies approximately 65 miles (105 km) southwest of Point Mugu and covers 13,370acres (5,411 ha). Twelve vegetation communities have been identified on San Nicolas Island (Halversonet al. 1996) (Figure 3.8-5). This includes five scrub communities (caliche, isocoma, baccharis, lupinus,and coreopsis scrub) which comprise 7,349 acres (2,974 ha) of habitat. Freshwater aquatic vegetationcommunities include vernal pools and riparian habitats. Coastal and inland dunes are found along thecoastline of San Nicolas Island, and coastal marsh is found in three small areas. Annual iceplant, nativeand nonnative grasslands, and disturbed and developed habitats also occur. Barren areas which supportno vegetation comprise 3,468 acres (1,476 ha) of habitat.

San Nicolas Island provides breeding habitat for several seabirds, including California brown pelican,western gull (Larus occidentalis), Brandt’s cormorant (Phalacrocorax penicillatus), and blackoystercatcher (Haematopus bachmani). California brown pelican has not bred on San Nicolas Island, butNAS Point Mugu staff believe it may start in the near future (NAWS Point Mugu 1997e). Species ofspecial concern and species that breed or use the island as a rookery are summarized below. Vegetationcommunities and wildlife species are discussed together in this section to provide the reader with an

3.8-14

overall picture of existing conditions. Wildlife species may use a variety of habitats but are discussedunder the vegetation community they occupy the most.

3.8.4.1 Scrub Habitats

Five scrub habitats (caliche, isocoma, baccharis, lupinus, and coreopsis scrub) occur on San NicolasIsland and are its dominant land cover (see Figure 3.8-5). Caliche scrub occurs at the southern boundaryof the island’s mesa. Isocoma scrub is the most commonly found scrub on San Nicolas Island, with 67percent of the native species on the island occurring in this scrub community. Baccharis scrub is foundin scattered patches on the mesa, particularly in drainages or other locations that are protected from wind;this species may pond water. Lupinus scrub occurs in two small patches of less than 3 acres (1.2 ha) andis rare on San Nicolas Island; it occurs in sandy areas of coastal scrub and is dominated by silver lupine.Giant coreopsis scrub is found on north-facing slopes on the north side of the island and accounts for1,348 acres (546 ha).

The federally listed threatened island night lizard (Xantusia riversiana) may be found in any habitat onthe island that provides abundant cover. In prickly-pear (Opuntia sp.) habitats, the majority of lizards arefound in older stands of cactus where growth is thick and dead pads have accumulated on the ground,providing adequate refuge (USFWS 1984).

The state-listed threatened San Nicolas Island fox (Urocyon littoralis dickeyi) is an opportunistic feeder,with insects and fruits comprising the majority of its diet. Birds, eggs, grasses, and small mammalsconstitute a lesser portion of its diet (Collins and Laughrin 1979). This species may be found in any ofthe habitat types present on the islands.

Bird species commonly found on the mainland also occur in a variety of habitats on San Nicolas Island,including rock wren (Salpinctes obsoletus), European starling (Sturnus vulgaris), orange-crownedwarbler (Vermivora celata), house sparrow (Passer domesticus), western meadowlark (Sturnellaneglecta), and house finch (Carpodacus mexicanus).

San Nicolas Island supports the highest percentage (46 percent) of nonnative plant species of all thesouthern Channel Islands (Junak and Vanderwier 1990). Of the 18 native plant species found on one ormore of the Channel Islands, San Nicolas Island buckwheat (Eriogonum grande var. timorum) and leafymalacothrix (Malacothrix foliosa ssp. polycephla) are endemic only to San Nicolas Island (Junak andVanderwier 1990).

San Nicolas Island buckwheat is a perennial shrub, often growing 4 to 8 inches (10 to 20 cm) high andflowering from March through June. This is the only species of Eriogonum that occurs naturally on SanNicolas Island, but two additional species have been introduced (Junak et al. 1995). San Nicolas Islandbuckwheat occurs on open, south-facing slopes and on adjacent canyon walls between 100 and 500 feet(30 and 152 m) elevation on the mid-slope and lower-slope portions of the southern escarpment. It canalso be found on sandstone ridgetops and slopes and coastal flats (Figure 3.8-6).

Leafy malacothrix is also endemic to San Nicolas Island. This annual blooms in the spring and occurs incoastal scrub habitats.

Trask’s milkvetch (Astragalus traskiae), a state-listed rare species, is a perennial herb with spreadingbranches; it blooms from March through July. This species is widespread and abundant along theperimeter of the island, especially in dunes, sandy coastal flats, and open sandstone slopes (Junak et al.

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1995). Populations range in size from a few scattered individuals to dense stands with thousands ofplants (see Figure 3.8-6).

3.8.4.2 Vernal Pools

Several vernal pools totaling 0.8 acre (0.3 ha) occur on the western and northeastern portions of the mesa(Halverson et al. 1996). Vernal pools are rare meadow-like habitats that support a unique flora and faunawhich have adapted to ephemeral (lasting for a short time) aquatic conditions. These habitats aretypically inundated during and after winter rains, flourish with rapid plant and aquatic invertebrategrowth and reproduction in the spring, and become dry and dormant during the summer months. Thedominant plant species identified in San Nicolas Island vernal pools is pale spike-sedge (Eleocharismacrostachya).

3.8.4.3 Riparian Habitats

Deep drainages on the south side of the island are bare and eroded; those on the mesa top and on thenorth side of the island have areas of erosion as well as areas with plant communities. There arecurrently only small disturbed patches of riparian habitat on San Nicolas Island which comprise about201 acres (81 ha).

3.8.4.4 Beaches and Dunes

Beach habitat (234 acres [95 ha]) is similar to that defined in Section 3.8.3.3. Two types of dune habitat,coastal and inland, occur on San Nicolas Island (see Figure 3.8-5). Coastal dunes covering 138 acres(56 ha) are scattered along the perimeter of the island. Plant communities on active dunes are diverseand scattered, with no species dominating over large areas. Sticky sand verbena (Abronia maritima)occurs near the water and is the most abundant. Dune malacothrix (Malacothrix incana), silver lupine(Lupinus albifrons), beach sand-verbena (Abronia umbellata), beach bur (Ambrosia chamissonis),iceplant (Mesembryanthemum sp.), island morning glory (Calystegia macrostegia ssp. amplissima),beach-primrose (Camissonia cheiranthifolia), and silver lotus (Lotus argophyllus) also occur on thecoastal dunes. Inland dunes (782 acres [316 ha]) occur behind the coastal dunes and have more stablesandy substrates. Hottentot-fig (Carpobrotus edulis) and Trask’s milkvetch are the dominant species inthis community. Non-native weedy species also occur here.

Beach spectaclepod (Dithyrea maritima) is a perennial species, occurring in coastal dunes. It bloomsfrom March to May. The species has been observed on the western end of San Nicolas Island. Beachspectaclepod is considered sensitive because of its limited distribution on San Nicolas Island.

Western snowy plovers nest and forage on the beaches and in the intertidal zone of San Nicolas Island(Figure 3.8-7). Snowy plovers breed from March 1 to September 15. Two to three eggs are laid in ashallow depression scraped into the sand and incubated for 24 days, mostly by the male. The scrapeusually has small pieces of shell, vegetation, or driftwood associated with it. Young fledge and areindependent within 29 to 47 days (Ehrlich et al. 1988). Western snowy plovers forage primarily on thewet sand at the beach-surf interface, where they feed on small crustaceans, marine worms, insects, andamphipods. Snowy plovers are year-round residents on San Nicolas Island. A 1993 survey (Wehtje andBaron 1993) found a total of 78 nest initiations, of which 59 hatched and 33 successfully fledged for atotal of 53 chicks. Some of the beaches around San Nicolas Island have been designated by the USFWSas western snowy plover critical habitat.

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3.8.4.5 Coastal Marsh

Coastal marsh is found primarily in three small areas along the eastern end of San Nicolas Island,covering a total of 9 acres (4 ha). Pickleweed and alkali heath (Frankenia salina) are the dominantspecies. Additional species include small-flowered iceplant (Mesembryanthemum nodiflorum), saltgrass(Distichilis spicata), California saltbush (Atriplex californica), island morning glory, and sickle grass(Parapholis incurva).

3.8.4.6 Annual Iceplant

Crystalline iceplant is found in areas that have been disturbed; it also occurs in a small area on the westend of the island. Additional species found among iceplant include sand peppergrass (Lepidiumlasiocarpum), matscale (Atriplex watsonii), small-flowered iceplant, and sickle grass.

3.8.4.7 Grasslands

The grassland community is a mixture of native and non-native species covering 1,738 acres (703 ha).Grasslands occur on the mesas of San Nicolas Island primarily along the northern half of the island.Dominant grasses are slender wild oats, foxtail (Hordeum murinum), ripgut brome, and red brome.Dominant forbs, which are all nonnative species, include bur-clover (Medicago polymorpha), commonsow-thistle (Sonchus oleraceus), and filaree (Erodium spp.). Australian saltbush (Atriplex semibaccata),a herbaceous (i.e., not woody) perennial, is an important component of the nonnative grassland found onthe island. The native perennial purple needlegrass (Nassella pulchra) is found primarily in associationwith shrubs such as lupine (Lupinus spp.) and coreopsis (Coreopsis spp.).

The island horned lark (Eremophila alpestris insularis) is a common resident of grassland habitat on SanNicolas Island.

3.8.4.8 Rock Headlands, Cliffs, and Barren Areas

Rock headlands, cliffs, and barren areas are primarily non-vegetated areas that occur along the perimeterof the island. They consist of exposed rocks and may be sparsely vegetated where soil has been trappedin rock crevices.

Western gulls breed along the Pacific coast, nesting on the ground either in solitary pairs, small colonies,or in very large colonies involving thousands of birds (Carter et al. 1992). San Nicolas Island has a largebreeding colony which is considered sensitive to human disturbance (Smith 1993) (see Figure 3.8-7).The breeding western gull population is stable on the island.

Brandt’s cormorant is a common year-round resident of San Nicolas Island, nesting along the westernend (see Figure 3.8-7). Carter et al. (1992) estimated 5,089 breeding cormorants at San Nicolas Island.They are colonial nesters, breeding from March through August on open ground in rocky areas; nests arepacked close to each other and are perennial, with fresh material added every year. Cormorants feedchiefly on fish obtained by diving. When disturbed, cormorants leave their nests and western gullstypically destroy the eggs and chicks.

California brown pelican day-roosting areas are scattered along the coastline, particularly along theeastern end of San Nicolas Island (see Figure 3.8-7). Storm-petrels and black storm-petrels are notknown to nest on San Nicolas Island but do occur within the Channel Islands; therefore, they do forage

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adjacent to San Nicolas Island and may expand their nesting activities to the island in the future. Thesespecies are known to forage within the Sea Range.

3.8.4.9 Disturbed and Developed

Disturbed habitat is typified by non-native grasses and invasive weedy species. This habitat displays adistinct lack of any native vegetation, and shows signs of brushing, off-road vehicle use, ornamentalplanting, or other disturbance. Developed land supports no native vegetation and often contains man-made structures such as buildings or roads. Developed areas occur primarily on the eastern end of SanNicolas Island, covering 324 acres (131 ha). Mockingbirds (Mimus polyglottos) and house finches(Carpodacus mexicanus) are often found within the developed areas.

3.8.5 Other Channel Islands

Sea Range facilities are located on San Miguel, Santa Rosa, and Santa Cruz islands (refer to Section3.0.1.3). These sites are characterized as disturbed and developed habitat typified by a lack of nativevegetation. The sites offer limited habitat value for terrestrial wildlife species.

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