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DRAFT March 2, 2012

AMPHIBIANS Arroyo Toad (Anaxyrus (Bufo) californicus)

6668 1 March 2012

Arroyo Toad (Anaxyrus (Bufo)

californicus)

Legal Status

State: Species of Special

Concern

Federal: Endangered

Critical Habitat: Originally designated on February 7, 2001 (66 FR

9414–9474); first revised April 13, 2005 (70 FR 19562–19633); proposed

revision October 13, 2009 (74 FR 52612–52664); revised February 9,

2011 (76 FR 7245–7467)

Recovery Planning: Final recovery plan, July 1999 (USFWS 1999)

Notes: Recommended listing action from Endangered to Threatened, 5-

Year Review, August 2009 (USFWS 2009)

Taxonomy

The arroyo toad (Anaxyrus (Bufo) californicus) is a relatively small (5 to

8.1 centimeters), stocky, blunt-nosed toad with spotted greenish gray to

tan warty skin (Stebbins 2003). A detailed description of the species’

physical characteristics can be found in Stebbins (1954). Arroyo toad is

one of three members of the southwestern toad complex (Bufo

microscaphus) in the Bufonidae. At the time it was federally listed as

endangered in 1994 (59 FR 64859–64867, arroyo toad was considered a

subspecies of southwestern toad (B. m. californicus). Based on recent

genetic studies, arroyo toad is now considered a separate species (B.

californicus) (66 FR 9414–9474). Recent taxonomic work has divided the

North American “Bufo” into the new genus Anaxyrus (Crother 2008).

Many species accounts still refer to the species as Bufo. However, the

resource agencies (e.g., California Department of Fish and Game (CDFG)

and U.S. Fish and Wildlife Services (USFWS) have adopted the new

genus Anaxyrus.

PERMISSION

PENDING

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Distribution

General

Arroyo toad is endemic to the coastal plains, mountains, and desert slopes

of central and Southern California and northwestern Baja California from

near sea level to about 8,000 feet (2,400 meters). In California, these areas

include the following counties: Monterey, Santa Ynez, Santa Clara, San

Luis Obispo, Los Angeles, Imperial, Riverside, Orange, San Diego, and

San Bernardino (USFWS 2009) (Figure SP-R1). Within these areas,

arroyo toad are generally found in both perennial and intermittent rivers

and streams with shallow, sandy to gravelly pools adjacent to sand or fine

gravel terraces.

Distribution and Occurrences within the Plan Area

Historical

The Plan Area falls within the Desert Recovery Unit designated in the

Recovery Plan, which includes arroyo toad populations on the northern

and eastern slopes of the San Gabriel, San Bernardino, and Peninsular

Mountain ranges in Los Angeles, San Bernardino, Riverside, San Diego,

and Imperial Counties (USFWS 1999). Historically populations have been

described from Little Rock Creek, which flows north from the Angeles

National Forest east of Palmdale in the Antelope Valley (Figure SP-R1).

However, current known populations in Little Rock Creek are located

south of the Plan Area. In addition populations were known from the

headwaters of the Mojave River in the San Bernardino National Forest

down into the Mojave Basin, with reference to historic occurrences as far

downstream as Afton Canyon (DRECP ISA 2010).

Within Anza-Borrego State Park historic populations are known from the

upper reaches of Coyote Creek, San Felipe Creek, and Vallecitos Creek

(USFWS 2009).

Recent

Within the Plan Area, arroyo toads are known to occur on the desert slopes

of the San Bernardino Mountains. Populations of arroyo toad known

within or directly adjacent to the Plan Area include those within Subregion

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9 of the Desert Slope Recovery Unit (USFWS 1999). These populations

are found in the Mojave River basins on the very edge of the Plan Area.

There are 51 recent occurrences (i.e., since 1990) of arroyo toad recorded

in the CDFG (2011) and USFWS (2011) databases, Specific populations

in the Plan Area are known from Little Horsethief Creek, Mojave Forks

Dam, and Rancho Las Flores (USFWS 2009) (Figure SP-R1). Also,

arroyo toads are located in Little Rock Creek in the Angeles National

Forest south of the Plan Area boundary.

Natural History

Habitat Requirements

The arroyo toad evolved in an ecological system that is inherently

dynamic, with marked seasonal and annual fluctuations in rainfall and

flooding. Breeding habitat requirements are highly specialized, and are the

key factors when determining habitat suitability. Specifically, arroyo toad

requires shallow, slow-moving stream and riparian habitats that are

naturally disturbed on a regular basis, primarily by flooding (USFWS

2009). Streams and washes with sandy banks free of dense vegetation with

mature willow (Salix spp.) stands, cottonwoods (Populus spp.), western

sycamore (Platanus racemosa), riparian habitats of semi-arid areas, and

small cobble streambeds provide suitable habitat for arroyo toad. In order

for breeding populations to persist, the stream system must be large

enough for regular channel scouring events to occur, but not so large that

all sands and habitat structure are lost after floods (Sweet 1992). Factors

that influence habitat suitability include stream order, elevation, and

floodplain width (Sweet 1992). Stream orders range from one to six. The

smallest channels with no tributaries are called first order streams. The

confluence of two first order streams forms a second order stream, the

confluence of two second order streams forms a third order, and so on.

Fifth and sixth order streams are usually large rivers. Looking at stream

order, arroyo toad typically are found in the upper sections of third to sixth

order streams that lack the finer silt and clay sediments but that are not

dominated by larger cobble and coarse sands. Areas of sandy or friable

(readily crumbled) soils are the most important habitat for the species, and

these soils can be interspersed with gravel or cobble deposits (70 FR

19562–19633). It is in these areas that arroyo toad typically forage,

aestivate, and reproduce. Breeding sites are typically located adjacent to

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sandy terraces (59 FR 64589–64867); at or near the edge of shallow pools,

low-flow stream channels, and ox-bows; and along in-stream sand bars

with minimal current (0 to 2 kilometers (1.24 miles) per hour) and little or

no emergent vegetation. Upland non-breeding habitat used during

aestivation (described below) includes sage scrub, grassland, mixed

chaparral, oak woodland, and sagebrush.

Table 1. Habitat Associations for (Anaxyrus (Bufo) californicus)

Land Cover Type

Land Cover Use

Habitat Designation

Habitat Parameters

Supporting Information

Aquatic Breeding, larval/ juvenile development

Breeding All life stages occur around breeding

sites

Sweet 1992

Friable soils of upland terraces

Refugia Foraging, aestivation

Juvenile and adult

Foraging Requirements

Larvae (tadpoles) are highly specialized feeders on loose organic material

such as detritus, interstitial algae, bacteria, and diatoms (Sweet 1992).

Subadult and adult arroyo toads are opportunistic feeders, foraging on

immediately available prey located throughout both their breeding and

upland habitats. Adults feed on a variety of invertebrates, including snails,

Jerusalem crickets, beetles, ants, caterpillars, moths, and occasionally

newly metamorphosed individuals. They usually feed at night, but may

occasionally feed during the day (Zeiner et al. 1988). Juvenile toads,

which are mostly diurnal feeders for their first 4 to 5 weeks, primary

subsist on ants (Liometopum occidentale) around the saturated areas near

breeding pools (USFWS 1999). After this period of rapid growth, they

become more nocturnal and feed mostly on ants and beetles (Sweet 1992).

Reproduction

Arroyo toad breeding period occurs from late January or February to early

July, although it can be extended in some years depending on weather

conditions (USFWS 1999). Breeding in mountainous habitats

characteristic of the Plan Area populations may commence later (May–

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June) and last longer (to August) than in the coastal portion of the range.

Breeding occurs in quiet, clear backwaters of streams as waters recede

from the floods of the wet season. Adult males typically advertise at night

with a soft, high-whistled trill from suitable breeding habitat. Receptive

females seek out calling males based on the size of the male and the sound

of the call.

Although males may breed with several females in a season, females

release their entire clutch of eggs in a single breeding effort and probably

do not produce a second clutch during the season. Eggs are usually

deposited in tangled strings of 1 or 2 rows, on the bottom of shallow pools

with minimal current (0 to 2 kilometers (1.24 miles) per hour), little or no

emergent vegetation, and sand or pea gravel substrate. The eggs are

sensitive to siltation and require good water quality. Because the eggs are

laid in very shallow water and are not anchored or attached, rapid changes

in stream flow can wash them away or leave the eggs stranded to dry out.

Embryos usually hatch in 4 to 6 days; the larval period lasts approximately

65 to 85 days. The tadpoles reach a maximum length of about 1.5 inches

and are solitary and extremely cryptic, typically mottled or spotted with

blackish to brown colors.

After metamorphosis from June to August, the juveniles remain on the

bordering gravel bars until the pools no longer persist. Sexual maturity is

reached in 1 to 2 years. Outside of the breeding season, arroyo toad

burrow into the friable soils of upland terraces and are also known to seek

temporary shelter under other debris or mammal burrows. Arroyo toad

enter aestivation (a state of dormancy somewhat similar to hibernation to

prevent dehydration during hot or dry times of the year) in their burrows

during the non-breeding season, starting in the late summer from about

August and extending to about January (Ramirez 2003).

Table 2. Key Seasonal Periods for Arroyo Toad

Jan

Feb

Mar

ch

Ap

ril

May

Jun

e

July

Au

g

Sep

Oct

No

v

Dec

Breeding

Aestivation

________________

Source: Ramirez 2003

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Spatial Behavior

The extent of lateral arroyo toad movements away from the stream

channel is influenced by rainfall amounts, availability of surface water,

width of streamside terraces and floodplains, vegetative cover, and

topography (Griffin et al. 1999; Ramirez 2000). In broad, sandy

floodplains, arroyo toad often move across parallel stream channels in

search of suitable sites to lay eggs. In their study of arroyo toad movement

patterns, Griffin et al. (1999) observed female arroyo toad using riparian

and upland habitats an average maximum distance of 443 feet with a

maximum of more than 984 feet perpendicular to streams, while males

moved an average maximum distance of 240 feet from the streams. Within

stream movement was documented up to 492 feet. The study found that

both male and female arroyo toad moved more into upland habitats after

completing individual breeding activity. Female arroyo toad become more

sedentary as they mature, while males tend to move up and downstream

fairly often during the breeding season (Sweet 1993). Holland (USFWS

1999) found that arroyo toad are capable of moving 0.3 to 1.3 miles (0.5 to

2.0 kilometers) into suitable adjacent habitats and may not be constrained

by topography. In a study using pitfall traps, Holland and Sisk (2001)

captured arroyo toads in upland habitats averaging more than 980 and

1,640 feet from two coastal streams; one arroyo toad was captured 3,940

feet beyond the edge of the riparian habitat bordering the stream. Four

separate studies of inland populations by Ramirez (2002a, 2002b, 2002c,

2003) showed that arroyo toads burrowed no farther than 1,062 feet from

the edge of a stream, with an overall average of approximately 52 feet

between a burrow and the edge of the stream. The extent of movement

away from the stream channel is influenced by climatic conditions,

availability of surface water, floodplain width, vegetative cover, and

topography (Griffin et al. 1999, Ramirez 2002a). Moderate, stable

temperatures and high humidity facilitate longer-distance movements into

upland habitats (USFWS 1999). Juvenile arroyo toads disperse away from

their natal pools about 1 year after metamorphosis (Sweet 1993).

During the non-breeding season (August–January), arroyo toads usually

enter aestivation to prevent dehydration during the hot and dry periods of

the year. During rainfall events and moderate temperatures (above 7°C

(45°F)), they are known to be active during all times of the year. All age

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classes of post-metamorphic toads may be active on rainy nights and on

some nights of very high relative humidity (USFWS 1999).

Table 3. Movement Distances for Arroyo Toad

Type Distance Citation

Adult female upland dispersal

Average max 443 feet (max 984 feet)

Griffin 1999

Adult male upland dispersal

Average max 240 feet

Griffin 1999

Juvenile Dispersal

0.8–1km Sweet 1993

Upland aestivation

Average 52 feet from stream (max 1,062 feet)

Ramirez 2002a, 2002b, 2002c, 2003

Ecological Relationships

The arroyo toad is a breeding habitat specialist (Sweet 1992; Sweet and

Sullivan 2005). They require shallow pools located in open sand and

gravel channels, along low gradient (typically less than 6%) reaches of

medium-to-large-sized streams (Sweet 1992). Within the 2005 USFWS

critical habitat designation they identified the Primary Constituent

Elements (PCE) necessary for arroyo toad survival and reproduction. The

following represent PCE for arroyo toads (70 FR 19562–19633):

1. Rivers or streams with hydrologic regimes that supply water to provide

space, food, and cover needed to sustain eggs, tadpoles, metamorphosing

juveniles, and adult breeding toads. Specifically, the conditions necessary

to allow for successful reproduction of arroyo toads are:

a. Breeding pools with areas less than 12 inches (30 centimeters)

deep;

b. Areas of flowing water with current velocities less than 1.3 feet

per second (40 centimeters per second); and

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c. Surface water that lasts for a minimum length of 2 months in

most years (i.e., a sufficient wet period in the spring months to

allow arroyo toad larvae to hatch, mature, and metamorphose).

2. Low-gradient stream segments (typically less than 6% slope) with

sandy or fine gravel substrates that support the formation of shallow pools

and sparsely vegetated sand and gravel bars for breeding and rearing of

tadpoles and juveniles.

3. A natural flooding regime, or one sufficiently corresponding to a natural

regime that will periodically scour riparian vegetation, rework stream

channels and terraces, and redistribute sands and sediments, such that

breeding pools and terrace habitats with scattered vegetation are maintained.

4. Riparian and adjacent upland habitats (e.g., alluvial scrub, coastal sage

scrub, chaparral, and oak woodlands, but particularly alluvial streamside

terraces and adjacent valley bottomlands that include areas of loose soil

where toads can burrow underground) to provide foraging, aestivation,

and living areas for subadult and adult arroyo toads.

5. Stream channels and adjacent upland habitats allowing for migration

between foraging, burrowing, or aestivating sites, dispersal between

populations, and recolonization of areas that contain suitable habitat.

These aquatic, riparian, and upland habitat PCEs form the bases of our

critical habitat units. These features are essential to the conservation of the

arroyo toad. All lands identified as essential and designated as critical

habitat contain one or more of the PCEs for the arroyo toad.

Introduced plants and predators have had substantial impacts on existing

populations, and may have contributed to regional extinctions of arroyo

toad. Exotic plant species (e.g., tamarisk (Tamarix spp.), giant reed

(Arundo donax), iceplant (Carpobrotus spp.), and pampas grass

(Cortaderia spp.)) may degrade arroyo toad habitat by contributing to

altered hydrology, eliminating sandbars and breeding pools, and restricting

access to and quality of upland habitats (69 FR 23253–23328). Potential

non-native predators include bullfrog (Lithobates catesbeianus), African

clawed frog (Xenopus laevis), crayfish (Procambarus spp.), and green

sunfish (Lepomis cyanellus); increases in mesopredators (e.g., common

raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) often

associated with urban development can threaten or eliminate toad

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populations (69 FR 23253–23328, Jennings and Hayes 1994, USFWS

1999). Because native ants are a major food source for juveniles during

their rapid growth stage in the weeks following metamorphosis, the spread

of the non-native Argentine ant (Linepithema humile) into arroyo toad

habitat may displace native ants and other macroinvertebrates (Stephenson

and Calcarone 1999).

Population Status and Trends

Global: Declining to Stable (USFWS 2009)

State: Declining to Stable (USFWS 2009)

Within Plan Area: Declining (USFWS 2009)

Arroyo toads have disappeared from approximately 75% of their historic

range in California. They now survive primarily as small, isolated

populations, having been extirpated from much of their historic habitat

(USFWS 2009). There are two known populations on private land and

other non-Federal lands in the Mojave and Whitewater River Basins and

on the desert side of the San Gabriel Mountains. Historically populations

were found in San Felipe Creek, Vallecitos Creek and Coyote Creek

however these populations have not been confirmed recently. Within the

Desert Recovery Unit threats are moderate in intensity and come primarily

from recreational activities and development.

Threats and Environmental Stressors

Historically, because arroyo toad habitats are favored sites for dams and

reservoirs, roads, mining, agriculture, livestock grazing, urbanization, and

recreational facilities, such as campgrounds and off-highway vehicle

parks, many arroyo toad populations were reduced in size or extirpated

due to extensive habitat loss that occurred from about 1920 to 1980

(USFWS 1999). The specific threats to the known populations within the

Plan Area are described below.

Arroyo toad in Little Rock Creek are threatened by non-native species,

including crayfish, bullfrogs, non-native fishes, and recreational activities

such as hiking, fishing, boating, waterplay, and occasional off-highway

vehicle use (USFWS 1999). Portions of Little Rock Creek have been

closed by the Angeles National Forest to protect the arroyo toad (USFWS

2009). As a result of dam construction and operation at Little Rock

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Reservoir, arroyo toads appear to be restricted to a 3-mile (4.8-kilometer)

stretch of stream habitat above Little Rock Reservoir.

The Little Horsethief Creek population is threatened by bullfrogs, non-

native fishes, off-highway vehicles, camping, and fishing, and by gold

prospecting activities (USFWS 1999). Off-highway vehicle use in the

Mojave Forks area has been identified as a factor contributing to the near

extirpation of toads downstream from Rancho Las Flores. Roads in the

area, especially Highway 173 at the Horsethief Canyon crossing, pose a

danger to arroyo toad during movement between Rancho Las Flores and

upstream areas. In addition, arroyo toad breeding habitat has been severely

altered by beaver dams at the Rancho Las Flores site (Ramirez 1999). The

dams disrupt normal stream flow by impounding water and inundating

breeding habitat, while encouraging the growth of riparian vegetation and

favoring non-native species. The deep pools provide habitat for a number

of non-native species that are detrimental to the continued existence of the

arroyo toad (USFWS 2009).

Arroyo toads have been nearly eliminated between Victorville and the

Mojave Forks Dam. Arroyo toads were once common throughout portions

of the West Fork Mojave and the area now occupied by Silverwood Lake

(USFWS 1999). Construction of the lake removed habitat where many

arroyo toad were formerly observed and collected (USFWS 1999). Until

2003, arroyo toad had not been reported from the Cleghorn/Silverwood

Lake area since just after the lake was formed in 1972. Toads are still

expected to occasionally disperse upstream toward the reservoir; however,

the dam and reservoir pose an insurmountable barrier to further upstream

movement. Introductions of beaver (Castor canadensis) in the main Mojave

River have also eliminated shallow breeding areas (USFWS 1999).

Conservation and Management Activities

The Arroyo Toad Recovery Plan identifies the need for the establishment

of three self-sustaining metapopulations or populations within the Desert

Recovery Unit. This includes one population in the Angeles National

Forest (Little Rock Creek), one metapopulation in the San Bernardino

National Forest (Mojave River Basin, including West Fork of the Mojave

River; Little Horsethief Canyon; and Deep Creek) and one population on

Bureau of Land Management (BLM) land (Pinto Wash Basin, in the

Jacumba (In-Ko-Pah Mountains) Wilderness Study Area).

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The San Bernardino National Forest has acquired an additional 68 acre

(27.5 hectares) of arroyo toad habitat in Bautista Canyon (70 FR 19562–

19633). The U.S. Forest Service (USFS) sponsored a 3-year

radiotelemetry study in Little Rock Creek from 1999 to 2001 to

characterize habitat use and movement by arroyo toad in order to inform

management of the species in the area (Ramirez 2002a). For example,

trails supporting off-highway vehicle activity in 1999 that crossed Little

Rock Creek were subsequently closed, and pools in this area exhibited

successful recruitment in 2001 (Ramirez 2002a).

The U.S. Forest Service has developed Land Management Plans that

provide protection to arroyo toads. Specific guidelines from the Land

Management Plans include (1) Standards and guidelines with measures to

protect arroyo toad habitat that are incorporated into projects for managing

vegetation, soil, water, and riparian areas; (2) identification of the arroyo

toad as a Management Indicator Species to be used to track the health of

aquatic habitat; (3) specific requirements for monitoring and monitoring

activities that may affect arroyo toad habitat; (4) a five-step project

screening process to minimize impacts to riparian arroyo toad habitat; and

(5) guidelines for use of retardant and foams in aquatic environments to

minimize the impacts of these chemicals to the arroyo toad and its habitat

during fire suppression activities (USFWS 2009).

Data Characterization

Historically, populations were found in the San Felipe Creek and

Vallecitos Creek basins in what is now Anza-Borrego State Park. These

drainages, as well as Coyote Creek and other potential desert slope sites

should be surveyed and protected as appropriate (USFWS 2009). The

most recent critical habitat designation determined that the area north of

State Route 138 does not contain the physical or biological features

essential to the conservation of arroyo toads and, therefore, does not meet

the definition of critical habitat for the arroyo toad (76 FR 7245–7467).

Management and Monitoring Considerations

Within the Plan Area the USFS has developed long-term management

plans for the populations of arroyo toad within national forests. These

plans direct USFS staff to ensure that any project activities conducted in

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arroyo toad suitable habitat in the national forests are neutral or beneficial

to arroyo toads, and any expansion of existing facilities or development of

new facilities will focus recreational use away from arroyo toad occupied

habitat (USFWS 2009). Aside from those plans, management and

monitoring of arroyo toad should be guided by the species recovery plan.

Specifically, two known populations on private and other non-federal

lands in the Mojave River and Whitewater River Basins is essential for

delisting the arroyo toad (USFWS 2009).

Predicted Species Distribution in Plan Area

[TBD with species models.]

Model Summary

Primary Habitat—Nesting Habitat

[Describe primary habitat.]

Secondary Habitat—Foraging

[Describe secondary habitat.]

Model Results

[Summarize model results.]

Literature Cited

59 FR 64589–64867. Final rule: “Endangered and Threatened Wildlife

and Plants; Determination of Endangered Status for the Arroyo

Southwestern Toad.” December 16, 1994.

66 FR 9414–9474. Final rule: “Endangered and Threatened Wildlife and

Plants Final Designation of Critical Habitat for the Arroyo Toad.”

February 7, 2001.

69 FR 23253–23328. Proposed Rule: “Endangered and Threatened

Wildlife and Plants; Proposed Designation of Critical Habitat for

the Arroyo Toad (Bufo californicus).” April 28, 2004.

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70 FR 19562–19633. Final Rule: “ETWP; Final Designation of Critical

Habitat for the Arroyo Toad (Bufo californicus).” April 13, 2005.

74 FR 52612–52664. Proposed Rule: “Revised Critical Habitat for the

Arroyo Toad (Anaxyrus californicus).” October 13, 1009.

76 FR 7245–7467. Final Rule: “Revised Critical Habitat for the Arroyo

Toad.” February 9, 2011.

CDFG CNDDB DB 20111101. GIS data.

Crother, B.I. (Chair). 2008. Scientific and Standard English Names of

Amphibians and Reptiles of North America North of Mexico, with

Comments Regarding Confidence in Our Understanding. 6th

Edition. By the Committee on Standard English and Scientific

Names. Society for the Study of Amphibians and Reptiles

Herpetological Circular 37: iii + 86p.

DRECP ISA (Desert Renewable Energy Conservation Plan Independent

Science Advisors). 2010. “Recommendations of Independent

Science Advisors for the California Desert Renewable Energy

Conservation Plan (DRECP).” (DRECP-1000-2010-008-F)

October 2010. Prepared for Renewable Energy Action Team

(California Department of Fish and Game, U.S. Fish and Wildlife

Service, U.S. Bureau of Land Management, California Energy

Commission). Produced by Conservation Biology Institute.

Accessed March 3, 2011. http://www.drecp.org/

documents/index.html#science.

Griffin, P.C., T.J. Case, and R.N. Fisher. 1999. Radio Telemetry Study of

Bufo californicus, Arroyo Toad Movement Patterns and Habitat

Preferences. Contract Report to California Department of

Transportation Southern Biology Pool.

Holland, D.C., and N.R. Sisk. 2001. Habitat use and population

demographics of the arroyo toad (Bufo californicus) on MCB

Camp Pendleton, San Diego, California: final report for 1998-

2000. Prepared for AC/S Environmental Security, MCB Camp

Pendleton, Camp Pendleton, California. Fallbrook, California.

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Jennings, M.R., and M.P. Hayes. 1994. Amphibian and Reptile Species of

Special Concern in California. Prepared for the California

Department of Fish and Game, Inland Fisheries Division, Rancho

Cordova, California.

Ramirez, R.S., Jr. 1999. Rancho Las Flores Research Design and Best

Management Practices. Proposal submitted to Rancho Las Flores

Limited Partnership, by Cadre Environmental, Carlsbad,

California.

Ramirez, R.S., Jr. 2000. Arroyo Toad (Bufo californicus) Radio Telemetry

Study, Little Rock Creek; Los Angeles County, California.

Prepared for the USDA Forest Service, Angeles National Forest.

March 2000.

Ramirez, R.S., Jr. 2002a. Arroyo Toad (Bufo californicus) Radio

Telemetry Study, Little Rock Creek. Final Report. Prepared for

USDA Forest Service, Angeles National Forest. 62 pp.

Ramirez, R.S. 2002b. Arroyo toad (Bufo californicus) radio telemetry and

pitfall trapping studies, Little Horsethief Canyon, Summit Valley

Ranch, San Bernardino Co. Final Report to California Department

of Transportation. Cadre Environmental, Carlsbad, California.

Ramirez, R.S. 2002c. Arroyo toad (Bufo californicus) radio telemetry

study, San Juan Creek, Orange/Riverside Counties, California.

Interim Report 1 to the Cleveland National Forest. Cadre

Environmental, Carlsbad, California.

Ramirez, R.S., Jr. 2003. Arroyo toad (Bufo californicus) hydrogeomorphic

habitat baseline analysis/radio telemetry study – Rancho Las

Flores San Bernardino County, California. Final report to Rancho

Las Flores Limited Partnership by Cadre Environmental, Carlsbad,

California. vi + 101 pp.

Stebbins, R. C. 1954. Amphibians and Reptiles of Western North America.

New York: McGraw-Hill. p. 261.

Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians.

3rd ed. Boston, Massachusetts: Houghton Mifflin Company. 533 pp.

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Stephenson, J.R., and G.M. Calcarone. 1999. Southern California

Mountains and Foothills Assessment: Habitat and Species

Conservation Issues. Albany, California: Pacific Southwest

Research Station, Forest Service, U.S. Department of Agriculture.

General Technical Report GTR-PSW-172.

Sweet, S.S. 1992. Initial Report on the Ecology and Status of the Arroyo

Toad (Bufo microscaphus californicus) on the Los Padres National

Forest of Southern California, with Management

Recommendations. Report to U.S. Department of Agriculture,

Forest Service, Los Padres National Forest, Goleta, California. ii +

198 pp.

Sweet, S.S., and B.K. Sullivan. 2005. Bufo californicus Camp, 1915

ARROYO TOAD. In Amphibian Declines The Conservation

Status of United States Species. Ed. Michael Lannoo. University of

California Press, Ltd. London, Eng. pp. 396–400.

Sweet, S.S. 1993. Second Report on the Biology and Status of the Arroyo

Toad (Bufo microscaphus californicus) on the Los Padres National

Forest of Southern California. Contract report to U.S. Department

of Agriculture, Forest Service, Los Padres National Forest, Goleta,

California. ii + 73 pp.

USFWS. 1999. Arroyo Southwestern Toad (Bufo microscaphus

californicus) Recovery Plan. U.S. Fish and Wildlife Service,

Portland, Oregon. vi + 119 pp. July 24, 1999.

USFWS. 2009. Arroyo southwestern toad (Bufo californicus

(=microscaphus)) 5-Year Review: Summary and Evaluation. U.S.

Fish and Wildlife Service, Ventura, California. August 2009.

USFWS 2011. GIS database 20110125

Zeiner, D.C., W. Laudenslayer, and K. Mayer. 1988. California’s Wildlife,

Volume I: Amphibians and Reptiles. California Department of Fish

and Game, Sacramento, California. 272 pp.

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P a c i f i c

O c e a n

M E X I C OM E X I C O

A r i z o n aA r i z o n a

N e v a d aN e v a d a

U t a hU t a h

FIGURE SP-R1Arroyo Toad Occurrences in the Plan Area (N=51)

Desert Renewable Energy Conservation Plan (DRECP) Baseline Biology Report

0 2512.5MilesI

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Sources: DRECP Species Occurrence Database (2011), CWHR (2008), CEC (2010), USGS (2010), ESRI (2010)

Note: Occurrence point size graphically represents the precision level code for the data point but is not scaled geographically.

!( Current Occurrence Point

!( Historic Occurrence Point

Species Range in California

arroyo toad anaxyrus (bufo) californicus - drecp.org · draft march 2, 2012 amphibians arroyo toad...

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