Arroyo Toad DRECP · DRAFT March 2012 AMPHIBIANS Arroyo Toad (Anaxyrus (Bufo) californicus) 6668 2 March 2012 Distribution General The arroyo toad is endemic to the coastal plains,

DRAFT March 2012

AMPHIBIANS Arroyo Toad (Anaxyrus (Bufo) californicus)

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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). Further, the North American toads in the genus Bufo are now assigned to the new genus Anaxyrus (Crother 2008), although many species accounts still refer to the genus 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.

Photo courtesy of Kailash Mozumder.

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Distribution

General

The 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 the 5-Year Review for the species, populations were reported to occur in the following counties: Monterey, San Luis Obispo, Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside, Orange, San Diego, and Imperial (USFWS 2009) (Figure SP-R1). Since publication of the 5-year Review, the U.S. Geological Survey (USGS) determined from unpublished data that the putative arroyo toad populations in Imperial County are not valid records and, as a result, Imperial County is no longer considered a part of the species’ distribution (Fisher, pers. comm. 2012). Arroyo toads 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). However, as noted above, the species is no longer considered to occur in Imperial County because the putative arroyo toad records, including those from San Felipe, Vallecitos, and Coyote creeks, as well as the Whitewater Canyon Basin in Riverside County, have been determined to be invalid (Fisher, pers. comm. 2012). 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. The Independent Science Advisors (ISA) Report indicated historical occurrences as far downstream as Afton Canyon (DRECP ISA 2010), but the USGS indicates that the furthest downstream historical occurrence of

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the arroyo toad in the Mojave River may be around Oro Grande (Fisher, pers. comm. 2012). The recovery plan for the arroyo toad (USFWS 1999) also shows historical occurrences extending downstream only about as far as Oro Grande, and the basis for the ISA (2010) assertion is unknown.

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 9 of the Desert Slope Recovery Unit (USFWS 1999). These populations are found in the Mojave River Basin on the very edge of the Plan Area, potentially as far downstream as Oro Grande (Fisher, pers. comm. 2012). 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). The USGS suggests that suitable habitat may still be present downstream of the Mojave Forks Dam and potentially all the way to Oro Grande, but these areas may not have been adequate surveyed in the recent past (Fisher, pers. comm. 2012). 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

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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 toads 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 toads typically forage, aestivate, and reproduce. Breeding sites are typically located adjacent to 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 Arroyo Toad 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

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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–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 toads burrow into the friable soils of upland terraces and are also known to seek temporary shelter under other debris or mammal burrows. Arroyo toads enter aestivation (a state of dormancy somewhat similar to hibernation to

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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

April

May

June

July

Aug

Sep

Oct

Nov

Dec

Breeding Aestivation ________________ Source: Ramirez 2003

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 (Mitrovich et al. 2011). 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 toads 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

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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 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). 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 are the PCEs 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,

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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

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

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(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 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 (Mitrovich et al. 2010; 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 at least 75% of their historical range in California (USFWS 2009). They now survive primarily as small, isolated populations, having been extirpated from much of their historical habitat (USFWS 2009). There are known populations on private land and other non-federal lands in the Mojave River Basin and on the desert side of the San Gabriel Mountains. Until recently, populations were thought to occur in San Felipe, Vallecitos, and Coyote creeks, and the Whitewater River Basin, but these occurrences have since been determined by the USGS to be invalid (Fisher, pers. comm. 2012). Therefore, the only known desert populations are along the desert side of the San Gabriel Mountains and within the Mojave River Basin, and these populations should be the focus of the DRECP (Fisher, pers. comm. 2012).

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

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due to extensive habitat loss that occurred from about 1920 to 1980 (USFWS 1999).

Within the Desert Recovery Unit, threats are moderate in intensity and come primarily from non-native species, recreational activities and development.

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 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, although USGS indicates that their status in the area may be uncertain due to a lack of adequate surveys (Fisher, pers. comm. 2012). 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

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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 (USFWS 1999) identified the need for the establishing three self-sustaining metapopulations or populations within the Desert Recovery Unit. This included 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). However, the USGS has determined that the Jacumba population is not valid (Fisher, pers. comm. 2012).

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 USFS has developed Land Management Plans that provide protection for arroyo toads. Specific guidelines from the Land Management Plans include the following: (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).

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Data Characterization

Recent data show that some toad occurrences in the desert previously thought to be arroyo toads are not valid, including putative occurrences from San Felipe, Vallecitos, and Coyote creeks (Fisher, pers. comm. 2012). The exclusion of these areas from the Plan Area leaves only the populations on the desert side of the San Gabriel Mountains and in the Mojave River Basin for consideration in the DRECP. The current arroyo toad critical habitat designation concluded that the area north of State Route 138 within the western portion of Subunit 22a does not contain the physical or biological features essential to the conservation of arroyo toads (i.e., the PCEs) and, therefore, does not meet the definition of critical habitat for the arroyo toad (76 FR 7245–7467). However, the USGS indicates that suitable arroyo toad habitat exists north of State Route 138 and that habitat should continue to Mojave Forks Dam (Fisher, pers. comm. 2012).

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 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 these plans, management and monitoring of arroyo toad should be guided by the species recovery plan (USFWS 1999). Specifically, the population on private and other non-federal lands in the Mojave River is essential for delisting the arroyo toad (USFWS 2009).

Predicted Species Distribution in Plan Area

Because the arroyo toad has such a restricted range in the Plan Area (i.e., the Mojave River Basin), an expert-based suitable habitat model was not developed. Based on a qualitative delineation of its range along the Mojave River, there are approximately 90,494 acres of suitable habitat for

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arroyo toad in the Plan Area. Appendix B includes a figure showing the arroyo toad’s estimated range in the Plan Area.

Appendix C provides a summary of the methods used to model DRECP Covered Species with Maxent. For the arroyo toad, 23 occurrence points were used to train the Maxent model and 7 occurrence points were used to test the model’s performance. Overall, the Maxent model has excellent statistical support. The occurrence points occur in a limited geographical area relative to the Plan Area, increasing the predictive power of the model. Based on a natural break in the distribution of the probability of occurrence that Maxent estimates, all 100-meter grid cells with greater than 0.180 probability of occurrence were defined as arroyo toad habitat.

The Maxent model predicts 14,972 acres of arroyo toad habitat, compared with 90,494 acres qualitatively delineated within the Mojave River based on its estimated range. The Maxent model predicts arroyo toad habitat in a localized area around known occurrences at the head of the Mojave River between the San Bernardino Mountains and Victorville. The qualitative delineation of habitat along the Mojave River occurs in the same area, but is not as dispersed as the Maxent model. The qualitative delineation also includes arroyo toad habitat along the extent of the Mojave River where there are no records of occurrence in the DRECP database (Dudek 2011).

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.

70 FR 19562–19633. Final Rule: “ETWP; Final Designation of Critical Habitat for the Arroyo Toad (Bufo californicus).” April 13, 2005.

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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 (California Department of Fish and Game). 2011. “Anaxyrus californicus.” Element Occurrence Query. California Natural Diversity Database (CNDDB). RareFind, Version 4.0 (Commercial Subscription). Sacramento, California: CDFG, Biogeographic Data Branch. Accessed December 2011. http://www.dfg.ca.gov/biogeodata/cnddb/mapsanddata.asp.

Crother, B.I.. 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.

Dudek. 2011. “Species Occurrences–Anaxyrus californicus.” DRECP Species Occurrence Database. Updated November 2011.

Fisher, R. 2012. Personal communication (email and profile review

comments) from R. Fisher (U.S. Geological Survey) to K. Mozumder (ICF). March 8, 2012.

Griffin, P.C., T.J. Case, and R.N. Fisher. 1999. Radio Telemetry Study of Bufo californicus, Arroyo Toad Movement Patterns and Habitat

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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.

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.

Mitrovich, M.J., T. Matsuda, K.H. Pease, R.N. Fisher. 2010. “Ants as a Measure of Effectiveness of Habitat Conservation Planning in Southern California.” Conservation Biology 24(5):1239-1248.

Mitrovich, M.J., E.A. Gallegos, L.M. Lyren, R.E. Lovich, and R.N. Fisher.

2011. “Habitat Use and Movement of the Endangered Arroyo Toad (Anaxyrus californicus) in Coastal Southern California.” Journal of Herpetology 45(3):319-328.

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

Management Practices. Proposal submitted to Rancho Las Flores Limited Partnership. Carlsbad, California: Cadre Environmental.

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.

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. Carlsbad, California: Cadre Environmental.

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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. Carlsbad, California: Cadre Environmental.

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. Carlsbad, California: Cadre Environmental.

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

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.

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.

USFWS (U.S. Fish and Wildlife Service). 1999. Arroyo Southwestern Toad (Bufo microscaphus californicus) Recovery Plan. Portland, Oregon: U.S. Fish and Wildlife Service. July 24, 1999.

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USFWS. 2009. Arroyo southwestern toad (Bufo californicus (=microscaphus)) 5-Year Review: Summary and Evaluation. Ventura, California: U.S. Fish and Wildlife Service. August 2009.

Zeiner, D.C., W. Laudenslayer, and K. Mayer. 1988. California’s Wildlife, Volume I: Amphibians and Reptiles. Sacramento, California: California Department of Fish and Game.

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

Desert Renewable Energy Conservation Plan (DRECP) Baseline Biology Report

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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

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Species Range in California

Documents

Arroyo Toad DRECP · DRAFT March 2012 AMPHIBIANS Arroyo Toad (Anaxyrus (Bufo) californicus) 6668 2 March 2012 Distribution General The arroyo toad is endemic to the coastal plains,