3. Landuse designations and current or planned activities in the subject areas and their possible effects on proposed revised critical habitat;

4. Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas that exhibit these impacts;

5. Comments or information that may assist us in identifying or clarifying the primary constituent elements and the resulting physical and biological features essential to the conservation of the arroyo toad;

6. How the proposed revised critical habitat boundaries could be refined to more closely circumscribe the landscapes identified as essential;

7. Information regarding Trabuco Creek in Orange County and any special management considerations or protection that any essential physical or biological features in this area may require;

8. Information regarding the San Diego River in San Diego County from just below El Capitan Reservoir downstream to the confluence with San Vicente Creek, and any special management considerations or protection that any essential physical or biological features in this area may require;

9. Whether the potential exclusion under section 4(b)(2) of the Act of nonFederal lands covered by the Western Riverside County Multiple Species Habitat Conservation Plan from final revised critical habitat is or is not appropriate and why;

10. Whether the potential exclusion under section 4(b)(2) of the Act of nonFederal lands covered by the San Diego Multiple Species Conservation ProgramCity and County of San Diego's Subarea Plans from final revised critical habitat is or is not appropriate and why;

11. Whether the potential exclusion under section 4(b)(2) of the Act of nonFederal lands covered by the Coachella Valley Multiple Species Habitat Conservation Plan from final revised critical habitat is or is not appropriate and why;

12. Whether the potential exclusion under section 4(b)(2) of the Act of nonFederal lands covered by the Orange County CentralCoastal Subregional Habitat Conservation Plan/Natural Community Conservation Plan from final revised critical habitat is or is not appropriate and why;

13. Whether the potential exclusion under section 4(b)(2) of the Act of nonFederal lands covered by the Southern Orange County Natural Community Conservation Plan/Master Streambed Alteration Agreement/ Habitat Conservation Plan from final revised critical habitat is or is not appropriate and why;

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14. Whether the conservation needs of the arroyo toad can be achieved or not by limiting the designation of final revised critical habitat to nonTribal lands and why;

15. Whether the potential exclusion under section 4(b)(2) of the Act of Tribal lands of the Rincon Band of Luise[ntilde]o Mission Indians from final revised critical habitat is or is not appropriate and why;

16. Whether the potential exclusion under section 4(b)(2) of the Act of Tribal lands of the Pala Band of Luise[ntilde]o Mission Indians from final revised critical habitat is or is not appropriate and why;

17. Whether the potential exclusion under section 4(b)(2) of the Act of Tribal lands of the Sycuan Band of the Kumeyaay Nation from final revised critical habitat is or is not appropriate and why;

18. Whether the potential exclusion under section 4(b)(2) of the Act of Tribal lands of the Capitan Grande Band of Diegueno Mission Indians from final revised critical habitat is or is not appropriate and why;

19. Whether the potential exclusion under section 4(b)(2) of the Act of Tribal lands of the Mesa Grande Band of Diegueno Mission Indians from final revised critical habitat is or is not appropriate and why;

20. Whether our exemption under section 4(a)(3)(B) of the Act of the lands on Department of Defense land at Marine Corps Base, Camp Pendleton, in San Diego County; Fallbrook Naval Weapons Station in San Diego County; and Fort Hunter Liggett Military Reservation in San Luis Obispo County is or is not appropriate, and why;

21. Information on any quantifiable economic costs or benefits of the proposed revised designation of critical habitat;

22. Whether the benefit of exclusion of any other particular area not specifically identified above outweighs the benefit of inclusion under section 4(b)(2) of the Act;

23. Information on the currently predicted effects of climate change on the arroyo toad and its habitat;

24. Any foreseeable impacts on energy supplies, distribution, and use resulting from the proposed revised designation and, in particular, any impacts on electricity production, and the benefits of including or excluding any particular areas that exhibit these impacts; and

25. Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.

Our final determination concerning revised critical habitat for the arroyo toad will take into consideration all written comments received during the comment period, including comments requested from peer reviewers, comments received during a public hearing should one be requested, and any additional information we receive during the 60day comment period. Our final determination will also consider all written comments and any additional information we receive during the comment period for the draft economic analysis. All comments will be included in the public record for this rulemaking. On the basis of peer reviewer and public comments, we may, during the development of our final determination, find that areas within those proposed do not meet the definition of critical habitat, that some modifications to the described boundaries are appropriate, or that areas are or are not appropriate for exclusion under section 4(b)(2) of the Act.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section.

We will post your entire commentincluding your personal identifying informationon http://www.regulations.gov. If you provide personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy comments on http://www.regulations.gov. Please include sufficient information with your comment to allow us to verify any scientific or commercial data you submit.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

You may obtain copies of the proposed revised rule by mail from the Ventura Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT) or by visiting the Federal eRulemaking Portal at http:// www.regulations.gov.

Background

It is our intent to discuss only those topics directly relevant to the revised designation of critical habitat in this proposed rule. Additional information on the arroyo toad may also be found in the final listing rule published in the Federal Register on December 16, 1994 (59 FR 64859), the ``Recovery Plan for the Arroyo Southwestern Toad'' (recovery plan; Service 1999), and the designation of critical habitat for the arroyo toad published in the Federal Register on April 13, 2005 (70 FR 19562). These documents are available on the Ventura Fish and Wildlife Office and Carlsbad Fish and Wildlife Office Web sites at http://www.fws.gov/carlsbad. However, please note that this proposed rule incorporates new information on the distribution of arroyo toads that became available since the 2005 final critical habitat designation for this species. Taxonomy and Nomenclature

On December 16, 1994, we published a final rule listing the arroyo southwestern toad (Bufo microscaphus californicus) as endangered (59 FR 64859). This animal, originally described as Bufo cognatus californicus (Camp 1915, p. 331), has consistently been treated as a distinct taxon. However, its rank as a subspecies or species and taxonomic affiliations with other species has changed several times since it was described. Myers (1930, p. 75) elevated it to species rank as Bufo californicus citing morphological, vocalization, and ecological data to distinguish it from B. cognatus. Subsequent to Myers' paper, other authors again relegated the animal to subspecies rank aligned with various other species of Bufo. The name in use at the time of listing, Bufo microscaphus californicus, was published by Stebbins (1951, p. 275).

Since the toad was listed, an analysis of allozyme data (Gergus 1998, p. 322) supports recognition of Bufo californicus as separate from B. microscaphus. In addition, a phylogenetic analysis of comparative anatomical and molecular genetic data for amphibians (Frost et al. 2006, p. 363) segregated the Nearctic taxa of Bufo as the genus Anaxyrus and published the combination Anaxyrus californicus, the arroyo toad. This treatment is accepted by the Committee on Standard English and Scientific Names of the American Society of Ichthyologists and Herpetologists, The Herpetologists' League, and the Society for the Study of Amphibians and Reptiles (Frost et al. 2008, p. 3).

In light of these changes and their acceptance by the above scientific authorities, we are proposing to amend the List of Threatened and Endangered Wildlife at 50 CFR 17.11 to identify the [[Page 52614]]
listed entity as ``arroyo toad (Anaxyrus californicus).'' This change does not alter the description or distribution of the animals. Species Description

The arroyo toad is a small, darkspotted toad of the family Bufonidae. Its coloration ranges from light olive green or gray to light brown with a distinctive lightcolored, Vshaped stripe across the head and the eyelids. The belly is white or buff and often lacks dark blotches or spots (Stebbins 2003, p. 212). The species is endemic to the coastal plain and mountains of central and southern California, and northwestern Baja California, Mexico, from near sea level to about 8,000 feet (ft) (2,440 meters (m)) in elevation. For a detailed description of the species, see the recovery plan and references cited within the plan (Service 1999, pp. 1119), and information in previous Federal Register notices, proposed rules, and final rules (59 FR 64859, December 16, 1994; 66 FR 9414, February 7, 2001; 69 FR 23254, April 28, 2004; 70 FR 19562, April 13, 2005). In addition to the recovery plan, important sources for information on the biology of the arroyo toad include: Sweet (1992, pp. 1198; 1993, pp. 173); Campbell et al. (1996, pp. 146); Griffin et al. (1998, pp. 166); Griffin and Case (2001, pp. 633644); Holland and Sisk (2001); and Ramirez (2002a, pp. 162; 2002b; 2002c; 2003, pp. 1101).

Life History

Breeding typically occurs from February to July on streams with persistent water (Griffin et al. 1999, p. 1). Males may breed with several females in a season; however, female arroyo toads release their entire clutch of eggs as a single breeding effort and probably do not produce a second clutch during the mating season. Eggs are deposited and tadpoles develop in shallow pools with minimal current and little or no emergent vegetation. The substrate in these pools is generally sand or fine gravel overlain with silt. The eggs hatch in 4 to 5 days and the tadpoles are immobile for an additional 5 to 6 days. Tadpoles then begin to disperse from the pool margin into the surrounding shallow water, where they spend an average of 10 weeks. Peak metamorphosis occurs during June and July in the northern part of the arroyo toad's range, and from late April through June farther south, although it could occur later, particularly at higher elevations (Holland 2000, in litt. p. 8). After metamorphosis, the juvenile arroyo toads remain on the bordering gravel bars until the pool dries out (usually from 8 to 12 weeks depending on the site and rainfall). Most individuals become sexually mature by the following spring (Sweet 1992, p. 52).

Arroyo toad tadpoles feed on loose organic material such as interstitial algae, bacteria, and diatoms. They do not forage on macroscopic vegetation (Sweet 1992, p. 82; Jennings and Hayes 1994, p. 56). Juvenile arroyo toads feed on ants almost exclusively (Service 1999, p. 36). By the time they reach 0.7 to 0.9 inch (in) (1.78 centimeters (cm)) in length, they consume beetles along with ants (Sweet 1992, p. 99; Service 1999, p. 36). Adult arroyo toads probably consume a wide variety of insects and arthropods including (but not limited to) ants, beetles, spiders, larvae, and caterpillars. Geographic Range

The historical and current range of the arroyo toad extends from the Salinas River Basin southward through the Santa Ynez, Santa Clara, and Los Angeles River basins (Sweet 1992, p. 18), to Orange, Riverside, and San Diego Counties (Jennings and Hayes 1994, p. 54) and southward to the Arroyo San Simeon system, Baja California, Mexico (Service 1999, p. 12; Ramirez 2007, p. 5). Populations also occur on the desert slopes of both the San Gabriel Mountains (in Little Rock Creek in Los Angeles County) and the San Bernardino Mountains (in the Mojave River and in its tributaries, Little Horsethief and Deep Creeks, in San Bernardino County) (Sweet 1992, p. 18; Jennings and Hayes 1994, p. 54).

At the time of listing (59 FR 64859; December 16, 1994), arroyo toads were believed to be extirpated from the Salinas River Basin. In 1996, arroyo toads were found during surveys on the Fort Hunter Liggett Military Reservation approximately 40 miles (mi) (64 kilometers (km)) downstream of the historical Santa Margarita arroyo toad locality (U.S. Army Reserve 2004, pp. 510). In 1997, arroyo toads were detected along a 17mi (27km) stretch of the San Antonio River. The Army surveyed approximately 6 mi (9.6 km) of the San Antonio River on the Military Reservation in 2002 and estimated there were as many as 7,000 arroyo toad larvae (tadpoles) in the area (U.S. Army Reserve Command 2004, p. 12). We believe this population was present but undetected on Fort Hunter Liggett at the time of listing for the following reasons: (1) Annual surveys (U.S. Army Reserve 2004, p. 38) indicate there is suitable breeding and upland habitats for this large, robust population; and (2) given that the nearest extant population of arroyo toads is 150 mi (240 km) southeast of Fort Hunter Liggett in Santa Barbara County, it is unlikely that arroyo toads could have dispersed and newly colonized the Fort Hunter Liggett area by 1996, just 2 years subsequent to the species being listed in 1994. Therefore, we consider the population on Fort Hunter Liggett to have existed in 1994 and to represent the northernmost limit of the species' range at listing and currently. The geographical area occupied by the species at the time it was listed is the same as the species' current range in the coastal streams extending from Monterey County southward to San Diego County, and extending eastward into the riparian (along the shore of a river, stream, or lake) environments of San Bernardino and Riverside Counties.

Arroyo toads have been extirpated from approximately 75 percent of the habitat they originally occupied (Sweet 1992, p. 189; Jennings and Hayes 1994, p. 57; Campbell et al. 1996, p. 2). At present, arroyo toads are limited to isolated populations primarily in the headwaters of coastal streams. The species is likely restricted naturally as a result of specific habitat requirements for breeding and development (Service 1999, p. 39). These natural restrictions, coupled with the small sizes of many arroyo toad populations, make them particularly vulnerable to the negative effects of humaninduced changes to their habitat (Jennings and Hayes 1994, p. 57).

Habitat

Stream order, elevation, and floodplain width appear to be important factors in determining habitat suitability (Sweet 1992, pp. 2426; Griffin et al. 1999, pp. 13). Stream order ranks the size and potential power of streams. The smallest channels in a watershed with no tributaries are referred to as firstorder streams. When two first order streams unite, they form a secondorder stream; when two second order streams unite, they form a thirdorder stream, and so on. Fifth and sixthorder streams are usually larger rivers, while first and secondorder streams are often small, steep, or intermittent. In the northern portion of the range, arroyo toads are found on third to sixthorder streams (Sweet 1992, p. 24), while in the central and southern portion of the range, arroyo toads are found in first to sixthorder streams (Service 1999, p. 32).

Optimal breeding habitat consists of lowgradient sections of slow moving streams with shallow pools, nearby sandbars, and adjacent stream terraces. Arroyo toads breed and deposit egg masses in the shallow, sandy pools of these streams, which are usually
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bordered by sandgravel floodterraces. Breeding sites favored by adult arroyo toads have clear water in shallow (less than 12 in (30 cm) deep) pools (Sweet 1992, p. 28). Optimal breeding sites also have flow rates less than 1.97 in (5 cm) per second and bottoms composed of sand or wellsorted, fine gravel, although a significant component of large gravel or cobble may also be present (Sweet 1992, p. 37).

Stream terrace habitat consisting of alluvial bars and terraces that may have established cottonwoods (Populus spp.), oaks (Quercus spp.), or willows (Salix spp.) and almost no grass and herbaceous cover at ground level are extremely important for arroyo toads prior to, during, and after the breeding season (Griffin et al. 1999, p. 45; Sweet 1992, pp. 2849). Areas that are used by juveniles consist primarily of sand or fine gravel bars with varying amounts of large gravel or cobble and adjacent stable sandy terraces and oak flats. Juvenile arroyo toads favor areas that are damp and have some vegetation cover (less than 10 percent), which offer refugia and thermal characteristics that are needed for juvenile survival and rapid growth (Campbell et al. 1996, p. 12). Bare sand and gravel bars may support large numbers of juvenile toads, but survivorship can be reduced due to high levels of predation (Sweet 1992, p. 113).

Adult arroyo toads are often found on sandy alluvial terraces adjacent to the stream that may be sparselytoheavily vegetated with brush and trees, such as mulefat (Baccharis spp.), California sycamore (Platanus racemosa), cottonwoods, coast live oak (Quercus agrifolia), and willow (Campbell et al. 1996, pp. 1213). The understory of stream terraces may consist of scattered short grasses, herbs, and leaf litter, with patches of bare or disturbed soil, or have no vegetation at all. When foraging, juvenile and adult arroyo toads are often found around the drip lines of oak trees (Sweet 1992, pp. 4546; Campbell et al. 1996, p. 10). When active at night, arroyo toads can often be observed near ant trails feeding on passing ants and other prey.

Upland habitats used by arroyo toads during both the breeding and nonbreeding seasons include alluvial scrub, coastal sage scrub, chaparral (shrubby plants adapted to dry summers and moist winters), grassland, and oak woodland. Within terrace and upland habitats, arroyo toads aestivate (a state of dormancy similar to hibernation) in burrows during the nonbreeding season, which usually starts in the late summer and extends from August to January (Ramirez 2003, p. 46). In habitat utilization studies conducted by Ramirez (2007, pp. 1114) from 1999 to 2006 in the West Fork Mojave River and Grass Valley Creek areas, arroyo toads were generally found burrowed within sandy or loamy substrates with no associated canopy cover, or within mulefat scrub or arroyo willow (Salix lasiolepis) patches. The majority of individuals tracked in these studies burrowed immediately adjacent to the active channel or on sandy terraces within riparian habitat located within floodprone areas; however, toads were also found to use upland habitats up to 1,063 ft (324 m) from the active channel (Ramirez 2007, p. 13). In his 2005 study, Ramirez (2007, p. 93) observed several arroyo toad individuals burrowed in stable terrace habitats dominated by Great Basin sage scrub and Utah junipers (Juniperus osteosperma). At Little Rock Creek on the desert slopes of the San Gabriel Mountains, arroyo toads burrowed in areas closest to the creek that retained higher soil saturation and were cooler (Ramirez 2002a, p. 50). Griffin et al. (1999, p. 45) noted that sands are the preferred burrowing substrate for both male and female arroyo toads, confirming the importance of natural hydrologic regimes that maintain sand and fine sediment deposition across the floodplain.

Dispersal

Arroyo toad movement patterns also vary between watersheds or river reaches in response to different hydrological regimes (Griffin et al. 1999, p. 11). In broad floodplain river systems, arroyo toads searching for suitable egglaying sites may have to move across parallel stream channels. Cristianitos Creek, Talega Creek, and the lower San Mateo River are examples of this type of river system because of their wide, sandy floodplains where the river flows into several channels during floods. Despite river depths of 24 in (60 cm) and swift currents, Griffin et al. (1999, p. 21) observed numerous toads crossing Talega Creek and the lower San Mateo River, confirming these river systems are not a barrier to arroyo toad dispersal. In their study of arroyo toad movement patterns, Griffin et al. (1999, pp. 1821) tracked 10 female and 3 male arroyo toads in the lower San Mateo River and observed female arroyo toads regularly using riparian and upland habitats far from the river's edge and returning to these areas after traveling far upstream for egglaying. In one case, a female arroyo toad traveled 919 ft (280 m) across the San Mateo Campground into upland native habitat; in another instance, a female was found 558 ft (170 m) from the San Mateo River under cover of mulefat scrub (Griffin et al. 1999, p. 20). They also recorded arroyo toads moving in both up and downstream directions, such as the female arroyo toad that traveled upstream more than 492 ft (150 m) in a single night to a breeding pool. The study found that both male and female arroyo toads moved more into upland habitats after completing individual breeding activity (Griffin et al. 1999, p. 46).

In contrast, arroyo toads searching for breeding pools in watersheds with relatively narrower, steepersided drainages (such as the Piru and Sespe Creek Watersheds in Ventura County) tend to move in both up and downstream directions along these channels with their structure of alternating riffles and pools (Griffin et al. 1999, p. 11). In his Mono Creek study, Sweet (1993, pp. 2465), concluded that female arroyo toads became relatively sedentary as they matured whereas males tended to travel up and downstream fairly often during the breeding season (Sweet 1993, p. 65). This study also suggested that most juvenile arroyo toads disperse away from their natal pools about a year after metamorphosis (Sweet 1993, p. 65). In fact, numerous juvenile and adult arroyo toads were observed moving up and downstream as much as 0.5 mi (0.8 km) and over 0.6 mi (1 km) in some cases (Sweet 1993, p. 1). Arroyo toads in these watersheds also travel laterally away from the stream channel into terrace and upland native habitats. On lower Piru Creek, Sweet (1992, pp. 4245) observed two adult males under oaks that were 200 ft (61 m) away.

Reasons for Decline and Threats

A variety of factors contribute to the decline of arroyo toads but nearly half of historical extirpations prior to listing are attributed to dam building and operation (Sweet 1992, pp. 45; Ramirez 2003, p. 7). Suitable habitat is often flooded out by reservoir water, and downstream breeding and nonbreeding habitat may be severely altered by reduced flows at some times and sudden excessive flows at others. Sudden excessive releases of water may destroy sand bars used during the breeding season, and reconfigure or destroy suitable breeding pools, thus disrupting clutch and larval development (Ramirez 2003, p. 7). Additionally, dams can interrupt the scouring and deposition processes needed to maintain arroyo toad pool and terrace habitats. Areas below dams can become unsuitable as fine sands are lost and not replaced (Service 1999, pp. 4243).

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In addition to flood control projects, other threats include agriculture; sand and gravel mining; urban development; offhighway vehicle use; urbanization; recreational activities such as camping, fishing, hiking, picnicking; and natural factors, including drought and fire (59 FR 64859; Service 1999, p. 39; Ramirez 2003, p. 7). Conversion of stream terrace habitat for farming, road construction, and residential and commercial uses has eliminated substantial arroyo toad habitat in some areas. Suction dredge mining of sand and gravel causes substantial alteration of habitat by degrading water quality, altering stream morphology, increasing siltation downstream, and creating deep pools that hold water yearround for introduced predators of arroyo toad eggs and larvae (Campbell et al. 1996, p. 16). Natural disturbances, such as drought and fire, also threaten the arroyo toad (Campbell et al. 1996, p. 17). Prolonged drought can result in the loss of suitable breeding pools, foraging habitat, and prey availability (Sweet 1992, p. 190). Fire can affect arroyo toads by causing direct mortality and destruction of stream or terrace vegetation.

The introduction of nonnative species that compete for resources or that prey on arroyo toads also poses a serious threat to arroyo toad existence. The introduction of aquatic species not native to southern California watercourses has been facilitated by construction of the California Aqueduct and other sources of interbasin water transport (Service 1999, p. 48). Currently, the California Aqueduct is linked directly to the Santa Ynez River, Santa Clara River, San Jacinto River, and Mojave River Basins. Predatory species, many of which have used the aqueduct to colonize these river basins, include green sunfish (Lepomis cyanellus), largemouth bass (Micropterous salmoides), black bullhead (Ictalurus nebulosus), prickly sculpin (Cottus asper), stocked rainbow trout (Oncorhynchus mykiss), oriental gobies (Tridentiger spp.), red shiners (Notropis lutrensis), bullfrogs (Rana catesbeiana), African clawed frogs (Xenopus laevis), and crayfish (Procambarus clarkii) (Sweet 1992, pp. 118122; Service 1999, p. 48). All of these species prey on arroyo toad tadpoles.

Of the above introducedpredators, bullfrogs are probably the most serious threat to arroyo toads (Stephenson and Calcarone 1999, p. 82). Bullfrogs are well adapted to deep water conditions in ponded areas above dams, and dam releases can introduce them to downstream habitats (CDFG 2005, p. 178). A broad diet and an extended breeding season give bullfrogs a competitive advantage over native amphibians. Whereas arroyo toad breeding habitat requirements are highly specialized, in that they require shallow, slowmoving streams and riparian habitats that are disturbed on a regular basis, bullfrogs can tolerate elevated water temperatures and make use of standing pools resulting from urban runoff to complete their 2year life cycle (CDFG 2005, p. 178).

Introduced plants have also had a negative effect on arroyo toads and their habitat. Nonnative plant species, particularly tamarisk (Tamarix spp.) and giant reed (Arundo donax) alter the natural hydrology of stream drainages by eliminating sandbars, breeding pools, and upland habitats. Tamarisk is an aggressive, woody invasive plant species that can tolerate a variety of environmental conditions and has become established over as much as a million acres of floodplains, riparian areas, wetlands, and lake margins in the western United States (Carpenter 2004, pp. 130). Tamarisk can replace or displace native woody species such as cottonwood and willow which occupy similar habitats, especially when timing and amount of peak water discharge, salinity, temperature, and substrate texture have been altered by human activities (Carpenter 2004, pp. 130). Tamarisk also consumes large quantities of water, possibly more than woody native plant species occupying the same habitat (Carpenter 2004, p. 3). Highly resistant to removal by flooding, tamarisk has the potential to form dense corridors along most large streams. Where this has been allowed to occur, tamarisk has replaced native vegetation, invaded sand bars, and led to channelization by constricting flood flows. Arundo donax is a tall, grasslike plant that grows up to 20 ft (6.1 m) in height with jointed stems that resemble corn stalks. Arundo donax also invades stream banks and lakeshores, where it can completely displace native vegetation, reduce wildlife habitat, increase fire risks, and alter flow regimes which can cause flooding (Ventura County 2006, pp. 2123).

In summary, predation from introduced aquatic species and the loss of habitat, coupled with habitat modifications due to the establishment of nonnative plants and the manipulation of water levels in many central and southern California streams and rivers, have caused arroyo toads to disappear from a large portion of their previously occupied habitat in California.

Previous Federal Action

For more information on previous Federal actions concerning the arroyo toad, refer to our final designation of critical habitat published in the Federal Register on April 13, 2005 (70 FR 19562). On July 20, 2007 (Service 2007, pp. 12), we announced that we would review the April 13, 2005, final rule after questions were raised about the integrity of scientific information used and whether the decision made was consistent with the appropriate legal standards. Based on our review of the previous final critical habitat designation, we determined it was necessary to revise critical habitat and this rule proposes those revisions. On December 19, 2007, the Center for Biological Diversity filed a complaint in the U.S. District Court for the Southern District of California challenging our designation of critical habitat for the arroyo toad (Center for Biological Diversity v. U.S. Fish and Wildlife Service, Case No. 072380JMAJB). On June 5, 2008, the court entered a consent decree requiring a proposed revised critical habitat rule to be submitted to the Federal Register by October 1, 2009, and a final revised critical habitat designation to be submitted to the Federal Register by October 1, 2010.

Critical Habitat

Critical habitat is defined in section 3 of the Act as: (1) The specific areas within the geographical area occupied by a species, at the time it is listed in accordance with the Act, on which are found those physical or biological features;
(a) Essential to the conservation of the species; and
(b) That may require special management considerations or protection; and
(2) Specific areas outside the geographical area occupied by a species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.

Conservation, as defined under section 3 of the Act, means the use of all methods and procedures that are necessary to bring any endangered species or threatened species to the point at which the measures provided under the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping and transplantation, and in the extraordinary case where population
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pressures within a given ecosystem cannot otherwise be relieved, may include regulated taking.

Critical habitat receives protection under section 7 of the Act through the prohibition against Federal agencies carrying out, funding, or authorizing activities that are likely to result in the destruction or adverse modification of critical habitat. Section 7(a)(2) of the Act requires consultation on Federal actions that may affect critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by private landowners. Where a landowner seeks or requests Federal agency funding or authorization of an activity that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) would apply, but even in the event of a destruction or adverse modification finding, the Federal action agency's and the applicant's obligation is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.

To be considered for inclusion in a critical habitat designation, habitat within the geographical area occupied by the species at the time it was listed must contain the physical or biological features that are essential to the conservation of the species. Areas supporting the essential physical or biological features are identified, to the extent known using the best scientific data available, as the habitat areas that provide essential life cycle needs of the species; that is, areas on which are found the primary constituent elements laid out in the appropriate quantity and spatial arrangement essential to the conservation of the species. Habitat within the geographical area occupied by the species at the time of listing that contains features essential to the conservation of the species meets the definition of critical habitat only if these features may require special management considerations or protection. Under the Act and the regulations at 50 CFR 424.12, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed only when we determine that the best available scientific data demonstrate that the designation of those areas is essential for the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific and commercial data available. Further, our Policy on Information Standards Under the Endangered Species Act (published in the Federal Register on July 1, 1994 (59 FR 34271)), the Information Quality Act (section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106554; H.R. 5658)), and our associated Information Quality Guidelines, provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas to propose as revised critical habitat, our primary source of information is generally the information developed during the listing process for the species and any previous designations of critical habitat. Additional information sources may include the recovery plan and 5year reviews for the species, articles in peerreviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials and expert opinion or personal knowledge.

Habitat is dynamic, and species may move from one area to another over time. In particular, we recognize that climate change may cause changes in the arrangement of occupied habitat patches. Current climate change predictions for terrestrial areas in the Northern Hemisphere indicate warmer air temperatures, more intense precipitation events, and increased summer continental drying (Field et al. 1999, pp. 13; Hayhoe et al. 2004, p. 12422; Cayan et al. 2005, p. 6;
Intergovernmental Panel on Climate Change 2007, p. 11; Cayan et al. 2009, p. xi). However, predictions of climatic conditions for smaller subregions such as California remain uncertain. It is unknown at this time if climate change in California will result in a warmer trend with localized drying, higher precipitation events, or other effects. Thus, the information currently available on the effects of global climate change and increasing temperatures does not make sufficiently precise estimates of the location and magnitude of the effects. Nor are we currently aware of any climate change information specific to the habitat of the arroyo toad that would indicate what areas may become important to the species in the future. Therefore, we are unable to determine what additional areas, if any, may be appropriate to include in the proposed revised critical habitat for this species; however, we specifically request information from the public on the currently predicted effects of climate change on the arroyo toad and its habitat. Additionally, we recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated critical habitat area is unimportant or may not be required for recovery of the species.

Areas that support populations of the arroyo toad, but are outside the critical habitat designation, may continue to be subject to conservation actions we and other Federal agencies implement under section 7(a)(1) of the Act. They are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available information at the time of the agency action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, habitat conservation plans (HCPs), section 7 consultations, or other species conservation planning efforts if new information available to these planning efforts calls for a different outcome.

Methods

As required by section 4(b) of the Act, we used the best scientific and commercial data available in determining which areas within the geographic area occupied by the species at the time of listing contain the features essential to the conservation of the arroyo toad, and which areas outside the geographical area occupied at the time of listing are essential for the conservation of the species. We reviewed information used to prepare the 2004 proposed critical habitat rule (69 FR 23254); the approach to provide conservation for the arroyo toad provided in its recovery plan (Service 1999, pp. 1119); the 5year review for the arroyo toad (Service 2009, pp. 151); the California Department of Fish and Game's (CDFG) California Natural Diversity Database (CNDDB) records; published peerreviewed articles;
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unpublished papers and reports; academic theses; survey results; Geographic Information System (GIS) data (such as species occurrences, soil data, land use, topography, and ownership maps); and
correspondence to the Service from recognized experts. We solicited new information collected since publication of the recovery plan and 2005 final critical habitat designation, including information from State, Federal, and Tribal governments, and from academia and private organizations that have collected scientific data on the arroyo toad. We also based our determination of areas meeting the definition of critical habitat for the arroyo toad in part on the approach in the recovery plan that focuses on protection and management of breeding and nonbreeding habitat on a watershed basis for the conservation of the species (Service 1999, pp. 1119).

Physical and Biological Features

In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12(b), in determining which areas within the geographical area occupied at the time of listing to propose as revised critical habitat, we consider the physical and biological features that are essential to the conservation of the species that may require special management considerations or protection. Those features are the primary constituent elements (PCEs) laid out in the appropriate quantity and spatial arrangement for conservation of the species. The PCEs include, but are not limited to:
(1) Space for individual and population growth, and for normal behavior;
(2) Food, water, air, light, minerals, or other nutritional or physiological requirements;
(3) Cover or shelter;
(4) Sites for breeding, reproduction, and rearing (or development) of offspring; and
(5) Habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of a species.

We derive the specific PCEs required for conservation of the arroyo toad from its biological needs. The areas proposed for designation as revised critical habitat provide aquatic habitat for breeding activities and upland habitat for shelter, foraging, predator avoidance, and dispersal across the arroyo toad's current range. The PCEs and the resulting physical and biological features essential to the conservation of the species are determined based on studies of arroyo toad ecology as described in the ``Background'' section of this proposed rule and in the final listing rule published in the Federal Register on December 16, 1994 (59 FR 64859).
Space for Individual and Population Growth, and for Normal Behavior

The arroyo toad is found along mediumtolarge streams in coastal and desert drainages in central and southern California, and Baja California, Mexico. It occupies aquatic, riparian, and upland habitats in a number of the remaining suitable drainages within its range. Suitable habitat for the arroyo toad is created and maintained by the fluctuating hydrological, geological, and ecological processes that naturally occur in riparian ecosystems and adjacent uplands (Campbell et al. 1996, pp. 1315; Service 1999, p. 39). Periodic flooding that modifies stream channels, redistributes channel sediments, and alters pool location and form, coupled with upper terrace stabilization by vegetation, is required to keep a stream segment suitable for all life stages of the arroyo toad (Campbell et al. 1996, p. 13; Service 1999, p. 39). This natural flooding regime helps maintain areas of open, sparsely vegetated, sandy stream channels and terraces.

The substrate in habitats preferred by arroyo toads consists primarily of sand, fine gravel, or pliable soil, with varying amounts of large gravel, cobble, and boulders. Areas that are damp and have less than 10 percent vegetation cover provide the best conditions for juvenile survival and rapid growth (Campbell et al. 1996, p. 12; Service 1999, pp. 3234). Arroyo toads breed in the quiet margins of open streams and avoid sites with deep or swift water, tree canopy cover, or steeply incised banks. Larvae occupy shallow areas of open streambeds on substrates ranging from silt to cobble, with preferences for sand or gravel. Newly metamorphosed arroyo toads and juveniles remain on sparsely vegetated sand and gravel bars bordering the natal pool for 3 to 5 weeks (Sweet 1992, p. 52).

Arroyo toads must be able to move between the stream and upland foraging sites, as well as up and down the stream corridor. Juveniles and adult arroyo toads require and spend much of their lives in riparian and upland habitats adjacent to breeding locations (Campbell et al. 1996, p. 12). Riparian habitats used for foraging and burrowing include sand bars, alluvial terraces, and streamside benches that lack vegetation, or are sparsely to moderately vegetated. Upland habitats used by arroyo toads during both the breeding and nonbreeding seasons include alluvial scrub, coastal sage scrub, chaparral, grassland, and oak woodland.

Food, Water, and Physiological Requirements

Arroyo toad tadpoles eat microscopic algae, bacteria, and protozoans consumed from the spaces among pebbles, gravel, and sand, or abraded from stones (Sweet 1992, p. 82). Juveniles and adults eat insects, although ants are preferred. When foraging, arroyo toads are often found around the drip lines of oak trees. These areas often lack vegetation, yet have levels of prey that will support arroyo toads. When active at night, toads often are observed near ant trails feeding on ants, beetles, and other prey.

Cover or Shelter

During the day and other periods of inactivity, arroyo toads seek shelter by burrowing into sand. Thus, areas of sandy or friable (readily crumbled) soils are necessary, but these soils can be interspersed with gravel or cobble deposits. Additionally, arroyo toads may seek temporary shelter under rocks or debris and have been found in mammal burrows on occasion. Upland sites with compact soils can also be used for foraging and dispersal (Holland 2000, in litt.).

Sites for Breeding, Reproduction, and Rearing of Offspring

The arroyo toad has specialized breeding habitat requirements. They favor shallow pools (less than 12 in (30 cm) deep) and open sand and gravel channels along lowgradient (typically less than 6 percent) reaches of medium to large streams (Service 1999, pp. 3132). These streams can have either intermittent or perennial streamflow and typically experience periodic flooding that scours vegetation and replenishes fine sediments. In at least some portions of its range, the species also breeds in smaller streams and canyons where lowgradient breeding sites are more sporadically distributed. Breeding pools must persist long enough for the completion of larval development, which is generally March through June, depending on location and weather. Because the suitability of breeding pools may vary from year to year due to the dynamics of southern California riparian systems and flood regimes, adult arroyo toads may move up or down stream in search of suitable breeding pools, or not breed that year (Campbell et al. 1996, p. 14).

Arroyo toads breed in rivers with intermittent, seasonal flow, with a breeding period that may range from late February through July. Breeding at
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a given site may extend over several months (Griffin and Case 2001, p. 634). Breeding arroyo toads lay their eggs in water over substrates of sand, gravel, or cobble in open sites such as overflow pools, old flood channels, and shallow pools along streams. Such habitats rarely have closed canopies over the lower banks of the stream channel due to periodic flood events. Heavily shaded pools are generally unsuitable for larval and juvenile arroyo toads because of lower water and soil temperatures and poor algal mat development. Pools less than 12 in (30 cm) deep with clear water, flow rates less than 0.2 ft per second (5 cm per second), and bottoms composed of sand or wellsorted fine gravel are favored by adults for breeding and egg deposition (Sweet 1992, pp. 2937). Although egg strings are laid in very slowmoving water, larvae (tadpoles) can be found in water velocities of up to 1.0 to 1.3 ft per second (30 to 40 cm per second) (Sweet 1992, p. 29). Breeding may occur on several dates at a single site, and eggs may be deposited over a period of 7 to 8 weeks (Campbell et al. 1996, p. 6). Breeding pools must persist a minimum of 2 months for the completion of larval development because changes in stream level or altering of the stream bed or breeding pool may cause high mortality to eggs and small larvae, sweeping them downstream, stranding and exposing them to desiccation, or burying and asphyxiating them with silt (Campbell et al. 1996, p. 6). Larvae usually hatch in 4 to 6 days at water temperatures of 54 to 59 degrees Fahrenheit (12 to 16 degrees Celsius). Tadpoles disperse from the pool margin into the surrounding shallow water, where they spend an average of 10 weeks. After metamorphosis, the juvenile arroyo toads remain on the bordering gravel bars until the pool dries out (usually from 8 to 12 weeks depending on the site and rainfall). Primary Constituent Elements (PCEs) for the Arroyo Toad

Pursuant to the Act and its implementing regulations, when considering the designation of critical habitat, we must focus on the known principal primary constituent elements within the geographical area occupied by the arroyo toad at the time of listing that are essential to the conservation of the species. The essential physical and biological features are those PCEs laid out in an appropriate quantity and spatial arrangement determined to be essential to the conservation of the species. All areas proposed in this rule as revised critical habitat for the arroyo toad are currently occupied, are within the geographical area occupied by the species at the time of listing, and contain sufficient PCEs to support at least one lifehistory function.

Based on the above needs and our current knowledge of the life history, biology, and ecology of the species, and the habitat requirements for sustaining the essential lifehistory functions of the species, we have determined that the PCEs specific to the arroyo toad are:
(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. Breeding pools must persist a minimum of 2 months for the completion of larval development. However, due to the dynamic nature of southern California riparian systems and flood regimes, the location of suitable breeding pools may vary from year to year. Specifically, the conditions necessary to allow for successful reproduction of arroyo toads are:

In summary, the need for space for individual and population growth and normal behavior is met by PCE (1); the need for food, water and physiological requirements is met by PCE (1); cover and shelter requirements are met by PCE (2); areas for breeding reproduction, and rearing of offspring are met by PCEs (1), (2), and (3); and habitats representative of the historical, geographical, and ecological distributions of a species are met by PCE (4).

With this proposed revised designation of critical habitat, we intend to conserve the physical and biological features that are essential to the conservation of the species, through the
identification of the appropriate quantity and spatial arrangement of the PCEs sufficient to support the lifehistory functions of the species. Because not all lifehistory functions require all the PCEs, not all areas designated as critical habitat will contain all the PCEs. Each of the areas proposed for designation in this rule has been determined to contain sufficient PCEs to provide for one or more of the lifehistory functions of the arroyo toad.

Special Management Considerations or Protection

In accordance with the definition of critical habitat in section 3(5)(A) of the Act, when designating critical habitat within the geographical area occupied by the species at the time of listing, we assess whether the physical and biological features essential to the conservation of the arroyo toad may require special management considerations or protection. All areas being proposed as critical habitat may require some level of management to address current and future threats to the arroyo toad, to maintain or enhance the physical and biological features essential to its conservation, and to ensure the recovery and survival of the species.

A detailed discussion of threats impacting the physical and biological features essential to the conservation of the arroyo toad which may require special management considerations or protection, can be found in the final listing rule (59 FR 64859; December 16, 1994), the 2001 critical habitat designation (66 FR 9414; February 7, 2001), the 2005 critical habitat designation (70 FR 19561; April 13, 2005), and the recovery plan (Service 1999, pp. 1119). In summary, these threats include habitat destruction and alteration due to short and longterm changes in river hydrology, including
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construction of dams and water diversions; alteration of riparian wetland habitats by agriculture and urbanization; construction of roads; sitespecific damage by offhighway vehicle use and other recreational activities; overgrazing; and mining activities. Arroyo toads and their habitats are also threatened by introduced nonnative predators (such as bullfrogs and predatory fish), drought, periodic fires, unseasonal water releases from dams, livestock grazing, and light and noise pollution from adjacent developments and campgrounds. Activities that may require special management considerations or protection of the features essential to the conservation of the arroyo toad include, but are not limited to: dam construction and operation, river diversion, conversion of riparian wetland habitat by agriculture and urbanization, road construction, offhighway vehicle use, campground development, grazing, and mining. In each proposed critical habitat unit, special management may be needed to ensure that aquatic and terrestrial habitat are able to provide abundant breeding and non breeding habitat, prey habitat, shelter, and connectivity within the landscape.

In summary, we find that each of the areas we are proposing as revised critical habitat contains features essential to the conservation of the arroyo toad, and that these features may require special management considerations or protection. Special management considerations or protection may be required to eliminate, or reduce to negligible level, the threats affecting each unit and to preserve and maintain the essential features that the proposed critical habitat units provide to the arroyo toad. A more comprehensive discussion of threats facing individual sites is in the individual unit descriptions.

The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in the conservation of the arroyo toad. Activities with a Federal nexus that may affect those unprotected areas outside of critical habitat, such as development, agricultural activities, and road construction, are still subject to review under section 7 of the Act if they may affect the arroyo toad. The take prohibitions of section 9 of the Act also continue to apply both inside and outside of designated critical habitat. Take is broadly defined in the Act as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect a listed species, or to attempt to engage in any such conduct.

Criteria Used To Identify Critical Habitat

Using the best scientific and commercial data available as required by section 4(b)(1)(A) of the Act, we identified those areas to propose for revised designation as critical habitat that, within the geographical area occupied by the species at the time of listing (see ``Geographic Range'' section), possess those physical and biological features essential to the conservation of the arroyo toad and which may require special management considerations or protection. We also considered the area outside the geographical area occupied by the species at the time of listing for any areas that are essential for the conservation of the arroyo toad. The material we used included the 1994 final listing rule (59 FR 64859), the 2004 proposed critical habitat rule (69 FR 23254), 2008 CNDDB records, the arroyo toad recovery plan, data in reports submitted during section 7 consultations and by biologists holding section 10(a)(1)(A) recovery permits, research published in peerreviewed articles and presented in academic theses and agency reports, the 5year review for the arroyo toad (Service 2009, pp. 151), and regional GIS coverages. We analyzed this information to develop criteria for identifying areas that contain the PCEs in the appropriate quantity and spatial arrangement essential to the conservation of the arroyo toad that may require special management considerations or protection, or that are essential for the conservation of the arroyo toad.

To begin our analysis, we first examined the CNDDB current and historical records to get an indication of the habitat where arroyo toads are present or absent. The CNDDB is a continually refined and updated inventory of location information gathered during species surveys and observations. We then examined the arroyo toad recovery plan (Service 1999, pp. 1119), which has a recovery strategy focused on providing sufficient breeding and upland habitat to maintain self sustaining populations of arroyo toads (defined as populations that require little or no direct human assistance such as captive breeding or rearing, or translocation between sites) throughout the historical range of the species, and on minimizing or eliminating impacts and threats to arroyo toad populations (Service 1999, p. 67). The recovery plan states that instream and riparian habitats that support breeding, as well as upland habitats that provide foraging and overwintering habitat, need to be managed to maintain and enhance populations throughout the range of the arroyo toad (Service 1999, p. 68). The recovery plan divides the range of the arroyo toad into three large recovery unitsnorthern, southern, and desertand we considered the recovery of each of these as well as the species as a whole in our analysis. Using the recovery plan as our guide, we analyzed areas within the geographical area occupied by the arroyo toad at the time of listing to determine which areas contained the PCEs laid out in the appropriate quantity and spatial arrangement essential to the conservation of the species (the physical and biological features).

In determining the specific areas containing the essential physical and biological features, based on the recovery plan, 5year review, previous critical habitat proposals for the arroyo toad, scientific literature, and results of studies that have been conducted since the species was listed, we made sure that we are proposing critical habitat that will provide for the conservation of the species. Criteria we evaluated to assist our process include units: (1) That are dispersed throughout the current geographical, elevational, and ecological distribution of the species; (2) that would maintain the appropriate population structure across the species' range; (3) that retain or provide the connectivity between breeding sites that allows for the continued existence of essential metapopulations (a population of subpopulations in somewhat geographically isolated patches, interconnected through patterns of gene flow, extinction, and recolonization (Soule 1987, p. 7), despite fluctuations in the status of subpopulations); and (4) that contain upland habitat around each breeding location to allow for survival and recruitment to maintain a breeding population over the long term.

We also evaluated the area outside the geographical area occupied by the species at the time of listing to identify any areas that are essential for the conservation of the arroyo toad. We looked at areas that may have been historically occupied by arroyo toads based on CNDDB records but were no longer occupied at the time of listing. We also considered areas that may have the physical and biological features essential for the conservation of the species but have never been occupied. However, based on the best available scientific information, including the recovery plan which does not identify any such areas as being important to the recovery of the species, we determined that there are no areas outside the
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geograph

FOR FURTHER INFORMATION CONTACT

For general information on the proposed designation and information about the proposed revised designation in Santa Barbara and Ventura Counties, northern Los Angeles County, and the desert portion of San Bernardino County, contact Diane Noda, Field Supervisor, or Michael McCrary, Listing and Recovery Coordinator, Ventura Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2493 Portola Road, Suite B, Ventura, CA 93003; telephone (805) 6441766; facsimile (805) 6443958.

For information about the proposed revised designation in the remaining portions of Los Angeles and San Bernardino Counties, as well as Riverside, Orange, and San Diego Counties, contact Jim Bartel, Field Supervisor, Carlsbad Fish and Wildlife Office, U.S. Fish and Wildlife Service, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone (760) 4319440; facsimile (760) 4319624.

If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at (800) 8778339.