Federal Register: Part II [50 CFR Part 17]

DEPARTMENT OF THE INTERIOR

Veterans Employment and Training Service

CFR Citation: 50 CFR Part 17

NOTICE: Part II

DOCUMENT ACTION: Proposed rule.

SUBJECT CATEGORY: RIN-1018-AJ16

DATES: We will accept comments until June 14, 2004. Public hearing requests must be received by May 28, 2004.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to designate critical habitat for the California redlegged frog (Rana aurora draytonii) pursuant to the Endangered Species Act of 1973, as amended (Act). A total of approximately 1,674,582 hectares (4,138,064 acres) in Alameda, Butte, Contra Costa, El Dorado, Fresno, Kern, Los Angeles, Marin, Mariposa, Merced, Monterey, Napa, Plumas, Riverside, San Benito, San Diego, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, Tehama, Tuolumne, and Ventura Counties, California, is proposed for designation as critical habitat.

This proposed designation of critical habitat for the California redlegged frog is being published in accordance with the November 6, 2002, consent decree that ordered us to publish a proposal by March 2004. In light of this deadline, we have based this proposal solely on the configuration of our previously published final designation of critical habitat for the California redlegged frog (66 FR 14626, March 13, 2001). We hereby solicit data and comments from the public on all aspects of this proposal, incuding data on economic and other impacts of the designation.

We may revise this proposal prior to final designation to incorporate or address new information received during public comment periods or otherwise available to us.

SUMMARY: Interior Department, Fish and Wildlife Service,

DOCUMENT BODY 2:
Endangered and Threatened Wildlife and Plants; Proposed
Designation of Critical Habitat for the California Redlegged Frog (Rana aurora draytonii)

SUPPLEMENTAL INFORMATION

Public Comments Solicited

It is our intent that any final action resulting from this proposal will be as accurate as possible. Therefore, we solicit comments or suggestions from the public, other concerned governmental agencies, the scientific community, industry, or any other interested party concerning this proposed rule. On the basis of public comment, during the development of the final rule we may find that areas proposed are not essential, appropriate for exclusion under section 4(b)(2), or not appropriate for exclusion, in which case they would be removed from or made part of the final designation. We particularly seek comments concerning:
(1) The reasons why any areas should or should not be determined to be critical habitat as provided by section 4 of the Act, including whether the benefits of designation will outweigh any threats to the species resulting from the designation;
(2) Specific information on the amount and distribution of California redlegged frog and its habitat, and which habitat or habitat components are essential to the conservation of this species and why;
(3) Whether the primary constituent elements for the California redlegged frog as defined in this proposal are biologically and scientifically accurate, specifically,
(a) Whether aquatic habitat used for breeding must have a minimum deep water depth of 0.5 meters (m) (20 inches (in));
(b) Whether aquatic components must consist of two or more breeding sites located within 2 kilometers (km) (1.25 miles (mi)) of each other; (c) Should the primary constituent elements be more descriptive of the variations in habitat preference throughout the range of the subspecies;
(4) Whether the two recently discovered populations of California redlegged frogs in Youngs Creek, in Calaveras County, and in artificial ponds in Nevada County are essential to the conservation of the subspecies and should be included in designated critical habitat; (5) Land use designations and current or planned activities in or adjacent to the areas proposed and their possible impacts on proposed critical habitat;
(6) Any foreseeable economic or other potential impacts resulting from the proposed designation, in particular, any impacts on small entities;
(7) Some of the lands we have identified as essential for the conservation of the California redlegged frog are not being proposed as critical habitat. We specifically solicit comment on the inclusion or exclusion of such areas and:
(a) Whether these areas are essential;
(b) Whether these areas warrant exclusion; and
(c) The basis for not designating these areas as critical habitat (section 3(5)(A) or section 4(b)(2) of the Act);
(8) With specific reference to the recent amendments to sections 4(a)(3) and 4(b)(2) of the Act, we request information from the Department of Defense to assist the Secretary of the Interior in excluding critical habitat on lands administered by or under the [[Page 19621]]
control of the Department of Defense based on the benefit of an Integrated Natural Resources Management Plan (INRMP) to the conservation of the species; and information regarding impacts to national security associated with proposed designation of critical habitat; and
(9) Whether our approach to designating critical habitat could be improved or modified in any way to provide for greater public participation and understanding, or to assist us in accommodating public concerns and comments.

If you wish to comment, you may submit your comments and materials concerning this proposal by any one of several methods (see ADDRESSES section). Please submit electronic comments in ASCII file format and avoid the use of special characters or any form of encryption. Please also include ``Attn: RIN 1018AJ16'' in your email subject header and your name and return address in the body of your message. If you do not receive a confirmation from the system that we have received your Internet message, contact us directly by calling our Sacramento Fish and Wildlife Office at phone number 916/4146600. Please note that the email address fw1crlf@r1.fws.gov will be closed out at the termination of the public comment period. In the event that our Internet connection is not functional, please submit comments by the alternate methods mentioned above.

Our practice is to make comments, including names and home addresses of respondents, available for public review. Individual respondents may request that we withhold their home addresses from the rulemaking record, which we will honor to the extent allowable by law. There also may be circumstances in which we would withhold from the rulemaking record a respondent's identity, as allowable by law. If you wish us to withhold your name and/or address, you must state this prominently at the beginning of your comment. However, we will not consider anonymous comments. We will make all submissions from organizations or businesses, and from individuals identifying themselves as representatives or officials of organizations or businesses, available for public inspection in their entirety. Comments and materials received will be available for public inspection, by appointment, during normal business hours at the above address. Preamble
Designation of Critical Habitat Provides Little Additional Protection to Species

In 30 years of implementing the Act, the Service has found that the designation of statutory critical habitat provides little additional protection to most listed species, while consuming significant amounts of conservation resources. The Service's present system for designating critical habitat is driven by litigation rather than biology, limits our ability to fully evaluate the science involved, consumes enormous agency resources, and imposes huge social and economic costs. The Service believes that additional agency discretion would allow our focus to return to those actions that provide the greatest benefit to the species most in need of protection.
Role of Critical Habitat in Actual Practice of Administering and Implementing the Act

While attention to and protection of habitat is paramount to successful conservation actions, we have consistently found that, in most circumstances, the designation of critical habitat is of little additional value for most listed species, yet it consumes large amounts of conservation resources. Sidle (1987) stated, ``Because the ESA [Act] can protect species with and without critical habitat designation, critical habitat designation may be redundant to the other consultation requirements of section 7.''

Currently, only 445 or 36 percent of the 1244 listed species in the U.S. under the jurisdiction of the Service have designated critical habitat (Service 2004). We address the habitat needs of all 1244 listed species through conservation mechanisms such as listing, section 7 consultations, the Section 4 recovery planning process, the Section 9 protective prohibitions of unauthorized take, Section 6 funding to the States, and the Section 10 incidental take permit process. The Service believes that it is these measures that may make the difference between extinction and survival for many species.
Procedural and Resource Difficulties in Designating Critical Habitat

We have been inundated with lawsuits regarding critical habitat designation, and we face a growing number of lawsuits challenging critical habitat determinations once they are made. These lawsuits have subjected the Service to an everincreasing series of court orders and courtapproved settlement agreements, compliance with which now consumes nearly the entire listing program budget. This leaves the Service with little ability to prioritize its activities to direct scarce listing resources to the listing program actions with the most biologically urgent species conservation needs.

The consequence of the critical habitat litigation activity is that limited listing funds are used to defend active lawsuits and to comply with the growing number of adverse court orders. As a result, the Service's own to proposals to undertake conservation actions based on biological priorities are significantly delayed.

The accelerated schedules of courtordered designations have left the Service with almost no ability to provide for additional public participation beyond those minimally required by the Administrative Procedure Act (APA), the Act, and the Service's implementing regulations, or to take additional time for review of comments and information to ensure the rule has addressed all the pertinent issues before making decisions on listing and critical habitat proposals, due to the risks associated with noncompliance with judicially imposed deadlines. This in turn fosters a second round of litigation in which those who will suffer adverse impacts from these decisions challenge them. The cycle of litigation appears endless, is very expensive, and in the final analysis provides little additional protection to listed species.

The costs resulting from the designation include legal costs, the cost of preparation and publication of the designation, the analysis of the economic effects and the cost of requesting and responding to public comment, and in some cases the costs of compliance with National Environmental Policy Act (NEPA); all are part of the cost of critical habitat designation. These costs result in minimal benefits to the species that are not already afforded by the protections of the Act enumerated earlier, and they directly reduce the funds available for direct and tangible conservation actions.
Background

Species Description

The California redlegged frog (Rana aurora draytonii) is the largest native frog in the western United States. It is endemic to California and Baja California, Mexico. It is typically found from sea level to elevations of approximately 1,500 meters (m) (5,000 feet (ft)). The California redlegged frog ranges in body length from 40 to 130 millimeters (mm) (1.6 to 5.1 in), with
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adult females attaining a significantly longer body length than males (138 mm (5.4 in) versus 116 mm (4.6 in)) (Hayes and Miyamoto 1984). The posterior abdomen and hind legs of adults vary in color, but are often red or salmon pink; the back is characterized by small black flecks and larger irregular dark blotches with indistinct outlines on a brown, gray, olive, or reddishbrown background. Dorsal spots usually have light centers (Stebbins 1985), and the dorsolateral folds (folds along the sides of the frog) are prominent. Larvae range from 14 to 80 mm (0.6 to 3.1 in) in length, and the background color of the body is dark brown or olive with darker spots (Storer 1925). A line of very small, indistinct goldcolored spots are thought to become the dorsolateral fold. The California redlegged frog is one of two subspecies of the redlegged frog (R. aurora). For a detailed description of the two subspecies, see the Recovery Plan for the California Redlegged Frog (Service 2002) and references identified within the plan.

Life History

Male California redlegged frogs appear at breeding sites 2 to 4 weeks before females (Storer 1925). A pair in amplexus (breeding position) moves to an oviposition site (the location where eggs are laid), and the eggs are fertilized while being attached to a brace. Braces include emergent vegetation such as bulrushes (Scirpus sp.), cattails (Typha sp.), or roots and twigs, although breeding has been documented in ponds without emergent vegetation (Steven Bobzien in litt. 2001). Each mass contains about 2,000 to 5,000 individual eggs measuring approximately 2.0 to 2.8 mm (0.08 to 0.11 in) in diameter. Eggs hatch in 6 to 14 days depending on water temperatures (Jennings et al., 1992). Larvae typically metamorphose between July and September 3.5 to 7 months after eggs are laid (Storer 1925; Wright and Wright 1949). However, several researchers have recently observed larvae to overwinter in Contra Costa, Marin, Santa Clara, and San Luis Obispo Counties (Bobzien et al. 2000), and possibly in Ventura County (R. Smith, Los Angeles Zoo, in litt. 2001), with new metamorphs being observed in March and April.

Of the various life stages, larvae probably experience the highest mortality rates. Survival rate from hatching to metamorphosis (the process of changing from a tadpole to a frog) has been estimated as less than 1 percent (Jennings et al. 1992), 1.9 percent (Cook 1997), or less than 5 percent (Lawler et al. 1999) for California redlegged frog tadpoles cooccurring with bullfrog tadpoles, and 30 to 40 percent for California redlegged frog tadpoles occurring without bullfrogs (Lawler et al. 1999). Sexual maturity can be attained at 2 years of age by males and 3 years of age by females (Jennings and Hayes 1985), with adults living 8 to 10 years (Jennings, U.S. Geological Survey (USGS), Biological Resources Division (BRD), pers. comm. 2000). However, the average life span is probably much lower (Scott, USGS, BRD, pers. comm. 2000).

Geographic Range

The historic range of the California redlegged frog extended along the coast from the vicinity of Point Reyes National Seashore, Marin County, California, and inland from the vicinity of Redding, Shasta County, California, southward to northwestern Baja California, Mexico (Jennings and Hayes 1985; Hayes and Krempels 1986). California red legged frogs have been documented in 46 counties in California, but now remain in only 248 streams or drainages in 26 counties; the subspecies has lost approximately 70 percent of its former range (61 FR 25813, May 23, 1996). California redlegged frogs are still locally abundant within portions of the San Francisco Bay area (including Marin County) and the central coast. Within the remaining distribution of the subspecies, only isolated populations have been documented in the Sierra Nevada, northern Coast, and northern Transverse ranges. The subspecies was previously believed to be extirpated (exterminated) from most of its range in the southern Transverse and Peninsular Ranges, but two additional populations have recently been discovered. The species is still present in Baja California, Mexico (California Natural Diversity Data Base (CNDDB) 1998; Service, in litt. 2003).

Threats

The California redlegged frog was listed as a threatened subspecies on May 23, 1996 (61 FR 25813). Habitat loss and alteration, overexploitation, and introduction of exotic predators were significant factors in the subspecies' decline in the earlytomid1900s. Reservoir construction, expansion of introduced predators, management of grazing in riparian areas resulting in loss of stream bank habitat and plunge pools, and prolonged drought fragmented and eliminated many of the Sierra Nevada foothill populations. Only a few drainages currently support California redlegged frogs in the Sierra Nevada foothills, compared to more than 60 historical records. In Northern California, few California redlegged frog populations occupy naturally occurring wetland environments. As natural wetlands and streams were converted for agriculture, flood control, and urban development, California red legged frogs colonized small artificial impoundments created by cattle ranchers for the purpose of providing water for their cattle. Without these impoundments, the range of California redlegged frogs would be limited further in this region.

Several researchers have attributed the decline and extirpation of California redlegged frogs to the introduction of bullfrogs (Rana catesbeiana) and predatory fishes (Hayes and Jennings 1986; Moyle 1973). This decline has been attributed to both predation and competition. Twedt (1993) observed the predation of juvenile northern redlegged frogs (R. aurora aurora) and suggested that bullfrogs may prey on subadult redlegged frogs. This is supported by Cook (Sonoma County Water Agency, in litt. 2000) and David Cook and M. Jennings (in litt. 2000), who documented bull frog predation of both tadpoles and juvenile California redlegged frogs, as well as a large adult, by bullfrogs. In addition, bullfrogs may have a competitive advantage over redlegged frogs. Bullfrogs are larger, have more generalized food habits (Bury and Whelan 1984), and have an extended breeding season (Storer 1933) during which an individual female produces as many as 20,000 eggs (Emlen 1977). Further, bullfrog larvae are unpalatable to predatory fish (Kruse and Francis 1977). Bullfrogs also interfere with redlegged frog reproduction. Both California and northern redlegged frogs have been observed in amplexus with both male and female bullfrogs (Twedt 1993; Service files).

California redlegged frogs are currently threatened by human activities, many of which operate concurrently and cumulatively with each other and with natural disturbances (e.g., droughts and floods). Current factors associated with declining populations of the frog include degradation and loss of habitat through urbanization, mining, improper management of grazing, recreation, invasion of nonnative plants, impoundments, water diversions, degraded water quality, and introduced predators. These factors have resulted in the isolation and fragmentation of habitats within many watersheds, often precluding dispersal between subpopulations and jeopardizing the viability of metapopulations (broadly defined as multiple subpopulations that occasionally exchange individuals through dispersal and are capable of [[Page 19623]]
colonizing or rescuing habitat patches when the local subpopulations have been extirpated). The fragmentation of existing habitat, and the continued colonization of existing habitat by nonnative species, may represent the most significant current threats to California redlegged frogs.

Numerous studies have demonstrated the impacts of fragmentation on other anuran (frog and toad) species. Urban populations of common frogs (Rana temporaria) were more genetically distinct than rural populations (Hitchins and Beebee 1997). Based on genetic analysis, Reh and Seitz (1990) found that highways effectively isolated R. temporaria populations. Kuhn (1987, in Reh and Seitz 1990) estimated that 24 to 40 cars per hour killed 50 percent of common toad (Bufo bufo) individuals migrating across a road, while Heine (1987, in Reh and Seitz 1990) found that 26 cars per hour could reduce the survival rate of toads crossing roads to zero. In addition, Fahrig et al. (1995) found a significant negative correlation between traffic density and the density of anuran populations. Thus, heavily traveled roads are an important humancaused landscape component, hindering amphibian movement through vehicle strikes and thereby fragmenting amphibian populations.

In addition to the fragmentation of habitat, activities that occur on upland habitats can have both direct and indirect significant deleterious impacts on California redlegged frogs. For example, amphibian speciesrichness (number of species in an area) is related to land use in the watersheds of Puget Sound, Washington (Richter and Azous 1995, 1997); speciesrichness was significantly lower in watersheds where more than 40 percent of the land area was developed. This was attributed to increases in the total water level fluctuations within wetlands (e.g., both increases in the number of fluctuations of water levels within the wetland and increases in the magnitude of fluctuations). Specifically, urbanization leads to higher peak flows and volumes, resulting in increases in the magnitude, frequency, and duration of wetland hydroperiods and stream levels (Reinalt and Taylor 1997). Urbanization within the range of the California redlegged frog often results in similar effects on wetlands.

Urbanization results in additional water runoff sources into wetlands and stream courses associated with irrigation and home use activities, especially during the summer months. This often drastically alters the hydroperiod and converts intermittent streams and seasonal wetlands to perennial aquatic habitat. Such alteration allows nonnative species such as bullfrogs and nonnative warm water fish species to invade the habitat and further adversely affect California redlegged frog populations. California redlegged frogs are rarely found in areas where a large majority of the watershed has been developed (H.T. Harvey and Associates 1997, Service files). This is further supported by Schueler (1994), who summarized research examining macroinvertebrate and fish diversity. Those results illustrated the difficulty of maintaining predevelopment stream quality when watershed development exceeds 1015 percent impervious cover. For example, Klein (1979, in Schueler 1994) found that macroinvertebrate diversity consistently became poor when watershed imperviousness exceeded 10 to 15 percent; this has been supported by Schueler and Galli (1992 in Schueler 1994) and Shaver et al. (1994, in Schueler 1994). This loss of diversity has also been observed in fish (Klein 1979; Limburg and Schmidt 1990, both in Schueler 1994).

In addition to the modification of hydroperiod, impacts within the watershed can also affect water and habitat quality. As watersheds are developed, the area of impervious surface increases, resulting in an increase of sediments containing organic matter, pesticides and fertilizers, heavy metals, hydrocarbons, and other debris entering streams and wetlands (U.S. Environmental Protection Agency (EPA) 1993). Skinner et al. (1999) found developed watersheds had greater concentrations of toxic effluents than less developed areas with more open space. The decrease in water quality can have profound impacts on native amphibians and other wetland vertebrates. Richter and Azous (1997) observed that wetlands adjacent to undeveloped upland areas were more likely to have richer populations of native amphibians. Mensing et al. (1998) found that amphibian abundance was negatively influenced by land use at small scales (e.g., within 0.5 to 1.0 km (0.30 to 0.60 mi).

Habitat fragmentation, wetland conversions, and hydrological alterations cumulatively result in changes in wetland species composition, including amphibian composition. Amphibian declines can be attributed to increasing numbers of nonnative competitors and predators capable of thriving in disturbed conditions (Harris 1998). Onorato et al. (1998) found native fish species were sensitive to anthropogenic disturbances and were becoming less abundant within the study area. They also found introduced generalists able to tolerate lower quality habitat and to replace native fish species within the system. This scenario has been demonstrated in Santa Clara Valley, California, where the loss of California redlegged frog populations was attributed in part to the invasion of bullfrogs into urbanized areas (H.T. Harvey and Associates 1997).

Climate

California redlegged frogs are adapted to survive in a Mediterranean climate where habitat quality varies spatially and temporally. Due to this variability, population sizes can vary widely from year to year. During favorable years, California redlegged frogs can experience extremely high rates of reproduction and produce large numbers of dispersing young, resulting in an increase in the number of occupied sites. In contrast, frogs may temporarily disappear from an area during periods of extended drought. Therefore, it is important for the longterm survival and recovery of the species to protect those sites that appear to be unoccupied, but can be recolonized by dispersing individuals from nearby subpopulations (Semlitsch 2000). Habitat

California redlegged frogs use a variety of habitat types, including various aquatic, riparian, and upland habitats. They include, but are not limited to, ephemeral ponds, intermittent streams, seasonal wetlands, springs, seeps, permanent ponds, perennial creeks, manmade aquatic features, marshes, dune ponds, lagoons, riparian corridors, blackberry (Rubus sp.) thickets, nonnative annual grasslands, and oak savannas. Among the variety of habitats where California redlegged frogs have been found, the only common factor is association with a permanent water source. Apparently, California redlegged frogs can use virtually any aquatic system, provided a permanent water source, ideally free of nonnative predators, is nearby. Permanent water sources can include, but are not limited to, ponds, perennial creeks (or permanent plunge pools within intermittent creeks), seeps, and natural and artificial springs. California redlegged frogs may complete their entire life cycle in a particular area (i.e., a pond that is suitable for all life stages) or utilize multiple habitat types. These variable lifehistory characteristics enable California redlegged frogs to change habitat use in response to
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varying conditions. During a period of abundant rainfall, the entire landscape may become suitable habitat. Conversely, habitat use may be drastically confined during periods of prolonged drought.

Populations of California redlegged frogs are most likely to persist where multiple breeding areas are within an assemblage of habitats used for dispersal (N. Scott and G. Rathbun in litt. USGS, BRD, 1998), a trait typical of many frog and toad species (Laan and Verboom 1990; Reh and Seitz 1990; Mann et al. 1991; SjogrenGulve 1994; Griffiths 1997; Marsh et al. 1999). Breeding sites have been documented in a variety of aquatic habitats. Larvae, juveniles, and adult frogs have been observed inhabiting streams, creeks, ponds, marshes, sag ponds, deep pools, and backwaters within streams and creeks, dune ponds, lagoons, estuaries, and artificial impoundments, such as stock ponds. Furthermore, breeding has been documented in these habitat types irrespective of vegetation cover. Frogs successfully breed in artificial ponds with little or no emergent vegetation (S. Bobzien in litt. 2000), and have been observed to successfully breed and inhabit stream reaches that are not cloaked in riparian vegetation (Bobzien et al. 2000). The importance of riparian vegetation for this subspecies is not well understood. It is believed that riparian plant communities provide good foraging habitat due to the moisture and camouflage that occur within the community, as well as providing areas for dispersal and supporting pools and backwater aquatic areas for breeding. However, other factors are more likely to influence the suitability of aquatic breeding sites, such as the general lack of introduced aquatic predators.

California redlegged frogs often disperse from their breeding habitat to utilize various aquatic, riparian, and upland estivation habitats in the summer; however, it is also common for individuals to remain in the breeding area on a yearround basis. Frogs use a number of habitat features, including ponds, streams, marshes, boulders or rocks, organic debris such as downed trees or logs, industrial debris, and agricultural features such as drains, watering troughs, or spring boxes. When riparian habitat is present, frogs spend considerable time resting and feeding in the vegetation (G. Rathbun in litt. 2000). When riparian habitat is absent, frogs spend considerable time resting and feeding under rocks and ledges, both in and out of water (Trish Tatarian, Sonoma State University, Sonoma County in litt. 2000). California redlegged frogs can also use small mammal burrows and moist leaf litter (Jennings and Hayes 1994). Stream channels with portions narrower and deeper than 46 centimeters (cm) (18 in) may also provide habitat (61 FR 25813). This type of dispersal and habitat use is not observed in all California redlegged frogs, however, and is likely dependent on the yeartoyear variations in climate and habitat suitability and varying requirements of each life stage.

Dispersal

At any time of the year, adult California redlegged frogs may move from breeding sites. They can be encountered living within streams at distances exceeding 2.9 km (1.8 mi) from the breeding site and have been found farther than 100 m (328 ft) from water in adjacent dense riparian vegetation. The California redlegged frog has been observed inhabiting riparian areas for up to 77 days (J. Bulger et al., USGS, BRD, in litt. 2000), but typically remains within 60 m (200 ft) of water. During periods of wet weather, starting with the first rains of fall, some individuals may make overland excursions through upland habitats. Most of these overland movements occur at night. Evidence from marked adult frogs on the San Simeon coast of San Luis Obispo County, California, suggests that frog movements of about 1.6 km (1 mi), over upland habitats, are possible over the course of a wet season (N. Scott and G. Rathbun, in litt. 1998). Frogs will make long distance, straightline, pointtopoint movements rather than using corridors for moving between habitats (N. Scott and G. Rathbun, in litt. 1998). Dispersing adult frogs in northern Santa Cruz County traveled distances from 0.4 km (0.25 mi) to more than 3.2 km (2 mi) without apparent regard to topography, vegetation type, or riparian corridors (J. Bulger, in litt. 2000). Many newly metamorphosed juveniles tend to disperse short distances initially from July through September, and then move farther away from the breeding habitat during warm rain events (Monk 1997a; M. Jennings in litt. 2000; N. Scott in litt. 2000; Brian Mori in litt. 2000). Bobzien et al. (2000) observed juveniles inhabiting a wide variety of habitats while adults primarily inhabited deep pools; and they postulated that juveniles might segregate themselves away from adults to escape predation and competition.

The dispersal capabilities of juveniles have not been studied, but are likely dependent upon rainfall and moisture levels during and immediately following dispersal events and on habitat availability and environmental variability. There is anecdotal evidence that juvenile redlegged frogs disperse at least 1 km (0.6 mi) away from breeding habitat. These data are the result of consulting biologists conducting surveys for California tiger salamanders (Ambystoma californiense) in eastern Alameda (Monk and Associates 1997a and 1997b) and Santa Clara Counties (B. Mori, in litt. 2000). In both locations, newly metamorphosed California redlegged frogs were found dispersing away from breeding habitat during rain events. The ability of juveniles and adults to disperse is important for the longterm survival and recovery of the subspecies because the dispersing individuals can recolonize areas subjected to localized extirpation.

The manner in which nondispersing California redlegged frogs use upland habitats is not well understood. The length of time California redlegged frogs spend in upland habitats, patterns of use, and whether juveniles, subadults, and adults use uplands differently are under study. Preliminary data from San Simeon and Pico creeks in central California indicated that the number of days when California redlegged frogs were found more than 2.0 m (7 ft) from water ranged from 0 to 56 days (G. Rathbun, in litt. 2000), while the majority of California red legged frogs observed in eastern Contra Costa County spent the entire wet season within streamside habitat (T. Tatarian, in litt. 2000). However, several frogs have been documented moving away from the streamside habitat for varying periods (T. Tatarian, pers. comm. 2001).

The healthiest California redlegged frog populations persist as a collection of subpopulations that exchange genetic information through individual dispersal events. These populations persist and flourish where suitable breeding and nonbreeding habitats are interspersed throughout the landscape and are interconnected by unfragmented dispersal habitat. Where this habitat mosaic exists, local extirpations may be counterbalanced by the colonization of new habitat or recolonization of unoccupied areas of suitable habitat. Studies on other frogs and toads have demonstrated that the probability of a habitat being occupied is positively correlated with the distance to the nearest currently occupied habitat patch (Laan and Verboom 1990; Mann et al. 1991; Marsh et al. 1999). Isolated patches far removed from occupied patches eventually became extirpated (SjogrenGulve 1994). In addition to distance between habitat patches, the fragmentation of dispersal routes can also result in the isolation of subpopulations. Studies from other
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anuran species have shown that fragmentation has resulted in problems associated with inbreeding (Reh and Seitz 1990; Hitchings and Beebee 1997) and an increase in unoccupied suitable habitat, and can ultimately result in extinction (SjogrenGulve 1994).

The longterm probability of the survival and recovery of California redlegged frogs is dependent upon the protection of existing breeding habitat, the movements of individuals between aquatic patches, and the ability to recolonize newly created or vacated habitats. Recolonization, which is vital to the recovery of this subspecies, is dependent upon landscape characteristics including the distance between patches, the number and severity of barriers between patches, and the presence of interconnecting elements (e.g., habitat where frogs can rehydrate), and upon the dispersal capability of California redlegged frogs (Laan and Verboom 1990).

Since the publication of our last designation of critical habitat for the California redlegged frog on March 13, 2001 (66 FR 14626), two new populations of the subspecies have been documented. However, due to limited access to these populations since they occur on private property and the limited information we have concerning their status, we have not been able to make a determination at this time as to whether they are essential to the conservation of the subspecies. We specifically seek information concerning these two new populations to assist us in making that determination. If, upon receipt of additional data and further analysis, we determine these populations to be essential to the conservation of the subspecies, it would be our intention to include them in final critical habitat.

The first population was discovered on private property in the South Fork Yuba River watershed in Nevada County, California, in 2002. This presence of this population was subsequently confirmed by Sacramento Fish and Wildlife staff in 2003. During the site visit, California redlegged frog tadpoles were observed suggesting the presence of a breeding population. Further, during this site visit, there was no specific evidence visible of invasive or predatory species on site. The California redlegged frogs on this site occur in artificial ponds, but they are not active stock ponds. Because this population is located on private land, we have not had the opportunity to study it. Consequently, we are not able to make any specific conclusions regarding the status of this population of the subspecies at this locale.

A second population of California redlegged frogs was discovered on private land in Youngs Creek, Calaveras County, California, in 2003. The population was subsequently confirmed, but due to limited access, we have not been able to determine the extent of this population. Youngs Creek is a tributary of Cosgove Creek, a tributary to Calaveras River; however, during the site visits, there was no specific evidence visible of invasive or predatory species bullfrogs are known to occur in ponds on adjacent property.

Previous Federal Action

On February 2, 1994, we published a proposal to list the frog as an endangered species (59 FR 4888). Based on information provided during the public comment period, we subsequently published a final rule listing the California redlegged frog as threatened on May 23, 1996 (61 FR 25813). At the time of the final listing, we determined that designating critical habitat was not prudent due to the potential increased degree of threat from the publication of specific localities. This specific information would make the species more vulnerable to vandalism and also to collection for market consumption. Consequently, we did not designate critical habitat for the subspecies.

On March 24, 1999, the Earthjustice Legal Defense Fund, on behalf of the Jumping Frog Research Institute, the Southwest Center for Biological Diversity, and the Center for Sierra Nevada Conservation, filed a lawsuit in the Northern District of California on our failure to designate critical habitat for the California redlegged frog.

On December 15, 1999, the court ordered us to make a prudency determination by August 31, 2000, and issue a final rule by December 29, 2001. On January 18, 2000, the court clarified an error in the December 15, 1999, order stating that the Service shall issue a final rule by December 29, 2000. On August 22, 2000, we submitted a declaration requesting an extension of the court order to March 1, 2001, citing the need to extend the comment period. On September 11, 2000, we published a proposed rule to designate approximately 2,175,000 ha (5,373,650 ac) as critical habitat for the California redlegged frog (65 FR 54891) in California. The comment period was open until October 11, 2000. During this comment period, four public hearings were held in Ventura (September 19, 2000), San Luis Obispo (September 21, 2000), Dublin (September 26, 2000), and Sacramento (September 28, 2000). On December 21, 2000, we published a notice (65 FR 80409) announcing the reopening of the comment period on the proposal to designate critical habitat for the California redlegged frog and a notice of availability of the draft economic analysis on the proposed determination. The comment period was reopened until January 22, 2001. A final rule designating critical habitat for the California redlegged frog was signed on March 1, 2001, and published in the Federal Register on March 13, 2001 (66 FR 14626).

On June 8, 2001, the Home Builders Association of Northern California, California Chamber of Commerce, California Building Industry Association, California Alliance for Jobs, and the Building Industry Legal Defense Fund filed a lawsuit in the U.S. District Court for the District of Columbia challenging the Service's designation of critical habitat for the California redlegged frog. Home Builders Ass'n of Northern California, et al. v. Norton, et al., Civ. No. 01 1291 (RJL) (D. D.C.). On November 6, 2002, the court entered a consent decree remanding the designation to the Service to conduct an economic analysis in accordance with the Tenth Circuit's decision in New Mexico Cattle Growers Ass'n v. U.S. Fish and Wildlife Service, 248 F.3d 1277 (10th Cir. 2001). The consent decree vacated the critical habitat designation for the California redlegged frog with the exception of Units 5 and 31, Units not known to be occupied by the frog, and ordered the Service to promulgate a proposed revised designation by March 2004, and a final revised rule by November 2005. This proposed rule is published in accordance with the November 6, 2002, consent decree. Critical Habitat

Section 3(5)(A) of the Act defines critical habitat as(i) the specific areas within the geographic 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 (I) essential to the conservation of the species and (II) that may require special management considerations or protection; and (ii) specific areas outside the geographic 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'' means the use of all methods and procedures that are necessary to bring an endangered or a threatened species to the point at which listing under the Act is no longer necessary.

The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve,
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preserve, or other conservation area. It does not allow government or public access to private lands. Under section 7 of the Act, Federal agencies must consult with us on activities they undertake, fund, or permit that may affect critical habitat and lead to its destruction or adverse modification. However, the Act prohibits unauthorized take of listed species and requires consultation for activities that may affect them, including habitat alterations, regardless of whether critical habitat has been designated. We have found that the designation of critical habitat provides little additional protection to most listed species.

To be included in a critical habitat designation, habitat must be either a specific area within the geographic area occupied by the species on which are found those physical or biological features essential to the conservation of the species (primary constituent elements, as defined at 50 CFR 424.12(b)) and which may require special management considerations or protections, or be specific areas outside of the geographic area occupied by the species which are determined to be essential to the conservation of the species. Section 3(5)(C) of the Act states that not all areas that can be occupied by a species should be designated as critical habitat unless the Secretary determines that all such areas are essential to the conservation of the species. Our regulations (50 CFR 424.12(e)) also state that, ``The Secretary shall designate as critical habitat areas outside the geographic area presently occupied by the species only when a designation limited to its present range would be inadequate to ensure the conservation of the species.'' Regulations at 50 CFR 424.02(j) define special management considerations or protection to mean any methods or procedures useful in protecting the physical and biological features of the environment for the conservation of listed species. When we designate critical habitat, we may not have the information necessary to identify all areas that are essential for the conservation of the species. Nevertheless, we are required to designate those areas we consider to be essential, using the best information available to us. Accordingly, we do not designate critical habitat in areas outside the geographic area occupied by the species unless the best available scientific and commercial data demonstrate that unoccupied areas are essential for the conservation needs of the species.

Section 4(b)(2) of the Act requires that we take into consideration the economic, national security, and any other relevant impact, of specifying any particular area as critical habitat. We may exclude areas from critical habitat designation when the benefits of exclusion outweigh the benefits of including the areas within critical habitat, provided the exclusion will not result in extinction of the species.

Our Policy on Information Standards Under the Endangered Species Act, published in the Federal Register on July 1, 1994 (59 FR 34271) and our U.S. Fish and Wildlife Service Information Quality Guidelines (2002) provide criteria, establish procedures, and provide guidance to ensure that our decisions represent the best scientific and commercial data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific and commercial data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat. When determining which areas are critical habitat, a primary source of information should be the listing package for the species. Additional information may be obtained from a recovery plan, articles in peer reviewed 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.

Section 4 of the Act requires that we designate critical habitat on the basis of what we know at the time of designation. Habitat is often dynamic, and species may move from one area to another over time. Furthermore, we recognize that designation of critical habitat may not include all of the habitat areas that may eventually be determined to be necessary for the recovery of the species. For these reasons, critical habitat designations do not signal that habitat outside the designation is unimportant or may not be required for recovery.

Areas that support populations of a listed species, but are outside the designation of critical habitat for it, will continue to be subject to conservation actions implemented under section 7(a)(1) of the Act and 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 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, or other species conservation planning efforts if new information available to these planning efforts calls for a different outcome.

Methods

In identifying areas that are essential to conserve the California redlegged frog, we used the best scientific and commercial data available. These included data from research and survey observations published in peerreviewed articles, recovery criteria and strategy outlined in the Recovery Plan (Service 2002), regional Geographic Information System (GIS) watershed and species coverages, data compiled in the California Natural Diversity Database (CNDDB), data and analysis used to develop regional Habitat Conservation Plans (HCPs), and data collected from reports submitted by biologists holding section 10(a)(1)(A) recovery permits. In the development of this proposal, we also took into consideration any information provided to us during the public comment periods on our previous proposed critical habitat designation (65 FR 54891, September 11, 2000) and draft economic analysis of our proposed critical habitat (65 FR 80409, December 21, 2000).

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12, in determining which areas to designate as critical habitat, we are required to consider those physical and biological features (primary constituent elements) that are essential to the conservation of the species, and that may require special management considerations and protection. These include, but are not limited to, space for individual and population growth and for normal behavior; food, water, air, light, minerals, or other nutritional or physiological requirements; cover or shelter; sites for breeding, reproduction, rearing (or development) of offspring; and habitats that are protected protection from disturbance or are representative of the historic geographical and ecological distributions of a species.

Due to the complex life history and dispersal capabilities of the California redlegged frog, and the dynamic nature of the environments in which they are found, the primary constituent elements described below are found throughout the watersheds that are being designated as critical habitat. Special management, such as habitat rehabilitation efforts (e.g., removal of nonnative predators),
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may be necessary throughout the area being proposed for designation. Critical habitat for California redlegged frogs will provide for breeding and nonbreeding habitat and for dispersal between these habitats, as well as allowing for expansion of frog populations, which is essential to the conservation of the subspecies.

Critical habitat includes: (a) Essential aquatic habitat; (b) associated uplands; and (c) dispersal habitat connecting essential aquatic habitat.

Breeding and Foraging Habitat

Aquatic habitat is essential for providing space, food, and cover, necessary to sustain all life stages of California redlegged frogs. It consists of virtually all lowgradient fresh water bodies, including natural and manmade (e.g., stock) ponds, backwaters within streams and creeks, marshes, lagoons, and dune ponds, except for deep lacustrine water habitat (e.g., deep lakes and reservoirs 20 ha (50 ac) or larger in size) inhabited by nonnative predators. The subspecies requires a permanent water source to ensure that aquatic habitat is available year round. Permanent water sources can include, but are not limited to, ponds, perennial creeks (or permanent plunge pools within intermittent creeks), seeps, and springs. Aquatic habitat used for breeding must have a minimum deep water depth of 0.5 m (20 in) and maintain water during the entire tadpole rearing season (at least March through July). During periods of drought, or lessthanaverage rainfall, these breeding sites may not hold water long enough for individuals to complete metamorphosis, but these sites would still be considered essential breeding habitat in wetter years. Ponds that support a small population of California redlegged frogs, but are not surrounded by suitable upland habitat, or are cut off from other breeding ponds or permanent water sources by impassable dispersal barriers, do not have the primary constituent elements for California redlegged frog critical habitat.

To be a primary constituent element for California redlegged frog critical habitat, the aquatic components must consist of two or more breeding sites located within 2 km (1.25 mi) of each other; at least one of the breeding sites must also be a permanent water source. Also, the aquatic component can consist of two or more seasonal breeding sites with a permanent nonbreeding water source located within 2 km (1.25 mi) of each breeding site. California redlegged frogs have been documented to travel 3.6 km (2.25 mi) in a virtual straightline migration from nonbreeding to breeding habitats (J. Bulger, in litt. 2000). We believe that this is likely the upward limit of dispersal capability and that the 2km (1.25mi) dispersal element will ensure that connectivity between breeding habitats will be maintained within areas designated as critical habitat. In addition, breeding sites must be connected by essential dispersal habitat, described below. Associated Upland Habitat For Forage, Shelter, Water Quality Maintenance

Associated upland and riparian habitat is essential to maintain California redlegged frog populations associated with essential aquatic habitat. The associated uplands and riparian habitat provide food and shelter sites for California redlegged frogs and assist in maintaining the integrity of aquatic sites by protecting them from disturbance and supporting the normal functions of the aquatic habitat. The palustrine or emergent aquatic habitat is often characterized by presence of cattail (Typha spp.), bulrush (Scirpus spp.), and other persistent emergent vegetation that allows for shelter, forage, and attachment of egg masses, while the associated adjacent upland habitat often contains blackberry (Rubus sp.) and other upland perennial species that provide for shelter from predatory species and forage habitat (Service 2002).

Key conditions include the timing, duration, and extent of water moving within the system, filtering capacity, and maintaining the habitat to favor California redlegged frogs and discourage the colonization of nonnative species such as bullfrogs. Essential upland habitat consists of all upland areas within 90 m (300 ft) of the edge of the ordinary highwater mark, or no further than the watershed boundary. This is based, in part, on the work of J. Bulger et al. (in litt. 2000), who found that frogs were capable of inhabiting upland habitats within 60 m (200 feet) of aquatic habitat for continuous durations exceeding 20 days, and G. Rathbun (in litt. 2000), who observed frogs inhabiting riparian habitat for durations exceeding 30 days.

Dispersal Habitat

Essential dispersal habitat provides connectivity among California redlegged frog breeding habitat (and associated upland) patches. While frogs can pass many obstacles, and do not require a particular type of habitat for dispersal, the habitat connecting essential breeding locations and other aquatic habitat must be free of barriers (e.g., a physical or biological feature that prevents frogs from dispersing beyond the feature) and at least 90 m (300 ft) wide. Essential dispersal habitat consists of all upland and wetland habitat free of barriers that connects two or more patches of essential breeding habitat within 2 km (1.25 mi) of one another. Dispersal barriers include heavily traveled roads (an average of 30 cars per hour from 10 p.m. to 4 a.m.) that possess no bridges or culverts; moderate to high density urban or industrial developments; and large reservoirs over 20 ha (50 ac) in size. Agricultural lands such as row crops, orchards, vineyards, and pastures do not constitute barriers to California red legged frog dispersal.

In summary, the primary constituent elements for the California redlegged frog consist of three components:
(1) Aquatic habitat with a permanent water source with pools (i.e., water bodies) having a minimum depth of 0.5 m (20 in) for breeding and which can maintain water during the entire tadpole rearing season; (2) Upland areas up to 90 m (300 ft) from the water's edge associated with the above aquatic habitat that will provide for shelter, forage, maintenance of the water quality of the aquatic habitat, and dispersal; and
(3) Upland barrierfree dispersal habitat that is at least 90 m (300 ft) in width that connect at least two (or more) suitable breeding locations defined by the aquatic habitat above, all within 2 km (1.25 miles) of one another.

Criteria Used To Identify Critical Habitat

We considered several criteria in the selection and proposal of specific boundaries for California redlegged frog critical habitat. These criteria, which follow the recovery strategy outlined in the final Recovery Plan (Service 2002), focused on designating units (1) Throughout the geographic and elevational range of the subspecies; (2) that would result in protecting populations that are geographically distributed in a manner that allows for the continued existence of viable and essential metapopulations despite fluctuations in the status of subpopulations; and (3) that possess large continuous blocks of occupied habitat, representing source populations and/or unique ecological characteristics, or areas where the reestablishment of California redlegged frogs is essential to the recovery of the subspecies (Service 2002). We first determined the occupancy status of areas. Areas were considered to possess extant populations if California redlegged frogs have been documented in that area since 1985. We then selected areas that
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are inhabited by populations (source populations) that are capable of maintaining their current population levels and capable of providing individuals to recruit into subpopulations found in adjacent areas. We also selected several areas that may lack source populations, but which have other unique ecological significance, with the goal of maintaining the full range of the genetic variability and evolutionary adaptation in the subspecies. These include areas on the periphery of the current range and elsewhere that represent the historic distribution of the subspecies, and areas that provide connectivity among source populations or between source populations and unoccupied extirpated areas. Of the approximate 1,674,582 ha (4,140,440 ac) that are proposed for designation as critical habitat for the California redlegged frog, an estimated 81,020 ha (200,212 ac) are considered unoccupied habitat (Units 5 and 31). All of this unoccupied habitat occurs on Federal lands, and was identified in the core areas essential for California redlegged frog recovery in our final Recovery Plan (Service 2002). Both unoccupied and occupied areas not included in this designation can still be targets for recovery actions, including reestablishing populations.

The critical habitat units were delineated by first creating data layers in a geographic information system (GIS) format of all of the core areas as proposed in the final Recovery Plan (Service 2002). We then used the California Watershed Map (CALWATER version 2.2), a coverage developed by California Department of Water Resources (DWR), to identify watersheds containing core areas and delineate their boundaries in a 1:24,000 format. CALWATER is a set of watershed boundaries meeting standardized delineation criteria, consisting of six levels of increasing specificity, with the primary purpose of assigning a single, unique code to a specific watershed polygon (e.g., a planning watershed). CALWATER delineates the boundaries of planning watersheds 1,200 to 4,000 ha (3,000 to 10,000 ac) in size. We used these planning watersheds as the minimum mapping unit to delineate critical habitat units because watersheds represent functional, hydrologic management units that allow for efficient evaluation of factors that affect the quality of aquatic habitat and, thus, are extremely relevant to amphibian populations. The use of planning watersheds also allowed us to delineate critical habitat that protects habitat quality, breeding and nonbreeding habitat, and dispersal habitat in a manner consistent with the overall goal of protecting and sustaining metapopulations.

We selected all of the planning watersheds that intersected areas of high California redlegged frog abundance, areas essential to maintain connectivity, and/or areas of unique ecological significance as identified by the core areas from the final Recovery Plan (Service 2002). In areas where planning watersheds were large and/or watersheds were significantly altered hydrologically, we used alternative structural, political, or topographic boundaries (e.g., roads, county boundaries, elevation contour lines) as critical habitat boundaries because in these areas the benefits of using planning watersheds were limited.

Using the planning watersheds as the minimum mapping unit of this critical habitat designation would not allow us to avoid towns, other developed areas, or other areas where the primary constituent elements are not found. To address this shortcoming, we overlayed the planning watersheds with a 100m Universal Transverse Mercator (UTM) North American Datum of 1983 (NAD 83) grid. Using information from recent digital aerial photography, we then removed NAD 83 grid cells that did not contain the primary constituent elements. Although the data available to us were not sufficiently detailed to definitively map the primary constituent elements by grid cell, this approach did allow us to remove significant urban and other developed areas, including some agricultural lands, from the final designation.

We could not depend solely on federally owned lands for critical habitat designation as these lands are limited in geographic location, size, and habitat quality within the current range of the California redlegged frog. In addition to the federally owned lands, we are designating critical habitat on nonFederal public lands and privately owned lands, including land owned by the California Department of Parks and Recreation, the California Department of Fish and Game, DWR, and the University of California, as well as regional and local park lands and water district lands. All nonFederal lands designated as critical habitat meet the definition of critical habitat under section 3 of the Act in that they are within the geographical area occupied by the subspecies, are essential to the conservation of the subspecies, and may require special management considerations or protection.

We are also proposing to designate areas that are not currently known to be occupied by the subspecies, but which are essential for its conservation. We included one area in Tuolumne County in the Sierra Nevada and one in the Tujunga watershed in Los Angeles County in the Peninsular Range of southern California. These areas, within the historic range of the subspecies with some occurrences documented as recently as the mid1980s, are strong candidate areas for re establishment due to preliminary positive discussions with Federal agencies and adjacent landowners, are composed entirely of large blocks of Federal land, and are identified in the final Recovery Plan (Service 2002) as important reestablishment areas essential to the recovery of the California redlegged frog. These areas also provide important connectivity among currently occupied areas. In order for future reestablishment to be successful, special management in these areas is needed, including habitat restoration and the removal of nonnative species, such as predators. However, the primary constituent elements for California redlegged frogs are present in these areas.

Without reestablishment in the Sierra Nevada and Southern California, it is probable that California redlegged frogs will be extirpated from these areas, greatly reducing the likelihood of eventual recovery of the species. As a result, we have determined that reestablishment of California redlegged frog populations in these currently unoccupied areas is essential to the conservation of the species. Since the listing of California redlegged frogs as a threatened species in 1996, no progress has been made improving habitat for this species within these unoccupied areas. Because California red legged frogs have been extirpated from these areas, Federal agencies have determined their actions will not adversely affect California red legged frogs and have further declined to use their authority under section 7(a)(1) to help recover the California redlegged frogs in the Sierra Nevada and southern Transverse and Peninsular Ranges. Therefore, given the lack of protection for these areas, it is important to ensure that special management actions are implemented in unoccupied lands within the Sierra Nevada by designating them as critical habitat. Special Management Considerations or Protections

As we undertake the process of designating critical habitat for a species, we first evaluate lands defined by those physical and biological features
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essential to the conservation of the species for inclusion in the designation pursuant to section 3(5)(A) of the Act. Secondly, we then evaluate lands defined by those features to assess whether they may require special management considerations or protections. As discussed throughout this proposed rule, our previous final designation of critical habitat for the California redlegged frog (66 FR 14626, March 13, 2001) and in our final recovery plan for the species (Service 2002), the frog and its habitat are threatened by a multitude of factors including by not limited to: degradation and loss of habitat through urbanization, mining, improper management of grazing, recreation, invasion of nonnative plants, impoundments, water diversions, degraded water quality, and introduced predators, and previous overexploitation. While many of these threats operate concurrently and cumulatively with each other and with natural disturbances (e.g., droughts and floods), the fragmentation of existing habitat, and the continued colonization of existing habitat by nonnative species, may represent the most significant current threats to California redlegged frogs. As such we believe that each area proposed for designation as critical habitat may require some level of management and/or protection to address the current and future threats to the California redlegged frog and habitat essential to its conservation to ensure the overall recovery of the subspecies. Relationship to Section 4(a)(3) of the Act

The Sikes Act Improvements Act of 1997 (Sikes Act) requires each military installation that includes land and water suitable for the conservation and management of natural resources to complete, by November 17, 2001, an Integrated Natural Resources Management Plan (INRMP). An INRMP integrates implementation of the military missio

FOR FURTHER INFORMATION CONTACT For general information, and for information about Alameda, Butte, Contra Costa, El Dorado, Fresno, Kern, Marin, Mariposa, Merced, Napa, Plumas, San Joaquin, San Mateo, Santa Clara, Solano, Sonoma, Stanislaus, Tehama, and Tuolumne Counties, contact Wayne White, Field Supervisor, Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2800 Cottage Way, Suite W. 2605, Sacramento, California 95825 (telephone 916/4146600; facsimile 916/4146712).

For information about Monterey, Los Angeles, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz, and Ventura Counties, contact Diane Noda, Field Supervisor, Ventura Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2394 Portola Road, Suite B, Ventura, California 93003 (telephone 805/6441766; facsimile 805/6443958).

For information about areas in the San Gabriel Mountains of Los Angeles County or Riverside and San Diego Counties, contact Jim Bartel, Field Supervisor, Carlsbad Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2730 Loker Avenue West, Carlsbad, California 92008 (telephone 760/4319440; facsimile 760/4319624).