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CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AF68

NOTICE: Part II

DOCUMENT ACTION: Proposed rule.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the California Tiger Salamander, Central Population

DATES: We will accept comments from all interested parties until October 12, 2004. We must receive requests for public hearings, in writing, at the address shown in the ADDRESSES section by September 24, 2004.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to designate critical habitat for the California tiger salamander (Ambystoma californiense) (referred to hereafter as the CTS) pursuant to the Endangered Species Act of 1973, as amended (Act). This rule contains the proposal for the Central California population of the CTS (hereafter referred to as the Central population). Approximately 382,666 acres (ac) (154,860 hectares (ha)) occur within the boundaries of the proposal for the Central population.

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL INFORMATION

The proposed critical habitat is in the following 20 counties in central California: Alameda, Amador, Calaveras, Contra Costa, Fresno, Kern, Kings, Madera, Mariposa, Merced, Monterey, Sacramento, San Benito, San Joaquin, San Luis Obispo, Santa Clara, Solano, Stanislaus, Tulare, and Yolo. This proposed designation does not include critical habitat for the Santa Barbara County or Sonoma County areas. A proposed rule to designate critical habitat for the Santa Barbara County population was published on January 22, 2004 (69 FR 3064). We are not proposing to designate critical habitat for the Sonoma County geographic area of the California tiger salamander at this time. We are currently in the process of developing a management strategy for the Sonoma County area for the California tiger salamander and other listed and sensitive species. The planning efforts include various local, State and Federal agencies including ourselves, the U.S. Army Corps of Engineers, the California Department of Fish and Game, the County of Sonoma, the cities of Santa Rosa, Rohnert Park, and Cotati, and local and regional environmental organizations. The group is developing a management and restoration plan as well as identifying areas for conservation of the vernal pool and other California tiger salamander habitat within the area.

We expect the plan, when complete, to provide a better means of identifying essential habitat than our critical habitat designation process can provide at the present time. By bringing together all local, State, and Federal species experts and local planning officials we are better able to identify areas which are essential for the conservation of the California tiger salamander in Sonoma County. The management planning process is a collaborative effort involving cooperation and input from numerous stakeholders such as landowners, public land managers, and the general public. This allows the best information and local knowledge to be brought to the table, and may encourage a sense of commitment to the California tiger salamander's continued well being in the area. Due to time constraints we are unable to match this level of public participation in the critical habitat designation process. We believe that currently designating proposed critical habitat would cause more harm to the species by causing delays to and confusing the current ongoing process. The enhancement and management of California tiger salamander habitat will benefit greatly from coordination between the various land owners and managers in the area. The ongoing planning process can provide for that coordination, whereas the critical habitat designation process may not. Once the planning efforts have identified areas essential for the California tiger salamander, we will consider proposing critical habitat at that time. Should these planning efforts fail to identify essential areas for the California tiger salamander we will issue a notice to propose additional critical habitat for the species.

Critical habitat identifies specific areas, both occupied and unoccupied by a listed species, which are essential to the conservation of the species and that may require special management considerations or protection. The primary constituent elements for the California tiger salamander are aquatic and upland areas, including vernal pool complexes, where suitable breeding and nonbreeding habitats are interspersed throughout the landscape, and are interconnected by continuous dispersal habitat. All areas proposed for designation as critical habitat for the Central population contain one or more of the primary constituent elements.

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Section 4 of the Act requires us to consider economic and other relevant impacts of specifying any particular area as critical habitat. Section 7 of the Act prohibits destruction or adverse modification of critical habitat by any activity funded, authorized, or carried out by any Federal agency. We solicit data and comments from the public on all aspects of this proposal, including data on the economic and other impacts of designation. We may revise this proposal to incorporate or address new information received during the comment period. Public Comments Solicited

We intend that any final action resulting from this proposal will be as accurate and as effective as possible. Therefore, comments or suggestions from the public, other concerned governmental agencies, the scientific community, industry, or any other interested parties concerning this proposed rule are hereby solicited. Comments particularly are sought concerning:
(1) The reasons why any habitat should or should not be determined to be critical habitat as provided by section 4 of the Act, including whether the benefit of designation will outweigh any threats to the species due to designation;
(2) Specific information on the amount and distribution of California tiger salamander habitat, and what habitat is essential to the conservation of the species and why;
(3) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat; (4) Any foreseeable economic or other potential impacts resulting from the proposed designation and, in particular, any impacts on small entities;
(5) 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;
(6) Specific information from present landowners regarding the current extent and quality of extant occurrences and breeding habitats found within the proposed designated geographic areas and units; (7) Whether or not private landowners are willing to enter into partnerships or conservation agreements with us for the benefit of the California tiger salamander and its habitats;
(8) Whether or not we should enter into conservation agreements or partnerships with private landowners for the conservation of the California tiger salamander and its habitats and, upon successful implementation of these agreements, if we should remove these areas from critical habitat; and
(9) Appropriateness of excluding any proposed areas, such as portions of the former Fort Ord for which an HCP is currently being developed.

If you wish to comment, you may submit your comments and materials concerning this proposal by any one of several methods (see ADDRESSES section). Our practice is to make comments, including names and home addresses of respondents, available for public review during regular business hours. 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 (see ADDRESSES section).
Designation of Critical Habitat Provides Little Additional Protection to the 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 available conservation resources. The Service's present system for designating critical habitat has evolved since its original statutory prescription into a process that provides little real conservation benefit, is driven by litigation and the courts 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 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 species or 36 percent of the 1,244 listed species in the U.S. under the jurisdiction of the Service have designated critical habitat. We address the habitat needs of all 1,244 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 for our failure to designate critical habitat, 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, to respond to Notices of Intent (NOIs) to sue relative to critical habitat, and to comply with the growing number of adverse court orders. As a result of this consequence, listing petition responses, the Service's own proposals to list critically imperiled species, and final listing determinations on existing proposals are all significantly delayed.

The accelerated schedules of court ordered designations have left the Service with almost little ability to provide for adequate public [[Page 48572]]
participation or to ensure a defectfree rulemaking process before making decisions on listing and critical habitat proposals due to the risks associated with noncompliance with judiciallyimposed deadlines. This situation in turn fosters a second round of litigation in which those who fear adverse impacts from critical habitat designations challenge those designations. The cycle of litigation appears endless, is very expensive, and in the final analysis provides relatively little additional protection to listed species.

The costs resulting from the designation include legal costs, the costs of preparation and publication of the designation, the analysis of the economic effects and the costs of requesting and responding to public comments, and, in some cases, the costs of compliance with National Environmental Policy Act, represent the costs of critical habitat designation. None of these costs result in any benefit to the species that is not already afforded by the protections of the Act enumerated earlier, and theses associated costs directly reduce the scarce funds available for direct and tangible conservation actions. Background

A physical description of the CTS, and other information about its taxonomy, distribution, life history, and biology is included in the Background section of the final rule to list California tiger salamander as a threatened species, published in the Federal Register earlier. Additional relevant information may be found in the final rules to list the Santa Barbara County DPS (65 FR 57242, September 21, 2000) and the Sonoma County DPS CTS (68 FR 13498, March 13, 2003), and the January 22, 2004, proposal to designate critical habitat for the Santa Barbara population (69 FR 3064).

Habitat Requirements and Characteristics

The CTS inhabits, in Central California, lowelevation (typically below 1,500 feet (ft) (460 m)), vernal pools, vernal pool complexes, and seasonal ponds in associated annual grasslands, oak savannah, and coastal scrub plant communities of the Bay Area (Santa Clara Valley), Central Coast, Central Valley, and Southern San Joaquin Valley (Shaffer et al. 1993; Service 2000; Service 2003).

CTS are found in seasonal ponds, natural vernal pools, vernal pool complexes, and small artificial water bodies such as stockponds for breeding during their aquatic phase (Stebbins 1985; Zeiner et al. 1988; Shaffer et al. 1993). However, stockponds often are not optimum aquatic breeding habitat for California tiger salamanders because stockponds may not hold water long enough for completion of part of their life cycle. Hydroperiods may be so short that larvae cannot metamorphose (e.g., early drawdown of irrigation ponds), or so long that predatory fish and bullfrogs (Rana catesbeiana) can colonize the pond (Shaffer et al. 1993; Seymour and Westphal 1994). Permanent wetlands can support breeding California tiger salamanders if fish are not present, but extirpation of the salamander occurrence is likely if fish are introduced (Shaffer et al. 1993; Seymour and Westphal 1994). Artificial ponds also require ongoing maintenance and are often temporary structures. Periodic maintenance to remove silt from stockponds or to reinforce or strengthen berms may also cause a temporary loss of functioning aquatic habitat. Regardless of vernal pool, pond, or seasonal wetland type, successful breeding ponds for California tiger salamanders need to be inundated (hold water) for a minimum of 12 weeks to allow for successful metamorphosis.

The aquatic component of the Central population habitat consists of temporary ponded freshwater habitats. Historically, the vernal pools and vernal pool complexes constituted the majority of California tiger salamander breeding habitat. Vernal pools typically form in topographic depressions underlain by an impervious layer (such as claypan, hardpan, or volcanic layer) that prevents downward percolation of water, and they occur as groups of pools referred to as vernal pool complexes. Vernal pool hydrology is characterized by ponding of water during the late fall, winter, and spring, followed by complete desiccation (drying out) during the summer dry season (Holland and Jain 1998).

California tiger salamanders spend the majority of their lives in upland habitats. The upland component of Central population habitat typically consists of vernal pool grassland or grassland savannah with scattered oak trees. However, some occupied California tiger salamander breeding ponds exist within mixed grassland and woodland habitats, in woodlands, scrub, or chaparral habitats.

Within these upland habitats, adult California tiger salamanders spend part of their lives in the underground burrows of small mammals, especially the burrows of California ground squirrels (Spermophilus beecheyi) and valley pocket gophers (Thomomys bottae) (Barry and Shaffer 1994), at depths ranging from 20 cm (8.0 in) to 1 m (3.3 ft) beneath the ground surface (Trenham 2001). These burrows provide food for California tiger salamanders, as well as protection from the sun and wind associated with the dry California climate that can cause desiccation of amphibian skin. Although California tiger salamanders are members of a family of burrowing salamanders, California tiger salamanders are not known to create their own burrows in the wild and require small mammal burrows for survival. Because they live underground in the burrows of mammals, they are rarely encountered even where abundant.

Dispersal and Migration

Movements made by California tiger salamanders can be grouped into two main categories: (1) Breeding migration, and (2) interpond dispersal. Breeding migration is the movement of salamanders to and from a pond from the surrounding upland habitat. After metamorphosis, juveniles move away from breeding ponds into the surrounding uplands, where they live continuously for several years (on average, 4 years). Upon reaching sexual maturity, most individuals return to their natal (birth) pond to breed, while 20 percent disperse to other ponds (Trenham et al. 2001). Following breeding, adult California tiger salamanders return to upland habitats, where they may live for one or more years before breeding again (Trenham et al. 2000).

Data suggest that juvenile California tiger salamanders disperse further into upland habitats than adult California tiger salamanders. A trapping study conducted in Solano County during winter 200203 found that juveniles used upland habitats further from breeding ponds than adults (Trenham and Shaffer, in review). More juvenile salamanders were captured at distances of 300, 600, and 1,300 ft (100, 200, and 400 m), respectively, from a breeding pond than at 160 ft (50 m). Large numbers (approximately 20 percent of total captures) were found 1,300 ft (400 m) from a breeding pond. Fitting a distribution curve to the data revealed that 95 percent of juvenile salamanders could be found within 2,000 ft (640 m) of the pond, with the remaining 5 percent being found at even greater distances.

Postbreeding movements away from breeding ponds by adults appear to be much smaller. During postbreeding emigration, radioequipped adult California tiger salamanders were tracked to burrows 62 to 813 ft (19 to 248 m) from their breeding ponds
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(Trenham 2001). These reduced movements may be due to adult California tiger salamanders having depleted physical reserves postbreeding, or also due to the drier weather conditions that are typical of the period when adults leave the ponds.

The spatial distribution of California tiger salamanders in the uplands surrounding aquatic habitats or breeding ponds is a key issue for protection of upland and breeding habitat and essential conservation planning. Although it might be supposed that California tiger salamanders will move only short distances if abundant burrows are found near their ponds, this is not the case. In the aforementioned study in Solano County, while abundant burrows are available near the pond, a nearly equal number of California tiger salamanders were captured at 300, 600, and 1,300 ft (100, 200 and 400 m), respectively, from the breeding pond (Trenham and Shaffer, in review). Similarly, Trenham (2001) tracked salamanders to burrows up to 800 ft (248 m) from a breeding pond, although burrows were abundant at distances nearer to the pond. In addition, rather than staying in a single burrow, most individuals used several successive burrows at increasing distances from the pond.

Documented dispersers had moved up to 2,200 ft (670 m), and, based on a projected exponential relationship between dispersal probability and distance, less than 1 percent of dispersers are likely to move between ponds separated by 0.70 mile (mi) (1,160 m) (Trenham et al. 2001). The frequency of dispersal among known extant occurrences or subpopulations will ultimately depend on the distance between the ponds or complexes and also on the intervening habitat (e.g., salamanders may move more quickly through grassland than through more densely vegetated scrublands).

Although the studies discussed above provide an approximation of the distances that California tiger salamanders regularly move from their breeding ponds, upland habitat features influence movements in a particular landscape. Unlike other ambystomatid salamanders, California tiger salamanders and other tiger salamanders are grassland animals and do not favor forested areas as corridors for movement or longterm residence. Trenham (2001) found that radiotracked adults favored grasslands with scattered large oaks over more densely wooded areas. Based on radiotracked adults, there is no indication that California tiger salamanders favor certain habitat types as corridors for terrestrial movements (Trenham 2001).

Previous Federal Actions

For a discussion of previous Federal actions regarding the Central population, please see the final rule to list the Central California Distinct Population Segment of the California tiger salamander as threatened across its range. Federal actions on the CTS prior to May 2004 are summarized in that final rule, published in a recent Federal Register, and are incorporated by reference.

Critical Habitat

Critical habitat is defined in section 3(5)(A) of the Act 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, preserve, or other conservation area. It does not allow government or public access to private lands. Critical habitat receives protection under section 7 of the Act through the prohibition against destruction or adverse modification of critical habitat with regard to actions carried out, funded, or authorized by a Federal agency. Section 7 requires consultation on Federal actions that may adversely affect critical habitat, and conferences on Federal actions that are likely to result in the destruction or adverse modification of critical habitat. In our regulations at 50 CFR 402.02, we define destruction or adverse modification as ``a direct or indirect alteration that appreciably diminishes the value of critical habitat for both the survival and recovery of a listed species. Such alterations include, but are not limited to, alterations adversely modifying any of those physical or biological features that were the basis for determining the habitat to be critical.'' Aside from the added protection that may be provided under section 7, the Act does not provide other forms of protection to lands designated as critical habitat. Because consultation under section 7 of the Act does not apply to activities on private or other nonfederal lands that do not involve a Federal nexus, critical habitat designation would not afford any additional protections under the Act against such activities.

To be included in a critical habitat designation, the habitat must first be ``essential to the conservation of the species.'' Critical habitat designations identify, to the extent known using the best scientific and commercial data available, habitat areas that provide essential physical and biological features (i.e., areas on which are found the 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 areas 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. 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 scientific and commercial data demonstrate that unoccupied areas are essential for the conservation needs of the species.

Within the geographic areas occupied by the species, we will designate only areas currently known to be essential. Essential areas should already have the features and habitat characteristics that are necessary to sustain the species. We will not speculate about what areas might be found to be essential if better information became available, or what areas may become essential over time. If the information available at the time of designation does not show that an area is essential to the conservation of a species, then the area should not be included in the critical habitat designation. We will not designate areas
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that do not now have the primary constituent elements, as defined at 50 CFR 424.12(b). We have excluded from this proposal some areas where CTS are currently found, areas of suitable habitat where they might potentially occur, some localities where they historically occurred, and areas that do not have one or more of the primary constituent elements. Only areas considered essential to the conservation of the species are included in this proposal.

Section 4(b)(2) of the Act requires that we take into consideration the economic impact, and any other relevant impact, including impacts to National security, 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), provides criteria, establishes procedures, and provides guidance to ensure that decisions made by the Service represent the best scientific and commercial data available. Our policy requires Service 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 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 peerreviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, unpublished materials, and expert opinion or personal knowledge.

We recognize that the proposed designation of critical habitat does not include all of the occupied habitat areas that may eventually be determined to be essential for the conservation of the species. For these reasons, everyone should understand that critical habitat designations do not signal that habitats outside the designation are unimportant to California tiger salamanders. Areas outside the critical habitat designation will continue to be subject to conservation actions that may be implemented under section 7(a)(1), and to the regulatory protections afforded by the section 7(a)(2) jeopardy standard and the section 9 take prohibition, as determined on the basis of the best available information at the time of the action. We specifically anticipate that federally funded or assisted 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 determining areas that are essential to conserve the Central population, we used the best scientific and commercial data available. We have reviewed the overall approach to the conservation of the California tiger salamander undertaken by local, State, and Federal agencies operating within the species' range since its proposed listing in 2003 (68 FR 28648). We have also reviewed available information that pertains to the upland and aquatic habitat requirements of this species. In our designation, we included only areas within which the best available information indicates the species currently occurs. We identified proposed critical habitat units that we thought had the highest likelihood to be selfsustaining on the basis of density of CTS occurrences, and kind, amount, and quality of habitat associated with those occurrences. The proposed units represent the range of environmental, ecological, and genetic variation of the CTS and contain the primary constituent elements we have determined are essential to the conservation of the species.

The extant occurrences within proposed units total approximately 68 percent of extant occurrences within the range of the species. These extant occurrences include observations from CNDDB (2003), data in reports submitted during section 7 consultations, data from biologists holding section 10(a)(1)(A) recovery permits; research published in peerreviewed articles and presented in academic theses and agency reports, and regional Geographic Information System (GIS) coverages.

The proposed critical habitat units were delineated by creating approximate areas for the units by screen digitizing polygons (map units) using ArcView (Environmental Systems Research Institute, Inc.), a computer GIS program. The polygons were created by overlaying extant California tiger salamander location points with 0.7 mile buffers (CNDDB 2003) (see Criteria section below), and mapped vernal pool grassland habitats (Holland 1998a, 2003), or other vernal pool or grassland location information, onto SPOT imagery (satellite aerial photography).

We evaluated the resulting shape files (delineating historic geographic range and potential suitable habitat), refined elevation and hydrologic ranges, and identified areas of nonessential habitat (i.e., not containing the primary constituent elements) (see Primary Constituent Elements section). We excluded areas that do not contain one or more of the primary constituent elements or were not found to be essential for the conservation of the species because: (1) The area is highly degraded and may not be restorable; (2) the area is small, highly fragmented, or isolated and may provide little or no longterm conservation value; and (3) other areas within the geographic region were determined to be sufficient to meet the conservation needs of the species.

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 propose as critical habitat, we are required to base critical habitat determinations on the best scientific and commercial data available and to consider those physical and biological features (primary constituent elements (PCEs)) 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, and rearing (or development) of offspring; and habitats that are protected from disturbance or are representative of the historic geographical and ecological distributions of a species.

All areas proposed as critical habitat for the Central population are within the species' historic range and contain one or more of the physical or biological features (primary constituent elements) identified as essential for the conservation of the species. Critical habitat for Central population includes essential aquatic habitat, essential upland nonbreeding habitat with underground refugia, dispersal habitat connecting occupied California tiger salamander locations to each other, and vernal pool complexes where integrated function of uplands and wetlands provide physical and biological features
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essential to the conservation of the species. In addition, the critical habitat we have proposed is designed to conserve the distinct genetic structure of the Central population and allow for an increase in the size of salamander populations, both of which are essential to the conservation of the species. Special management, such as habitat rehabilitation efforts (e.g., removal of nonnative predators, control of introduced tiger salamanders, and erosion and sediment control measures), may be necessary throughout the areas being proposed.

Based on our current knowledge of the life history, biology, and ecology of the species and the relationship of its essential life history functions to its habitat, as summarized above (see Background section), we have determined that the CTS requires the following primary constituent elements:
(1) Standing bodies of fresh water, including natural and manmade (e.g., stock) ponds, vernal pools, and other ephemeral or permanent water bodies that typically become inundated during winter rains and hold water for a sufficient length of time necessary for the species to complete the aquatic portion of its life cycle.
(2) Barrierfree upland habitats adjacent to breeding ponds that contain small mammal burrows, including but not limited to burrows created by the California ground squirrel and valley pocket gopher. Small mammals are essential in creating the underground habitat that adult California tiger salamanders depend upon for food, shelter, and protection from the elements and predation.
(3) Upland areas between occupied locations (PCE 1) and areas with small mammal burrows (PCE 2) that allow for dispersal among such sites. (4) The geographic, topographic, and edaphic features that support aggregations or systems of hydrologically interconnected pools, swales, and other ephemeral wetlands and depressions within a matrix of surrounding uplands, which together form hydrologically and ecologically functional units called vernal pool complexes. These features contribute to the filling and drying of the vernal pool, maintain suitable periods of pool inundation for larval salamanders and their food sources, and provide breeding, feeding, and sheltering habitat for juvenile and adult salamanders and small mammals that create burrow systems essential for CTS estivation.

We describe the relationship between each of these PCEs and the conservation of the salamander in more detail below.

The essential aquatic habitat described as the first PCE is essential for Central population breeding and for providing space, food, and cover necessary to sustain early life history stages of larval and juvenile CTS. Breeding habitat consists of fresh water bodies, including natural and manmade ponds (e.g., stockponds), and vernal pools. To be considered essential, aquatic and breeding habitats must have the capability to hold water for a minimum of 12 weeks in the winter or spring in a year of average rainfall because this is the amount of time needed for larvae to grow into metamorphosed juveniles so they can become capable of surviving in upland habitats. During periods of drought or lessthanaverage rainfall, these sites may not hold water long enough for individuals to complete metamorphosis, however, these sites would still be considered essential because they constitute breeding habitat in years of average rainfall. Without its essential aquatic and breeding habitats, the Central population would not survive, reproduce, develop juveniles, and grow into adult individual salamanders that can complete their life cycles.

Essential upland habitats containing underground refugia described as the second PCE are essential for the survival of adult and juvenile salamanders that have recently undergone metamorphosis. Adult and juvenile California tiger salamanders are primarily terrestrial. Adult California tiger salamanders enter aquatic habitats only for relatively short periods of time to breed. For the majority of their life cycle, California tiger salamanders depend for survival on upland habitats containing underground refugia in the form of small mammal burrows. California tiger salamanders cannot persist without upland underground refugia. These underground refugia provide protection from the hot, dry weather typical of California in the nonbreeding season. California tiger salamanders also find food in small mammal burrows and rely on the burrows for protection from predators. The presence of small burrowing mammal populations is essential for constructing and maintaining burrows. Without the continuing presence of small mammal burrows in upland habitats, California tiger salamanders would not be able to survive.

Essential dispersal habitats generally consist of upland areas adjacent to essential aquatic habitats which are not isolated from essential aquatic habitats by barriers that California tiger salamanders cannot cross. Essential dispersal habitats provide connectivity among CTS suitable aquatic and upland habitats. While CTS can bypass many obstacles, and do not require a particular type of habitat for dispersal, the habitats connecting essential aquatic and upland habitats need to be free of barriers (e.g., a physical or biological feature that prevents salamanders from dispersing beyond the feature) to function effectively. Examples of barriers are areas of steep topography devoid of soil or vegetation. Agricultural lands such as row crops, orchards, vineyards, and pastures do not constitute barriers to the dispersal of California tiger salamanders. In general, we propose critical habitat that allows for dispersal between extant occurrences within 0.7 mi (1.13 km) of each other. To provide for conservation of the species, we choose 0.7 mi because that distance provides for 99 percent of the chances that individual salamanders can move and breed between extant occurrences, and, thereby, provides for genetic exchange between individuals within each region.

The dispersal habitats described as the third PCE are essential for the conservation of the CTS. Protecting the ability of California tiger salamanders to move freely across the landscape in search of suitable aquatic and upland habitats is essential in maintaining gene flow and for recolonization of sites that may become temporarily extirpated. Lifetime reproductive success for the CTS and other tiger salamanders is naturally low. Trenham et al. (2000) found the average female bred 1.4 times and produced 8.5 young that survived to metamorphosis per reproductive effort. This reproduction resulted in roughly 11 metamorphic offspring over the lifetime of a female. In part, this low reproductive success is due to the extended time it takes for California tiger salamanders to reach sexual maturity; most do not breed until 4 or 5 years of age. While individuals may survive for more than 10 years, many breed only once. Combined with low survivorship of metamorphosed individuals (in some populations, fewer than 5 percent of marked juveniles survive to become breeding adults (Trenham et al. 2000)), reproductive output in most years is not sufficient to maintain populations. This trend suggests that the species requires occasional large breeding events to prevent extirpation (temporary or permanent loss of the species from a particular habitat) or extinction (Trenham et al. 2000). With such low recruitment, isolated populations are susceptible to unusual, randomly occurring natural events as well as from
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humancaused factors that reduce breeding success and individual survival. Factors that repeatedly lower breeding success in isolated vernal pools or ponds can quickly extirpate an occurrence of the species. Therefore, an essential element for successful conservation is the presence and maintenance of sets of interconnected sites that are within the ``rescue'' distance of other ponds (Trenham et al. 2001).

Dispersal habitats described as the third PCE are also essential in preserving the population structure of the CTS. The life history and ecology of the California tiger salamander make it likely that this species has a metapopulation structure (Hanski and Gilpin 1991). A metapopulation is a set of breeding sites within an area, where typical migration from one local occurrence or breeding site to other areas containing suitable habitat is possible, but not routine. Movement between areas containing suitable upland and aquatic habitats (i.e., dispersal) is restricted due to inhospitable conditions around and between areas of suitable habitats. Because many of the areas of suitable habitats may be small and support small numbers of salamanders, local extinction of these small units may be common. The persistence of a metapopulation depends on the combined dynamics of these local extinctions and the subsequent recolonization of these areas through dispersal (Hanski and Gilpin 1991; Hanski 1994).

Vernal pool complexes addressed in the fourth PCE provide a significant amount of the habitat for Central population remaining in the southern San Joaquin and Central Valley regions, but less so in the Bay Area and Coast Range regions because so much vernal pool habitat has been converted to other land uses. Vernal pools and other natural seasonal ponds are the primary historic breeding sites used by California tiger salamanders (Storer 1925; Feaver 1971; Zeiner et al. 1988; Trenham et al. 2000). Historically, the species occurs in 10 of the 17 California vernal pool regions defined by KeelerWolf et al. (1998), including northeastern Sacramento Valley, southeastern Sacramento Valley, Santa Rosa, SolanoColusa, Livermore, Central Coast, Carrizo, southern Sierra Foothills, Santa Barbara, and San Joaquin Valley. Only in historic times have manmade stock ponds joined or, in some areas, replaced vernal pools as breeding habitat. We have included vernal pool complexes as a PCE because they represent a landscape within which the integrated function of the wetland and upland components together may provide one or more of the first three PCEs plus other physical and biological features essential for the conservation of the Central population, including features that provide for the hydrologic function of essential breeding habitat (PCE 4), and habitat for small mammals that create essential refugia (PCE 4). Upland and wetland functions are highly integrated and interdependent in vernal pool complexes and, rather than trying to partition these functions among discrete PCEs, we included vernal pool complexes as their own PCE.

A landscape that supports a vernal pool complex is typically grassland with areas of obstructed drainage that form the pools. The pools may be fed or connected by low drainage pathways called ``swales.'' Swales are often themselves seasonal wetlands that remain saturated for much of the wet season, but may not be inundated long enough to develop strong vernal pool characteristics. Swales, due to their connection to adjacent pools, are considered part of the vernal pool complex. Some pools have a substantial watershed that contributes to their water inputs; others may fill almost entirely from rain falling directly into the pool (Hanes and Stromberg 1998). Although exceptions are not uncommon, the watershed generally contributes more to the filling of larger or deeper pools, especially playa pools. Even in pools filled primarily by direct precipitation, Hanes and Stromberg (1998) report that subsurface inflows from surrounding soils can help dampen water level fluctuations during late winter and early spring. This function is important for maintaining inundation in breeding pools long enough for CTS larvae to complete their aquatic life stage and metamorphose into adults.

Upland areas associated with vernal pools are also an important source of nutrients to vernal pool organisms (Wetzel 1975). Vernal pool habitats derive most of their nutrients from detritus (decaying matter) washed into pools from adjacent uplands, and these nutrients provide the foundation for a vernal pool aquatic community's food chain. The plants, invertebrate and vertebrate animals of vernal pools, and vernal pool landscapes in general are important providers of food and habitat for waterfowl, shorebirds, wading birds, toads, frogs, and salamanders (Proctor et al. 1967; Krapu 1974; Swanson 1974; Morin 1987; Simovich et al. 1991; Silveira 1996). The uplands of vernal pool complexes may also provide breeding, feeding, and sheltering habitat for small mammals that adult CTS depend upon for food, shelter, and protection from the elements and predation.

In summary, the primary constituent elements consist of four components. At a minimum, these elements will include suitable breeding locations and associated uplands or vernal pool complexes associated with breeding locations that are connected by barrierfree dispersal habitats.

Criteria Used To Identify Critical Habitat

In our determination of critical habitat for the Central population, we selected areas that possess the physical and biological features that are essential to the conservation of the species and that may require special management considerations or protection. We avoided designating single occurrences unless such areas were considered unique. We also avoided areas surrounded by development or intensive agriculture. Agricultural lands may have been included if they were directly adjacent to the locations we selected to include as essential, thereby substantially reducing upland refugia for California tiger salamanders occupying that area, or were essential for connectivity between known occurrences. We do not have access to data on the most current agricultural uses in many areas of the proposed critical habitat and therefore are uncertain if California tiger salamander upland habitat may or may not remain in some locations.

Throughout this designation, when selecting areas of critical habitat, we made an effort to avoid developed areas, such as housing developments, that are unlikely to contribute to the conservation of the Central population. However, we did not map critical habitat in sufficient detail to exclude all developed areas, or other lands unlikely to contain the primary constituent elements. Areas within the boundaries of the mapped units, such as buildings, roads, parking lots, railroads, airport runways and other paved areas, lawns, and other urban landscaped areas will not contain any of the primary constituent elements and thus do not constitute critical habitat. Federal actions limited to these areas would not trigger a section 7 consultation, unless they affect the species and/or the primary constituent elements in adjacent critical habitat.

After identifying the primary constituent elements, we used the constituent elements in combination with information on CTS locations, geographic distribution, genetics,
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vegetation, topography, geology, soils, distribution of CTS occurrences within and between vernal pool types, watersheds, current land uses, scientific information on the biology and ecology of the CTS, and conservation principles to identify essential habitat. As a result of this process, each of the proposed critical habitat units possesses a unique combination of occupied aquatic and upland habitat types, landscape features, surrounding land uses, vernal pool types, ponds, topography, and representation of geographical range, environmental variability, and genetic composition.

We determined that conserving the CTS over the longterm requires a fivepronged approach: (1) Maintaining the current genetic structure across the species range; (2) maintaining the current geographic, elevational, and ecological distribution; (3) protecting the hydrology and water quality of breeding pools and ponds; (4) retaining or providing for connectivity between breeding locations for genetic exchange and recolonization; and (5) protecting sufficient barrierfree upland habitat around each breeding location to allow for sufficient survival and recruitment to maintain a breeding population over the long term.

To identify areas which are essential to the conservation of the Central population in accordance with these criteria, we first identified areas within the range where we had documented records (e.g., museum voucher specimens, reports filed by biologists) indicating California tiger salamander presence (CNDDB 2003). We determined that essential habitat should represent the current genetic structure of the CTS. Genetic variation is important to fitness and adaptive change (Meffe and Carroll 1997). These authors state that losses of diversity can result in reduced evolutionary flexibility and declines in fitness, and that changes in the distribution of genetic diversity can destroy local adaptations and break up coadapted gene complexes. Accordingly, we divided the current range of the Central population into four regions: (1) Central Valley, (2) Southern San Joaquin Valley, (3) East Bay, and (4) Central Coast. We further determined that essential habitat should represent the current geographic and elevational range of the species, as well as the range of habitat and environmental variability or other unique situations within each of the four regions. Conservation of the range of habitat types in which a species occurs helps maintain local adaptations that are important for the longterm viability of a species (Fugate 1992, King 1996, Fugate 1998). A fundamental concept in conservation biology is that species that are protected across their ranges have lower chances of extinction (Soule and Simberloff 1986, Noss et al. 2002). To represent this environmental variation, we selected areas with the highest density of Central population locations, the highest proximity to other Central population occurrences, known association of the occurrence with aquatic breeding habitat such as vernal pools or stockponds, and the least amount of habitat disturbance within each of the four regions.

Finally, we also determined that essential habitat should be of sufficient size to provide enough suitable habitat to maintain ecological functions in both aquatic and terrestrial habitat and to allow for movement within and between breeding locations within each unit when possible. This would enable Central population from other locations to ``rescue'' sites which may have low numbers as a result of natural or human factors. To determine a general guideline for the amount of upland habitat necessary to support a population of adult CTS, we reviewed the primary literature regarding California tiger salamander upland habitat use, including Trenham (2000), Trenham et al. (2000 and 2001), and Trenham and Shaffer (in review).

Data indicate that California tiger salamanders do not remain primarily in burrows close to aquatic habitats and breeding ponds, but instead move some distance out into the surrounding upland landscapes. As described in the Background section, California tiger salamanders have been found up to 1.2 mi (2 km) from occupied occurrences. Two studies conducted in Monterey and Solano counties provide the best available data on upland movement distances. First, the markrecapture study of Trenham et al. (2001) showed that California tiger salamanders commonly moved between ponds separated by 2,200 ft (670 m), suggesting that movements of this magnitude are not rare. Second, the ongoing study at Olcott Lake (Solano County) has directly documented the presence of high densities of juvenile and adult California tiger salamanders at upland locations at least 1,300 ft (400 m) from this highquality breeding pond.

Recent trapping efforts captured large numbers (representing 16 percent of total captures) of juvenile salamanders at 2,300 ft (700 m). Trenham and Shaffer (in review) determined that conserving upland habitats within 2,200 ft (670 m) of breeding ponds would protect 95 percent of California tiger salamanders at their study location in Solano County. Protecting the needed upland habitat area with a radius of 2,200 ft (670 m) around a single pond that has a 13 ft (10 m) radius may yield a minimum area of 350 ac (140 ha). However, the size of any occurrence or breeding pond may increase the total amount of necessary aquatic and upland habitat space for survival of any known occurrence.

We used 0.7 mi (1.13 km) as a guide for mapping the amount of upland habitat around locations where Central population is present. However, although the studies discussed above provide an approximation of the distances that California tiger salamanders can move from their aquatic habitats, breeding ponds, and known occupied aquatic habitats in search of suitable upland refugia, we recognize that upland habitat features will influence California tiger salamander movements in a particular landscape. As a result, we made adjustments to the upland areas to include additional areas up to the watershed boundaries or to include habitat containing the PCEs. In some cases we reduced the areas to exclude nonhabitat areas (those not exhibiting the PCEs) from the designation.

Section 10(a)(1)(B) of the Act authorizes us to issue permits for the take of listed species incidental to otherwise lawful activities. An incidental take permit application must be supported by a habitat conservation plan (HCP) that identifies conservation measures that the permittee agrees to implement for the species to minimize and mitigate the impacts of the requested incidental take. We often exclude non federal public lands and private lands that are covered by an existing operative HCP and executed implementation agreement (IA) under section 10(a)(1)(B) of the Act from designated critical habitat because the benefits of exclusion outweigh the benefits of inclusion as discussed in section 4(b)(2) of the Act. In the case of the CTS, only the San Joaquin County MultiSpecies HCP is a legally operating HCP that has identified the California tiger salamander as a covered species.

We are aware of five HCPs under various stages of development; however, we are not proposing these draft HCPs for exclusion because we have not yet made an initial determination that they meet our issuance criteria, provide adequate conservation for the species, and are ready for public notice and comment.

In summary, we propose critical habitat throughout the current range of the CTS because we believe protection of the areas is essential to the conservation of the species, and these areas may require special management.
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We then mapped as critical habitat sufficient habitat to ensure the conservation of the CTS in accordance with the five elements of the conservation strategy described above.

Special Management Considerations or Protections

When designating critical habitat, we assess whether the areas determined to be essential for conservation may require special management considerations or protections. Areas in need of management include not only the immediate locations where the species may be present, but additional areas adjacent to these that can provide for normal population fluctuations that may occur in response to natural and unpredictable events. The Central population may depend upon habitat components beyond the immediate areas where individuals of the species occur, if these areas support the presence of small mammals or are essential in maintaining ecological processes such as hydrology, expansion of distribution, recolonization, and maintenance of natural predatorprey relationships. We believe that the areas proposed for critical habitat may require special management considerations or protections due to the threats outlined below:
(1) Activities that introduce or promote the occurrence of bullfrogs and fish can be significant threats to Central population breeding ponds.
(2) Activities that could disturb aquatic breeding habitats during the breeding season.
(3) Activities that impair the water quality of aquatic breeding habitat.
(4) Activities that would reduce small mammal populations to the point that there is insufficient underground Central population refugia used for foraging, protection from predators, and shelter from the elements.
(5) Activities that create barriers impassable for salamanders or road crossings that increase mortality in upland habitat between extant occurrences in breeding habitat.
(6) Activities on adjacent uplands that disrupt vernal pool complexes' ability to support CTS breeding function.
(7) Activities that introduce nonnative tiger salamanders in areas where CTS is threatened by hybridization.

Proposed Critical Habitat Designation

We are proposing critical habitat for the Central population throughout four geographic regions. The proposed critical habitat units described below constitute our best assessment at this time of the areas essential for the conservation of the Central population. The regions are: (1) Central Valley Region, (2) Southern San Joaquin Valley Region, (3) the East Bay Region, and (4) the Central Coast Region. The maps in this proposed rule present a pictorial representation of the four regions and are not accurate with regard to the dividing line between the Central Coast and Central Valley regions in Alameda County. The maps in the rule portion of this document begin with Map 7 and run consecutively because they follow Maps 16 in the proposed critical habitat rule for the Santa Barbara population of the California tiger salamander already published in the Federal Register (69 FR 3064, January 22, 2004). We will continue to refine these maps as we acquire more refined or smaller scale mapping information.
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We are proposing 47 units as critical habitat for the Central population. Federal lands within the San Francisco Bay National Wildlife Refuge, the San Luis National Wildlife Refuge Complex, and Fort Hunter Liggett are included in proposed critical habitat units. Additionally, we have proposed critical habitat on lands within East Bay Regional County Park. Although some Federal, State, or local government lands occur within the boundaries of proposed critical habitat, the majority of the areas proposed for critical habitat designation occur on privately owned land. The approximate area encompassed within each proposed critical habitat unit and associated land ownership are shown in Table 1.
Table 1.Approximate Sizes and Land Ownership of Proposed Critical Habitat Units by Geographic Region Federal lands State lands Other lands Total Geographic region/proposed unit
ac ha ac ha ac ha ac ha Central Valley Unit 1.......................................... 0 ........... 0 ........... 3,789 1,533 3,789 1,533 Unit 2.......................................... 0 ........... 7 3 5,937 2,403 5,944 2,406 Unit 3.......................................... 0 ........... 0 ........... 10,191 4,124 10,191 4.124 Unit 4.......................................... 0 ........... 0 ........... 9,603 3,886 9,603 3,886 Unit 5.......................................... 0 ........... 0 ........... 3,128 1,266 3,128 1,266 Unit 6.......................................... 0 ........... 0 ........... 32,443 13,129 32,443 13,129 Unit 7.......................................... 0 ........... 0 ........... 1,010 409 1,010 409 Unit 8.......................................... 17 7 0 ........... 6,053 2,450 6,070 2,457 Unit 9.......................................... 0 ........... 0 ........... 17,799 7,203 17,799 7,203 Unit 10......................................... 0 ........... 0 ........... 10,585 4,283 10,585 4,283 Unit 11......................................... 0 ........... 0 ........... 8,291 3,355 8,291 3,355 Unit 12......................................... 9,330 3,776 1,564 633 130 52 11,024 4,461 Unit 13......................................... 3,406 1,378 0 ........... 2,356 953 5,762 2,332 Unit 14......................................... 1,540 623 0 ........... 4,355 1,762 5,895 2,386 Unit 15......................................... 0 ........... 0 ........... 7,353 2,976 7,353 2,976 Unit 16......................................... 0 ........... 21 8 13,481 5,455 13,502 5,464 Unit 17......................................... 0 ........... 824 333 27,108 10,970 27,932 11,304 Unit 18......................................... 415 168 0 ........... 8,400 3,400 8,815 3,568

Area Total.................................. 14,708 5,952 2,416 978 172,013 69,611 189,137 76,541 Southern San Joaquin Valley Region Unit 1.......................................... 0 ........... 0 ........... 9,122 3,692 9,122 3,692 Unit 2.......................................... 0 ........... 0 ........... 10,193 4,125 10,193 4,125 Unit 3.......................................... 0 ........... 0 ........... 7,924 3,207 7,924 3,207 Unit 4.......................................... 0 ........... 415 168 0 ........... 415 168 Unit 5A......................................... 0 ........... 4,342 1,757 0 ........... 4,342 1,757

Unit 5B..................................... 0 ........... 629 255 0 ........... 629 255

Area Total.................................. 0 ........... 5,386 2,180 27,239 11,023 32,625 13,203 East Bay Regi

FOR FURTHER INFORMATION CONTACT For general information, and for information about Alameda, Amador, Calaveras, Contra Costa, Fresno, Kern, Kings, Madera, Mariposa, Merced, Sacramento, San Joaquin, Santa Clara, Solano, Stanislaus, Tulare, and Yolo Counties, contact Wayne White, Field Supervisor, SFWO, at the address given above (telephone 916/4146600; facsimile 916/4146712).

For information about Monterey, San Benito, and San Luis Obispo Counties, contact Diane Noda, Field Supervisor, Ventura Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2394 Portola Road, Suite B, Ventura, CA 93003 (telephone 805/6441766; facsimile 805/644 3958).