Endangered and Threatened Wildlife and Plants; Revised Proposed Designation of Critical Habitat for the California Red-Legged Frog (Rana aurora draytonii, 66906-67064 [05-21594]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 70, Number 212 (Thursday, November 3, 2005)]
[Proposed Rules]
[Pages 66906-67064]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-21594]



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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Revised Proposed 
Designation of Critical Habitat for the California Red-Legged Frog 
(Rana aurora draytonii); Proposed Rule

Federal Register / Vol. 70, No. 212 / Thursday, November 3, 2005 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN-1018-AJ16


Endangered and Threatened Wildlife and Plants; Revised Proposed 
Designation of Critical Habitat for the California Red-Legged Frog 
(Rana aurora draytonii)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; revised proposed designation of critical 
habitat, special rule, reopening of comment period, and notice of 
availability of the draft economic analysis.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce the 
reopening of a 90-day public comment period for the proposed rule to 
designate critical habitat for the California red-legged frog (Rana 
aurora draytonii), pursuant to the Endangered Species Act of 1973, as 
amended (Act), and a concurrent 90-day comment period for the draft 
economic analysis for this proposed rule. A previous proposed rule to 
designate critical habitat was published on April 13, 2004 (69 FR 
19620). We herein revise those critical habitat boundaries to better 
reflect lands containing essential features for the California red-
legged frog, and we now propose to designate approximately 737,912 
acres (ac) (298,622 hectares (ha)) of critical habitat in 23 California 
counties.
    Section 4 of the Act requires us to consider the economic and other 
relevant impacts of specifying any area as critical habitat. We hereby 
solicit data and comments from the public on all aspects of this 
proposal, including data on the economic and other impacts of the 
designation. We have conducted an analysis of the economic impacts of 
designating these areas as critical habitat and are announcing the 
availability of the draft economic analysis for public review.
    A special rule is also being proposed to exempt existing routine 
ranching activities from the prohibitions of the Act because these 
practices have neutral or beneficial effects on the California red-
legged frog. We solicit additional data and information that may assist 
us in making a final decision on this proposed action.

DATES: We will accept comments from all interested parties until 
February 1, 2006. We must receive requests for public hearings, in 
writing, at the address shown in the ADDRESSES section by December 19, 
2005.

ADDRESSES: If you wish to comment on this proposed rule and/or the 
draft economic analysis, you may submit your comments and materials by 
any one of several methods:
    1. You may submit written comments and information to the Field 
Supervisor, Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife 
Service, 2800 Cottage Way, Suite W. 2605, Sacramento, CA 95825.
    2. You may hand-deliver written comments and information to our 
Sacramento Fish and Wildlife Office, at the above address, or fax your 
comments to 916/414-6712.
    3. You may send your comments by electronic mail (e-mail) to 
fw1crlf@fws.gov. For directions on how to submit electronic filing of 
comments, see the ``Public Comments Solicited'' section below. In the 
event that our Internet connection is not functional, please submit 
comments by the alternate methods mentioned above.
    All comments and materials received, as well as supporting 
documentation used in preparation of this proposed rule, will be 
available for public inspection, by appointment, during normal business 
hours at the above address.

FOR FURTHER INFORMATION CONTACT: For general information, information 
on the special rule, and information about the proposed designation in 
Alameda, Butte, Calaveras, Contra Costa, El Dorado, Kern, Marin, 
Merced, Napa, Nevada, San Mateo, Santa Clara, Solano, Stanislaus, and 
Yuba counties, contact Wayne White, Field Supervisor, Sacramento Fish 
and Wildlife Office, U.S. Fish and Wildlife Service, 2800 Cottage Way, 
Suite W. 2605, Sacramento, CA 95825 (telephone 916/414-6600; facsimile 
916/414-6712).
    For information about the proposed designation in Los Angeles, 
Monterey, 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, CA 93003 (telephone 805/644-1766; facsimile 805/644-
3958).
    For information about the proposed designation in the San Gabriel 
Mountains of Los Angeles County or Riverside County, contact Jim 
Bartel, Field Supervisor, Carlsbad Fish and Wildlife Office, U.S. Fish 
and Wildlife Service, 2730 6010 Hidden Valley Road, Carlsbad, CA 92009 
(telephone 760/431-9440; facsimile 760/431-9624).

SUPPLEMENTARY 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 and its associated draft economic 
analysis. On the basis of public comment, during the development of the 
final rule we may find that areas proposed do not have the essential 
features, are appropriate for exclusion under section 4(b)(2), or are 
not appropriate for exclusion, in which case they would either 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 
subspecies resulting from the designation;
    (2) Specific information on the amount and distribution of 
California red-legged frog and its habitat, and which habitat or 
habitat components (i.e., physical and biological features) are 
essential to the conservation of this subspecies and why;
    (3) Whether the primary constituent elements for the California 
red-legged frog as defined in this proposal are biologically and 
scientifically accurate, specifically;
    (a) Whether the requirement for two or more suitable breeding sites 
within 0.7 mi (1.2 km) is a feature essential to the conservation of 
the subspecies;
    (b) Whether providing 200 ft (60 m) surrounding aquatic and wetland 
habitat for shelter, forage and predator avoidance is sufficient for 
conservation of the subspecies;
    (4) Land use designations and current or planned activities in or 
adjacent to the areas proposed and their possible impacts on proposed 
critical habitat;
    (5) Not all of the lands that may contribute to the conservation of 
the red-legged frog are being proposed as critical habitat. We 
specifically solicit comment as to whether any other areas should be 
included and why;
    (6) With specific reference to sections 4(a)(3) and 4(b)(2) of the 
Act, we request information from the Department of Defense (DOD) to 
assist the Secretary of the Interior in excluding critical habitat on 
lands administered by, or under the control of, the DOD based on the 
benefit of an Integrated Natural Resources Management Plan (INRMP) to 
the

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conservation of the subspecies; and information regarding impacts to 
national security associated with proposed designation of critical 
habitat; and
    (7) Whether the proposed critical habitat unit in southern 
California with older occurrence records, RIV-2 Arroyo Seco Creek, (see 
Proposed Critical Habitat designation below) contains features 
essential to the conservation of the subspecies, and should be 
designated as critical habitat;
    (8) Whether the currently existing unoccupied critical habitat 
units as identified in the previous Federal Register (69 FR 19620; 
April 13, 2004) (Unit 5) in Tuolumne and Mariposa Counties, and (Unit 
31) in Los Angeles County, should remain as critical habitat; and,
    (9) Additional information pertaining to the promulgation of a 
special rule for the California red-legged frog to exempt from take 
prohibitions under section 9 of the Act existing routine ranching 
practices located on private and Tribal lands.
    (10) Information on how many of the State and local environmental 
protection measures referenced in the draft economic analysis were 
adopted largely as a result of the listing of the California red-legged 
frog, and how many were either already in place or enacted for other 
reasons;
    (11) Whether the draft economic analysis identifies all State and 
local costs attributable to the proposed critical habitat designation, 
and information on any costs that have been inadvertently overlooked;
    (12) Whether the draft economic analysis makes appropriate 
assumptions regarding current practices and likely regulatory changes 
imposed as a result of the designation of critical habitat;
    (13) Whether the draft economic analysis correctly assesses the 
effect on regional costs associated with land use controls that derive 
from the designation of critical habitat;
    (14) The economic analysis indicated potentially disproportionate 
impacts to areas within San Luis Obispo, Alameda, Contra Costa, Santa 
Barbara, and San Mateo Counties. Based on this information, we are 
considering excluding portions of these areas from the final 
designation per our discretion under section 4(b)(2) of the Act. We are 
specifically seeking comment along with additional information 
concerning our final determination for these five areas along with any 
other areas with potentially disproportionate impacts.
    (15) Whether the economic analysis appropriately identifies all 
costs that could result from the designation, in particular, any 
impacts on small entities or families; and whether it is appropriate 
that the analysis does not include the cost of project modifications 
that are the result of informal consultation only;
    (16) Whether there is information about alternate areas that could 
be used as substitutes for the economic activities planned in areas 
proposed as critical habitat that would offset the costs and allow for 
the conservation of critical habitat areas; and
    (17) 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 on this proposed rule and/or the draft 
economic analysis, you may submit your comments and materials 
concerning this proposal and its associated draft economic analysis 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 
1018-AJ16'' in your e-mail 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 916/414-6600. Please note that the e-
mail address fw1crlf@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.
    Copies of the proposed rule, draft economic analysis, and 
information regarding this proposed critical habitat designation are 
available on the Internet at https://www.fws.gov/pacific/sacramento.

Designation of Critical Habitat Provides Little Additional Protection 
to Species

    In 30 years of implementing the Act, (16 U.S.C. 1531 et seq.), we 
have found that the designation of statutory critical habitat provides 
little additional protection to most listed species, while consuming 
significant amounts of available conservation resources. Our 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). We believe 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 470 species or 37 percent 
of the 1,264 listed species in the U.S. under our jurisdiction have 
designated critical habitat.
    We address the habitat needs of all 1,264 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. We believe that it is 
these measures that may make the difference between extinction and 
survival for many species.
    We note, however, that the August 6, 2004, Ninth Circuit judicial 
opinion,

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Gifford Pinchot Task Force v. United State Fish and Wildlife Service) 
found our definition of adverse modification was invalid. In response 
to the decision, the Director has provided guidance to the Service 
based on the statutory language.

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 us to an ever-increasing series of court orders and court-
approved settlement agreements, compliance with which now consumes 
nearly the entire listing program budget. This leaves us 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, 
listing petition responses, our 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 
us with almost no ability to provide for adequate public participation 
or to ensure a defect-free rulemaking process 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 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 
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 the 
National Environmental Policy Act (NEPA). 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 they directly reduce the 
funds available for direct and tangible conservation actions.

Background

    This rule focuses on the reanalysis and re-proposal of critical 
habitat for the California red-legged frog (Rana aurora draytonii). For 
that reason, much of the information contained in previously published 
rules has not been included within this notice. For additional 
information on the biology and habitat requirements of the California 
red-legged frog, please refer to the following published rules: (59 FR 
4888; 61 FR 25813; 65 FR 54891; 66 FR 14626; 69 FR 19619).

Subspecies Description

    The California red-legged frog is the largest native frog in the 
western United States. It is endemic (native and restricted) to 
California and Baja California, Mexico, at elevations ranging from sea 
level to approximately 5,000 feet (ft) (1,500 meters (m)). The 
California red-legged frog gains its name from the typically red or 
pink color of its posterior abdomen and hind legs. The California red-
legged frog is one of two subspecies of the red-legged frog (Rana 
aurora). For a detailed description of the subspecies, see the Recovery 
Plan for the California Red-legged Frog (Service 2002) and references 
identified within the plan as well as information in previous Federal 
Register notices (69 FR 19620; 66 FR 14626; 61 FR 25813).

Life History

    During breeding season, which typically runs from November through 
April, males call to females from the margins of ponds and slow streams 
(Jennings et al., in litt. 1992). Actual mating most commonly occurs in 
March, but can vary depending on seasonal climatic patterns. Mating 
pairs enter a breeding position called amplexus, during which the 
female lays a jellylike mass of 2,000 to 5,000 reddish brown eggs in 
the water attached to some brace such as emergent vegetation. The eggs 
are immediately fertilized by the male, and hatch in 6 to 14 days 
depending on water temperatures (Jennings 1988). The resulting 
tadpoles, which likely feed on algae (Dickman, 1968 ), metamorphose 
into adult California red-legged frogs from July to September (Storer 
1925; Wright and Wright 1949; N. Scott, in litt. 1998), although some 
tadpoles have been observed to delay metamorphosis until the following 
March or April (Bobzien et al. 2000; Fellers et al. 2001; R. Smith, in 
litt. 2004). Adults tend to be nocturnal, while juveniles can be active 
at any time of day (Hayes and Tennant 1985).

Geographic Range

    The historic range of the California red-legged frog extended from 
Marin County, California, south along the coast to northwestern Baja 
California, Mexico, and inland as far as the vicinity of Redding in 
Shasta County, California (Jennings and Hayes 1985; Hayes and Krempels 
1986). Recent genetic studies have identified that the subspecies may 
extend north along the coast into Mendocino County, California (Shaffer 
et al. 2004). The range of the California red-legged frog has declined 
since being described by Storer (1925). Through comparison of 
historical museum records (1890-1980) and field surveys (1990-1992), 
Fisher and Shaffer (1996) present evidence of the extirpation (local 
extermination) of California red-legged frogs from 24 of 28 counties in 
a limited portion of its historical range. In 1996 when the subspecies 
was listed, 243 streams or drainages in 22 California counties were 
documented to contain populations of California red-legged frogs 
(California Natural Diversity Database (CNDDB) 2004). At the time of 
listing, California red-legged frogs were believed to have been 
extirpated from most of the southern Coastal Mountains from Santa 
Barbara south to Baja California and east along the Transverse (San 
Gabriel, San Bernadino, Santa Ynez, and Santa Monica Mountains) and 
Peninsular Ranges (San Jacinto, Santa Rosa, Agua Tibia, Laguna, Santa 
Ana Mountains). Since listing, two additional occurrences have been 
discovered south of the Tehachapi Mountains (CNDDB 2005) but may no 
longer be extant. Four additional occurrences have been recorded in the 
Sierra Nevada foothills, bringing the total to five known populations, 
compared to approximately 26 historical records (Berkeley Museum of 
Vertebrate Zoology 2004; CNDDB 2004; California Academy of Sciences 
2004; Barry in litt. 2005). Currently California red-legged frogs are 
only known from 3 disjunct regions in 26 California counties and is 
still present in Baja California, Mexico (Grismer 2002; Fidenci 2004; 
R. Smith and D. Krofta, in litt. 2005).

Threats

    For information regarding threats to the subspecies, refer to the 
previous final listing of the subspecies as well as the previous 
critical habitat proposal (61 FR 25813; 69 FR 19620). Our understanding 
of the threats of livestock grazing and stock pond development

[[Page 66909]]

described in the previous final listing of the subspecies has changed.
    Stock pond and small reservoir impoundments can provide suitable 
breeding habitat for the California red-legged frog. In many areas the 
presence of California red-legged frogs is due solely to these small 
ponded habitats. For example, at the Point Reyes National Seashore in 
Marin County, an area where there are more than 120 breeding sites with 
an estimated total adult population of several thousand California red-
legged frogs, the majority of the breeding sites are artificial 
stockponds constructed on lands that have been grazed by cattle for 
over 150 years (Fellers and Guscio 2004). In the Eastbay Regional Park 
District lands in Contra Costa and Alameda Counties, 43 of 179 ponds 
surveyed which were exposed to grazing, and were characterized with and 
without emergent vegetation, supported successful breeding frog 
populations often exhibiting high rates of annual breeding (Bobzien et 
al. 2000). For more information concerning the importance of stock 
ponds to the subspecies see the Special Rule section below.
    The Service now recognizes that managed livestock grazing at low to 
moderate levels has a neutral or beneficial effect on California red-
legged frog habitat (Bobzien et al. 2000) by keeping a mix of open 
water habitat and emergent vegetation which is beneficial to the 
subspecies. In some cases, without managed grazing, stock ponds would 
quickly fill with emergent vegetation resulting in habitat loss 
(Bobzien pers. comm. 2005).
    However, numerous studies, summarized by Kauffman and Krueger 
(1984) and Belsky et al. (1999), have shown that unmanaged livestock 
grazing (overgrazing) can negatively affect riparian and instream 
aquatic habitat. Some of the effects of unmanaged grazing include: 
Higher instream water temperatures resulting from reduction or removal 
vegetation, channel down cutting, lowered water tables and loss of 
plunge pools which results in direct loss of pool habitats for the 
California red-legged frog (Patla and Keinath 2005), as well as 
diminished water quality through increased sediment loads and nutrient 
levels (Belsky et al. 1999).

Habitat

    California red-legged frogs live in a Mediterranean climate, which 
is characterized by temporal and spatial changes in habitat quality. 
During a period of abundant rainfall, almost the entire landscape, 
including breeding ponds and streams may become suitable habitat for 
the adults. Conversely, habitat use may be drastically confined during 
periods of prolonged drought. Due to this variability, population sizes 
can vary widely from year to year. During favorable years, California 
red-legged frogs can produce large numbers of dispersing young, 
resulting in an increase in the number of occupied sites. In contrast, 
California red-legged frogs may temporarily disappear from an area 
during periods of extended drought. Therefore, it is essential to 
provide for sites that can be recolonized by dispersing individuals 
(Semlitsch 2000).
    The habitats used by this subspecies typically change in extent and 
suitability in response to the dynamic nature of floodplain and fluvial 
processes (i.e., natural water flow and sedimentation regimes that, in 
flux, create, modify, and eliminate deep pools, backwater areas, ponds, 
marshes, and other aquatic habitats). Rangewide, and even within local 
populations, the California red-legged frog uses a variety of areas, 
including various aquatic, riparian, and upland habitats. In some 
cases, they may complete their entire life cycle in a particular 
habitat (i.e., a pond is suitable for all life stages), and in other 
cases, they may seek multiple habitat types depending on climatic 
conditions or distance between and availability of wetland and hydric 
environments.
    Despite the California red-legged frog's ability to utilize 
multiple habitat types, there are certain habitat features they 
require. Most important is a breeding pond or slow flowing stream reach 
or plunge pool within a stream with some type of vegetative or other 
material to attach their egg masses, that holds water long enough for 
tadpoles to complete their metamorphoses and juveniles able to survive 
outside of water. California red-legged frogs often disperse from their 
breeding habitat to utilize various aquatic, riparian, and upland 
summer habitats during their migrations from one area to another. 
However, it is also common for individuals to remain in the breeding 
area on a year-round basis.
    Aquatic breeding habitat must remain hydrated until at least July, 
and preferably September, so the tadpoles can complete their 
metamorphoses. Drydowns after that time can be beneficial because they 
help prevent the establishment of predatory fish or bullfrogs (Hayes 
and Jennings 1989; Cook 1997; N. Scott, in litt. 1998). Water quality 
requirements for eggs and tadpoles include low salinity (below 4.5 
parts per thousand (ppt) for eggs, up to 7.0 ppt for tadpoles) 
(Jennings and Hayes 1990; M. Jennings, in litt. 1994), and temperatures 
below about 73[deg] Fahrenheit (23[deg] Celsius) (Cook 1997; Nussbaum 
et al. 1983). Water bodies free of bullfrogs and nonnative predatory 
fish, are optimal but California red-legged frog populations can 
persist in the presence of one or the other of these predators 
(Kiesecker and Blaustein 1998; Lawler et al. 1999).
    In Northern California, few California red-legged frog populations 
occupy naturally occurring wetland environments. Historically, 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. Our understanding of the 
role of stock ponds in the conservation of the California red-legged 
frog has evolved since listing. Without these stock ponds, the range of 
the California red-legged frog would be limited further in this region.

Dispersal

    Adult California red-legged frogs may disperse from breeding sites 
at any time of year. Dispersing adult California red-legged frogs in 
northern Santa Cruz County traveled distances from 0.25 miles (mi) (0.4 
kilometers (km)) to more than 2.0 mi (3.2 km) without apparent regard 
to topography, vegetation type, or riparian corridors (Bulger et al. 
2003). California red-legged frogs have also been radio tracked in East 
Las Virgenes Creek, Ventura County which has a Mediterranean climate 
characterized by highly variable rainfall (R. Smith, in litt. 2005). 
Habitat includes a well-defined creek and riparian zone with permanent 
deep pools. In contrast to California red-legged frog movements in 
Santa Cruz County, Smith et al. have found movements of California red-
legged frogs to be substantially less, with typical movements of 9--16 
feet (3--5 meters) from the water's edge. Maximum distance moved was 48 
feet (15 meters) (R. Smith, in litt. 2005). 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 1997; M. Jennings, in litt. 2000). Bobzien et 
al. (2000) observed juveniles inhabiting a wide variety of habitats 
while adults primarily inhabited deep pools. They postulated that 
juveniles might segregate themselves away from adults to escape 
predation and competition.
    For reasons that are currently unclear, juveniles tend to disperse 
away from

[[Page 66910]]

aquatic habitat occupied by adults. Juvenile dispersal is essential for 
recolonizing temporarily extirpated habitat and preventing genetic 
isolation because juveniles disperse in more directions, and for longer 
distances than do migrating adults (Wright, in litt. 1999; Bulger et 
al. 2003). Dispersal habitat for juveniles can be almost anything that 
provides sheltering vegetation or scattered wetlands or streams. This 
includes forested areas, nonnative grasslands, and even croplands, but 
is not known to include urbanized or suburban areas, suburban 
developments, or areas separated from breeding habitat by impassible 
barriers. Impassible barriers include wide or fast flowing rivers and 
streams, lakes greater than 50 ac (20 ha), and heavily traveled roads 
without underpasses or culverts (Reh and Seitz 1990; Fahrig et al. 
1995). Juveniles dispersing along riparian corridors may have higher 
survivorship, as sheltering vegetation and suitable aquatic habitat are 
both more common in such corridors (M. Jennings, in litt. 2000). 
Juveniles appear to have less strict requirements for aquatic habitat 
than adults, and tend to segregate away from adults in water bodies 
that are shallower or faster moving than those typically used for 
breeding (Hayes and Jennings 1989; Bobzien pers. comm. 2000; M. 
Jennings, in litt. 2000).
    The long-term probability of the survival and recovery of 
California red-legged frogs is dependent upon the protection of 
existing breeding habitat and associated uplands (Fellers and Kleeman 
2005), 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 
suitable breeding and non-breeding aquatic habitat, and fragmentation 
of interconnecting habitat (Vos and Chardon 1998).

Previous Federal Action

    On June 8, 2001, various homebuilding and commerce organizations 
filed a lawsuit in the U.S. District Court for the District of Columbia 
challenging our designation of critical habitat for the California red-
legged 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 a new economic analysis. The consent decree vacated 
the critical habitat designation for the California red-legged frog 
with the exception of Units 5 and 31, which were not known to be 
occupied by the California red-legged frog, and ordered us to 
promulgate a proposed revised designation by March 2004, and a final 
revised rule by November 2005. We published a revised critical habitat 
proposal on April 13, 2004 (69 FR 19620), which proposed the re-
designation of the previously established units. Due to comments 
received, our own re-evaluation of our selection criteria and the 
primary constituent elements required by the California red-legged frog 
(see below), we now issue this revised proposed critical habitat 
designation and its associated draft economic analysis.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as--(i) the 
specific areas within the geographical area occupied by the species, at 
the time it is listed in accordance with the provisions of section 4 of 
this 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 geographical area occupied by the species at the time 
it is listed in accordance with the provisions of section 4 of this 
Act, upon a determination by the Secretary that such areas are 
essential for the conservation of the species.
    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 result in the destruction or adverse 
modification of critical habitat. The designation of critical habitat 
does not affect land ownership or establish a refuge, wilderness, 
reserve, preserve, or other conservation area. Such designation does 
not allow government or public access to private lands.
    To be included in a critical habitat designation, the habitat 
within the geographical area occupied by the species must first have 
features that are ``essential to the conservation of the species.'' 
Critical habitat designations identify, to the extent known using the 
best scientific data available, habitat areas that provide essential 
life cycle needs of the species (i.e., areas on which are found the 
primary constituent elements, as defined at 50 CFR 424.12(b)).
    Specific areas within the geographical area occupied by the species 
at the time of listing may be included in critical habitat only if the 
essential features thereon may require special management or 
protection. Thus, we do not include areas where existing management is 
sufficient to conserve the species. (As discussed below, such areas may 
also be excluded from critical habitat pursuant to section 4(b)(2) of 
the Act.) Accordingly, when the best available scientific data do not 
demonstrate that the conservation needs of the species so require, we 
will not designate critical habitat in areas outside the geographic 
area occupied by the species at the time of listing. An area currently 
occupied by the species, but was not known to be occupied at the time 
of listing, will likely be essential to the conservation of the species 
and, therefore, included in the critical habitat designation.
    Our Policy on Information Standards Under the Endangered Species 
Act, published in the Federal Register on July 1, 1994 (59 FR 34271), 
and section 515 of the Treasury and General Government Appropriations 
Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) and the 
associated Information Quality Guidelines issued by the Service, 
provide criteria, establish procedures, and provide guidance to ensure 
that our decisions represent the best scientific data available. They 
require our biologists, to the extent consistent with the Act and with 
the use of the best scientific data available, to use primary and 
original sources of information as the basis for recommendations to 
designate critical habitat. When determining which areas contain 
features essential to the conservation of a species, a primary source 
of information is generally the listing package for the species. 
Additional information sources include the recovery plan for the 
species, 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. All information is used in 
accordance with the provisions of section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658) and the associated Information Quality Guidelines 
issued by the Service.
    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

[[Page 66911]]

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, but are outside the critical 
habitat designation, will continue to be subject to conservation 
actions implemented under section 7(a)(1) of the Act, to the regulatory 
protections afforded by the section 7(a)(2) of the Act jeopardy 
standard, and take under sections 9 and 10 of the Act if they support 
populations, 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

    As required by section 4(b)(1)(A) of the Act, we use the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of the California red-
legged frog. The sources of data used in identifying critical habitat 
include information in our files regarding habitat requirement of the 
subspecies including the data sources mentioned in the previous 
proposal (69 FR 19620), as well as information provided by commenters 
to that proposal. We also reviewed available information that pertains 
to the habitat requirements of this subspecies including data in 
reports submitted during section 7 consultations and by biologists 
holding section 10(a)(1)(A) recovery permits; research published in 
peer-reviewed articles and presented in academic theses and agency 
reports; and regional Geographic Information System (GIS) coverages. We 
designated no areas outside the geographic area presently occupied by 
the subspecies.
    In re-proposing critical habitat for the California red-legged 
frog, we changed our previous methodology of using the watershed as our 
primary mapping unit for the subspecies. Our current methodology 
includes a more precise mapping of the physical and biological features 
essential to the conservation of the California red-legged frog (i.e., 
primary constituent elements (PCEs)) (see below). This has resulted in 
significant differences between the units we proposed in April, 2004 
(69 FR 19620) and those we are proposing here. Additional changes have 
resulted from minor adjustments to the PCEs, and from an increased 
emphasis in the criteria on establishing the likely limits of occupied 
areas. See the section below, Criteria Used to Identify Critical 
Habitat, for a detailed listing of our selection criteria.

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 (PCEs) that are essential to the conservation of the species, 
within areas occupied by the species at the time of listing, 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 from disturbance or are 
representative of the historic geographical and ecological 
distributions of a species.
    Each of the areas designated in this rule have been determined to 
contain sufficient PCEs to provide for one or more of the life history 
functions of the California red-legged frog. As a result, the existing 
conditions at the time of designation will be included in the baseline 
in any consultation conducted subsequent to this designation. Federal 
actions that may result in alteration of these conditions will be 
subject to an analysis to determine whether adverse modification or 
destruction of critical habitat has occurred.

Aquatic Breeding Habitat

    California red-legged frogs typically lay eggs between December and 
early April. Eggs hatch within 6 to 14 days depending on water 
temperatures and require approximately 20 days to develop into 
tadpoles. Tadpoles in turn require anywhere between 11-20 weeks to 
develop into terrestrial frogs (Bobzien et al. 2000; Storer 1925; 
Wright and Wright 1949). Water bodies suitable for tadpole rearing must 
remain watered at least until the tadpoles metamorphose into adults, 
typically between July and September. Adult California red-legged frogs 
can survive in moist upland areas after breeding habitat has dried, and 
can live several years to make new breeding attempts. Therefore, 
aquatic breeding habitat need not be available every year, but it must 
do so often enough to maintain a California red-legged frog population 
during most years.
    Aquatic habitat is essential for providing space, food, and cover, 
necessary to sustain all life stages of California red-legged frogs. It 
consists of virtually all low-gradient fresh water bodies, including 
natural and manmade (e.g., stock) ponds, backwaters within streams and 
creeks, marshes, lagoons, and dune ponds. It does not include deep 
lacustrine water habitat (e.g., deep lakes and reservoirs 50 ac (20 ha) 
or larger in size).
    The aquatic habitat described as the first PCE is essential for 
frog breeding and for providing space, food, and cover necessary to 
sustain early life history stages of larval and juvenile California 
red-legged frogs. To be considered essential breeding habitat, the 
aquatic feature must have the capability to hold water for a minimum of 
15 weeks in all but the driest of years. This is the average amount of 
time needed for larvae to grow into metamorphosed juveniles so they can 
become capable of surviving in upland habitats. California red-legged 
frogs usually have completed metamorphosis between July and September. 
During periods of drought or less-than-average rainfall, these sites 
may not hold water long enough for individuals to complete 
metamorphosis. However, these sites would still contain features that 
are essential because they constitute breeding habitat in years of 
average rainfall. Without aquatic breeding habitats, the California 
red-legged frog would not survive, reproduce, develop juveniles, and 
grow into adult individual California red-legged frogs that can 
complete their life cycles.

Non-Breeding Aquatic Habitat

    The aquatic habitat described as the second PCE is essential for 
providing the space, food, and cover necessary to sustain California 
red-legged frogs. Non-breeding habitat consists of those aquatic 
elements identified above, but would also include, but not be limited 
to, other wetland habitats such as intermittent creeks, seeps, and 
springs. California red-legged frogs can use large cracks in the bottom 
of dried ponds as refugia to maintain moisture and avoid heat and solar 
exposure (Alvarez 2004). Without these non-breeding aquatic features 
California red-legged frogs would not be able to survive drought 
periods, or be able to disperse to other breeding habitat.

[[Page 66912]]

Upland Habitat

    Upland and riparian habitats associated with aquatic habitat is 
essential to maintain California red-legged frog populations associated 
with essential aquatic habitat. The associated upland and riparian 
habitat provide food and shelter sites for California red-legged frogs 
and assist in maintaining the integrity of aquatic sites by protecting 
them from disturbance and supporting the normal functions of the 
aquatic habitat. Upland habitat associated with occupied wetland 
habitat often contains blackberry (Rubus sp.) and other upland 
perennial species that provide for shelter from predatory species and 
forage habitat (Service 2002).
    Upland habitat that contains the features essential to the 
conservation of the species consists of natural areas within 200 ft (60 
m) of the edge of the riparian vegetation or dripline, or no further 
than the watershed boundary. This is based on the dispersal 
capabilities of the subspecies (see Dispersal Habitat below), and also 
research that has found in one study that the subspecies was capable of 
inhabiting upland habitats within 200 ft (60 m) of aquatic habitat for 
continuous durations exceeding 20 days (Bulger et al. 2003), and in 
another study, California red-legged frogs were observed inhabiting 
riparian habitat for durations up to 77 days (Rathbun et al. 1993). 
California red-legged frogs often disperse from their breeding habitat 
to forage and seek upland habitat if aquatic habitat is not available. 
Upland habitat includes structure that provides shade, moisture, and 
cooler temperatures. This structure may be natural such as the spaces 
under boulders or rocks and organic debris such as downed trees or 
logs; or it could be manmade including industrial debris and 
agricultural features, such as drains, watering troughs, abandoned 
sheds, or under stacks of hay or other vegetation. California red-
legged frogs also use small mammal burrows and moist leaf litter 
(Jennings and Hayes 1994; Fellers and Kleeman 2005).

Dispersal Habitat

    Dispersal habitat provides connectivity among California red-legged 
frog breeding habitat (and associated upland) patches. While California 
red-legged frogs can pass many obstacles, and do not require a 
particular type of habitat for dispersal, the habitat connecting 
breeding locations and other aquatic habitat must be free of barriers 
that prevent California red-legged frogs from dispersing. Dispersal 
habitat that is designated in this rule consists of upland and wetland 
habitat contiguous with breeding and non-breeding habitat which is free 
of barriers that connect two or more patches of breeding habitat within 
0.7 mi (1.2 km) of one another. Dispersal barriers include heavily 
traveled roads (Vos and Chardon 1998) that possess no bridges or 
culverts; moderate to high density urban or industrial developments 
with large expanses of asphalt or concrete that do not contain the PCEs 
or features essential to the subspecies; and large reservoirs over 50 
ac (20 ha) in size that contains predatory fish. Agricultural lands 
such as row crops, orchards, vineyards, and pastures do not constitute 
barriers to California red-legged frog dispersal.
    California red-legged frogs have been documented to travel 2.2 mi 
(3.6 km) from nonbreeding to breeding habitats (Bulger et al. 2003). 
These long distance movements are migrations rather than use of 
corridors for moving between habitats (N. Scott and G. Rathbun, in 
litt. 1998). These movements have also been found to be with apparent 
disregard to topography, vegetation type, or riparian corridors (Bulger 
et al. 2003; Fellers and Kleeman 2005). We conclude the 2.2 mi (3.6 km) 
is likely the upward limit of dispersal capability for the California 
red-legged frog and that the 0.7 mi (1.2 km) dispersal element will 
ensure that connectivity between breeding habitats will be maintained 
within areas designated as critical habitat. This 0.7 mi (1.2 km) 
dispersal element also includes elements of non-aquatic habitat (i.e., 
summer habitat) for shelter.

Primary Constituent Elements for the California Red-Legged frog

    Based on our current knowledge of the life history, biology, and 
ecology of the California red-legged frog and the requirements of the 
habitat necessary to sustain the essential life history functions of 
the subspecies, we have determined that the primary constituent 
elements for the California red-legged frog are:
    (1) Aquatic Breeding Habitat. Standing bodies of fresh water (with 
salinities less than 7.0 ppt), including natural and manmade (e.g., 
stock) ponds, slow moving streams or pools within streams, and other 
ephemeral or permanent water bodies that typically become inundated 
during winter rains and hold water for a minimum of 15 weeks in all but 
the driest of years. This would be the time necessary for the 
subspecies to complete the aquatic portion of its life cycle.
    (2) Non-Breeding Aquatic Habitat. Fresh water habitats as described 
above which may or may not hold water long enough for the subspecies to 
hatch and complete its aquatic lifecycle but which does provide for 
shelter, foraging, predator avoidance, and aquatic dispersal habitat 
for juvenile and adult California red-legged frogs. Other wetland 
habitat which would be considered to meet these elements would include, 
but are not limited to, plunge pools within intermittent creeks, seeps, 
quiet water refugia during high water flows, and springs of sufficient 
flow to withstand the summer dry period.
    (3) Upland Habitat. Upland areas within 200 ft (60m) of the 
surrounding aquatic and wetland habitat comprised of various 
vegetational series such as grasslands, woodlands, and/or wetland/
riparian plant species. Upland habitat includes natural or manmade 
structures such as the spaces under boulders or rocks and organic 
debris such as downed trees or logs; as well as agricultural features 
and light construction debris, such as drains, watering troughs, 
abandoned sheds, or under stacks of hay, brush piles, or other 
vegetation. California red-legged frogs also use small mammal burrows 
and moist leaf litter as cover (Jennings and Hayes 1994; Fellers and 
Kleeman 2005). This upland habitat provides the California red-legged 
frog shelter and shade, moisture, cooler temperatures, prey base, 
foraging opportunities, and predator avoidance.
    (4) Dispersal Habitat. Accessible upland or wetland dispersal 
habitat within designated units and between occupied locations within 
0.7 mi (1.2 km) of each other that allow for movement between such 
sites. Dispersal habitat includes various natural habitats and altered 
habitats such as agricultural fields, which also do not contain 
barriers to dispersal, such as heavily traveled roads (Vos and Chardon 
1998) that possess no bridges or culverts. Dispersal habitat does not 
include moderate to high density urban or industrial developments with 
large expanses of asphalt or concrete and large reservoirs over 50 ac 
(20 ha) in size, which do not contain those features identified in PCE 
1, 2, or 3. Accessible dispersal habitat provides opportunities for the 
California red-legged frog to move freely across the landscape in 
search of adjacent breeding and non-breeding habitats. Accessible 
dispersal habitat is considered essential and provides for: (1) 
Opportunities for movement and establishment of home ranges by juvenile 
recruits, (2) maintaining gene flow by the movement

[[Page 66913]]

of both juveniles and adults between subpopulations, and (3) 
recolonization of or recruitment into breeding habitat after local 
extirpations.

Criteria Used To Identify Critical Habitat

    In our proposed designation of critical habitat for the California 
red-legged frog, we selected areas based on the best scientific data 
available that possess those physical and biological features essential 
to the conservation of the subspecies, and that may require special 
management considerations or protection. We included areas which were 
occupied at the time of listing as well as some areas subsequently 
identified as occupied. We found that the majority of newer occurrence 
records were within areas already known to support the California red-
legged frog. We identified proposed critical habitat units that have 
the highest likelihood to be self-sustaining on the basis of density of 
California red-legged frog occurrences, and based our definition of the 
primary constituent elements on the kind, amount, and quality of 
habitat associated with those occurrences. The proposed units contain 
sufficient PCEs to support behaviors we have determined are essential 
to the conservation of the subspecies.
    Throughout the development process, we avoided identifying areas 
with single occurrences for designation unless such areas were 
considered unique or had other biological significance. Further, we 
made an effort to avoid developed areas, such as housing and commercial 
developments, that are unlikely to contribute to the conservation of 
the California red-legged frog. We also avoided fragmented areas such 
as those surrounded by development. Areas within the boundaries of the 
mapped units, such as buildings, roads, parking lots, railroads, 
canals, levees, airport runways and other paved areas, lawns, and other 
urban landscaped areas are not critical habitat and are not included in 
this designation. Federal actions limited to these areas would not 
trigger a section 7 consultation, unless they affect the subspecies 
and/or the PCEs in adjacent critical habitat. We avoided known areas of 
intensive agriculture. Agricultural lands may have been included if 
they were within areas identified as necessary for dispersal or 
connectivity between known occurrences.
    We considered several criteria in the selection of areas which 
contain the essential features for the California red-legged frog and 
focused on designating units: (1) Throughout the current geographic, 
elevational, and ecological distribution of the subspecies; (2) which 
would maintain the current population structure across the subspecies' 
range; (3) that retain or provide for connectivity between breeding 
sites that allows for the continued existence of viable and essential 
metapopulations, despite fluctuations in the status of subpopulations; 
(4) that possess large continuous blocks of occupied habitat, 
representing source populations and/or unique ecological 
characteristics; and (5) contain sufficient upland habitat around each 
breeding location to allow for sufficient survival and recruitment to 
maintain a breeding population over the long term.
    We first determined the occupancy status of areas. Areas were 
considered to possess extant populations if California red-legged frogs 
have been documented in that area since 1976. We used the final listing 
rule to establish occupancy at the time of listing. All other 
designations were based on occupancy data collected since listing. Our 
designation does not include all occupied areas. However those areas 
occupied takes into consideration theories of metapopulation 
persistence, on-the-ground survey data, and California red-legged frog 
longevity. We believe that persistence of individual populations is 
critical to the viability of a metapopulation structure. Bulger et al. 
(2003) found more than 75 percent of California red-legged frogs are 
resident at permanent aquatic habitats over the course of a year, 
thereby providing local population stability. Survey data provided to 
us during the development of this proposed critical habitat rule show 
an average persistence of 19 years for California red-legged frog 
populations. Additionally, maximum longevity of male and female 
California red-legged frogs is 8 and 10 years respectively (Jennings et 
al. 1992) which also contributes to generational and metapopulation 
stability.
    The extant occurrences within the proposed critical habitat units 
comprise approximately 63 percent of extant occurrences within the 
range of the subspecies. We critically evaluated records in which the 
exact site location was not precisely identified or could not be 
confirmed, and removed those locations from our analysis. We then 
selected areas that 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 which have other 
unique ecological significance, with the goal of maintaining the full 
range of the habitat variability and evolutionary adaptation in the 
subspecies. These include areas on the periphery of the current range 
and elsewhere that represents the distribution of the subspecies, and 
areas that provide connectivity among source populations or between 
source populations.
    The proposed critical habitat units were delineated by creating 
approximate areas for the units by screen digitizing polygons (map 
units) using ArcMap (Environmental Systems Research Institute, Inc.), a 
computer GIS program. The polygons were created by overlaying extant at 
time of listing and subsequent to listing California red-legged frog 
occurrence locations with a 0.7 mi (1.2 km) radius. This distance was 
used as a guide for mapping the essential features around locations 
where California red-legged frog populations are present (see Dispersal 
Habitat above). As stated above, California red-legged frogs have been 
documented to disperse from ponds and streams a distance over 2.0 mi 
(3.2 km) (Bulger et al. 2003). However, based on a review of the most 
current literature and information gathered in development of the 
Recovery Plan for the subspecies, we have determined that the 2.0 mi 
(3.2 km) distance is toward the maximum dispersal distance for the 
subspecies during a single season, and that the 0.7 mi (1.2 km) 
distance is more reflective of the average dispersal distance for the 
California red-legged frog (Rathbun et al. 1993; Scott and Rathbun, in 
litt 1998; Wright, in litt. 1999; Bulger et al. 2003; T. Tatarian, in 
litt. 2005; Fellers and Kleeman 2005). Although the studies discussed 
above provide an approximation of the distances that California red-
legged frogs can move from their aquatic habitats, breeding ponds, and 
other wetland habitats in search of suitable upland refugia or other 
breeding locations, we recognize that upland habitat features will 
influence California red-legged frog 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 beyond the 0.7 mi (1.2 km) distance where 
appropriate to aggregate clumps of occurrences. In other some 
instances, we reduced the areas to remove non-habitat (those not 
exhibiting the PCEs) from the proposed designation including 
agricultural, developed, disturbed, or fragmented lands.
    We evaluated the resulting units (delineating geographic range and 
potential suitable habitat), refined

[[Page 66914]]

elevation and hydrologic ranges, and identified areas not containing 
the essential features (i.e., not containing PCEs) (see Primary 
Constituent Elements section). We excluded areas that do not contain 
sufficient PCEs to support one or more of the species' life processes 
or which had low quality PCEs because: (1) The area is highly degraded 
and is likely not restorable; (2) the area is small, highly fragmented, 
or isolated and may provide little or no long-term conservation value; 
and (3) other areas within the geographic region were determined to be 
sufficient to meet the conservation needs of the subspecies.
    Throughout the designation process, when selecting areas of 
critical habitat, we made an effort to avoid developed areas, such as 
housing developments and commercial developments that are unlikely to 
contribute to the conservation of the California red-legged frog. 
However, we were not able to map critical habitat in sufficient detail 
to exclude all developed areas, or other lands unlikely to contain the 
PCEs.
    Further refinement of the preliminary areas as described above was 
based on the extent of aquatic habitat extent, stream reach, upland 
dispersal distance and watershed boundaries. We focused on areas of 
high California red-legged frog abundance, areas to maintain 
connectivity, and/or areas of unique ecological significance. Refined 
unit boundaries were delineated using watershed boundaries from the 
State of California's CALWATER watershed classification system (version 
2.2) using the smallest (planning watersheds) watershed designation. 
Visual inspection of mapped California red-legged frog occurrence 
records revealed un-surveyed regions surrounded by surveyed regions, 
mostly in highly developed areas. Rather than designating critical 
habitat in the development fringe, we designated in areas where fewer 
surveys have been conducted but where California red-legged frogs are 
likely to occur based on similarity of habitat and presence of PCEs. In 
areas where planning watersheds were large and/or had significantly 
altered hydrologically, we used alternative structural, political, or 
topographic boundaries (e.g., roads, county boundaries, ridgeline 
features, elevation contour lines) as critical habitat boundaries 
because in these areas the benefits of using planning watersheds were 
limited in that they included areas outside the subspecies' dispersal 
distance or were of little conservation value for the California red-
legged frog.

Summary of Changes From Previous Proposed Critical Habitat

    Following the publication of the previous proposed rule (69 FR 
19620), we revised this current proposed critical habitat based on new 
information, re-evaluation of existing information, and public 
comments. We also revised the methodology for determining the specific 
features that are essential to the conservation of the California red-
legged frog and mapping them to areas. Our previous proposal utilized 
aggregations of watersheds that contained areas of high California red-
legged frog abundance and that maintained connectivity and/or included 
areas of unique ecological significance. Portions of these areas were 
outside the dispersal capabilities of the frog and not all the areas 
within the designation contained the features considered essential to 
the California red-legged frog. This has resulted in a complete re-
analysis of the areas previously proposed and new areas where the frog 
had been recently documented to ensure a more thorough and 
scientifically sound designation of critical habitat. This re-analysis 
resulted in the removal of specific lands determined not to contain 
features essential to the conservation of the frog, and the inclusion 
of additional areas. The Service believes that this task was necessary 
to ensure compliance with recent court decisions on critical habitat 
and to ensure appropriate consideration of public comments and new 
information in the rulemaking process. Upon identification of lands 
containing features essential to the conservation of the frog following