Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae) and Taxonomic Revision, 45534-45604 [E8-16813]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 151 (Tuesday, August 5, 2008)]
[Rules and Regulations]
[Pages 45534-45604]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-16813]



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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; Designation of Critical 
Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae) 
and Taxonomic Revision; Final Rule

Federal Register / Vol. 73, No. 151 / Tuesday, August 5, 2008 / Rules 
and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2008-0014; 92210-1117-0000-B4]
RIN 1018-AV05


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis 
sierrae) and Taxonomic Revision

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are 
designating critical habitat for the Sierra Nevada bighorn sheep (Ovis 
canadensis sierrae) under the Endangered Species Act of 1973, as 
amended (Act). In total, approximately 417,577 acres (ac) (168,992 
hectares (ha)) fall within the boundaries of the critical habitat 
designation. The critical habitat is located in Tuolumne, Mono, Fresno, 
Inyo, and Tulare Counties, California. We also are finalizing the 
revision of taxonomy of the listed entity from a distinct population 
segment (DPS) of California bighorn sheep (Ovis canadensis 
californiana) to subspecies, Ovis canadensis sierrae, based on recent 
published information.

DATES: This rule becomes effective on September 4, 2008.

ADDRESSES: The final rule, economic analysis, and maps are available at 
https://www.regulations.gov and at https://www.fws.gov/nevada. Supporting 
documentation we used in the preparation of this final rule is 
available for public inspection, by appointment, during normal business 
hours, at the Nevada Fish and Wildlife Office, 1340 Financial 
Boulevard, Suite 234, Reno, NV 89523; telephone 775-861-6300; facsimile 
775-861-6301.

FOR FURTHER INFORMATION CONTACT: Robert D. Williams, U.S. Fish and 
Wildlife Service, Nevada Fish and Wildlife Office (see ADDRESSES 
section). If you use a telecommunications device for the deaf (TDD), 
call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat in this rule. For more information 
on the Sierra Nevada bighorn sheep, refer to the final listing rule 
published in the Federal Register on January 3, 2000 (65 FR 20) and the 
proposed critical habitat rule published in the Federal Register on 
July 25, 2007 (72 FR 40955).
    The bighorn sheep (Ovis canadensis) is a large mammal in the family 
Bovidae described by Shaw in 1804 (Shackleton 1985, p. 1). Cowan (1940, 
pp. 519-569) recognized several subspecies based on geography and skull 
measurements. Recent genetic (Ramey 1993, pp. 62-86; 1995, p. 432-434; 
Boyce et al. 1996, pp. 423-426, 429; Gutierrez-Espeleta et al. 1998, 
pp. 7-9, 11) and morphological data (Wehausen and Ramey 1993, pp. 4-8; 
2000, pp. 148-153), and review and reanalysis of Cowan's data (Ramey 
1993, p. 83), do not support Cowan's original subspecies 
differentiations.
    Ramey (1993, pp. 71-72; 1995, p. 432) found, based on mitochondrial 
DNA (mtDNA), bighorn sheep from the Sierra Nevada to be more allied 
with sheep occupying the adjacent desert area than those to the north. 
Ramey (1993, pp. 67-68; 1995, pp. 433, 435) also found Sierra Nevada 
bighorn sheep to be a distinctive group in the desert region extending 
east to Utah and New Mexico and south to northern Mexico. Ramey (1993 
p. 54) used mtDNA as a genetic marker to help understand the 
evolutionary history of North American mountain sheep. From the 116 
individuals included in the surveys, 16 different mtDNA haplotypes were 
identified in North America and four in Asia (Ramey 1993, p. 62). Two 
major mtDNA lineages of mountain sheep were indicated in North America 
(Ramey 1993, p. 63). Within the northern Alaska and western North 
America clade, three mtDNA lineages were identified (Ramey 1993, p. 
72). One lineage included bighorn sheep in the desert ranges of the 
southwestern United States and Mexico and the Sierra Nevada (Ramey 
1993, p. 72), where the Sierra Nevada population was found to be more 
closely related to the desert-dwelling sheep than those from the 
Cascade Ranges or Rocky Mountains (Ramey 1993, p. 72). Within the 
desert-dwelling sheep populations, Sierra Nevada bighorn sheep differed 
(Ramey 1993, p. 73). Ramey (1995 p. 429) used mtDNA as a genetic marker 
to help understand the evolutionary history of North American mountain 
sheep in the southwest United States. Ten mtDNA haplotypes were 
identified in the southwest, with a common one being found in most 
populations (Ramey 1995, pp. 431-432). The distribution of mtDNA 
variants in the southwest did not support the recognition of O. c. 
cremnobates, O. c. mexicana, and O. c. nelsoni as distinct and separate 
subspecies, but the mtDNA analysis did show a unique fixed haplotype 
for O. c. californiana from the Sierra Nevada (Ramey 1995, p. 433). 
Based on this finding, bighorn sheep from the Sierra Nevada could be 
distinguished from populations of other subspecies of bighorn sheep 
(Ramey 1995, p. 433). Results indicated that significant differences in 
mtDNA haplotype frequencies can be found among populations that are 
adjacent to one another and separated by short distances (Ramey 1995, 
p. 435). A few rare haplotypes were limited in distribution and found 
in only single populations. One of these populations included the 
Sierra Nevada (Ramey 1995, p. 433).
    Wehausen and Ramey (2000, pp. 148-153) used univariate and 
multivariate statistical methods to examine the geographic variation in 
horn and skull characters of 694 bighorn sheep (Ovis canadensis) from 
the Great Basin to British Columbia and Alberta. California bighorn 
sheep (O. c. californiana) from Washington and British Columbia were 
not distinguishable from Rocky Mountain bighorn sheep (O. c. 
canadensis); however, they did differ from Sierra Nevada bighorn sheep 
populations considered to be O. c. californiana. Extirpated populations 
from northeastern California, Oregon, and southwestern Idaho shared a 
horn-related character with Nelson bighorn sheep (O. c. nelsoni) from 
the Great Basin; this shared character was different from Rocky 
Mountain bighorn sheep. Individuals from the Sierra Nevada were 
distinguishable from bighorn sheep from the Great Basin. These results 
agree with geographic patterns identified with the mtDNA studies of 
Ramey (1993, 1995) (Wehausen and Ramey 2000, p. 156). Wehausen and 
Ramey (2000, pp. 153-157) synonymized the extinct Audubon subspecies, 
O. c. auduboni, from east of the Rocky Mountains in eastern Montana and 
Wyoming, North Dakota, South Dakota, and western Nebraska with O. c. 
canadensis. They also assigned extinct and extant native populations of 
O. c. californiana from Washington and British Columbia to O. c. 
canadensis and the extinct native populations of O. c. californiana 
from northeastern California, northern Nevada, southwestern Idaho, and 
Oregon to O. c. nelsoni of the Great Basin desert form. Based on 
genetic and morphometric data, Wehausen and Ramey (2000, p. 156) 
concluded that bighorn sheep in the Sierra Nevada should be recognized 
as a separate subspecies of O. canadensis, but they

[[Page 45535]]

did not recommend a change in nomenclature at that time.
    In a recent investigation of the taxonomy of Sierra Nevada bighorn 
sheep, Wehausen et al. (2005) reexamined the history of bighorn sheep 
nomenclature. Grinnell (1912, p. 144) recognized bighorn sheep from the 
Sierra Nevada of California as a distinct subspecies, Ovis cervina (= 
canadensis) sierrae, designating a 5-year-old ram as the type specimen. 
Cowan (1940, p. 556) did not recognize the subspecies O. c. sierrae as 
valid, but included animals from the Sierra Nevada as O. c. 
californiana. Wehausen and Ramey (2000, pp. 153-157) reassigned 
specimens from north of the central Sierra Nevada to O. c. nelsoni and 
O. c. canadensis. They kept the name O. c. californiana for bighorn 
sheep in central and southern Sierra Nevada (Wehausen and Ramey 2000, 
p. 156), raising the question of the correct subspecific name for 
animals inhabiting this area. Based on this investigation of the 
taxonomy of Sierra Nevada bighorn sheep and by the Principle of 
Typification (International Commission on Zoological Nomenclature 
1999), cited in Wehausen et al. (2005, p. 217), Wehausen et al. (2005 
p. 217) concluded, based on Grinnell's original type specimen, that the 
correct nomenclature for native sheep in the central and southern 
Sierra Nevada of California is Ovis canadensis sierrae (Grinnell). 
Therefore, with the publication of this final rule designating critical 
habitat for the Sierra Nevada bighorn sheep, we formally revise its 
taxonomy from DPS of California bighorn sheep (Ovis canadensis 
californiana) to subspecies Ovis canadensis sierrae.
    Sierra Nevada bighorn sheep inhabit portions of the Sierra Nevada 
located along the eastern boundary of California in Tuolumne, Mono, 
Fresno, Inyo, and Tulare Counties. Habitat occurs from the eastern base 
of the range as low as 4,790 feet (ft) (1,460 meters (m)) to peaks 
above 14,100 ft (4,300 m) (Wehausen 1980, pp. 3, 82).
    Based on recent modeling efforts, discussed further in the Criteria 
Used To Identify Critical Habitat section, Sierra Nevada bighorn sheep 
habitat, as well as areas necessary to provide connectivity between 
winter and summer ranges, occur as low as 4,000 ft (1,219 m) in the 
southern portion of its range (Johnson et al. 2005). Sierra Nevada 
bighorn sheep inhabit open areas where the land is rocky, sparsely 
vegetated, and characterized by steep slopes and canyons (Wehausen 
1980, p. 81; Sierra Nevada Bighorn Sheep Interagency Advisory Group 
1997, p. 5). Wehausen (1980, pp. 18-25) provides a detailed description 
of Sierra Nevada bighorn sheep habitat throughout its range. They 
prefer open ground to better detect predators and allow enough time to 
reach steep, rocky terrain (escape habitat) (Wehausen 1980, p. 81). 
Forests and thick brush are usually avoided if possible (65 FR 21; 
January 3, 2000). Most of the sheep live at higher elevations (10,000-
14,000 ft (3,050-4,270 m)) in subalpine and alpine areas during the 
summer (65 FR 21; January 3, 2000). During winter, these sheep occupy 
high-elevation, windswept ridges and tend to prefer south-facing slopes 
where snow melts more readily (Jones 1950, pp. 44-45; McCullough and 
Schneegas 1966, p. 71; Wehausen 1980, pp. 86-87) or migrate to lower 
elevations (4,800 ft (1,460 m)) in sagebrush-steppe areas to avoid deep 
snow and to find forage.
    Sierra Nevada bighorn sheep are gregarious, with group size and 
composition depending on gender and season. Spatial segregation by 
gender occurs outside of the mating season. Bighorn sheep ewes 
generally remain with the same band in which they were born (Cowan and 
Geist 1971, pp. 80-81). Males older than 2 years of age remain apart 
from females and younger males for most of the year (Jones 1950, p. 50; 
Cowan and Geist 1971, p. 65; Wehausen 1980, p. 109). During the late 
fall and winter, the groups come together and concentrate in suitable 
winter habitat.
    Breeding takes place in late fall, generally November and December 
(Jones 1950, pp. 63-64; Cowan and Geist 1971, p. 64; Wishart 1978, p. 
165). Lambing occurs between late April and early July (Wehausen 1996, 
p. 475) on safe, precipitous, rocky slopes (Wehausen 1980, p. 95); most 
lambs in the Sierra Nevada are born in May and June (Wehausen 1980, p. 
94; 1996, p. 475). Ewes and lambs often occupy steep terrain that 
provides a diversity of exposures and slopes for escape cover (65 FR 
21; January 3, 2000). The lifespan for both Sierra Nevada bighorn sheep 
males and females has been observed as 8 to 12 years (Wehausen 1980, p. 
76; Stephenson 2008, p. 1).
    Bighorn sheep are primarily diurnal (Jones 1950, pp. 54-57). They 
are primarily grazers; however, they may browse woody vegetation at 
times. Plants consumed include various grasses, browse, and forbs, 
depending on season and location (Wehausen 1980, pp. 80-93). Naturally 
occurring and mineral licks provide necessary minerals for bone and 
muscle growth.
    While distribution of bighorn sheep is naturally fragmented on the 
landscape, the maintenance of migration corridors (space) is important 
to allow genetic exchange between Sierra Nevada bighorn sheep herds. 
The population ecology of bighorn sheep has been described as a 
metapopulation with geographically distinct herds interacting in a 
network (Schwartz et al. 1986, p. 184; Bleich et al. 1990, pp. 384-
388). The movements of rams between herds can counteract the effects of 
inbreeding that can develop with small, isolated populations (Schwartz 
et al. 1986, pp. 182-185).

Previous Federal Actions

    On April 20, 1999, we published an emergency rule listing the 
Sierra Nevada DPS of the California bighorn sheep as endangered (64 FR 
19300), providing emergency protection to the DPS until such time that 
we could complete the normal listing process. We also published a 
proposed rule to list the DPS as endangered on the same date (64 FR 
19333). On January 3, 2000, we published a final rule listing the 
Sierra Nevada bighorn sheep as endangered (65 FR 20). The emergency 
rule stated that the designation of critical habitat was not 
determinable due to lack of information sufficient to perform the 
required analysis of impacts of the designation. In the final listing 
rule, we stated our revised determination that there is sufficient 
information to perform the required impact analysis and that the 
designation of critical habitat is prudent.
    During the process of designating critical habitat for the Sierra 
Nevada bighorn sheep, we noticed that the final listing rule published 
in 2000 (65 FR 20) inadvertently listed this entity as a DPS rather 
than as a subspecies. While the listing rule addressed the DPS 
question, we failed to include the DPS language in the table found in 
the regulatory section of the rule. However, as stated above, based on 
the work of Wehausen and Ramey (2000, p. 156) and Wehausen et al. 
(2005, p. 217), the Sierra Nevada bighorn sheep is recognized as a 
subspecies, and the correct nomenclature is Ovis canadensis sierrae. 
Therefore, we are formally providing a taxonomic revision herein to 
amend the final listing rule to subspecies Ovis canadensis sierrae.
    On July 30, 2003, we made available the Service's Draft Recovery 
Plan for the Sierra Nevada Bighorn Sheep (Ovis canadensis californiana) 
(68 FR 44808). On October 9, 2003, we reopened the comment period for 
the draft Recovery Plan (68 FR 58355). On February 13, 2008, we 
published a Notice of Availability for the final recovery plan (73 FR 
8345).

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    On December 8, 2005, the Center for Biological Diversity filed a 
complaint based on the Service's failure to designate critical habitat 
for this subspecies within the time mandated under the Act (Center for 
Biological Diversity v. U.S. Fish and Wildlife Service, et al. Case No. 
2:05-CB-02492-DFL-KJM). On June 6, 2006, the Service entered into a 
settlement agreement with the Center for Biological Diversity to submit 
a proposed critical habitat designation for this subspecies for 
publication in the Federal Register by July 17, 2007, and to submit a 
final determination on the proposed critical habitat designation for 
publication by July 17, 2008.
    Our proposed critical habitat rule and taxonomic revision for the 
Sierra Nevada bighorn sheep was published in the Federal Register on 
July 25, 2007 (72 FR 40956). A notice of availability of the draft 
economic analysis (DEA) of the proposed critical habitat designation 
was published in the Federal Register on February 5, 2008 (73 FR 6684). 
This final rule satisfies the June 6, 2006, settlement agreement with 
respect to Sierra Nevada bighorn sheep.
    For more information on previous Federal actions concerning Sierra 
Nevada bighorn sheep, refer to the final listing rule published in the 
Federal Register on January 3, 2000 (65 FR 20).

Summary of Comments and Recommendations

    We requested written comments from the public on the proposed 
designation of critical habitat for the Sierra Nevada bighorn sheep 
published on July 25, 2007 (72 FR 40956). The 60-day comment period for 
the proposed rule closed on September 24, 2007. A request for a comment 
period extension was received from a private organization on August 20, 
2007, and on October 9, 2007, the comment period was reopened until 
November 23, 2007 (72 FR 57276). A 30-day comment period was opened on 
the DEA and the proposed rule on February 5, 2008, and closed on March 
6, 2008 (73 FR 6684). Comments and new information received in response 
to the proposed rule and the DEA were incorporated in the final rule as 
appropriate and summarized below.
    During the comment periods for the proposed rule, we received a 
total of 28,181 (28,153 in support, 12 opposed, and 16 neutral) 
comments from Federal, State, and local governments, non-governmental 
organizations and private individuals. We received two requests for 
public hearings. The Inyo County Board of Supervisors made a request 
for a public hearing on August 7, 2007, as did two private individuals 
on August 29, 2007. A public hearing was held in Bishop, California, on 
October 25, 2007 (72 FR 57276). We received 12 oral testimonies from 12 
individuals. Of these commenters, three who provided oral comments also 
submitted duplicative written comments. A request was made for a public 
workshop by the Mono County Board of Supervisors on September 5, 2007. 
We held two public meetings in Bridgeport and Bishop, California, on 
October 24 and 25, 2007, respectively (72 FR 57276).

Peer Review

    In accordance with our policy published July 1, 1994 (59 FR 34270), 
we solicited expert opinions from three knowledgeable individuals with 
scientific expertise that included familiarity with the species and 
conservation biology principles. We received responses from two peer 
reviewers. In general, the peer reviewers concurred with our methods 
and conclusions and provided suggestions to improve the final critical 
habitat rule.
    We reviewed all comments received from the peer reviewers and the 
public for substantive issues and new information regarding critical 
habitat for the Sierra Nevada bighorn sheep, addressed them in the 
following summary, and incorporated them into the final rule as 
appropriate.

Peer Reviewer Comments

    (1) Comment: Both peer reviewers raised concern that the proposed 
designation did not adequately protect Sierra Nevada bighorn sheep from 
the possible introduction of disease from domestic sheep and goats. One 
suggested that the ``absence of risk of disease transmission'' should 
be explicitly included as a primary constituent element (PCE) as 
pneumonia caused by contact with domestic sheep or goats can be an 
overriding factor affecting habitat suitability.
    Our Response: Conservation of the Sierra Nevada bighorn sheep 
depends on addressing both habitat and non-habitat related threats. In 
terms of the consultation process under section 7(a)(2) of the Act, the 
Service is required to analyze both the threats to the individuals 
within a population and the threats to the PCEs of its designated 
critical habitat. Under the Special Management Considerations or 
Protection section, we have indicated that management of domestic 
livestock grazing practices that result in overgrazing or forage 
competition between these domestic species and Sierra Nevada bighorn 
sheep can be a threat. The concern for overgrazing or competition is a 
habitat-related threat associated with the PCEs (i.e., PCE 2). The 
potential for contact and the possible transmission of disease to 
bighorn sheep exists when domestic sheep or goats are present in 
critical habitat. Management of the threat of disease transmission 
between domestic sheep and goats and Sierra Nevada bighorn sheep is 
needed to conserve this species; however, this threat is not strictly a 
habitat-related threat. The potential effects of disease transmission 
will be addressed through section 7 consultation with Federal agencies 
under the jeopardy standard and through the section 9 prohibitions of 
the Act to the extent applicable. There would be no benefit gained from 
a critical habitat designation with respect to the effects of disease 
on individual Sierra Nevada bighorn sheep because the regulatory 
effects of critical habitat designations apply to adverse modification 
or destruction of habitat, not to effects that result in the mortality 
of individual Sierra Nevada bighorn sheep. Because the disease threat 
faced by the species is not habitat-based, there would be no practical 
benefit to including it as a PCE.
    (2) Comment: One peer reviewer suggested that buffer zones be 
established around designated critical habitat for management of 
domestic sheep and goats because activities that could pose a risk of 
disease transmission do not need to occur directly within critical 
habitat to affect that habitat.
    Our Response: The units designated as critical habitat for the 
Sierra Nevada bighorn sheep contain the features essential for the 
conservation of this subspecies. It is not our practice to establish 
buffers around an area designated as critical habitat. As indicated 
under the Special Management Considerations or Protection section, 
domestic sheep and goat grazing may require management modifications to 
protect Sierra Nevada bighorn sheep in critical habitat in certain 
units. Any buffer distance recommended or suggested in a Federally 
proposed action involving domestic sheep or goat grazing adjacent to a 
designated critical habitat unit to reduce the potential threat of 
disease transmission to Sierra Nevada bighorn sheep would be taken into 
consideration during the jeopardy analysis of the consultation process 
under section 7 of the Act.
    (3) Comment: One peer reviewer raised concern for an elevated risk 
of disease transmission with domestic sheep grazing on U.S. Forest 
Service

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(USFS) lands as Sierra Nevada bighorn sheep wander between units.
    Our Response: We are aware of the potential risk of disease 
transmission due to contact between domestic sheep (and goats) and 
Sierra Nevada bighorn sheep. If a disease outbreak were to occur in a 
Sierra Nevada bighorn sheep population, it could be passed to other 
populations (units) because of, most likely, ram forays. This risk will 
increase if Sierra Nevada bighorn sheep numbers increase as expected 
due to continuing recovery actions. While we believe that this is an 
issue of management concern, we do not believe that this critical 
habitat designation necessarily affects the issue in any significant 
way. Please also see our response to comment (1).
    (4) Comment: Both peer reviewers raised concern that the proposed 
critical habitat designation did not provide biologically based 
corridors or linkage zones for movements among Sierra Nevada bighorn 
sheep subpopulations. They were unclear how genetic exchange or 
colonization would be allowed with unconnected units of critical 
habitat.
    Our Response: Connectivity, within a critical habitat unit, is a 
PCE for the Sierra Nevada bighorn sheep (i.e., PCE 1). The current 
critical habitat configuration provides for long-term connectivity 
between groups within a particular unit. We recognize the importance of 
migration between critical habitat units, as discussed under 
Metapopulaton Structure in the Space for Individual and Population 
Growth and for Normal Behavior section. However, due to the current 
isolation of occupied herd units and extremely limited knowledge of 
various migration paths that Sierra Nevada bighorn sheep, especially 
rams, may have taken historically between units, we did not develop 
criteria that would capture migration corridors between units.
    (5) Comment: One peer reviewer was concerned about the fine-scale 
mapping resulting in ``finger-like'' habitats for Units 1, 2, 3, 4, and 
9. The concern was related to possible difficulties in managing such 
areas. The reviewer suggested the boundaries be redrawn to reduce 
sinuosity, possibly along watershed and or drainage boundaries.
    Our Response: The critical habitat units have been developed to be 
consistent with the herd units that the Sierra Nevada bighorn recovery 
plan identifies as essential for recovery of the subspecies. Those herd 
units were originally developed using expert opinion and information on 
current and historical bighorn sheep locations in the Sierra Nevada. 
Those units were later refined using a habitat selection model 
developed by University of California Davis and the California 
Department of Fish and Game (CDFG) (Johnson et al. 2005). Based on our 
analysis of the biological needs of the subspecies, we believe that the 
herd units developed for the recovery plan capture those areas that 
contain the physical and biological features arranged in the 
appropriate quantity and spatial arrangement for the conservation of 
the subspecies.
    It is important to remember that these critical habitat units are 
not being established as Sierra Nevada bighorn sheep preserves or 
management zones. These are regulatory designations of areas that 
contain the features essential to the conservation of the subspecies. 
Critical habitat would serve its regulatory role when analyzing a 
particular Federal action in the consultation process under section 
7(a)(2) of the Act to determine if that action would adversely modify 
or destroy critical habitat by impacting the essential features within 
that unit to such a degree that the unit no longer serves its function 
for conservation.
    It is possible that a Federal action immediately adjacent to these 
units (e.g., between ``fingers'') could indirectly adversely modify 
critical habitat within the units. In such a situation, the action 
would be analyzed through the consultation process under section 
7(a)(2) of the Act against the adverse modification standard. However, 
because our analysis has not identified essential features in these 
locations, unit boundary modification and designation of critical 
habitat therein would not be appropriate.
    (6) Comment: One peer reviewer commented that the indicated 9 to 11 
year lifespan for bighorn sheep seemed short.
    Our Response: We have modified the Background section of the final 
rule to more accurately reflect the observed lifespan for male and 
female bighorn sheep in the Sierra Nevada.

Comments From State Agencies

    (7) Comment: California Department of Fish and Game (CDFG) 
suggested a PCE that identifies a ``disease-free zone'' because of the 
risk to Sierra Nevada bighorn sheep in proximity to domestic sheep.
    Our Response: Please see our response to Comment 1.
    (8) Comment: CDFG recommended establishment of a buffer that 
excludes domestic sheep to ensure the integrity of the critical habitat 
for Sierra Nevada bighorn sheep and provide additional protections.
    Our Response: Please see our response to Comment 2.
    (9) Comment: CDFG recommended more emphasis be placed on the use of 
fire to maintain critical habitat because fire is an integral part of 
the landscape.
    Our Response: The Special Management Considerations or Protection 
section identifies activities of Federal agencies or those with a 
federal nexus that may impact Sierra Nevada bighorn sheep and their 
habitat. The section is not meant to promote or discourage any 
particular activity. We indicated that it may be necessary in some of 
the critical habitat units to reduce forest cover to make habitat more 
suitable for Sierra Nevada bighorn sheep. Prescribed fire can be used 
as a tool to do this. Johnson et al. (2005, p. 34) indicate Sierra 
Nevada bighorn sheep could gain additional habitat with a reduction in 
forest cover. In addition, the final recovery plan (Appendix H, Genetic 
Management of Sierra Nevada Bighorn Sheep) provides a specific 
recommendation to use fire in addition to other methods to enhance 
habitat within herd units (Service 2007, p. 174). This would improve 
unit carrying capacity, as well as connectivity with adjacent herd 
units, providing better opportunities for genetic exchange between 
herds.
    (10) Comment: California Department of Food & Agriculture (CDFA) 
commented that there is ``still incomplete agreement in the scientific 
community'' about disease transmission from domestic sheep to bighorn 
sheep, in general, such as how often it occurs and its role in disease 
epizootics in bighorn sheep. The CDFA agrees that a reasonable approach 
is to keep the two species separated. How such separation occurs and 
what measures are used to prevent possible contact are important to 
both the survival of Sierra Nevada bighorn sheep and the domestic sheep 
industry in Inyo and Mono Counties, California. The CDFA commented that 
further scientific findings will improve understanding of the true 
nature of respiratory disease in bighorn sheep, in general, and that 
interested parties should cooperate on common interests. They also 
noted that at the 111th Annual Meeting of the United States Animal 
Health Association (USAHA) in October 2007, a joint resolution passed 
recommending additional research and formation of a subcommittee. The 
College of Agriculture, Biotechnology and Natural Resources at the 
University of Nevada Reno (UNR) similarly mentions the USAHA 
resolution.
    Our Response: We are aware that disagreement continues regarding 
the potential for disease transmission to

[[Page 45538]]

occur between domestic livestock, especially sheep and goats, and 
bighorn sheep, in general, under range conditions. We have reviewed 
Resolution No. 15 that reads, ``The United States Animal Health 
Association (USAHA) urges the United States Secretary of Agriculture 
and the United States Secretary of the Interior to seek resources 
through the President's budget to fund research to better elucidate the 
epidemiology and pathogenesis of bighorn/domestic sheep disease 
interactions so informed and effective management decisions can be 
made.'' We, along with others, continue to seek answers to questions 
related to this disease transmission issue. We support continuing 
research efforts to address uncertainties and to assist in the 
decision-making process.
    (11) Comment: The CDFA recommends consideration of the Western 
Association of Fish and Wildlife Agencies' (WAFWA) document, 
``Recommendations for Domestic Sheep and Goat Management in Wild Sheep 
Habitat'', dated June 21, 2007, and the University of California--
Davis' ``Quantifying the Risk of Disease Transmission from Domestic 
Sheep to Bighorn Sheep in the Sierra Nevada'' in future determinations 
of effectively preventing the possibility of disease transmission 
between domestic sheep and Sierra Nevada bighorn sheep, in addition to 
working with livestock industry representatives.
    Our Response: We are aware of these documents and consider 
information contained within them during section 7 consultations, as 
appropriate. Other documents also support the effective separation of 
domestic sheep from bighorn sheep, in general, as a management tool to 
reduce the risk of contact and possible disease transmission (Wyoming 
State-wide Bighorn/Domestic Sheep Working Group 2004, pp. 7, 11; U.S. 
Forest Service 2006, pp. 18-19). Also, an expert science panel (U.S. 
Geological Survey and Bureau of Reclamation 2006) was convened in 2006 
to discuss a risk analysis of disease transmission between domestic and 
bighorn sheep on the Payette National Forest in Idaho. The panel 
focused on science-based concerns raised by the risk analysis document, 
specifically the disease/mortality category, and developed six 
statements. References to concerns about domestic sheep also apply to 
domestic goats. Three of these key statements follow: ``(1a) Scientific 
observation and field studies demonstrate that ``contact'' between 
domestic sheep and bighorn sheep is possible under range conditions. 
This contact increases risk of subsequent bighorn sheep mortality and 
reduced recruitment, primarily due to respiratory disease; (1b) The 
complete range of mechanisms/causal agents that lead to epizootic 
disease events cannot be conclusively proven at this point; and (1c) 
Given the previous two statements, it is prudent to undertake 
management to prevent contact between these species'' (U.S. Geological 
Survey and Bureau of Reclamation 2006, p. 1). One panelist dissented 
and preferred ``can increase risk'' in statement 1a because it did not 
imply that any contact will result in disease transmission (U.S. 
Geological Survey and Bureau of Reclamation 2006, p. 1).
    (12) Comment: The California Department of Transportation 
(CalTrans) states that roads are inconsistently addressed and that it 
is inappropriate to include state highway right-of-ways (ROWs) and 
facilities within critical habitat. It is recommended by CalTrans that 
State Route (SR) 120 in Unit 1 and SR 158 in Unit 2 be excluded from 
critical habitat.
    Our Response: When determining critical habitat boundaries for 
Sierra Nevada bighorn sheep, we made every effort to avoid including 
developed areas such as lands covered by buildings, paved areas, and 
other structures that lack PCEs for the Sierra Nevada bighorn sheep. 
The scale of the maps prepared under the parameters for publication 
within the Code of Federal Regulations may not reflect the exclusion of 
such developed areas. Any such features and the land under them 
inadvertently left inside critical habitat boundaries shown on the maps 
of this final rule have been excluded by text in the final rule and are 
not designated as critical habitat. Therefore, Federal actions limited 
to these areas would not trigger section 7 consultation, unless they 
may affect the species or PCEs in adjacent critical habitat.
    We have determined, however, that the unpaved road right-of-ways of 
SR 120 from Unit 1 and SR 158 from Unit 2 do contain the features 
essential to the conservation of the Sierra Nevada bighorn sheep, and 
therefore meet the definition of critical habitat. CalTrans did not 
provide, nor are we aware of any additional information of the benefits 
of excluding ROWs based on ongoing or planned management of these ROWs, 
or how any on-going or planned management of the ROWs would benefit the 
conservation of the Sierra Nevada bighorn sheep or the sheep itself.
    The Secretary may exclude an area from critical habitat under 
section 4(b)(2) of the Act after taking into consideration the economic 
impact, the impact on national security, and any other relevant impact 
if he determines that the benefits of such exclusion outweigh the 
benefits of designating such area as critical habitat, unless he 
determines that the exclusion would result in the extinction of the 
species concerned.
    Because we are not aware of any information describing the benefits 
of excluding ROWs based on ongoing or planned management of these ROWs, 
or how any existing or planned management provides the same or better 
level of protection from adverse modification or destruction than that 
provided through a consultation under section 7 of the Act, we have 
determined that exclusion of these lands from the final designation of 
critical habitat pursuant to section 4(b)(2) of the Act is not 
appropriate at this time.
    (13) Comment: CalTrans states that no bighorn sheep collisions with 
vehicles are listed in their accident database. This is contrary to a 
statement made in our proposed rule that a bighorn sheep collision with 
a vehicle had occurred in the past.
    Our Response: A CDFG employee was made aware of the collision we 
referenced in the proposed rule (72 FR 40956) through a third party. 
The employee contacted the motorist to obtain information about the 
November 2003 collision. The Sierra Nevada bighorn sheep ram was 
monitored after the collision by CDFG, and it subsequently died in 
January 2004. No formal report was made by CDFG to CalTrans (Stephenson 
2008, p. 1).
    (14) Comment: CalTrans indicates references to SR 190 should be 
corrected as SR 190 does not occur in or adjacent to critical habitat.
    Our Response: We erroneously indicated SR 190 occurred in or 
adjacent to Unit 10 in the Proposed Critical Habitat Designation and 
the Special Management Considerations or Protection sections. The road 
should have been indicated as Forest Route 16S02. This has been 
corrected in both sections.
    (15) Comment: CalTrans states that, although an alignment has not 
been selected for the proposed Olancha/Cartago U.S. 395 project, an 
alternative might occur on the west side of Los Angeles aqueduct.
    Our Response: We appreciate this information. If the location for 
this new road construction occurs within designated critical habitat or 
may impact the Sierra Nevada bighorn sheep or its designated critical 
habitat, consultation under section 7 of the Act will occur as 
appropriate.

[[Page 45539]]

    (16) Comment: The Nevada Department of Agriculture (NDOA) stated 
that the disease transmission risk assessment model by Clifford et al. 
(2007) is ``questionable'' as a tool for management and is a problem 
when serving as the basis of a critical habitat designation. The 
College of Agriculture, Biotechnology and Natural Resources at the 
University of Nevada Reno (UNR) similarly recommends that the disease 
risk assessment by Clifford et al. (2007) should not be used as the 
basis for designating Sierra Nevada bighorn sheep critical habitat.
    Our Response: We agree. Critical habitat as defined in section 3 of 
the Act is; the specific areas within the geographical area occupied by 
a species at the time it is listed in accordance with the Act, on which 
are found those physical or biological features essential to the 
conservation of the species and which may require special management 
considerations or protection; and specific areas outside the 
geographical area occupied by a species at the time it is listed, upon 
a determination that such areas are essential for the conservation of 
the species. Designation of critical habitat is not based on a single 
management issue and, in this case, the concern for transmission of 
diseases from the grazing of domestic sheep or goats in proximity to 
Sierra Nevada bighorn sheep did not serve as the foundation for this 
critical habitat designation. Domestic sheep grazing is a management 
issue that is properly addressed through the consultation process under 
section 7(a)(2) of the Act.
    (17) Comment: The NDOA recommended that the critical habitat 
designation be suspended until the scientific basis has been 
established for disease transmission between domestic sheep and Sierra 
Nevada bighorn sheep.
    Our Response: We are designating critical habitat for Sierra Nevada 
bighorn sheep in accordance with the deadlines established by a court-
approved settlement agreement. We agreed to submit to the Federal 
Register a final determination of critical habitat for Sierra Nevada 
bighorn sheep by July 17, 2008. We based our designation of critical 
habitat on the best scientific and commercial data available as 
required by Section 4 of the Act. Further, our Policy on Information 
Standards Under the Endangered Species Act (published in the Federal 
Register on July 1, 1994 (59 FR 34271)), the Information Quality Act 
(section 515 of the Treasury and General Government Appropriations Act 
for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated 
Information Quality Guidelines provide criteria, establish procedures, 
and provide guidance to ensure that our decisions are based on the best 
scientific data available. We used published scientific literature and 
the expertise of Recovery Team members (including scientists from a 
variety of federal and state agencies, and other publics). We also 
solicited peer review from individuals familiar with bighorn sheep, in 
general, and related issues. We solicited new biological data, invited 
public participation during multiple comment periods, conducted a 
public hearing, and held informational meetings on the proposed rule. 
We have considered peer review, agency, and public comments received 
during the preparation of this final rule. Accordingly, we have used 
the best scientific and commercial information available in this 
designation. Designation of critical habitat is not based on a single 
management issue and, in this case, the concern for transmission of 
diseases from the grazing of domestic sheep or goats in proximity to 
Sierra Nevada bighorn sheep did not serve as the foundation for this 
critical habitat designation.
    (18) Comment: The NDOA stated that uncertainties in general about 
bighorn sheep epizootics exist per the USAHA meeting in October 2007.
    Our Response: Please see our response to Comment 10.
    (19) Comment: The NDOA stated that the occurrence of bighorn sheep 
disease and die-offs can be associated with bighorn sheep reaching peak 
numbers (Monello et al. 2001). Stagnant bighorn sheep population 
numbers have occurred in association with predation by wolves and 
mountain lions. These factors affect bighorn sheep populations 
``permanently,'' not just ``temporarily'' like domestic sheep grazing.
    Our Response: Bighorn sheep mortalities can be attributed to 
various factors as discussed below in the ``Mortality Factors'' section 
of this rule. These mortality factors may or may not affect bighorn 
sheep populations ``permanently,'' depending on numerous variables. 
Die-offs from diseases possibly transmitted from domestic sheep can 
have long-lasting effects by influencing subsequent population 
recruitment. Lambs born to surviving ewes can experience low survival 
rates for 3 to 5 years after the initial outbreak (Foreyt 1990, p. 100; 
Coggins and Matthews 1992; Ward et al. 1992; Foreyt 1995; Hunter 1995a, 
as cited in Schommer and Woolever 2001, p. 3). We have added a short 
discussion in the Physical and Biological Features section related to 
these long-lasting impacts of pneumonia in bighorn sheep populations.
    (20) Comment: The NDOA and UNR stated that climate and geographical 
factors play a role in the recovery of a species and that the 
``northern recovery unit'' is neither suitable nor essential habitat in 
terms of winter range for the Sierra Nevada bighorn sheep due to its 
higher elevation and greater snow depths than more southern units.
    Our Response: As indicated in the Criteria Used to Identify 
Critical Habitat section, we used the following criteria to select 
areas occupied by the Sierra Nevada bighorn sheep at the time of 
listing for inclusion in critical habitat:
    (a) Those areas occupied by the Sierra Nevada bighorn sheep at the 
time of listing (1999-2000) as indicated in the final listing rule (65 
FR 20; January 3, 2000). In the final listing rule, we identified five 
subpopulations of Sierra Nevada bighorn sheep that existed: (1) Lee 
Vining Canyon (Mount Warren and Mount Gibbs Herd Units), (2) Wheeler 
Crest (Wheeler Ridge Herd Unit), (3) Mount Baxter (Sawmill Canyon and 
Mount Baxter Herd Units), (4) Mount Williamson (Mount Williamson Herd 
Unit), and (5) Mount Langley (Mount Langley Herd Unit) in Mono and Inyo 
counties, California (Wehausen 1999, pp. 1-7; 2000, pp. 1-6);
    (b) Areas that are representative of the distribution of the Sierra 
Nevada bighorn sheep throughout the geographical range occupied at the 
time of listing with the goal of maintaining the subspecies' range of 
habitat and genetic variability; and
    (c) Areas that allow for the continued existence of viable 
subpopulations under varying environmental conditions and that can 
serve as locations for source populations. The locations of all five 
subpopulations identified in the original listing rule continue to 
remain occupied today.
    We have determined that the areas occupied at the time of listing 
continue to be occupied, contain features essential to the conservation 
of the subspecies (possess one or more PCEs such that the area supports 
one or more of the Sierra Nevada bighorn sheep's life processes) that 
may require special management, and provide sufficient habitat to 
protect these populations. Units 1 (Mount Warren) and 2 (Mount Gibbs) 
of the northern recovery unit meet these criteria.
    More specifically, essential habitat is available for Sierra Nevada 
bighorn sheep in Units 1 (Mount Warren) and 2 (Mount Gibbs). This is 
not only based on historical data indicating their presence as far 
north as Sonora Pass (Grinnell and Storer 1924, as cited in Service 
2007, p. 14), but also on the fact that these units also currently 
support

[[Page 45540]]

Sierra Nevada bighorn sheep herds. Mount Warren has a population of 
approximately 26 individuals, and Mount Gibbs has a population of 
approximately 8 individuals (Wehausen and Stephenson 2006, p. 7). The 
Mount Gibbs herd spends almost the entire year at elevations above 
11,000 ft (3,353 m). In 2007, all ewes gave birth, and their lambs are 
known to have survived through at least September. This herd continues 
to survive and reproduce, expanding in numbers, although this alpine 
environment is no doubt harsher than lower-elevation areas. It is 
expected this herd will outgrow its carrying capacity of the alpine 
winter ranges and begin using lower-elevation winter ranges in the 
future (California Department of Fish and Game 2007, p. 2). Surveys 
(ground and aerial observations) of the Mount Warren herd conducted 
during the period from 2003 to 2007 indicate individuals are using this 
unit during every month of the year (California Department of Fish and 
Game files--monthly reports, Service files). In addition, a Resource 
Selection Probability Functions model was developed for summer and 
winter habitat and indicates an estimated 20.2 square kilometers (sq 
km) (7.8 square miles (sq mi)) and 9.4 sq km (3.6 sq mi), respectively, 
are available for Sierra Nevada bighorn sheep in the Mount Gibbs and 
Mount Warren units (Johnson et al. 2005, p. 31). As discussed under the 
Primary Constituent Elements for Sierra Nevada Bighorn Sheep section of 
this rule, not all life history functions require all the PCEs, 
therefore, not all areas designated as critical habitat contain all of 
the PCEs. Units are designated based on sufficient PCEs being present 
to support one or more of the subspecies' life history requirements. 
This applies to both the occupied and unoccupied units designated.
    (21) Comment: The NDOA and UNR noted that a memorandum to the 
Director of the Service from the U.S. Department of the Interior's 
Assistant Secretary for Fish and Wildlife and Parks, dated April 28, 
2004, stated that critical habitat adds little additional conservation 
benefit to a listed species and designations must not be based on 
speculation or determinations that lack supporting data. Therefore, the 
designation of critical habitat is of ``dubious value'' as identified 
by your own agency.
    Our Response: Section 4(A)(3) of the Act requires that the Service 
identify those lands on which are found the physical or biological 
features essential to the conservation of the species that may require 
special management considerations or protection, and those areas 
outside the geographical area occupied by the species at the time of 
listing that are essential to the conservation of the species. In 
identifying those lands, the Service must consider the recovery needs 
of the species, such that, on the basis of the best scientific and 
commercial data available at the time of designation, the habitat that 
is identified, if managed, could provide for the survival and recovery 
of the species.
    The identification of those areas that are essential for the 
conservation of the species and that can, if managed, provide for the 
recovery of a species is beneficial. The process of proposing and 
finalizing a critical habitat rule provides the Service with the 
opportunity to determine the physical and biological features essential 
to the conservation of the species within the geographical area 
occupied by the species at the time of listing, as well as to determine 
other areas essential for the conservation of the species. The 
designation process includes peer review and public comment on the 
identified physical and biological features and essential areas. This 
process is valuable to land owners and managers in developing 
conservation management plans for identified areas, as well as any 
other occupied habitat or suitable habitat that may not have been 
included in the Service's determination of essential habitat.
    The consultation provisions under section 7(a) of the Act 
constitute the regulatory benefits of critical habitat. As discussed 
above, Federal agencies must consult with us on discretionary actions 
that may affect critical habitat and must avoid the destruction or 
adverse modification of critical habitat. Federal agencies must also 
consult with us on discretionary actions that may affect a listed 
species and refrain from undertaking actions that are likely to 
jeopardize the continued existence of such species. The analysis of 
effects to critical habitat is a separate and different analysis from 
that of the effects to the species. Therefore, the difference in 
outcomes of these two analyses represents the regulatory benefit of 
critical habitat. For some species, and in some locations, the outcome 
of these analyses will be similar, because effects on habitat will 
often result in effects on the species. However, the regulatory 
standard is different: The jeopardy analysis looks at the action's 
impact on survival and recovery of the species, while the adverse 
modification analysis looks at the action's effects on the designated 
habitat's contribution to the species' conservation. This may, in many 
instances, lead to different results and different regulatory 
requirements. Thus, critical habitat designations may provide greater 
regulatory benefits to the recovery of a species than would listing 
alone.
    Another benefit of including lands in critical habitat is that 
designation of critical habitat serves to educate landowners, State and 
local governments, and the public regarding the potential conservation 
value of an area. In general, critical habitat designation always has 
educational benefits; however, in some cases, they may be redundant 
with other educational effects.
    (22) Comment: The NDOA states that listing of Sierra Nevada bighorn 
sheep as an endangered species, subspecies, or even distinct 
metapopulation lacks scientific merit.
    Our Response: Please refer to our final rule listing the Sierra 
Nevada bighorn sheep published on January 3, 2000 (65 FR 20), which 
outlines our rationale for listing.
    (23) Comment: The UNR stated designating critical habitat for 
Sierra Nevada bighorn sheep will lead to grazing allotment closures.
    Our Response: The designation of critical habitat for Sierra Nevada 
bighorn sheep does not automatically lead to closing allotments. For 
those areas on Federal lands, consultation under section 7 of the Act 
may be required to examine the effects of grazing on critical habitat. 
Specific actions by the managing Federal agency could include the 
elimination of, or restrictions on, livestock grazing in areas that 
overlap with critical habitat. Please also see our responses to 
Comments 24, 40, 41, and 42.
    (24) Comment: UNR states that short-term, high intensity grazing by 
domestic sheep helps maintain forage production and fuel load 
accumulation. The regrowth of vegetation is more palatable and 
nutritious for Sierra Nevada bighorn sheep during the growing season as 
well as during winter. The removal of domestic sheep will lead to 
poorer forage production and an accumulation of fuels.
    Our Response: Regardless of any effects of grazing on fuel loads 
and forage quantity and quality, domestic sheep in some locations may 
pose a disease risk to Sierra Nevada bighorn sheep. The Service will 
recommend the removal of domestic sheep from allotments where contact 
with Sierra Nevada bighorn sheep cannot be prevented through section 7 
of the Act. The Service has proposed actions in the recovery plan for 
Sierra Nevada bighorn sheep to maintain and enhance the

[[Page 45541]]

integrity of habitat through the careful use of fire and other habitat 
manipulations that do not involve domestic sheep grazing. These actions 
would include maintenance and enhancement of habitat in areas where 
domestic sheep may be removed to prevent contact with Sierra Nevada 
bighorn sheep.

Comments From Other Federal Agencies

    (25) Comment: Yosemite National Park raised a concern about any 
reduction in the proposed critical habitat and protection of the Sierra 
Nevada bighorn sheep in the ``northern recovery units'' which would 
constitute the ``Yosemite herd.'' Sierra Nevada bighorn sheep in the 
northern areas are the ones most likely to reoccupy habitat in 
Yosemite, filling an ecological void and offering park visitors the 
opportunity to observe these animals.
    Our Response: We have not reduced the area of designated critical 
habitat for the two units (Mount Warren and Mount Gibbs) that occur 
within the northern recovery unit because they meet our criteria for 
identifying critical habitat. These units contain the features 
essential to the conservation of the Sierra Nevada bighorn sheep and 
require special management. We also did not identify any areas within 
these units where the benefits of exclusion outweighed the benefits of 
inclusion. Please also see our response to Comment 20.
    (26) Comment: Yosemite National Park supports the proposed critical 
habitat designation and taxonomic revision but recommends expanding 
critical habitat to cover all areas currently occupied by Sierra Nevada 
bighorn sheep, accommodate further range expansion, and provide buffers 
between domestic sheep and Sierra Nevada bighorn sheep to prevent 
disease transmission.
    Our Response: As indicated in our response to Comment 2, it is not 
our practice to establish buffers around an area designated as critical 
habitat. A buffer distance indicated in a Federally proposed action 
involving domestic sheep or goat grazing near designated critical 
habitat would be considered during the consultation process under 
section 7 of the Act. As indicated in our response to Comment 36, 
critical habitat should not include the entire area that can be 
occupied by the species. We based our designation on the Recovery 
Team's delineation of essential habitat and as indicated in our final 
approved recovery plan (Service 2007, p. 41). For a more thorough 
discussion of these topics, please see our responses to Comments 2 and 
36.
    (27) Comment: Sequoia and Kings Canyon National Parks indicated 
their commitment to preserving and restoring natural ecosystems. They 
view Sierra Nevada bighorn sheep as an essential component that has 
been lost from much of its historical range within the Parks. By policy 
and law there is a commitment to working with the Service and other 
agencies to help restore the Sierra Nevada bighorn sheep to their 
former range and abundance. Sequoia and Kings Canyon National Parks 
fully support the proposed critical habitat designation.
    Our Response: We appreciate the support and look forward to 
continuing to work with the National Park Service and others to 
conserve the Sierra Nevada bighorn sheep.
    (28) Comment: The USFS suggested that designating critical habitat 
does not provide any additional benefit to a species and that it 
unnecessarily adds to USFS workload and may lead to re-initiation of 
section 7 consultation for critical habitat where a consultation has 
already been completed.
    Our Response: Designating critical habitat identifies those areas 
that contain the features that are essential to the conservation of a 
particular species, thus signaling to Federal agencies to consider the 
species' conservation in the design and implementation of their 
management actions. The designation provides guidance on why these 
areas need special management considerations or protection and 
indicates activities that are likely to adversely modify or destroy 
critical habitat. The designation of critical habitat assists the 
recovery process by providing information on how actions might impact 
the species' habitat. Including USFS lands as critical habitat is 
significant because this will assist in maintaining the Service's role 
in reviewing potential future impacts to areas that are important for 
the conservation of Sierra Nevada bighorn sheep populations. Lands 
administered by the USFS contain a substantial portion of habitat that 
is essential for the conservation of Sierra Nevada bighorn sheep. 
Designation of critical habitat may also provide protection for 
unoccupied habitat that may not otherwise undergo the section 7 
consultation process due to species' absence. Considering whether 
proposed future projects will result in the destruction or adverse 
modification of critical habitat in addition to the jeopardy analysis 
will require some additional analysis during the section 7 consultation 
process.
    (29) Comment: The USFS indicated the 2001 Record of Decision for 
the Ansel Adams, John Muir, and Dinky Lakes Wilderness Plans considered 
various impacts on Sierra Nevada bighorn sheep and their habitats.
    Our Response: We appreciate this information and have reviewed this 
document. Only one item was found directly related to management of the 
Sierra Nevada bighorn sheep. This addressed the closure of Sierra 
Nevada bighorn sheep habitat to dogs. As indicated in the Special 
Management Considerations or Protection section, dogs (with their 
associated recreation activities) are a potential threat to Sierra 
Nevada bighorn sheep critical habitat. At issue are the effects of 
Wilderness Plans, associated Forest Land and Resource Management Plans, 
and ongoing activities on USFS lands on federally listed species, 
including the Sierra Nevada bighorn sheep. The goal of these plans is 
to describe a strategic direction for the management of the wilderness 
areas over a long period of time (15-20 years). The plans do not make 
any decisions regarding USFS site-specific project proposals for 
implementing the land management plans nor do they require managers to 
implement any specific conservation activities.
    (30) Comment: The USFS stated that management direction was 
established to restrict dogs in Sierra Nevada bighorn sheep habitat 
located in the Mt. Baxter and Mt. Williamson California Bighorn Sheep 
Zoological Areas on the Inyo National Forest.
    Our Response: Please see our response to Comment 29. These 
statements also apply to FS Order No. 04-81-3 which established these 
zoological areas in 1981.
    (31) Comment: The USFS commented that the proposed critical habitat 
designation does not establish migration corridors between the units 
though migration is identified as important. While paths that rams may 
take between units or groups may be unpredictable, the final 
designation would be strengthened if it were to identify dispersal and 
movement corridors that are integral to the habitat elements.
    Our Response: Please see our response to Comment 4.
    (32) Comment: The USFS requests clarification on why disease 
transmission from domestic livestock grazing is included as a 
stochastic event.
    Our Response: This has been corrected. We have removed those 
references specifically identifying the risk of disease transmission 
from domestic livestock from (3) of the Criteria Used To Identify 
Critical

[[Page 45542]]

Habitat section. The remaining reference addresses various diseases of 
North American wild sheep.
    (33) Comment: The USFS suggested that the proposal is not as clear 
as it should be regarding the effects of disease transmission on Sierra 
Nevada bighorn sheep populations. Incorporating disease-associated 
risks into a PCE would strengthen the proposal.
    Our Response: We have added some additional information in the 
biological background of the Primary Constituent Elements section of 
this rule. Please also see our response to Comment 1.
    (34) Comment: The USFS stated that while it is important to 
decrease the degree of habitat fragmentation in the Sierra Nevada, the 
designation of critical habitat does not actually do that.
    Our Response: Designation of critical habitat offers protection 
from various impacts which may be proposed on the landscape. We believe 
designating critical habitat in 12 units ranging from 22,037 ac (8,918 
ha) to 80,966 ac (32,766 ha) does reduce potential habitat 
fragmentation. Providing protections for currently unoccupied areas 
that decrease the distances between occupied areas also assists in 
reducing habitat fragmentation. The protection of these unoccupied 
habitats will allow for future establishment of herds in these habitats 
through translocation or natural colonization, which will help to 
increase gene flow between populations. The ability to establish and 
maintain regular gene flow between populations of Sierra Nevada bighorn 
sheep is essential to their recovery. Reducing habitat fragmentation 
through protection of these currently unoccupied habitats under a 
critical habitat designation is essential to the subspecies' 
conservation.
    (35) Comment: The USFS recommended that the section discussing 
wildfire be clarified to resolve apparent contradictions identifying 
which management actions and stochastic events are considered 
potentially beneficial or detrimental to critical habitat.
    Our Response: Fires can have beneficial, as well as detrimental, 
effects depending on the situation including location, severity, and 
extent. As indicated in the Special Management Considerations or 
Protection section, management actions such as the suppression of 
wildfires over the past decades has allowed for encroachment of 
forested habitat into Sierra Nevada bighorn sheep habitat. This has 
been detrimental to the Sierra Nevada bighorn sheep by increasing 
habitat for predator concealment. Management actions such as prescribed 
fires are carried out in a planned, controlled manner in a specific 
area and can be beneficial to Sierra Nevada bighorn sheep by reducing 
selected forested habitat that can conceal predators. Stochastic events 
such as wildfires can be beneficial or detrimental. For example, in 
July 2007, lightning sparked fires in Sierra Nevada bighorn sheep 
habitat in the Mount Baxter herd unit. The Seven Oaks Fire burned the 
majority of the low elevation winter range [<8,000 ft (2438 m)] 
(California Department of Fish and Game 2007, p. 5). The fire may 
benefit Sierrra Nevada bighorn sheep by opening up forested areas. The 
fire also scorched the above ground vegetation. With appropriate 
moisture levels gained over the winter, sufficient forage may become 
available. The CDFG personnel intend to evaluate the effects of this 
fire on forage availability and quality and habitat selection by Sierra 
Nevada bighorn sheep in this area (California Department of Fish and 
Game 2007, p. 6).
    (36) Comment: The USFS mentioned that the Mount Warren unit may not 
extend northward enough to encompass currently occupied habitat as a 
few Sierra Nevada bighorn sheep have occurred in the northern areas.
    Our Response: According to 16 U.S.C. 1532(5)(C), ``critical habitat 
should not include the entire geographic area that can be occupied by 
the threatened or endangered species'' absent a finding of exceptional 
circumstances by the Secretary of the Interior. We based our critical 
habitat designation on the Recovery Team's delineation of essential 
habitat and as indicated in our final approved recovery plan (Service 
2007, p