Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Contiguous United States Distinct Population Segment of the Canada Lynx (Lynx canadensis), 10860-10896 [08-779]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 40 (Thursday, February 28, 2008)]
[Proposed Rules]
[Pages 10860-10896]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 08-779]



[[Page 10859]]

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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 Critical Habitat 
for the Contiguous United States Distinct Population Segment of the 
Canada Lynx (Lynx canadensis); Proposed Rule

Federal Register / Vol. 73, No. 40 / Thursday, February 28, 2008 / 
Proposed Rules

[[Page 10860]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R6-ES-2008-0026]
92210-1117-0000-B4]
RIN 1018-AV78


Endangered and Threatened Wildlife and Plants; Revised Critical 
Habitat for the Contiguous United States Distinct Population Segment of 
the Canada Lynx (Lynx canadensis)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
revise designated critical habitat for the contiguous United States 
distinct population segment of the Canada lynx (Lynx canadensis) (lynx) 
under the Endangered Species Act of 1973, as amended (Act). In the 
contiguous United States, the lynx generally inhabits cold, moist 
boreal forests. Approximately 42,753 square miles (mi\2\) (110,727 
square kilometers (km\2\)) fall within the boundaries of the proposed 
revised critical habitat designation. The proposed revised designation 
would add an additional 40,913 mi\2\ (105,959 km\2\) to the existing 
critical habitat designation of 1,841 mi\2\ (4,768 km\2\). The proposed 
revised critical habitat is located in Boundary County, Idaho; 
Aroostook, Franklin, Penobscot, Piscataquis, and Somerset Counties in 
Maine; Cook, Koochiching, Lake, and St. Louis Counties in Minnesota; 
Flathead, Glacier, Granite, Lake, Lewis and Clark, Lincoln, Missoula, 
Pondera, Powell, Teton, Gallatin, Park, Sweetgrass, Stillwater, and 
Carbon Counties in Montana; Chelan and Okanogan Counties in Washington; 
and Park, Teton, Fremont, Sublette, and Lincoln Counties in Wyoming.

DATES: We will accept comments received or postmarked on or before 
April 28, 2008. We must receive requests for public hearings, in 
writing, at the address shown in the ADDRESSES section by April 14, 
2008.

ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: [FWS-R6-ES-2008-0026]; Division of Policy and Directives 
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, 
Suite 222; Arlington, VA 22203.
    We will not accept e-mail or faxed comments. We will post all 
comments on https://www.regulations.gov. This generally means that we 
will post any personal information you provide us (see the Public 
Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: Mark Wilson, Field Supervisor, Montana 
Ecological Services Office, 585 Shepard Way, Helena, MT, 59601; 
telephone 406-449-5225. If you use a telecommunications device for the 
deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION: 

Public Comments

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, we request 
comments or suggestions on this proposed rule. We particularly seek 
comments concerning:
    (1) The reasons why we should or should not designate specific 
habitat as ``critical habitat'' under section 4 of the Act (16 U.S.C. 
1531 et seq.).
    (2) Specific information on:
     The amount and distribution of lynx habitat,
     What areas occupied at the time of listing and that 
contain features essential for the conservation of the species we 
should include in the designation and why that might be so, and
     What areas not occupied at the time of listing are 
essential to the conservation of the species and why that might be so.
    (3) Comments or information that may assist us with identifying or 
clarifying the primary constituent element.
    (4) Land use designations and current or planned activities in the 
areas proposed as critical habitat and their possible impacts on 
proposed revised critical habitat.
    (5) Whether Tribal lands in the Northern Rockies, Maine, and 
Minnesota units need to be included as critical habitat pursuant to 
Secretarial Order Number 3206.
    (6) Whether lands the Southern Rocky Mountains contain the physical 
and biological features that are essential for the conservation of the 
species and the basis for why that might be so
    (7) Whether lands in any unoccupied areas, such as the ``Kettle 
Range'' in Ferry County, Washington, are essential to the conservation 
of lynx and the basis for why that might be so.
    (8) How the proposed boundaries of the revised critical habitat 
could be refined to more closely circumscribe the boreal forest 
landscapes occupied by lynx. Refined maps that accurately depict the 
specific vegetation types on all land ownerships are not readily 
available. We are especially interested in this information for the 
Greater Yellowstone Area unit.
    (9) Whether our proposed revised critical habitat for the lynx 
should be altered in any way to account for climate change.
    (10) Whether the proposed revised critical habitat designation for 
the lynx should include private lands, or whether the proposed Federal 
lands are sufficient to conserve lynx.
    (11) Whether U.S. Forest Service (USFS) lands that occur in the 
wildland-urban-interface (WUI) should be excluded from critical habitat 
under section 4(b)(2) of the Act so that fuels-reduction projects 
designed to protect human life and property from wildfire would not be 
impeded in any way in these areas.
    (12) Whether the Greater Yellowstone Area is essential to the 
conservation of lynx. Lynx in this proposed unit occur at lower 
densities than in other proposed units, and the population is not 
connected to Canada, which is an important source of lynx in the United 
States.
    (13) Any foreseeable economic, national security, or other 
potential impacts resulting from the proposed designation and, in 
particular, any impacts on small entities, and the benefits of 
including or excluding areas that exhibit these impacts.
    (14) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    The size of the individual Indian reservation lands in the Northern 
Rockies, Maine, and Minnesota units is relatively small. As a result, 
we believe conservation of the lynx can be achieved by limiting the 
designation to the other lands in the proposal without including Tribal 
lands (see ``Relationship of Critical Habitat to Tribal Lands'' below).
    The southern Rocky Mountains in Colorado, Utah, and southern 
Wyoming are disjunct from other lynx habitats in the United States and 
Canada. The nearest lynx population occurs in the Greater Yellowstone 
Area (GYA), which is a small, low density population also disjunct from 
other lynx populations and is unlikely to regularly supply dispersing 
lynx to the Southern Rockies. Native lynx were functionally extirpated

[[Page 10861]]

from their historic range in Colorado and southern Wyoming by the time 
the lynx was listed as a threatened species under the Act in 2000. In 
1999, the State of Colorado began an intensive effort to reintroduce 
lynx. Although it is too early to determine whether the introduction 
will result in a self-sustaining population, the reintroduced lynx have 
produced kittens and now are distributed throughout the lynx habitat in 
Colorado and southern Wyoming. These animals are not designated as an 
experimental population under section 10(j) of the Act. Although 
Colorado's reintroduction effort is an important step toward the 
recovery of lynx, we are not proposing revised critical habitat in the 
Southern Rockies because of the current uncertainty that a self-
sustaining lynx population will become established.
    The Kettle Range in Washington historically supported lynx 
populations (Stinson 2001). However, although boreal forest habitat 
within the Kettle Range appears of high quality for lynx, there is no 
evidence that the Kettle Range is currently occupied by a lynx 
population nor has there been evidence of reproducing lynx in the 
Kettle Range in the past two decades (Koehler 2008).
    Fuels-reduction projects in the WUI may degrade lynx habitat by 
reducing its ability to support snowshoe hares. For this reason, if WUI 
areas were designated as revised critical habitat, fuels-reduction 
projects may be impaired or delayed as a result of requirements under 
section 7(a)(2) of the Act, which could lead to reduced effectiveness 
of the fuels-reduction, and increased risk to human life and property. 
Mapped WUI areas can be viewed on the Internet at: ftp://
ftp2.fs.fed.us/incoming/r1/FWS/wui_1mile_buffer_oct06.pdf.
    In addition to public comments received on this proposed rule, 
between the proposed and final rules, the Service will analyze the 
following for its relevance in revising critical habitat for lynx: (1) 
Comments received in response to our initiation of a 5-year review for 
lynx; (2) a new study addressing effects of snowmobile trails on coyote 
movements within lynx home ranges (Kolbe et al. 2007, pp. 1409-1418); 
(3) a study on lynx prey selection (Squires and Ruggiero 2007, pp. 310-
315); (4) new reports we have received on the numbers and distribution 
of lynx in some locations; (5) a newly released study on the effects of 
climate change on snowpack in western mountains and how that may affect 
lynx, snowshoe hares, and their habitats (Gonzalez et al. 2007); and 
(6) additional new studies (e.g., Knowles et al. 2006 and Danby and 
Hick 2007) that may provide insight on changes to lynx habitat. If 
necessary and appropriate, revisions to this proposed rule will be made 
to address this information. We will also be revising the economic 
analysis and environmental assessment prepared for the previous 
designation and providing drafts of the new economic analysis and 
environmental assessment to the public before finalizing this proposal.
    On the basis of public comment, during the development of the 
revised final rule we may find, among other things, that areas proposed 
are not essential to the conservation of the species, are appropriate 
for exclusion under section 4(b)(2) of the Act, or are not appropriate 
for exclusion. In all of these cases, this information will be 
incorporated into the revised final designation. Further, we may find 
as a result of public comments that areas not proposed should also be 
designated as critical habitat. Final management plans that address the 
conservation of the lynx must be submitted to us during the public 
comment period so that we can take them into consideration when making 
our final critical habitat determination.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
accept comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section. We will not accept anonymous comments; your 
comment must include your first and last name, city, State, country, 
and postal (zip) code. Finally, we will not consider hand-delivered 
comments that we do not receive, or mailed comments that are not 
postmarked, by the date specified in the DATES section.
    We will post your entire comment--including your personal 
identifying information--on https://www.regulations.gov. If you provide 
personal identifying information in addition to the required items 
specified in the previous paragraph, such as your street address, phone 
number, or e-mail address, you may request at the top of your document 
that we withhold this information from public review. However, we 
cannot guarantee that we will be able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this revised proposed rule, will be 
available for public inspection on https://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Montana Ecological Services Office (see FOR FURTHER 
INFORMATION CONTACT). Maps of the proposed revised critical habitat are 
also available on the Internet at https://mountain-prairie.fws.gov/
species/mammals/lynx/.

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat in this proposed rule. For more 
information on the lynx refer to the final listing rule published in 
the Federal Register on March 24, 2000 (65 FR 16052), and the 
clarification of findings published in the Federal Register on July 3, 
2003 (68 FR 40076).
    Canada lynx are medium-sized cats, generally measuring 30 to 35 
inches (in) (75 to 90 centimeters (cm)) long and weighing 18 to 23 
pounds (8 to 10.5 kilograms) (Quinn and Parker 1987, Table 1). They 
have large, well-furred feet and long legs for traversing snow; tufts 
on the ears; and short, black-tipped tails.
    Lynx are highly specialized predators of snowshoe hare (Lepus 
americanus) (McCord and Cardoza 1982, p. 744; Quinn and Parker 1987, 
pp. 684-685; Aubry et al. 2000, pp. 375-378). Lynx and snowshoe hares 
are strongly associated with what is broadly described as boreal forest 
(Bittner and Rongstad 1982, p. 154; McCord and Cardoza 1982, p. 743; 
Quinn and Parker 1987, p. 684; Agee 2000, p. 39; Aubry et al. 2000, pp. 
378-382; Hodges 2000a, pp. 136-140 and 2000b, pp. 183-191; McKelvey et 
al. 2000b, pp. 211-232). The predominant vegetation of boreal forest is 
conifer trees, primarily species of spruce (Picea spp.) and fir (Abies 
spp.) (Elliot-Fisk 1988, pp. 34-35, 37-42). In the contiguous United 
States, the boreal forest types transition to deciduous temperate 
forest in the Northeast and Great Lakes and to subalpine forest in the 
west (Agee 2000, pp. 40-41). Lynx habitat can generally be described as 
moist boreal forests that have cold, snowy winters and a snowshoe hare 
prey base (Quinn and Parker 1987, p. 684-685; Agee 2000, pp. 39-47; 
Aubry et al. 2000, pp. 373-375; Buskirk et al. 2000b, pp. 397-405; 
Ruggiero et al. 2000, pp. 445-447). In mountainous areas, the boreal 
forests that lynx use are characterized by scattered moist forest types 
with high hare densities in a matrix of other habitats (e.g., 
hardwoods, dry forest, non-forest) with low hare densities. In these 
areas, lynx incorporate the matrix habitat (non-boreal forest habitat 
elements) into their home ranges and use it for traveling between 
patches of boreal forest that support high hare densities where most 
foraging occurs.

[[Page 10862]]

    Snow conditions also determine the distribution of lynx (Ruggiero 
et al. 2000, pp. 445-449). Lynx are morphologically and physiologically 
adapted for hunting snowshoe hares and surviving in areas that have 
cold winters with deep, fluffy snow for extended periods. These 
adaptations provide lynx a competitive advantage over potential 
competitors, such as bobcats (Lynx rufus) or coyotes (Canis latrans) 
(McCord and Cardoza 1982, p. 748; Buskirk et al. 2000a, pp. 86-95; 
Ruediger et al. 2000, p. 1-11; Ruggiero et al. 2000, pp. 445, 450). 
Bobcats and coyotes have a higher foot load (more weight per surface 
area of foot), which causes them to sink into the snow more than lynx. 
Therefore, bobcats and coyotes cannot efficiently hunt in fluffy or 
deep snow and are at a competitive disadvantage to lynx. Long-term snow 
conditions presumably limit the winter distribution of potential lynx 
competitors such as bobcats (McCord and Cardoza 1982, p. 748) or 
coyotes.

Lynx Habitat Requirements

    Because of the patchiness and temporal nature of high quality 
snowshoe hare habitat, lynx populations require large boreal forest 
landscapes to ensure that sufficient high quality snowshoe hare habitat 
is available and to ensure that lynx may move freely among patches of 
suitable habitat and among subpopulations of lynx. Populations that are 
composed of a number of discrete subpopulations, connected by 
dispersal, are called metapopulations (McKelvey et al. 2000c, p. 25). 
Individual lynx maintain large home ranges (reported as generally 
ranging between 12 to 83 mi\2\ (31 to 216 km\2\)) (Koehler 1990, p. 
847; Aubry et al. 2000, pp. 382-386; Squires and Laurion 2000, pp. 342-
347; Squires et al. 2004b, pp. 13-16, Table 6; Vashon et al. 2005a, pp. 
7-11). The size of lynx home ranges varies depending on abundance of 
prey, the animal's gender and age, the season, and the density of lynx 
populations (Koehler 1990, p. 849; Poole 1994, pp. 612-616; Slough and 
Mowat 1996, pp. 951, 956; Aubry et al. 2000, pp. 382-386; Mowat et al. 
2000, pp. 276-280; Vashon et al. 2005a, pp. 9-10). When densities of 
snowshoe hares decline, for example, lynx enlarge their home ranges to 
obtain sufficient amounts of food to survive and reproduce.
    In the contiguous United States, the boreal forest landscape is 
naturally patchy and transitional because it is the southern edge of 
the boreal forest range. This generally limits snowshoe hare 
populations in the contiguous United States from achieving densities 
similar to those of the expansive northern boreal forest in Canada 
(Wolff 1980, pp. 123-128; Buehler and Keith 1982, pp. 24, 28; Koehler 
1990, p. 849; Koehler and Aubry 1994, p. 84). Additionally, the 
presence of more snowshoe hare predators and competitors at southern 
latitudes may inhibit the potential for high-density hare populations 
(Wolff 1980, p. 128). As a result, lynx generally occur at relatively 
low densities in the contiguous United States compared to the high lynx 
densities that occur in the northern boreal forest of Canada (Aubry et 
al. 2000, pp. 375, 393-394) or the densities of species such as the 
bobcat, which is a habitat and prey generalist.
    Lynx are highly mobile and generally move long distances (greater 
than 60 mi (100 km)) (Aubry et al. 2000, pp. 386-387; Mowat et al. 
2000, pp. 290-294). Lynx disperse primarily when snowshoe hare 
populations decline (Ward and Krebs 1985, pp. 2821-2823; O'Donoghue et 
al. 1997, pp. 156, 159; Poole 1997, pp. 499-503). Subadult lynx 
disperse even when prey is abundant (Poole 1997, pp. 502-503), 
presumably to establish new home ranges. Lynx also make exploratory 
movements outside their home ranges (Aubry et al. 2000, p. 386; Squires 
et al. 2001, pp. 18-26).
    The boreal forest landscape is naturally dynamic. Forest stands 
within the landscape change as they undergo succession after natural or 
human-caused disturbances such as fire, insect epidemics, wind, ice, 
disease, and forest management (Elliot-Fisk 1988, pp. 47-48; Agee 2000, 
pp. 47-69). As a result, lynx habitat within the boreal forest 
landscape is typically patchy because the boreal forest contains stands 
of differing ages and conditions, some of which are suitable as lynx 
foraging or denning habitat (or will become suitable in the future due 
to forest succession) and some of which serve as travel routes for lynx 
moving between foraging and denning habitat (McKelvey et al. 2000a, pp. 
427-434; Hoving et al. 2004, pp. 290-292).
    Snowshoe hares comprise a majority of the lynx diet (Nellis et al. 
1972, pp. 323-325; Brand et al. 1976, pp. 422-425; Koehler 1990, p. 
848; Apps 2000, pp. 358-359, 363; Aubry et al. 2000, pp. 375-378; Mowat 
et al. 2000, pp. 267-268; von Kienast 2003, pp. 37-38; Squires et al. 
2004b, p. 15, Table 8). When snowshoe hare populations are low, female 
lynx produce few or no kittens that survive to independence (Nellis et 
al. 1972, pp. 326-328; Brand et al. 1976, pp. 420, 427; Brand and Keith 
1979, pp. 837-838, 847; Poole 1994, pp. 612-616; Slough and Mowat 1996, 
pp. 953-958; O'Donoghue et al. 1997, pp. 158-159; Aubry et al. 2000, 
pp. 388-389; Mowat et al. 2000, pp. 285-287). Lynx prey 
opportunistically on other small mammals and birds, particularly during 
lows in snowshoe hare populations, but alternate prey species may not 
sufficiently compensate for low availability of snowshoe hares, 
resulting in reduced lynx populations (Brand et al. 1976, pp. 422-425; 
Brand and Keith 1979, pp. 833-834; Koehler 1990, pp. 848-849; Mowat et 
al. 2000, pp. 267-268).
    In northern Canada, lynx populations fluctuate in response to the 
cycling of snowshoe hare populations (Hodges 2000a, pp. 118-123; Mowat 
et al. 2000, pp. 270-272). Although snowshoe hare populations in the 
northern portion of their range show strong, regular population cycles, 
these fluctuations are generally much less pronounced in the southern 
portion of their range in the contiguous United States (Hodges 2000b, 
pp. 165-173). In the contiguous United States, the degree to which 
regional local lynx population fluctuations are influenced by local 
snowshoe hare population dynamics is unclear. However, it is 
anticipated that because of natural fluctuations in snowshoe hare 
populations, there will be periods when lynx densities are extremely 
low.
    Because lynx population dynamics, survival, and reproduction are 
closely tied to snowshoe hare availability, snowshoe hare habitat is a 
component of lynx habitat. Lynx generally concentrate their foraging 
and hunting activities in areas where snowshoe hare populations are 
high (Koehler et al. 1979, p. 442; Ward and Krebs 1985, pp. 2821-2823; 
Murray et al. 1994, p. 1450; O'Donoghue et al. 1997, pp. 155, 159-160 
and 1998, pp. 178-181). Snowshoe hares are most abundant in forests 
with dense understories that provide forage, cover to escape from 
predators, and protection during extreme weather (Wolfe et al. 1982, 
pp. 665-669; Litvaitis et al. 1985, pp. 869-872; Hodges 2000a, pp. 136-
140 and 2000b, pp. 183-195). Generally, hare densities are higher in 
regenerating, earlier successional forest stages because they have 
greater understory structure than mature forests (Buehler and Keith 
1982, p. 24; Wolfe et al. 1982, pp. 665-669; Koehler 1990, pp. 847-848; 
Hodges 2000b, pp. 183-195; Homyack 2003, p. 63, 141; Griffin 2004, pp. 
84-88). However, snowshoe hares can be abundant in mature forests with 
dense understories (Griffin 2004, pp. 53-54).
    Within the boreal forest, lynx den sites are located where coarse 
woody debris, such as downed logs and windfalls, provides security and 
thermal cover for lynx kittens (McCord and Cardoza 1982, pp. 743-744; 
Koehler

[[Page 10863]]

1990, pp. 847-849; Slough 1999, p. 607; Squires and Laurion 2000, pp. 
346-347; Organ 2001). The amount of structure (e.g., downed, large, 
woody debris) appears to be more important than the age of the forest 
stand for lynx denning habitat (Mowat et al. 2000, pp. 10-11).

Future of Lynx Habitat

    In 2003, we determined that climate change was not a threat to lynx 
because the best available science we had at that time (Hoving 2001) 
was too uncertain in nature (68 FR 40083). Since that time, new 
information on regional climate changes and potential effects to lynx 
habitat has been developed (e.g., Gonzalez et al. 2007, entire; Knowles 
et al. 2006, pp. 4545-4559; Danby and Hick 2007, pp. 358-359) that 
suggests that climate change may be an issue of concern for the future 
conservation of lynx. This information, combined with the information 
in Hoving 2001, still needs to be evaluated further to determine how 
climate change might affect lynx and lynx habitat. We are evaluating 
this information in the 5-year review we are conducting for lynx.
    At this time, we find it appropriate to propose revised critical 
habitat in areas that are occupied and currently contain the physical 
and biological features essential to the conservation of the lynx. 
Revisions to the critical habitat designation may be necessary in the 
future to accommodate shifts in the occupied range of the lynx. To the 
extent lynx distribution and habitat is likely to shift upward in 
elevation within its currently occupied range as the temperatures 
increase (Gonzalez et al. 2007, pp. 7, 13-14,19), the proposed revised 
critical habitat units include the highest-elevation habitats that lynx 
would be able to use in that event.

Previous Federal Actions

    For more information on previous Federal actions concerning the 
lynx, refer to the final listing rule published in the Federal Register 
on March 24, 2000 (65 FR 16052), the clarification of findings 
published in the Federal Register on July 3, 2003 (68 FR 40076), and 
the final rule designating critical habitat for lynx published in the 
Federal Register on November 9, 2006 (71 FR 66007). On July 20, 2007, 
the Service announced that we would review the November 9, 2006 final 
rule after questions were raised about the integrity of scientific 
information used and whether the decision made was consistent with the 
appropriate legal standards. Based on our review of the previous final 
critical habitat designation, we have determined that it is necessary 
to revise critical habitat, and this rule proposes those revisions. On 
January 15, 2008, the U.S. District Court for the District of Columbia 
issued an order stating the Service's deadlines for a proposed rule for 
revised critical habitat by February 15, 2008, and a final rule for 
revised critical habitat by February 15, 2009.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by a 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species and
    (b) That may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by a 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means the use 
of all methods and procedures that are necessary to bring any 
endangered species or threatened species to the point at which the 
measures provided under the Act are no longer necessary.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against Federal agencies carrying out, funding, 
or authorizing activities that result in the destruction or adverse 
modification of critical habitat. Section 7 of the Act requires 
consultation on Federal actions that may affect critical habitat. The 
designation of critical habitat does not affect land ownership or 
establish a refuge, wilderness, reserve, preserve, or other 
conservation area. Such designation does not allow the government or 
public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by the 
landowner. Where the landowner seeks or requests Federal agency funding 
or authorization of an activity that may affect a listed species or 
critical habitat, the consultation requirements of section 7 would 
apply. Nonetheless, even in the event a project with a Federal nexus 
may result in the destruction or adverse modification of critical 
habitat, the landowner's obligation is not to restore or recover the 
species, but to implement reasonable and prudent alternatives to avoid 
destruction or adverse modification of critical habitat.
    For inclusion in a critical habitat designation, habitat within the 
geographical area occupied by the species at the time it was listed 
must contain physical and biological features that are essential to the 
conservation of the species. Consistent with this requirement, the 
Service identifies, to the extent known using the best scientific data 
available, habitat areas on which are found the physical and biological 
features essential, as defined at 50 CFR 424.12(b), and identifies the 
quantity and spatial arrangement of such areas to ensure that the areas 
designated as critical habitat are essential for the conservation of 
the species. Occupied habitat that contains the physical and biological 
features essential to the conservation of the species meets the 
definition of critical habitat only if those features may require 
special management considerations or protection.
    Under the Act, we can designate unoccupied areas as critical 
habitat only when we determine that the best available scientific data 
demonstrate that the designation of that area is essential to the 
conservation of the species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards Under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
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. 
These documents require our biologists, to the extent consistent with 
the Act and with the use of the best scientific data available, to use 
primary and original sources of information as the basis for 
recommendations to designate critical habitat.
    When we are determining which areas should be proposed as critical 
habitat, our primary source of information is generally the information 
developed during the listing process for the species. Additional 
information sources may 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.

[[Page 10864]]

    Habitat is often dynamic, and species may move from one area to 
another over time. Furthermore, we recognize that designation of 
critical habitat may not include all of the habitat areas that we may 
eventually determine, based on scientific data not now available to the 
Service, are necessary for the recovery of the species. For these 
reasons, a critical habitat designation does not signal that habitat 
outside the designated area is unimportant or may not be required for 
recovery of the species.
    Areas that support populations, but are outside the critical 
habitat designation, may continue to be subject to conservation actions 
we implement under section 7(a)(1) of the Act. They are also subject to 
the regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available scientific 
information at the time of the agency action. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may still result in jeopardy findings in some 
cases. Similarly, critical habitat designations made on the basis of 
the best available information at the time of designation will not 
control the direction and substance of future recovery plans, habitat 
conservation plans (HCPs), section 7 consultation, or other species 
conservation planning efforts if new information calls for a different 
outcome.

Methods

    As required by section 4(b)(2) of the Act, we use the best 
scientific data available to determine areas occupied at the time of 
listing that contain the features essential to the conservation of the 
lynx. We have reviewed the approach to the conservation of the lynx 
provided in its recovery outline (Service 2005, entire) and information 
from State, Federal, and Tribal agencies, and from academia and private 
organizations that have collected scientific data on lynx. The Service 
also obtained information about critical habitat for lynx in 2005 and 
2006 during development of rules for lynx critical habitat. The Service 
also initiated a 5-year review for the lynx on April 18, 2007 (72 FR 
19549). Information gathered for that purpose will be used in 
completing our final designation.
    We have used information we reviewed for the prior designation of 
critical habitat, including data in reports submitted by researchers 
holding recovery permits under section 10(a)(1)(A) of the Act, research 
published in peer-reviewed articles and presented in academic theses, 
agency reports, unpublished data, and various Geographic Information 
System (GIS) data layers (e.g., land cover type information, land 
ownership information, snow depth information, topographic information, 
locations of lynx obtained from radio- or Global Positioning System 
(GPS) collars, and locations of lynx confirmed via deoxyribonucleic 
acid (DNA) analysis or other verified records).

Primary Constituent Elements

    In accordance with section 3(5)(A)(i) of the Act and the 
regulations at 50 CFR 424.12(b), in determining which areas occupied at 
the time of listing to propose as critical habitat, we consider the 
physical and biological features that are essential to the conservation 
of the species to be the primary constituent elements (PCEs) laid out 
in the appropriate quantity and spatial arrangement for conservation of 
the species. In general, PCEs include, but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historic, geographical, and ecological 
distributions of a species.
    When considering the designation of critical habitat, we must focus 
on the principal biological or physical constituent elements within the 
defined area that are essential to the conservation of the species. As 
previously stated, we consider the physical and biological features 
that are essential to the conservation of the species to be the primary 
constituent elements (PCEs) laid out in the appropriate quantity and 
spatial arrangement for conservation of the species. As such, we derive 
the PCEs required for lynx from its biological needs. The area proposed 
for designation as revised critical habitat provides boreal forest 
habitat for breeding, non-breeding, and dispersing lynx in 
metapopulations across their range in the contiguous United States. We 
are not proposing any areas solely because they provide habitat for 
dispersing animals because the areas we are proposing serve a variety 
of functions that include acting as a source of dispersing animals and 
providing habitat that serves as travel corridors to facilitate 
dispersal and exploratory movements. The primary constituent elements 
and therefore the resulting physical and biological features essential 
for the conservation of the species were determined from studies of 
lynx and snowshoe hare ecology.

Space for Individual and Population Growth and Normal Behavior--Boreal 
Forest Landscapes

    Lynx populations respond to biotic and abiotic factors at different 
scales. At the regional scale, snow conditions, boreal forest, and 
competitors (especially bobcat) influence the species' range (Aubry et 
al. 2000, pp. 378-380; McKelvey et al. 2000b, pp. 242-253; Hoving et 
al. 2005, p. 749). At the landscape scale within each region, natural 
and human-caused disturbance processes (e.g., fire, wind, insect 
infestations, and forest management) influence the spatial and temporal 
distribution of lynx populations by affecting the distribution of good 
habitat for snowshoe hares (Agee 2000, pp. 47-73; Ruediger et al. 2000, 
pp. 1-3, 2-2, 2-6, 7-3). At the stand-level scale, quality, quantity, 
and juxtaposition of habitats influence home range size, productivity, 
and survival (Aubry et al. 2000, pp. 380-390; Vashon et al. 2005a, pp. 
9-11). At the substand scale, spatial distribution, abundance of prey, 
and microclimate influence movements, hunting behavior, and den and 
resting site locations.
    All of the components of the physical and biological features of 
proposed revised critical habitat for lynx are found within large 
landscapes in what is broadly described as the boreal forest or cold 
temperate forest (Frelich and Reich 1995, p. 325; Agee 2000, pp. 43-
46). The primary constituent element is broadly described as the boreal 
forest landscape. In the contiguous United States, the boreal forest is 
more transitional than the true boreal forest of northern Canada and 
Alaska (Agee 2000, pp. 43-46). This difference is because the boreal 
forest is at its southern limits in the contiguous United States, where 
it transitions to deciduous temperate forest in the Northeast and Great 
Lakes and subalpine forest in the west (Agee 2000, pp. 43-46). We use 
the term ``boreal forest'' because it generally encompasses most of the 
vegetative descriptions of the transitional forest types that comprise 
lynx habitat in the contiguous United States (Agee 2000, pp. 40-41).
    At a regional scale, lynx habitat exists in areas that generally 
support deep snow throughout the winter and boreal forest vegetation 
types (see below for more detail). In eastern North America,

[[Page 10865]]

lynx distribution is strongly associated with areas of deep snowfall 
(greater than 105 in (268 cm) of mean annual snowfall) and 40 mi\2\ 
(100 km\2\) landscapes with a high proportion of regenerating forest 
(Hoving 2001, pp. 75, 143). The broad geographic distribution of lynx 
in eastern North America is most influenced by snowfall, but within 
areas of similarly deep snowfall, measures of forest succession become 
more important factors in determining lynx distribution (Hoving et al. 
2004, p. 291).
    Boreal forests used by lynx are cool, moist, and dominated by 
conifer tree species, primarily spruce and fir (Agee 2000, pp. 40-46; 
Aubry et al. 2000, pp. 378-383; Ruediger et al. 2000, pp. 4-3, 4-8, 4-
11, 4-25, 4-26, 4-29, 4-30). Boreal forest landscapes used by lynx are 
a heterogeneous mosaic of vegetative cover types and successional 
forest stages created by natural and human-caused disturbances 
(McKelvey et al. 2000a, pp. 426, 434). Periodic vegetation disturbances 
stimulate development of dense understory or early successional habitat 
for snowshoe hares (Ruediger et al. 2000, pp. 1-3, 1-4, 7-4, 7-5). In 
Maine, lynx were positively associated with landscapes clearcut 15 to 
25 years previously (Hoving et al. 2004, p. 291).
    The overall quality of the boreal forest landscape matrix and the 
juxtaposition of stands in suitable condition within that landscape is 
important for both lynx and snowshoe hares in that it influences 
connectivity or movements between suitable stands, availability of food 
and cover, and spatial structuring of populations or subpopulations 
(Hodges 2000b, pp. 181-195; McKelvey et al. 2000a, pp. 431-432; Walker 
2005, p. 79). For example, lynx foraging habitat must be near denning 
habitat to allow females to adequately provide for dependent kittens, 
especially when the kittens are relatively immobile. In north-central 
Washington, hare densities were higher in landscapes with an abundance 
of dense boreal forest interspersed with small patches of open habitat, 
in contrast to landscapes composed primarily of open forest 
interspersed with few dense vegetation patches (Walker 2005, p. 79). 
Similarly, in northwest Montana, connectivity of dense patches within 
the forest matrix benefited snowshoe hares (Ausband and Baty 2005, p. 
209). In mountainous areas, lynx appear to prefer flatter slopes (Apps 
2000, p. 361; McKelvey et al. 2000d, p. 333; von Kienast 2003, p. 21, 
Table 2; Maletzke 2004, pp. 17-18).
    Individual lynx require large portions of boreal forest landscapes 
to support their home ranges and to facilitate dispersal and 
exploratory travel. The size of lynx home ranges is believed to be 
strongly influenced by the quality of the habitat, particularly the 
abundance of snowshoe hares, in addition to other factors such as 
gender, age, season, and density of the lynx population (Aubry et al. 
2000, pp. 382-385; Mowat et al. 2000, pp. 276-280). Generally, females 
with kittens have the smallest home ranges while males have the largest 
home ranges (Moen et al. 2004, p. 11). Reported home range size varies 
from 12 mi\2\ (31 km\2\) for females and 26 mi\2\ (68 km\2\) for males 
in Maine (Vashon et al. 2005a, p. 7), 8 mi\2\ (21 km\2\) for females 
and 119 mi\2\ (307 km\2\) for males in Minnesota (Moen et al. 2005, p. 
12), and 34 mi\2\ (88 km\2\) for females and 83 mi\2\ (216 km\2\) for 
males in northwest Montana (Squires et al. 2004b, pp. 15-16).
    The dynamic nature of boreal forest landscapes means that lynx home 
ranges will incorporate a variety of forest stands that are in 
different stages of succession and have differing potential to produce 
prey. In addition, due to the naturally marginal nature of lynx habitat 
within the DPS, the moist boreal forest types that snowshoe hares 
prefer often occur in patches dissected or surrounded by matrix 
habitat. Lynx use the matrix habitat primarily as travel routes between 
foraging areas and denning areas. Although they are not dependent on 
the specific vegetative condition of these habitats (i.e., they are not 
sensitive to forest management practices), the importance of these 
areas as travel routes makes them necessary habitat components for 
lynx.
Forest Type Associations
Maine
    Lynx are more likely to occur in 40 mi\2\ (100 km\2\) landscapes 
with regenerating forest, and less likely to occur in landscapes with 
recent clearcut or partial harvest, (Hoving et al. 2004, pp. 291-292). 
Lynx in Maine select softwood (spruce and fir) dominated, regenerating 
stands (Vashon et al. 2005a, p. 8). Regenerating stands used by lynx 
generally develop 15-30 years after forest disturbance and are 
characterized by dense horizontal structure and high stem density 
within a meter of the ground. These habitats support high snowshoe hare 
densities (Homyack 2003, p. 63; Fuller and Harrison 2005, pp. 716, 719; 
Vashon et al. 2005a, pp. 10-11). At the stand scale, lynx in 
northwestern Maine selected older (11 to 26 year-old), tall (4.6 to 7.3 
m (15 to 24 ft)), regenerating clearcut stands and older (11 to 21 
year-old), partially harvested stands (A. Fuller, University of Maine, 
unpubl. data).
Minnesota
    In Minnesota, lynx primarily occur in the Northern Superior Uplands 
Ecological Section of the Laurentian Mixed Forest Province. 
Historically, this area was dominated by red pine (Pinus resinosa) and 
white pine (Pinus strobus) mixed with aspen (Populus spp.), paper birch 
(Betula papyrifera), spruce, balsam fir (Abies balsamifera), and jack 
pine (Pinus banksiana) (Minnesota Department of Natural Resources 
[Minnesota DNR] 2003, p. 2).
    Preliminary research suggests lynx in Minnesota generally use 
younger stands (less than 50 years) with a conifer component in greater 
proportion than their availability (R. Moen, University of Minnesota, 
unpubl. data). Lynx prefer predominantly upland forests dominated by 
red pine, white pine, jack pine, black spruce (Picea mariana), paper 
birch, quaking aspen (Populus tremuloides), or balsam fir (R. Moen, 
unpubl. data).
Washington
    In the North Cascades in Washington, the majority of lynx 
occurrences were found above 1,250 m (4,101 ft) elevation (McKelvey et 
al. 2000b, p. 243 and 2000d, p. 321; von Kienast 2003, p. 28, Table 2; 
Maletzke 2004, p. 17). In this area, lynx selected Engelman spruce 
(Picea engelmanii)-subalpine fir (Abies lasiocarpa) forest cover types 
in winter (von Kienast 2003, p. 28; Maletzke 2004, pp. 16-17). 
Lodgepole pine (Pinus contorta) is a dominant tree species in the 
earlier successional stages of these climax cover types. Seral 
lodgepole stands contained dense understories and therefore received 
high use by snowshoe hares and lynx (Koehler 1990, pp. 847-848; 
McKelvey et al. 2000d, pp. 332-335).
Northern Rockies
    In the Northern Rocky Mountains, the majority of lynx occurrences 
are associated with the Rocky Mountain Conifer Forest vegetative class 
(Kuchler 1964, p. 5; McKelvey et al. 2000b, p. 246) and occur above 
1,250 m (4,101 ft) elevation (Aubry et al. 2000, pp. 378-380; McKelvey 
et al. 2000b, pp. 243-245). The dominant vegetation that constitutes 
lynx habitat in these areas is subalpine fir, Engelman spruce, and 
lodgepole pine (Aubry et al. 2000, p. 379; Ruediger et al. 2000, pp. 4-
8--4-10). As in the Cascades, lodgepole pine is an earlier successional 
stage of subalpine fir and Engelman spruce climax forest cover types.
Greater Yellowstone Area
    Lynx habitat in the GYA is similar to the Northern Rockies in that 
lynx

[[Page 10866]]

occurrences are generally associated with the Rocky Mountain Conifer 
Forest vegetative class. The primary areas of lynx occurrence in this 
unit occur between 7,382 and 9,843 ft (2,250 and 3,000 m) elevation 
(Aubry et al. 2000, p. 379; McKelvey et al. 2000b, Figure 8.18). 
However, lynx are not limited to these elevation zones. The dominant 
vegetation that constitutes lynx habitat in these areas is subalpine 
fir, Engelman spruce, and lodgepole pine (Aubry et al. 2000, pp. 378-
382; Ruediger et al. 2000, pp. 1-2, 1-3; Murphy et al. 2004, pp. 9-11). 
Lodgepole pine is an earlier successional stage of subalpine fir and 
Engelman spruce cover types. The vegetation characteristics in the GYA 
that support snowshoe hare populations (and form the basis for lynx 
populations) are typically found in a widely scattered mosaic of matrix 
habitat types (Murphy et al. 2005, p. 8-11; Hodges and Mills 2005, p. 
6; Agee 2000, p. 48). In the GYA, lynx exploit hare populations in 
disjunct patches of mesic boreal forest that support relatively dense 
understories (Hodges and Mills 2005, pp. 4-6). In most cases, lynx home 
ranges in the GYA will by necessity incorporate habitat that is not 
typically considered lynx foraging habitat, and is used primarily for 
travel.

Food, Water, Air, Light, Minerals, Or Other Nutritional Or 
Physiological Requirements

a. Snowshoe Hares (Food)
    Snowshoe hare density is the most important factor explaining the 
persistence of lynx populations (Steury and Murray 2004, p. 136). A 
minimum snowshoe hare density necessary to maintain a persistent, 
reproducing lynx population within the contiguous United States has not 
been determined, although Ruggiero et al. (2000, pp. 446-447) suggested 
that at least 0.2 hares per acre (0.5 hares per hectare) may be 
necessary. Steury and Murray (2004, p. 137) modeled lynx and snowshoe 
hare populations and predicted that a minimum of 0.4 to 0.7 hares per 
acre (1.1 to 1.8 hares per hectare) was required for persistence of a 
reintroduced lynx population in the southern portion of the lynx range.
    The boreal forest landscape must contain a mosaic of forest stand 
successional stages to sustain lynx populations over the long term as 
the condition of individual stands changes over time. If the vegetation 
potential (or climax forest type) of a particular forest stand is 
conducive to supporting abundant snowshoe hares, it likely will also go 
through successional phases that are unsuitable as lynx foraging or 
denning habitat (Agee 2000, pp. 62-72; Buskirk et al. 2000b, pp. 403-
408). For example, a boreal forest stand where there has been recent 
disturbance, such as fire or timber harvest, that has resulted in 
little or no understory structure is unsuitable as snowhoe hare habitat 
for lynx foraging. That stand may regenerate into suitable snowshoe 
hare (lynx foraging) habitat within 10 to 25 years, depending on local 
conditions (Ruediger et al. 2000, pp. 1-3, 1-4, 2-2--2-5). However, 
forest management techniques that thin the understory may render the 
habitat unsuitable for hares and, thus, for lynx (Ruediger et al. 2000, 
pp. 2-4--3-2; Hoving et al. 2004, pp. 291-292). Stands may continue to 
provide suitable snowshoe hare habitat for many years until woody stems 
in the understory become too sparse as a result of undisturbed forest 
succession or management (e.g., clearcutting or thinning). Thus, if the 
vegetation potential of the stand is appropriate, a stand that is not 
currently in a condition that is suitable to support abundant snowshoe 
hares for lynx foraging or coarse woody debris for den sites has the 
capability to develop into suitable habitat for lynx and snowshoe hares 
with time.
    As described previously, snowshoe hares prefer boreal forest stands 
that have a dense horizontal understory to provide food, cover, and 
security from predators. Snowshoe hares feed on conifers, deciduous 
trees, and shrubs (Hodges 2000b, pp. 181-183). Snowshoe hare density is 
correlated to understory cover between approximately 3 to 10 ft (1 to 3 
m) above the ground or snow level (Hodges 2000b, p. 184, Table 7.5). 
Habitats most heavily used by snowshoe hares are stands with shrubs, 
stands that are densely stocked, and stands at ages where branches have 
more lateral cover (Hodges 2000b, p. 184). In Maine, the snowshoe hare 
densities were highest in the stands supporting high conifer stem 
densities (Homyack et al. 2004, p. 195; Robinson 2006, p. 69). In 
northcentral Washington, snowshoe hare density was highest in 20-year-
old lodgepole pine stands where the average density of trees and shrubs 
was 6,415 stems per acre (ac) (15,840 stems/hectare (ha)) (Koehler 
1990, p. 848). Generally, earlier successional forest stages support a 
greater density of horizontal understory and more abundant snowshoe 
hares (Buehler and Keith 1982, p. 24; Wolfe et al. 1982, pp. 668-669; 
Koehler 1990, pp. 847-848; Hodges 2000b, pp. 184-191; Griffin 2004, pp. 
84-88); however, sometimes mature stands also can have adequate dense 
understory to support abundant snowshoe hares (Griffin 2004, p. 88). In 
Montana, lynx favor multi-story stands, often in older age classes, 
where tree boughs touch the snow surface but where stem density is low 
(Squires 2006, p. 4).
    In Maine, the highest snowshoe hare densities were found in 
regenerating softwood (spruce and fir) and mixed wood stands (Fuller 
and Harrison 2005, pp. 716, 719; Robinson 2006, p. 69). In the North 
Cascades, the highest snowshoe hare densities were found in 20-year-old 
seral lodgepole pine stands with a dense understory (Koehler 1990, pp. 
847-848). In montane and subalpine forests in northwest Montana, the 
highest snowshoe hare densities in summer were generally in younger 
stands with dense forest structure; in winter snowshoe hare densities 
were as high or higher in mature stands with dense understory forest 
structure (Griffin 2004, p. 53). Snowshoe hare studies are just 
underway in Minnesota (Moen et al. 2005, p. 18); therefore, results on 
habitat relationships are still preliminary. In the GYA, the highest 
snowshoe hare densities were found in a douglas fir site and a few 
regenerating lodgepole pine and lodgepole stands that had a lodgepole 
understory. Low hare densities were found in most regenerating 
lodgepole stands, most likely due to low stem densities (Hodges and 
Mills 2005, p. 6). Spruce-fir forests were the stand type most likely 
to support snowshoe hares; however, hare densities were never high at 
these sites.
    Habitats supporting abundant snowshoe hares must be present in a 
large proportion of the landscape to support a viable lynx population. 
Broad-scale snowshoe hare density estimates are not available for the 
areas we are proposing as lynx revised critical habitat; available 
snowshoe hare density estimates are only applicable for the immediate 
area and time frame for which the study was conducted and cannot be 
extrapolated further.
b. Snow Conditions (Other Physiological Requirements)
    As described in the ``Background'' section above, snow conditions 
also determine the distribution of lynx. Deep, fluffy snow conditions 
likely restrict potential competitors such as bobcat or coyote from 
effectively encroaching on or hunting in winter lynx habitat. Snowfall 
was the strongest predictor of lynx occurrence at a regional scale 
(Hoving et al. 2005, p. 746, Table 5). In addition to snow depth, other 
snow properties, including surface hardness or sinking depth, are 
important factors in the spatial, ecological, and genetic structuring 
of the species (Stenseth et al. 2004, p. 75).

[[Page 10867]]

    In the northeastern United States, lynx are most likely to occur in 
areas with a 10-year mean annual snowfall greater than 105 in (268 cm) 
(Hoving 2001, p. 75). The Northern Superior Uplands section of 
Minnesota, which roughly corresponds to the area proposed as revised 
critical habitat in that State, receives more of its precipitation as 
snow than any section in the State, has the longest period of snow 
cover, and has the shortest growing season (Minnesota DNR 2003, p. 2). 
Mean annual snowfall from 1971 to 2000 in this area was generally 
greater than 55 in (149 cm) (University of Minnesota 2005).
    Information on average snowfall or snow depths in mountainous areas 
such as the Cascades or northwest Montana is limited because few 
weather stations in these regions have measured snow fall or snow depth 
over time. Topography strongly influences local snow conditions. In the 
Cascades, at the Mazama station, average annual snowfall from 1948 to 
1976 was 115 in (292 cm) (Western Regional Climate Center 2005). In 
Montana, at the Seeley Lake Ranger Station, average annual snowfall 
from 1948 to 2005 is 124 in (315 cm), while at the Troy station the 
average total snowfall from 1961 to 1994 was 90 in (229 cm) (Western 
Regional Climate Center 2005).
    We considered the effect climate change could have on average 
snowfall or snow depths when we developed this proposed rule. We have 
information to indicate that up to two-thirds of the lynx range in the 
lower 48 States may become unsuitable by 2100 (Gonzalez et al. 2007, 
pp. 4, 7-8, 10, 13-14, 19). However, we have used current climate 
information in developing this rule because, until regional climate 
projections are more certain, we find it is appropriate to designate 
critical habitat for lynx where they currently exist. Projections for 
habitat loss go out over the next 100 years. If designated habitat 
becomes unsuitable for lynx in the future due to climate change, the 
Service will revise critical habitat to remove unsuitable habitat and 
add new suitable habitat in order to seek to facilitate the shift in 
lynx range that climate change may cause. Lynx distribution and habitat 
is likely to shift upward in elevation and northward in latitude as 
temperatures increase (Gonzalez et al. 2007, pp. 7, 13-14, 19). All 
proposed revised critical habitat units include the highest-elevation 
habitats that lynx would be able to use in the event that they move to 
higher elevations in response to climate change. Additionally, any 
northward shifts in range would likely move the species and its 
suitable habitat into Canada. Four of the five proposed revised 
critical habitat units use the United States/Canada border as their 
northern boundary.

Sites for Breeding, Reproduction, or Rearing (or Development) of 
Offspring--Denning Habitat

    Lynx den sites are found in mature and younger boreal forest stands 
that have a large amount of cover and downed, large woody debris. The 
structural components of lynx den sites are common features in managed 
(logged) and unmanaged (e.g., insect damaged, wind-throw) stands. 
Downed trees provide excellent cover for den sites and kittens and 
often are associated with dense woody stem growth.
    Site characteristics were evaluated for 26 lynx dens from 1999 to 
2004 in northwest Maine. Dens were found in several stand types. Tip-up 
mounds (exposed roots from fallen trees) alone best explained den site 
selection (J. Organ, Service, unpubl. data). Tip-up mounds may purely 
be an index of downed trees, which were abundant on the landscape. 
Horizontal cover at 16 ft (5 m) alone was the next best predictor of 
denning (J. Organ, unpubl. data). Dead, downed trees were sampled, but 
did not explain den site selection as well as tip-up mounds and cover 
at 16 ft (5 m). Lynx essentially select dense cover in a cover-rich 
area.
    In the North Cascades, Washington, lynx denned in mature (older 
than 250 years) stands with an overstory of Engelman spruce, subalpine 
fir, and lodgepole pine with an abundance of downed, woody debris 
(Koehler 1990, p. 847). In this study, all den sites were located on 
north-northeast aspects (Koehler 1990, p. 847). In northwest Montana, 
areas around dens were a variety of ages but all contained abundant 
woody debris including downed logs, blowdowns, and rootwads, and dense 
understory cover (Squires et al. 2004b, Table 3). Information on den 
site characteristics in Minnesota has not yet been reported (Moen et 
al. 2005, p. 8).

Primary Constituent Element for Lynx

    Within the geographical area we know to be occupied by the lynx, we 
must identify the primary constituent elements (PCEs) laid out in the 
quantity and spatial arrangement essential to the conservation of the 
species (i.e., essential physical and biological features) that may 
require special management considerations or protections.
    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species, we have determined that 
the primary constituent element essential to the conservation of the 
lynx is:
    (1) Boreal forest landscapes supporting a mosaic of differing 
successional forest stages and containing:
    (a) Presence of snowshoe hares and their preferred habitat 
conditions, including dense understories of young trees or shrubs tall 
enough to protrude above the snow;
    (b) Winter snow conditions that are generally deep and fluffy for 
extended periods of time;
    (c) Sites for denning having abundant, coarse, woody debris, such 
as downed trees and root wads; and
    (d) Matrix habitat (e.g., hardwood forest, dry forest, non-forest, 
or other habitat types that do not support snowshoe hares) that occurs 
between patches of boreal forest in close juxtaposition (at the scale 
of a lynx home range) such that lynx are likely to travel through such 
habitat while accessing patches of boreal forest within a home range. 
The important aspect of matrix habitat for lynx is that these habitats 
retain the ability to allow unimpeded movement of lynx through them as 
lynx travel between patches of boreal forest.
    We designed the proposed revised critical habitat units to capture 
these elements of the PCE laid out in the quantity and spatial 
arrangement essential to the conservation of the species (i.e., 
essential physical and biological features). To do this, we mapped 
units across the geographic range of the species in the United States 
to protect populations in the event of catastrophic events that could 
impact a portion of the range. We designed each unit to be large enough 
to encompass the temporal and spatial changes in habitat and snowshoe 
hare populations to support interbreeding lynx populations or 
metapopulations over time.

Special Management Considerations or Protections

    When designating critical habitat, we assess whether the occupied 
areas contain the physical and biological features that are essential 
to the conservation of the species and that may require special 
management considerations or protections.
    The area proposed for designation as revised critical habitat will 
require some level of management to address the current and future 
threats to the lynx and to maintain the physical and

[[Page 10868]]

biological features essential to the conservation of the species. In 
all units, special management will be required to ensure that boreal 
forest landscapes provide a mosaic of forest stands of various ages to 
provide abundant prey habitat, denning habitat, and connectivity within 
the landscape. The designation of critical habitat does not imply that 
lands outside of critical habitat do not play an important role in the 
conservation of the lynx. Federal activities that may affect areas 
outside of critical habitat, such as forest management, development, 
and road construction, are still subject to review under section 7 of 
the Act if they may affect lynx because Federal agencies must consider 
both effects to lynx and effects to critical habitat independently. The 
prohibitions of section 9 of the Act (e.g., harm, harass, capture, 
kill) also continue to apply both inside and outside of designated 
critical habitat.
    Special management direction for lynx has been applied to public 
lands in much of the lynx DPS. The USFS, Bureau of Land Management 
(BLM), NPS, and the Service developed a Lynx Conservation Assessment 
and Strategy (LCAS) (Ruediger et al. 2000, entire) using the best 
available science at the time specifically to provide a consistent and 
effective approach to conserve lynx and lynx habitat on Federal lands 
(Ruediger et al. 2000). The overall goals of the LCAS were to recommend 
lynx conservation measures, to provide a basis for reviewing the 
adequacy of USFS and BLM land and resource management plans with regard 
to lynx conservation, and to facilitate conferencing and consultation 
under section 7 of the Act. The LCAS identifies an inclusive list of 17 
potential risk factors for lynx or lynx habitat that may be addressed 
under programs, practices, and activities within the authority and 
jurisdiction of Federal land management agencies. The risks identified 
in the LCAS are based on effects to either individual lynx, lynx 
populations, or both, or to lynx habitat. Potential risk factors the 
LCAS addresses that may affect lynx productivity include: timber 
management, wildland fire management, recreation, forest/backcountry 
roads and trails, livestock grazing, and other human developments. 
Potential risk factors the LCAS addresses that may affect lynx 
mortality include: trapping, predator control, incidental or illegal 
shooting, and competition and predation as influenced by human 
activities and highways. Potential risk factors the LCAS addresses that 
may affect lynx movement include: highways, railroads and utility 
corridors, land ownership pattern, and ski areas and large resorts. 
Other potential large-scale risk factors for lynx addressed by the LCAS 
include: fragmentation and degradation of lynx refugia, lynx movement 
and dispersal across shrub-steppe habitats, and habitat degradation by 
nonnative and invasive plant species.
    The LCAS used the best available information at the time to ensure 
the appropriate mosaic of habitat is provided for lynx on Federal 
lands. Although the LCAS was written specifically for Federal lands, 
many of the conservation measures are pertinent for non-Federal lands. 
To facilitate project planning and allow for the assessment of the 
potential effects of a project on an individual lynx, the LCAS directs 
Federal land management agencies to delineate Lynx Analysis Units 
(LAUs). The scale of an LAU approximates the size of area used by an 
individual lynx (25 to 50 mi\2\ (65 to 130 km\2\)). The LCAS recognizes 
that LAUs will likely encompass both lynx habitat and other areas 
(e.g., lakes, low elevation ponderosa pine (Pinus ponderosa) forest, 
and alpine tundra). Habitat-related standards the LCAS provides to 
address potential risks include: (1) If more than 30 percent of lynx 
habitat in an LAU is currently in unsuitable condition, no further 
reduction of suitable condition shall occur as a result of vegetation 
management activities by Federal agencies; (2) within an LAU, maintain 
denning habitat in patches generally larger than 5 ac (2 ha), 
co