Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for the Contiguous U.S. Distinct Population Segment of the Canada Lynx and Revised Distinct Population Segment Boundary

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R6-ES-2013-0101; 4500030114]

RIN 1018-AZ77

Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for the Contiguous U.S. Distinct Population Segment of the Canada Lynx and Revised Distinct Population Segment Boundary

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Proposed rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service, propose to designate revised critical habitat for the contiguous U.S. distinct population segment (DPS) of the Canada lynx under the Endangered Species Act of 1973, as amended, and to revise the boundary of the Canada lynx DPS. These proposed revisions fulfill our obligations under two settlement agreements. The revised critical habitat proposed rule also addresses issues raised by two courts in 2010. If we finalize this rule as proposed, it would extend the Endangered Species Act's protections to the Canada lynx wherever it occurs in the contiguous United States, including New Mexico, and it would revise this species' critical habitat. The effect of this regulation is to conserve the Canada lynx and its habitats in the contiguous United States under the Endangered Species Act.

DATES:

We will accept comments received or postmarked on or before December 26, 2013. Comments submitted electronically using the Federal eRulemaking Portal (see

ADDRESSES

section, below) must be received by 11:59 p.m. Eastern Time on the closing date.

Public Hearing:

A public hearing will be held on this proposed rule on Monday, November 25, 2013, from 6:00 p.m. to 9:00 p.m. (Mountain Time). The formal public hearing will be preceded by an open house and general information meeting from 2:00 p.m. to 5:00 p.m.

ADDRESSES:

You may submit comments by one of the following methods:

(1)

Electronically:

Go to the Federal eRulemaking Portal:

http://www.regulations.gov.

In the Search box, enter FWS-R6-ES-2013-0101, which is the docket number for this rulemaking. You may submit a comment by clicking on “Comment Now!”

(2)

By hard copy:

Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R6-ES-2013-0101; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments on

http://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).

Public Hearing:

A public hearing will be held on this proposed rule on Monday, November 25, 2013, from 6:00 p.m. to 9:00 p.m. (Mountain Time) at the Red Lion Colonial Hotel, 2301 Colonial Drive, Helena, Montana, 59601. The formal public hearing will be preceded by an open house and general information meeting from 2:00 p.m. to 5:00 p.m.

Public Meeting:

An informational public meeting will be held on Monday, November 4, 2013, from 7:00 p.m. to 9:00 p.m. at the George W. Stearns High School auditorium at 199 State Street, Millinocket, Maine 04462.

People needing reasonable accommodations in order to attend and participate in the public hearing or meeting should contact Jodi Bush, Montana Fish and Wildlife Office, as soon as possible (see

FOR FURTHER INFORMATION CONTACT

).

The coordinates or plot points or both from which the maps are generated are included in the administrative record for this critical habitat designation and are available at

http://www.fws.gov/montanafieldoffice/, http://www.regulations.gov

at Docket No. FWS-R6-ES-2013-0101, and at the Montana Ecological Services Field Office (see

FOR FURTHER INFORMATION CONTACT

). Any additional tools or supporting information that we may develop for this critical habitat designation will also be available at the Fish and Wildlife Service Web site and Field Office set out above, and may also be included in the preamble and/or at

http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Jodi Bush, Field Supervisor, U.S. Fish and Wildlife Service, Montana Ecological Services Field Office, 585 Shepard Way, Suite 1, 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:

Executive Summary

Why we need to publish a rule.

Under the Endangered Species Act (Act), any species that is determined to be threatened or endangered requires critical habitat to be designated, to the maximum extent prudent and determinable. Designations and revisions of critical habitat and revisions to definitions of listed entities can only be completed by issuing a rule. This is a proposed rule to revise the designation of critical habitat for the threatened contiguous United States (U.S.) distinct population segment (DPS) of the Canada lynx

(Lynx canadensis)

and to revise the DPS boundary to extend the protections of the Act to lynx everywhere they occur in the contiguous United States, including New Mexico. The lynx DPS was listed as threatened in 2000. We designated critical habitat for the lynx DPS in 2006 and revised the designation in 2009. Also in 2009, we determined that adding lynx in New Mexico to the listing of the lynx DPS was warranted because lynx that were introduced into Colorado were regularly crossing the State border into New Mexico. In 2010, the U.S. District Courts in the Districts of Montana and Wyoming remanded the revised critical habitat designation to the Service. The Service agreed to submit to the

Federal Register

a proposed rule on the revised designation of critical habitat for the Canada lynx by September 1, 2013. This date was extended to September 20, 2013 by stipulation. As part of the 2011 multidistrict litigation (MDL) agreement, we committed to propose adding lynx in New Mexico to the DPS by September 2013.

This rule would revise the definition of the lynx DPS.

We propose to rescind the existing boundary of the lynx DPS, which is based on State boundaries within the historic distribution of lynx, and replace it with a DPS definition that extends the protections of the Act to lynx wherever they occur in the contiguous United States. This revised boundary would include lynx that occur in New Mexico as a result of lynx introduction efforts in Colorado.

This rule would revise the designation of critical habitat for the lynx DPS.

In total, we propose to designate 41,547 square miles (mi

2

) (107,607 square kilometers (km

2

)) of critical habitat in five units in the States of Idaho, Maine, Minnesota, Montana, Washington, and Wyoming. We propose to redesignate those areas we designated in 2009 along with additional areas in northern Maine and northwestern Wyoming (see details and list of counties under

Proposed Revised Critical Habitat Designation,

below). We propose to exclude from critical habitat Tribal lands and some State and private lands managed in

accordance with approved lynx conservation plans. If these exclusions are finalized, the area designated as critical habitat would be 39,632 mi

2

(102,647 km

2

), which would be 632 mi

2

(1,637 km

2

)—1.6 percent—larger than the area we designated in 2009.

The basis for our revised critical habitat action.

Section 4(b)(2) of the Act states that the Secretary shall designate and make revisions to critical habitat on the basis of the best available scientific data after taking into consideration the economic impact, national security impact, and any other relevant impact of specifying any particular area as critical habitat. The Secretary may exclude an area from critical habitat if she determines that the benefits of such exclusion outweigh the benefits of specifying such area as part of the critical habitat, unless she determines, based on the best scientific data available, that the failure to designate such area as critical habitat will result in the extinction of the species. We will consider excluding from the final designation (1) Tribal lands, (2) lands in Maine managed in accordance with the Natural Resources Conservation Service's Healthy Forest Reserve Program, (3) lands in Montana managed in accordance with the Montana Department of Natural Resources and Conservation (DNRC) Forested State Trust Lands Habitat Conservation Plan, and (4) lands in Washington managed in accordance with the Washington Department of Natural Resources (DNR) Lynx Habitat Management Plan for DNR-managed Lands.

We will prepare an economic analysis.

We prepared a final economic analysis to evaluate the potential economic impacts of our 2009 critical habitat designation. To ensure that we adequately consider the economic impacts of the current proposed designation, we will prepare an economic analysis of this proposed designation and make it available for public comment.

We will prepare a National Environmental Policy Act analysis.

Because this rule proposes designation of critical habitat in States within the jurisdiction of the U.S. Court of Appeals for the Tenth Circuit, we will prepare an analysis in accordance with the National Environmental Policy Act (NEPA; 42 U.S.C. 4321

et seq.

). We will update and revise our 2009 NEPA analysis based on the current proposed critical habitat designation and notify the public of the availability of the draft environmental assessment.

We will seek peer review.

We are seeking comments from independent specialists to ensure that our critical habitat designation is based on scientifically sound data, assumptions, and analyses. We have invited these peer reviewers to comment on our specific assumptions and conclusions in this revised critical habitat designation. Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal. In addition to public and peer-review comments received on this proposed rule, between the proposed and final rules, the Service will continue to evaluate (1) any new information that becomes available regarding the status and distribution of lynx in the contiguous United States, (2) any refinements of or improvements to lynx habitat mapping and/or modeling, particularly those efforts currently under way on National Forest lands, (3) new information regarding the potential effects of climate change on lynx and its habitats, (4) new information regarding the potential effects of forest management on lynx and its habitats, and (5) any other new information that was not considered previously to determine the relevance of such information in revising critical habitat for lynx. If necessary and appropriate, revisions to this proposed rule will be made to address such information.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned government agencies, the scientific community, industry, or any other interested party concerning this proposed rule. We particularly seek comments concerning:

(1) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531

et seq.

) including whether there are threats to the species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threat outweighs the benefit of designation such that the designation of critical habitat may not be prudent.

(2) Specific information on:

(a) The amount and distribution of lynx habitat in the contiguous United States;

(b) What areas that were occupied at the time of listing and that contain features essential to the conservation of the DPS should be included in the designation and why;

(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change and changing forest management practices; and

(d) What areas not occupied at the time of listing may be essential for the conservation of the DPS and why, including areas that remain unoccupied, such as the “Kettle Range” in Ferry County, Washington, and areas recently occupied, such as northern New Hampshire (in northern Coos County), northeastern Vermont (in northern Essex County), western Maine in Somerset, Franklin, and northern Oxford Counties, including portions of the White Mountain National Forest, and eastern Maine in northern Washington County.

(3) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed revised critical habitat.

(4) Comments or information that may assist in identifying or clarifying the primary constituent element.

(5) Whether lands in the Southern Rocky Mountains of Colorado, northern New Mexico, and southern Wyoming (a) contain the physical and biological features essential for the conservation of the DPS, (b) contain these features in the quantities and spatial arrangements across landscapes necessary to support lynx populations over time, and (c) are essential to the conservation of the DPS, and the basis for why that might be so.

(6) Whether lands in the Clearwater and Nez Perce National Forests in Idaho, the Bitterroot National Forest in Idaho and Montana, the Beaverhead-Deerlodge National Forest in Montana, and parts of the Helena and Lolo National Forests in Montana not currently proposed for designation (a) contain the physical and biological features essential for the conservation of the DPS, (b) contain these features in the quantities and spatial arrangements across landscapes necessary to support lynx populations over time, and (c) are essential to the conservation of the DPS, and the basis for why that might be so.

(7) How the proposed boundaries of the revised critical habitat designation could be refined to more closely circumscribe the boreal forest landscapes essential to the conservation of lynx.

(8) Information on the projected and reasonably likely impacts of climate change on lynx and proposed critical habitat.

(9) Any probable economic, national security, or other relevant impacts of designating any area that may be

included in the final designation; in particular, any impacts on small entities or families, and the benefits of including or excluding areas that exhibit these impacts.

(10) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area. In particular, we are considering excluding all Tribal lands (Maine, Minnesota, and Montana) as well as lands in (a) Maine, managed in accordance with the Natural Resources Conservation Service's Healthy Forest Reserve Program (75 FR 6539, February 10, 2010), (b) Montana, managed in accordance with the Montana DNRC Forested State Trust Lands Habitat Conservation Plan (Montana DNRC and U.S. Fish and Wildlife Service 2010), and (c) Washington, managed in accordance with the Washington DNR Lynx Habitat Management Plan for DNR-managed Lands (Washington DNR 2006).

(11) 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.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in

ADDRESSES

. We request that you send comments only by the methods described in the

ADDRESSES

section.

We will post your entire comment—including your personal identifying information—on

http://www.regulations.gov.

You may request at the top of your document that we withhold personal information such as your street address, phone number, or email address 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 proposed rule, will be available for public inspection on

http://www.regulations.gov

, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Montana Ecological Services Field Office (see

FOR FURTHER INFORMATION CONTACT

).

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), the

Recovery Outline for the Contiguous United States DPS of Canada Lynx

(Recovery Outline; U.S. Fish and Wildlife Service 2005, entire) the final rule designating critical habitat for lynx published in the

Federal Register

on November 9, 2006 (71 FR 66008), the final rule designating revised critical habitat published in the

Federal Register

on February 25, 2009 (74 FR 8616), and the 12-month finding on a petition to change the final listing of the DPS of the Canada lynx to include New Mexico published in the

Federal Register

on December 17, 2009 (74 FR 66937). These documents and others addressing the status and conservation of lynx in the contiguous United States may be viewed and downloaded from the Service's Web site:

http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A073

.

On July 28, 2010, the U.S. District Court for the District of Montana remanded the 2009 revised critical habitat final rule to the Service because of flaws it perceived in the Service's rationale for its decision not to designate critical habitat in Colorado and in the Beaverhead-Deerlodge, Bitterroot, Clearwater, and Nez Perce National Forests in Idaho and Montana, and in portions of the Helena and Lolo National Forests in Montana not included in the designation. The court ordered the Service to determine whether areas occupied by lynx introduced into Colorado possess the physical and biological features essential to the conservation of the species, and consider the physical and biological features of occupied forests in Montana and Idaho to determine whether they should be designated as critical habitat. The court also ordered that the 2009 final critical habitat rule “. . . shall remain in place until the Service issues a new final rule on lynx critical habitat, at which time the current, invalidated Final Rule (74 FR 8616) will be superseded.”

On September 10, 2010, because of its concerns with the Service's consideration of potential economic impacts to recreational snowmobiling interests in Washington State, the U.S. District Court for the District of Wyoming enjoined the final critical habitat rule “. . . pending review and consideration by the Secretary of the full analysis of all the economic impacts, and a determination on the exclusion request of the Washington State Snowmobile Association . . .”. The Court enjoined the final rule only in regard to National Forest Lands in Washington State (Unit 4) “. . . currently managed by . . .” the Lynx Conservation Assessment and Strategy (LCAS).

In this proposed rule, the Service addresses the issues raised by the courts, evaluates recent lynx research and data, considers additional areas for inclusion in critical habitat and other areas for exclusion under section 4(b)(2) of the Act, and proposes this revised critical habitat designation based on the best available scientific and commercial data.

We also propose to rescind the existing State-boundary-based definition of the lynx DPS and replace it with a definition that extends the Act's protections to lynx “where found” in the contiguous United States. This change would ensure that lynx, which are known for their long-distance dispersal capability and tendency to occur in places well outside of typical habitats, receive the Act's protections wherever they occur in the contiguous United States, including (but not limited to) New Mexico.

Revised Definition of the Contiguous U.S. Distinct Population Segment of the Canada Lynx

In the final listing rule for the Canada lynx, dated March 24, 2000, the Service defined the contiguous U.S. DPS of lynx based on the international boundary with Canada and state boundaries of all 14 States in the historic and current range of lynx (65 FR 16052; 74 FR 66937). With that definition, New Mexico was not included in the listed area because no lynx occurred there, historic records did not show lynx in the State, and it lacked lynx habitat.

On December 17, 2009, the Service published a 12-month “warranted but precluded” finding in the

Federal Register

on a petition to expand the listing of the Canada lynx to include the State of New Mexico (74 FR 66937). That finding was made in response to an August 8, 2007, petition from a coalition of environmental groups and a 2008 settlement agreement. In the finding, the Service acknowledged that lynx associated with a lynx introduction effort in Colorado were regularly and frequently crossing the State boundary between Colorado and New Mexico and that, when they did, they were no longer protected by the Act because New Mexico was not included in the listed DPS area. In 2011, as part of the MDL settlement agreement, the Service agreed to amend the listing rule to include New Mexico so that lynx entering New Mexico from Colorado would no longer lose Federal protection under the Act upon crossing the State boundary.

We have determined that lynx entering New Mexico, or any other States not currently included in the DPS as described in the 2000 final listing rule, should not lose their protection under the Act upon doing so. Therefore, with this rule, we propose to rescind the State-boundary-based definition of the contiguous U.S. lynx DPS and replace it in regulation with a definition of the DPS that extends the Act's protections to lynx “where found within contiguous United States.” This change will ensure that all lynx in the contiguous United States receive protection under the Act regardless of where they may wander, including New Mexico.

Designation of Revised Critical Habitat for the Contiguous U.S. Distinct Population Segment of the Canada Lynx

Background

It is our intent to discuss below only topics relevant to the revised designation of critical habitat in this proposed rule. For more information about the listing of the Canada lynx, please refer to the Previous Federal Actions section above.

Species Information

Taxonomy and Species Description

The Canada lynx (order Carnivora; family Felidae) is a medium-sized cat with long legs and large, well-furred paws. Its long, black ear tufts and short, black-tipped tail distinguish the lynx from the similar but much more common bobcat (

Lynx rufus

). In winter, the lynx's fur is dense and has a grizzled appearance with grayish-brown mixed with buff or pale brown fur on the back, and grayish-white or buff-white fur on the belly, legs and feet. In summer, its fur is more reddish to gray-brown (McCord and Cardoza 1982, p. 730). Lynx generally measure 30 to 35 inches (in) (75 to 90 centimeters (cm)) long and weigh 14 to 31 pounds (lb) (6 to 14 kilograms (kg)) (Quinn and Parker 1987, Table 1; Moen

et al.

2010a, Figure 2; Maine Department of Inland Fisheries and Wildlife 2012,

unpublished data

). The lynx's large feet and long legs make it highly adapted for traversing and hunting in deep snow. Lynx hybridization with bobcats has been documented in Minnesota, Maine, and New Brunswick (Schwartz

et al.

2004, entire; Homyack

et al.

2008, entire), where male bobcats bred with female lynx to produce fertile offspring with lynx-like ear tufts, intermediate foot-size, and bobcat-like fur (Interagency Lynx Biology Team 2013, p. 35). Canada lynx are related to the somewhat larger Eurasian lynx (

Lynx lynx

), which occupies a similar boreal forest distribution in northern Europe, northern Russia, and central Asia (von Arx

et al.

2001, pp. 8-10).

Distribution

The Canada lynx is broadly distributed across northern North America from eastern Canada to Alaska (McCord and Cardoza 1982, p. 729). It is strongly associated with the expansive, continuous boreal forests of those areas, and its range largely overlaps that of its primary prey, the snowshoe hare (

Lepus americanus

), also a boreal forest specialist (Bittner and Rongstad 1982, p. 146; Mowat

et al.

2000, pp. 268-269; Aubry

et al.

2000, p. 375). The southern periphery of the boreal forest extends into parts of the northern contiguous United States, where it transitions to the Acadian forest in the Northeast (Seymour and Hunter 1992, pp. 1, 3), deciduous temperate forest in the Great Lakes regions, and subalpine forest in the Rocky Mountains and Cascade Mountains in the west (Agee 2000, pp. 40-41). In the contiguous United States, these transitional boreal forests become discontinuous and patchy, preventing both lynx and hares from broadly achieving densities similar to those of the northern boreal forests (Wolff 1980, pp. 123-128; Buehler and Keith 1982, pp. 24, 28; Koehler 1990, p. 849; Koehler and Aubry 1994, p. 84; Aubry

et al.

2000, pp. 373-375, 382, 394). These forests eventually become too fragmented and isolated in the contiguous United States to support hares at the landscape densities and distributions necessary to support lynx home ranges (Interagency Lynx Biology Team 2013, p. 77) or lynx populations over time (see also Habitat and Biology, below).

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 or coyotes (

Canis latrans

) (McCord and Cardoza 1982, p. 748; Buskirk

et al.

2000b, pp. 86-95; Ruediger

et al.

2000, pp. 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 hunt efficiently 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. These adaptations may also help lynx avoid predators such as mountain lions (

Puma concolor;

Squires and Laurion 2000, p. 346) and fisher (

Martes pennanti;

Vashon

et al.

2012, p. 20), which also have higher foot-loading, making them less efficient in deep, fluffy snow conditions (Krohn

et al.

2005, entire).

Lynx occurrence has been documented in 24 States in the northern contiguous United States (McKelvey

et al.

2000a, entire). However, northern (Canadian and Alaskan) lynx populations are cyclic, with large population swings occurring over 8- to 11-year intervals and lagging a year or two behind snowshoe hare population cycles (Elton and Nicholoson 1942, entire; Mowat

et al.

2000, pp. 281-294; Interagency Lynx Biology Team 2013, p. 33). When hares are abundant, northern lynx populations increase quickly and dramatically; when hare numbers subsequently decline, large numbers of lynx disperse widely in search of food (Slough and Mowat 1996, pp. 956-957; Mowat

et al.

2000, pp. 281-294). Historically, during and after these events, often referred to as lynx population “irruptions,” many lynx dispersed into the northern contiguous United States, often occurring temporarily in habitats that are incapable of supporting lynx populations over time (Thiel 1987, entire; McKelvey

et al.

2000a, pp. 241-242, 253). Many records of lynx in the contiguous United States appear to be related to such events (McKelvey

et al.

2000a, entire; see also Biology and

Criteria Used To Identify Critical Habitat,

below).

Persistent, productive lynx populations (interbreeding lynx populations that have occupied particular areas consistently over time) in the contiguous United States occur in northern Maine, northeast Minnesota, northwest Montana/northeast Idaho, north-central Washington, and the Greater Yellowstone Area of southwest Montana and northwest Wyoming. Recently, lynx reproduction also has been documented in northern New Hampshire (in 2010 and 2011), northern Vermont (in 2009, 20011, and 2012), eastern Maine (in 2010), and breeding is likely in some areas of western Maine (U.S. Fish and Wildlife Service 2013a, p. 1). Whether the small breeding populations in New Hampshire and Vermont will persist is uncertain (Interagency Lynx Biology Team 2013, p. 23), and regional-scale modeling suggests that habitat and snow conditions there are likely insufficient

to support viable lynx populations over time (Hoving

et al.

2005, pp. 739, 749). Additionally, from 1999 to 2006, researchers captured 218 lynx in Alaska and Canada and released them into high-elevation forests in western Colorado (Devineau

et al.

2010, entire). Although 122 (56 percent) of these lynx had died by June 2010 (Shenk 2010, pp. 1, 5), some subsequently established home ranges in Colorado and produced kittens in some years. Some also dispersed into northern New Mexico, northeastern Utah, and southern and western Wyoming, though no reproduction has been documented among any of the lynx that left Colorado. Other lynx from this introduced population traveled through Wyoming, Montana, and Idaho, and into southern Canada, and others traveled to Arizona, southern Utah, eastern Nevada, Kansas, Nebraska, Iowa, and South Dakota, with most of the latter animals ultimately dying in inhospitable habitats in those places (Devineau

et al.

2010, p. 526, Figure 1).

Populations that are composed of a number of discrete subpopulations, connected by dispersal, are called metapopulations (Hanski and Gilpin 1991, entire; McKelvey

et al.

2000b, p. 25). Lynx populations in the contiguous United States appear to function as metapopulations (McKelvey

et al.

2000b, pp. 21, 33; 65 FR 16052-16082; 68 FR 40077-40099; 71 FR 66025-66035; 74 FR 8616-8641). They are generally small populations isolated from one another, though most are directly connected to larger lynx populations in Canada (McKelvey

et al.

2000b, pp. 25-34; U.S Fish and Wildlife Service 2005, p. 2). Lynx disperse in both directions across the Canada-U.S. border (Aubry

et al.

2000, pp. 386-387; Moen

et al.

2010b, pp. ii, 17, 19; Vashon

et al.

2012, p. 22), and this connectivity and interchange with lynx populations in Canada is thought to be essential to the maintenance and persistence of lynx populations in the contiguous United States (McKelvey

et al.

2000b, p. 33; U.S Fish and Wildlife Service 2005, p. 2; Interagency Lynx Biology Team 2013, p. 34, 42, 47, 54, 60, 65; Squires

et al.

2013, p. 187).

The small number of breeding lynx in northeastern Vermont, northern New Hampshire, and western and eastern Maine are indirectly connected to the Canadian population via extensive core habitat in northern Maine. The small lynx population in the Greater Yellowstone Area of southwest Montana and northwest Wyoming is indirectly connected to the Canadian population via the Northern Rocky Mountains lynx population in northwest Montana and northeast Idaho, and by dispersal corridors (habitat “stepping stones”) between northwest Montana and the Greater Yellowstone Area. The Southern Rocky Mountains, particularly in Colorado, lack such habitat “stepping stones” from the north, and the subalpine forests there appear to be functionally disjunct from northern lynx populations and habitats (McKelvey

et al.

2000a, p. 230; Interagency Lynx Biology Team 2013, pp. 50, 54). Although some of the lynx released into Colorado subsequently dispersed northward, these movements should be interpreted with caution and may not be representative of natural lynx dispersal behavior. During unprecedentedly large irruptions of lynx from Canada into the contiguous United States in the early 1960s and again in the early 1970s, few lynx were documented in Colorado, despite large-scale survey efforts, and no viable populations of lynx occurred there prior to the State's introduction efforts (McKelvey

et al.

2000a, pp. 231, 242).

Habitat

Lynx are highly specialized predators of snowshoe hares and are dependent on landscapes with high-density snowshoe hare populations for survival and reproduction (McCord and Cardoza 1982, p. 744; Quinn and Parker 1987, pp. 684-685; Aubry

et al.

2000, pp. 375-378). Estimates of landscape-scale hare densities needed to support lynx populations in the contiguous United States have ranged from 0.2 to 0.7 hares per acre (ac) (0.5 to 1.8 hares per hectare (ha)) (Ruggiero

et al.

2000, pp. 446-447; Steury and Murray 2004, p. 137; Moen

et al.

2012, p. 352; Simons-Legaard

et al.

2013, p. 574). 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.

2000a, 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). 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, pp. 684-685; Agee 2000, pp. 39-47; Aubry

et al.

2000, pp. 373-375; Buskirk

et al.

2000a, pp. 397-405; Ruggiero

et al.

2000, pp. 445-447). The boreal forests that lynx use in the contiguous United States are characterized by patchily-distributed moist forest types with high hare densities in a matrix of other habitats (e.g., hardwoods, dry forest, non-forest) with low landscape 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 lynx foraging occurs.

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, where there also is increased prevalence of non-forested land uses (e.g., agriculture, development). This generally limits snowshoe hare populations in the contiguous United States from achieving landscape densities similar to those of the expansive northern boreal forest in Canada, where snowshoe hares are generally more abundant and more evenly distributed across the landscape (Wolff 1980, pp. 123-128; Buehler and Keith 1982, pp. 24, 28; Koehler 1990, p. 849; Koehler and Aubry 1994, p. 84). Consequently, important foraging habitat for lynx is often more limited and fragmented in the contiguous United States than it is in the northern boreal forests of Canada and Alaska (Berg and Inman 2010, p. 6) and overall habitat quality is lower. In some areas, patches of habitat containing snowshoe hares become so small and fragmented that the landscape cannot support lynx home ranges (Interagency Lynx Biology Team 2013, p. 77) or populations. 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 U.S. 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.

The boreal forest landscape is naturally dynamic. Forest stands within the landscape change as they undergo succession (transition from one stage in the development of a mature forest to another) 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 a shifting mosaic of habitat patches of variable and continually changing quality. That is, boreal forests contain stands of differing ages and conditions, some of which provide lynx

foraging or denning habitat (or may provide these in the future depending on patterns of disturbance and forest succession) and some of which serve as travel routes for lynx moving between foraging and denning habitats (McKelvey

et al.

2000c, pp. 427-434; Hoving

et al.

2004, pp. 290-292).

Because lynx population dynamics, survival, and reproduction are closely tied to snowshoe hare availability, snowshoe hare habitat is the primary component of lynx habitat. Lynx generally concentrate their foraging and hunting activities in areas where snowshoe hare densities 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; Simons-Legaard

et al.

2013, pp. 573-575). Snowshoe hares feed on conifers, deciduous trees, and shrubs (Hodges 2000b, pp. 181-183) and 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).

Over much of the lynx's range, hare densities are higher in regenerating, earlier successional forest stages because they often 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, pp. 63, 141; Griffin 2004, pp. 84-88). Because understory density within a forest stand changes over time as the stand undergoes succession, (i.e., as earlier successional stages with dense understories advance to more mature stands with reduced understory structure), hare habitat quality and corresponding hare densities also shift continually across boreal forest landscapes. However, snowshoe hares can be abundant in mature forests with dense understories, particularly in the Northern Rocky Mountains portion of the DPS (Griffin 2004, pp. 53-54; Hodges

et al.

2009, p. 876; Squires

et al.

2010, pp. 1648, 1653-1657; Berg

et al.

2012, pp. 1483-1487), and these mature forests may be a source of hares for other adjacent forest types (Griffin and Mills 2009, pp. 1492, 1495-1496). Lynx do not occur everywhere within the range of snowshoe hares in the contiguous United States (Bittner and Rongstad 1982, p. 146; McCord and Cardoza 1982, p. 729). This may be due to inadequate abundance, density, or spatial distribution of hares in some places, or the absence of snow conditions that would allow lynx to express a competitive advantage over other hare predators, or a combination of these factors.

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 1990, pp. 847-849; Slough 1999, p. 607; Squires and Laurion 2000, pp. 346-347; Organ

et al.

2008, entire; Squires

et al.

2008, pp. 1497, 1501-1505; Moen and Burdett 2009, entire). 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. 274-275), although in western Montana, 80 percent of documented dens occurred in mature stands (Squires

et al.

2008, p. 1497).

Biology

Because of the patchiness and temporal nature of high-quality snowshoe hare habitat across much of the range of lynx in the contiguous United States, lynx populations in the DPS require large boreal forest landscapes with high average snowshoe hare densities to ensure that sufficient high-quality snowshoe hare habitat is available and to ensure that lynx may move freely among patches of habitat and among subpopulations of lynx. Individual lynx maintain large home ranges, reported as generally ranging from 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.

2004a, pp. 13-16, Table 6; Vashon

et al.

2005a, pp. 7-11, Vashon

et al.

2008, p. 1479). The size of lynx home ranges varies depending on abundance of snowshoe hares, the lynx'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; Vashon

et al.

2008, pp. 1482-1485). When hare densities decline, for example, lynx enlarge their home ranges to obtain sufficient amounts of food to survive and reproduce (Slough and Mowat 1996, p. 956; Mowat

et al.

2000, pp. 265, 278). When hare densities are very low and lynx hunting success declines, many lynx abandon home ranges and disperse, often over long distances, in search of areas with greater food resources (Slough and Mowat 1996, pp. 956-957; Mowat

et al.

2000, pp. 290-294). Although some of these dispersing lynx survive and reestablish home ranges elsewhere, many never find areas of high hare densities and die en route, often soon after initiating dispersal (Mowat

et al.

2000, p. 293).

Lynx are highly mobile and regularly move long distances (greater than 60 mi (100 km)) (Aubry

et al.

2000, pp. 386-387; Mowat

et al.

2000, pp. 290-294; Moen

et al.

2010b, pp. ii, 17-19; Vashon

et al.

2012, pp. 21-22). Lynx disperse primarily when previously adequate habitats become temporarily inadequate due to snowshoe hare population declines (Ward and Krebs 1985, pp. 2821-2823; Slough and Mowat 1996, p. 956; O'Donoghue

et al.

1997, pp. 156, 159; Poole 1997, pp. 499-503). Lynx may disperse at any time of year (Moen

et al.

2010b, pp. ii, 5). Subadult lynx disperse even when hares are 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).

Snowshoe hares comprise a majority of the lynx diet throughout its range (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.

2004a, p. 15, Table 8), and hare abundance is the major driver of lynx population dynamics (see below). Lynx prey opportunistically on other small mammals and birds, particularly during lows in snowshoe hare populations, but alternate prey species do not sufficiently compensate for low availability of snowshoe hares, and lynx populations cannot persist over time in areas with consistently low hare densities (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).

Lynx populations in Canada fluctuate in response to the cycling of snowshoe hare populations (Elton and Nicholson 1942, pp. 241-243; Hodges 2000a, pp. 118-123; Mowat

et al.

2000, pp. 265-272), with synchronous fluctuations in lynx numbers emanating from the core of the Canadian population and spreading over vast areas, generally lagging hare numbers by one year (McKelvey

et al.

2000a, pp. 232, 239; Mowat

et al.

2000, pp. 266, 270). When hares are abundant, lynx have larger litter sizes, higher kitten survival, and lower adult mortality, resulting in rapid population growth during the increase phase of the hare cycle (Slough and Mowat 1996, pp. 955-956; Mowat

et al.

2000, pp. 266, 270-272, 281-289). 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). When hares decline, lynx mortality rates increase, largely because of starvation, as do home range sizes and dispersal/emigration rates (Ward and Krebs 1985, pp. 2821-2823; O'Donoghue

et al.

1997, pp. 156, 159; Poole 1997, pp. 499-503; Mowat

et al.

2000, pp. 265-272, 278, 281-294). Lynx numbers decline dramatically during the “crash” phase of the hare cycle (Slough and Mowat 1996, p. 956; Mowat

et al.

2000, p. 283), with large numbers of lynx dispersing in search of food. Historically, this has resulted in irruptions—large numbers of lynx entering the northern contiguous U.S.—such as the unprecedented “explosions” of lynx observed in the 1960s and 1970s (McKelvey

et al.

2000a, p. 242). During these events, many lynx occurred in anomalous habitats, suffered high mortality, and numbers declined dramatically within a few years of irruptive peaks (Thiel 1987, entire; McKelvey

et al.

2000a, p. 242).

Although snowshoe hare populations in Canada show strong, regular population cycles, these types of synchronous, intrinsically generated fluctuations are generally much less pronounced or absent entirely among hare populations in the contiguous United States (Hodges 2000b, pp. 165-173; Hodges

et al.

2009, pp. 870, 875-876; Scott 2009, pp. 1-44). In the contiguous United States, the degree to which regional lynx population fluctuations are influenced by local snowshoe hare population dynamics is unclear. However, it is anticipated that because of variability in the timing and intensity of lynx irruptions from Canada, and natural fluctuations in snowshoe hare populations, there will be periods when lynx densities within the DPS are extremely low. This dynamic likely predated the historical lynx record and we consider such fluctuations, including periods of very low lynx density, to be a natural part of lynx dynamics in the contiguous U.S. DPS. Where lynx populations are contiguous with cyclic hare populations in Canada, lynx presence and population dynamics in the contiguous United States appear to be more influenced by the occurrence of irruptions from Canada than by intrinsically generated snowshoe hare population cycles within the DPS range.

Critical Habitat

Background

Critical habitat is defined in section 3 of the Act as:

(1) The specific areas within the geographical area occupied by the 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) Which may require special management considerations or protection; and

(2) Specific areas outside the geographical area occupied by the 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 to use and the use of all methods and procedures that are necessary to bring an endangered or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transplantation, and, in the extraordinary case where population pressures within a given ecosystem cannot be otherwise relieved, may include regulated taking.

Critical habitat receives protection under section 7 of the Act through the requirement that Federal agencies ensure, in consultation with the Service, that any action they authorize, fund, or carry out is not likely to result in the destruction or adverse modification of critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by non-Federal landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) of the Act would apply, but even in the event of a destruction or adverse modification finding, the obligation of the Federal action agency and the landowner is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.

Under the first prong of the Act's definition of critical habitat, areas within the geographical area occupied by the species at the time it was listed are included in a critical habitat designation if they contain physical or biological features (1) which are essential to the conservation of the species and (2) which may require special management considerations or protection. For these areas, critical habitat designations identify, to the extent known using the best scientific and commercial data available, those physical or biological features that are essential to the conservation of the species (such as space, food, cover, and protected habitat). In identifying those physical and biological features within an area, we focus on the principal biological or physical constituent elements (primary constituent elements such as roost sites, nesting grounds, seasonal wetlands, water quality, tide, soil type) that are essential to the conservation of the species. Primary constituent elements are those specific elements of the physical or biological features that provide for a species' life-history processes and are essential to the conservation of the species.

Under the second prong of the Act's definition of critical habitat, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed, upon a determination that such areas are essential for the conservation of the species. For example, an area currently occupied by the species but that was not occupied at the time of listing may be essential to the conservation of the species and may be included in the critical habitat designation. We designate critical habitat in areas outside the geographical area occupied by a species only when a designation limited to its range would be inadequate to ensure the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific 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. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas should be designated 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 (if one has been completed), articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, other unpublished materials, or experts' opinions or personal knowledge.

Habitat is generally dynamic, and species may move from one area to another over time. We recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine 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 needed for recovery of the species. Areas that are important to the conservation of the species, both inside and outside the critical habitat designation, will continue to be subject to: (1) conservation actions implemented under section 7(a)(1) of the Act, (2) regulatory protections afforded by the requirement in section 7(a)(2) of the Act for Federal agencies to ensure their actions are not likely to jeopardize the continued existence of any endangered or threatened species, and (3) section 9 of the Act's prohibitions on taking any individual of the species, including taking caused by actions that affect habitat. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. These protections and conservation tools will continue to contribute to recovery of this species. 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), or other species conservation planning efforts if new information available at the time of these planning efforts calls for a different outcome.

Prudency Determination

Section 4(a)(3) of the Act, as amended, and implementing regulations (50 CFR 424.12), require that, to the maximum extent prudent and determinable, the Secretary shall designate critical habitat at the time the species is determined to be an endangered or threatened species. Our regulations (50 CFR 424.12(a)(1)) state that the designation of critical habitat is not prudent when one or both of the following situations exist:

(1) The species is threatened by taking or other human activity, and identification of critical habitat can be expected to increase the degree of threat to the species, or

(2) such designation of critical habitat would not be beneficial to the species.

There is currently no imminent threat of take attributed to collection or vandalism under Factor B for Canada lynx, and identification and mapping of critical habitat is not expected to initiate any such threat. In the absence of finding that the designation of critical habitat would increase threats to a species, if there are any benefits to a critical habitat designation, then a prudent finding is warranted. Here, the potential benefits of designation include: (1) Triggering consultation under section 7 of the Act, in new areas for actions in which there may be a Federal nexus where it would not otherwise occur because, for example, it is or has become unoccupied or the occupancy is in question; (2) focusing conservation activities on the most essential features and areas; (3) providing educational benefits to state or county governments or private entities; and (4) preventing people from causing inadvertent harm to the species. Therefore, because we have determined that the designation of critical habitat will not likely increase the degree of threat to the species and may provide some measure of benefit, we find that designation of critical habitat is prudent for the Canada lynx DPS.

Critical Habitat Determinability

Having determined that designation is prudent, under section 4(a)(3) of the Act we must find whether critical habitat for lynx is determinable. Our regulations at 50 CFR 424.12(a)(2) state that critical habitat is not determinable when one or both of the following situations exist:

(i) Information sufficient to perform required analyses of the impacts of the designation is lacking, or

(ii) The biological needs of the species are not sufficiently well known to permit identification of an area as critical habitat.

When critical habitat is not determinable, the Act allows the Service an additional year to publish a critical habitat designation (16 U.S.C. 1533(b)(6)(C)(ii)).

We reviewed the available information pertaining to the biological needs of the species and habitat characteristics where lynx occur. This and other information represent the best scientific data available and led us to conclude that the designation of critical habitat is determinable for the Canada lynx DPS.

Physical or Biological Features

In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and regulations at 50 CFR 424.12, in determining which areas within the geographical area occupied by the species at the time of listing to designate as critical habitat, we consider the physical or biological features that are essential to the conservation of the species and which may require special management considerations or protection. These 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.

We derive the specific physical or biological features essential for the Contiguous U.S. DPS of the Canada lynx from studies of this species' habitat, ecology, and life history as described below. Additional information on the habitat, ecology, and life history of the lynx DPS can be found in the documents listed above under Previous Federal Actions. We have determined, as we did in the 2009 final critical habitat rule, that the following physical or biological features are essential for lynx:

Space for Individual and Population Growth and for Normal Behavior

Boreal Forest Landscapes

Lynx populations respond to biotic and abiotic factors at different scales. At the regional scale, boreal forests, snow conditions, and competitors (especially bobcat) influence the species' range (Aubry

et al.

2000, pp. 378-380; McKelvey

et al.

2000a, 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, forest management, and development) may influence the spatial and temporal distribution of lynx populations by affecting the distribution of high quality 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 (vegetation community) scale, the quality, quantity, and juxtaposition of habitats influence home range location and size, productivity, and survival (Aubry

et al.

2000, pp. 380-390; Vashon

et al.

2005a, pp. 9-11). At the smaller substand (within-stand) scale, the spatial distribution and abundance of prey and microclimate likely influence lynx movements, hunting behavior, and den and resting site locations (Organ

et al.

2008, entire; Squires

et al.

2008, entire; Moen and Burdett 2009, p. 16; Squires

et al.

2010, pp. 1648, 1654-1657).

All of the physical and biological features of critical habitat for lynx are found only 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). That is, no individual small-scale area or site is likely to have all of the physical and biological features lynx need to survive. Rather, lynx in the DPS use very large areas as home ranges that incorporate landscape features that may be widely separated from one another to satisfy all of their life-history needs. In contrast to the extensive homogenous boreal forest found in the core of lynx range in northern Canada and Alaska, the southern terminus of the boreal forest type that extends into parts of the northern contiguous United States becomes transitional with other forest types—the Acadian forest in the Northeast (Seymour and Hunter 1992, pp. 1, 3), deciduous temperate forest in the Great Lakes, and subalpine forest in the west (Agee 2000, pp. 43-46). In this rule, 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).

Because of the transitional nature and patchy distribution of boreal forest in the contiguous United States, species that are specifically adapted to the classic boreal forest farther north, like the lynx, must contend with aspects of their habitat at the southern extent of the boreal forest for which they are not well-adapted. For example, southern transitional boreal forests often have lower landscape snowshoe hare densities than boreal forests further north (Wolff 1980, pp. 123-128; Buehler and Keith 1982, pp. 24, 28; Koehler 1990, p. 849; Koehler and Aubry 1994, p. 84). This requires lynx in the contiguous United States to incorporate more land area into their home ranges than lynx do in the north to acquire adequate food (Mowat

et al.

2000, pp. 265, 277-278). At some point, landscape hare densities become too low, making some areas incapable of supporting lynx survival and reproduction. Larger home ranges likely require more energy output associated with greater foraging effort (Apps 2000, p. 364) and possibly increased exposure to predation and other mortality factors than lynx face in the core of their range. All of this likely leads to lower reproductive output and tentative conservation status in many parts of the DPS relative to those in Canada and Alaska (Buskirk

et al.

2000b, p. 95).

Throughout the range of the DPS, lynx habitat occurs within boreal forest vegetation types that support high landscape densities of snowshoe hares and have deep snow for extended periods. In eastern North America, lynx distribution was strongly associated with areas of deep snowfall and large (40-mi

2

(100-km

2

)) landscapes that had been heavily cut and treated with herbicides and had a high proportion of regenerating forest (Hoving 2001, pp. 75, 143). Hoving

et al.

(2004, p. 291) concluded that 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. Second-order habitat selection in the Acadian forest region is influenced by hare density (a surrogate for early successional forest) and mature conifer forest, despite its association with low hare densities (Simons-Legaard

et al.

2013 pp. 573-574). In the Northern Rocky Mountains, lynx habitat relationships appear to be less tied to early successional forest stages; high lynx use and hare densities, especially in the critical winter season, occur in mature multistoried forest stands where conifer branches reach the snow surface and thereby provide hare forage (Squires

et al.

2006a, p. 15; Squires

et al.

2010, pp. 1653-1657; Berg

et al.

2012, entire).

Boreal forests used by lynx are generally cool, moist, and dominated by conifer tree species, primarily spruce and fir (Agee 2000, pp. 40-46; Aubry

et al.

2000, pp. 378-382; 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 heterogeneous mosaics of vegetative cover types and successional forest stages created by natural and human-caused disturbances (McKelvey

et al.

2000c, pp. 426-434). In many places 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 altered by clearcutting 15 to 25 years previously (Hoving

et al.

2004, p. 291; Simons-Legaard

et al.

2013, pp. 573-574). In other places, such as the Northern Rocky Mountains and Greater Yellowstone Area, mature multistoried conifer forests as well as dense regenerating conifer stands provide foraging habitat for lynx (Squires

et al.

2010, pp. 1648, 1653-1657; Berg

et al.

2012, entire).

The overall quality of the boreal forest landscape and the juxtaposition of stands of high-quality habitat within the landscape are important for both lynx and snowshoe hares in that both can influence connectivity or movements between habitat patches, availability of food and cover, and spatial structuring of populations or subpopulations (Hodges 2000b, pp. 184-195; McKelvey

et al.

2000c, pp. 431-432; Walker 2005, p. 79). For example, lynx foraging habitat must be near denning habitat to allow females to adequately provision dependent kittens, especially when the kittens are relatively immobile (Moen

et al.

2008a, p. 1507; Vashon

et al.

2012, p. 16). 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 patches containing dense vegetation (Walker 2005, p. 79; Lewis

et al.

2011, p. 565). 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 relatively gentle 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 areas of boreal forest landscapes to support their home ranges and to facilitate dispersal and exploratory travel. The size of lynx home ranges is 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.

2005, p. 11; Burdett

et al.

2007, p. 463). Reported average home range sizes vary greatly 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.

2004a, p. 13). Home range sizes of lynx introduced into Colorado averaged 29 mi

2

(75 km

2

) among reproductive females, 40 mi

2

(103 km

2

) among attending (reproductive) males, and 252 mi

2

(654 km

2

) among all non-reproductive lynx (Shenk 2008, pp. 1, 10). Based on data presented in Shenk (2008, p. 10) and combining reproductive and non-reproductive lynx, home range estimates for lynx in Colorado averaged 181 mi

2

(470 km

2

) for females and 106 mi

2

(273 km

2

) for males.

Forest Type Associations in the Contiguous United States

Maine

Stands of regenerating sapling (15-35 years old) spruce-fir forest that provide dense cover are preferred by both snowshoe hares and lynx in Maine (Robinson 2006, pp. 26-36; Vashon

et al.

2012, p. 15). Lynx were more likely to occur in large (40 mi

2

(100 km

2

)) landscapes with regenerating forest, and less likely to occur in landscapes with very recent clearcut or partial harvest, (Hoving

et al.

2004, pp. 291-292). Regenerating stands used by lynx generally develop 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 (15 to 24 feet (ft) (4.6 to 7.3 meters (m)) regenerating clearcut stands and older (11- to 21-year-old) partially harvested stands (Fuller

et al.

2007, pp. 1980, 1983-1985). At the home range scale, lynx also selected mature conifer forest (Simons-Legaard

et al.

2013, pp. 572-573). Lynx may use partial harvested and mature conifer stands associated with low hare densities because of increased ease of travel and prey access along the extensive edges with high-quality (regenerating clearcut) habitats (Simons-Legaard

et al.

2013 p. 574).

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 (

P. strobus

) mixed with aspen (

Populus

spp.), paper birch (

Betula papyrifera

), spruce, balsam fir (

A. balsamifera

) and jack pine (

P. banksiana

) (Minnesota Department of Natural Resources [Minnesota DNR] 2003, p. 2). Lynx habitats in Minnesota were associated with Lowland Conifer, Upland Conifer, Mixed Conifer, and Regenerating Forest cover types, with lynx selecting the latter because it provides snowshoe hare habitat (Moen

et al.

2008a, p. 1511; Moen

et al.

2008b, pp. 18-29). Moen

et al.

(2008b, pp. 23-25) reported that lynx also selected for the edges between different cover types, presumably because they could more efficiently capture hares along the edges between stands than in the dense interior understory of regenerating stands.

Northern Rocky Mountains (Idaho, Montana, and Northwestern Wyoming)

In the Northern Rocky Mountains, most lynx occurrences are associated with the Rocky Mountain Conifer Forest or Western Spruce-Fir Forest vegetative class (Kuchler 1964, p. 4; McKelvey

et al.

2000a, p. 246) and most occur above 4,101 ft (1,250 m) elevation (Aubry

et al.

2000, pp. 378-380; McKelvey

et al.

2000a, pp. 243-245). The dominant vegetation that constitutes lynx habitat in these areas is subalpine fir (

A. lasiocarpa

), Engelmann spruce (

P. engelmanii

) and lodgepole pine (

P. contorta

) (Aubry

et al.

2000, p. 379; Ruediger

et al.

2000, pp. 4-8—4-10). Within in the boreal forest landscape, lodgepole pine is seral to (i.e., is an earlier successional stage) subalpine fir and Engelmann spruce, which are climax forest habitat types. In winter, lynx preferentially used mature multistoried stands, predominantly spruce-fir, with dense horizontal cover and avoided clearcuts and large forest openings (Squires

et al.

2010, pp. 1648, 1653-1656). In summer, lynx also selected young stands with dense spruce-fir saplings, and avoidance of openings was not apparent (Squires

et al.

2010, pp. 1648, 1654-1655). Dry forest types (e.g., ponderosa pine (

Pinus ponderosa

), dry Douglas-fir (

Pseudotsuga menziesii

)) do not provide lynx habitat (Berg 2009, p. 20; Squires

et al.

2010, p. 1655).

Washington

In the North Cascades in Washington, most lynx occurrences were found above 4,101 ft (1,250 m) (McKelvey

et al.

2000a, p. 243, 2000d, p. 321; von Kienast 2003, p. 28, Table 2; Maletzke 2004, p. 17). In this area, lynx selected Engelmann spruce—subalpine fir forest cover types in winter (von Kienast 2003, p. 28; Maletzke 2004, pp. 16-17; Koehler

et al.

2008, p. 1518). As in the Northern Rockies, lodgepole pine is a dominant tree species in the earlier successional stages of these climax cover types. Seral (intermediate stage of ecological succession) 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). Douglas-fir and ponderosa pine forests, openings, recent burns, open canopy and understory cover, and steep slopes were all avoided habitat types (Koehler

et al.

2008, p. 1518).

Southern Rocky Mountains (Western Colorado, Northern New Mexico, Southern Wyoming)

Lynx introduced into Colorado used high-elevation mature Engelmann spruce/subalpine fir, mixed spruce/fir/aspen, and riparian/mixed riparian habitats in Subalpine and Upper Montane forest zones, and avoided lower elevation Montane forests of Douglas fir and ponderosa pine (Shenk 2008, pp.1-2, 12, 15; Devineau

et al.

2010, p. 525; Ivan 2011a, pp. 21, 27). However, it remains uncertain whether these habitats can sustain a viable lynx population over time (Shenk 2008, p. 16; Shenk 2010, pp. 2, 5-6, 11). Introduced lynx from Colorado also have wandered into mountainous areas of northern New Mexico, which contain relatively small and fragmented areas of similar high-elevation spruce/fir and cold mixed-conifer habitats (U.S. Forest Service 2009, pp. 5-10). No evidence exists that lynx occupied these areas historically; reproduction among introduced lynx that have traveled from Colorado into northern New Mexico has not been documented; and habitats in New Mexico are thought to be incapable of supporting a self-sustaining lynx population (U.S. Forest Service 2009, pp. 2, 10, 16-17).

Based on the information above, we identify large boreal forest landscapes that support high densities of snowshoe hares and have deep snow for extended periods to contain the physical and biological features needed to support and maintain lynx populations over time and which, therefore, are essential for the conservation of the lynx DPS.

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

Food (Snowshoe Hares)

Snowshoe hare density is the most important factor explaining the persistence of lynx populations (Steury and Murray 2004, p. 136). Snowshoe hare density differences among areas of boreal forest in the contiguous United States are also thought to explain many lynx distribution patterns historically and at present. While seemingly all of the physical aspects usually associated with lynx habitat may be present in a landscape, if snowshoe hare densities are inadequate to support reproduction, recruitment, and survival over time, lynx populations will not persist. Minimum landscape snowshoe hare densities necessary to maintain persistent, reproducing lynx populations across the range of the DPS have not been determined, although Ruggiero

et al.

(2000, pp. 446-447) suggested that at least 0.2 hares per ac (0.5 hares per ha) may be necessary. Landscape hare densities in areas known to support lynx home ranges in the contiguous United States were 0.26 hares per ac (0.64 hares per ha) in northeast Minnesota (Moen

et al.

2012, p. 352) and 0.30 hares per ac (0.74 hares per ha) in northern Maine (Simons-Legaard

et al.

2013, p. 574). Landscape hare density in Voyageurs National Park in northern Minnesota was estimated at 0.14 hares per ac (0.35 hares per ha) and did not support resident breeding lynx (Moen

et al.

2012, pp. 352-354). In northern Maine, areas with landscape hare densities less than 0.2 hares per ac (0.5 hares per ha) were not occupied by lynx (Simons-Legaard

et al.

2013, pp. 567, 575).

Steury and Murray (2004, entire) modeled lynx and snowshoe hare populations and predicted that a minimum of 0.4 to 0.7 hares per ac (1.1 to 1.8 hares per ha) would be required for persistence of a reintroduced lynx population in the portion of the lynx range in the contiguous United States. In areas used by introduced lynx in west-central Colorado, Zahratka and Shenk (2008, pp. 906, 910) reported hare densities that ranged from 0.03 to 0.5 hares per ac (0.08 to 1.32 hares per ha) in mature Engelmann spruce-subalpine fir stands and from 0.02 to 0.14 hares per ac (0.06 to 0.34 hares per ha) in mature lodgepole pine stands. In “purportedly good” hare habitat also in west-central Colorado in the area used by introduced lynx, Ivan (2011c, pp. iv-v, 71, 92) estimated summer hare densities of 0.08 to 0.27 hares per ac (0.2 to 0.66 hares per ha) in stands of “small” lodgepole, 0.004 to 0.01 hares per ac (0.01 to 0.03 hares per ha) in “medium” lodgepole, and 0.004 to 0.1 hares per ac (0.01 to 0.26 hares per ha) in spruce-fir stands.

The boreal forest landscape is naturally dynamic and usually contains a mosaic of forest stand successional stages. In some areas, particularly in the eastern portion of the DPS, stands that support high densities of snowshoe hares are of a young successional stage and are in a constant state of transition to other more mature stages. Conversely, 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 stages that are of lesser value as lynx foraging habitat (i.e., times when snowshoe hare abundance is low) or lynx denning habitat (Agee 2000, pp. 62-72; Buskirk

et al.

2000a, pp. 403-408) as part of a natural forest succession process. For example, a boreal forest stand where there has been recent disturbance, such as fire or timber harvest, resulting in little or no understory structure will support fewer snowshoe hares and, therefore, lower quality lynx foraging habitat. However, that temporarily low-quality stand would regenerate into higher-quality 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). The continuation of this naturally dynamic pattern of succession exhibited in boreal forests is crucial for lynx survival due to their dependence on intermediate successional stages in many areas. In places where lynx are dependent on mature forest stages, forest stand turnover still occurs, but on a longer time scale requiring the ability to recruit new mature forest stands as others are lost to fire, insect infestation, or human activities.

Forest management techniques that thin the understory may reduce habitat quality for hares and, thus, for lynx (Ruediger

et al.

2000, pp. 2-4—3-2; Hoving

et al.

2004, pp. 291-292; Homyack

et al.

2007, entire), at least temporarily (Griffin and Mills 2007, entire). Stands may continue to provide good 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) (Griffin and Mills 2007, entire). Thus, if the vegetation potential of the stand is appropriate, a stand that is not currently in a condition that supports abundant snowshoe hares for lynx foraging or coarse woody debris for den sites would improve as habitat for snowshoe hares (and thus lynx foraging) with time. Therefore, we consider lynx habitat to include forest areas with the potential, through natural succession, to produce high-quality snowshoe hare habitat, regardless of their current stage of forest succession.

Snowshoe hares feed on conifers, deciduous trees, and shrubs (Hodges 2000b, pp. 181-183), and they prefer boreal forest stands that have a dense horizontal understory to provide food, as well as cover and security from predators. 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). 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; Lewis

et al.

2011, pp. 561, 564-565). Generally, earlier successional forest stages provide a greater density of horizontal understory and support more 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, snowshoe hares can be abundant in mature forests with dense understories, particularly in the western part of the DPS range (Griffin 2004, pp. 53-54, 88; Hodges

et al.

2009, p. 876; Squires

et al.

2010, pp. 1648, 1653-1657; Berg

et al.

2012, pp. 1484-1488), and such mature forests may be a source of hares for other adjacent forest types (Griffin and Mills 2009, pp. 1492, 1495-1496).

In Maine, snowshoe hare densities were highest in regenerating softwood (spruce and fir) and mixed-wood stands with high conifer stem densities (Homyack 2003, p. 195; Fuller and Harrison 2005, pp. 716, 719; Robinson 2006, p. 69). However, when exploiting high-density hare habitats, lynx focused foraging efforts in stands with intermediate hare densities and structural complexity that occurred at the edges of the highest density habitat, suggesting that lynx must balance between hare abundance and accessibility (Fuller and Harrison 2010, pp. 1276-1277; Simons-Legaard

et al.

2013, p. 574). In northeastern Minnesota, lynx used areas with relatively higher proportions of coniferous forest, young (10- to 30-year-old) regenerating forest, and shrubby grassland, and these habitats supported the highest hare densities (McCann and Moen 2011, pp. 509, 515).

In montane and subalpine forests in northwest Montana, the highest snowshoe hare densities in summer were generally in younger stands with

dense forest structure, but winter hare densities were as high or higher in mature stands with dense understory forest structure (Griffin 2004, p. 53). In Montana in winter, hare and lynx used multistoried stands, often in older-age classes, where the tree boughs touch the snow surface but where the stem density is low (Squires

et al.

2006a, p. 15; Griffin and Mills 2009, pp. 1492, 1495-1496; Squires

et al.

2010, pp. 1648, 1653-1656). In the North Cascades of north-central Washington, snowshoe hare density was highest in 20-year-old lodgepole pine stands where the average density of trees and shrubs was 15,840 stems per ha (6,415 stems per ac) (Koehler 1990, pp. 847-848), and hare density was associated with large shrubs and saplings within a stand (Lewis

et al.

2011, pp. 561, 564-565). In western Wyoming, late-seral multistoried forests supported a greater abundance of snowshoe hares than regenerating even-aged forests (Berg

et al.

2012, p. 1). Similarly, in Yellowstone National Park, where hares were rare and patchily distributed, hare presence and relative abundance were linked to mature forest stands (Hodges

et al.

2009, p. 876). In western Colorado areas used by introduced lynx, Zahratka and Shenk (2008, pp. 906, 910) estimated higher hare densities in spruce-fir stands than in lodgepole pine, but Ivan (2011c, pp. iv, 71, 92) estimated hare densities as highest in stands of small lodgepole pine, intermediate in spruce-fir stands, and lowest in stands of medium lodgepole pine.

Habitats supporting abundant snowshoe hares must be present in a sufficient proportion (though not necessarily the majority) of the landscape to support a viable lynx population. Landscapes with more contiguous hare habitat, or where patches of high-quality habitat occur in a matrix with patches of similar quality, support more hares than fragmented habitats or those in which patches of hare habitat occur within a matrix of poor-quality habitat (Lewis

et al.

2011, p. 565). Broad-scale snowshoe hare density estimates are not available for all of the areas being proposed as lynx critical habitat. Available snowshoe hare density estimates are helpful in determining where snowshoe hares exist, but each estimate is specific to both a location and a point in time. Due to intrinsic, rapid fluctuations often seen in snowshoe hare populations, density estimates cannot be considered definitive for any particular area. If enough data were gathered for a specific area over several years, these data could be used to calculate an average density (with margins of error included). Lynx do not occur everywhere within the range of snowshoe hares in the contiguous United States (Bittner and Rongstad 1982, p. 146; McCord and Cardoza 1982, p. 729). This may be due to inadequate abundance, density, or spatial distribution of hares in some places, to the absence of snow conditions that would allow lynx to express a competitive advantage over other hare predators, or to a combination of these factors.

Based on the information above, we identify high densities of snowshoe hares broadly distributed across boreal forest landscapes to be a physical or biological feature needed to support and maintain lynx populations over time and which, therefore, is essential to the conservation of the lynx DPS.

Snow Conditions (Other Physiological Requirements)

Snow conditions also determine the distribution of lynx and snowshoe hares. Deep, fluffy snow conditions likely restrict potential lynx competitors such as bobcat or coyote from effectively encroaching on or hunting hares in winter lynx habitat. In addition to snow depth, other snow properties, including surface hardness or sinking depth, also influence lynx foraging success and, ultimately may be important factors in the spatial, ecological, and genetic structuring of the species (Stenseth

et al.

2004, entire). Gonzalez

et al.

(2007, pp. 4, 7) compared 496 lynx locations with snow cover over the period 1966-2005 and concluded that lynx require 4 months (December through March) of continuous winter snow coverage.

In eastern North America, snowfall was the strongest predictor of lynx occurrence at a regional scale (Hoving

et al.

2005, p. 746, Table 5), and lynx in the northeastern United States were most likely to occur in areas with a 10-year mean annual snowfall greater than 105 in (268 cm) (Hoving 2001, p. 75; Hoving

et al.

2005, p. 749). The Northern Superior Uplands section of northeast Minnesota, which supports a persistent lynx population, receives more of its precipitation as snow than any other part of the State, and has the longest period of snow cover and shortest growing season (Minnesota DNR 2003, p. 2). Average 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 Cascade and Northern Rocky Mountains is limited because few weather stations in these regions have measured snow fall or snow depth over time. An important consideration in mountainous areas is that topography strongly influences local snow conditions. For example, in the Cascades, annual snowfall averaged 121 in (307 cm) at Mazama, WA (elevation 2,106 ft (642 m)), and 15 in (38 cm) at Omak, WA (elevation 1,299 ft (396 m)) (Western Regional Climate Center 2013). In western Montana areas that support lynx populations, annual snowfall averaged 90 in (229 cm) in Troy (elevation 1,950 ft (594 m)) and 120 in (305 cm) at Seeley Lake (elevation 4,200 ft (1,280 m)) (Western Regional Climate Center 2013).

Based on the information above, we identify winter conditions that provide and maintain deep, fluffy snow for extended periods in boreal forest landscapes to be a physical or biological feature needed to support and maintain lynx populations over time and which, therefore, are essential to the conservation of the lynx DPS.

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.

In northern Maine, 12 of 26 natal dens occurred in conifer-dominated sapling stands, and 5 dens were found in mature or mixed multistoried forest stands dominated by conifers (Organ

et al.

2008, p. 1515). Modeling sub-stand characteristics of these 26 dens determined that 2 variables, tip-up mounds of blown-down trees and visual obscurity at 5 m from the den, were most useful for predicting lynx den-site selection in managed forests (Organ

et al.

2008, p. 1514). Lynx essentially selected dense cover in a cover-rich area for denning. Denning habitat was provided by blowdown, deadfalls, and root wads. Coarse woody debris alone was not a useful predictor of lynx den-site selection, despite its abundance, and denning habitat was not considered limiting in northwest Maine (Organ

et al.

2008, p. 1516). Den sites in Maine often occurred at the interface of two stands of different ages or in dense regenerating conifer stands, suggesting that females select den sites near prey sources to minimize time spent away

from kittens while foraging (Vashon

et al.

2012, p. 16).

In northern Minnesota, structural components of forests, such as blowdown and deadfalls, appear to be more important than forest cover type in determining lynx denning habitat (Interagency Lynx Biology Team 2013, p. 46). Most den sites in Minnesota were found in blowdown and were associated with small patches of uplands surrounded by low-lying wetland areas (Moen and Burdett 2009, pp. 5, 11). Although lowland conifer cover types appeared to provide the forest structure used most often for denning in northern Minnesota (Moen

et al.

2008a, p. 1510), other forest cover types were used if they contained recent blowdowns (Moen and Burdett 2009, p. 16). Very dense horizontal cover in the immediate vicinity of the den site also appeared to be a determinant (Moen and Burdett 2009, p. 16). Female lynx foraged within approximately 1.2-1.8 mi (2-3 km) of den sites when kittens were at the den; at the scale of the foraging radius around a den site, landscape composition contained more lowland conifer, upland conifer, and regenerating forest than did home ranges (Moen

et al.

2008a, p. 1507). Denning habitat does not appear to be limiting in northern Minnesota (Moen and Burdett 2009, p. 16).

In northwestern Montana, lynx generally denned in mature spruce-fir forests among downed logs or root wads of wind-thrown trees in areas with abundant coarse woody debris and dense understories with high horizontal cover in the immediate areas around dens (Squires

et al.

2004a, Table 3; Squires

et al.

2008, pp. 1497, 1501-1505). Few dens were located in young regenerating or thinned stands with discontinuous canopies (Squires

et al.

2008, p. 1497). Many dens had northeasterly aspects and were farther from forest edges than random expectation (Squires

et al.

2008, p. 1497).

In the North Cascades, Washington, lynx denned in mature (older than 250 years) stands with an overstory of Engelmann 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). Den site availability, although not thought to be limiting for lynx populations in the DPS (Moen

et al.

2008a, p. 1512; Organ

et al.

2008, pp. 1514, 1516-1517; Squires

et al.

2008, p. 1505), is an essential component of the boreal forest landscapes that lynx need to satisfy a key life-history process (reproduction).

Introduced lynx in Colorado denned at higher elevations and on steeper slopes compared to general use areas, with den sites tending to have northerly aspects and dense understories of coarse woody debris (Shenk 2008, p. 2).

Based on the information above, we identify denning habitat as described above to be a physical or biological feature needed to support and maintain lynx populations over time and which, therefore, is essential to the conservation of the lynx DPS.

Habitats Protected From Disturbance or Representative of the Historic Geographical and Ecological Distributions of the Species

Climate Change

Our analyses under the Act include consideration of ongoing and projected changes in climate. The terms “climate” and “climate change” are defined by the Intergovernmental Panel on Climate Change (IPCC). In 2007, the IPCC released its Fourth Assessment Report, which represents the current scientific consensus on global and regional climate change and the best scientific data available in this rapidly changing field. “Climate” refers to the mean and variability of different types of weather conditions over time, with 30 years being a typical period for such measurements, although shorter or longer periods also may be used (IPCC 2007a, p. 78). The term “climate change” thus refers to a change in the mean or variability of one or more measures of climate (e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2007a, p. 78). Various types of changes in climate can have direct or indirect effects on species. These effects may be positive, neutral, or negative and they may change over time, depending on the species and other relevant considerations, such as the effects of interactions of climate with other variables (e.g., habitat fragmentation) (IPCC 2007a, pp. 8-14, 18-19). In our analyses, we use our expert judgment to weigh relevant information, including uncertainty, in our consideration of various aspects of climate change.

Previous IPCC assessments concluded that temperatures across the globe have increased by about 1.8 °Fahrenheit (F) (1 °Celsius (C)) over the last century (IPCC 2001, p. 7). The IPCC projection for eastern and western North America within the range of the lynx DPS is climate warming of 1.8 °F (1 °C) to 5.4 °F (3 °C) by the year 2050 (IPCC 2007b, p. 889). The range of warming projected over the next century runs from 3.6 °F (2 °C) to 10.8 °F (6 °C) for North America, with warming higher than this average in areas that are inland, northerly, or mountainous. The IPCC concludes that continued warming in North America, with lower snow accumulation and earlier spring snowmelt, is very likely (IPCC 2007b, p. 887). Climate history and projections from regional climate models for regions within the lynx DPS corroborate global models indicating that both eastern and western North America, including all portions of the lynx DPS, have warmed in the last century and are likely to warm 1.8 °F (1 °C) to 5.4 °F (3 °C) by the year 2050 (IPCC 2007b, p. 889). For example, in the Northern Rocky Mountains at Glacier National Park, mean summer temperatures have increased 3.0 °F (1.66 °C) between 1910 and 1980 (Hall and Fagre 2003, pp. 134-137) resulting in lower snowpack, earlier spring melt, and distributional shifts in vegetation (Hall and Fagre 2003, pp. 138-139; Fagre 2005, pp. 4-9). These changes are predicted to continue and accelerate under future climate scenarios (Hall and Fagre 2003, Fig. 7). An analysis of potential snow cover under a range of IPCC future climate scenarios and modeling of vegetation using a dynamic vegetation model indicates that potential lynx habitat could decrease by as much as two-thirds in the contiguous United States by the end of this century (Gonzalez

et al.

2007, pp. 4, 7-8, 10, 13-14).

Across their worldwide distribution, lynx are dependent on deep snow that persists for long periods of time. Warmer winter temperatures are reducing snow pack in all portions of the lynx DPS through a combination of a higher proportion of precipitation falling as rain and higher rates of snowmelt during winter (Hamlet and Lettenmaier 1999, p. 1609; Brown 2000, p. 2347; Hoving 2001, pp. 73-75; Mote 2003, p. 3-1; Christensen

et al.

2004, p. 347; Knowles

et al.

2006, pp. 4548-4549). This trend is expected to continue with future warming (Hamlet and Lettenmaier 1999, p. 1611; Christensen

et al.

2004, p. 347; Mote

et al.

2005, p. 48; IPCC 2007b, p. 850). The IPCC (2007b, p. 850) concludes that “snow season length and snow depth are very likely to decrease in most of North America except in the northernmost part of Canada where maximum snow depth is likely to increase.” Shifts in the timing of the initiation of spring runoff toward earlier dates in western North America are also well documented (Hamlet and

Lettenmaier 1999, p. 1609; Brown 2000, p. 2347; Cayan

et al.

2001, pp. 409-410; Christensen

et al.

2004, p. 347; Mote

et al.

2005, p. 41; Knowles

et al.

2006, p. 4554). In addition, a feedback effect causes the loss of snow cover due to the reflective nature of snow and the relative heat-absorbing properties of non-snow-covered ground. This feedback effect leads to the highest magnitude of warming occurring at the interface of snow-covered and exposed areas, increasing the rate at which melting occurs in spring (Groisman

et al.

1994a, pp. 1637-1648; Groisman

et al.

1994b, pp. 198-200). This effect has led to the average date of peak snowmelt to shift three weeks earlier in spring in the Intermountain West (Fagre 2005, p. 4).

Snow accumulation and duration are expected to decline generally in the geographic areas that contain the central and eastern portion of the lynx DPS (IPCC 2007c, p. 891; Burns

et al.

2009, p. 31). Due to the importance to lynx of prolonged periods of deep fluffy snow, current habitats that lose this feature would decline in value for lynx (Hoving 2001, p. 73; Carroll 2007, p. 1092; Gonzalez

et al.

2007, entire). Reduced snow depth and duration may reduce lynx's competitive advantage over bobcats, which have similar ecology to lynx but are not as well-adapted to hunting hares in deep fluffy snow (Hoving 2001, pp. 23-24; Carroll 2007, p. 1102; Interagency Lynx Biology Team 2013, p. 69, 71).

Changes in temperature and rainfall patterns are expected to shift the distribution of ecosystems northward and up mountain slopes (McDonald and Brown 1992, pp. 411-412; Danby and Hik 2007, pp. 358-359; IPCC 2007c, pp. 230, 232). As climate changes over a landscape, the ecosystems that support lynx are likely to shift, tracking the change of temperature, but with a time lag depending on the ability of individual plant and animal species to migrate (McDonald and Brown 1992, pp. 413-414; Hall and Fagre 2003, p. 138; Peterson 2003, p. 652). In the contiguous United States, researchers expect that lynx in mountainous habitat will, to some extent, track climate changes by using higher elevations on mountain slopes, assuming that vegetation communities supportive of lynx and hare habitats also move upslope (Gonzalez

et al.

2007, p. 7).

Future of Lynx Habitat

In 2003, we determined that climate change was not a threat to lynx within the contiguous U.S. DPS 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., Knowles

et al.

2006, pp. 4545-4559; Carroll 2007, pp. 1098-1102; Danby and Hik 2007, pp. 358-359; Gonzalez

et al.

2007, entire; Burns

et al.

2009, p. 31; Johnston

et al.

2012, pp. 6-13), and much of this new information suggests that climate change is likely to be a significant issue of concern for the future conservation of the lynx DPS. These studies predict lynx distribution and habitat are likely to shift upward in elevation within its currently occupied range and recede northward as temperatures increase (Gonzalez

et al.

2007, pp. 7, 13-14, 19; Jacobson

et al.

2009, pp. 26-27, 30-31; Vashon

et al.

2012, pp. 60, 64; Interagency Lynx Biology Team 2013, p. 69). Climate modeling suggests that lynx habitat and populations are anticipated to decline accordingly (Carroll 2007, pp. 1098-1102) and may disappear completely from parts of the range of the DPS by the end of this century (Johnston

et al.

2012, pp. 6-13). Climate change is expected to substantially reduce the amount and quality of lynx habitat in the contiguous United States, with patches of high-quality habitat becoming smaller, more fragmented, and more isolated (Carroll 2007, pp. 1099-1100; Johnston

et al.

2012, p. 11). Remaining lynx populations would likely be smaller than at present and, because of small population size and increased isolation, populations would likely be more vulnerable to stochastic environmental and demographic events (Carroll 2007, pp. 1100-1103).

Aside from predicted elevational and latitudinal shifts in areas currently occupied by lynx, we are aware of no models that predict specific areas not currently of value for lynx that will become so as a result of climate-induced changes (e.g., Johnston

et al.

2012, p. 11). Therefore, at this time, we find it appropriate to propose critical habitat for the lynx only in areas occupied by the DPS that currently contain the physical and biological features essential to the conservation of the lynx. Although it is not within our authority to designate critical habitat in Canada (in the event that the range of lynx recedes northward out of the contiguous United States), the revised critical habitat units in this proposed rule include, to the extent practicable, higher elevation habitats within the range of the DPS that would facilitate long-term lynx adaptation to an elevational shift in habitat should one occur. As climate change scenarios and ecosystem responses become more regionally certain, revisions to critical habitat may be necessary to accommodate shifts in the range of the essential physical and biological features and any corresponding shift in the range of lynx in the contiguous United States.

Primary Constituent Element for Canada Lynx

Under the Act and its implementing regulations, we are required to identify the physical or biological features essential to the conservation of lynx in areas occupied at the time of listing, focusing on the features' primary constituent elements (PCEs). We consider PCEs to be the elements of physical or biological features that, when laid out in the appropriate quantity and spatial arrangement to provide for a species' life-history processes, are essential to the conservation of the species.

Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain the species' life-history processes, we determine, as we did in the 2009 final critical habitat rule, that the PCE specific to lynx in the contiguous United States 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, which include dense understories of young trees, shrubs or overhanging boughs that protrude above the snow, and mature multistoried stands with conifer boughs touching the snow surface;

(b) Winter conditions that provide and maintain deep fluffy snow for extended periods of time;

(c) Sites for denning that have 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.

With this proposed designation of critical habitat, we intend to identify the physical or biological features essential to the conservation of the species, through the identification of the appropriate quantity and spatial arrangement of the features' PCE sufficient to support the recovery of the species. For lynx, the distinction

between areas that may contain

some

of each of the physical and biological features described above and areas that have

all

of the physical and biological features, each in adequate quantities

and

spatial arrangements to support populations, is very important for the reasons discussed below.

Many places in the contiguous United States have (1) some amount of boreal forest supporting a mosaic of successional stages, (a) snowshoe hares and their habitats, (b) deep, fluffy snow for extended periods, (c) denning habitat, and (d) other habitat types interspersed among boreal forest patches, but which do not and cannot support lynx populations. That is, not all boreal forest landscapes supporting a mosaic of differing successional forest stages contain the physical and biological features essential to lynx in adequate quantities and spatial arrangements on the landscape to support lynx populations over time. Lynx may occasionally (even regularly, if intermittently) occur temporarily in places that do not contain all of the elements of the PCE, especially during “irruptions” of lynx into the northern contiguous United States following hare population crashes in Canada (as described above under

Species Information

and below under

Criteria Used To Identify Critical Habitat

). However, because lynx reproduction and recruitment in such places, if any occur at all, do not offset mortality and dispersal, these areas are likely population “sinks,” and as such do not contribute to lynx conservation or recovery. We have determined that these population “sink” areas do not contain the PCE and, therefore, are not essential to the conservation and recovery of the lynx DPS.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain features which are essential to the conservation of the species and which may require special management considerations or protection.

The need for specific management direction and conservation measures for lynx was recognized during development of the interagency Lynx Conservation Assessment and Strategy (LCAS; Ruediger

et al.

2000, entire). The U.S. Forest Service (USFS), Bureau of Land Management (BLM), National Park Service, and the Service developed the LCAS 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. The overall goals of the 2000 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 identified an inclusive list of 17 potential risk factors for lynx or lynx habitat that could be addressed under programs, practices, and activities within the authority and jurisdiction of Federal land management agencies. The risks identified in the LCAS were based on effects to individual lynx, lynx populations, or to lynx habitat.

Potential risk factors the LCAS addressed that may affect lynx productivity included: timber management, wildland fire management, recreation, forest/backcountry roads and trails, livestock grazing, and other human developments. Potential risk factors the LCAS addressed that may affect lynx mortality included: trapping, predator control, incidental or illegal shooting, and competition and predation as influenced by human activities and highways. Potential risk factors the LCAS addressed that may affect lynx movement included: 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 included: fragmentation and degradation of lynx refugia, lynx movement and dispersal across shrub-steppe habitats, and habitat degradation by nonnative and invasive plant species.

With the listing of the lynx DPS in 2000, Federal agencies across the contiguous U.S. range of the lynx were required to consult with the Service on actions that may affect lynx. The LCAS assisted Federal agencies in planning activities and projects in ways that benefit lynx or avoid adverse impacts to lynx or lynx habitat. In most cases, if projects were designed that failed to meet the standards in the LCAS, the biologists using the LCAS would arrive at an adverse effect determination for lynx. The 2000 LCAS used the best information available at the time to ensure that the appropriate mosaic of habitat would be provided for lynx conservation on Federal lands. Although the LCAS was written specifically for Federal lands, many of the conservation measures were considered equally applicable to non-Federal lands.

A Conservation Agreement between the USFS and the Service (U.S. Forest Service and U.S. Fish and Wildlife Service 2000, entire) and a similar Agreement between the BLM and the Service (Bureau of Land Management and U.S. Fish and Wildlife Service 2000, entire) committed the USFS and BLM to use the LCAS in determining the effects of actions on lynx until Forest and Land Management Plans were amended or revised to adequately conserve lynx. A programmatic biological opinion pursuant to section 7 of the Act confirmed the adequacy of the LCAS and its conservation measures to conserve lynx, and concluded that USFS and BLM land management plans, as implemented in accordance with the Conservation Agreements, would not jeopardize the continued existence of lynx (U.S. Fish and Wildlife Service 2000, entire).

Lynx conservation depends on management that supports boreal forest landscapes of sufficient size to encompass the temporal and spatial changes in habitat and snowshoe hare populations to support interbreeding lynx populations over time. At the time it was written, the LCAS recommended the most appropriate level of management or protection for lynx. The LCAS conservation measures addressed risk factors affecting lynx habitat and lynx productivity and were designed to be implemented at the scale necessary to conserve lynx. This level of management is appropriate for Federal lands because they account for the majority of high-quality lynx habitat in the contiguous United States (except for Maine), and also because the inadequacy, at the time of listing, of regulatory mechanisms to conserve lynx on these lands was the primary reason for listing the lynx as a threatened species under the Act.

After the LCAS was written, research on lynx, hares, and their habitats and distributions continued throughout the range of the DPS. The Service and land management agencies recognized that, as new scientific information became available, it should supplement the LCAS and be taken into account by land managers. The USFS considered such new information when it proposed to revise 18 Forest Plans under a programmatic plan amendment called the Northern Rocky Mountain Lynx Amendment (NRLA) (U.S. Forest Service 2007). Some of the LCAS standards were changed to guidelines because the Service determined that some risk factors were not negatively affecting the lynx DPS as a whole. For example, after publication of the LCAS, lynx studied in the contiguous United States were shown to use a variety of sites and conditions for denning, and

den site availability is not believed to be a limiting factor for lynx in the DPS (U.S. Fish and Wildlife Service 2007, pp. 48-49; Interagency Lynx Biology Team 2013, p. 30). Similarly, after evaluating Bunnell

et al.

(2006, entire) and Kolbe

et al.

(2007, entire), the Service determined that the best information available did not indicate that compacted snow routes increased competition from other species to levels that adversely impact lynx populations in the NRLA area (U.S. Fish and Wildlife Service 2007, pp. 53-55). Also since the LCAS was written, new information revealed the importance of multistoried stands for lynx in western areas (Squires

et al.

2006a, p. 15); based on this, the USFS adopted a standard in the NRLA not identified in the LCAS for conserving such stands.

In addition to diverging from the standards in the LCAS because of new information, the NRLA also deviated from the LCAS by allowing additional fuels-reduction projects in areas within the wildlands-urban-interface (WUI). In our analysis of the NRLA, we determined that the management in the NRLA area would provide for the recovery of lynx in these areas by addressing the major reason we listed the lynx in 2000—the lack of guidance for conservation of lynx in Federal land management plans. Consultation under section 7 of the Act was completed for the NRLA in 2007, and it is now official land management direction for the National Forests that adopted it. In 2008, the USFS and the Service coordinated on the development of the similar Southern Rocky Mountains Lynx Amendment to guide section 7 consultation and conservation of lynx introduced into Colorado and their potential habitats on seven National Forests in Colorado and southern Wyoming (U.S. Fish and Wildlife Service 2008, entire; U.S. Forest Service 2008a, entire).

Federal agencies across most of the range of the DPS have amended or revised land management plans to include specific management direction to conserve lynx and lynx habitat (Interagency Lynx Biology Team 2013, p. 88). This direction was developed in accordance with the National Forest Management Act (NFMA) of 1976 and the regulations that implement the statute (36 CFR 219.22), which requires public review and comment as part of the decision-making process. The USFS has completed such amendments or revisions to Land and Resource Management Plans in its Eastern, Northern, Rocky Mountain, and Intermountain regions. In the Pacific Northwest Region, forest plans for national forests with lynx habitat are currently being revised (Interagency Lynx Biology Team 2013, p. 4).

To address the substantial volume of new information on lynx, hares, and their habitats and distributions that has accumulated from more than a decade of continuing research throughout the range of the DPS, the LCAS, completed in January of 2000 and revised in August of 2000, was again revised in 2013 (Interagency Lynx Biology Team 2013, entire). The current revision synthesizes all the available research relevant to lynx, their primary prey, and anthropogenic influences on the conservation of lynx in the contiguous United States. Most USFS Land and Resource Management Plans within the current range of lynx have been formally amended or revised to incorporate lynx and hare conservation standards and guidelines. Standards and guidelines were primarily based on those in the 2000 LCAS, but many Forests used the LCAS to develop goals, objectives, and standards and guidelines formulated or adapted for specific geographic areas or Forest units. Therefore, the Lynx Biology Team deemed it appropriate to abandon the use of prescriptive measures such as those in the 2000 LCAS, and in the 2013 revision provide recommended conservation measures to be considered in project planning and implementation and which may help inform future amendments or revisions of USFS forest plans.

The 2013 LCAS revision presents the most current source of such information and will continue to inform the special management considerations necessary for conserving lynx on Federal lands. Notably, the 2013 revision concludes that recent studies in the contiguous United States generally suggest that lynx are rarer and more patchily distributed in the western U.S. and Great Lakes regions, and more abundant in Maine, than previously thought (Interagency Lynx Biology Team 2013, p. 23). It recommends focusing limited conservation resources on those “. . . relatively limited areas that support persistent lynx populations and have evidence of recent reproduction, with less stringent protection and greater flexibility given in areas that only support lynx intermittently” (Interagency Lynx Biology Team 2013, p. 2). By proposing critical habitat only in areas that contain the PCE (have

all

physical and biological features in adequate quantities and spatial arrangements), the Service, with this rule, adopts the LCAS recommendation to focus conservation in areas capable of supporting lynx populations over time.

The LCAS was developed to provide a consistent and effective approach to conserve lynx on Federal lands in the conterminous United States. In northern New England, the only place the LCAS would apply is on Federal land in the White Mountain National Forest. However, in northern New England, most lynx habitat is on private commercial timber lands, and lynx populations there occur in extensive boreal forest landscapes where large, contiguous stands of young, regenerating spruce-fir habitat are prevalent (due to past clearcut timber harvest) and support high densities of snowshoe hares. Although lynx and hare habitats were likely created historically by natural forest disturbances (e.g., fire, insects and disease, and windthrow), the current extensive habitats in northern Maine are the result of large-scale industrial forest management. Maintaining lynx populations there will require forest management practices that produce extensive stands supporting high hare densities into the future. The Service developed Canada Lynx Habitat Management Guidelines for Maine (McCollough 2007, entire), which specify the special management—recommendations on land use, forest conditions, landscape conditions, and silviculture requirements—needed to support lynx populations based on the best available science (see discussion of Healthy Forest Reserve Program under Exclusions, below, for further details).

Assuring adequate management of most lynx habitat on private lands in northern New England has been limited success. Extensive clearcutting in the 1970s and 1980s to salvage conifers damaged by spruce budworm created much of the habitat currently used by lynx. The Maine Forest Practices Act of 1989 regulated clearcuts, resulting in a shift in timber-harvesting practices toward a greater reliance on partial harvesting, which supports lower hare densities (Robinson 2006, entire). Without forest management planning, likely silviculture scenarios are expected to cause declines of 55-65 percent in lynx habitat and populations by 2032 (Simons 2009, p. 217). Four northern Maine landowners with collective ownership of approximately 8.5 percent of occupied lynx habitat have developed lynx forest management plans through the Natural Resource Conservation Service's Healthy Forest Reserve Program. These landowners commit to employ the Service's lynx habitat management guidelines (McCollough 2007, entire), which include greater use of even-aged

silviculture that creates large patches of high-quality hare habitat and landscape hare densities that will continue to support lynx. All other private lands occupied by lynx in Maine currently lack specific forest management plans for lynx, indicating a continuing need for special management considerations there.

Criteria Used To Identify Critical Habitat

As required by section 4(b)(2) of the Act, we use the best scientific data available to designate critical habitat. We review available information pertaining to the habitat requirements of the species. In accordance with the Act and its implementing regulation at 50 CFR 424.12(e), we consider whether designating additional areas—outside those currently occupied as well as those occupied at the time of listing—are necessary to ensure the conservation of the species.

We do not currently propose to designate any areas outside the geographic area occupied by lynx at the time of listing because we have determined that occupied areas are sufficient for the conservation of the lynx DPS.

To determine those specific areas occupied by the species at the time it was listed on which are found those physical or biological features essential to the conservation of the species, as required by section 3(5)(a)(i) of the Act, we reviewed the approach to the conservation of the lynx provided in the LCAS (Ruggiero

et al.

2000, entire; Interagency Lynx Biology Team 2013, entire); the Recovery Outline (U.S. Fish and Wildlife Service 2005, entire); information from State, Federal and Tribal agencies; and information from academia and private organizations that have collected scientific data on lynx. We reviewed available information that pertains to the habitat requirements of lynx and its principal prey, the snowshoe hare. This information included data in reports submitted by researchers holding recovery permits under section 10(a)(1)(A) of the Act; research published in peer-reviewed articles or presented in academic theses; agency reports and unpublished data; and various Geographic Information System (GIS) coverages (e.g., land cover type information, land ownership information, snow depth information, topographic information, locations of lynx obtained from radio- or GPS-collars and locations of lynx confirmed via DNA analysis or other verified records).

In proposing critical habitat for the lynx, we used the best scientific data available to evaluate areas that possess appropriate quantities and spatial arrangements of the physical and biological features essential to the conservation of the DPS and that may require special management considerations or protection. In evaluating areas as critical habitat, we first conducted a two-part analysis: (1) We relied on information used during listing of the species, and any available newer information, to delineate the geographic area occupied by the species at the time of listing, and (2) we used the best available scientific information to determine which occupied areas contain the physical and biological features in adequate quantities and spatial arrangements to support lynx populations over time, thus demonstrating that they are essential to the conservation of the lynx.

To delineate critical habitat for lynx, we must be able to distinguish, across the extensive range of the species in the contiguous United States, areas that contain all essential physical and biological features in adequate quantities and spatial distributions to support lynx populations over time (areas with the PCE, as described above under “Primary Constituent Element for Canada Lynx”) from other areas that may contain some or all of the features but in inadequate quantities and/or spatial arrangements of one or more feature (and which, therefore, by definition do not contain the PCE). However, the scientific literature does not confer precisely what quantities and spatial arrangements of the physical and biological features are needed to support lynx populations throughout the range of the DPS. We lack range-wide site-specific information or tools that would allow us to analyze boreal forests across much of the range of the DPS and determine which specific areas contain the spatial and temporal mosaic of habitats and hare densities that lynx populations need to persist.

Delineating critical habitat for lynx is complicated by a number of factors related to (1) the animals' biology and population dynamics; (2) the biology and population dynamics of its primary prey, the snowshoe hare; (3) the patchily distributed, temporally and spatially dynamic successional habitat features that shift continually across landscapes, and which drive populations of both lynx and hares at the southern peripheries of both species' ranges; (4) our imperfect understanding of the above factors; and (5) the resulting difficulty in determining with certainty and quantifying which specific habitat features, in what specific amounts and spatial and temporal arrangements, are necessary to provide the boreal forest mosaic essential to lynx conservation. The task is further complicated by an imperfect historical record of lynx occurrence in the contiguous United States. Finally (but importantly), the differences between areas capable of supporting lynx populations over time and other areas that look like they should, but do not, are often subtle and cannot be distinguished over broad areas using traditional vegetation/habitat mapping, remote sensing (aerial photos, satellite data), or available habitat modeling techniques (e.g., see Ivan 2011a, p. 27).

As described above (see

Distribution

and

Biology

), lynx populations throughout most of their range are irruptive. In central Canada where they inhabit a large, relatively homogenous boreal forest landscape, lynx respond quickly to cyclic fluctuations in hare populations. When hares are abundant, lynx respond with increased productivity and survival and, therefore, increased population sizes (Slough and Mowat 1996, pp. 955-956; Mowat

et al.

2000, pp. 266, 272). Typically, after hare numbers peak, they begin to decline rapidly and dramatically, forcing large numbers of lynx to disperse—to abandon home ranges in areas with dwindling prey bases no longer capable of supporting the large number of lynx that resulted from the earlier prey abundance (Slough and Mowat 1996, pp. 956-957; Mowat

et al.

2000, pp. 291-294). These periodic mass dispersal events (irruptions) appear to start at the core of the species' range in Canada and radiate outward (McKelvey

et al.

2000a, p. 239). At the southern periphery of the lynx's range, these events sometimes result in large numbers of lynx dispersing into a variety of habitats in some areas of the northern contiguous United States in search of adequate food resources (Thiel 1987, entire; McKelvey

et al.

2000a, pp. 239-242). Some of these dispersing lynx survive and reestablish home ranges elsewhere, but many die en route, often soon after initiating dispersal (Mowat

et al.

2000, p. 293), and some appear to remain temporarily in areas not capable of supporting all of their life-history needs over time (Thiel 1987, entire).

Canadian populations of lynx have historically been the most reliable source for lynx populations in many areas of the contiguous United States, tending to replenish them within the DPS about every ten years as the lynx/hare cycle ebbs and flows (McKelvey

et al.

2000a, entire). These events can be pictured as a “wave” of lynx that occasionally washes over many of the northern tier of States. Over time the wave recedes, leaving remnant lynx populations or “puddles” of lynx in a

variety of habitats. These puddles of lynx shrink over time as many lynx perish in inhospitable habitats or disperse elsewhere in search of adequate hare densities. When these waves recede, lynx may disappear abruptly from areas of unsuitable habitat or more gradually from suboptimal or marginal habitats. In both cases, lynx perish in or leave many of the places where they occurred temporarily because the habitats in such places, due to insufficient prey densities or inadequacy of one or more other physical or biological features, are incapable of supporting them over time. In a few places in the northern contiguous United States, in landscapes with high snowshoe hare densities and adequate quantities and spatial arrangements of other essential physical and biological features, the puddles tend to persist. It is these remnant “puddle” areas that demonstrate the capacity to support lynx population resiliency—the ability of lynx to persist through lows in their own populations and those of their primary prey—that we have determined are essential to conservation of the contiguous U.S. lynx DPS.

In terms of lynx conservation, it is important to distinguish between areas that support lynx populations over time (the lasting “puddles”) and areas in which lynx may occasionally and temporarily (even if somewhat regularly) occur during and for some time after population irruptions (the temporary or shrinking “puddles”). The former are likely “source” subpopulations within the lynx metapopulation. In addition to their ability to persist through lows in hare and lynx numbers, those areas, during times of hare abundance, produce excess lynx that may either subsequently bolster the local population or disperse into adjacent areas, should habitats and hare numbers in those areas become favorable. The latter areas are likely “sinks”—places where lynx may occasionally occur temporarily but where reproduction and recruitment, if any occur at all, are unlikely to offset mortality. Such areas do not produce excess lynx and, therefore, do not contribute to the health and stability of the metapopulation.

Lynx are wide-ranging animals that regularly make long-distance movements through both suitable and unsuitable habitats. They also are habitat and prey specialists, inferring natural selection pressures favoring the ability to identify, locate, and occupy habitats conducive to survival and reproduction. The historic record shows that lynx occurred only occasionally in some parts of the southern periphery of its range in the contiguous United States during and for variable lag times after the wave-like population irruptions described above, with long periods of apparently complete absence between irruptions (McKelvey

et al.

2000a, entire). This finding suggests that lynx dispersing from areas where hare numbers were declining arrived at many such places looking for but not finding the physical and biological features they needed to survive over the long term (Mowat

et al.

2000, p. 293). Additionally, lynx were listed under the Act because regulatory mechanisms at the time were deemed inadequate to conserve lynx habitats in the places they did occur, not because of any documented population decline or range contraction in the contiguous United States. For the reasons given above, we conclude it is unlikely that there are areas within the DPS range that contain the PCE (i.e., adequate amounts and spatial arrangements of all essential physical and biological features) that lynx have been unable to locate and occupy. We further conclude that areas supporting persistent lynx populations within the range of the DPS are unlikely to have remained undetected.

Finally, the Act indicates that the function of critical habitat is to provide for the recovery of the species. We designate critical habitat in areas that contain, based on our assessment of the best data available to us, the physical and biological features in the appropriate quantities and spatial arrangements (the PCE), to provide for the conservation of the species. For some species, critical habitat may include unoccupied areas if the currently occupied areas are not sufficient to recover the species. For other species, critical habitat may be a subset of the occupied areas, if the occupied areas have differences in quality that relate to their ability to contribute meaningfully to recovery of the species. The Act does not require that we designate critical habitat in every area that has some components or some amount of the PCE, nor does it require that we demonstrate that all other areas lack the PCE. We make these determinations on a case-by-case basis based upon the best information available as to what the species needs for recovery.

By specifically allowing revisions to critical habitat designations if and when new information becomes available, the Act recognizes the potential limitations of the best available information at any point in time. For lynx, we have determined that not all areas where lynx occasionally occur are necessary for recovery. We believe that lynx recovery in the contiguous United States can be accomplished by conserving high-quality habitat occupied by persistent lynx populations across the range of the DPS, and addressing the threats to lynx in those areas.

In summary, lynx have a demonstrated ability to disperse large distances in search of favorable habitats. Further, natural selection theory implies the ability of lynx to locate and occupy areas conducive to their survival and population viability. Nonetheless, due to inherent swings in densities of their primary prey, lynx regularly occur temporarily in habitats that are not capable of supporting populations over time, usually during irruptions after cyclic hare population crashes in Canada. In proposing critical habitat for lynx, it is essential to distinguish between areas capable of supporting populations over time (areas with all essential physical and biological features in adequate quantities and spatial arrangements and which, therefore, demonstrably contain the PCE) and areas that may have some or all of the features but with inadequate quantities and/or spatial arrangements of one or more of them (and which, therefore, do not contain the PCE). Exactly how much of each of the physical and biological features must be present and specifically how each must be spatially arranged within boreal forest landscapes to support lynx populations over time is unknown. In the absence of site-specific information, we do not have tools or techniques (e.g., remote sensing or vegetation mapping technologies of adequate resolution) that would allow us to distinguish across broad landscapes throughout all of the range of the DPS between those areas that contain the PCE and other areas that contain the physical and biological features but in inadequate quantity and/or spatial arrangement. Nonetheless, we use the best available information to identify where the physical and biological features occur in adequate quantity and spatial arrangement to provide for the conservation of the species. Within this context, we developed the strategy described below for identifying, delineating, and proposing to designate critical habitat for the contiguous U.S. DPS of the Canada lynx.

The focus of our strategy in considering lands for designation as critical habitat is on boreal forest landscapes of sufficient size to encompass the temporal and spatial changes in habitat and snowshoe hare populations to support interbreeding

lynx populations over time. These factors are included in the PCE for lynx. As defined in the Recovery Outline, areas that meet these criteria and have recent evidence of reproduction are considered “core areas” for lynx (U.S. Fish and Wildlife Service 2005, pp. 3-4).

In determining the geographic area occupied by the species at the time of listing, we used data providing verified evidence of lynx occurrence. We eliminated areas from consideration in two ways: (1) areas outside the known historical range and (2) data older than 1995 were not considered valid to our assessment of areas occupied by lynx populations at the time of listing. We used data on the known historical range of the lynx (e.g., McKelvey

et al.

2000a, pp. 207-232; Hoving

et al.

2003, entire) to eliminate areas outside the historical range of the species.

We then focused on records since 1995 to ensure that this critical habitat designation is based on the data that most closely represent the current status of lynx in the contiguous United States and the geographical area known to be occupied by the species at the time of listing. Although the average lifespan of a wild lynx is not known, we assumed that a lynx born in 1995 could have been alive in 2000 or 2003, when the final listing rule and the clarification of findings were published. Data after 1995 were considered a valid indicator of occupancy at the time of listing. Recent verified lynx occurrence records were provided by Federal research entities, State wildlife agencies, academic researchers, Tribes, and private individuals or organizations.

We used only verified lynx records, because we wanted to rely on the best available data to evaluate specific areas and their features for critical habitat designation. The reliability of lynx occurrence reports can be questionable because the bobcat, a common species in much of the range of the lynx DPS, can easily be confused with the lynx. Additionally, many surveys are conducted by snow tracking in which correct identification of tracks can be difficult because of variable conditions affecting the quality of the track and variable expertise of the tracker. Our definition of a verified lynx record is based on McKelvey

et al.

(2000a, p. 209): (1) an animal (live or dead) in hand or observed closely by a person knowledgeable in lynx identification, (2) genetic (DNA) confirmation, (3) snow tracks only when confirmed by genetic analysis (e.g., McKelvey

et al.

2006, entire), or (4) location data from radio or GPS-collared lynx. Documentation of lynx reproduction consists of lynx kittens in hand, or observed with the mother by someone knowledgeable in lynx identification, or snow tracks demonstrating family groups traveling together, as identified by a person highly knowledgeable in identification of carnivore tracks. However, we made an exception and accepted snow track data from Maine, New Hampshire, and Vermont because of the stringent protocols, the confirmation of lynx tracks by trained, highly-qualified biologists, and the minimal number of species in the area with which lynx tracks could be misidentified (Maine Dept. of Inland Fisheries and Wildlife 2003, entire).

To define critical habitat according to section 3(5)(A) of the Act, we then delineated, within the geographical area occupied by the species at the time of listing, areas containing physical and biological features essential to the conservation of the lynx. The adequacy of the quantities and spatial arrangements of the physical and biological features (as defined above) essential to the conservation of the DPS is informed by the recovery outline for the species (as discussed below), the nature of the threats in a particular geographic area, and the conservation needs for the species in a particular geographic area.

In the North Cascades and Northern Rockies, the features essential to the conservation of lynx, the majority of lynx records, and the boreal forest types are typically, though not always, found above 4,000 ft (1,219 m) in elevation (McKelvey

et al.

2000b, pp. 243-245; McAllister

et al.

2000, entire). Thus, we limited the delineation of critical habitat to lands above this elevation unless we had habitat data indicating that high-quality habitat exists below this elevation. Additionally, in the North Cascades, features essential to the conservation of the lynx and the majority of the lynx records occur east of the crest of the Cascade Mountains.

Application of the Criteria to the Southern Rocky Mountains; Certain National Forests in Idaho and Montana; and Northern New Hampshire, Northern Vermont, and Eastern and Western Maine

As described above under Previous Federal Actions, the District Court for the District of Montana found several flaws with our 2009 critical habitat designation for lynx. The following section discusses the issues raised by the court. We also provide an evaluation of the recently documented small breeding populations of lynx in northern New Hampsire, northern Vermont, and eastern and western Maine.

Colorado and the Southern Rocky Mountains

The Montana District Court found that we failed in our 2009 designation to determine whether “areas occupied by lynx in Colorado possess the physical and biological features essential to the conservation of the species.”

In the Recovery Outline, we defined six core areas for lynx as those having

both

persistent verified records of lynx occurrence over time

and

recent evidence of reproduction (U.S. Fish and Wildlife Service 2005, pp. 3-5, 20-21). We also defined the Southern Rocky Mountains of Colorado and southern Wyoming as a “provisional” core area because it contained an introduced lynx population that had demonstrated reproduction (U.S. Fish and Wildlife Service 2005, p. 4). “Provisional” means: “accepted or adopted tentatively; conditional; or temporary.” In our 2009 critical habitat designation, after careful evaluation of the historic record of verified lynx occurrence in Colorado and the Southern Rockies, we determined that there was no compelling evidence that the area had ever supported lynx populations over time and that, therefore, it did not likely contain the PCE and did not meet our criteria for designating critical habitat (74 FR 8641). For reasons that are described in more detail below, the available data do not support that Colorado and the Southern Rockies contain the physical and biological features essential to lynx in adequate quantities, quality, and spatial arrangements to support lynx populations over time, and we provide what evidence is available to determine whether the area, or any parts of it, contain the PCE.

In 1999, just prior to lynx being listed under the Act, the Colorado Division of Wildlife (now Colorado Parks and Wildlife (CPW)) began an intensive effort to establish a lynx population in Colorado, eventually releasing 218 wild-caught Alaskan and Canadian lynx from 1999 to 2006 (Devineau

et al.

2010, p. 524). At least 122 (56 percent) of the introduced lynx died by June of 2010 (Shenk 2010, pp. 1, 5), but others survived and established home ranges in Colorado, produced kittens in some years, and now are distributed throughout forested areas of western Colorado. Some lynx from this introduced population have also traveled into northern New Mexico, eastern Utah, and southern and western Wyoming, though no reproduction outside of Colorado has been documented by these dispersers.

The CPW has determined the lynx introduction effort to be a success based

on attainment of several benchmarks (e.g., high post-release survival, low adult mortality rates, successful reproduction, recruitment equal to or greater than mortality over time; Ivan 2011a, p. 21 and 2011b, p. 11), but acknowledges that the future persistence of the population is uncertain and hinges on the assumption that patterns of annual reproduction and survival observed as of 2010 repeat themselves during the next 20 or more years (Shenk 2008, p. 16; Shenk 2010, pp. 2, 5-6, 11). However, CPW has discontinued the intensive monitoring necessary to determine if these patterns of reproduction and survival will persist over that time (Colorado Parks and Wildlife 2012, p. 1), instead embarking on a passive monitoring program to detect lynx presence (Ivan 2011b, entire).

Although parts of Colorado and the Southern Rocky Mountains clearly contain some (perhaps all) of the physical and biological features lynx need, available evidence does not indicate that the area, or any parts of it, contain the features in the quantities, quality, and spatial arrangement necessary to provide for the conservation of the species (i.e., to support lynx populations over the long term). The Southern Rocky Mountains (western Colorado, northern New Mexico, and southern Wyoming) are on the southern limit of the species' range and contain marginal lynx habitat (74 FR 8619), are disjunct from lynx habitats in the United States and Canada (McKelvey

et al.

2000a, p. 230; 68 FR 40090; Devineau

et al.

2010, p. 525; Interagency Lynx Biology Team 2013, pp. 50, 54), and have patchily distributed habitat that limits snowshoe hare abundance (Interagency Lynx Biology team 2013, p. 54). The nearest lynx population occurs in the Greater Yellowstone Area, which supports a small, low density population also disjunct from other lynx populations and which is unlikely to regularly supply dispersing lynx to the Southern Rockies. We previously determined that the Southern Rockies' distance and isolation from other lynx populations and habitats substantially reduce the potential for lynx from northern populations to naturally augment or colonize the area, that the immigration necessary to maintain a local lynx population is, therefore, naturally precluded, and that the contribution of the Southern Rockies to the persistence of lynx in the contiguous United States is presumably minimal (68 FR 40100-40101).

Dolbeer and Clark (1975, p. 539) estimated 0.30 hares per ac (0.73 hares per ha) on their study area in Summit County in central Colorado. Reed

et al.

(1999, unpublished, as cited by Hodges (2000b, p. 185)) reported hare densities in Colorado ranging from 0.02 to 0.19 hares per ac (0.05 to 0.46 hares per ha). In areas used by introduced lynx in west-central Colorado, Zahratka and Shenk (2008, pp. 906, 910) reported hare densities that ranged from 0.03 to 0.5 hares per ac (0.08 to 1.32 hares per ha) in mature Engelmann spruce-subalpine fir stands and from 0.02 to 0.14 hares per ac (0.06 to 0.34 hares per ha) in mature lodgepole pine stands. The authors cautioned against comparing their results to other hare density estimates, as their use of the “mean maximum distance moved” method may have underestimated effective area trapped (Zahratka and Shenk 2008, p. 911), potentially resulting in overestimates of hare density. In “purportedly good” hare habitat also in west-central Colorado in the area used by introduced lynx, Ivan (2011c, pp. iv-v, 71, 92) estimated summer hare densities of 0.08 to 0.27 hares per ac (0.2 to 0.66 hares per ha) in stands of “small” lodgepole pine, 0.004 to 0.01 hares per ac (0.01 to 0.03 hares per ha) in “medium” lodgepole pine, and 0.004 to 0.1 hares per ac (0.01 to 0.26 hares per ha) in spruce-fir stands. The author reported that hare densities were less than 0.4 hares per ac (< 1.0 hare per ha) in all stand types and all seasons and, in most cases, were less than 0.12 hares per ac (0.3 hares per ha), and no combination of survival and recruitment estimates from any stand type in any year would result in a self-sustaining hare population, though hare recruitment may have been underestimated (Ivan 2011c, pp. 95, 99).

Ruggiero

et al.

(2000, pp. 446-447) concluded that a snowshoe hare density greater than 0.2 hares per ac (0.5 hares per ha) may be necessary for lynx persistence. Steury and Murray (2004, pp. 127, 137) modeled lynx and hare populations and determined that a hare density of 0.4-0.7 hares per ac (1.1-1.8 hares per ha) would be needed for persistence of lynx translocated (i.e., introduced or reintroduced) to the southern portion of the species' range. Most hare density estimates for Colorado are well below those thought necessary to support an introduced lynx population over time (Steury and Murray 2004, entire), and many, even from areas considered “good” hare habitat, are lower than the density Ruggiero

et al.

(2000, pp. 446-447) considered necessary for lynx persistence.

The generally low hare densities reported in most cases in what is considered good hare habitat in western Colorado and the very large home ranges (181 mi

2

(470 km

2

) for females and 106 mi

2

(273 km

2

) for males) reported by Shenk (2008, pp. 1, 10) suggest that even the best potential lynx habitat in the Southern Rocky Mountains is marginal and unlikely to support lynx populations over time. Some of the lynx introduced into Colorado have dispersed into mountainous areas of northern New Mexico, which contain relatively small and fragmented areas of similar high-elevation spruce/fir and cold mixed-conifer habitats (U.S. Forest Service 2009, pp. 5-10). No evidence exists that lynx occupied these areas historically; no reproduction has been documented among introduced lynx that have traveled from Colorado into northern New Mexico; and habitats in New Mexico are thought to be incapable of supporting a self-sustaining lynx population (U.S. Forest Service 2009, pp. 2, 10, 16-17). The lack of connectivity with northern lynx populations (McKelvey

et al.

2000a, p. 230; Devineau

et al.

2010, p. 525; Interagency Lynx Biology Team 2013, pp. 50, 54), which is considered necessary for the maintenance and conservation of lynx populations in the contiguous United States (Interagency Lynx Biology Team 2013, pp. 42, 47, 54, 60, 65), further suggests that lynx in the Southern Rockies, in the absence of continued translocations or introductions of lynx, are unlikely to receive the demographic and genetic exchange needed to maintain lynx populations over time.

For these reasons, the Service has determined that the Southern Rocky Mountains likely do not possess the physical and biological features essential to lynx in sufficient quantities, quality, and spatial arrangement to sustain lynx populations over time. Wildlife introductions are, by their nature, experiments whose fates are uncertain. However, it is always our goal for such efforts to be successful and, where possible, contribute to recovery of listed species. If Colorado's introduction effort is successful (i.e., if recruitment equals or exceeds combined mortality and emigration over the next 20 years (Shenk 2010, pp. 2, 5-6, 11)), it could

contribute

to recovery by providing an additional buffer against threats to the DPS. The potential contribution of Colorado to lynx recovery does not mean, however, that the habitat there is essential for the conservation of the DPS. In other words, the lynx population in Colorado is beneficial, but not essential, for

recovery. Therefore, we find that the habitat in Colorado and elsewhere in the Southern Rocky Mountains does not contain the essential physical and biological features of lynx habitat, is not essential for the conservation of the lynx DPS, and we are not proposing to designate critical habitat for the lynx DPS in the Southern Rockies. However, as a listed species, it should be noted that lynx in the Southern Rockies are afforded protection pursuant to sections 7(a)(2) and 9 of the Act. Section 7(a)(2) requires Federal agencies, when undertaking, funding, or permitting actions that may affect listed species to consult with the Service, and to ensure that the implementation of such actions do not result in jeopardy to the species. Toward that end and pursuant to section 7 of the Act, the Service may recommend measures to minimize the effects (including incidental take) of the Federal action upon listed species.

National Forests in Idaho and Montana

The Montana District Court ordered the Service to determine specifically whether lands in the Clearwater and Nez Perce National Forests in Idaho, the Bitterroot National Forest in Idaho and Montana, the Beaverhead-Deerlodge National Forest in Montana, and additional parts of the Helena and Lolo National Forests (outside the areas currently proposed for designation) in Montana contain the physical and biological features essential for the conservation of the DPS. Although each of these areas clearly contain some (and perhaps all) of the physical and biological features lynx need, for the reasons discussed below we find no evidence that any of the areas contain the elements in adequate quantities, quality, and spatial arrangements to support lynx populations over time. We provide evidence, where available, that these areas were not occupied by lynx at the time of listing and are not currently occupied by lynx populations, and we summarize relevant survey results, all of which indicate that lynx do not occupy these areas or that the areas are lacking in either quantity or spatial arrangement (or both) of one or more of the essential features. Therefore, we determine that these areas do not contain the physical and biological features in adequate quantities, quality, and spatial arrangement, are not essential to the conservation of the lynx, and as a result these areas do not meet the definition of critical habitat and subsequently are not being proposed.

The historical record does not suggest that these areas (outside those portions of the Helena and Lolo National Forests proposed for designation as critical habitat) ever supported lynx populations (McKelvey

et al.

2000a, pp. 224-227). In the Recovery Outline, the Service classified these as “secondary areas” because they lacked evidence of lynx reproduction (U.S. Fish and Wildlife Service 2005, pp. 4, 21). As described in detail below, recent surveys for lynx in many of these areas have failed to detect lynx presence, and the available evidence suggests these areas occasionally may provide temporary habitat for transient lynx dispersing from established lynx populations in the Northern Rocky Mountains of Canada, Idaho, and Montana, but that they likely do not contain all physical and biological features in adequate quantities and spatial arrangements to support lynx populations over time.

There is no evidence that the Beaverhead-Deerlodge, Bitterroot, and Nez Perce National Forests were occupied by lynx at the time of listing, nor that they are currently occupied by lynx populations. To date, surveys on these National Forests, which have been conducted according to established protocols, have failed to detect presence of any individual lynx, and they provide no indication of the presence of lynx populations. Surveys described below were conducted according to National Lynx Survey (McKelvey

et al.

1999, entire), and winter snow-tracking survey (Squires

et al.

2004b, entire) protocols. Snow-tracking surveys in particular are highly effective at detecting lynx, even when only a few animals inhabit the survey area (Ulizio

et al.

2007, p. 5; Squires

et al.

2012, pp. 215, 219-222).

On the Beaverhead-Deerlodge National Forest, National Lynx Survey efforts in 1999-2001 detected no lynx (U.S. Forest Service 2002a, entire and 2002b, entire). During 2001-2005, in surveys designed to detect presence of lynx and wolverines, 11,220 mi (17,950 km) of winter snow-tracking surveys and trap route checks in the Anaconda-Pintler, Beaverhead, Flint Creek and Pioneer mountain ranges on the Beaverhead-Deerlodge National Forest detected only a single “putative” lynx track, and no verified tracks (Squires

et al.

2003, p. 4; Squires

et al.

2006b, p. 15). Additional recent snow tracking surveys (Berg 2009, entire) also failed to detect any lynx, and the author concluded that, although some pockets of habitat appeared to support high densities of snowshoe hares, “[m]ost of the [Beaverhead-Deerlodge National Forest] was and appeared to be dry lodgepole pine, which likely is not good lynx habitat . . .” (Berg 2009, p. 20). During May and June of 2009, hair snares (642 snare-nights) and remote cameras (319 camera-nights) deployed in the Boulder, Flint Creek, and Pioneer mountain ranges also failed to detect any lynx (Porco 2009, entire). Additional hair snare surveys in summer 2012 similarly failed to detect lynx (Pilgrim and Schwartz 2013, entire; U.S. Forest Service 2013a, entire). Snow-tracking surveys designed to detect presence of multiple forest carnivores, including lynx, conducted by the Idaho Department of Fish and Game from 2004 to 2006 detected no lynx in the Beaverhead Mountains Section, just west of the Beaverhead-Deerlodge National Forest (Patton 2006, pp. 20-21, Table 11).

On the Bitterroot National Forest, National Lynx Survey efforts in 2000-2002 and 2010-2011 detected no lynx (U.S. Forest Service 2000, entire, 2002c, entire, 2003a, entire, 2003b, entire; Pilgrim 2010, entire; Shortsleeve 2013, pers. comm.). Snow-tracking surveys designed to detect presence of multiple forest carnivores, including lynx, conducted by the Idaho Department of Fish and Game from 2004 to 2006 detected no lynx in the Bitterroot Mountains Section (Patton 2006, pp. 20-21, Table 11). Additionally, among 223 vegetation plots sampled in 2010-2012 on the Forest, only 30 (16.1%) met minimum horizontal cover standards for snowshoe hare/lynx habitat (U.S. Forest Service 2012, unpublished data).

On the Nez Perce National Forest, winter snow-tracking surveys covering 448 mi (721 km) in 2007 did not detect any lynx (Ulizio

et al.

2007, entire). The authors concluded that (1) these surveys very likely would have detected the presence of a lynx population if one occurred on the Forest, (2) that the failure to detect lynx suggests that a lynx population does not inhabit the surveyed portion of the Forest, and (3) “[h]istorical sightings. . . may be the result of transient lynx moving through the forest, but the infrequency of such reports suggests lynx are incidental to the area” (Ulizio

et al.

2007, p. 5). Neither a partial hare-snare survey conducted in 2008 (though at fewer stations than recommended by the protocol) nor a partial snow-tracking survey conducted in 2009 (also less extensive than protocol) detected presence of lynx on the Forest. Snow-tracking surveys conducted according to established protocols and covering 553 mi (890 km) of forest roads were completed in 2013; these surveys also failed to detect presence of any lynx on the Nez Perce National Forest (U.S. Forest Service 2013b, pp. 3-7). Snow-tracking surveys designed to detect presence of multiple forest carnivores, including lynx, conducted by the Idaho

Department of Fish and Game from 2004 to 2006 detected no lynx in the Clearwater Region, including parts of the Nez Perce National Forest (Patton 2006, p. 9, Table 2).

The paucity of verified historical records of lynx occurrence in these three National Forests, and the absence of recent verified records, despite surveys designed to detect lynx presence, suggest these areas may rarely and temporarily support transient dispersing lynx (McKelvey

et al.

2000a, pp. 224-227; Ulizio

et al.

2007, p. 5). Based on these surveys, historical records of lynx occurrence, the vegetation sampling data described above (U.S. Forest Service 2012, unpublished data), and expert opinion on habitat quality described above (Ulizio

et al.

2007, p. 5), the Service has determined that habitats on these three National Forests are not occupied by lynx populations and do not contain the physical and biological features in the appropriate quantity and spatial arrangement to be essential to lynx conservation. Additionally, we have determined that these areas are not essential to the conservation of the lynx DPS. Because we find that these areas do not meet the definition of critical habitat we are not proposing to designate the Bitterroot, Beaverhead-Deerlodge, and Nez Perce National Forests as critical habitat.

We recognize that all of the Clearwater and Lolo National Forests, and parts of the Helena National Forest (except for the disjunct Big Belt and Elkhorn mountain ranges) are considered as “occupied” by lynx for purposes of consultations under section 7 of the Act. Occupancy in the context of section 7 consultation is intended to inform the “may be present” standard under section 7 and does not infer the presence of lynx populations or that habitats in these areas contain the physical and biological features essential to

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