[Federal Register: January 10, 2007 (Volume 72, Number 6)]
[Rules and Regulations]               
[Page 1186-1189]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AV17

Endangered and Threatened Wildlife and Plants; Clarification of 
Significant Portion of the Range for the Contiguous United States 
Distinct Population Segment of the Canada Lynx

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Clarification of findings.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service) provide a 
clarification of the finding we made in support of the final rule that 
listed the contiguous U.S. Distinct Population Segment of the Canada 
lynx (Lynx canadensis) (lynx) as threatened. In that rule, we found 
that, ``collectively, the Northeast, Great Lakes, and Southern Rockies 
do not constitute a significant portion of the range of the DPS 
(Distinct Population Segment).'' In response to a court order, we now 
clarify that finding.

ADDRESSES: The complete file for this clarification is available for 
inspection, by appointment, during normal business hours at the Montana 
Ecological Services Office, 585 Shepard Way, Helena, MT 59601 
(telephone 406/449-5225).

FOR FURTHER INFORMATION CONTACT: Mark Wilson, Field Supervisor, Montana 
Fish and Wildlife Office, at the above address (telephone 406/449-

SUPPLEMENTARY INFORMATION: The Service listed the Canada lynx, 
hereafter referred to as lynx, as threatened on March 24, 2000 (65 FR 
16052). After listing the lynx as threatened, plaintiffs in the case of 
Defenders of Wildlife v. Kempthorne (Civil Action No. 00-2996 (GK)) 
initiated action in Federal District Court challenging the listing of 
the lynx as threatened. On December 26, 2002, the Court issued a 
Memorandum of Opinion and Order to have the Service explain our 2000 
finding that ``[c]ollectively the Northeast, Great Lakes and Southern 
Rockies do not constitute a significant portion of the [lynx] DPS.'' 
Pursuant to that order, the Service published a notice of remanded 
determination and clarification of our 2000 finding on July 3, 2003 (68 
FR 40075). In that notice, the Service attempted to address the court's 
order and issued a new finding that the lynx is not endangered 
throughout a significant portion of its range. Plaintiffs subsequently 
brought further action claiming that the Service violated the court's 
2002 order.
    On September 29, 2006, the Court issued another Memorandum of 
Opinion and Order remanding the same portion of the Service's March 24, 
2000, determination of status for the lynx. The court remanded the 
finding so that ``the Service may clearly and specifically address the 
finding it was ordered to explain three years ago: That `[c]ollectively 
the Northeast, Great Lakes, and Southern Rockies do not constitute a 
significant portion of the [lynx] DPS' (Order at 3).'' This finding 
appeared in the final rule that listed the contiguous U.S. DPS of the 
lynx as threatened (65 FR 16052; March 24, 2000). Because the court 
remanded the 2000 listing determination for further explanation of how 
the Service at that time reached its conclusion the Northeast, Great 
Lakes, and Southern Rockies do not constitute a significant portion of 
the lynx DPS, the following discussion addresses the basis for the 
Service's decision in 2000. The conclusions reached in 2000, and the 
basis for those conclusions, do not necessarily represent the Service's 
current views, given new information regarding the lynx as well as the 
evolving views of the courts and the Service regarding the meaning of 
the definitions of ``endangered species'' and ``threatened species.'' 
In fact, when the Service completed the first remand decision, it did 
not reiterate its conclusion from 2000 on this issue; instead, it based 
its new conclusion on a different line of reasoning. The Service 
recently requested that the Office of the Solicitor examine the 
definition of ``endangered species.'' As a result, the explanation of 
the Service's rational for its decision in 2000 provided here may not 
reflect how the Service will apply the definition of ``endangered 
species'' in the future.

[[Page 1187]]


    The Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et 
seq.) (Act), defines an ``endangered'' species as one that is ``in 
danger of extinction throughout all or a significant portion of its 
range'' and a ``threatened'' species as one that is ``likely to become 
endangered within the foreseeable future throughout all or a 
significant portion of its range'' (16 U.S.C. 1532(6); 16 U.S.C. 
1532(20); 50 CFR 424.02(e) and (m)). The Secretary of the Interior 
``shall publish in the Federal Register a list of all species 
determined * * * to be endangered species and * * * threatened species. 
Each list shall refer to the species contained therein by scientific 
and common name or names, if any, specify with respect to [each] such 
species over what portion of its range it is endangered or threatened, 
and specify any critical habitat within such range'' (16 U.S.C. 
    Apart from the statutory and regulatory definitions of 
``threatened'' and ``endangered,'' no formal guidance shaped the 
Service's analysis in the 2000 final listing rule of what was to be 
considered when evaluating the ``significance'' of any particular area 
of a species'' range. Furthermore, at that time there was no case law 
concerning what should be considered in a determination of a 
``significant portion'' of a species'' range. Since publication of the 
2000 final listing rule, several courts have interpreted the meaning of 
``significant portion of its range.'' See, Defenders of Wildlife v. 
Norton 258 F. 3d 1136 (9th Cir. 2001); Center for Biological Diversity 
v. Norton, 411 F. Supp. 2d 1271 (D.N.M. 2005); Southwester Center for 
Biological Diversity v. Norton, 2002 U.S. Dist. Lexis 13661 (D.D.C. 
July 29, 2002); Defenders of Wildlife v. Norton, 239 F. Supp. 2d 9 
(D.D.C. 2002; Center for Biological Diversity v. Lohn, 296 F Supp. 2d 
1223 (W.D. Wash. 2003); Environmental Protection Information Ctr. v. 
National Marine Fisheries Service, Civ. No. 02-5401 ED2 (N.O. Cal. Mar. 
1, 2004); Defenders of Wildlife v. Norton, Civ. No. 99-02072 HHK 
(D.D.C. Dec. 13, 2001); Defenders of Wildlife v. Secretary, U.S. 
Department of Interior, 354 F. Supp. 2d 1156 (D. Or. 2005); National 
Wildlife Federation v. Norton, 386 F. Supp. 2d 553 (D. Vt. 2005).
    The historical and current range of the Canada lynx north of the 
contiguous United States includes Alaska and that part of Canada that 
extends from the Yukon and Northwest Territories south across the 
border with the contiguous United States and east to New Brunswick and 
Nova Scotia. In the contiguous United States, the current (and 
historical) range of the lynx extends into four geographic areas: the 
Northeast, including the States of Maine, New Hampshire, Vermont, and 
New York; the western Great Lakes, including the States of Minnesota, 
Michigan, and Wisconsin; the Southern Rocky Mountains in the States of 
Colorado and Wyoming; and the Northern Rocky Mountains/Cascades, 
including the States of Montana, Washington, Idaho, Utah, Wyoming, and 
Oregon. It is notable that the range of the lynx has not been radically 
contracted or reduced.
    When the Service listed the lynx, we followed the Policy Regarding 
the Recognition of Distinct Vertebrate Population Segments Under the 
Endangered Species Act (DPS Policy) to evaluate whether the lynx 
population in the contiguous United States constituted a DPS and thus 
was a listable entity under the Act (61 FR 4722; February 7, 1996). 
Under the DPS Policy, a population must meet two criteria to qualify as 
a DPS: First, the population in question must be determined to be 
discrete from other members of the taxon, and second, the population in 
question must be determined to be significant to the taxon. In this 
case, the taxon is the species Lynx canadensis, whose range extends 
throughout Alaska and Canada into the contiguous United States, as 
described above.
    The DPS Policy allows the use of international boundaries to define 
discreteness if there are differences in control of exploitation, 
management of habitat, conservation status, or regulatory mechanisms 
between the two countries. In the final rule, we determined that, 
because Canada had no overarching forest practices legislation 
governing management of national lands and/or providing for 
consideration of wildlife habitat requirements, and also because of 
lynx harvest regulations that exist in Canadian Provinces, the 
differences in management of lynx and lynx habitat between Canada and 
the United States were sufficient to enable us to use the international 
boundary between Canada and the contiguous United States to delineate 
the DPS according to the discreteness criterion (65 FR 16060; March 24, 
    In the final rule, we found that lynx in the contiguous United 
States are significant to the taxon under the DPS Policy because of the 
climatic, vegetative, and ecological differences between lynx habitat 
in the contiguous United States and that in northern latitudes in 
Canada and Alaska. In the contiguous United States, lynx distribution 
occurs in habitats at the southern extent of the range of the boreal 
forest, comprising subalpine coniferous forest in the West and southern 
boreal forest/hardwoods in the East (for ease of description, we use 
the general term ``southern boreal forest'' to describe lynx habitat in 
the contiguous United States); whereas in Canada and Alaska, lynx 
inhabit the classic boreal forest ecosystem known as the taiga. 
Furthermore, lynx and snowshoe hare population dynamics in the 
contiguous United States are different from those in northern Canada 
and Alaska (65 FR 16060; March 24, 2000).
    Based on the above factors, we determined that the lynx population 
in the contiguous United States was discrete and significant under the 
DPS Policy and, therefore, qualified as a listable entity under the Act 
(65 FR 16060; March 24, 2000).
    We then further considered whether individually any of the four 
geographic areas (Northeast, Great Lakes, Southern Rockies, and 
Northern Rockies/Cascades) that make up the current range of the lynx 
within the contiguous United States fulfilled the DPS Policy criteria 
(65 FR 16060; March 24, 2000). We determined that, within the 
contiguous United States, each of these areas was discrete from the 
others. However, we found none of the areas to be significant.
    Because of the extensive range of the lynx within the contiguous 
U.S. DPS, we structured the 2000 final listing to describe the status 
of the species in the four geographic areas (Northeast, Great Lakes, 
Southern Rockies, and Northern Rockies/Cascades) (65 FR 16060; March 
24, 2000). We determined ``that collectively, the Northeast, Great 
Lakes, and Southern Rockies regions do not constitute a significant 
portion of the DPS range.'' The final rule prefaced this finding with 
the following discussion:

    Within the contiguous United States, the relative importance of 
each region to the persistence of the DPS varies. The Northern 
Rockies/Cascades Region supports the largest amount of lynx habitat 
and has the strongest evidence of persistent occurrence of resident 
lynx populations, both historically and currently. In the Northeast 
(where resident lynx populations continue to persist) and Southern 
Rockies regions, the amount of lynx habitat is naturally limited and 
does not contribute substantially to the persistence of the 
contiguous United States DPS. Much of the habitat in the Great Lakes 
Region is naturally marginal and may not support prey densities 
sufficient to sustain lynx populations. As such, the Great Lakes 
Region does not contribute substantially to the persistence of the 
contiguous United States DPS. We conclude the Northern Rockies/
Cascades Region is the primary region

[[Page 1188]]

necessary to support the long-term existence of the contiguous 
United States DPS (65 FR 16061, 16082).

    In summary, the Service determined that, collectively, the 
Northeast, Great Lakes, and Southern Rockies regions do not constitute 
a significant portion of the range of the DPS because (1) the amount of 
lynx habitat in the Northeast and Southern Rockies is naturally limited 
and (2) much of the habitat in the Great Lakes Region is marginal and 
may not support prey densities sufficient to sustain lynx.
    The analysis in the 2000 final listing rule concerning 
``significance'' specifically addressed and focused on the biological 
``significance'' of areas of habitat within the range of the lynx (65 
FR 16060; March 24, 2000). The biological context that we viewed as 
important in the 2000 final listing rule included the distribution of 
lynx and the contribution of each area to the life-history needs of the 
species. For example, the final listing rule found that lynx exist in 
areas with forest types and vegetation that can support snowshoe hares, 
the primary prey of lynx, and where cover exists for denning. Lynx are 
highly specialized predators of snowshoe hares. Both lynx and snowshoe 
hares have evolved to survive in areas that receive fluffy and/or deep 
snow. Snowshoe hares prefer dense forest understories for forage, cover 
to escape from predators, and protection during extreme weather (Wolfe 
et al. 1982; Monthey 1986; Hodges 1999a, 1999b). Lynx use large woody 
debris, such as downed logs and windfalls, to provide denning sites 
with security and thermal cover for kittens (McCord and Cardoza 1982; 
Koehler 1990; Koehler and Brittell 1990; Squires and Laurion 1999; J. 
Organ, U.S. Fish and Wildlife Service, in litt. 1999).
    In the 2000 final listing rule, we evaluated ``significance'' 
primarily in this biological context. In that rule, we expressed the 
belief (which we still maintain) that significance should not be 
determined based on the size of an area alone. We considered the 
ability of the area to support populations needed for recovery to be 
the primary consideration. We did not consider sizable area with poor-
quality habitat for the species or prey limitations to be significant 
from a biological perspective.
    Thus, we viewed a significant portion to be an important portion, 
not just a geographically large portion. ``Important,'' in turn, we 
viewed in the larger context of the Act. The primary purpose of the Act 
is to conserve imperiled species. See 16 U.S.C. Sec.  1531(b). 
Moreover, the use of science in pursuing this goal is a theme in the 
Act. In particular, in identifying endangered and threatened species, 
the Act requires that we use ``the best scientific and commercial data 
available.'' Id. Sec.  16 U.S.C. 1533(b)(1)(A). In this context, we 
concluded in 2000 that the importance of a portion of a species' range 
should be measured with respect to the conservation of imperiled 
species, and we looked to all of the tools of conservation science 
available to help define what portion of the range of the lynx was 
    In the case of the lynx, despite the extensive contiguous U.S. 
range, not all of the existing range contains high-quality habitat. 
Many areas within what is generally described as the historical (and 
current) range of lynx have never been capable of supporting resident 
lynx populations because the habitat is naturally marginal. As such, 
this habitat cannot be biologically ``significant'' because, even in 
its original (pre-European settlement) state, it could not support lynx 
populations or prevent the species from becoming extinct if habitat 
elsewhere (the ``significant'' portion of the habitat) were to lose its 
value as lynx habitat.
    As explained in the 2000 final listing rule, much of the area 
depicted on range maps for lynx in the contiguous United States 
contains only naturally patchy habitat because that area is the 
southern edge of the boreal forest, where the boreal forest is 
transitional with other forest types. Because of the naturally patchy 
condition of southern boreal forests, snowshoe hares (the primary prey 
of lynx) are unable to achieve densities similar to those in Canada and 
Alaska, where the northern boreal forest is expansive and continuous, 
enabling snowshoe hares to reach extremely high densities (65 FR 16053, 
16077, 16081). Lower snowshoe hare densities in the contiguous United 
States in turn naturally limit the lynx populations. The quality and 
size of habitat patches affect the ability of areas to support lynx.
    The persistence of a species may depend on whether the reproductive 
success of individuals in good habitats, or sources, exceeds that of 
individuals in marginal habitats, or sinks. In sink habitats, local 
recruitment into the population (through reproduction or immigration) 
is lower than mortality. Patches of higher quality and larger size are 
more likely to act as ``sources'' of lynx or support resident lynx 
populations, whereas smaller patches and/or patches where habitat 
quality is marginal likely act as ``sinks'' because such areas are less 
likely to be able to support lynx populations (McKelvey et al. 1999a; 
65 FR 16052, March 24, 2000).
    We must clarify here that, just because habitat is marginal, does 
not mean that lynx can no longer live there, as may be the impression 
of the Court. Instead, marginal habitat means that such areas cannot 
and may never have supported resident lynx populations. They may 
support breeding pairs over a short term, or the regular presence of 
nonbreeding individuals, migrating into or passing in and out of such 
areas from source (``significant'') habitats. These areas also may be 
natural ``sinks,'' where lynx mortality is greater than recruitment and 
lynx are lost from the overall population.
    Furthermore, the habitat is marginal because it is at the southern 
edge of the boreal forest, where the boreal forest is naturally in 
transition with other forest types. Therefore, the Service did not view 
the overall size of an area mapped as lynx habitat to be directly 
relevant to the analysis of ``significance'' without consideration of 
the quality of the habitat. Marginal habitat for lynx, no matter how 
large, is not a significant portion of the range of the lynx because it 
cannot, and has never been able to, support resident lynx populations 
for any length of time.
    The 2000 final rule described what habitat values existed in the 
Northeast, Great Lakes, and Southern Rockies regions. Specifically, we 
carefully explained that:

    Northeast Region--Most lynx occurrence records in the Northeast 
were found within the ``Mixed Forest--Coniferous Forest--Tundra'' 
cover type (McKelvey et al. 1999b). This habitat type occurs along 
the northern Appalachian Mountain range from southeastern Quebec, 
western New Brunswick, and western Maine, south through northern New 
Hampshire. This habitat type becomes naturally more fragmented and 
begins to diminish to the south and west. Most of the historical 
lynx records from this region were from Maine and northern New 
Hampshire, which are directly connected with lynx populations in 
Quebec and New Brunswick, Canada.

    To further clarify this, we note that in Vermont, only four 
verified records of historic lynx occurrence exist (McKelvey et al. 
1999b). In fact, we have no evidence of a breeding population ever 
occurring in Vermont.
    Great Lakes Region--The majority of lynx occurrence records in the 
Great Lakes Region are associated with the ``mixed deciduous-coniferous 
forest'' type (McKelvey et al. 1999b) found primarily in northeastern 
Minnesota, northern Wisconsin, and the western portion of Michigan's 
upper peninsula. Most of the historical lynx records in this region are 
from northeastern Minnesota, which supported higher

[[Page 1189]]

habitat quality in addition to being directly connected with lynx 
populations in adjacent Ontario, Canada. In our 2000 final listing 
rule, we found that, although the mixed deciduous-coniferous forest 
covers an extensive area of the Great Lakes Region, we considered much 
of this area to be marginal habitat for lynx because it is a 
transitional forest type at the edge of the snowshoe hare range. 
Habitat at the edge of snowshoe hare range supports lower hare 
densities (Buehler and Keith 1982) that may not be sufficient to 
support lynx reproduction (65 FR 16056).
    Southern Rockies Region--Colorado represents the extreme southern 
edge of the range of the lynx. The southern boreal forest of Colorado 
and southeastern Wyoming is isolated from southern boreal forest in 
Utah and northwestern Wyoming by the Green River Valley and the Wyoming 
basin (Findley and Anderson 1956 in McKelvey et al. 1999b). These 
habitats likely act as a barrier that reduces or precludes 
opportunities for immigration and emigration from the Northern Rocky 
Mountains/Cascades Region and Canada. A majority of the lynx occurrence 
records in Colorado and southeastern Wyoming are associated with the 
``Rocky Mountain Conifer Forest'' type. The occurrences in the Southern 
Rockies were generally at higher elevations (1,250 to over 3,750 meters 
(m) [4,100-12,300 feet (ft)] than were all other occurrences in the 
West (McKelvey et al. 1999b). The montane and subalpine forest 
ecosystems in Colorado are naturally highly fragmented (Thompson 1994), 
as they occur at higher elevations at this latitude, which we believed 
limited the size of lynx populations in this area (65 FR 16059; March 
24, 2000).
    Further, Colorado has never supported many lynx. A total of 78 lynx 
reports rated as positive (22) or probable (56) exist in State records 
since the late 1800s (J. Mumma, Colorado Division of Wildlife, 1998); 
although McKelvey et al. (1999b) considered only 17 of these records 
    Northern Rockies/Cascades region--In this region, the majority of 
lynx occurrences were associated at a broad scale with the ``Rocky 
Mountain Conifer Forest.'' Most of the lynx occurrences are in the 
1,500-2,000 m (4,920-6,560 ft) elevation class (McKelvey et al. 1999b). 
These habitats are found in the Rocky Mountains of Montana, Idaho, 
eastern Washington, and Utah, and in the Cascade Mountains in 
Washington and Oregon. The majority of historical verified lynx 
occurrences in the contiguous United States and, at the time of the 
2000 final listing rule, the confirmed presence of resident populations 
were from this region. Washington, Montana, and Idaho are contiguous 
with lynx habitat in adjacent British Columbia and Alberta, Canada. 
Within this region, Washington, Montana, and the Greater Yellowstone 
area have a long historical record of resident lynx populations. In the 
final listing rule, the Service stated that ``the Northern Rockies/
Cascades region supports the most viable resident lynx populations in 
the contiguous United States'' (65 FR 16059; March 24, 2000).
    Therefore, we assessed each of the above areas, and concluded that 
the Northern Rockies/Cascades Region was the primary region necessary 
to support the long-term existence of the contiguous U.S. DPS. Because 
the amount of good-quality lynx habitat in the Northeast, Great Lakes, 
and Southern Rockies regions was limited, the Service did not consider 
these areas individually or collectively to be a biologically 
significant portion of the species' range. We concluded that the 
overwhelming majority of lynx found in these areas were, and 
historically had been, those that migrated into the area from source 
populations in Canada and the Northern Rockies/Cascades, respectively, 
and eventually died out, to be replaced by new migrants.
    The fact that we did not use area estimates for the Northeast or 
Great Lakes in our final rule demonstrates that we did not focus 
primarily on the size of any area in our analysis. Furthermore, the 
only area estimates we used in the final rule were for the Southern 
Rockies, Northern Rockies, and Cascades; these area estimates were used 
only in ``Factor A'' to analyze Federal land management allocations in 
lynx forest types in these areas. These estimates were not used to 
determine whether any of the areas constituted a significant portion of 
the range of the lynx. As a result, it is important to note at this 
juncture that any contention that the Great Lakes, Southern Rockies, 
and Northeast consist of three-quarters of the species' range has no 
basis because the habitat in these Regions will not now, and 
historically did not, support a population of lynx sufficient to 
maintain the species if lynx habitat in Canada, Alaska and the Northern 
Rockies/Cascades were lost.
    In summary, the Service's determination that ``[c]ollectively the 
Northeast, Great Lakes, and Southern Rockies do not constitute a 
significant portion of the [lynx] DPS'' was based on an assessment of 
the biological context of the habitat conditions and lynx status within 
its contiguous U.S. range. The 2000 final listing rule found that 
habitat for lynx in the contiguous United States is of varying quality, 
and much of it was naturally incapable of supporting adequate densities 
of snowshoe hare sufficient to sustain resident lynx populations. 
Quality of habitat is an important factor in determining 
``significance'' because marginal habitat, no matter how large, cannot 
support stable or expanding populations of lynx, except by migration of 
individual lynx from high quality (``significant'') habitat; and, in 
fact, may serve as a population sink where lynx mortality is greater 
than recruitment and lynx are lost from the overall population.

References Cited

    A complete list of all references cited herein is available upon 
request from the Montana Field Office (see ADDRESSES).


    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: December 27, 2006.
Kenneth Stansell,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. E6-22633 Filed 1-9-07; 8:45 am]