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CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AF03

NOTICE: Part III

DOCUMENT ACTION: Clarification of findings.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Notice of Remanded Determination of Status for the Contiguous United States Distinct Population Segment of the Canada Lynx

DOCUMENT SUMMARY: The Fish and Wildlife Service (Service), in response to the December 26, 2002, memorandum opinion and order of the United States District Court for the District of Columbia, in the case of Defenders of Wildlife v. Norton (Civil Action No. 002996 (GK)) and pursuant to the Endangered Species Act of 1973, as amended (ESA or Act), provides a clarification to the findings we made in support of the final rule that listed Canada lynx (Lynx canadensis) (lynx) as threatened. The lynx is currently listed as threatened in the contiguous United States as a Distinct Population Segment (DPS) that includes the States of Colorado, Idaho, Maine, Michigan, Minnesota, Montana, New Hampshire, New York, Oregon, Utah, Vermont, Washington, Wisconsin, and Wyoming. As a result of our reanalysis of the basis for that final rule, which was directed by the Court, we find that the lynx is not endangered throughout a significant portion of its range. This finding does not affect the status of the lynx as currently set forth in 50 CFR 17.11; the lynx continues to be listed as threatened in the States listed above. This finding also does not affect the special rule pursuant to section 4(d) of the Act for the Canada lynx set forth in 50 CFR 17.40(k).

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL 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. Norton (Civil Action No. 002996 (GK)) initiated action in Federal District Court, challenging the listing of the lynx as threatened and alleging violations of the Act and the Administrative Procedure Act (5 U.S.C. 551 et seq.). Plaintiffs argued that the Service acted arbitrarily and capriciously when it (1) did not treat the four lynx regions as separate DPSs, (2) determined that the lack of guidance for conservation of lynx in National Forest Land and Resource Management Plans and Bureau of Land Management (BLM) Resource Area Management Plans is the single factor threatening the contiguous United States DPS of lynx, (3) did not designate critical habitat for the lynx, and (4) determined that ``[c]ollectively, the Northeast, Great Lakes and Southern Rockies do not constitute a significant portion of the range of the DPS.''

On December 26, 2002, the Court issued its memorandum opinion and order, deciding that the Service's determination that ``[c]ollectively, the Northeast, Great Lakes and Southern Rockies do not constitute a significant portion of the range of the DPS'' must be set aside and remanded to the Service for further consideration of the lynx's status under the ESA consistent with the Court's memorandum opinion. The Court explained that the Service's determination about the four regions was counterintuitive and contrary to the plain meaning of the ESA phrase ``significant portion of its range.'' The Court did not address the issues concerning the threats and the DPSs. The Court also ordered the Service to ``undertake prompt rulemaking'' in order to designate critical habitat for lynx, and ordered injunctive relief directed at section 7 consultation.

The Court ordered the determination concerning a ``significant portion of its range'' be remanded to the Service and completed within 180 days of the date of the order consistent with the Court's memorandum opinion. With this document, the Service is providing its consideration of this issue. This document does not address critical habitat for the lynx, since our listing budget is currently insufficient to begin work on a rule for critical habitat. The Service will seek public comment in the future when it proposes critical habitat. This document also does not address the special rule for Canada lynx established in the March 24, 2000, final listing rule. That rule, which is found in 50 CFR 17.40(k), remains in effect.

As noted above, plaintiffs contend that our determination that ``[c]ollectively, the Northeast, Great Lakes, and Southern Rockies do not constitute a significant portion of the range of the DPS,'' was critical to our decision not to list the lynx as endangered. Plaintiffs maintain that, if those three regions are considered collectively to be a significant portion of the DPS, ``then the Lynx's highly imperilled status in those three areas would necessitate listing of the entire DPS as endangered.'' Pls. Mot. for Summ. J. at 30 (emphasis in original). However, the Service would need to find that the lynx is endangered in these areas and that they were significant in order to list the entire DPS. Therefore, we first reviewed all of the threats to the lynx in these areas to determine whether it is in danger of extinction in each area. We identified two areas or parts of areas in which the lynx might be in danger of extinction. We then determined whether either of those areas (or parts of areas) constitutes a significant portion of the range of the lynx.

The remainder of this section describes some important concepts used throughout the following analysis. Later sections include background information on the natural history and range of the lynx, responses to public comments, an analysis of the quantity and quality of habitat throughout the range of the DPS, an analysis of the threats facing the species in the areas addressed by the remand, a finding as to the areas in which the lynx currently are in danger of extirpation, and a finding that those areas do not constitute a significant portion of the range of the lynx.

As a preliminary matter, we note that the Court suggested, but did not decide, that ``significant'' is appropriately defined in this context as ``a noticeably or measurably large amount,'' citing a dictionary definition. However, there are other definitions of significance that pertain to importance. Moreover, we believe this is more consistent with the intent of the Act in the context of the provision at issue. Otherwise, a severe threat to a small area within the range of a species would always require the species to be listed as endangered, no matter how inconsequential that area might be given the biology of the species. For example, building a large dam may make the area covered by the resulting artificial lake unsuitable for an aquatic species currently resident in the river to be dammed. The area covered by the lake would be a ``measurably large'' area, and therefore a measurably large portion of the range of the species.
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However, if the species is sufficiently widespread and healthy, the area subject to the threat would not be biologically important, and we believe it was not the intent of Congress that all such circumstances lead to the listing of all affected species.

Understanding ``significant'' to mean ``important,'' the following analysis concentrates on applying our understanding of the ecology of the lynx to the geography of its habitat. This allows us to determine whether a given area is a significant portion of the range of lynx.

With the help of new information available as a result of ongoing research, we continue to improve our understanding of lynx ecology in the contiguous United States. In delineating the range of the lynx in the contiguous United States, we must take into account lynx life history requirements, population dynamics, and the natural features of the vegetation communities that make up lynx habitat. The following list summarizes fundamental elements that determine the range of the lynx in the contiguous United States. We describe these elements in further detail later in this notice.
(1) Lynx in the contiguous United States are at the southern margins of a widelydistributed lynx population whose center is in northcentral Canada and Alaska. Lynx populations in the contiguous United States are sustained by cyclic influx from lynx populations in Canada.
(2) Lynx are specialized predators of snowshoe hare (Lepus americanus). Lynx populations track hare cycles. Abundant hares are necessary to support survival of lynx kittens and recruitment into and maintenance of the lynx population. As a result, depending on habitat quality, local lynx populations naturally may not be able to survive through a cyclic low in the hare cycle.
(3) Lynx and snowshoe hare habitat is boreal forest where there are cold winters with deep snow.
(4) In the contiguous United States, the boreal forest is at its southernmost extent, transitions into other vegetation communities, and is naturally patchy. These natural patches may not be big enough or of high enough quality to support a resident lynx population.
(5) The habitat within these patches changes over time and location, naturally becoming suitable or unsuitable for lynx with forest succession or changes in local climate conditions.
(6) Lynx disperse long distances when hare populations decline. As a result, they can colonize suitable but unoccupied habitats, augment existing resident populations, or disperse to habitats where they cannot survive.

As a result of the factors described above, the range of the lynx in the contiguous United States is comprised of areas supporting resident, breeding populations and areas supporting occasional dispersers:
(1) Resident populationResident, breeding populations exist in areas of abundant, higherquality habitat. These areas are ``core'' areas essential to maintaining lynx in the contiguous United States. During cyclic population lows, resident lynx populations are naturally reduced to extremely low numbers of individuals. Throughout this document, we use the term ``resident population'' to refer to a group of lynx that has exhibited longterm persistence in an area as determined by a variety of factors, such as evidence of reproduction, successful recruitment into the breeding cohort, and maintenance of home ranges.
(2) DispersersLynx records in many parts of the contiguous United States are of dispersing animals. Lynx occur as dispersers where boreal forest is isolated, patchy, or of marginal quality such that it cannot sustain a resident, breeding lynx population. We include areas of the contiguous United States that contain boreal forest as potential lynx range. Although dispersing lynx may periodically occupy some of this range, there is a low probability that habitat quality and quantity are sufficient to support a breeding population. It is possible that some of the large outlying patches of boreal forest may periodically support some breeding lynx; however, evidence of this is minimal and our best information indicates that these areas are likely to contribute little to the persistence of the species in the contiguous United States.

Some dispersing lynx are found in completely unsuitable habitats, such as prairie or deciduous forest, where they are unable to survive in the long term. We do not include such areas within the range of lynx because such occurrences are unpredictable and because, to the best of our knowledge, such areas have not contained conditions capable of supporting lynx since at least the time of European settlement.

We use the word ``dispersers'' to refer to lynx that have left the area they originally occupied for various reasons, most often when snowshoe hare populations decline. To successfully disperse, lynx must find suitable habitat and a mate and must successfully reproduce (McKelvey et al. 2000a). Successful dispersals can result in the colonization of unoccupied habitats and contribute to the persistence of the metapopulation (as described in the next paragraph). Unsuccessful dispersal is a natural phenomenon that occurs when lynx move to habitats that are unable to sustain lynx. These individuals are unable to survive and are lost from the metapopulation. Unsuccessful dispersal is demonstrated by records of lynx in areas such as North Dakota, Nebraska, and Iowa, which cannot support lynx populations in the long term (Adams 1963; Gunderson 1978; W. Jobman, U.S. Fish and Wildlife Service, in litt. 1997).

Another word we use is ``metapopulation.'' According to McKelvey et al. (2000a), a metapopulation is a number of discrete subpopulations within habitat patches, connected by dispersal. Through time, subpopulations may go extinct (no longer existing or living) and be recolonized, but the larger metapopulation persists. We believe lynx in the contiguous United States are part of a larger metapopulation with lynx populations in Canada.

The range of the lynx must be considered differently from the range of other species that are less mobile and have more stable population dynamics. Because the lynx is highly mobile and has cyclic population dynamics that are tied to its primary prey, the snowshoe hare, numbers of lynx naturally fluctuate and become extremely low at times during a cycle. Additionally, where snowshoe hare populations are not adequate, resident lynx populations cannot be sustained. Because of this, resident lynx populations never occurred everywhere boreal forest existed in the contiguous United States. Where the boreal forest was naturally more patchy and marginal the habitat was incapable of supporting an adequate snowshoe hare population that in turn was able to support a resident lynx population over time. As a result, only a few areas in the contiguous United States historically supported adequate quantity and quality of habitat to support resident lynx populations over time. Many historical lynx occurrences across a large area of the contiguous United States were likely dispersers. The occurrence of dispersing lynx is unpredictable, and dispersing lynx will continue to periodically move into areas that are not lynx habitat. This historic, natural condition continues to exist today, as will be discussed in this document.

Natural History

In the following section we describe in more detail than we did in the final rule the natural history, population
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dynamics, and habitat of lynx in the contiguous United States, information necessary to delineate lynx range. The lynx is a medium sized cat with long legs; large, wellfurred paws; long tufts on the ears; and a short, blacktipped tail (McCord and Cardoza 1982). The lynx's long legs and large feet make it highly adapted for hunting in deep snow.

Lynx are highly specialized predators of snowshoe hare. The North American distribution of the lynx is nearly the same as that of the snowshoe hare, both of which are strongly associated with boreal forest (Bittner and Rongstad 1982; McCord and Cardoza 1982; Quinn and Parker 1987; Agee 2000; Aubry et al. 2000; McKelvey et al. 2000b). Boreal forests are cold and moist with conifer trees, the predominant type of trees being species of spruce and fir (ElliotFisk 1988). Lynx habitat can be generally described as boreal forests that have cold winters with deep snow and that provide a snowshoe hare prey base (Quinn and Parker 1987, McKelvey et al. 2000b, Mowat et al. 2000). For example, in the Northeast, lynx were most likely to occur in areas with greater than 268 centimeters (cm) (105 inches (in)) of annual snowfall (Hoving 2001). Boreal forests are naturally dynamic and, therefore, are known as ``disturbance forests'' (ElliotFisk 1988, Agee 2000). The landscape changes over time and location as the forest undergoes natural succession following natural or humancaused disturbances such as fire, insect epidemics, wind, ice, disease, and logging. Largescale disturbance is necessary to create the mosaic of different successional forest stages that provide suitable foraging and denning habitat for lynx. Lynx in the contiguous United States are at the southern margins of a widely distributed lynx population that is most abundant in northern Canada and Alaska.

To understand habitat relationships of lynx one must first understand the habitat relationships of snowshoe hares, their primary prey. Snowshoe hares use spruce and fir forests with dense understories that provide forage, cover to escape from predators, and protection during extreme weather (Wolfe et al. 1982; Monthey 1986; Hodges 2000a, 2000b). Generally, earlier successional (younger) forest stages have greater understory structure than do mature forests and, therefore, support higher hare densities (Fuller 1999, Hodges 2000a, 2000b). Lynx generally concentrate their hunting activities in areas where hare populations are high (Koehler et al. 1979; Parker 1981; Ward and Krebs 1985; Major 1989; Murray et al. 1994; O'Donoghue et al. 1997, 1998a). In Maine, snowshoe hare abundance and lynx occurrence are positively associated with late regeneration forests (forest stands that are growing back 12 to 30 years after being clearcut and have greater than 50 percent canopy closure), evidence that lynx are selecting habitat primarily on the abundance of primary prey (Hoving 2001).

Lynx numbers and snowshoe hare densities in the contiguous United States generally do not get as high as in the center of their range in Canada, and there is no evidence they ever did so in the past (Hodges 2000a, 2000b; McKelvey et al. 2000b). It appears that northern and southern hare populations have similar cyclic dynamics but that in southern areas both peak and low densities are lower than in the north (Hodges 2000b). However, it is unclear whether hare populations cycle everywhere in the contiguous United States. Relatively low snowshoe hare densities at southern latitudes are likely a result of the naturally patchy, transitional boreal habitat at southern latitudes that prevents hare populations from achieving densities similar to those of the expansive northern boreal forest (Wolff 1980; Buehler and Keith 1982; Koehler 1990; Koehler and Aubry 1994). Additionally, the presence of more predators and competitors of hares at southern latitudes may inhibit the potential for highdensity hare populations with extreme cyclic fluctuations (Wolff 1980). As a result of naturally lower snowshoe hare densities, lynx densities at the southern part of the range rarely achieve the high densities that occur in the northern boreal forest (Aubry et al. 2000).

The association between lynx and snowshoe hare is considered a classic predatorprey relationship (Saunders 1963; van Zyll de Jong 1966; Quinn and Parker 1987, Krebs et al. 2001). In northern Canada and Alaska, lynx populations fluctuate on approximately 10year cycles that follow the cycles of hare populations (Elton and Nicholson 1942; Hodges 2000a, 2000b; McKelvey et al. 2000b). Generally, researchers believe that when hare populations are at their cyclic high, the interaction of predation and food supply causes hare populations to decline drastically (Buehler and Keith 1982; Krebs et al. 1995; O'Donoghue et al. 1997, Krebs et al. 2001). There is little evidence of regular snowshoe hare cycles in the Northeast and southern Quebec (Hoving 2001), but hare populations do fluctuate widely in this region. Hare fluctuations in this region may be more influenced by forest practices, weather, and other ecological factors. Snowshoe hare provide the quality prey necessary to support highdensity lynx populations (Brand and Keith 1979). Lynx also prey opportunistically on other small mammals and birds, particularly when hare populations decline (Nellis et al. 1972; Brand et al. 1976; McCord and Cardoza 1982; O'Donoghue et al. 1997, 1998a). Red squirrels (Tamiasciurus hudsonicus) are an important alternate prey (O'Donoghue et al. 1997; 1998a; Apps 2000; Aubry et al. 2000). However, a shift to alternate food sources may not sufficiently compensate for the decrease in hares consumed to be adequate for lynx reproduction and kitten survival (Brand and Keith 1979, Koehler 1990, Koehler and Aubry 1994). When snowshoe hare densities decline, the lower quality diet causes sudden decreases in the productivity of adult female lynx and decreased survival of kittens, if any are born during this time; as a result, recruitment of young into the population nearly ceases during cyclic lows of snowshoe hare populations (Nellis et al. 1972; Brand et al. 1976; Brand and Keith 1979; Poole 1994; Slough and Mowat 1996; O'Donoghue et al. 1997, Mowat et al. 2000).

Lynx den sites are found where coarse woody debris, such as downed logs and windfalls, provides denning sites with security and thermal cover for lynx kittens (McCord and Cardoza 1982; Koehler 1990; Koehler and Brittell 1990; Slough 1999; Squires and Laurion 2000; J. Organ, U.S. Fish and Wildlife Service, in litt. 1999). The integral component for all lynx den sites appears to be the amount of downed, woody debris present, not the age of the forest stand (Mowat et al. 2000). In Maine, 17 den sites have been located in a variety of stand types, including 10 to 20yearold clearcut and adjacent residual stands (J. Organ, U.S. Fish and Wildlife Service, in litt. 1999; G. Matula, Maine Department Inland Fisheries and Wildlife in litt. 2003). Maine den sites are characterized by regenerating hardwoods and softwoods, dense understory, and abundant coarse woody debris (J. Organ, in litt. 1999, 2003). In Washington, lynx denned in lodgepole pine (Pinus contorta), spruce (Picea spp.), and subalpine fir (Abies lasiocarpa) forests older than 200 years with an abundance of downed woody debris (Koehler 1990). A den site in Wyoming was located in a mature subalpine fir/lodgepole pine forest with abundant downed logs and dense understory (Squires and Laurion 2000).

Lynx require very large areas containing boreal forest habitat. In the Northeast, lynx were most likely to occur in areas containing suitable
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habitat that were greater than 100 square kilometers (km \2\) (40 square miles (mi \2\)) (Hoving 2001). The requirement for large areas also is demonstrated by home ranges that encompass many square miles. The size of lynx home ranges varies by the animal's gender and age, abundance of prey, season, and the density of lynx populations (Hatler 1988; Koehler 1990; Poole 1994; Slough and Mowat 1996; Aubry et al. 2000; Mowat et al. 2000). Based on a limited number of studies in southern boreal forest, the average home range for males is 151 km \2\ (58 mi \2\), for females it is 72 km \2\ (28 mi \2\) (Aubry et al. 2000). Recent home range estimates from Maine are 70 km \2\ (27 mi \2\) for males and 52 km \2\ (20 mi \2\) for females (G. Matula, in litt. 2003). However, documented home ranges in both the southern and northern boreal forest vary widely from 8 to 800 km \2\ (3 to 300 mi \2\) (Saunders 1963; Brand et al. 1976; Mech 1980; Parker et al. 1983; Koehler and Aubry 1994; Apps 2000; Mowat et al. 2000; Squires and Laurion 2000; Squires et al. 2001; G. Matula, in litt. 2003). Generally, it is believed that larger home ranges, such as have been documented in some areas in the southern extent of the species' range in the West, are a response to lowerdensity snowshoe hare populations (Koehler and Aubry 1994; Apps 2000; Squires and Laurion 2000).

Lynx are highly mobile and have a propensity to disperse. Long distance movements (greater than 100 kilometers (km) (60 miles (mi))) are characteristic (Mowat et al. 2000). Lynx disperse primarily when snowshoe hare populations decline (Ward and Krebs 1985; Koehler and Aubry 1994; O'Donoghue et al. 1997; Poole 1997). Subadult lynx also disperse even when prey is abundant (Poole 1997), presumably as an innate response to establish home ranges. Lynx also make exploratory movements outside their home ranges (Squires et al. 2001). Lynx are capable of moving extremely long distances (greater than 500 km (300 mi)) (Mech 1977; Brainerd 1985; Washington Department of Wildlife 1993; Poole 1997; Mowat et al. 2000; Squires et al. 2001); for example, a male was documented traveling 620 km (380 mi) (Brainerd 1985). A male lynx in Wyoming made an exploratory movement of 730 km (450 mi) round trip from its home range (Squires et al. 2001). While it is assumed lynx would prefer to travel where there is forested cover, the literature contains many examples of lynx crossing large, unforested openings (Roe et al. 2000). The ability of both male and female lynx to disperse long distances, crossing unsuitable habitats, indicates they are capable of colonizing suitable habitats and finding potential mates in areas that are isolated from source lynx populations.

Range of Lynx in the Contiguous United States

Within the contiguous United States, the lynx's range coincides with that of the southern margins of the boreal forest along the Appalachian Mountains in the Northeast, the western Great Lakes and the Rocky Mountains and Cascade Mountains in the West. In these areas, the boreal forest is at its southern limits, becoming naturally fragmented into patches of varying size as it transitions into subalpine forest in the West and deciduous temperate forest in the east (Agee 2000, Wisconsin Department Natural Resources, in litt. 2003). Because the boreal forest transitions into other forest types to the south, scientists have difficulty mapping its exact boundaries (ElliotFisk 1988). Therefore, precisely identifying and describing the distribution of lynx habitat also is difficult because there are several vegetation and landform classifications and descriptions that have been published for various parts of North America (U.S. Forest Service and Bureau of Land Management 1999). However, the term ``boreal forest'' broadly encompasses most of the vegetative descriptions of this transitional forest type that makes up lynx habitat in the contiguous U.S. (Agee 2000).

In addition to appropriate vegetation type, delineation of the range of the lynx within the contiguous United States must consider snow conditions. Lynx are at a competitive advantage over other carnivores (e.g., bobcats (Lynx rufus) or coyotes (Canis latrans)) in areas that have cold winters with deep snow because of the lynx's morphological adaptations for hunting and surviving in such environments. Therefore, lynx populations may not be able to successfully compete and persist in areas with insufficient snow even if suitable forest conditions otherwise appear to be present (Ruediger et al. 2000; Ruggiero et al. 2000b; Hoving 2001; S. Hassett, Wisconsin Department Natural Resources, in litt. 2003). A consistent winter presence of bobcats indicates such areas are not of high quality for lynx.

Lynx in the contiguous United States are part of a larger metapopulation whose center is located in the northern boreal forest of central Canada; lynx populations emanate from this area (Buskirk et al. 2000b; McKelvey 2000a, 2000b). It appears hare populations and, as a result, lynx populations in the southern part of the range are cyclic, although the amplitude of the fluctuations in this portion of the range is not as extreme as in the center of the range (Aubry et al. 2000; Hodges 2000a, 2000b; Malloy 2000; McKelvey 2000b). When there is a high in the lynx population in central Canada, it acts like a wave radiating out to the margins of the lynx range (McKelvey et al. 2000a, 2000b). We know from historic data that the magnitude of the lynx population high emanating from the central Canadian boreal forest varies for each cycle (McKelvey et al. 2000a, 2000b). This wave can be produced by local populations reacting to environmental conditions, dispersers, or a combination of these (McKelvey et al. 2000b). Schwartz et al. (2002) concluded this wave is driven by dispersers, based on findings of a high level of gene flow between lynx in Alaska, Canada, and the western United States.

Lynx populations in the northeastern United States and southeastern Canada are separated from those in northcentral Canada by the St. Lawrence River. There is little evidence of regular hare or lynx population cycles in this area (Hoving 2001), but wide fluctuations in lynx and snowshoe hare populations do occur. On a smaller scale, fluctuating populations in the core of this area (Quebec's Gaspe Peninsula, western New Brunswick, and northern Maine) can potentially influence lynx distribution up to several hundred miles distant.

We believe lynx dispersing during periods of population highs will occupy many patches of boreal habitat at the periphery of their range. Some patches will be suitable to maintain a longterm population and some will not. Where the boreal forest habitat patches within the contiguous United States are large, with suitable habitat, prey, and snow conditions, resident populations of lynx are able to survive throughout the low period of the approximately 10year cycle. Most likely the influx of lynx from populations in Canada at the high point of the cycle augments these resident populations. It is likely that some of these habitat patches within the contiguous United States are able to act as sources of lynx (where recruitment is greater than mortality) that are able to disperse and potentially colonize other patches (McKelvey et al. 2000a).

In other areas, the lynx that remain in an area after a cyclic population high may be so few or in naturally marginal habitat that they are not able to persist or establish local populations, although some reproduction may occur. Such
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areas naturally act as ``sinks,'' where lynx mortality is greater than recruitment and lynx are lost from the overall population (McKelvey et al. 2000a). Sink habitats are most likely those places on the periphery of the southern boreal forest where habitat naturally becomes more patchy and more distant from larger lynx populations. We consider lynx found in these sink habitats to be dispersers but we include these areas within the range of the lynx. Changes in the habitat conditions or cyclic fluctuations in the prey populations may cause some habitat patches to change from being sinks to sources and vice versa. Through this natural process, local lynx populations in the contiguous United States may ``blink'' in and out as the metapopulation goes through the 10year cycle. We conclude that where habitat is of high enough quality and quantity, resident lynx populations are able to become established or existing populations are augmented, aiding in their longterm persistence.

We include areas that contain boreal forest but that support only dispersers within the range of the lynx because of the possibility lynx could establish a small, local population and contribute to the persistence of the metapopulation. However, evidence of this is minimal.

An example of the cyclic population ``wave'' occurred in the 1960s and 1970s, when numerous lynx were reported in the contiguous United States far from source lynx populations. These records of dispersing lynx correlate to unprecedented cyclic lynx highs in Canada (Adams 1963; Harger 1965; Mech 1973; Gunderson 1978; Thiel 1987; McKelvey et al. 2000b; Mowat et al. 2000). These dispersers frequently were documented in areas such as Wisconsin, that are close to source populations of lynx in Canada or possibly northeastern Minnesota and that contain some boreal forest. But there also have been a number of occurrences of dispersers in unsuitable habitats far from source populations, such as North Dakota prairie (Adams 1963; Gunderson 1978; Thiel 1987; McKelvey et al. 2000b; Verts and Carraway 2001).

Rather than recognizing that the cyclic peaks of the early 1960s and 1970s were anomalous highs for the 20th century, as explained in the final rule, some wildlife managers expected subsequent cycles to be equally high. Managers became concerned when harvest returns in the 1980s and 1990s indicated comparatively low cycles. However, as thoroughly described in the final rule, lynx harvest returns in the 1980s and early 1990s were not unusual nor appreciably lower than those recorded prior to the 1960s.

Some maps (e.g., Hall and Kelson 1959, Tanimoto and Garton 1993) incorrectly portray the range of the lynx by encompassing peripheral records from areas that are not within boreal forest or do not have cold winters with deep snow, such as prairie or deciduous forest. Such maps have led to a misperception that the historic range of the lynx in the contiguous United States was once much more extensive than ecologically possible. Records of lynx outside of southern boreal forest in peripheral habitats that are unable to support lynx represent longdistance dispersers that are lost from the metapopulation unless they return to boreal forest and contribute to the persistence of a population. These unpredictable and temporary occurrences are not included within either the historic or current range of lynx because they are well outside of lynx habitat. This includes records from Connecticut, Indiana, Iowa, Massachusetts, Nebraska, Nevada, North Dakota, Ohio, Pennsylvania, South Dakota, and Virginia (Hall and Kelson 1959; Burt 1954 in Brocke 1982; Gunderson 1978; McKelvey et al. 2000b; J. Belfonti, The Nature Conservancy, in litt. 1994; S. Johnson, Indiana Department of Natural Resources, in litt. 1994; P. Jones, Ohio Department of Natural Resources, in litt. 1994; South Dakota Natural Heritage Program, in litt. 1994; W. Jobman, U.S. Fish and Wildlife Service, in litt. 1997; Smithsonian Institute, in litt. 1998). In the proposed rule to list the lynx, we included Massachusetts and Pennsylvania in the historic range of the lynx but removed those areas from the range in the final rule because of better information that historically habitat in these States was not capable of supporting lynx. We consider both the historic and current range to consist of Colorado, Idaho, Maine, Michigan, Minnesota, Montana, New Hampshire, New York, Oregon, Utah, Vermont, Washington, Wisconsin, and Wyoming because these States support some boreal forest and have more frequent records of lynx.

Previous Federal Action

The final rule that listed lynx as threatened in the contiguous United States described the history of the Service's actions concerning the listing of the lynx. That discussion is incorporated herein by reference. Since publication of the final rule and as a result of the litigation that requires us to reconsider our determination about the significant portion of the range of lynx, we reopened the comment period for 30 days to acquire information to assist us during our reconsideration (March 17, 2003, 68 FR 12611). This comment period closed on April 16, 2003.

Summary of Comments and Recommendations

As a result of the reopened comment period in March and April 2003, the Service received 118 comments and recommendations. Of these comments, 2 were from Congressional or Legislative officials, 6 were from Federal agencies; 6 from States; 2 from County Commissioners, 17 from environmental organizations, 3 from businesses, 9 from Industry Trade Associations, 1 from a University, and 70 from individuals. Some commenters provided information relevant to our determination regarding the significant portion of the range of lynx. Comments of a similar nature are grouped into general issues. These issues and our responses are discussed below.

We received numerous comments covering a broad spectrum of lynx related issues that are not the subject of this notice or are beyond the scope of the court's remand. We are not addressing these comments in this document. These comments covered such subjects as: designation of critical habitat for lynx; the existence of various DPSs of lynx; general support for or opposition to protection of lynx under the Act; support for or opposition to lynx reintroduction efforts; classifying the lynx reintroduction in the Southern Rocky Mountains as an experimental, nonessential population; concern that the Service was prioritizing the listing and protection of charismatic megafauna ahead of other flora and fauna; the competency and intent of the Service; an internet retail vendor of lynx pelts; recovery planning; and streamlining section 7 consultations. In particular, we received a number of comments as to the status of the lynx throughout the U.S. DPS (i.e., endangered, threatened, or neither). However, the only portion of our March 24, 2000 final listing determination that the court remanded for further consideration was our determination that ``[c]ollectively, the Northeast, Great Lakes and Southern Rockies do not constitute a significant portion of the range of the DPS.'' Our finding on this limited remand is discussed below. To the extent that the information we received since the final listing determination, or that we receive in the future, causes us to reevaluate the listing of the lynx, we will issue an appropriate proposed rule when resources allow.

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We conducted peer review of the proposed rule to list the contiguous United States population of lynx during the open public comment period in 1998. For this courtordered reanalysis of the 2000 final rule listing the lynx, we did not have time to conduct additional peer review.

Issue 1: Technical information was provided based on recent research on lynx and snowshoe hares in Maine and Montana. Additional technical information on lynx populations and lynx habitat quality and quantity was provided by the State of Maine, the State of Vermont, the State of Colorado, the State of Wisconsin, the State of Wyoming, the State of Minnesota, research by the University of Maine and the University of Montana, the U.S. Forest Service, the BLM, the National Park Service, a number of environmental and industry groups, and individuals.

Response: We incorporated this information into this document.

Issue 2: Several commenters expressed support or concern for the Service's determination considering the significant portion of the range of the lynx. Specifically, commenters explained their concerns about whether or not the Northeast, Great Lakes, or the Southern Rockies constitute a significant portion of the range of the lynx.

Response: The Act defines ``endangered species'' as any species which is in danger of extinction throughout all or a significant portion of its range. A ``threatened species'' is any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The District Court found our determination that the Northeast, Great Lakes, and the Southern Rockies do not constitute a significant portion of the range of the lynx was arbitrary and capricious, and as a result of that finding, directed us to reevaluate it. Based on our reanalysis, we have determined that lynx is not in danger of extinction throughout a significant portion of its range in the contiguous United States DPS.

Issue 3: Several commenters opposed combining the Cascades in general, or specific locations within Washington, with the Northern Rocky Mountain region for our analysis.

Response: We combine the Cascades with the Northern Rocky Mountain region for our analysis and for convenience only because the issues in both regions are similar and frequently the best information available addressed both regions. The two areas are separated by the Okanogan River valley in northern Washington, which lynx can cross, although we believe most movement of lynx to be northsouth within contiguous habitat with Canada and less likely that lynx would move between habitat patches within Washington. Furthermore, the Cascades alone supports the smallest amount of lynx habitat of any region within the contiguous United States. The relative size and close proximity of the lynx habitat in the Cascades to that in the Northern Rocky Mountains further supports considering both areas as one. Combining these two regions has not in any way diminished or obscured our analysis of the status of lynx or the threats to the species.

Issue 4: Several commenters suggested the Cascades, the Cascades/ Northern Rocky Mountains, the Southern Rockies, the Great Lakes, and the Northeast Lynx populations should each be designated as individual DPSs. Other commenters believed the contiguous United States as a whole does not fulfill the criteria to be a DPS for lynx.

Response: Reevaluation of DPS issues is outside of the scope of the remand in this case. However, because the plaintiffs' claims regarding application of the Service's authority to list DPSs have not yet been addressed by the court, we are responding to these comments to update and elaborate on our analysis in the final rule. The Act gives us the authority to list fish, wildlife and plants by species, subspecies, or by DPS of any species of vertebrate fish or wildlife which interbreeds when mature. However, Congress directed that we use our authority to list by DPS sparingly (see Senate Report 151, 96th Congress, 1st Session). The Service and National Marine Fisheries Service DPS policy (61 FR 4721) identifies criteria that must be met for a vertebrate group to qualify as a DPS, but it does not require that we designate a DPS in all cases where a vertebrate group meets the DPS criteria. The Service lists, reclassifies, or delists at the level we believe to be most appropriate to carry out the conservation provisions of the Act.

In this document we reaffirm our determination in the final rule to list the lynx in the contiguous United States as a single DPS. There has been no new information since the final rule was published in 2000 that compels us to change our original determination. Subsequent to issuing the proposal to list the lynx in 1998, we evaluated whether any of the four regions individually fulfilled the criteria to be listed as a DPS. As described in the final rule, we recognize that within the contiguous United States the lynx occurs in four regionsthe Northeast, Great Lakes, Southern Rocky Mountains, and Northern Rocky Mountains/Cascades. As described elsewhere in this document, we combine the Northern Rocky Mountains and Cascades in our analysis because the two regions are only separated by the Okanogan River valley, which lynx can cross, and forest types and land ownership are similar. Furthermore, the Cascades alone support the least amount of lynx habitat of any region in the contiguous United States. In evaluating whether a region qualified as a separate DPS, we analyzed whether lynx in each region were both discrete and significant, as required by our DPS policy. We concluded that within the contiguous United States these regions are geographically isolated from each other and, therefore, are discrete. Since the final rule, we are less certain that the Southern Rocky Mountains regions were historically as isolated as described by some authors. We believe it is likely that lynx in the Southern Rocky Mountains region may have been dispersers that arrived during extremely high population cycles, as indicated by the fact that the last verified record of lynx in the region is from 1973, which correlates to an extreme cyclic population high documented throughout the contiguous United States and in Canada. As a result, our original conclusion that the Southern Rocky Mountains supported an isolated resident lynx population may not be correct, and the region should perhaps be considered connected to the Northern Rocky Mountains/Cascades region.

When evaluating the status of a potential DPS, the DPS policy requires that we evaluate the significance of the population segment in relation to the taxon. A taxon is the taxonomic group of animals to which the population belongsin this case the species Lynx canadensis. The DPS policy identifies elements that may be considered in determining the discrete population segment's importance to the taxon to which it belongs. These include: (1) Persistence of the discrete population segment in an ecological setting unusual or unique for the taxon, (2) evidence that loss of the discrete population segment would result in a significant gap in the range of a taxon, (3) evidence that the discrete population segment represents the only surviving natural occurrence of a taxon, and (4) evidence that the discrete population segment differs markedly from other populations
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of the species in its genetic characteristics.

Lynx canadensis has an extensive distribution in North America, existing in the boreal forest from Alaska throughout Canada from the Yukon and Northwest Territories south across the United States border and east to the Maritime Provinces and the Island of Newfoundland. Of the entire North American range of the lynx, only a small portion extends into the contiguous United States. Individually, the Northeast, Great Lakes, Southern Rocky Mountains, and Northern Rocky Mountains/ Cascades account for an extremely small fraction of the entire range of the taxon, the loss of which would not result in a significant gap in the range of the taxon. Within all four regions of the contiguous United States the distribution of lynx is associated with the southern extensions of the boreal forest, where the predominant vegetation in each region is spruce and fir types, although the individual species of vegetation varies. As is true throughout the range of Lynx canadensis, within these boreal forests in each region within the contiguous United States, the important element for lynx is forest structure that provides food and cover for snowshoe hares. Lynx cannot sustain breeding populations without an adequate snowshoe hare population. Additionally, the forest must provide cover for lynx dens. Such habitat conditions occur in each of the four regions. As a result, we determined that none of the regions individually constitute significantly unique or unusual ecological settings. The only genetic analysis of lynx populations shows that there is a high level of gene flow between lynx populations in Alaska, western Canada and the western contiguous United States (Schwartz et al. 2002). Genetic analysis comparing lynx populations within the contiguous United States has not been done. Finally, lynx in the different regions of the contiguous United States clearly are not the only surviving natural occurrence of lynx. Therefore, the individual regions do not fulfill the significance criteria under our DPS policy and, as a result, do not constitute separate DPSs. The DPS policy allows us to use the international boundary with Canada to delineate a discrete DPS in the contiguous United States. As described in the final rule, lynx in the contiguous United States may be considered ecologically significant because lynx habitat in the contiguous United States is a transitional type of southern boreal forest rather than the classic boreal forest of northern latitudes in Canada and Alaska, which is the center of lynx range. Within this transitional boreal forest within the contiguous United States there are core areas in Maine, Minnesota, Montana, Washington and likely Idaho that support resident, breeding lynx populations, the loss of which would result in a significant gap in the range of lynx. Therefore, we once again conclude the listable entity is the contiguous United States DPS of the lynx, consisting of the Northeast, Great Lakes, Southern Rocky Mountains, and Northern Rocky Mountains/Cascades.

Issue 5: Several commenters raised concerns about threats that were beyond the control of Federal land management practices, particularly in the Northeast where much of the forested lynx habitat is primarily in private ownership.

Response: We recognize that lynx habitat occurs on nonFederal lands, particularly in the Northeast. We do not have specific information on the amount of lynx habitat on nonFederal lands nor precise information on the type of activities that occur on such lands. NonFederal landowners are under no obligation to identify lynx habitat on their lands nor do they have to supply any information to the Service regarding these lands. We solicited information about non Federal lands during the reopened comment period. To the extent possible, we attempted to better understand and assess the activities on nonFederal lands that could affect lynx. Our analysis is described in the ``Summary of Factors Affecting the Species'' section.

Issue 6: Several other comments noted the reduced threat on Federal lands, particularly National Forest lands, resulting from lynx habitat management plans.

Response: We agree that threats to lynx as a result of a lack of Federal land management plan guidance to conserve lynx, as identified in the final rule, have been somewhat alleviated. As described in ``Factor D,'' Conservation Agreements the U.S. Forest Service and BLM have with the Service, and the biological opinion on National Forest and BLM land management plans committed the U.S. Forest Service and BLM to use the Lynx Conservation Assessment and Strategy (LCAS) in determining the effects of actions on lynx. The U.S. Forest Service further committed to deferring any actions that both would adversely affect lynx and do not involve third parties until such time as the Forest Plans are amended to adequately conserve lynx. The ongoing adherence to the Conservation Agreements and programmatic biological opinion and use of the LCAS in assessing the impacts of Federal actions has been effective in removing most threats to the species on these Federal lands. However, amendment or revision of National Forest and BLM land management plans to conserve lynx is still the strongest mechanism needed to ensure lynx and lynx habitat are conserved on National Forest and BLM lands for the long term (see Factor D).

Issue 7: Several commenters suggested that habitat features (such as snow depth, forest composition, prey abundance, elevation, connectivity with lynx populations in Canada) that vary among regions and affect habitat quality may not exist in peripheral areas. Other commenters suggested that generalizations about western lynx populations cannot be applied to the East. Other commenters made recommendations as to how lynx habitat should or should not be defined according to certain vegetation types or descriptions.

Response: Our understanding of lynx habitat requirements is continually refined with ongoing research. We have a better understanding of the habitat conditions based on information from areas where there have been numerous records of lynx over many years and, especially, where resident, breeding populations of lynx have existed over time. Based on the best available information, the key to the presence of lynx populations is adequate snowshoe hare populations. Therefore, habitat conditions and vegetation types that support adequate densities and distribution of snowshoe hares and deep snows are what we consider to be lynx habitat. In general, lynx and snowshoe hare habitats are described as moist boreal forest types that receive deep snow and cold winters (Bittner and Rongstad 1982; McCord and Cardoza 1982; Quinn and Parker 1987; ElliotFisk 1988; Agee 2000; Aubry et al. 2000; McKelvey et al. 2000b; Ruediger et al. 2000). It is well established that lynx are highly mobile and are frequently found in marginal forest types or completely unsuitable habitats that cannot sustain lynx. The fact that individual lynx have been found in such areas does not mean that those areas can support a lynx population or should be considered or managed as ``lynx habitat'' (J. Claar et al., in litt. 2001). To be considered lynx habitat, an area must have the potential to sustain a lynx population over a period of time, which includes supporting the appropriate vegetation composition and structure to support adequate snowshoe hare densities and deep snow where lynx are at a competitive advantage. We recognize
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that the specific vegetation composition of the boreal forest type varies among the regions. Additionally, we recognize that boreal forest types on the periphery of the boreal forest range are found in smaller patches and are only marginally able to support adequate snowshoe hare populations. We conclude records of lynx in these marginal areas or in other areas without lynx habitat are of dispersers. Although there is no evidence that such habitats are able to sustain a resident lynx population, we include all areas with lynx occurrences and lynx habitat, however marginal, within the range of lynx.

Issue 8: One comment suggested lynx historically inhabited the Black Hills of South Dakota as a permanent resident. Another comment suggested northern mountain ranges in New Mexico should be included within the range of lynx.

Response: The scientific literature definitively demonstrates that lynx are specialist predators of snowshoe hares and do not successfully reproduce without an adequate diet of snowshoe hares (Brand and Keith 1979). Snowshoe hares are not indigenous to South Dakota (American Society of Mammalogists Web site). Therefore, we conclude South Dakota naturally could not support a lynx population. We recognize that dispersing lynx have occurred in unsuitable habitats such as in South Dakota; however, we do not include areas of unsuitable habitat within the range of lynx. We do not include New Mexico within the range of lynx because we have no reliable records of native lynx occurring in New Mexico. Lynx are not included on the list of Mammals of New Mexico (American Society of Mammalogists Web site). We do not consider lynx recently released into Colorado that strayed into New Mexico as sufficient reason to include New Mexico within the range of native lynx because there is no evidence habitat in New Mexico historically supported lynx.

Issue 9: A number of comments reported lynx sightings or lynx tracks in New York, New Hampshire, Washington, and Wyoming.

Response: Because lynx are difficult to identify and are often confused with bobcats, we must consider the majority of these reports anecdotal. Nonetheless, because of the existence of reliable lynx records from these States, in addition to the presence of lynx habitat, we include all these States within the range of lynx.

Issue 10: Some comments voiced concern that evidence of lynx in some areas was a result of a survey that was subsequently found to have been contaminated.

Response: In this reanalysis of the basis for our final rule, we did not use any information from that particular survey, the results of which have been rescinded by the author because of the contamination of samples. The majority of the evidence of lynx in the contiguous United States is from trapping records, research, and sightings or track surveys by qualified individuals. Results of positive identification of lynx by DNA acquired during the National Lynx Survey (K. McKelvey, Rocky Mountain Research Station, in litt. 2003) provide additional evidence of lynx. The integrity of the National Lynx Survey has been maintained because of the survey method, DNA analyses, and measures used to ensure quality and reliability.

Issue 11: We received a number of comments suggesting that certain land use activities, particularly timber management practices, adversely impact lynx habitat and are incompatible with lynx survival. Alternatively, one comment suggested that precommercial thinning can be compatible with objectives for highquality lynx habitat.

Response: Timber harvesting can be beneficial, benign, or detrimental to lynx depending on harvest methods, spatial and temporal specifications, and the inherent vegetation potential of the site. Forest practices in lynx habitat that result in or retain a dense understory provide good snowshoe hare habitat that in turn provides good foraging habitat for lynx. In Maine, extensive clear cutting over the past 25 years has resulted in a large amount of the forest currently in a stage of regeneration that is optimal for snowshoe hares and lynx. However, research in Maine has shown that snowshoe hare densities are low in forest stands that have been partially harvested such that there is little understory to provide snowshoe hare habitat. The effects of forest practices on lynx are described and analyzed under Factor A.

Issue 12: Several comments raised concerns about the impacts of various activities on lynx habitat. Activities identified by commenters include roads and trails; agricultural and urban development; offroad vehicle and snowmobile use; ski resort expansion; mining; fire suppression; and grazing.

Response: We address the potential threats to lynx under the ``Summary of Factors Affecting the Species'' section. As a result of our analysis, we found the threat to lynx by some of these activities, such as fire suppression, is low. We found no evidence that some activities, such as forest roads, pose a threat to lynx. Some of the activities suggested, such as mining and grazing, were not specifically addressed because we have no information to indicate they pose threats to lynx.

In considering threats to lynx, one must consider that lynx have evolved to adapt to an everchanging boreal forest and require a mosaic within the boreal forest of appropriate species composition, varying stand ages, and structure to support abundant snowshoe hares and lynx denning habitat. Additionally, one must consider scale. Lynx are highly mobile, moving long distances to find abundant prey, and use a large area on a landscape as demonstrated by the large size of an average lynx home range. To significantly impact a local lynx population, an activity would likely have to occur across a very large area (presumably at least the size of several home ranges), create a homogeneous forest that does not provide the various stand ages, species composition, and structure that are good snowshoe hare and lynx habitat, or result in a barrier that effectively precludes dispersal (see Summary of Factors Affecting the Species section).

Issue 13: One comment suggested that climate change posed a threat to southern lynx populations.

Response: This comment is based on a model that predicted that if average annual snow depths decrease for a long period of time in the Northeast, appropriate lynx habitat would be diminished and could be completely eliminated if appropriate climate conditions did not return, as the author theorized could happen as a result of global warming (Hoving 2001). We conclude the potential for longterm reductions in snow depth because of climate change is speculative at this time and is not a threat to lynx within the foreseeable future (see Factor E).

Issue 14: One comment suggested a Statesanctioned coyote snaring program threatens the lynx population in Maine.

Response: As addressed under Factor D, we recognize that legal trapping, snaring, and hunting for bobcat, coyote, wolverine, and other furbearers create a potential for incidental capture or shooting of lynx. We acknowledge that no reliable recordkeeping exists to determine how frequently such take occurs. Mortality of captured individuals likely has differing impacts on the ability of local populations to persist, depending on the size of the local population and when the take occurs in the population cycle. Lynx still persist throughout their range despite the fact that incidental catch occurred historically, in all likelihood at higher levels than presently occur. Although we are concerned about the
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mortality of lynx that are incidentally captured, we have no information to indicate that the loss of these individuals negatively affects the overall ability of lynx populations to persist. Introduction to Remand Analysis

In the final rule, we found that ``[c]ollectively, the Northeast, Great Lakes and Southern Rockies do not constitute a significant portion of the range of the DPS.'' The following reanalysis of that finding is based on the administrative record, information obtained by the Service during the comment period opened to address the issues on remand, and the Court's opinion in the litigation. As discussed above, we address first whether there were any areas in the range of the lynx outside of the Northern Rockies in which the lynx is in danger of extirpation. Our analysis of whether extirpation will occur is based on the five factors listed in section 4(a)(1) of the Act. For any such areas, we then determine whether they constitute a significant portion of the range of the lynx, based largely on the quantity and quality of the habitat in the portion of the range in question.

Summary of Factors Affecting the Species

Section 4 of the Act and regulations (50 CFR part 424) promulgated to implement the listing provisions of the Act set forth the procedures for adding species to the Federal lists. A species may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1). These factors and their application to the Canada lynx (Lynx canadensis) were discussed in the final rule. Highlighted below are the key points raised in the final rule and the conclusions we made about whether certain activities or conditions threaten Canada lynx to the extent that those points are relevant to the three areas at issue in this remand. If new information changes a statement or conclusion made in the final rule, this point will be made in this analysis. Also discussed below is any new information we received about the five listing factors and their application to lynx during the reopened comment period initiated as a result of the remanded decision. Finally, in this document, we assess the magnitude of the threats to lynx to assist us in determining the status of the species in the areas at issue.

In considering threats to lynx and whether those threats are low, medium, or high, one must consider that lynx have evolved to adapt to an everchanging boreal forest and require a mosaic within the boreal forest of appropriate species composition, varying stand ages, and structure to support abundant snowshoe hares and lynx denning habitat. Additionally, one must consider scale. Lynx are naturally highly mobile, moving long distances to find abundant prey, and use a large area on a landscape; the average home range for a male lynx is 151 km² (58 mi²) (Aubry et al. 2000). In order to affect the suitability of lynx habitat and, in particular, a local lynx population to the extent of putting the population at risk of extinction, an activity would likely have to occur across a very large area (at a minimum the size of several home ranges) and (1) cumulatively result in the conversion of lynx habitat into nonlynx habitat, (2) result in a homogeneous forest that does not provide the various stand ages, species composition, and structure that are good snowshoe hare and lynx habitat, or (3) effectively preclude dispersal. Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

Habitat Quantity and Quality

In assessing habitat quality for lynx, we examine a variety of elements, such as primary prey (snowshoe hare) abundance, forest type, forest structure, snow conditions, denning habitat, inherent habitat patchiness, and connectivity with larger lynx populations and habitat in Canada. We use lynx reproduction and recruitment into the population as additional indicators of habitat quality.

In the following discussions, we describe available information on lynx occurrence, habitat quantity, habitat quality, and other elements that frame our understanding of lynx in the contiguous United States. The complexities of lynx population dynamics and our incomplete understanding of the limited lynx occurrence data, combined with a naturally dynamic and transitional habitat, make it difficult to precisely delineate the historic or current extent of the range of lynx in the contiguous United States. While recognizing these limitations, we use our best professional judgement of the best scientific and commercial data available to make conclusions about the range of the lynx for the purposes of this remand.

Important to understanding the range of lynx in the contiguous United States is the status of the lynx in any given area as a member of a resident, breeding population or as a disperser. While we recognize and agree with McKelvey et al.'s (2000b) caution that lynx occurrence data are too incomplete to infer much beyond simple occurrence, for the purposes of this reevaluation, we feel it necessary to make conclusions about the condition of lynx using our professional assessment of the best scientific and commercial data available. We partially base our conclusions regarding whether lynx in a particular area are resident or dispersers on the record of reliable reports of lynx. We discuss the reliability of records below.

Historic lynx data in the contiguous United States are scarce and exist primarily in the form of trapping records. Many States did not differentiate between bobcats and lynx in trapping records. Therefore, longterm lynx trapping data are not available for most States. Long term trapping data have been used to understand population trends for various species; however, because trapper effort can change across years, trapping returns may not accurately reflect population trends. Data showing few lynx trapped may be the result of low pelt prices or reduced trapper effort, not necessarily a decreased population. However, despite these difficulties, trapping data are the best information available on historic lynx presence throughout much of its range in the contiguous United States.

In the past, surveys designed specifically for lynx were rarely conducted, and many reports (e.g., visual observations, snow tracks) of lynx were collected incidental to other activities. The reliability of many of these records is

FOR FURTHER INFORMATION CONTACT Mark Wilson, Field Supervisor, Montana Field Office (see ADDRESSES), telephone 4064495225; facsimile 406 4495339.