Appendix O – Determination of Threatened Status for the Contiguous U.S

Appendix O – Determination of Threatened Status for the Contiguous U.S. Distinct Population Segment of the Canada Lynx and Related Rule; Final Rule 533 534 Friday, March 24, 2000 Part V Department of the Interior Fish and Wildlife Service 50 CFR Part 17 Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for the Contiguous U.S. Distinct Population Segment of the Canada Lynx and Related Rule; Final Rule VerDate 20<MAR>2000 19:53 Mar 23, 2000 Jkt 190000 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\FR\FM\24MRR2.SGM pfrm01 PsN: 24MRR2 16052 Federal Register / Vol. 65, No. 58 / Friday, March 24, 2000 / Rules and Regulations DEPARTMENT OF THE INTERIOR long legs and large feet make it highly the lynx is highly adapted (Ruggiero et adapted for hunting in deep snow. al. 1999b). Fish and Wildlife Service The bobcat (Lynx rufus) is a North We consider lynx in the contiguous American relative of the lynx. United States to be part of a larger 50 CFR Part 17 Compared to the lynx, the bobcat has metapopulation whose core is located in RIN 1018±AF03 smaller paws, shorter ear tufts, and a the northern boreal forest of central more spotted pelage (coat), and only the Canada; lynx populations emanate from Endangered and Threatened Wildlife top of the tip of the tail is black. The this area (Buskirk et al. 1999b; and Plants; Determination of paws of the lynx have twice the surface McKelvey et al. 1999a, 1999b). The Threatened Status for the Contiguous area as those of the bobcat (Quinn and boreal forest extends south into the U.S. Distinct Population Segment of Parker 1987). The lynx also differs in its contiguous United States along the the Canada Lynx and Related Rule body proportions in comparison to the Cascade and Rocky Mountain Ranges in bobcat. Lynx have longer legs, with hind the West, the western Great Lakes AGENCY: Fish and Wildlife Service, legs that are longer than the front legs, Region, and along the Appalachian Interior. giving the lynx a ``stooped'' appearance Mountain Range of the northeastern ACTION: Final rule. (Quinn and Parker 1987). Bobcats are United States. At its southern margins, largely restricted to habitats where deep the boreal forest becomes naturally SUMMARY: We, the U.S. Fish and snows do not accumulate (Koehler and fragmented into patches of varying size Wildlife Service (Service), determine Hornocker 1991). Hybridization as it transitions into other vegetation threatened status for the contiguous U.S. (breeding) between lynx and bobcat is types. These southern boreal forest Distinct Population Segment of the not known (Quinn and Parker 1987). habitat patches are small relative to the Canada lynx (Lynx canadensis), with a Classification of the Canada lynx (also extensive northern boreal forest of special rule, pursuant to the Endangered Canada and Alaska, which constitutes Species Act of 1973, as amended. This called the North American lynx) has been subject to revision. In accordance the majority of the lynx range. population segment occurs in forested Many of these southern boreal forest with Wilson and Reeder (1993), we portions of the States of Colorado, habitat patches within the contiguous currently recognize the lynx in North Idaho, Maine, Michigan, Minnesota, United States are able to support America as Lynx canadensis. We Montana, New Hampshire, New York, resident populations of lynx and their previously used the latin name L. lynx Oregon, Utah, Vermont, Washington, primary prey species. It is likely that canadensis for the lynx (Jones et al. and Wisconsin. The contiguous U.S. some of the habitat patches act as 1992; S. Williams, Texas Tech Distinct Population Segment of the lynx sources of lynx (recruitment is greater is threatened by the inadequacy of University, pers. comm. 1994). Other than mortality) that are able to disperse existing regulatory mechanisms. Current scientific names still in use include and potentially colonize other patches U.S. Forest Service Land and Resource Felis lynx or F. lynx canadensis (Jones (McKelvey et al. 1999a). Other habitat Management Plans include programs, et al. 1986; Tumlison 1987). patches act as ``sinks'' where lynx practices, and activities within the The historical and present range of mortality is greater than recruitment and authority and jurisdiction of Federal the lynx north of the contiguous United lynx are lost from the overall land management agencies that may States includes Alaska and that part of population. The ability of naturally threaten lynx or lynx habitat. The lack Canada that extends from the Yukon dynamic habitat to support lynx of protection for lynx in these Plans and Northwest Territories south across populations may change as the habitat render them inadequate to protect the the United States border and east to undergoes natural succession following species. New Brunswick and Nova Scotia. In the natural or manmade disturbances (i.e., contiguous United States, lynx fire, clearcutting). In addition, EFFECTIVE DATE: April 24, 2000. historically occurred in the Cascades fluctuations in the prey populations ADDRESSES: The complete file for this Range of Washington and Oregon; the may cause some habitat patches to rule is available for inspection, by Rocky Mountain Range in Montana, change from being sinks to sources and appointment, during normal business Wyoming, Idaho, eastern Washington, vice versa. Throughout this document, hours at the Montana Field Office, U.S. eastern Oregon, northern Utah, and we use the term ``resident population'' Fish and Wildlife Service, 100 N. Park Colorado; the western Great Lakes to refer to a group of lynx that has Avenue, Suite 320, Helena, Montana Region; and the northeastern United exhibited long-term persistence in an 59601. States region from Maine southwest to area based on a variety of factors, such FOR FURTHER INFORMATION CONTACT: New York (McCord and Cardoza 1982; as evidence of reproduction, successful Kemper McMaster, Field Supervisor, Quinn and Parker 1987) (see recruitment into the breeding cohort, Montana Field Office (see ADDRESSES ``Distribution and Status'' section). and maintenance of home ranges. We section) (telephone 406/449±5225; In the contiguous United States, the use the word ``transient'' to refer to a facsimile 406/449±5339). distribution of the lynx is associated lynx moving from one place to another with the southern boreal forest, within suitable habitat. Another word Background comprising of subalpine coniferous we use throughout the document is The Canada lynx, hereafter referred to forest in the West and primarily mixed ``dispersing,'' which refers to lynx that as lynx, is a medium-sized cat with long coniferous/deciduous forest in the East have left suitable habitat for various legs; large, well-furred paws; long tufts (Aubry et al. 1999) (see ``Distribution reasons, such as competition or lack of on the ears; and a short, black-tipped and Status'' section); whereas in Canada food. When dispersing lynx leave tail (McCord and Cardoza 1982). Adult and Alaska, lynx inhabit the classic suitable habitat and enter habitats that males average 10 kilograms (22 pounds) boreal forest ecosystem known as the are unlikely to sustain lynx, these in weight and 85 centimeters (33.5 taiga (McCord and Cardoza 1982; Quinn individuals are considered lost from the inches) in length (head to tail), and and Parker 1987; Agee 1999; McKelvey metapopulations unless they return to females average 8.5 kilograms (19 et al. 1999b). Within these general forest boreal forest. pounds) and 82 centimeters (32 inches) types, lynx are most likely to persist in Lynx use large woody debris, such as (Quinn and Parker 1987). The lynx's areas that receive deep snow, for which downed logs and windfalls, to provide VerDate 20<MAR>2000 18:27 Mar 23, 2000 Jkt 190000 PO 00000 Frm 00002 Fmt 4701 Sfmt 4700 E:\FR\FM\24MRR2.SGM pfrm04 PsN: 24MRR2 Federal Register / Vol. 65, No. 58 / Friday, March 24, 2000 / Rules and Regulations 16053 denning sites with security and thermal disease, fire, wind, ice, or insects, and 1999b). Hodges (1999b) proposes that cover for kittens (McCord and Cardoza the understory grows (Buskirk et al. northern and southern hare populations 1982; Koehler 1990; Koehler and Brittell 1999b). Lynx concentrate their hunting have similar cyclic dynamics but that in 1990; Squires and Laurion 1999; J. activities in areas where hare activity is southern areas both peak and low Organ, U.S. Fish and Wildlife Service, relatively high (Koehler et al. 1979; densities are lower than in the north. in litt. 1999). For lynx den sites, the age Parker 1981; Ward and Krebs 1985; Snowshoe hares are generally associated of the forest stand does not seem as Major 1989; Murray et al. 1994; with conifer forest cover types (Hodges important as the amount of downed, O'Donoghue et al. 1997, 1998a). 1999b). Relatively low snowshoe hare woody debris available (Mowat et al. The association between lynx and densities at southern latitudes are likely 1999). In Washington, lynx used Pinus snowshoe hare is considered a classic a result of the naturally patchy, contorta (lodgepole pine), Picea spp. predator-prey relationship (Saunders transitional boreal habitat at southern (spruce), and Abies lasiocarpa 1963; van Zyll de Jong 1966; Quinn and latitudes that prevents hare populations (subalpine fir) forests older than 200 Parker 1987). In northern Canada and from achieving densities similar to those years with an abundance of downed Alaska, lynx populations fluctuate on of the expansive northern boreal forest woody debris for denning (Koehler approximately 10-year cycles that (Wolff 1980; Buehler and Keith 1982; 1990). A den site in Wyoming was follow the cycles of hare populations Koehler 1990; Koehler and Aubry 1994). located in a mature subalpine fir/ (Elton and Nicholson 1942; Hodges Additionally, the presence of more lodgepole pine forest with abundant 1999a, 1999b; McKelvey et al.

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