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Department of the Interior Fish and Wildlife Service Thursday, February 1, 2001 Part IV Department of the Interior Fish and Wildlife Service 50 CFR Part 17 Endangered and Threatened Wildlife and Plants; Final Determination of Critical Habitat for Peninsular Bighorn Sheep; Final Rule VerDate 11<MAY>2000 12:04 Jan 31, 2001 Jkt 194001 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\FR\FM\01FER4.SGM pfrm03 PsN: 01FER4 8650 Federal Register / Vol. 66, No. 22 / Thursday, February 1, 2001 / Rules and Regulations DEPARTMENT OF THE INTERIOR (telephone: 760/431–9440; facsimile (CDFG) to conform with terminology of 760/431–9624). the amended California Endangered Fish and Wildlife Service SUPPLEMENTARY INFORMATION: Species Act. Background The Peninsular bighorn sheep is 50 CFR Part 17 The bighorn sheep (Ovis canadensis) similar in appearance to other desert is a large mammal (family Bovidae) bighorn sheep. The coat is pale brown, RIN 1018–AG17 originally described by Shaw in 1804 and the permanent horns, which (Wilson and Reeder 1993). Wild sheep become rough and scarred with age, Endangered and Threatened Wildlife became established in North America vary in color from yellowish-brown to and Plants; Final Determination of after crossing the Bering land bridge dark brown. The horns are massive and Critical Habitat for Peninsular Bighorn from Eurasia during the late Pleistocene coiled in males; in females, they are Sheep (Geist 1971), and their range has since smaller and not coiled. In comparison to spread to include desert habitats as far other desert bighorn sheep, the AGENCY: Fish and Wildlife Service, Peninsular bighorn sheep is generally Interior. south as northern Mexico (Manville 1980). In North America, two species of described as having paler coloration and ACTION: Final rule. wild sheep currently are recognized: the having horns with very heavy bases thinhorn sheep (Ovis dalli) and the (Cowan 1940). SUMMARY: We, the U.S. Fish and Peninsular bighorn sheep occur on bighorn sheep (Ovis canadensis). Wildlife Service (Service), designate steep, open slopes, canyons, and washes Bighorn sheep were once divided into critical habitat for Peninsular bighorn in hot and dry desert regions where the seven recognized subspecies based on sheep pursuant to the Endangered land is rough, rocky, and sparsely Species Act of 1973, as amended (Act). differences in skull measurements vegetated. Most of these sheep live A total of approximately 341,919 (Cowan 1940; Buechner 1960; between 91 and 1,219 meters (m) (300 hectares (844,897 acres) in Riverside, Shackleton 1985). These subspecies and 4,000 feet (ft)) in elevation, where San Diego, and Imperial counties, included Audubon bighorn sheep (Ovis average annual precipitation is less than California, are designated as critical canadensis auduboni), Peninsular 10 centimeters (cm) (4 inches (in)) and habitat for Peninsular bighorn sheep. bighorn sheep (O. c. cremnobates), daily high temperatures average 104° Critical habitat identifies specific Nelson bighorn sheep (O. c. nelsoni), Fahrenheit in the summer. Caves and areas that have the physical and Mexican bighorn sheep (O. c. other forms of shelter (e.g., rock biological features that are essential to mexicana), Weems bighorn sheep (O. c. outcrops) are used during inclement the conservation of a listed species, and weemsi), California bighorn sheep (O. c. weather and for shade during the hotter that may require special management californiana), and Rocky Mountain months. Lambing areas are associated considerations or protection. The bighorn sheep (O. c. canadensis). with ridge benches or canyon rims primary constituent elements for the Audubon bighorn sheep are now adjacent to steep slopes or escarpments. Peninsular bighorn sheep are those extinct. As described below, bighorn Alluvial fans (sloping deposits of gravel, habitat components that are essential for sheep taxonomy has since been revised. sand, clay, and other sediments that the primary biological needs of feeding, The term ‘‘desert bighorn’’ is used to spread fan-like at the base of canyons sheltering, reproduction, dispersal, and describe bighorn sheep that inhabit dry and washes) are also used for breeding, genetic exchange. All areas designated and relatively barren desert feeding, and movement. as critical habitat for the Peninsular environments and typically includes Peninsular bighorn sheep use a wide bighorn sheep contain one or more of bighorn sheep subspecies that have, to variety of plant species as their food the primary constituent elements. date, been classified as Ovis canadensis source (Turner 1976; Scott 1986). Section 7 of the Act prohibits nelsoni, O. c. mexicana, O. c. Cunningham (1982) determined that the destruction or adverse modification of cremnobates, and O. c. weemsi bighorn sheep diet in Carrizo Canyon (at critical habitat by any activity funded, (Manville 1980). The validity of these the south end of the U.S. Peninsular authorized, or carried out by any subspecies delineations has been Ranges) consisted of 57 percent shrubs, Federal agency. Section 4 of the Act questioned and reassessed. Based on 32 percent herbaceous annuals and requires us to consider economic and morphometric and genetic analyses, perennials, 8 percent cacti, and 2 other impacts of specifying any Wehausen and Ramey (1993) percent grasses. Scott (1986) and Turner particular area as critical habitat. We synonymized Peninsular bighorn with (1976) reported similar diet solicited data and comments from the the subspecies nelsoni, which is the compositions at the north end of the public on all aspects of the proposed current taxonomy. range. Diet composition varied among rule and economic analysis. In the Peninsular Mountain Ranges, seasons (Cunningham 1982; Scott 1986), DATES: This rule will be effective March bighorn sheep are found from the San presumably because of variability in 5, 2001. Jacinto Mountains of southern forage availability, selection of specific California south into the Volcan Tres plant species during different times of ADDRESSES: Comments and materials Virgenes Mountains near Santa Rosalia, the year (Scott 1986), and seasonal received, as well as supporting Baja California, Mexico, a total distance movements of bighorn sheep. As documentation used in the preparation of approximately 800 kilometers (km) discussed in the approved Recovery of this final rule, will be available for (500 miles (mi)). The area occupied by Plan (Service 2000), the high metabolic public inspection, by appointment, the distinct vertebrate population demands of ewes during pregnancy and during normal business hours at the segment covered herein coincides with lactation require the seasonal Carlsbad Fish and Wildlife Office, U.S. the range of the former subspecies Ovis availability of high protein forage Fish and Wildlife Service, 2730 Loker canadensis cremnobates in California. sources such as found on the deeper, Avenue West, Carlsbad, California The California Fish and Game more productive soils of alluvial fans 92008. Commission listed O. c. cremnobates as and canyon bottoms. FOR FURTHER INFORMATION CONTACT: ‘‘rare’’ in 1971. The designation was Peninsular bighorn sheep typically Field Supervisor, Carlsbad Fish and changed to ‘‘threatened’’ by the produce only one lamb per year. In the Wildlife Office, at the above address California Department of Fish and Game Peninsular Ranges, ewes estimated to be VerDate 11<MAY>2000 12:04 Jan 31, 2001 Jkt 194001 PO 00000 Frm 00002 Fmt 4701 Sfmt 4700 E:\FR\FM\01FER4.SGM pfrm03 PsN: 01FER4 Federal Register / Vol. 66, No. 22 / Thursday, February 1, 2001 / Rules and Regulations 8651 between 2 and 16 years of age have been at any time of day or night (Miller et al. activity adjacent to and within bighorn documented to produce lambs 1984). Their daily activity pattern sheep habitat are adversely affecting (Ostermann et al. in press; Rubin et al. includes feeding and resting periods. As bighorn sheep by altering their normal 2000). Lambs are born after a gestation bighorn sheep rely on vigilance to detect behavior, which has evolved in the of approximately 174 days (Shackleton predators, they benefit from absence of excessive human et al. 1984). Lambing occurs from gregariousness and group alertness disturbance. Human development January through August (Service 1999); (Geist 1971; Berger 1978). Within each impacts sheep through habitat loss, however, most lambsare born between ewe group, ewes appear to associate fragmentation, or other modifications. February and April (Rubin et al. 2000). with other ewes based on their At least 7,490 hectares (ha) (18,500 acres Ewes and lambs frequently occupy steep availability rather than on their (ac) or about 30 square miles) of suitable terrain that provides escape cover and matrilineal (descent through the mother) habitat has been lost to urbanization and shelter from excessive heat; they tend to relationships (Festa-Bianchet 1991; agriculture along the urban interface congregate near dependable water Boyce et al. 1999). These subgroups are between Palm Springs and La Quinta sources during the summer. Lambs are dynamic, that is, they may split, reform, (Service 2000). Much of the lost habitat able to eat native forage within 2 weeks or change membership on a daily or consisted of low elevation alluvial fans of their birth and are weaned between hourly basis as animals move through and washes that furnished important 4 and 6 months of age. their home ranges. sources of nutrients to ewes while they Bighorn ewes exhibit a high degree of The decline of the Peninsular bighorn were rearing their lambs. Moreover, in site fidelity to their home range, and sheep is attributed to a combination of the northern Santa Rosa Mountains, this behavior is learned by their factors, including: (1) the effects of from 1991 to 1996, thirty-four percent of offspring (Geist 1971). Ewes that share disease and parasitism (Buechner 1960; adult mortalities appear to have been portions of a range, referred to as ‘‘ewe DeForge and Scott 1982; DeForge et al. directly caused by urbanization. Five groups’’ in this rule, are likely to be 1982; Jessup 1985; Wehausen et al. bighorn sheep were killed by cars; 5 more closely related to each other than 1987; Elliott et al.
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