Angeles Volunteer Association

SOURCE:  Federal Register, July 5,  2000.

Proposed Determination of Critical Habitat for the Peninsular Bighorn Sheep

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose designation of critical habitat for the Peninsular bighorn sheep pursuant to the Endangered Species Act of 1973, as amended (Act). The proposed critical habitat boundary encompasses approximately 354,343 hectares (ha) (875,613 acres (ac)) of Peninsular bighorn sheep habitat in Riverside, San Diego, and Imperial Counties, California.
Critical habitat identifies specific areas that have physical and biological features that are essential to the conservation of a listed species, and that may require special management considerations or protection. The primary elements for the bighorn are those habitat components that are essential for the primary biological needs of feeding, sheltering, reproduction, dispersal, and genetic exchange.
If this proposed rule is made final, section 7 of the Act would prohibit destruction or adverse modification of critical habitat by any activity funded, authorized, or carried out by any Federal agency.
Section 4 of the Act requires us to consider economic and other impacts of specifying any particular area as critical habitat. We solicit data and comments from the public on all aspects of this proposal, including data on economic and other impacts of the designation. We may revise this proposal to incorporate or address new information received during the comment period.

DATES: Comments from all interested parties must be received by August 31, 2000. A public hearing is scheduled to be held on July 20, 2000, in Palm Springs, Riverside County, California (see ADDRESSES section below for details). NOTE: On October 16, the deadline for comments was extended from August 31 to November 20.

Comments: You may submit your comments and materials concerning this proposal by any one of several methods.
1. You may mail written comments and information to the Field Supervisor, Carlsbad Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2730 Loker Avenue West, Carlsbad, California 92008.
2. You may hand-deliver written comments to our Carlsbad Fish and Wildlife Office, U.S. Fish and Wildlife Service, 2730 Loker Avenue West, Carlsbad, California 92008.
3. You may send comments by electronic mail (e-mail) to Please submit comments in ASCII file format and avoid the use of special characters and encryption. Please include ``Attn: [RIN number]'' and your name and return address in your e-mail message. If you do not receive a confirmation from the system that we have received your e-mail message, contact us directly by calling our Carlsbad Fish and Wildlife Office at phone number 760-431-9440.
Public Hearings
We have scheduled two public hearings for Thursday, July 20, 2000, from 1 p.m. until 3 p.m. and from 6 p.m. until 8 p.m. at the Wyndham Palm Springs Hotel, 888 E. Tahquitz Canyon Way, Palm Springs, California.
Document Availability
Comments and materials received, as well as supporting documentation used in the preparation of this proposed rule, will be available for public inspection, by appointment, during normal business hours at the Carlsbad Fish and Wildlife Office.
FOR FURTHER INFORMATION CONTACT: Ken Berg, Field Supervisor, Carlsbad Fish and Wildlife Office, at the above address (telephone: 760/431-9440; facsimile 760/431-9624).

The bighorn sheep (Ovis canadensis) is a large mammal (family Bovidae) originally described by Shaw in 1804 (Wilson and Reeder 1993). Wild sheep became established in North America after crossing the Bering land bridge from Eurasia during the late Pleistocene (Geist 1971), and their range has since spread to include desert habitats as far south as northern Mexico (Manville 1980). In North America, two species of wild sheep currently are recognized: the thinhorn sheep (Ovis dalli) and the bighorn sheep (Ovis canadensis). Peninsular bighorn sheep were once divided into seven recognized subspecies based on differences in skull measurements (Cowan 1940, Buechner 1960, Shackleton 1985). These subspecies included Audubon bighorn sheep (Ovis canadensis auduboni), Peninsular bighorn sheep (Ovis canadensis cremnobates), Nelson bighorn sheep (Ovis canadensis nelsoni), Mexican bighorn sheep (Ovis canadensis mexicana), Weems bighorn sheep (Ovis canadensis weemsi), California bighorn sheep (Ovis canadensis californiana), and Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Audubon bighorn sheep are now extinct. As described below, this taxonomy has since been revised. The term ``desert bighorn'' is used to describe bighorn sheep that inhabit dry and relatively barren desert environments and typically includes bighorn sheep subspecies that have, to date, been classified as nelsoni, mexicana, cremnobates, and weemsi (Manville 1980). The validity of these subspecies delineations has been questioned and reassessed. Based on morphometric and genetic analyses, Wehausen and Ramey (1993) synonymized Peninsular bighorn with the subspecies nelsoni, which is the current taxonomy. Bighorn sheep (Ovis canadensis) are found along the Peninsular Mountain Ranges from the San Jacinto Mountains of southern California south into the Volcan Tres Virgenes Mountains near Santa Rosalia, Baja California, Mexico, a total distance of approximately 800 kilometers (km) (500 miles (mi)). The area occupied by the distinct vertebrate population segment covered herein coincides with the range of the former subspecies Ovis canadensis cremnobates in California. The California Fish and Game Commission listed Ovis canadensis cremnobates as ``rare'' in 1971. The designation was changed to ``threatened'' by the California Department of Fish and Game (CDFG) to conform with terminology of the amended California Endangered Species Act. The Peninsular bighorn sheep is similar in appearance to other desert bighorn sheep. The coat is pale brown, and the permanent horns, which become rough and scarred with age, vary in color from yellowish-brown to dark brown. The horns are massive and coiled in males; in females, they are smaller and not coiled. In comparison to other desert bighorn sheep, the Peninsular bighorn sheep is generally described as having paler coloration and having horns with very heavy bases (Cowan 1940). The Peninsular bighorn sheep occurs on steep, open slopes, canyons, and washes in hot and dry desert regions where the land is rough, rocky, and sparsely vegetated. Most of these sheep live between 91 and 1,219 meters (m) (300 and 4,000 feet (ft)) in elevation, where average annual precipitation is less than 10 centimeters (cm) (4 inches (in)) and daily high temperatures average 104 deg. Fahrenheit in the summer. Caves and other forms of shelter (e.g., rock outcrops) are used during inclement weather. Lambing areas are associated with ridge benches or canyon rims adjacent to steep slopes or escarpments. Alluvial fans (sloping masses of gravel, sand, clay, and other sediments that widen out like fans at the base of canyons and washes) are also used for breeding, feeding, and movement. Peninsular bighorn sheep use a wide variety of plant species as their food source (Turner 1976, Scott 1986). Cunningham (1982) determined that the bighorn sheep diet in Carrizo Canyon (at the south end of the U.S. Peninsular Ranges) consisted of 57 percent shrubs, 32 percent herbaceous annuals and perennials, 8 percent cacti, and 2 percent grasses. Scott (1986) and Turner (1976) reported similar diet compositions at the north end of the range. Diet composition varied among seasons (Cunningham 1982, Scott 1986), presumably because of variability in forage availability, selection of specific plant species during different times of the year (Scott 1986), and seasonal movements of bighorn sheep. As with water sources, forage resources near escape terrain may be most valuable to bighorn sheep, especially ewes (Bleich et al. 1997). Peninsular bighorn sheep typically produce only one lamb per year. In the Peninsular Ranges, ewes estimated to be between 2 and 16 years of age have been documented to produce lambs (Ostermann et al. in prep., Rubin et al. in prep.). Rams are believed to be capable of successful breeding as early as 6 months of age (Turner and Hansen 1980). Lambs are born after a gestation of approximately 174 days (Shackleton et al. 1984). Lambing occurs from January through August (Service 1999); however, most lambs are born between February and April. Ewes and lambs frequently occupy steep terrain that provides escape cover and shelter from excessive heat; they tend to congregate near dependable water sources during the summer. Lambs are able to eat native grass within 2 weeks of their birth and are weaned between 4 and 6 months of age. Bighorn ewes exhibit a high degree of site fidelity to their home range; this behavior is learned by their offspring (Geist 1971). By following older animals, young bighorn sheep gather knowledge regarding escape terrain, water sources, and lambing habitat (Geist 1971). Ewes that share portions of a range are likely to be more closely related to each other than they are to other ewes (Festa-Bianchet 1991, Boyce et al. 1999); and are referred to as ``ewe groups'' in this proposal. Rams do not show the same level of site fidelity and tend to range more widely, often moving among ewe groups. As young rams reach 2 to 4 years of age, they follow older rams away from their birth group during the fall breeding period, or rut, and often return after this period (Geist 1971, Festa-Bianchet 1991). From May through October, Peninsular bighorn sheep are dependent on permanent sources of water and are typically more localized in distribution. Bighorn sheep populations aggregate during this period due to a combination of breeding activities and diminishing water sources. Summer concentration areas are associated primarily with[[Page 41407]]dependable water sources, and ideally provide a diversity of vegetation to meet the forage requirements of bighorn sheep. Bighorn sheep are primarily diurnal (Krausman et al. 1985) but may be active at any time of day or night (Miller et al. 1984). Their daily activity pattern includes feeding and resting periods. As bighorn sheep rely on vigilance to detect predators; they benefit from gregariousness and group alertness (Geist 1971, Berger 1978). Within each ewe group, ewes appear to associate with other ewes based on their availability rather than on their matrilineal (descent through the mother) relationships (Festa-Bianchet 1991, Boyce et al. 1999). These subgroups are dynamic; that is, they may split, reform, or change membership on a daily or hourly basis as animals move through their home ranges. The decline of the Peninsular bighorn sheep is attributed to a combination of factors, including: (1) The effects of disease and parasitism (Buechner 1960, DeForge and Scott 1982, DeForge et al. 1982, Jessup 1985, Wehausen et al. 1987, Elliott et al. 1994); (2) low lamb recruitment (DeForge et al. 1982, Wehausen et al. 1987, DeForge et al. 1995); (3) habitat loss, degradation, and fragmentation (Service 1999); and (4) predation (DeForge et al. 1997, Hayes et al. in prep.). Disease has been identified as one of the factors responsible for population declines in the Peninsular Ranges and elsewhere. Analysis of exposure to disease-causing agents between 1978 and 1990 showed that Peninsular bighorn sheep populations and surrounding populations in southern California have higher levels of pathogen exposure than other populations of bighorn sheep in the State (Elliott et al. 1994). However, tests of exposure to pathogens have revealed the presence of antibodies to several infectious disease agents in healthy as well as clinically ill animals (Clark et al. 1993, Elliott et al. 1994; DeForge et al. 1997), and essentially all of the viruses, bacteria, and parasites that have been reported from Peninsular St. sheep appear to be widespread among desert big horn sheep in the western United States (Jessup et al. 1990). All evidence indicates that the influence of disease in the Peninsular Ranges has subsided in more recent years. For example, examinations of big horn sheep throughout the range indicate that most animals are clinically normal (DeForge et al. 1997, Borjesson et al. 2000). The reduced influence of disease on Peninsular big horn sheep (at the same time they are in decline) suggests that other factors, such as predation, habitat loss and modification, and human-related disturbance, currently limit the population. In the Peninsular Ranges, a growing human population and increased activity adjacent to and within big horn sheep habitat are adversely affecting big horn sheep. Human development impacts sheep through habitat loss, fragmentation, or other modification; impacts also extend into big horn sheep habitat beyond the urban edge. These include increased noise, predator attraction, and an increased number of humans and their pets that venture into sheep habitat. Numerous researchers have expressed concern over the impact that human activity in big horn sheep habitat has on big horn sheep (e.g., Jorgensen and Turner 1973, Hicks 1978, Leech 1979, Graham 1980, Cunningham 1982, DeForge and Scott 1982, Gross 1987, Smith and Krausman 1988, Sanchez et al. 1988). Although cases have been cited in which big horn sheep populations did not appear to be impacted by human activity (e.g., Hicks and Elder 1979, Hamilton et al. 1982), numerous researchers, including the previous authors, have documented altered big horn sheep behavior in response to human-related disturbance. In addition to development, a variety of other human activities, such as hiking, mountain biking, horseback riding, camping, hunting, livestock grazing, and use of aircraft and off-road-vehicles, have the potential to disrupt normal big horn sheep social behaviors. Big Horn sheep may also alter their use of essential resources resulting in physiological effects or abandon traditional habitat as a result of human disturbance (McQuivey 1978, MacArthur et al. 1979, Leech 1979, Leslie and Douglas 1980, Graham 1980, MacArthur et al. 1982, Bates and Workman 1983, Miller and Smith 1985, Krausman and Leopold 1986, Krausman et al. 1989, Papouchis et al. 1999). Mountain lion predation is an apparent limiting factor to some ewe groups in the Peninsular Ranges (Hayes et al. In prep.). Reported incidents of lion predation were not common in the past and predation was not considered to be a serious risk to big horn sheep (Weaver and Mensch 1970, Jorgensen and Turner 1975, Cunningham 1982), but the increase in the number of radio-collared big horn sheep since 1993 has increased the detection of such mortalities. Such observations need to be interpreted carefully, however, because it is possible that changes in other causes of mortality (such as diseases) have altered the proportion of mortalities attributed to lion predation. Although predation by other species such as coyotes and bobcats could reduce lamb recruitment, its impact is not well understood. The Peninsular big horn sheep in the United States declined from an estimated 1,171 individuals in 1971 to about 570 individuals in 1991 (Bleach et al. 1992). Recent estimates now number the population at approximately 335 in about eight ewe groups in the wild in the United States There are also two captive populations of Peninsular bighorn sheep. The Living Desert Museum, an educational and zoo facility in Palm Desert, California, maintains a small group (seven adult females and two adult males). The Bighorn Institute, also in Palm Desert, maintains a small captive herd of approximately 15 to 20 animals. This private, nonprofit organization, established in 1982 through a Memorandum of Understanding with the California Department of Fish and Game, conducts research and maintains a breeding herd at its facility. Since 1985, 77 animals from this herd have been released into the wild. Releases have occurred in the northern Santa Rosa Mountains (seventy-four releases from 1985 to 1998) and in the San Jacinto Mountains (3 during 1997) (Ostermann et al. in prep.). The habitat still remaining for the Peninsular bighorn sheep in the United States is managed by: the California Department of Parks and Recreation (416,398 ac or 47 percent); California Department of Fish and Game (25,613 ac or 3 percent), Bureau of Land Management (BLM) (228,568 ac or 26 percent), private landowners (149,906 ac or 17 percent), Trust (20,462 ac or 2 percent) (tribal and allotted lands), U.S. Forest Service (23,073 ac or 3 percent), and other State and local entities (11,593 ac or 1 percent). The Santa Rosa Mountains National Monument has been proposed in the Santa Rosa and San Jacinto Mountains. Since the proposed monument boundaries have not been finalized, we do not know how much of the monument will be within proposed Peninsular bighorn sheep critical habitat. The preliminary proposed monument configuration encompasses a variety of BLM, U.S. Forest Serivce, State, and private lands. Approximately 35% of the proposed critical habitat for Peninsular bighorn sheep overlaps this configuration.

Previous Federal Action

On September 18, 1985, the Service designated the Peninsular bighorn sheep as a category 2 candidate and solicited status information (50 FR 37958). Category 2 included taxa for which the Service had information indicating that proposing to list as endangered or threatened was possibly appropriate, but for which sufficient data on biological vulnerability and threats were not currently available to support a proposed rule. In the January 6, 1989 (54 FR 554), Notice of Review, the Peninsular bighorn sheep was retained in category 2. In 1990, we initiated an internal status review of category 2 species. We completed this review in the spring of 1991; Peninsular bighorn sheep were changed from category 2 to category 1. Category 1 were those taxa for which we had sufficient information on biological vulnerability and threats to support proposals to list them as endangered or threatened. However, we inadvertently omitted this change to category 1 in the November 21, 1991, Animal Notice of Review (56 FR 58804), and the Peninsular bighorn sheep retained category 2 status. Beginning with our February 28, 1996, Notice of Review (61 FR 235), we discontinued the designation of multiple categories of candidates, and we now consider only taxa that meet the definition of former category 1 taxa as candidates for listing. On July 15, 1991, we received a petition from the San Gorgonio Chapter of the Sierra Club to list the Peninsular bighorn sheep as an endangered species. The petition requested that the Service list, through emergency or normal procedures, the Peninsular bighorn sheep throughout its entire range. Alternatively, the petition requested the listing in at least the Santa Rosa and San Jacinto mountains of southern California. The Service used information from the status review and the July 15, 1991, petition to determine that substantial information existed indicating that the Peninsular bighorn sheep may be in danger of extinction throughout all or a significant portion of its range. This finding was made on December 30, 1991, pursuant to section 4(b)(3)(A) of the Act and was published in the Federal Register on May 8, 1992, as a proposed rule to list the Peninsular bighorn sheep as endangered (57 FR 19837). The proposed rule constituted the 1-year finding for the July 15, 1991, petitioned action. The proposed listing status was cited in the subsequent November 15, 1994 (59 FR 58982), and February 28, 1996 (61 FR 7596), Notices of Review. On February 14, 1995, the Sierra Club Legal Defense Fund (plaintiff) filed suit in Federal District Court for the Eastern District of California to compel the Secretary of the Interior and the Director of the Service to make a final determination to list the Peninsular bighorn sheep as an endangered or threatened species. On April 10, 1995, Congress enacted a moratorium prohibiting work on listing actions (Public Law 104-6), thus preventing the Service from taking final listing action on the Peninsular bighorn sheep. The moratorium was lifted on April 26, 1996, by means of a Presidential waiver, at which time limited funding for listing actions was made available through the Omnibus Appropriations Act (Pub. L. No. 104-134, 100 Stat. 1321, 1996). The Service published guidance for restarting the listing program on May 16, 1996 (61 FR 24722). In response to the Sierra Club Legal Defense suit, the District Court issued a stay order on April 10, 1996. On October 15, 1996, the plaintiff asked the Court to lift the stay and require the final Peninsular bighorn sheep listing decision within 30 days. On November 26, 1996, the District Court entered an order denying the plaintiff's request to lift the stay, but certified the issue underlying that denial for interlocutory (temporary) appeal. Due to new information becoming available during the lapse between the original comment period (November 4, 1992) and lifting the listing moratorium, the Service reopened the public comment period on April 7, 1997, for 30 days (62 FR 16518). Because of additional requests, the Service reopened the public comment period again on June 17, 1997, for an additional 15 days (62 FR 32733). To acquire additional information on the status, distribution, and management of bighorn sheep in Baja California, Mexico, the public comment period was reopened on October 27, 1997 (62 FR 55563), for another 15 days. During this third and last comment period extension, the Mexican Government submitted information that they had instituted a new conservation program for bighorn sheep. Due in part to the implementation of this conservation program, the southern boundary of the distinct vertebrate population segment was re-delineated at the United States/Mexico International Border. On March 18, 1998, the bighorn sheep occupying the Peninsular Ranges of southern California were listed as endangered (63 FR 13134) pursuant to the Act. At the time of the listing, we concluded that designation of critical habitat was not prudent. Service regulations (50 CFR 424.12(a)(1)) state that designation of critical habitat is not prudent when one or both of the following situations exist: (1) The identification of critical habitat can be expected to increase the degree of threat to the species, or (2) such designation of critical habitat would not be beneficial to the species. We concluded that critical habitat designation for the Peninsular bighorn sheep was not prudent because both of the described situations existed. We were concerned that publishing detailed maps of bighorn habitat would encourage human disturbance in sensitive areas, such as lambing habitat, rutting areas, and water sources, and result in increased disruption of bighorn sheep. We cited the rapidly growing human population in the Coachella Valley and the increasing recreational interest within bighorn habitat. We also concluded that designation of critical habitat did not add an additional regulatory benefit to bighorn sheep due to the limited Federal regulatory jurisdiction, through section 7 of the Act, for the majority of habitat necessary for conservation of the species. Therefore, we concluded that designation of critical habitat could increase the degree of threats to the species and would not provide any additional protection beyond existing regulatory mechanisms. On December 18, 1998, the Southwest Center for Biological Diversity (Center) and Desert Survivors filed a complaint against the Service alleging that our ``not prudent'' findings were unsubstantiated. On September 17, 1999, we entered into a Settlement Agreement with the Center and Desert Survivors that stipulated a schedule for reviewing our prudency determination and publishing a Recovery Plan for Peninsular bighorn sheep. The schedule included the following dates--draft Recovery Plan, December 31, 1999; new proposed critical habitat determination, June 30, 2000; final Recovery Plan, October 31, 2000; and final determination of critical habitat as not prudent, September 30, 2000, or final critical habitat, by December 31, 2000. On December 31, 1999, we published the draft Recovery Plan for the Bighorn Sheep in the Peninsular Ranges (Service 1999).

Critical Habitat

Critical Habitat Critical habitat is defined in section 3 of the Act as: (i) The specific areas within the geographic area occupied by a species, at the time it is listed in accordance with the Act, on which are found those physical or biological features (I) essential to the conservation of the species and (II) that may require special management considerations or protection; and (ii) specific areas outside the geographic area occupied by a species at the time it is listed, upon[[Page 41409]]a determination that such areas are essential for the conservation of the species. ``Conservation'' means the use of all methods and procedures that are necessary to bring an endangered or a threatened species to the point at which listing under the Act is no longer necessary. We have reconsidered our previous prudency determination regarding the threats posed by a potential increase in disturbance of especially sensitive bighorn areas, such as lambing areas. Peninsular bighorn sheep distribution is not solely dependent on isolated habitat features, but requires a continuum of essential resources that allows the species to adapt to natural and unnatural environmental processes. Though bighorn sheep exhibit a high degree of site fidelity to their home range, their distributions are continually changing in response to changes in the environment. Peninsular bighorn sheep are considered a metapopulation, which is a group of smaller populations that occasionally exchange individuals and/or genetic material, usually through ram movement. As in any metapopulation, habitat restriction and fragmentation can impede dispersal and recolonization potential, thereby degrading the ability of the sub populations to interact. This is particularly true for large mammals that range widely to locate and exploit unpredictably changing sources of food, water, and shelter. Accordingly, we have used an ecosystem approach to delineate critical habitat that includes all of the essential habitat components, and does not highlight localized bighorn areas. Consequently, we conclude that designating critical habitat is not expected to increase the degree of threat from human activities. Furthermore, we have determined that the limited section 7 nexus for the majority of Peninsular bighorn habitat, as discussed in the final listing rule, is not, by itself, an adequate basis for making a ``not prudent'' finding. Designation of critical habitat will also provide some educational benefit by identifying the range-wide habitat essential to the conservation of the species, and help provide a focus for interagency recovery efforts. Therefore, we now conclude that the benefits of designating critical habitat outweigh the potential negative impacts. Critical habitat receives protection under the Act through the prohibition against destruction or adverse modification of critical habitat as set forth under section 7 of the Act with regard to actions carried out, funded, or authorized by a Federal agency. Section 7 also requires conferences on Federal actions that are likely to result in the adverse modification or destruction of proposed critical habitat. Aside from the protection that may be provided under section 7, the Act does not provide other forms of protection to lands designated as critical habitat. Critical habitat designation would not afford any protection under the Act to activities on private or other non-Federal lands that do not involve a Federal action. Designating critical habitat does not, in itself, lead to recovery of a listed species. Designation does not create a management plan, set aside areas as preserves, establish numerical population goals, prescribe specific management actions (inside or outside of critical habitat), or directly affect areas not designated as critical habitat. Critical habitat identifies specific areas that have features that are essential to the conservation of a listed species and that may require special management considerations or protection. Specific management recommendations for areas designated as critical habitat are most appropriately addressed in recovery plans and management plans, and through section 7 consultation and section 10 permits.

[Please refer to Federal Register to view the remainder of this announcement.]

News Releases
AVA Home Page