Endangered and Threatened Wildlife and Plants; Notice of Designation of the Gunnison Sage Grouse as a Candidate Species

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of designation of a candidate species.

SUMMARY:

In this document, we present information on the recent addition of the Gunnison sage grouse (Centrocercus minimus) found in Colorado and Utah to the list of candidates for listing under the Endangered Species Act of 1973, as amended. Identification of candidate taxa can assist environmental planning efforts by providing advance notice of potential listings, allowing resource managers to alleviate threats and, thereby, possibly remove the need to list taxa as endangered or threatened. Even if we subsequently list this candidate species, the early notice provided here could result in fewer restrictions on activities by prompting candidate conservation measures to alleviate threats to this species.

We also announce the availability of the candidate and listing priority assignment form for this candidate species. This document describes the status and threats that we evaluated to determine that Gunnison sage grouse warrants consideration for listing, and to assign a listing priority to this species.

We request additional status information that may be available for the Gunnison sage grouse. We will consider this information in evaluating, monitoring, and developing conservation strategies for this species.

DATES:

We will accept comments on this document at any time.

ADDRESSES:

Submit written comments and data regarding the Gunnison sage grouse to the U.S. Fish and Wildlife Service, Western Colorado Field Office, 764 Horizon Drive, South Annex A, Grand Junction, Colorado 81506-3946.

FOR FURTHER INFORMATION CONTACT:

Terry Ireland, at the above address, e-mail <terry_ireland@fws.gov>, or telephone (970) 243-2778.

SUPPLEMENTARY INFORMATION:

Background

The Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that we list taxa of wildlife and plants that are endangered or threatened, based on the best available scientific and commercial information. As part of this program, we also identify taxa that we regard as candidates for listing. Candidate taxa are those taxa for which we have on file sufficient information to support issuance of a proposed rule to list under the Act. In addition to our annual review of all candidate taxa (64 FR 57534; October 25, 1999), we have an on-going review process, particularly to update taxa whose status may have changed markedly.

Section 3 of the Act generally defines an endangered species as any species which is in danger of extinction throughout all or a significant portion of its range, and a threatened species as any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. 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) of the Act.

(A) The present or threatened destruction, modification, or curtailment of the species' habitat or range;

(B) Overutilization of the species for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation affecting the species;

(D) The inadequacy of existing regulatory mechanisms to protect the species; and

(E) Other natural or manmade factors affecting the species' continued existence.

We are required to make the listing determination “solely on the basis of the best scientific and commercial data available” and “taking into account those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species, whether by predator control, protection of habitat and food supply, or other conservation practices, within any area under its jurisdiction, or on the high seas.” Sections 4(a)(1) and 4(b)(1)(A) and our regulations at 50 CFR 424.11(f) require us to consider any State or local laws, regulations, ordinances, programs, or other specific conservation measures that either positively or negatively affect a species' status (i.e., efforts that create, exacerbate, reduce, or remove threats identified through the section 4(a)(1) analysis).

We maintain the list of candidate species for a variety of reasons, including—to provide advance knowledge of potential listings that could affect decisions of environmental planners and developers; to solicit input from interested parties to identify those candidate taxa that may not require protection under the Act or additional taxa that may require the Act's protections; and to solicit information needed to prioritize the order in which we will propose taxa for listing. We encourage consideration of candidate taxa in environmental planning, such as in environmental impact analysis under the National Environmental Policy Act of 1969 (implemented at 40 CFR parts 1500-1508) and in local and Statewide land use planning.

According to our 1983 Listing Priority System (48 FR 43098; September 21, 1983), all species that are candidates for listing are assigned a listing priority number. This system ranks species according to—(1) the magnitude of threats they face, (2) the immediacy of these threats, and (3) the taxonomic distinctiveness of the entity that may be listed. Listing priority numbers range from 1 (highest priority) to 12 (lowest priority). We will complete proposals to list candidate species, based on their listing priority, to the extent that our resources for listing activities and our workload for other listing activities will allow.

This document provides specific explanation for the classification of Gunnison sage grouse as a candidate. It is important to note that candidate assessment is an ongoing function and changes in status should be expected. If we remove taxa from the candidate list, they may be restored to candidate status if additional information supporting such a change becomes available to us. We issue requests for such information in a Candidate Notice of Review published in the Federal Register every year.

Findings

In 1977, Dr. Clait Braun, formerly with the Colorado Division of Wildlife, noticed that sage grouse (Centrocercus sp.) wings collected in the Gunnison Basin of southwestern Colorado were smaller than sage grouse wings collected in northern Colorado. Over the 2 decades since then, Dr. Braun and others have been studying the morphological (Hupp and Braun 1991), behavioral (Young et al. 1994, Braun and Young 1995) and genetic differences (Quinn et al. 1997, Kahn et al. 1999, Oyler-McCance 1999) between the sage grouse. The differences are great enough that the American Ornithologists' Union has determined that the sage grouse in southwestern Colorado are a distinct species, the Gunnison sage grouse (C. minimus). The American Ornithologists' Union included a footnote about the Gunnison sage grouse potentially becoming a distinct species in their latest list of bird species. The July 2000 issue of Auk is planned to contain the American Ornithologists' Union's next list of bird species that will formally include the Gunnison sage grouse as a distinct species (Dr. Richard Banks, National Museum of Natural History, pers. comm. 2000).

Through museum specimens or written accounts, Braun (1995) determined that the Gunnison sage grouse's historic range occurred in southwestern Colorado, southwestern Kansas, northwestern Oklahoma, northern New Mexico, northeastern Arizona, and southeastern Utah. There are currently believed to be seven population areas in Colorado and one population in Utah. The Gunnison Basin breeding population is the largest with up to 3,000 birds. The other 6 populations in Colorado only have 6 to 300 breeding birds, and the Monticello, Utah, population also is only around 120 birds for a total breeding population around 4,000. Long-term trends since at least the 1970s have shown steady declines in the number of males/lek, and one area, Sims Mesa, may have recently been extirpated. The overall population numbers have increased the last 2 to 3 years in the Gunnison Basin; however, this may be attributed to increased survey efforts. The number of males/lek in the Crawford Area population has increased since 1993, though the overall population estimate is no greater than about 320. Other populations appear to be stable in the last 3 to 4 years but remain small.

The Gunnison sage grouse uses a variety of habitats throughout the year but the primary component necessary is species of Artemisia spp. (sagebrush) (Braun 1995). The most important sagebrushes are subspecies of A. tridentata (big sagebrush). Sagebrush is used for hiding and thermal cover as well as a major source of food in the winter (Hupp and Braun 1989). From mid-March to early June males will display on leks (strutting grounds) that are open areas with good visibility (for predator detection) and acoustics (for transmission of male display sounds). After mating, females will select nest sites, typically in relatively tall and dense stands of sagebrush from 200 yards (183 meters) to 5 miles (8 kilometers) away from the leks. Nest sites selected have residual grass and forbs that provide additional hiding cover. Hens with chicks remain in sagebrush uplands if hiding cover is adequate and if food consisting of succulent forbs and insects are available. As chicks mature and vegetation in the uplands desiccates, hens will move their broods to wet meadow areas that retain succulent forbs and insects through the summer (Klebenow 1969, Wallestad 1971). Preferred wet meadow areas also contain tall grasses for hiding and at least 165-yard (150-meter) wide sagebrush stands (Dunn and Braun 1986) along the periphery for hiding and foraging areas. From mid-September into November all sage grouse will use upland areas with 20 percent or greater sagebrush cover and some green forbs. As winter progresses and snow cover is extensive (greater than 80 percent) and deep (greater than 12 inches (30 centimeters)), sage grouse forage in tall sagebrush (greater than 16 inches (41 centimeters)) in valleys and lower flat areas (Hupp and Braun 1989) and roost in shorter sagebrush along ridge tops. Roosting and foraging is typically restricted to south or west facing slopes where snow is often shallower and less extensive (Hupp and Braun 1989). Small foraging areas that have 30-40 percent big sagebrush canopy cover also are important.

Potential threats include reduction in habitat by direct habitat loss, fragmentation, and degradation from building development, road and utility corridors, fences, energy development, conversion of native habitat to hay or other crop fields, alteration or destruction of wetland and riparian areas, inappropriate livestock management, competition for winter range by big game, and creation of large reservoirs.

Other factors affecting the Gunnison sage grouse include fire suppression allowing encroachment of its habitat by Pinus edulis (pinyon) and Juniperus spp. (juniper) invasion, fire suppression resulting in decadent stands of the sagebrush community, overgrazing by elk (Cervus elaphus) and deer (Odocoileus hemionus), drought, disturbance or death by off-highway-vehicles, disturbance by construction projects, harassment from people and pets, continuous noise that impairs acoustical quality of leks, genetic depression, herbicides, pesticides, pollution, and competition for habitat from other species.

Despite development of the Conservation Plans and numerous actions implemented under those Plans to date, all of the threats to the Gunnison sage grouse, under the five listing factors, should be considered non-imminent threat with a high magnitude of occurring, or have potential to occur. In addition, the reduction of about 75 percent of the range and uncertain continued existence of the small, disjunct, populations outside of the Gunnison Basin population, leads us to believe that listing the Gunnison sage grouse as threatened is warranted. Therefore, we have assigned the Gunnison sage grouse a listing a priority of five under our Listing Priority System.

Request for Information

We request you submit any further information on the Gunnison sage grouse as soon as possible or whenever it becomes available. We are seeking the following types of information:

(1) Biological, commercial trade, or other relevant data concerning any threat (or lack thereof) to the Gunnison sage grouse;

(2) Reasons why any habitat of this species should or should not be determined to be critical habitat pursuant to section 4 of the Act;

(3) Additional information concerning the range, distribution, and population size of this species; and,

(4) Current or planned activities in the subject area and their possible impacts on this species.

Information regarding the range, status, habitat needs, and listing priority assignment for the Gunnison sage grouse is available for review by contacting the Service as specified in the ADDRESSES section.

Our practice is to make comments, including names and home addresses of respondents, available for public review during regular business hours. Individual respondents may request that we withhold their home address from the rulemaking record, which we will honor to the extent allowable by law. In certain circumstances, we would withhold from the rulemaking record a respondent's identity, as allowable by law. If you wish for us to withhold your name and/or address, you must state this request prominently at the beginning of your comment. However, we will not consider anonymous comments. We will make all submissions from organizations or businesses, and from individuals identifying themselves as representatives or officials of organizations or businesses, available for public inspection in their entirety.

References Cited

A complete list of all references cited herein, as well as others, is available upon request from the Marine Mammals Management Office (see ADDRESSES section).

References Cited

Braun, C.E. 1995. Distribution and status of sage grouse in Colorado. Prairie Naturalist 27:1-9.

Braun, C.E., and J.R. Young. 1995. A new species of sage grouse from Colorado. Proceedings of the Joint Meeting of The Wilson Ornithological Society and the Virginia Society of Ornithology. Williamsburg, Virginia. Abstract #23.

Commons, M.L., R.K. Baydack, and C.E. Braun. 1999. Sage grouse response to pinyon-juniper management. USDA Forest Service Proceedings RMRS-P-9. 1999:238-239.

Dunn, P.O., and C.E. Braun. 1986. Late summer-spring movements of juvenile sage grouse. Wilson Bulletin 98:83-92.

Hupp, J.W., and C.E. Braun. 1989. Topographic distribution of sage grouse foraging in winter. Journal of Wildlife Management 53:823-829.

Hupp, J.W., and C.E. Braun. 1991. Geographic variation among sage grouse in Colorado. Wilson Bulletin 103:255-261.

Kahn, N.W., C.E. Braun, J.R. Young, S. Wood, D.R. Mata, and T.W. Quinn. 1999. Molecular analysis of genetic variation among large- and small-bodied sage grouse using mitochondrial control-region sequences. Auk 116:819-824.

Klebenow, D.A. 1969. Sage grouse nesting and brood habitat in Idaho. Journal of Wildlife Management 33:649-662.

Oyler-McCance, S.J. 1999. Genetic and habitat factors underlying conservation strategies for Gunnison sage grouse. Abstract of PhD Dissertation. Colorado State University, Fort Collins. 162 pp.

Quinn, T.W., N.W. Kahn, J.R. Young, N.G. Benedict, S. Wood, D. Mata, and C.E. Braun. 1997. Probing the evolutionary history of sage grouse Centrocercus urophasianus populations using mitochondrial DNA sequence. Wildlife Biology 3: 291.

Wallestad, R.O. 1971. Summer movements and habitat use by sage grouse broods in central Montana. Journal of Wildlife Management 35:129-136.

Young, J.R., J.W. Hupp, J.W. Bradbury, and C.E. Braun. 1994. Phenotypic divergence of secondary sexual traits among sage grouse, Centrocercus urophasianus, populations. Animal Behaviour 47:1353-1362.

Author

The author of this notice is Terry Ireland (see ADDRESSES section).

Authority

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