02-32523. Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Mono Basin Area Sage Grouse as Endangered

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 90-day finding on a petition to list the Mono Basin area sage grouse (Centrocercus urophasianus phaios) under the Endangered Species Act of 1973, as amended. We find the petition does not present substantial scientific or commercial information indicating that listing this species may be warranted.

DATES:

The finding announced in this document was made December 26, 2002.

ADDRESSES:

The complete file for this finding is available for inspection, by appointment, during normal business hours at the U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office, 1340 Financial Boulevard, Suite 234, Reno, NV 89502.

FOR FURTHER INFORMATION CONTACT:

Robert D. Williams, Field Supervisor, Nevada Fish and Wildlife Office (see ADDRESSES) (telephone [phone]; facsimile 775/861-6301).

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered Species Act of 1973, (Act) as amended (16 U.S.C. 1531 et seq.), requires that we make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information indicating that the petitioned action may be warranted. This finding is to be based on all information available to us at the time we make the finding. To the maximum extent practicable, this finding is to be made within 90 days of our receipt of the petition, and notice of this finding is to be published promptly in the Federal Register. Our standard for substantial information within the Code of Federal Regulations (CFR) with regard to a 90-day petition finding is “that amount of information that would lead a reasonable person to believe that the measure proposed in the petition may be warranted” (50 CFR 424). If the finding is that substantial information was presented, we are required to promptly commence a review of the status of the involved species, if one has not already been initiated, under our internal candidate assessment process.

On January 2, 2002, we received a petition, dated December 28, 2001, from the Institute for Wildlife Protection requesting that the greater sage grouse (Centrocercus urophasianus phaios) occurring in the Mono Basin area of Mono County, California, and Lyon County, Nevada, be emergency listed as an endangered distinct population segment (DPS) under the Act. The petition clearly identified itself as such and contained the name, address, and signature of the petitioning organization's representative. Accompanying the petition was information related to the taxonomy, life history, demographics, movements, habitats, threats, and the past and present distribution of the greater sage grouse. The petitioner contends that the sage grouse occurring in the Mono Basin are genetically unique from the birds that occur in the rest of the range of the species and possesses other distinctive features as well. Also, the petitioner contends that sage grouse in the Mono Basin are imminently threatened with extinction. In order to determine if substantial information is available to indicate that the petitioned action may be warranted, the Service has reviewed the following: the subject petition, literature cited in the petition, information provided by recognized experts or agencies cited in the petition, and information otherwise available in Service files.

The petitioner's request is to list the Mono Basin area population of the greater sage grouse (Centrocercus urophasianus phaios) as a DPS. However, the scientific name used by the petitioner to identify the greater sage grouse is incorrect. The correct scientific name for the greater sage grouse is Centrocercus urophasianus, whereas C. u. phaios is the western subspecies of the greater sage grouse and does not occur in the Mono Basin (Aldrich 1946, 1963; American Ornithologists' Union (AOU) 1957; Johnsgard 1973). The sage grouse that occurs in the Mono Basin area has been described as the eastern subspecies of the greater sage grouse (C. urophasianus urophasianus) (Aldrich 1946, 1963; AOU 1957; Johnsgard 1973).

The following information regarding the description and natural history of the sage grouse has been condensed from the following sources: Aldrich 1963, Johnsgard 1973, Connelly et al. 1988, Fischer et al. 1993, Drut 1994, Western Sage and Columbian Sharp-Tailed Grouse Workshop 1996 and 1998, Schroeder et al. 1999, and Governor Guinn's Sage Grouse Conservation Planning Team 2001.

The sage grouse is the largest North American grouse species. Adult males range in size from 66 to 76 centimeters (cm) (26 to 30 inches (in)) and weigh between 2 and 3 kilograms (kg) (4 and 7 pounds (lb)); adult females range in size from 48 to 58 cm (19 to 23 in) and weigh between 1 and 2 kg (2 and 4 lb). Males and females have dark grayish-brown body plumage with many small gray and white speckles, fleshy yellow combs over the eyes, long pointed tails, and dark-green toes. Males also have blackish chin and throat feathers, conspicuous phylloplumes (specialized erectile feathers) at the back of the head and neck, and white feathers forming a ruff around the neck and upper belly. During breeding displays, males also exhibit olive-green apteria (fleshy bare patches of skin) on their breasts.

Sage grouse depend on a variety of shrub steppe habitats throughout their life cycle, and are particularly tied to several species of sagebrush (Artemesia spp.). Throughout much of the year, adult sage grouse rely on sagebrush to provide roosting cover and food. During the winter they depend almost exclusively on sagebrush for food. The type and condition of shrub steppe plant communities strongly affect habitat use by sage grouse populations. However, these populations also exhibit strong site fidelity (loyalty to a particular area). Sage grouse populations may disperse up to 160 kilometers (km) (100 miles (mi)) between seasonal use areas; however, average population movements are generally less than 34 km (21 mi). Sage grouse are also capable of dispersing over areas of unsuitable habitat.

During the spring breeding season, primarily during the morning hours just after dawn, male sage grouse gather together and perform courtship displays on areas called leks (areas where animals assemble and perform courtship displays). Areas of bare soil, short grass steppe, windswept ridges, exposed knolls, or other relatively open sites may serve as leks. Leks range in size from less than 0.4 hectare (ha) (1 acre (ac)) to more than 40 ha (100 ac) and can host several to hundreds of males. Some leks are used for many years. These “historic” leks are typically larger than, and often surrounded by, smaller “satellite” leks, which may be less stable in size and location within the course of one year and between two or more years. A group of leks where males and females may interact within a breeding season or between years is called a lek complex. Males defend individual territories within leks and perform elaborate displays with their specialized plumage and vocalizations to attract females for mating.

Females may travel up to 35 km (22 mi) after mating, and typically select nest sites under sagebrush cover, although other shrub or bunchgrass species are sometimes used. Nests are relatively simple and consist of scrapes on the ground. Clutch sizes range from 6 to 13 eggs. Nest success ranges from 10 to 63 percent and is relatively low compared to that of other prairie grouse species. Shrub canopy and grass cover provide concealment for sage grouse nests and young, and may be critical for reproductive success.

Sage grouse typically live between 1 and 4 years; however, sage grouse up to 10 years of age have been recorded in the wild. The annual mortality rate for sage grouse is roughly 50 to 55 percent, which is relatively low compared to rates for other prairie grouse species. Females generally have a higher survival rate than males, which accounts for a female-biased sex ratio in adult birds.

Prior to European expansion into western North America, sage grouse (C. urophasianus) were believed to occur in the States of Washington, Oregon, California, Nevada, Idaho, Montana, Wyoming, Colorado, Utah, South Dakota, North Dakota, Kansas, Oklahoma, Nebraska, New Mexico, Arizona, and the Canadian provinces of British Columbia, Alberta, and Saskatchewan (Schroeder et al. 1999). Currently, sage grouse occur in 11 States and 2 Canadian provinces, ranging from extreme southeastern Alberta and southwestern Saskatchewan, south to western Colorado, and west to eastern California, Oregon, and Washington. In addition, sage grouse occur in southern Idaho, the northern two-thirds of Nevada, parts of Utah, most of Wyoming, southern and eastern Montana, and extreme western North and South Dakota. Sage grouse have been extirpated from Nebraska, Kansas, Oklahoma, New Mexico, Arizona, and British Columbia (Schroeder et al. 1999).

Rangewide, sage grouse distributions have declined in a number of areas, most notably along the northern and northwestern periphery and in the center of their historic range. There may have been between roughly 1.6 million and 16 million sage grouse rangewide prior to European expansion across western North America (65 FR 51578). The Western States Sage Grouse Technical Committee (WSSGTC) (1999) estimated that there may have been about 1.1 million birds in 1800. Braun (1998) estimated that the 1998 rangewide spring population numbered about 157,000 sage grouse. More recent estimate puts the number of sage grouse rangewide at between roughly 100,000 and 500,000 birds (65 FR 51578). Sage grouse population levels may have declined from historic to recent times between 69 and 99 percent (65 FR 51578). WSSGTC (1999) estimates the decline from historic times to the present day may have been about 86 percent.

Apparently, much of the overall decline in sage grouse populations occurred from the late 1800s to the mid 1900s (Hornaday 1916, Crawford 1982, Drut 1994, Washington Department of Fish and Wildlife (WDFW) 1995, Braun 1998, Schroeder et al. 1999). Other declines in sage grouse populations apparently occurred in the 1920s and 1930s, and then again in the 1960s and 1970s (Connelly and Braun 1997).

Mono Basin Area Sage Grouse

Sage grouse in the Mono Basin area of California historically occurred in most of Mono County, the far eastern part of Alpine County, and in northern Inyo County (Leach and Hensley 1954, Hall 1995). By 1995, suitable habitat within this area had declined approximately 71 percent from an estimated historic level of 916,571 ha (2,264,889 ac) to 265,758 ha (656,700 ac) (Hall 1995). Most (93 percent) of the remaining sage grouse distribution and all known leks in the Mono Basin part of California occur in Mono County (Hall 1995, BLM 2002). Lek areas in Mono County include Fales, Bodie Hills, Parker, Sagehen, Adobe, Long Valley, and the White Mountains. From 1995 to 2002, California Department of Fish and Game (CDFG) spring population estimates for sage grouse in Mono County varied from 664 to 1,435 birds with an average of 1,075 birds (Sam Blankenship, CDFG, pers. comm. 2002).

In Nevada Esmeralda, Mineral, Lyon, and Douglas Counties share borders with Mono County, and this could be characterized as the Mono Basin area. Historically, sage grouse occurred in all four of these Nevada counties (Gullion and Christensen 1957). Sage grouse habitat in this part of Nevada has declined from historic levels but the amount of loss is not known (San Stiver, Nevada Division of Wildlife (NDOW), pers. comm. 2002). Active leks are present in all these counties except Esmeralda County. Active leks occur in the following areas: Ninemile and Mt. Grant areas of Mineral County; the Sweetwater, Desert Creek, and North Pine Nuts area of Lyon County; and the South Pine Nuts area of Douglas County (BLM 2002). No sage grouse spring population estimates are available for Douglas County. NDOW was unable to provide 2002 population estimates for Mineral and Lyon Counties.

The petitioner requested that we emergency list the Mono Basin area sage grouse as an endangered DPS of the species under the Act. Under our DPS policy (61 FR 4722), we use three elements to assess whether a population under consideration for listing may be recognized as a DPS: (1) A population segment's discreteness from the remainder of the taxon; (2) the population segment's significance to the taxon to which it belongs; and (3) “[t]he population segment's conservation status in relation to the Act's standards for listing (i.e., is the population segment, when treated as if it were a species, endangered or threatened.)”. If we determine that a population being considered for listing may represent a DPS, then the level of threat to the population is evaluated based on the five listing factors established by the Act to determine if listing it as either threatened or endangered may be warranted.

A population segment of a vertebrate species may be considered discrete if it satisfies either of the following conditions. The first condition is whether the species' population is markedly separated, or isolated, from other populations of the same taxon “as a consequence of physical, physiological, ecological, or behavioral factors.” When these four factors are evaluated, “[q]uantitative measures of genetic or morphological discontinuity may provide evidence of this separation.” The second condition, which does not apply here, is whether the population segment can be “delimited by international governmental boundaries within which differences in control of exploitation, management of habitat, conservation status, or regulatory mechanisms exist that are significant in light of section 4(a)(1)(D) of the Act.”

In determining the discreteness, or isolation, of the Mono Basin area sage grouse, one of the factors to consider is physical separation from the rest of the taxon. The petitioner did not provide substantial information to demonstrate that the Mono Basin area sage grouse are physically isolated from other nearby populations. Although these birds are associated with separate locations on a landscape consisting of various mountain ranges and intervening valleys, they are able to move between these areas. For example, sage grouse in Nevada are known to travel to lek sites in the Bodie Hills in California (Craig Mortimore, NDOW, pers. comm. 2002). Telemetry data from Nevada indicates that sage grouse move between the Desert Creek area and the Sweetwater Mountains (S. Stiver, pers. comm. 2002). Exchange is also possible between the northernmost lek locations in Lyon County and the next closest area of habitat to the north in the Pah Rah Range. The distance between these two locations (about 18 km (28 miles)) is well within the species' maximum estimated dispersal distance of 160 km (100 mi) (WDFW 1995; Schroeder et al. 1999).

The DPS policy states that genetic information may be used to provide evidence of separation. The petitioner cites an unpublished study which provides evidence to suggest that sage grouse in both Lyon County, Nevada, and Mono County, California, are genetically unique from the rest of the taxon (Benedict et al. 2000; Taylor 2000; Benedict et al. 2001). However, the results of this study are limited to genetic samples taken from the Bodie Hills and Long Valley areas in California, and the Desert Creek and Sweetwater areas in Nevada. These leks comprise approximately 31 percent of known lek areas in the Mono Basin area, and other leks that have not been located are probably present within the Mono Basin area. This study used samples from hunter-collected wings and, therefore, did not include lek areas closed to hunting. Given the limited genetic information available, a determination regarding separation of these genetically unique birds from the rest of the taxon cannot be completed. Benedict et al. (2000) recommends that additional studies be conducted, including morphology and behavioral studies, to clarify the taxonomy of the Mono Basin area sage grouse.

Two other factors to consider with regard to discreteness or isolation of a population are the behavioral and morphological aspects. Taylor (2002) initiated a study in 2001 to determine if previously collected genetic data relating to the Mono Basin area sage grouse are supported by behavioral and morphological differences. Male vocalizations, strutting behavior, and display rates were determined and compared for birds both within and outside the Mono Basin (Taylor 2002). Preliminary results from this work indicate that no behavioral differences exist between sage grouse within the Mono Basin and those found outside it (Taylor 2002). The comparative work on morphological characteristics has not been completed. Although this study is incomplete, it suggests that sage grouse within the Mono Basin cannot be considered a DPS on the basis of behavioral factors. The petitioner does not provide any information to document that sage grouse within the Mono Basin area exhibit any unique behavioral or morphological traits. No information is presented in the petition, nor is there any available in the Service files, to indicate that there are physical, genetic, behavioral, morphological, physiological, or ecological differences between sage grouse that occur in the Mono Basin and those found outside the area.

In summary, to make a DPS determination, we examined physical, physiological, ecological, and behavioral factors. Since there are no international government boundaries of significance, this condition for a finding of discreteness was not considered in reaching this determination. Neither the information presented in the petition nor that available in Service files presents substantial scientific or commercial information to demonstrate that the Mono Basin area sage grouse is discrete from the remainder of the taxon. Accordingly, we are unable to define a listable entity of sage grouse within the Mono Basin area. Therefore, we did not address the second element for determining a DPS, which is the potential significance of the Mono Basin area sage grouse to the remainder of the taxon. Finally, since the Mono Basin area sage grouse cannot be defined as a DPS at this time, we did not evaluate its status as endangered or threatened on the basis of the Act's definitions of those terms and the factors in section 4(a) of the Act.

The petitioner requests that we emergency-list the Mono Basin area sage grouse. Substantial information to define a listable entity in the Mono Basin area does not exist. However, in making this finding, we evaluated the threats to the Mono Basin area sage grouse presented by the petitioner to determine whether or not the continued survival of sage grouse in the Mono Basin area was threatened in a manner warranting emergency action. The Act identifies five factors to be considered, either singly or in combination, to determine whether a species may be threatened or endangered. The five listing factors that we must consider are: (1) Present or threatened destruction, modification, or curtailment of habitat or range; (2) overutilization for commercial, recreational, scientific, or educational purposes; (3) disease or predation; (4) inadequacy of existing regulatory mechanisms; and (5) other natural or human-caused factors affecting the species' continued existence. Our evaluation of these threats is presented below.

The petitioner cites multiple threats to sage grouse within the California portion of the Mono Basin area. These include large fires, cheatgrass invasion, pinyon-juniper invasion, high road densities, high-speed highways, powerlines, military installations, livestock grazing, livestock fencing, water diversions and groundwater pumping by the Los Angeles Department of Water and Power, joggers with off-leash dogs, dirt bikers, mountain bikers, sport-utility vehicle drivers, a recreational vehicle park, potential gold mining, the expansion of the Town of Mammoth Lakes airport, hunting, poaching, falconry, the landfill for the town of Mammoth Lakes, excessive soil erosion, a population bottleneck (the smallest number of individuals ever observed for a species) caused by winter conditions, demographic stochasticity, low sage grouse production, and improper grazing practices allowed by the Bureau of Land Management and the U.S. Forest Service. In the Nevada portion of the Mono Basin (Lyon County in particular was cited by the petitioner), the petitioner cites threats from agriculture, mining, traffic (related to both mining and highways), aircraft operations at an airstrip, development, grazing, and fire.

In reviewing the petition and available information, we find that most of the threats cited by the petitioner for the Mono Basin area are speculative, and that insufficient information is provided to demonstrate that they actually threaten the continued existence of sage grouse in the Mono Basin area. The petitioner cited threats such as high road densities and associated recreational road use by motorized recreational vehicle drivers, livestock fencing, a proposed recreational vehicle park, a proposed airport expansion for the town of Mammoth Lakes, and the Mammoth Lakes landfill. All potentially could threaten sage grouse populations in the area; however, none have been documented to do so. Hunting and a winter population bottleneck have been documented as threats for limited portions of the Mono Basin area (Gibson 1998, 2001) but have not been proven to threaten sage grouse populations for the Mono Basin area as a whole. A review of the best available scientific and commercial data does not lead us to conclude that the Mono Basin area sage grouse is threatened with extinction, nor are the threats of such a magnitude to warrant emergency listing.

Petition Finding

We have reviewed the petition, literature cited in the petition, other pertinent literature, and information available in Service files. After our review we find the petition does not present substantial information to indicate that the petitioned action is warranted. This finding is based on the following: (a) Insufficient information to determine whether the Mono Basin area sage grouse are separated from other sage grouse throughout the range of the taxon; (b) contradictory information presented by preliminary results from a behavioral and morphological study that suggests that Mono Basin area sage grouse are not different from other populations of greater sage grouse; and (c) insufficient information to document that the threats presented threaten the continued existence of the species in the Mono Basin.

References Cited

A complete list of all references cited herein is available upon request from the Nevada Fish and Wildlife Office (see ADDRESSES).

Author

The primary author of this notice is Kevin Kritz, U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office (see ADDRESSES).

Authority

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

Dated: December 10, 2002.

Steve Williams,

Director, Fish and Wildlife Service.