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SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; 90-day Finding for Petitions To List the Greater Sage-grouse as Threatened or Endangered
DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 90day finding for three petitions to list the greater sagegrouse (Centrocercus urophasianus) as threatened or endangered, under the Endangered Species Act of 1973, as amended. We find that these petitions and additional information available in our files present substantial information indicating that listing the greater sagegrouse may be warranted. As a result of this finding, we are initiating a status review. We ask the public to submit to us any pertinent information concerning the status of or threats to this species.
SUMMARY: Findings on petitions, etc.—; Greater sage-grouse,
Section 4(b)(3)(A) of the Endangered Species Act of 1973, as amended
(Act) (16 U.S.C. 1531 et seq.), requires that we make a finding on whether a
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petition to list, delist, or reclassify a species presents substantial
scientific or commercial information to indicate that the petitioned
action may be warranted. We are to base this finding on all information
available to us at the time we make the finding. To the maximum extent
practicable, we must make this finding within 90 days of receiving the
petition and publish a notice of the finding promptly in the Federal
Register. Our standard for substantial information 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 424.14(b)). When a substantial finding is
made, we are required to promptly begin a review of the status of the species, if one has not already been initiated.
On July 2, 2002, we received a petition from Craig C. Dremann to list the greater sagegrouse (Centrocercus urophasianus) as endangered across its entire range. Mr. Dremann's 7page petition summarizes several threats to the species' habitat, based on the author's review of the Oregon Bureau of Land Management's (BLM) management guidelines for the greater sagegrouse (Barett et al. 2000). A second petition requesting the same action was received from the Institute for Wildlife Protection on March 24, 2003 (cited as Webb 2002). On December 29, 2003, we received a third petition from the American Lands Alliance and 20 additional conservation organizations (American Lands Alliance et al.) to list the greater sagegrouse as threatened or endangered rangewide. Both of these petitions describe multiple threats to the greater sagegrouse from habitat loss and degradation, overutilization, disease and predation, the lack of regulatory protection, humanrelated factors (e.g., pesticide use), and natural events (e.g., drought). They also provide an extensive discussion, citing scientific literature, of how the unique biological characteristics of the greater sagegrouse compound extrinsic threats affecting the species' habitat and genetic stability. These petitions are 553 and 218 pages, with an additional 459 and 306 pages of literature cited, respectively. Because the petitions submitted by the Institute for Wildlife Protection and American Lands Alliance et al. were received after Mr. Dremann's petition, we consider those as providing supporting information for the original request.
In addition to reviewing the three petitions, we have reviewed other pertinent information and scientific literature available in our files, as well as other information that has been provided to us, including detailed comments on the petitions (particularly on the American Lands Alliance et al. petition) submitted by the Petroleum Association of Wyoming (PAW).
In addition to the petitions discussed above, we have previously addressed a number of other petitions related to subspecies and Distinct Population Segments (DPSs) of the greater sagegrouse. In a 90day finding on a petition submitted by the Institute for Wildlife Protection to list the western subspecies of the greater sagegrouse (C.u. phaios) as threatened or endangered (February 7, 2003; 68 FR 6500), we concluded there was no scientific basis to recognize the eastern or western subspecies designations. Thus, we determined that the petition did not present substantial scientific or commercial information indicating that listing the western subspecies was warranted. For the same reason, on January 7, 2004, we published a negative 90day finding for a subsequent petition from the same organization requesting that we list the eastern subspecies of the greater sagegrouse (C.u. urophasianus) (69 FR 933).
On May 7, 2001, we published a 12month petition finding which determined that listing the Columbia Basin DPS of the western sage grouse (now considered the greater sagegrouse) was warranted but precluded by higher priority listing actions (66 FR 22984). The Columbia Basin DPS of the greater sagegrouse is currently a candidate for listing (67 FR 40657). In a 90day finding published December 26, 2002 (67 FR 78811), we determined that a petition to emergency list the Mono Basin population of the greater sagegrouse did not present substantial information, because the petitioner failed to adequately identify the DPS or provide sufficient information to document that continued existence of the species was threatened in the Mono Basin of California and Nevada.
A closely related species, the Gunnison sagegrouse (C. minimus), is currently on our candidate list (67 FR 40657). Because it is a separate species (Young et al. 2000), the Gunnison sagegrouse is not included in this finding.
We find the petitions by Craig C. Dremann, the Institute for Wildlife and the American Lands Alliance present substantial information indicating that listing the greater sagegrouse may be warranted. In making this finding we rely on information provided by the petitioners and evaluate that information in accordance with 50 CFR 424.14(b). The contents of this finding summarize that information included in the petition and which was available to us at the time of the petition review. Our review for the purposes of a socalled ``90 day'' finding under section 4(b)(3)(A) of the Act and section 424.14(b) of our regulations is limited to a determination of whether the information in the petition meets the ``substantial information'' threshold. We do not conduct additional research at this point, nor do we subject the petition to rigorous critical review. Rather, as the Act and regulations contemplate, at the 90day finding, we accept the petitioner's sources and characterizations of the information unless we have specific information to the contrary. Our finding is that the petition states a reasonable case for listing on its face. Thus, in this finding, we express no view as to the ultimate issue of whether the species should be listed. We can come to a conclusion on that issue only after a more thorough review of the species' status. In that review, which will take approximately nine more months, we will perform a rigorous critical analysis of the best available scientific information, not just the information in the petition. We will ensure that the data used to make our determination as to the status of the species is consistent with the Endangered Species Act and the Information Quality Act. We ask the public to submit to us any pertinent information concerning the status of or threats to this species.
The following information regarding the description and natural history of the greater sagegrouse (sagegrouse) (American
Ornithologists' Union (AOU) 2000) has been condensed from these
sources: Aldrich 1963; Johnsgard 1973; Connelly et al. 1988; Connelly
et al. 2000; Fischer et al. 1993; Drut 1994; Western States Sage and
Columbia SharpTailed Grouse Technical Committee (WSSCSTGTC) 1996 and
1998; and Schroeder et al. 1999. Specific references are cited for data of particular relevance to this finding.
The sagegrouse is the largest North American grouse species. Adult
males range in length 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 length 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
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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.
Sagegrouse depend on a variety of shrubsteppe habitats throughout their life cycle, and are particularly tied to several species of sagebrush (Wyoming big sagebrush (Artemisia tridentata wyomingensis), mountain big sagebrush (A. t. vaseyana), and basin big sagebrush (A. t. tridentata)). Other sagebrush species, such as low sagebrush (A. arbuscula), black sagebrush (A. nova), fringed sagebrush (A. frigida) and silver sagebrush (A. cana) are also used. Throughout much of the year, adult sagegrouse 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 shrubsteppe plant communities affect habitat use by sagegrouse populations (Connelly et al. 2000; Johnsgard 2002). However, these populations also exhibit strong site fidelity (loyalty to a particular area). Sagegrouse may disperse up to 160 kilometers (km) (100 miles (mi)) between seasonal use areas; however, average individual movements are generally less than 34 km (21 mi) (Schroeder et al. 1999). Sagegrouse also are capable of dispersing over areas of unsuitable habitat (Connelly et al. 1988). Because of the dependence of sagegrouse on sagebrush, they are rarely found outside of this habitat type (typically limited to periods of migration).
Sagegrouse consume a wide variety of forb (any herbaceous plant that is not a grass) species from spring to early fall (Schroeder et al. 1999). Hens require an abundance of forbs for prelaying and nesting periods. An assortment of forb and insect species form important nutritional components for chicks during the early stages of development. Sagegrouse typically seek out more mesic (moist) habitats that provide greater amounts of succulent forbs and insects during the summer and early fall (Schroeder et al. 1999). Winter habitat use varies based upon snow accumulations and elevation gradients (Connelly et al. 2000). Sagebrush constitutes 100 percent of the sagegrouse winter diet as it is typically the only food resource available. Differences in the species of sagebrush consumed in the winter may be tied to availability, as well as preference for greater protein levels and lower levels of volatile oils (Connelly et al. 2000).
During the spring breeding season, primarily during the morning hours just after dawn, male sagegrouse gather together and perform courtship displays on display areas called leks. Areas of bare soil, shortgrass steppe, windswept ridges, exposed knolls, or other relatively open sites may serve as leks. Leks are often surrounded by denser shrubsteppe cover. Leks can be formed opportunistically at sites within or adjacent to nesting habitat (Connelly et al. 2000), and therefore are not a limiting factor for sagegrouse. They range in size from less than 0.4 hectare (ha) (1 acre (ac)) to over 40 ha (100 ac) and can host from 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. 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. A relatively small number of dominant males accounts for the majority of breeding on a given lek (Schroeder et al. 1999).
Females may travel more than 20 km (12.5 mi) after mating (Connelly et al. 2000). They typically select nest sites under sagebrush cover, although other shrub or bunchgrass species are sometimes used. Nests are relatively simple, consisting of scrapes on the ground that are sometimes lined with feathers and vegetation. Clutch size ranges from 6 to 13 eggs. Nest success ranges from 12 to 86 percent and is relatively low compared to other prairie grouse species (Connelly et al. 2000). Shrub canopy and grass cover provide concealment for sagegrouse nests and young, and are critical for reproductive success. Chicks begin to fly at 2 to 3 weeks of age, and broods remain together for up to 12 weeks. Most juvenile mortality occurs during nesting and the chicks' flightless stage, and is due primarily to predation or severe weather conditions (Schroeder et al. 1999; Schroeder and Baydack 2001).
Sagegrouse typically live between 1 and 4 years, but sagegrouse up to 10 years of age have been recorded in the wild. The annual mortality rate for sagegrouse is roughly 50 to 55 percent, which is relatively low compared to other prairie grouse species. Females generally have a higher survival rate than males, which accounts for a femalebiased sex ratio in adult birds.
Prior to European expansion into western North America, sagegrouse were believed to occur in 16 States and 3 Canadian provinces Washington, Oregon, California, Nevada, Idaho, Montana, Wyoming, Colorado, Utah, South Dakota, North Dakota, Nebraska, Kansas, Oklahoma, New Mexico, Arizona, British Columbia, Alberta, and Saskatchewan (Schroeder et al. 1999; Young et al. 2000). The distribution of sage grouse has contracted in a number of areas, most notably along the northern and northwestern periphery and in the center of their historic range. At present, sagegrouse 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. Sagegrouse have been extirpated from Nebraska, Kansas, Oklahoma, New Mexico, Arizona, and British Columbia (Schroeder et al. 1999; Young et al. 2000). The vast majority of the current distribution of the greater sagegrouse is within the United States.
In a Federal Register notice dated August 24, 2000, we stated that, prior to European expansion across the continent, there may have been between 1.6 and 16 million sagegrouse in western North America (65 FR 51578). These estimates were calculated by multiplying sagegrouse density estimates for a range of habitats considered of low to high quality (assuming 1 grouse per 1 square kilometer (km\2\) (0.4 square mile (mi\2\)) as an approximate lower density limit, and 10 grouse per km\2\ (0.4 mi\2\) as an approximate upper density limit (Michael Schroeder, Washington Department of Fish and Wildlife, pers. comm. 1999, cited in 65 FR 51578)) by the most recent estimate of historic sage grouse distribution (1.6 million km\2\ (0.64 million mi\2\).
The WSSCSTGTC (1999) estimated that there may have been 1.1 million birds in 1800. Braun (1998) estimated that the 1998 rangewide spring population numbered about 157,000 sagegrouse, while we estimated the rangewide population of sagegrouse at roughly between 100,000 and 500,000 birds in 2000 (65 FR 51578; August 24, 2000). Using our population estimates in the August 24, 2000, Federal Register notice, sagegrouse population numbers may have declined between 69 and 99 percent from historic to recent times (65 FR 51578). The WSSCSTGTC (1999) estimated the decline between historic and present day to have been about 86 percent.
Apparently, much of the overall decline in sagegrouse abundance
occurred from the late 1800s to the mid1900s (Hornaday 1916; Crawford 1982; Drut 1994; Washington Department of
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Fish and Wildlife 1995; Braun 1998; Schroeder et al. 1999). Other
declines in sagegrouse populations apparently occurred in the 1920s
and 1930s, and then again in the 1960s and 1970s (Connelly and Braun
1997). Sagegrouse populations in Colorado have declined from 45 to 82
percent since 1980. Populations in Wyoming and Washington have declined
17 and 47 percent, respectively, from pre1985 to post1985 (Braun
1998). Sagegrouse numbers in South Dakota declined from approximately
25,000 birds in the 1950's to 5,000 in 1992 (Drut 1994). In Utah, the
decline is estimated at 50 percent since settlement (Drut 1994). The
State of Nevada has reported declining sagegrouse populations since
1970 (Neel 2001). The aforementioned population trends are based on lek
counts. Braun (1998) reports that the number of males per lek, an
indicator of population trend, has continuously declined across the species' range since the early 1950s.
In 1946, Aldrich described a subspecies of greater sagegrouse in the northwestern portion of the species' range based on slight color differences in the plumage of 11 museum specimens. In 1957, the AOU recognized a subspecies division within the sagegrouse taxon. However, since that time it has not conducted a review of this subspecies distinction. The AOU stopped listing subspecies as of the 6th (1983) edition of its Checklist, although it recommended the continued use of the 5th edition for taxonomy at the subspecific level. The AOU has not formally or officially reviewed the subspecific treatment of most North American birds, although it is working toward that goal (Richard C. Banks, National Museum of Natural History, pers. comm. with Oregon Field Office of the Service 2000, 2002). Therefore, the western and eastern subspecies of sage grouse are still recognized by the AOU, based on its 1957 consideration of the taxon.
The validity of the taxonomic separation has been questioned (Johnsgard 1983; Johnsgard 2002; Benedict et al. 2003). In our 90day petition findings for the western subspecies of the greater sagegrouse (68 FR 6500; February 7, 2003) and eastern subspecies of the greater sagegrouse (69 FR 933; January 7, 2004), we concluded there was no basis to recognize these subspecies due to the lack of distinct genetic differences between the two, the lack of ecological or physical factors that might indicate differentiation between the populations, and evidence that birds freely cross the supposed boundary between the subspecies. We continue to believe that our earlier conclusion regarding lack of subspecies differences is correct.
Pursuant to section 4(a) of the Act, we may list a species, subspecies, or DPS of vertebrate taxa on the basis of any of the following five factors(A) destruction, modification, or curtailment of habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) inadequacy of existing regulatory mechanisms; and (E) other manmade or natural factors affecting its continued existence. The rangewide petition submitted by Mr. Dremann asserts that greater sagegrouse are subject to threats under Factor A. The other petitions assert that greater sagegrouse are subject to threats under all listing factors, but primarily under Factor A. We used information provided by the petitioners and available in our files to address these factors as follows.
Under Factor A, the petitioners assert that greater sagegrouse have been impacted by the permanent conversion of sagebrush habitats to agricultural lands, and provide both rangewide and sitespecific examples which have been published in the scientific literature.
Sagebrush once covered roughly 63 million ha (156 million ac) in western North America (West 1996; Miller and Eddleman 2001, cited in Knick et al. 2003). In our review of the scientific literature, we found that western rangelands were converted to agricultural lands on a large scale under the series of Homestead Acts in the 1800s (Braun 1998). According to Schroeder et al. (1999), millions of hectares of native sagebrush habitat have been cultivated for the production of potatoes, wheat, and other crops. In some States, more than 70 percent of sagebrush shrubsteppe habitats have been converted to agricultural crops (Braun 1998). This impact has been especially apparent in the Columbia Basin of the Northwest and the Snake River Plain of Idaho. Dobler (1994) estimated that approximately 60 percent of the original shrubsteppe habitat in Washington has been converted to primarily agricultural uses. Hironaka et al. (1983, cited in Knick et al. 2003) estimated that 99 percent of basin big sagebrush (A. t. tridentata) habitat in the Snake River Plain has been converted to cropland.
Development of irrigation projects to support agricultural production also has resulted in additional sagegrouse habitat loss (Braun 1998). During the mid1900s, a number of hydroelectric dams were developed on the Columbia and Snake Rivers in Washington and Oregon. More than 400 dams were constructed on the Columbia River system alone. The irrigation projects formed by these reservoirs converted native shrubsteppe habitat to irrigated croplands adjacent to the rivers. The projects precipitated conversion of large expanses of upland shrub steppe habitat in the Columbia Basin for irrigated agriculture (August 24, 2000; 65 FR 51578). This conversion has resulted in the loss of 60 percent of the original 10.4 millon acres of shrubsteppe habitats present prior to European settlement in this area (Dobler 1994). The creation of these reservoirs also inundated hundreds of kilometers of riparian habitats used by sagegrouse broods (Braun 1998). Shrubsteppe habitat continues to be converted for both dryland and irrigated crop production, albeit at muchreduced levels (65 FR 51578; Braun 1998). However, the Bureau of Reclamation retains options for further development of the Columbia Basin Irrigation Project in central Washington (65 FR 51578).
All three petitions identified sagebrush conversion resulting from both chemical (herbicide) and mechanical treatments (shredding, roller chopping, hand slashing, bulldozing, beating, chaining, root plowing, and disk plowing) as a negative impact to greater sagegrouse habitat. The petitions quantify some of this conversion and discuss the resulting impacts to greater sagegrouse populations based on information provided in the scientific literature. Webb (2002) and American Lands Alliance et al. also extensively explore the cumulative effects on the greater sagegrouse resulting from habitat conversion using these methods.
Large expanses of sagebrush have been removed and reseeded with nonnative grasses to increase forage production (Shane et al. 1983, cited in Knick et al. 2003). In addition, thinning to reduce sagebrush density has long been practiced and continues today (Wamboldt et al. 2002, cited in Knick et al. 2003). Braun (1998) concludes that since European settlement of western North America, no sagebrush habitats used by greater sagegrouse have escaped these types of treatments.
Mechanical treatments, if carefully designed and executed, can be
beneficial to sagegrouse by improving herbaceous cover, forb
production, and resprouting of sagebrush (Braun 1998). However, adverse
effects also have been documented (Connelly et al. 2000). In Montana, the number of breeding males
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declined by 73 percent after 16 percent of the habitat was plowed
(Connelly et al. 2000). Mechanical treatments in blocks greater than
100 ha (247 ac), or of any size reseeded with exotic grasses, degrade
sagegrouse habitat by altering the structure and composition of the
vegetative community (Braun 1998). Connelly et al. (2000) recommend
managing for 1525 percent of sagebrush canopy cover to maintain
breeding habitat. Removal of greater than 40 percent of breeding habitat can result in the loss of the breeding population.
Greater sagegrouse response to herbicide treatments depends on the extent to which forbs and sagebrush are killed. Chemical control of sagebrush has resulted in major declines of sagegrouse breeding populations through the loss of live sagebrush cover (Connelly et al. 2000). Herbicide treatment also can result in sagegrouse emigration from affected areas (Connelly et al. 2000), and has been documented to reduce the brood carrying capacity of an area in Idaho (Klebenow 1970). While the total size of herbicidetreated areas is unknown, Braun (1998) estimates it exceeds 20 to 25 percent of the remaining sagebrushdominated rangelands. Small treatments interspersed with nontreated sagebrush habitats appear to be neutral in their effects on sagegrouse. However, all large block treatments greater than 200 ha (494 ac) negatively affect sagegrouse (Braun 1998). Schroeder et al. (1999) and Braun (1998) estimated that millions of hectares within current sagegrouse habitat have been treated both mechanically and chemically to remove sagebrush since the early 1960s.
The petitions from the Institute for Wildlife Protection and American Lands Alliance et al. identify loss of habitat from mining as a significant impact to the greater sagegrouse. In addition to the direct loss of habitat resulting from strip mining, these petitions cite scientific literature regarding the difficulty of reestablishing sagebrush (Lovich and Bainbridge 1999, Saab and Rich 1997, and Rotenberry 1998, as cited in Webb 2002).
Development of mines and energy resources within the distribution of the sagegrouse began prior to 1900 (Robbins and Ward 1994, cited in Braun 1998). Coal, gold, and uranium mining has impacted sagegrouse habitats throughout the West (Braun 1998). Immediate impacts to the greater sagegrouse associated with mining include direct habitat loss from mining, especially open pit mining, and construction of associated facilities, roads, and powerlines (Braun 1998; Connelly et al. 2000). For example in Wyoming and Montana there is an estimated 38,833 ha (96,000 acres) of disturbed federal and nonfederal surface associated with existing coal mining operations. Over the next ten years, approximately 20,243 ha (50,000 acres) are estimated to be disturbed for coal mining activities. Of that, 14,170 ha (35,000 acres) should be reclaimed within the same timeperiod, resulting in a net annual disturbance of 607 ha (1,500 acres) (Kermit Witherbee, Bureau of Land Management, pers. commun.). However, longterm functional habitat recovery would require an extended period of time (Bureau of Land Management 2003), and population reestablishment may require at least 20 to 30 years (Braun 1998). Sagegrouse have been documented to return to some reclaimed mining areas, but there is no evidence that population levels attain their previous size (Braun 1998).
Proposed coalbed methane development in the Powder River Basin of Wyoming is expected to result in the loss of 21,711 ha (53,626 ac) of sagebrush shrublands by 2011 (Bureau of Land Management 2003). Current sagegrouse habitat loss in the basin from coalbed methane is estimated at 2,024 (5,000 ac) (Braun et al. 2002). Although reclamation of shortterm disturbances will be concurrent with project development, ``sagegrouse habitats would not be restored to predisturbance conditions for an extended period because of the time need to develop sagebrush stands with characteristics that are preferred by sage grouse.'' (Bureau of Land Management 2003a). Disturbance to other sage grouse habitats, such as late summer/broodrearing areas, was not quantified in the Final Environmental Impact Statement for this project, but ``disturbance would occur to all other habitat types, including nesting, brood rearing, and wintering areas that are located more than 0.25 miles from lek sites'' (Bureau of Land Management 2003a). The Bureau has proposed avoiding leks during the breeding season, minimizing noise from compressors, and locating powerlines 0.5 mi from breeding and nesting areas (Bureau of Land Management 2003a). Within the entire Powder River Basin, over 80 percent of the surface ownership where coalbed methane development is occurring is private, where mitigation is not required (Braun et al. 2002).
All petitioners identified urban/suburban development as negatively impacting greater sagegrouse habitats. They support their concerns by identifying documented habitat losses from urban development in several states (Braun 1998 and Brigham 1995, as cited in Webb 2002), as well as information presented in the Gunnison sagegrouse management plans. The petitioners also discuss interrelated effects of urban/suburban development, such as construction of necessary infrastructure (roads, powerlines, and pipelines) and predation threats from the introduction of domestic pets.
Historic destruction of sagegrouse habitats for urban development undoubtedly occurred (Braun 1998). More recent urban expansion into rural subdivisions is also resulting in both direct habitat loss and conversion, as well as avoidance of suitable habitats by sagegrouse around these areas due to the presence of humans and pets (Braun 1998; Connelly et al. 2000). In some Colorado counties, up to 50 percent of sagegrouse habitat is under rural subdivision development, and it is estimated that 3 to 5 percent of all sagegrouse historic habitat in Colorado has been developed into urban areas (Braun 1998). We are unaware of similar estimates for other States within the range of the greater sagegrouse.
In addition to habitat loss from conversion to agriculture, chemical and mechanical treatments, mining development, and urban/ suburban development, sagebrush habitat losses also are occurring as a result of the apparent interaction of natural and anthropogenic factors. According to an article in the Autumn 2003 issue of Utah Division of Wildlife Resource's ``Wildlife Review,'' upwards of 400,000 acres (162,000 ha) of dead or dying Wyoming big sagebrush had been documented by State biologists by the end of June 2003 (Fairchild 2003). The species of sagebrush affected provides important food and cover to sagebrush obligate species, including greater sagegrouse. Reasons for the dieoff are not entirely clear, but appear to be related to drought, fire suppression, and livestock and big game grazing.
All petitioners identify livestock grazing as one of the primary
factors that has degraded greater sagegrouse habitats. The petitions
discuss not only the direct impacts of livestock grazing on forage
removal and sagebrush trampling (Patterson 1957, Yocom 1956, Dobkin
1995, Autenrieth et al. 1997, Klebenow 1982, Braun 1998, and Braun
2001, as cited in Webb 2002), but they also provide extensive reviews
of associated factors, such as habitat degradation from livestock
concentrations around water developments (Thomas et al. 1979 and Braun
1998, as cited in Webb 2002), habitat fragmentation from fences (Call [[Page 21489]]
and Maser 1985, Braun 1998 and Wilkinson 2001, as cited in Webb 2002),
rangeland treatments to increase forage (Drut 1994, Rogers 1965,
Klebenow 1970, Martin 1970, Pyrah 1970, 1971, Wallestad 1971, 1975 and
Braun et al. 1977, as cited in Webb 2002), invasion of exotic
vegetative species (Hoffman 1991, Drut 1994 and Fleischner 1994, as
cited in Webb 2002), and changes in soil characteristics, particularly
the soil crust (Mack and Thompson 1982 and Quigley and Arbelbide 1997,
as cited in Dremann 2002; St. Clair et al. 1993, as cited in Webb 2002).
Due to the absence of habitat overlap, it is unlikely that sage grouse evolved with intensive grazing by wild herbivores, such as bison (Connelly et al. 2000). While little experimental evidence directly links grazing management to sagegrouse population trends (Braun 1998), the reduction of grass heights in nesting and broodrearing areas negatively affects nesting success by reducing cover necessary for predator avoidance (Gregg et al. 1994; DeLong et al. 1995; Connelly et al. 2000). In addition, livestock consumption of forbs may reduce food availability for sagegrouse (see discussion under Factor E). This is particularly important for prelaying hens, as forbs provide calcium, phosphorus, and protein. A hen's nutritional condition affects nest initiation rate, clutch size, and subsequent reproductive success (Connelly et al. 2000). Livestock grazing also may result in trampling mortality of seedling sagebrush (Connelly et al. 2000). This information suggests that grazing by livestock could reduce breeding habitat, subsequently affecting sagegrouse populations negatively (Beck and Mitchell 2000). However, additional replication studies are necessary to determine the effect of grazing management on sagegrouse nesting success (Beck and Mitchell 2000). Exclosure studies have demonstrated that domestic livestock grazing also reduces water infiltration rates and cover of herbaceous plants and litter, as well as compacting soils and increasing soil erosion (Braun 1998). This results in a change in proportion of shrub, grass, and forbs components in the affected area, and an increased invasion of exotic vegetative species that do not provide suitable habitat for sagegrouse (Miller and Eddleman 2000). Development of springs and other water sources to support livestock in upland shrubsteppe habitats can artificially concentrate domestic and wild ungulates in important sagegrouse habitats, thereby exacerbating grazing impacts in those areas.
Excessive grazing by wild horses has been identified by all petitioners as contributing to a decline in sagegrouse habitat. We are unaware of any studies that specifically address the impact of wild horses on sagebrush and sagegrouse. However, we believe that some impacts from wild horse grazing may be similar to the nature of impacts from domestic livestock in sagebrush habitats.
Fire often has been used as a management tool to reduce sagebrush canopy cover (Connelly et al. 2000) for many reasons, including increasing forage for the benefit of domestic livestock and wild ungulates. Our knowledge of sagegrouse response to fire is imperfect, but current information indicates that the species' response to fire varies depending on a variety of factors. Some studies suggest fire increases forbs and other foods important to sagegrouse (Braun 1998); others show food resources do not change between burned and unburned areas (Connelly et al. 2000), but that sagegrouse populations decline in response to loss of habitat (Connelly et al. 2000). A clear positive response of greater sagegrouse to fire has not been demonstrated (Braun 1998). Several subspecies of ``big'' sagebrush (Artemisia tridentata tridentata, A.t. vaseyana, and A.t. wyomingensis), which provide important sagegrouse habitat, are killed by fire and do not resprout after burning (Wrobleski and Kauffman 2003). This suggests that these sagebrush subspecies evolved in an environment where wildfire was infrequent (interval of 30 to 50 years) and patchy in distribution (Braun 1998). Therefore, frequent prescribed fires in these habitats may be detrimental to sagegrouse. The effect of fire on greater sagegrouse habitats in montane sagebrush communities is not clear (Connelly et al. 2000). Conversely, long fire intervals and fire suppression can result in increased dominance of woody species, such as western juniper (Juniperus occidentalis) (Wrobleski and Kauffman 2003), resulting in a near total loss of shrubs and sagegrouse habitat (Miller and Eddleman 2000).
Wildfires have destroyed extensive areas of sagebrush habitat in recent years. For example, 30 to 40 percent of the sagegrouse habitat in southern Idaho was lost in a 5year period (19972001) due to range fires, according to S. SatherBlair, a wildlife biologist for the BLM in Idaho (quoted in Healy 2001). The largest contiguous patch of sagebrush habitat in southern Idaho occupies approximately 700,000 acres, according to M. Pellant, a rangeland ecologist with the Idaho BLM (quoted in Healy 2001). Of that total area, about 500,000 acres burned in the years 19992001; half of the acres that burned had already been affected by previous fires. In Nevada in 2000, more than 660,000 acres burned statewide (NDOW Hunting Area and Unit 2000 Fire Report). Many of the fires burned in habitat that was in fairly good condition, and which supported good numbers of sagegrouse (NDOW Hunting Area and Unit 2000 Fire Report).
Frequent fires with short intervals within sagebrush habitats favor invasion of cheatgrass (Bromus tectrorum), an exotic species that is unsuitable as sagegrouse habitat (Schroeder et al. 1999). Large areas of habitat in the western distribution of the greater sagegrouse have already been converted to cheatgrass (Connelly et al. 2000). Recovery of an area to sagebrush after cheatgrass becomes established is extremely difficult. The loss of habitat due to cheatgrass establishment results in the loss of sagegrouse populations (Connelly et al. 2000). Conversion to cheatgrass also reduces wildfire intervals in sagebrush ecosystems from 30 to 5 years (Pellant 1996). These shortened fire intervals further exacerbate the effects of fire in remaining sagegrouse habitats. Conversion of sagebrush vegetation communities to exotic species, such as Russian thistle (Salsola spp.), halogeton (Halogeton glomeratus), and medusahead (Taeniatherum asperum), also has resulted in sagegrouse habitat loss (Miller and Eddleman 2000).
Petitions from the Institute for Wildlife Protection and American Lands Alliance et al. assert that military activities negatively affect sagegrouse habitats. These petitions primarily refer to documented negative effects to sagegrouse from activities on the Yakima Training Center in eastern Washington, as well as providing general information regarding impacts of track vehicles on vegetation and soils.
Military facilities are found throughout the range of the greater
sagegrouse. The impact of military activities at these facilities on
local sagegrouse populations vary from direct mortality to habitat
degradation and loss. In the fall of 1995, the U.S. Army conducted its
first largescale training exercise at the 800 square km (313 square
mi) Yakima Training Center in Washington State. Analysis of the impacts
from this exercise indicated that over 9 percent of the sagebrush
plants within sagegrouse protection areas experienced major structural
damage (Cadwell et al. 1996). In addition, modeling exercises [[Page 21490]]
indicated that sagebrush cover would decline due to similar training
scenarios if conducted on a biannual basis (Cadwell et al. 1996).
Military training activities provide multiple ignition sources, thereby
increasing the potential for fire within suitable sagegrouse habitat
at military facilities. In 1996, over 25,000 ha (60,000 ac) of shrub
steppe habitat was burned as a result of training activities at the
Yakima Training Center (65 FR 51578), and other large range fires have
occurred at the installation since. The Yakima Training Center has
developed a management plan for sagegrouse habitat on the facility (65
FR 51578). While military operations may significantly affect local
sagegrouse populations, particularly where populations are isolated,
there are few facilities that overlap suitable sagegrouse habitats. We
could find no scientific information to support the petitioners'
contention that military operations are a limiting factor on the greater sagegrouse populations rangewide.
The petitions from the Institute for Wildlife Protection and American Lands Alliance et al. assert that habitat fragmentation from mining and energy development, including windpower, negatively impacts the greater sagegrouse. In addition to the direct habitat loss previously mentioned, associated facilities, roads, and powerlines, as well as noise and increased human activities (see discussion under Factor E) associated with mining and energy development, can fragment sagegrouse habitats (Braun 1998; Connelly et al. 2000). More chronic impacts are less clear. Lek abandonment as a result of oil and gas development has been observed in Alberta (Connelly et al. 2000), and, in the Powder River Basin of Wyoming, leks within 0.4 km (0.25 mi) of a coalbed methane well have significantly fewer males compared to less disturbed leks (Braun et al. 2002). The network of roads, trails, and powerlines associated with wells and compressor stations decreases the suitability and availability of sagegrouse habitat, and fragments remaining habitats (Aldridge and Brigham 2003). Human activities along these corridors can disrupt breeding activities and negatively affect survival (Aldridge and Brigham 2003). Female sagegrouse captured on leks near oil and gas development in Wyoming had lower nestinitiation rates, longer movements to nest sites, and different nesting habitats than hens captured on undisturbed sites (Lyon 2000; Lyon and Anderson 2003). Lower nestinitiation rates can result in lower sagegrouse productivity in these areas (Lyon and Anderson 2003). Activities which remove live sagebrush and reduce patch size negatively affect all sagebrush obligates (Braun et al. 2002).
In our review of available information, we found that sagegrouse habitats also are fragmented by fences, powerlines, roads, and other facilities associated with grazing, energy development, urban/suburban development, recreation, and the general development of western rangelands. Fences, powerlines and roads also are a direct mortality source for the greater sagegrouse (see discussion under Factor E).
Fences constructed for property boundary delineation and livestock management provide perching locations for raptors and travel corridors for mammalian predators, thereby increasing greater sagegrouse predation (Braun 1998; Connelly et al. 2000). Greater sagegrouse avoidance of habitat adjacent to fences, presumably to minimize the risk of predation, effectively results in habitat fragmentation even if the actual habitat is not removed (Braun 1998). Over 51,000 km (31,690 mi) of fences were constructed on BLM lands supporting sagegrouse populations between 1962 and 1997 (Connelly et al. 2000). Fences also provide a collision hazard, resulting in injury and death (Call and Maser 1985).
As with fences, powerlines provide perches for raptors (Connelly et al. 2000; Vander Haegen et al. 2002, cited in Knick et al. 2003), thereby resulting in sagegrouse avoidance of powerline corridors (Braun 1998). Approximately 9,656 km (6,000 mi) of powerlines have been constructed in sagegrouse habitat to support coalbed methane production in Wyoming's Powder River Basin within the past few years. Leks within 0.4 km (0.25 mi) of those lines have significantly lower growth rates than leks further from these lines, presumably as the result of increased raptor predation (Braun et al. 2002). The presence of powerlines also contributes to habitat fragmentation, as greater sagegrouse typically will not use areas immediately adjacent to powerlines, even if habitat is suitable (Braun 1998).
Roads result in habitat loss and fragmentation, although the amount of habitat lost is unknown (Braun 1998). Roads also provide corridors for invasion of exotic vegetative species and predators. Lyon (2000) found that successful sagegrouse hens nested farther (mean distance = 1,138 m) from the nearest road than did unsuccessful hens (mean distance = 268 m) on Pinedale Mesa near Pinedale, Wyoming.
In summary, sagebrush once covered approximately 63 million ha (156 million ac) in western North America. Almost none of the remaining habitats are unaltered (Braun 1998; Knick et al. 2003). Approximately onehalf of the original area occupied by sagegrouse is no longer capable of supporting sagegrouse on a yearround basis (Braun 1998). Habitat alteration, through loss and degradation, has been identified as the primary explanation for the rangewide reduction in the distribution and population size of the greater sagegrouse (Schroeder et al. 1999).
Based on the foregoing discussion, we believe that substantial information is available indicating that previous and ongoing habitat loss, degradation, and fragmentation within the remaining habitats are factors that may threaten the continued existence of the greater sage grouse.
Under Factor B, the Institute for Wildlife Protection and American Lands Alliance et al. cite hunting as a threat to the greater sage grouse in the contiguous United States. The petitions discuss historic losses of sagegrouse from overhunting, synergistic effects of hunting and habitat degradation, hunting as additive mortality, losses from poaching and incidental take, failure of the States to quantify hunting mortality from falconry seasons, the influence of hunting on extinction risks for small populations, and the effects of nonconsumptive activities (bird watching).
In the early 1900s, Hornaday (1916) cautioned that sagegrouse and other grouse species would face extinction if hunting practices were not changed. Sagegrouse hunting at that time was unregulated and market hunting, poaching, and overharvesting reduced historic sage grouse populations (Hornaday 1916; Girard 1937; Schroeder et al. 1999). The historical impacts of hunting on the greater sagegrouse may have been exacerbated by impacts from human expansion into sagebrushsteppe habitats (Girard 1937).
Greater sagegrouse are currently hunted in 10 of the 11 States
where they occur (Bohne in litt. 2003) and hunting is regulated by
State wildlife agencies. Most State agencies base their hunting
regulations on local population information and peerreviewed
scientific literature regarding the impacts of hunting on greater sage
grouse (Bohne in litt. 2003). Hunting seasons are reviewed annually,
and most States implement adaptive harvest management based on harvest
and population data. Hunting may be an additive mortality if brood hens and young birds sustain the highest hunting
[[Page 21491]]
mortality within a population (Braun 1998; Johnson and Braun 1999).
Hunting seasons that are managed to evenly distribute mortality across
all age and sex classes are less likely to negatively affect subsequent
breeding populations (Braun 1998). Except for Montana, all States with
hunting seasons have changed season dates and limits to more evenly
distribute hunting mortality across the entire population structure.
Connelly et al. (2000) state that most greater sagegrouse populations
can sustain hunting if the seasons are carefully regulated. No hunting is permitted in Canada.
Connelly et al. (2000) recommend restricting the number of lek locations provided to the public for viewing to minimize disturbance to grouse during the breeding season. Negative impacts to greater sage grouse from nonconsumptive uses during other seasons have not been identified by the scientific community. Similarly, mortality, either direct or indirect, resulting from scientific research on the greater sagegrouse has not been identified as a limiting factor for this species.
Based on the foregoing discussion, we do not believe there is substantial information available to indicate that, if properly managed, utilization of the greater sagegrouse threatens the continued existence of this species throughout its range.
Under Factor C, the petitions from the Institute for Wildlife Protection and American Lands Alliance et al. discuss predation, but conclude that significant predator impacts to greater sagegrouse, when they occur, are a reflection of anthropogenic impacts to sagegrouse habitat and poor land management.
Greater sagegrouse have many predators, which vary in relative importance to the species, depending on the sex and age of the bird, and the time of year. Adult female greater sagegrouse are most susceptible to predators while on the nest or during broodrearing when they are with young chicks (Schroeder and Baydack 2001). Common nest predators include ground squirrels (Spermophilus spp.), badgers (Taxidea taxus), ravens (Corvus corax), crows (C. brachyrhynchos), magpies (Pica pica), coyotes (Canis latrans), and weasels (Mustela spp.). Juvenile grouse are susceptible to predation from badgers, red foxes (Vulpes vulpes), coyotes, weasels, American kestrels (Falco sparverius), merlins (F. columbarius), northern harriers (Circus cyaneus), and other hawks (Braun in litt. 1995; Schroeder et al. 1999). The mortality rate for juveniles is estimated to be 63 percent during the first few weeks after hatching (Schroeder and Baydack 2001). While chicks are very vulnerable to predation during this period, other causes of mortality, such as weather, are included in this estimate. Adult male sagegrouse are most susceptible to predation during the mating season as they are very conspicuous while performing their mating display. Also, since leks are attended daily, predators may be disproportionately attracted to these areas during the breeding season (Braun in litt. 1995). Common lek predators include golden eagles (Aquila chrysaetos), ferruginous hawks (Buteo regalis), redtailed hawks (B. jamaicensis), Swainson's hawks (B. swainsoni), and other large raptors.
Research conducted to determine nest success and sagegrouse survival has concluded that predation typically does not limit sage grouse numbers (Connelly et al. 2000). However, where sagegrouse habitat has been altered, predation can become more significant (Gregg et al. 1994; Braun in litt. 1995; Braun 1998; DeLong et al. 1995; Schroeder and Baydack 2001). Losses of nesting adult hens and nests appear to be related to the amount of herbaceous cover surrounding the nest (Braun in litt. 1995; Braun 1998; Connelly et al. 2000; Schroeder and Baydack 2001). Removal or reduction of this cover, by any method, can negatively affect nest success and adult hen survival. Similarly, habitat alteration that reduces cover for young chicks can increase the rate of predation on this age class (Schroeder and Baydack 2001). Losses of breeding hens and young chicks can negatively influence overall sagegrouse population numbers, as these two groups contribute most significantly to population productivity. Habitat concerns have not been identified as important factors influencing adult male sage grouse predation rates as leks are relatively open areas with little cover (Schroeder et al. 1999). However, given the sagegrouse breeding system, where only a few males are selected by all the females for mating, loss of some adult males on the lek is not likely to have significant population effects (Braun in litt. 1995). Braun (in litt. 1995) does recommend limiting powerlines and fences within 1.6 km (1 mi) of leks to minimize the availability of raptor perches.
The Institute for Wildlife Protection and American Lands Alliance et al. identify several diseases and parasites that may limit greater sagegrouse populations. However, the petitioners indicate that disease and parasitism are poorly studied in this species (Webb 2002, page 176; American Lands Alliance, page 178).
We agree with the petitioners on the lack of scientific evidence about the effects of disease or parasites on sagegrouse populations, and acknowledge that this factor may be significant to small, isolated populations (Schroeder et al. 1999). We also agree with the petitioners' contention that habitat degradation and fragmentation may increase the effects of disease and parasites on greater sagegrouse. While some research suggests parasites may influence male mating success and evolutionary pathways (Boyce 1990), there is little information to support that disease or parasites are a significant limiting factor in the greater sagegrouse.
We have recently become aware that greater sagegrouse are susceptible to the introduced West Nile Virus (WNV) (Flavivirus), a concern highlighted by American Lands Alliance et al. While the virus has been implicated in the deaths of 24 individuals in Wyoming and Montana, actual population impacts of this disease on sagegrouse are not known. A survey of 111 hunterkilled birds and live birds trapped at sites of WNV activity in Wyoming and Montana revealed that none of the birds had antibody titers against WNV. This evidence is not conclusive and warrants further investigation, but suggests that the number of sagegrouse surviving WNV infection might be small (Dr. Todd Cornish, Wyoming State Veterinary Laboratory, University of Wyoming, pers. comm. 2003). We will continue to monitor this situation.
Based on the preceding discussion, we do not believe there is substantial information available at this time to indicate that disease or predation are factors that may threaten the continued existence of the greater sagegrouse. We will continue to monitor sagegrouse reaction to WNV as the virus becomes more prevalent across the species' range.
Under Factor D, the petitions from the Institute for Wildlife Protection and American Lands Alliance et al. claim that regulations for greater sagegrouse management established by State wildlife agencies are not sufficient to protect the species, because hunting is still permitted. The petitions also state that ``existing regulatory mechanisms are virtually nonexistent'' (Webb 2002, page 177; American Lands Alliance et al., page 180) and current management for the conservation of greater sagegrouse is insufficient.
Greater sagegrouse are under the management authority of State wildlife agencies. Most State agencies base their
[[Page 21492]]
hunting regulations on local population information and peerreviewed
scientific literature regarding the impacts of hunting on the greater
sagegrouse (Bohne in litt. 2003). Hunting seasons are reviewed
annually, and most States implement adaptive management based on
harvest and population data (see previous discussion under Factor B).
A large portion of habitat for the greater sagegrouse occurs on lands managed by the BLM and the U.S. Forest Service (USFS). The BLM has designated the greater sagegrouse as a special status species in 5 of the 11 States in which it currently occurs (Nevada, California, Oregon, Washington, and Wyoming). Management for special status species are addressed under BLM Manual 6840, ``Special Status Species Management.'' This document provides agency policy and guidance for the conservation of special status plants and animals and the ecosystems on which they depend (BLM 2001). Although not a regulatory document, BLM Manual 6840 provides a mechanism for the conservation of the greater sagegrouse and its habitat. At present, there are no regulations requiring that BLM land use plans specifically address the conservation needs of special status species (BLM 2003b).
However, with respect to the sagegrouse, the FWS and BLM are developing strategies for conservation of the species, including BLM's draft interim planning and habitat management guidelines for its lands. FWS and BLM are also working with the States on the Sage Grouse Conservation Planning Framework Team which will produce the rangewide greater sage grouse conservation assessment and the conservation action plans to follow. In addition, BLM is undertaking a number of onthe ground sagebrush habitat restoration projects, while it is working to complete the longerterm joint conservation assessment and planning.
The USFS requires that fish and wildlife habitats be managed to maintain viable populations of existing native vertebrate species (36 CFR 219.19). In addition, each region of the USFS maintains a sensitive species list. The USFS policy requires the agency to employ special management emphasis to ensure the viability of designated sensitive species, and ``to preclude trends towards endangerment that would result in a need for Federal listing'' (USFS 1991). The greater sage grouse is designated as a USFS sensitive species in Regions 1, 2, 4, 5, and 6, which are within the species' range. All National Forests within these regions are required to implement the USFS Sensitive Species Policy (FSM 2672.1) for the greater sagegrouse. In addition, several individual National Forests in Regions where the greater sagegrouse is not designated as a sensitive species have chosen to make the bird a Management Indicator Species (Clinton McCarthy, USFS, pers. comm. 2003). This designation requires the individual National Forest to establish objectives for the maintenance and improvement of habitat for the greater sagegrouse (36 CFR 219.19), and to monitor the status of this species on the National Forest.
Some greater sagegrouse habitat also occurs on lands managed by other Federal agencies, including the Service, National Park Service, Department of Energy, Bureau of Reclamation, and Department of Defense. Some agencies have developed sitespecific plans for conserving sage grouse habitats on their lands (i.e., Yakima Training Center, Seedskadee National Wildlife Refuge) (66 FR 22984). However, we are unaware of any other agency efforts to protect and conserve sagegrouse on these Federal lands. Greater sagegrouse also occur on Native American Tribal lands. In January 2004, the Service provided a Tribal Wildlife Grant to the Shoshone and Arapahoe Joint Council of Wyoming to assist in developing a management plan for the greater sagegrouse and sagebrush habitats on the Wind River Reservation.
The petitions from the Institute for Wildlife Protection and American Lands Alliance et al. assert that all existing State and private conservation planning efforts for sagegrouse are ineffective because no regulatory mechanisms or funding resources are in place to ensure these efforts are implemented. Most of the States within the range of the greater sagegrouse have initiated conservation planning efforts for sagegrouse and sagegrouse habitat on State, private, and, in some cases, Federal lands. The plans are focused on addressing local sagegrouse or sagebrush habitat concerns through a variety of mechanisms (i.e., changes in regulations, habitat improvement projects, etc.). When completed, the Service will review these conservation plans to determine if they are consistent with our Policy for the Evaluation of Conservation Efforts (68 FR 15100). This policy evaluates the likelihood of implementation and effectiveness for each conservation strategy presented. It is currently impossible to evaluate the effectiveness of State and private conservation efforts for the greater sagegrouse, as most are either being drafted or have not been implemented at the time of this finding. The Service is not aware of any State regulations that conserve greater sagegrouse habitat or encourage habitat conservation efforts on private lands.
The greater sagegrouse is listed as an endangered species at the national level in Canada, as well as at the provincial level in Alberta and Saskatchewan. Provincial laws in Saskatchewan prevent sagegrouse habitat from being sold or from having native vegetation cultivated. Individual birds are protected by provincial law in Alberta, but their habitat is not. However, the Province has developed guidelines to protect leks. Passage of the Canadian Species At Risk Act in 2002 allows for habitat regulations to protect sagegrouse (Aldridge and Brigham 2003).
Based on the information currently available to us for this finding, the principal concern regarding the adequacy of regulatory mechanisms is in relation to habitat conservation. The past and ongoing degradation of greater sage grouse habitat, such as habitat conversion, fragmentation, and alteration due to various land use practices (see discussion of Factor A, above), is due in large part to human actions rather than natural events. To the extent that such humancaused habitat degradation is contributing to population declines of greater sage grouse, it indicates that existing regulatory mechanisms, particularly at the Federal level (since most of the habitat is on Federal land), but also at the State, Provincial, and local levels, may be inadequate with regard to addressing threats to the species.
Under Factor E, the petitions from the Institute for Wildlife Protection and American Lands Alliance et al. assert that fences, powerlines, and roads are sources of direct injury and mortality to greater sagegrouse. Fences are a documented collision hazard for sage grouse (Call and Maser 1985; Braun 1998). Over 51,000 km (31,960 mi) of fences were constructed on BLM lands supporting sagegrouse populations between 1962 and 1997 (Connelly et al. 2000). Direct mortality of greater sagegrouse as a result of collision with, and electrocution from, powerlines has been documented (Braun 1998; Aldridge and Brigham 2003). Sagegrouse suffer direct mortality from collisions with automobiles (Hornaday 1916; Braun 1998). To our knowledge, the extent of mortality from these factors has not been quantified. Also, the Service has not found any evidence suggesting that collisions and electrocutions limit greater sagegrouse populations.
The Institute for Wildlife Protection and American Lands Alliance et al. also identify fire as a source of direct
[[Page 21493]]
mortality to the greater sagegrouse. While we agree that some sage
grouse may perish in fires, either wild or prescribed, this mortality
factor has not been identified by the scientific community as a limiting factor for sagegrouse populations.
The petitions from the Institute for Wildlife Protection and American Lands Alliance et al. identify several factors that may be affecting greater sagegrouse populations which are not discussed above. These include mining toxins (such as cyanide), herbicides, pesticides, ozone depletion, endocrine disrupters, pollution, global warming, competition for resources between the greater sagegrouse and other species of grouse and livestock, offroad vehicle and snowmobile use, noise, weather, natural stochastic events, and loss of genetic variation. We know of no scientific information supporting threats to greater sagegrouse populations as a result of ozone depletion, endocrine disrupters, global warming, or pollution. The petitions also do not present supporting scientific information specific to the greater sagegrouse and these threats, but rather draw conclusions based on studies on other species, including humans.
At least one study has documented direct mortality of greater sage grouse as a result of ingestion of alfalfa sprayed with
organophosphorus insecticides (Blus et al. 1989). Direct ingestion of
other herbicides, such as chlordane, also are toxic to sagegrouse
(Schroeder et al. 1999). However, there is little information
supporting the contention that normal use of herbicides negatively
affects greater sagegrouse (Schroeder et al. 1999), and the scientific
community has not identified exposure to these substances as a limiting
factor for this species. Pesticides and herbicides may result in a
reduction of food resources for the greater sagegrouse, particularly
nesting females and chicks (Schroeder et al. 1999). Seventeen different
radionuclides (radioactive atoms) were found in greater sagegrouse
captured near nuclear facilities at the Idaho National Engineering
Laboratory in southeastern Idaho (Connelly and Markham 1983). The
effects of these substances on greater sagegrouse appear to be minimal (Schroeder et al. 1999).
During part of the year, greater sagegrouse distribution may overlap with sharptailed (Tympanuchus phasianellus) and blue (Dendragapus obscurus) grouse in some areas of their ranges. Although it is likely that these species are consuming some of the same foods, there is no information that these resources are limiting and no evidence suggesting competition with other grouse species has negative effects on sagegrouse (John Connelly, Idaho Department of Fish and Game, pers. comm. 2003). Cattle and sheep will consume sagebrush, as well as grass. Sheep also consume rangeland forbs in areas where sage grouse occur (Pedersen et al. 2003). The effects of direct competition between livestock and sagegrouse will depend on condition of the habitat and grazing practices, and thus vary across the range of the species. For example, Aldridge and Brigham (2003) suggest that poor livestock management in mesic sites, which are considered limited habitats for sagegrouse in Alberta, results in a reduction of forbs and grasses available to sagegrouse chicks, thereby affecting chick survival. Livestock may modify sagegrouse habitat by altering vegetation structure and changing composition; this is addressed under Factor A above.
The petitions state that offroad vehicle or snowmobile use affects greater sagegrouse through habitat alteration and degradation, increased stress, and direct mortality. While the petitions do not present supporting scientific information specific to the greater sage grouse, we agree that habitat degradation may occur in areas of off road vehicle and/or snowmobile use throug
FOR FURTHER INFORMATION CONTACT Dr. Pat Deibert, at the address given in the ADDRESSES section (telephone 3077722374; facsimile 307772 2358).
14 CFR Part 39 40 CFR Part 52 14 CFR Part 71 33 CFR Part 165 50 CFR Part 679 26 CFR Part 1 40 CFR Part 180 47 CFR Part 73 50 CFR Part 17 33 CFR Part 117 44 CFR Part 67 50 CFR Part 648 14 CFR Part 97 33 CFR Part 100 40 CFR Part 63 50 CFR Part 622 26 CFR Part 301 39 CFR Part 111 40 CFR Part 300 50 CFR Part 660 44 CFR Part 65 40 CFR Parts 52 and 81 40 CFR Part 271 47 CFR Part 64 50 CFR Part 665 47 CFR Part 76 50 CFR Part 229 14 CFR Part 23 14 CFR Part 25 21 CFR Part 522