Endangered and Threatened Wildlife and Plants; 12-Month Finding for Petitions To List the Greater Sage-Grouse as Threatened or Endangered

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 12-Month Finding for Petitions To List the Greater Sage-Grouse as Threatened or Endangered

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of a 12-month petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding for three petitions to list the greater sage-grouse (

Centrocercus urophasianus

) as threatened or endangered under the Endangered Species Act of 1973, as amended. After reviewing the best available scientific and commercial information, we find that listing is not warranted. We ask the public to submit to us any new information that becomes available concerning the status of or threats to the species. This information will help us monitor and encourage the conservation of this species.

DATES:

The finding announced in this document was made on January 6, 2005. Although further listing action will not result from this finding, we request that you submit new information concerning the status of or threats to this species whenever it becomes available.

ADDRESSES:

Comments and materials received, as well as supporting documentation used in the preparation of this 12-month finding, will be available for inspection, by appointment, during normal business hours at the Wyoming Ecological Services Field Office, U.S. Fish and Wildlife Service, 4000 Airport Parkway, Cheyenne, Wyoming 82001. Submit new information, materials, comments, or questions concerning this species to the Service at the above address.

FOR FURTHER INFORMATION CONTACT:

The Wyoming Field Office (see

ADDRESSES

section above), by telephone at (307) 772-2374, by facsimile at (307) 772-2358, or by electronic mail at

fw6_sagegrouse@fws.gov.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531

et seq.

), requires that, for any petition to revise the Lists of Threatened and Endangered Wildlife and Plants that contains substantial scientific or commercial information that the action may be warranted, we make a finding within 12 months of the date of the receipt of the petition on whether the petitioned action is: (a) Not warranted, (b) warranted, or (c) warranted but precluded by other pending proposals. Such 12-month findings are to be published promptly in the

Federal Register

.

On July 2, 2002, we received a petition from Craig C. Dremann requesting that we list the greater sage-grouse (

Centrocercus urophasianus

) as endangered across its entire range. We received a second petition from the Institute for Wildlife Protection on March 24, 2003 (Webb 2002) requesting that the greater sage-grouse be listed rangewide. 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 sage-grouse as threatened or endangered rangewide. On April 21, 2004, we announced our 90-day petition finding in the

Federal Register

(69 FR 21484) that these petitions taken collectively, as well as information in our files, presented substantial information indicating that the petitioned actions may be warranted. In accordance with section 4(b)(3)(A) of the Act, we have now completed a status review of the best available scientific and commercial information on the species, and have reached a determination regarding the petitioned action.

This status review of the greater sage-grouse does not address our prior finding with regard to the Columbia Basin distinct population segment (DPS). On May 7, 2001, we published a 12-month finding on a petition to list the Washington population of the western subspecies of the greater sage-grouse as a distinct population segment (DPS) (66 FR 22984). Our finding included a summary of the historic distribution of what we then considered to be the western subspecies of the greater sage-grouse (see “Species Information” below regarding taxonomy). In our finding we determined that the population segment that remains in central Washington met the requirements of our policy for recognition as a distinct population segment (61 FR 4722) and that listing the DPS was warranted but precluded by other higher priority listing actions. Because the population in central Washington occurs entirely within the historic distribution of sage-grouse within the Columbia Basin ecosystem, we referred to it as the Columbia Basin DPS (66 FR 22984; May 7, 2001). In subsequent candidate notices of review (CNORs), including the most recent one published in the

Federal Register

on May 4, 2004 (69 FR 24875), we found that a listing proposal for this DPS was still warranted but precluded by higher priorities. Since that time new information has become available through this status review of the greater sage-grouse. We will use the best scientific and commercial information available (including, but not limited to information that became available during this rangewide status review) to reevaluate whether the Columbia Basin population still qualifies as a DPS under our DPS policy, and if it does, whether the DPS still warrants a listing proposal. Once that evaluation is completed, we will publish an updated finding for the Columbia Basin population in the

Federal Register

either in the next CNOR or in a separate notice.

Responses to Comments Received

We received 889 responses to our request for additional information in our 90-day finding for the greater sage-grouse (69 FR 21484). Those responses which contained new, updated, or additional information were thoroughly considered in this 12-month finding. We received a large number of identical or similar comments. We consolidated the comments into several categories, and provide responses as follows.

Comment 1:

It is premature for the Service to consider listing the sage-grouse until the impact of local and State conservation efforts are realized.

Response 1:

The Service is required under section 4 of the Act to determine whether or not listing is warranted within 12 months of receiving a petition to list a species. By publishing a positive 90-day finding in April, 2004 (69 FR 21484), we were required by the Act to immediately proceed with the completion of a 12-month finding. We have examined ongoing and future conservation efforts in our status review. This included using our Policy for Evaluation of Conservation Efforts When Making Listing Decisions (“PECE”) (68 FR 15100; March 28, 2003) to evaluate conservation efforts by State and local governments and other entities that have been planned but have not been implemented, or have been implemented but have not yet demonstrated effectiveness, to determine which such efforts met the standard in PECE for contributing to our finding. Our analysis of the best available scientific data revealed that the greater sage-grouse is not a threatened species, and in making this finding it was not necessary to rely on the contributions of any of the local, State, or other planned conservation efforts that met the standard in PECE. A

summary of our process with regard to PECE is provided in the section “Status Review Process,” below.

Comment 2:

Listing the sage-grouse could have a negative impact on the conservation efforts being implemented by States for this species.

Response 2:

We appreciate the fact that prior to acceptance of the listing petitions, States within the range of the greater sage-grouse are fully engaged in developing and implementing conservation efforts for this species, and we encourage them to continue these efforts. Conservation actions which have already been implemented have been considered in this decision. However, our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of population status and threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision.

Comment 3:

The facts do not support the need for listing this species.

Response 3:

The Service has considered all factors potentially affecting the greater sage-grouse in our decision and agree that the listing is not warranted. We have made our decision based on the best available scientific and commercial data, as required by the Act.

Comment 4:

In most western states, sage-grouse populations have been fairly steady and in some cases, increasing over the past decade.

Response 4:

The Service has considered population trends in all States and Provinces, and across the entire range of the species in our status review, including localized increases.

Comment 5:

Locally managed efforts are best suited to preserve and protect the greater sage-grouse.

Response 5:

We acknowledge that local conservation efforts for this species are important to long-term conservation, particularly given the widespread distribution and the variety of habitats and threats. However, most of these efforts have not yet been implemented, or have not been demonstrated to be effective. Conservation actions that have already been implemented and for which effectiveness is known have been considered in this decision. Our determination of whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision. There is no one best strategy for sage-grouse conservation and we encourage the continuation of all conservation efforts to conserve the greater sage-grouse. The Service continues to support the development of a Conservation Strategy for the Greater Sage-grouse by Western Association of Fish and Wildlife Agencies (WAFWA), and supports voluntary conservation as the most effective method to protect species and their habitats.

Comment 6:

The recovery process under the Endangered Species Act has a very low success rate.

Response 6:

Our decision regarding the greater sage-grouse is a listing, not a recovery decision. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not its potential for recovery under the Act. Therefore, this comment may not be considered in this finding.

Comment 7:

If the greater sage-grouse is listed there will be a reduction of freedom and private property rights and public land use, and therefore a negative impact on the country. Listing the grouse will also result in economic damage to many entities.

Response 7:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential social or economic implications of listing. Therefore, this comment may not be considered in this finding.

Comment 8:

There will be a loss of management options for the greater sage-grouse if this species is listed.

Response 8:

We are not aware of any management options that are beneficial to the greater sage-grouse that would need to be eliminated if this species is listed under the Act-an action we believe to be not warranted at this time.

Comment 9:

Listing the greater sage-grouse will divide and polarize local communities.

Response 9:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential socio-political implications of listing. Therefore, this comment may not be considered in this finding.

Comment 10:

Listing the greater sage-grouse will increase the workload for the U.S. Fish and Wildlife Service.

Response 10:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential increase in workload for the Service. Therefore, this comment may not be considered in this finding.

Comment 11:

Listing the greater sage-grouse will result in Federal budget limitations for other Federal agencies and projects.

Response 11:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential implications for the Federal budget of listing. Therefore, this comment may not be considered in this finding.

Comment 12:

Conservation planning efforts and current Federal agency actions are sufficient to conserve the greater sage-grouse.

Response 12:

We acknowledge that many Federal agencies are implementing conservation measures for the greater sage-grouse, and that several conservation efforts for this species are underway. Current federal conservation efforts have been reviewed and considered in our analysis. We evaluated planned conservation efforts under PECE (see Response 1); most of the planned conservation efforts for the greater sage-grouse have not yet been implemented. However, because our analysis of the best available scientific and commercial data revealed that the greater sage-grouse is not warranted for listing under the ESA, it was not necessary to evaluate whether the planned conservation efforts that met PECE reduced the threats to the species.

Comment 13:

The petition was subjected to an independent analysis and serious problems were found with the science.

Response 13:

Our 90-day finding was based on the determination that the three petitions submitted met the “substantial information” threshold as defined under section 4(b)(3)(A) of the Act. At the time of the 90-day finding, we did acknowledge that two of the three petitions contained some misstatements (69 FR 21484). However, the petitions were only one information source of many we used in our review for the 90-day finding. For the current 12-month finding, we conducted an exhaustive review of the scientific literature, and included State, industry, and Federal agency data. This finding does not rely on the petitions, but rather the best scientific and commercial data available, as required by the Act.

Comment 14:

The Western Governor's Association report provides additional information which should be considered.

Response 14:

The Western Governor's Association report was considered in this finding.

Comment 15:

Many private sector groups are taking steps to protect sage-grouse habitat.

Response 15:

We acknowledge that local conservation efforts for this species are important to long-term conservation and strongly support the continuation of these efforts. Most of the planned conservation efforts for the greater sage-grouse have not yet been implemented. As explained above, in making this finding it was not necessary to rely on the contributions of any of the local, State, or other planned conservation efforts that met the standard in PECE (

see

Response 1).

Comment 16:

Scientific reports detailing the sage-grouse's decline consistently declare more work is necessary to adequately assess the status of sage-grouse populations.

Response 16:

We agree that additional information on populations would be useful. However, as required by the Act, the Service must use the best scientific and commercial information available when making a 12-month finding. The law does not provide a mechanism for the Service to improve the available information.

Comment 17:

Hunting is allowed in most states and provides a benefit to hunters and state wildlife programs without a negative impact on sage-grouse populations.

Response 17:

At this time, it is unclear what area-specific impacts sage-grouse hunting has on sage-grouse populations. Most States are currently managing their populations in conformance with the WAFWA guidelines, which contain the most up-to-date guidelines for sage-grouse management. Our review indicated that regulated hunting of sage-grouse does not pose a threat that would lead to the likely endangerment of the species in the foreseeable future.

Comment 18:

Now that there is a coordinated effort to further protect the species, there is no reason to suspect that this progress will not continue.

Response 18:

We acknowledge that many Federal, State, and local working groups are implementing protective measures for the greater sage-grouse, and that several conservation efforts for this species are underway, have been planned, or are in the process of being planned. Most of the planned conservation efforts for the greater sage-grouse have not yet been implemented. As explained above, in making this finding it was not necessary to rely on the contributions of any of the local, State, or other planned conservation efforts that met the standard in PECE (

see

Response 1). We strongly encourage continued efforts to preserve and protect the greater sage-grouse and its habitat.

Comment 19:

The Conservation Assessment of Greater Sage-grouse and Sagebrush Habitats provides additional information which should be considered.

Response 19:

The Conservation Assessment of Greater Sage-grouse and Sagebrush Habitats report was considered in this finding.

Comment 20:

The worst possible outcome is to list the sage-grouse.

Response 20:

Our determination of whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision. We strongly encourage all efforts to conserve the greater sage-grouse and its habitat.

Comment 21:

Predators are causing the decline of sage-grouse.

Response 21:

We have considered the effects of predators and predator control in our sage-grouse analysis.

Comment 22:

We need to consider the effects of hunting on sage-grouse.

Response 22:

We have considered the effects of hunting in our sage-grouse analysis.

Comment 23:

Sage-grouse are doing well in some areas and therefore, they should not be listed in those areas. Also, the Service should consider the need to list sage-grouse on a state-by-state basis.

Response 23:

The petitions requested that we determine if the species needed to be listed across its entire range. Therefore, we have to consider the sage-grouse population range-wide. Additionally, our Policy Regarding the Recognition of Distinct Vertebrate Populations (61 FR 4722) requires that in order to consider separate populations within a species for listing under the Act, such populations must (1) be discrete in relation to the remainder of the species to which it belongs, and (2) have biological and ecological significance for the taxon. We have received no information that suggests any population of the greater sage-grouse is isolated from conspecific populations, with the exception of the Columbia Basin population in central Washington. As described above, we previously determined that a proposal to list the Columbia Basin distinct population segment is warranted but precluded by other higher priority listing actions (66 FR 22984), and in the near future we will reevaluate that determination to consider new information, including (but not limited to) information available as a result of this status review and finding on petitions to list the greater sage-grouse.

Comment 24:

Drought and other weather conditions have had a major effect on sage-grouse populations.

Response 24:

We acknowledge that drought and other weather conditions are a natural occurrence in the west and we have considered the effects of drought in our sage-grouse analysis.

Comment 25:

It was interesting to see flocks of dozens of grouse near fences, since conventional wisdom sees fences as perches for raptors and hence areas of avoidance for raptor-wary grouse.

Response 25:

We acknowledge that raptors do use fences as perch sites. Sage-grouse tend to avoid perch sites like fences but threats of raptors do not totally exclude sage-grouse use of habitat near fences.

Comment 26:

The size of sage-grouse populations can be affected by habitat condition.

Response 26:

We acknowledge that habitat conditions can affect local sage-grouse numbers. We have considered this information in the finding.

Comment 27:

Disease is a natural event that may be negatively affecting sage-grouse.

Response 27:

We have considered the effects of disease on greater sage-grouse in this finding. As identified in the Act, it is one of the threat factors we are required to consider in our status review.

Comment 28:

Listing the greater sage-grouse will remove the flexibility of local planning efforts.

Response 28:

We recognize that listing may affect local planning efforts, due to its effect on voluntary conservation efforts. However, we may not consider those effects under this status review.

Comment 29:

Maintaining and improving habitat is the answer to increasing sage-grouse numbers.

Response 29:

We concur that maintaining habitat is important for the long-term conservation of the greater sage-grouse. We strongly encourage efforts to conserve sage-grouse and sagebrush habitat.

Comment 30:

Greater sage-grouse numbers and distribution have significantly declined since 1900.

Response 30:

The information pertaining to the status and distribution of the greater sage-grouse has been reviewed and incorporated in our analysis. Sage-grouse abundance has been scientifically documented as declining since the 1950s, but the rate of decline has decreased since the 1980s and in some places has stabilized, or even increased.

Comment 31:

Destructive land use practices and management on public and private lands are negatively affecting the greater sage-grouse.

Response 31:

We have considered the effects of various uses of private and public lands on the status of the greater sage-grouse in this finding.

Comment 32:

Negative impacts to the greater sage-grouse continue irrespective of efforts by State and local working groups.

Response 32:

Most State and local working group conservation efforts for the greater sage-grouse have not yet been implemented, and the certainty of implementation and effectiveness of such efforts is unclear. However, we have considered all conservation efforts which have been implemented and shown to be effective. As explained above, in making this finding it was not necessary to rely on the contributions of any of the local, state, or other planned conservation efforts that met the standard in PECE (

see

Response 1).

Comment 33:

Listing the sage-grouse would affect much-needed land management reform.

Response 33:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential land management implications of listing. Therefore, this comment may not be considered in this finding.

Comment 34:

The ESA requires that listing decisions be based solely on the best science and biological information about the species and its habitats.

Response 34:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act.

Comment 35:

Meaningful regulatory mechanisms are non-existent and existing management is inadequate to conserve the bird.

Response 35:

We have considered existing regulatory mechanisms and management activities in this finding.

Comment 36:

Only listing the greater sage-grouse under the Endangered Species Act will save the birds and its habitat.

Response 36:

Our determination of whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision. We strongly encourage all efforts to conserve the greater sage-grouse and its habitat.

Comment 37:

Listing the greater sage-grouse would benefit a variety of other sagebrush obligates and sagebrush-dependent species.

Response 37:

This finding is for the greater sage-grouse only. Therefore, we cannot consider the potential impact of listing the greater sage-grouse on the status of other sagebrush-dependent species in our decision.

Comment 38:

The WAFWA Conservation Assessment is disturbing in that its findings show a wide discrepancy in how States monitor greater sage-grouse.

Response 38:

The WAFWA Conservation Assessment represents one component of the best available scientific and commercial data that we used in our analysis, as required by the Act. The fact that the States vary somewhat in how they conduct monitoring of this species was considered in this finding.

Comment 39:

The loss of small populations of sage-grouse increases the species' risk of extinction when the species occurs primarily in spread out, island-like patches of habitat.

Response 39:

We have considered the effects of small population sizes and isolated populations in our finding.

Comment 40:

Current regulatory frameworks are sufficient to protect the greater sage-grouse.

Response 40:

We have considered existing regulatory mechanisms and management activities in this finding and determined that existing regulatory protections in combination with the existing threats do not warrant listing the greater sage-grouse range-wide.

Comment 41:

Grazing is good for sage-grouse. Improvements to grazing practices have been positive for sage-grouse.

Response 41:

We have considered all aspects of grazing impacts on the greater sage-grouse in our finding.

Comment 42:

Listing the greater sage-grouse will curtail energy development.

Response 42:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential land management implications of listing. We did evaluate the threat of energy development to greater sage-grouse in this finding.

Comment 43:

ESA is prohibitively expensive to implement.

Response 43:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential cost of listing. Therefore, this comment may not be considered in this finding.

Comment 44:

There is adequate funding available for future conservation efforts for the greater sage-grouse.

Response 44:

We evaluated the certainty of funding for future conservation efforts as part of our evaluation of efforts that were subject to PECE. We encourage the continued implementation of conservation efforts for the greater sage-grouse.

Comment 45:

We have additional information for your analysis.

Response 45:

All relevant additional, new, or updated information received in comments submitted was thoroughly considered in this 12-month finding.

Comment 46:

We have information regarding proposed actions for your analysis.

Response 46:

We have examined proposed actions, consistent with PECE (68 FR 15100) in our status review. Our analysis of the best available scientific and commercial data revealed that listing the greater sage-grouse as threatened or endangered is not warranted, and in making this finding it was not necessary to rely on the

contribution of any of the local, State, or other planned conservation efforts that met the standard in PECE (

see

Response 1).

Comment 47:

The Service's 90-day finding did not consider all available information.

Response

47: For a 90-day finding, we are required to review the information in the petition(s), our files, and any information provided by States and Tribes. Based upon this information, the Service determines whether there is substantial information indicating that further review is necessary. We are required to consider the best available scientific and commercial data in our 12-month status review. This finding represents our conclusions based on that information.

Comment 48:

Falconers take very few sage-grouse. They are a preferred species for only one extremely specialized form of falconry.

Response 48:

We have considered this information in our analysis.

Comment 49:

If the Service determines that listing the sage-grouse is appropriate, they will have to designate critical habitat.

Response 49:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision. We designate critical habitat for listed species as required by the Act.

Comment 50:

The Service must consider the status of the sage-grouse across the entirety of its range.

Response 50:

We have considered the status of the greater sage-grouse across the entirety of its range, as petitioned.

Comment 51:

We do not believe that the designation of the Washington population of sage-grouse as a Distinct Population Segment (DPS) is appropriate.

Response 51:

This status review of the greater sage-grouse does not address our prior finding with regard to the Columbia Basin distinct population segment (DPS). New information which has become available through this status review of the greater sage-grouse will be considered when we re-evaluate the status of the Columbia Basin population, either through an updated finding or in the next Candidate Notice of Review.

Comment 52:

Managing agencies lack Best Management Practices due to the lack of support, manpower, and funding.

Response 52:

We acknowledge that the extent of support, manpower, and funding may influence some aspects of the implementation of Best Management Practices (BMPs) for sage-grouse. As currently described, most BMPs are very broadly stated mitigation measures that involve incorporating project design features when various resource management activities are planned, in order to reduce or avoid impacts to species.

Comment 53:

Industry has implemented many mitigation and protection measures for sage-grouse.

Response 53:

We acknowledge that industries are implementing some mitigation and protective measures for sage-grouse. We evaluated all such information that was available to us. We strongly encourage the continuation of all efforts to conserve the greater sage-grouse and its habitat.

Comment 54:

Listing the sage-grouse could have profound impacts on a number of military facilities.

Response 54:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, not the potential impact of listing on military facilities. Therefore, this comment may not be considered in this finding.

Comment 55:

Loss of habitat to cheatgrass and juniper invasion are major threats to sage-grouse habitat. The technologies and know-how exist to eliminate or reduce the cheatgrass and juniper invasion trends.

Response 55:

We acknowledge that cheatgrass and juniper invasions are threats to sage-grouse habitats. Currently, technologies have been developed or are being developed to treat problems of cheatgrass and juniper invasions. Our review found mixed results in the current technologies' ability to treat cheatgrass and juniper problems.

Comment 56:

Historic declines and habitat loss are not relevant to the current listing decision.

Response 56:

Our decision regarding the greater sage-grouse is based on the best available scientific and commercial data, as required by the Act. Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision, including information on historic declines and habitat loss to the extent that they contribute to current threats.

Comment 57:

There is no peer-reviewed science to support a listing.

Response 57:

We have reviewed scientific, peer-reviewed literature in our analysis, as well as commercial and unpublished data. The cumulative review of this information was used to determine if the greater sage-grouse warrants listing under the Endangered Species Act.

Comment 58:

Most sage-grouse habitat loss due to agriculture (

i.e.

, conversion to cropland, seeding to crested wheatgrass, etc.) has been eliminated or greatly reduced. Large-scale conversions to agriculture are decreasing.

Response 58:

We acknowledge that there have been changes in the rate of loss of sage-grouse habitat due to various agricultural conversions. We have considered this information in our analysis.

Comment 59:

The Service must consider all listing factors when making a determination.

Response 59:

Our determination regarding whether or not this species warrants listing under the Act must be based on our assessment of the threats to the species, the species' population status, and the status and trend of the species' habitat as they are known at the time of the decision. We consider the effects of all threats on the status of the species when we make our determination.

Comment 60:

Present habitat provides the necessary elements to sustain a highly viable sage-grouse population.

Response 60:

We have considered existing habitat conditions for the greater sage-grouse throughout its range in this finding.

Comment 61:

There is insufficient funding available to adequately fund existing and proposed conservation plans for the greater sage-grouse.

Response 61:

We have examined ongoing and future conservation efforts in our status review. We have examined proposed actions, consistent with PECE (68 FR 15100), in our status review, and this included consideration of funding, consistent with one of the criteria in PECE. (

See also

Response 1, above).

Comment 62:

Wildfire is a threat to sage-grouse habitat and can result in habitat elimination across the species' range.

Response 62:

We have considered the effects of wildfire on sage-grouse habitat in this finding.

Information Quality Act

In addition to the comments received, two Information Quality Act challenges were submitted. The challenge received from the Partnership for the West was addressed through a response directly to that organization. The second challenge from the Owyhee County Commissioners (Idaho) primarily stated that we failed to conduct an exhaustive search of all scientific literature, and other information in the completion of our 90-day finding. Section 4(b)(3)(A) of the Act only requires that the petitions present “substantial scientific or commercial information indicating that the petitioned action may be warranted.” The Act does not require an exhaustive search of all available information at that time. Other concerns identified in the Owyhee County Commissioner's challenge are addressed in our comment responses above, and an overall summary regarding the steps we have taken to ensure conformance with our Information Quality Guidelines is provided below.

The Service's Information Quality Guidelines define quality as an encompassing term that includes utility, objectivity, and integrity. Utility refers to the usefulness of the information to its intended users, including the public. Objectivity includes disseminating information in an accurate, clear, complete, and unbiased manner and ensuring accurate, reliable, and unbiased information. If data and analytic results have been subjected to formal, independent, external peer review, we generally will presume that the information is of acceptable objectivity. Integrity refers to the security of information—protection of the information from unauthorized access or revision, to ensure that the information is not compromised through corruption or falsification.

The Service conducted a thorough pre-dissemination review of the data it is relying on to make this 12-month finding. In particular, the Service used the information in the WAWFA Conservation Assessment, which is a peer-reviewed science document. The WAWFA assessment was based on data provided by the states, provinces, land management agencies, as well as data in published, peer-reviewed manuscripts and other verified sources available to the authors of the assessment. The draft final assessment was reviewed by State agency wildlife biologists to ensure that data submitted by each State were presented accurately and completely. The assessment also was peer reviewed by an independent group of scientists selected by the Ecological Society of America. These reviewers were experts from academia, government, and non-governmental organizations, and included researchers as well as wildlife managers.

The WAWFA Conservation Assessment assembles in one place almost all of the available pertinent data that addresses the current biological and ecological condition of the sage-grouse and its habitat. This compilation of material allows the public to see a large body of information all in one document, making the information more useful than the many separate sources of information would be. Since the document has been subject to an independent, external peer review, the Service believes it is of acceptable objectivity. For these reasons the Service believes this information meets our Information Quality Guidelines.

Status Review Process

Section 4(b)(1)(A) of the Act requires us to consider the best scientific and commercial data available as well as efforts being made by States or other entities to protect a species when making a listing decision. To meet this standard we systematically collected information on the greater sage-grouse, its habitats, and environmental factors affecting the species, from a wide array of sources. The scientific literature on greater sage-grouse and sagebrush habitats is extensive. In addition we received a substantial amount of unpublished information from other Federal agencies, States, private industry and individuals. We also solicited information on all Federal, State, or local conservation efforts currently in operation or planned for either the greater sage-grouse or its habitats.

The current distribution of greater sage-grouse and sagebrush habitat encompasses parts of 11 states in the western United States and 2 Canadian provinces (Figure 1). This large geographical scale combined with major ecological differences in sagebrush habitat and myriad of activities occurring across this large area required that the Service employ a structured analysis approach. Given the very large body of information available to us for our decision, structuring our analysis ensured we could explicitly assess the relative risk of changes occurring across the range of the sage-grouse, and integrate those individual assessments, be they regional or rangewide in nature, into an estimate of the probability that sage-grouse would go extinct at defined timeframes in the future. Using such extinction risk analysis to frame listing decisions under the Act has been recommended (National Research Council 1995), and was adopted by the Service as an important component of a structured analysis of the status review of the greater sage-grouse.

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As part of the structuring of this status review, the Service compiled from the best scientific and commercial data available a summary of the changes or impacts occurring to the sagebrush ecosystem that could potentially affect the sage-grouse directly or indirectly. This summary, or synthesis of biological information, was one of many sources of information provided to a panel of seven experts, who, through a two-day facilitated process discussed threats to the species and each generated an estimate of extinction risk for the greater sage-grouse at different timeframes in the future. This information and all other available information were then considered by Service biologists and managers to frame a listing recommendation, and ultimately the decision reported in this finding.

Expert panels are not a required component of structured analysis but are used to help inform decision makers when there is uncertainty (National Research Council 1995). Typically, this uncertainty is due to a lack of information. While the scientific information on greater sage-grouse and their habitats is extensive, substantial gaps and uncertainty remain in the scientific community's knowledge of all the factors that may affect sage-grouse populations across such a wide geographical range encompassing major ecological differences in sagebrush habitats. Further, scientific knowledge of how the species may respond to those factors over time is incomplete. For these reasons, we requested input from scientific experts outside the Service to help us make a reasonable projection of the species' potential extinction risk. The panel consisted of experts in sage-grouse biology and ecology, sagebrush community ecology, and range ecology and management.

The organization of this finding reflects this basic approach. We first describe in more detail the structured process; present a summary of the threats to the species organized according to the 5 listing factors in the Act; then we present results from the facilitated expert panel process, including estimates of extinction risk; and finally present how a team of Service biologists and managers interpreted the extinction risk analysis, the threat ranking of the expert panelists, and other available information in the context of a listing decision under the Act. In order to ensure that the process we used to reach our finding is transparent, discussion of the biological significance of each threat listed under the 5 listing factors, and the geographical scale at which they affect sage-grouse is based on results of the expert panel and decision support team process. A thorough description of this process and its results is presented later in the finding along with the decision support team's evaluation of the threats in the context of a listing decision under the Act. However, we felt it was important to include a brief discussion of the spatial and biological significance of each threat as they are presented by listing factor.

Following compilation of the best available scientific and commercial information, which is summarized in other sections of this finding and available in full in our administrative record, we conducted three phases of information synthesis and evaluation. First, the information on individual planned conservation efforts was evaluated under PECE to determine which efforts met the following standard in PECE: “To consider that a formalized conservation effort(s) contributes to forming a basis for not listing a species or listing a species as threatened rather than endangered, we must find that the conservation effort is sufficiently certain to be implemented and effective so as to have contributed to the elimination or adequate reduction of one or more threats to the species identified through the section 4(a)(1) analysis” (

see

68 FR 15115). Second, we completed a structured analysis of greater sage-grouse extinction risk including the evaluation of all factors that may be contributing to the species' population trends and the likelihood of the species' extinction at various timeframes into the future. Finally, we evaluated whether the available information on status, trends, ongoing conservation efforts, and potential extinction risk indicate that the greater sage-grouse should be listed as a threatened or endangered species. We further structured these three phases by differentiating two distinct stages of the status review: (1) A risk analysis phase which consisted of compiling biological information, conducting the PECE analysis, and assessing the risk of extinction of greater sage-grouse, and (2) a risk management phase where a decision support team of senior Service biologists and managers evaluated whether or not the potential threats identified as part of our section 4(a)(1) analysis, and summarized in this finding, are significant enough to qualify the greater sage-grouse as a threatened or endangered species under the Act.

For the PECE analysis, we received and reviewed 27 plans, or conservation strategies, outlining more than 300 individual efforts. Most of the plans were from States, but we also received information from the Department of Energy (DOE), Bureau of Land Management (BLM), U.S. Forest Service (USFS), Department of Defense (DOD), Natural Resources Conservation Service (NRCS), Western Governor's Association (WGA), and the North American Grouse Partnership (NAGP).

Each effort within each plan was evaluated under PECE, which provides a framework and criteria for evaluating conservation efforts that have not yet been implemented or have not yet demonstrated whether they are effective at the time of a listing decision. Recognizing that the certainty of implementation and effectiveness of various efforts within a conservation plan, strategy, or agreement may vary, PECE requires that we evaluate each effort individually, and the policy provides criteria to direct our analysis. PECE specifies that “Those conservation efforts that are not sufficiently certain to be implemented and effective cannot contribute to a determination that listing is unnecessary or a determination to list as threatened rather than endangered” (

see

68 FR 15115). As described above, when determining whether or not a species warrants listing, with regard to conservation efforts that are subject to PECE we may only consider those efforts that we are sufficiently certain to be implemented and effective so as to have contributed to the elimination or reduction of one or more threats to the species. Using the criteria provided in PECE, we determined that 20 of the individual efforts we evaluated met the standard for being sufficiently certain to be implemented and effective in reducing threats. Hence, we included those 20 efforts in the information used for the extinction risk evaluation.

The expert panelists participated together in a series of facilitated exercises and discussions addressing first the species' inherent biological vulnerability and resilience, then the potential, relative influence of extrinsic or environmental factors on populations, and finally the experts' projections of extinction risk at different geographical scales both with and without the 20 planned conservation efforts from the PECE analysis. The Service would only consider the effect of the conservation efforts that met PECE in our decision if our review of the best available scientific and commercial data revealed that listing the greater sage-grouse under the Act was warranted. The experts participated only in the assessment of biological and environmental factors and related extinction risk without any consideration or discussion of the petition or regulatory classification of

the species. Structuring of the assessment facilitated thorough and careful deliberation by the experts and observing Service biologists and managers on the decision support team, including clarification of what information was critical to forming the experts' views of, where knowledge gaps and areas of uncertainty exist, and confidence experts felt in the biological judgments they expressed. Structuring also facilitated independent contributions from the experts.

In the final status review stage, following the compilation of biological information, PECE analysis of conservation efforts, and the facilitated extinction risk assessment by the expert panel, Service biologists and managers met and conducted a separate facilitated process to assess whether or not the threats to the greater sage-grouse described in this finding were significant enough at this time to meet the definition of a threatened or endangered species under the Act. Specific results from both the facilitated risk analysis stage of the status review and the facilitated risk management stage of the status review are presented later in the finding to clarify how the Service reached its decision. The Service's finding considered all of the available information on record.

Species Information

The sage-grouse 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 of the head and neck, and white feathers forming a ruff around the neck and upper belly. During breeding displays, males exhibit olive-green apteria (fleshy bare patches of skin) on their breasts (Schroeder

et al.

1999).

In 2000, the species was separated into 2 distinct species, the greater sage-grouse (

C. urophasianus

) and the Gunnison sage-grouse (

C. minimus

) based on genetic, morphological and behavioral differences (Young

et al.

2000). This finding only addresses the greater sage-grouse.

Although the American Ornithological Union (AOU) recognizes two subspecies of the greater sage-grouse, the eastern (

C. u. urophasianus

) and western (

C. u. phaios

), based on research by Aldrich (1946), recent genetic analyses do not support this delineation (Benedict

et al.

2003; Oyler-McCance

et al.

in press). There are no known delimiting differences in habitat use, natural history, or behavior between the two subspecies. Therefore, the Service no longer acknowledges the subspecies designation (68 FR 6500; February 7, 2003; 69 FR 933; January 7, 2004).

Sage-grouse depend on a variety of shrub-steppe habitats throughout their life cycle, and are considered obligate users of several species of sagebrush (

e.g.,

Wyoming big sagebrush (

Artemisia tridentata wyomingensis

), mountain big sagebrush (

A. t. vaseyana

), and basin big sagebrush (

A. t. tridentata

) (Patterson 1952; Braun

et al.

1976; Connelly

et al.

2000a; Connelly

et al.

2004)). Sage-grouse also use other sagebrush species such as low sagebrush (

A. arbuscula

), black sagebrush (

A. nova

), fringed sagebrush (

A. frigida

) and silver sagebrush (A. cana) (Schroeder

et al.

1999; Connelly

et al.

2004). Thus, sage-grouse distribution is strongly correlated with the distribution of sagebrush habitats (Schroeder

et al.

2004). While sage-grouse are dependent on large, interconnected expanses of sagebrush (Patterson 1952; Connelly

et al.

2004), information is not available regarding minimum sagebrush patch sizes required to support populations of sage-grouse. Sage-grouse exhibit strong site fidelity (loyalty to a particular area) for breeding and nesting areas (Connelly

et al.

2004).

During the spring breeding season, male sage-grouse gather together to perform courtship displays on display areas called leks. Areas of bare soil, short-grass steppe, windswept ridges, exposed knolls, or other relatively open sites may serve as leks (Patterson 1952; Connelly

et al.

2004 and references therein). Leks are often surrounded by denser shrub-steppe cover, which is used for escape, thermal and feeding cover. Leks can be formed opportunistically at any appropriate site within or adjacent to nesting habitat (Connelly

et al.

2000a), and therefore lek habitat availability is not considered to be a limiting factor for sage-grouse (Schroeder 1997). Leks range in size from less than 0.04 hectare (ha) (0.1 acre (ac)) to over 36 ha (90 ac) (Connelly

et al.

2004) and can host from several to hundreds of males (Johnsgard 2002). 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 each lek (Schroeder

et al.

1999).

Sage-grouse typically select nest sites under sagebrush cover, although other shrub or bunchgrass species are sometimes used (Klebenow 1969; Connelly

et al.

2000a; Connelly

et al.

2004). The sagebrush understory of productive nesting areas contains native grasses and forbs, with horizontal and vertical structural diversity that provides an insect prey base, herbaceous forage for pre-laying and nesting hens, and cover for the hen while she is incubating (Gregg 1991; Schroeder

et al.

1999; Connelly

et al.

2000a; Connelly

et al.

2004). Shrub canopy and grass cover provide concealment for sage-grouse nests and young, and are critical for reproductive success (Barnett and Crawford 1994; Gregg

et al.

1994; DeLong

et al.

1995; Connelly

et al.

2004). Vegetation characteristics of nest sites, as reported in the scientific literature have been summarized by Connelly

et al.

(2000a). Females have been documented to travel more than 20 km (12.5 mi) to their nest site after mating (Connelly

et al.

2000a), but distances between a nest site and the lek on which breeding occurred is variable (Connelly

et al.

2004). While earlier studies indicated that most hens nest within 3.2 km (2 mi) of a lek, more recent research indicates that many hens actually move much further from leks to nest based on nesting habitat quality (Connelly

et al.

2004). Research by Bradbury

et al.

(1989) and Wakkinen

et al.

(1992) demonstrated that nest sites are selected independent of lek locations.

Sage-grouse clutch size ranges from 6 to 13 eggs (Schroeder

et al.

2000). Nest success (one or more eggs hatching from a nest), as reported in the scientific literature, ranges from 15 to 86 percent of initiated nests (Schroeder

et al.

1999), and is typically lower than other prairie grouse species (Connelly

et al.

2000a) and therefore indicative of a lower intrinsic (potential) population growth rate than in most game bird species (Schroeder

et al.

1999). Renesting rates following nest loss range from 5 to 41 percent (Schroeder 1997).

Hens rear their broods in the vicinity of the nest site for the first 2 to 3 weeks following hatching (Connelly

et al.

2004). Forbs and insects are essential nutritional components for chicks (Klebenow and Gray 1968; Johnson and Boyce 1991; Connelly

et al.

2004). Therefore, early brood-rearing habitat must provide adequate cover adjacent to areas rich in forbs and insects to assure chick survival during this period (Connelly

et al.

2004).

Sage-grouse move from sagebrush uplands to more mesic areas during the late brood-rearing period (3 weeks post-hatch) in response to summer desiccation of herbaceous vegetation (Connelly

et al.

2000a). Summer use areas can include sagebrush habitats as well as riparian areas, wet meadows and alfalfa fields (Schroeder

et al.

1999). These areas provide an abundance of forbs and insects for both hens and chicks (Schroeder

et al.

1999; Connelly

et al.

2000a). Sage-grouse will use free water although they do not require it since they obtain their water needs from the food they eat. However, natural water bodies and reservoirs can provide mesic areas for succulent forb and insect production, thereby attracting sage-grouse hens with broods (Connelly

et al.

2004). Broodless hens and cocks will also use more mesic areas in close proximity to sagebrush cover during the late summer (Connelly

et al.

2004).

As vegetation continues to desiccate through the late summer and fall, sage-grouse shift their diet entirely to sagebrush (Schroeder

et al.

1999). Sage-grouse depend entirely on sagebrush throughout the winter for both food and cover. Sagebrush stand selection is influenced by snow depth (Patterson 1952; Connelly 1982 as cited in Connelly

et al.

2000a), and, in some areas, topography (Beck 1977; Crawford

et al.

2004).

Many populations of sage-grouse migrate between seasonal ranges in response to habitat distribution (Connelly

et al.

2004). Migration can occur between winter and breeding/summer areas, between breeding, summer and winter areas, or not at all. Migration distances of up to 161 kilometers (km) (100 mi) have been recorded (Patterson 1952); however, average individual movements are generally less than 34 km (21 mi) (Schroeder

et al.

1999). Migration distances for female sage-grouse generally are less than for males (Connelly

et al.

2004). Almost no information is available regarding the distribution and characteristics of migration corridors for sage-grouse (Connelly

et al.

2004). Sage-grouse dispersal (permanent moves to other areas) is poorly understood (Connelly

et al.

2004) and appears to be sporadic (Dunn and Braun 1986).

Sage-grouse typically live between 1 and 4 years, but individuals up to 10 years of age have been recorded in the wild (Schroeder

et al.

1999). Juvenile survival (from hatch to first breeding season) is affected by food availability, habitat quality, harvest, and weather. Documented juvenile survival rates have ranged between 7 and 60 percent in a review of many field studies (Crawford

et al.

2004). The average annual survival rate for male sage-grouse (all ages combined) documented in various studies ranged from 38 to 60 percent (Schroeder

et al.

1999), and for females 55 to 75 percent (Schroeder 1997; Schroeder

et al.

1999). Survival rates are high compared with other prairie grouse species (Schroeder

et al.

1999). Higher female survival rates account for a female-biased sex ratio in adult birds (Schroeder 1997; Johnsgard 2002). Although seasonal patterns of mortality have not been thoroughly examined, over-winter mortality is low (Connelly

et al.

2004).

Range and Distribution

Prior to settlement of the western North America by European immigrants in the 19th century, greater sage-grouse lived in 13 States and 3 Canadian provinces—Washington, Oregon, California, Nevada, Idaho, Montana, Wyoming, Colorado, Utah, South Dakota, North Dakota, Nebraska, Arizona, British Columbia, Alberta, and Saskatchewan (Schroeder

et al.

1999; Young

et al.

2000; Schroeder

et al.

2004). Sagebrush habitats that potentially supported sage-grouse occurred over approximately 1,200,483 km2 (463,509 mi2) before 1800 (Schroeder

et al.

2004). 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. Sage-grouse have been extirpated from Nebraska, British Columbia, and possibly Arizona (Schroeder

et al.

1999; Young

et al.

2000; Schroeder

et al.

2004). Current distribution of the greater sage-grouse is estimated at 668,412 km2 (258,075 mi2) or 56 percent of the potential pre-settlement distribution (Schroeder

et al.

2004; Connelly

et al.

2004). The vast majority of the current distribution of the greater sage-grouse is within the United States.

Estimates of current total sage-grouse abundance vary, but are all much lower than the historical estimates of a million or more birds. Braun (1998) estimated that the 1998 rangewide spring population numbered about 142,000 sage-grouse, derived from numbers of males counted on leks. The Service estimated the rangewide abundance of sage-grouse in 2000 was at least 100,000 (taken from Braun (1998)) and up to 500,000 birds (based on harvest data from Idaho, Montana, Oregon and Wyoming, with the assumption that 10 percent of the population is typically harvested) (65 FR 51578). Survey intensity has increased markedly in recent years and, in 2003, more than 50,000 males were counted on leks (Connelly

et al.

2004). Therefore, Connelly

et al.

(2004) concluded that rangewide population numbers in 2003 were likely much greater than the 142,000 estimated in 1998 but was unable to generate a rangewide population estimate. Sampling methods used across the range of the sage-grouse differ, resulting in too much variation to reliably estimate sage-grouse numbers (Connelly

et al.

2004). Since neither pre-settlement nor current numbers of sage-grouse are known with complete precision, the actual rate and extent of decline cannot be exactly estimated.

Periods of historical decline in sage-grouse abundance occurred from the late 1800s to the early-1900s (Hornaday 1916; Crawford 1982; Drut 1994; Washington Department of Fish and Wildlife 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; Braun 1998). State wildlife agencies were sufficiently concerned with the decline in the 1920s and 1930s that many closed their hunting seasons and others significantly reduced bag limits and season lengths (Braun 1998) as a precautionary measure.

Following review of published literature and anecdotal reports, Connelly

et al.

(2004) concluded that the abundance and distribution of sage-grouse have declined from pre-settlement numbers to present abundance. Most of the historic population changes were the result of local extirpations, which has been inferred from a 44 percent reduction in sage-grouse distribution described by Schroeder

et al.

2004 (Connelly

et al.

2004). In an analysis of lek counts, Connelly

et al.

(2004) found substantial declines from 1965 through 2003. Average declines were 2 percent of the population per year from 1965 to 2003. The decline was more dramatic from 1965 through 1985, with an average annual change of 3.5 percent. Sage-grouse population numbers in the late 1960s and early 1970s were likely two to three times greater than current numbers (Connelly

et al.

2004). However, the rate of decline rangewide slowed from 1986 to 2003 to 0.37 percent annually, and some populations increased (Connelly

et al.

2004).

According to Connelly

et al.

(2004), of 41 populations delineated rangewide on geographical, not political boundaries, 5 have been extirpated and 14 are at high risk of extirpation due to small numbers (only one active lek). Twelve additional

populations also have small numbers (7 to 18 known active leks), and 9 of those are declining at a statistically significant rate. However, the remaining 10 populations contained the majority (92 percent) of the known active leks and were distributed across the current range. Five of these populations were so large and expansive that they were divided into 24 subpopulations to facilitate the analysis for a rangewide assessment (Connelly

et al.

2004).

Habitat

Sagebrush is the most widespread vegetation in the intermountain lowlands in the western United States (West and Young 2000). Scientists recognize many species and subspecies of sagebrush (Connelly

et al.

2004), each with unique habitat requirements and responses to perturbations (West and Young 2000). Sagebrush species and subspecies occurrence in an area is dictated by local soil type, soil moisture, and climatic conditions (West 1983; West and Young 2000), and the degree of dominance by sagebrush varies with local site conditions and disturbance history. Plant associations, typically defined by perennial grasses, further define distinctive sagebrush communities (Miller and Eddleman 2000; Connelly

et al.

2004), and are influenced by topography, elevation, precipitation and soil type.

All species of sagebrush produce large ephemeral leaves in the spring, which persist until soil moisture stress develops in the summer. Most species also produce smaller, over-wintering leaves in the late spring that last through summer and winter. Sagebrush have fibrous, tap root systems, which allow the plants to draw surface soil moisture, but also access water deep within the soil profile when surface water is limiting (West and Young 2000). Most sagebrush flower in the fall. However, during years of drought or other moisture stress, flowering may not occur. Although seed viability and germination are high, seed dispersal is limited. Additionally, for unknown reasons, sagebrush seeds do not persist in seed banks beyond the year of their production (West and Young 2000).

Sagebrush are long-lived, with plants of some species surviving up to 150 years (West 1983). They produce allelopathic chemicals that reduce seed germination, seedling growth and root respiration of competing plant species and inhibit the activity of soil microbes and nitrogen fixation. Sagebrush has resistance to environmental extremes, with the exception of fire and occasionally defoliating insects (

e.g.

, the webworm (

Aroga

spp.; West 1983)). Most species of sagebrush are killed by fire (Miller and Eddleman 2000; West 1983; West and Young 2000). Natural sagebrush re-colonization in burned areas depends on the presence of adjacent live plants for a seed source or on the seed bank, if present (Miller and Eddleman 2000).

Sagebrush is typically divided into two groups, big sagebrush and low sagebrush, based on their affinities for different soil types (West and Young 2000). Big sagebrush species and subspecies are limited to coarse-textured and/or well-drained sediments, whereas low sagebrush subspecies typically occur where erosion has exposed clay or calcified soil horizons (West 1983; West and Young 2000). Reflecting these soil differences, big sagebrush will die if surfaces are saturated long enough to create anaerobic conditions for 2 to 3 days (West and Young 2000). Some of the low sagebrush are more tolerant of occasionally supersaturated soils, and many low sage sites are partially flooded during spring snowmelt. None of the sagebrush taxa tolerate soils with high salinity (West and Young 2000). Both groups of sagebrush are used by sage-grouse.

The response of sagebrush and sagebrush ecosystems to natural and human-influenced disturbances varies based on the species of sagebrush and its understory component, as well as abiotic factors such as soil types and precipitation. For example, mountain big sagebrush can generally recover more quickly and robustly following disturbance than Wyoming big sagebrush (Miller and Eddleman 2000), likely due to its occurrence on moist, well drained soils, versus the very dry soils typical of Wyoming big sagebrush communities. Soil associations have also resulted in disproportionate levels of habitat conversion across different sagebrush communities. For example, basin big sage is found at lower elevations, in soils that retain moisture two to four weeks longer than in well drained, but dry and higher elevation soils typical of Wyoming big sagebrush locations. Therefore, sagebrush communities dominated by basin big sagebrush have been converted to agriculture more extensively than have communities on poorer soil sites (Winward 2004).

The effects of disturbance to sagebrush are not constant across the range of the sage-grouse. Connelly

et al.

(2004) presented sage-grouse population data by the described delineations of sagebrush ecosystems and communities (Miller and Eddleman 2000, from Kuchler's 1985 map; and West 1983). Unfortunately, information on impacts to the habitats has not been collected in a compatible manner, making analyses of these impacts specifically within each distinct ecosystem and community impossible. Therefore, while we acknowledge habitat differences across the greater sage-grouse range, we were unable to conduct our review at that level.

Discussion of Listing Factors

Section 4 of the Act (16 U.S.C. 1531) and implementing regulations at 50 CFR part 424 set forth procedures for adding species to the Federal endangered and threatened species list. 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. These factors and their application to the greater sage-grouse are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

Habitat Conversion

Sagebrush is estimated to have covered roughly 120 million ha (296 million ac; Schroeder

et al.

2004) in western North America, but millions of those hectares have been cultivated for the production of potatoes, wheat, and other crops (Schroeder

et al.

1999, 2000). Western rangelands were converted to agricultural lands on a large scale beginning with the series of Homestead Acts in the 1800s (Braun 1998, Hays

et al.

1998), especially where suitable deep soil terrain and water were available (Rogers 1964). Connelly

et al.

(2004) estimated that 24.9 million ha (61.5 million ac) within their assessment area for sage-grouse is now comprised of agricultural lands (note, not all of the species' total range is sagebrush habitat, and the assessment area is larger than the sage-grouse current distribution). Influences resulting from agricultural activities adjoining sagebrush habitats extend into those habitats, and include increased predation and reduced nest success due to predators associated with agriculture (Connelly

et al.

2004). Adding a 6.9 km (4.3 mi) buffer around agricultural areas (for the potential foraging distance of domestic cats and red foxes (

Vulpes vulpes

)), Connelly

et al.

(2004) estimated 115.2 million ha (284.7 million ac) (56 percent) within their assessment area for the greater sage-grouse is influenced by agriculture.

In some States, the loss of sagebrush shrub-steppe habitats through conversion to agricultural crops has been dramatic. This impact has been

especially apparent in the Columbia Basin of the Northwest and the Snake River Plain of Idaho (Schroeder

et al.

2004). Hironaka

et al.

(1983) estimated that 99 percent of basin big sagebrush (

A. t. tridentata

) habitat in the Snake River Plain has been converted to cropland. Prior to European immigrant settlement in the 19th century, Washington had an estimated 42 million ha (103.8 million ac) of shrub-steppe (Connelly

et al.

2004). Dobler (1994) estimated that approximately 60 percent of the original shrub-steppe habitat in Washington has been converted to primarily agricultural uses. In eastern Washington, land conversion to dryland farming occurred mostly between 1900 and the 1940s (Hays

et al.

1998) and then in the 1950s and 1960s large-scale irrigation projects (made possible through the construction of dams) reduced sage-grouse habitat even further (Hofmann 1991 in Hays

et al.

1998). Deep soils supporting shrub-steppe communities in Washington continue to be converted to agricultural uses (Vander Haegen

et al.

2000), resulting in habitat loss. In north central Oregon, approximately 2.6 million ha (6.4 million ac) of habitat were converted for agricultural purposes, essentially eliminating sage-grouse from this area (Willis

et al.

1993). More broadly, across the Interior Columbia Basin of southern Idaho, northern Utah, northern Nevada, eastern Oregon and Washington, approximately 6 million ha (14.8 million ac) of shrub-steppe habitat has been converted to agricultural crops (Altman and Holmes 2000).

Development of irrigation projects to support agricultural production, in some cases conjointly with hydroelectric dam construction, has resulted in additional sage-grouse habitat loss (Braun 1998). The reservoirs formed by these projects impacted native shrub-steppe habitat adjacent to the rivers in addition to supporting the irrigation and direct conversion of shrub-steppe lands to agriculture. 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). The creation of these reservoirs also inundated hundreds of kilometers of riparian habitats used by sage-grouse broods (Braun 1998). However, other small and isolated reclamation projects (4,000 to 8,000 ha [10,000 to 20,000 ac]) were responsible for three-fold localized increases in sage-grouse populations (Patterson 1952) by providing water in a semi-arid environment which provided additional insect and forb food resources (

e.g.

, Eden Reclamation Project in Wyoming). Shrub-steppe habitat continues to be converted for both dryland and irrigated crop production, albeit at much-reduced levels (65 FR 51578; Braun 1998).

Although conversion of shrub-steppe habitat to agricultural crops impacts sage-grouse through the loss of sagebrush on a broad scale, some studies report the use of agricultural crops (

e.g.

, alfalfa) by sage-grouse. When alfalfa fields and other croplands are adjacent to extant sagebrush habitat, sage-grouse have been observed feeding in these fields, especially during brood-rearing (Patterson 1952, Rogers 1964, Wallestad 1971, Connelly

et al.

1988, Fischer

et al.

1997). Connelly

et al.

(1988) reported seasonal movements of sage-grouse to agricultural crops as sagebrush habitats desiccated during the summer.

Sagebrush removal to increase herbaceous forage and grasses for domestic and wild ungulates is a common practice in sagebrush ecosystems (Connelly

et al.

2004). By the 1970s, over 2 million ha (5 million ac) of sagebrush had been mechanically treated, sprayed with herbicide, or burned (Crawford

et al.

2004). Braun (1998) concluded that since European settlement of western North America, all sagebrush habitats used by greater sage-grouse have been treated in some way to reduce shrub cover. The use of chemicals to control sagebrush was initiated in the 1940s and intensified in the 1960s and early 1970s (Braun 1987).

The extent to which mechanical and chemical removal or control of sagebrush currently occurs is not known, particularly with regard to private lands. However, the BLM has stated that with rare exceptions, they no longer are involved in actions that convert sagebrush to other habitat types, and that mechanical or chemical treatments in sagebrush habitat on BLM lands currently focus on improving the diversity of the native plant community, reducing conifer encroachment, or reducing the risk of a large wildfire (BLM 2004a).

Greater sage-grouse response to herbicide treatments depends on the extent to which forbs and sagebrush are killed. Chemical control of sagebrush has resulted in declines of sage-grouse breeding populations through the loss of live sagebrush cover (Connelly

et al.

2000a). Herbicide treatment also can result in sage-grouse emigration from affected areas (Connelly

et al.

2000a), and has been documented to have a negative effect on nesting, brood carrying capacity (Klebenow 1970), and winter shrub cover essential for food and thermal cover (Pyrah 1972 and Higby 1969 as cited in Connelly

et al.

2000a). Conversely, small treatments interspersed with non-treated sagebrush habitats did not affect sage-grouse use, presumably due to minimal effects on food or cover (Braun 1998). Also application of herbicides in early spring to reduce sagebrush cover may enhance some brood-rearing habitats by increasing the coverage of herbaceous plant foods (Autenrieth 1981).

Mechanical treatments are designed to either remove the aboveground portion of the sagebrush plant (mowing, roller chopping, and rotobeating), or to uproot the plant from the soil (grubbing, bulldozing, anchor chaining, cabling, railing, raking, and plowing; Connelly

et al.

2004). These treatments were begun in the 1930s and continued at relatively low levels to the late 1990s (Braun 1998). Mechanical treatments, if carefully designed and executed, can be beneficial to sage-grouse by improving herbaceous cover, forb production, and resprouting of sagebrush (Braun 1998). However, adverse effects also have been documented (Connelly

et al.

2000a). For example, in Montana, the number of breeding males declined by 73 percent after 16 percent of the 202 km

2

(78 mi

2

) study area was plowed (Swenson

et al.

1987). Mechanical treatments in blocks greater than 100 ha (247 ac), or of any size seeded with exotic grasses, degrade sage-grouse habitat by altering the structure and composition of the vegetative community (Braun 1998).

While many square miles of sagebrush habitat has been lost during the past 150 years to conversion of sagebrush habitat to agriculture, this conversion occurs at such relatively low levels today, that we do not consider it a threat to the greater sage-grouse on a rangewide basis.

Habitat Fragmentation

This section considers the various natural and anthropogenic forces that influence sage-grouse habitat and can result in habitat fragmentation. Habitat fragmentation is the separation or splitting apart of previously contiguous, functional habitat components of a species. Fragmentation can result from direct habitat losses that leave the remaining habitat in non-contiguous patches, or from alteration of habitat areas that render the altered patches unusable to a species (

i.e.

, functional habitat loss). Functional habitat losses include disturbances that change a habitat's successional state or remove one or more habitat functions, physical barriers that preclude use of otherwise suitable areas, and activities that prevent animals from using suitable habitats patches due to behavioral avoidance.

Sagebrush communities exhibit a high degree of variation in their resistance and resilience to change, beyond natural variation. Resistance (the ability to withstand disturbing forces without changing) and resilience (the ability to recover once altered) generally increase with increasing moisture and decreasing temperatures, and can also be linked to soil characteristics (Connelly

et al.

2004). However, most extant sagebrush habitat has been altered since European immigrant settlement of the West (Baker

et al.

1976; Braun 1998; Knick

et al.

2003; Connelly

et al.

2004), and sagebrush habitat continues to be fragmented and lost (Knick

et al.

2003) through the factors described below. The cumulative effects of habitat fragmentation have not been quantified over the range of sagebrush and most fragmentation cannot be attributed to specific land uses (Knick

et al.

2003).

Fragmentation of sagebrush habitats has been cited as a primary cause of the decline of sage-grouse populations since the species requires large expanses of contiguous sagebrush (Patterson 1952; Connelly and Braun 1997; Braun 1998; Johnson and Braun 1999; Connelly

et al.

2000a; Miller and Eddleman 2000; Schroeder and Baydack 2001; Johnsgard 2002; Aldridge and Brigham 2003; Beck

et al.

2003; Pedersen

et al.

2003; Connelly

et al.

2004; Schroeder

et al.

2004). However, there is a lack of data to assess how fragmentation influences specific greater sage-grouse life history parameters such as productivity, density, and home range. While sage-grouse are dependent on interconnected expanses of sagebrush (Patterson 1952; Connelly

et al.

2004), data are not available regarding minimum sagebrush patch sizes to support populations of sage-grouse. Estimating the impact of habitat fragmentation on sage-grouse is complicated by time lags in response to habitat changes, particularly since these long-lived birds will continue to return to altered breeding areas (leks, nesting areas, and early brood-rearing areas) due to strong site fidelity despite nesting or productivity failures (Wiens and Rotenberry 1985).

Powerlines

Power grids were first constructed in the United States in the late 1800s. The public demand for electricity has grown as human population and industrial activities have expanded (Manville 2002), resulting in more than 804,500 km (500,000 mi) of transmission lines (lines carrying ≥ 115,000 volts/115kV) by 2002 within the United States (Manville 2002). A similar estimate is not available for distribution lines (lines carrying ≤ 69,000 volts/69kV), and we are not aware of data for Canada. Within their analysis area (

i.e.

, the pre-European settlement distribution of greater sage-grouse, including Canada, plus a 50-km (31.3-mi) buffer (buffer is to allow for external factors that may have contributed to current trends in populations or habitats)), Connelly

et al.

(2004) state there is a minimum of 15,296 km

2

(5,904 mi

2

) of land (less than 1 percent of their assessment area) in transmission powerline corridors, but could provide no estimate of the density of distribution lines in their assessment area.

Powerlines can directly affect greater sage-grouse by posing a collision and electrocution hazard (Braun 1998; Connelly

et al.

2000a), and can have indirect effects by increasing predation (Connelly

et al.

2004), fragmenting habitat (Braun 1998), and facilitating the invasion of exotic annual plants (Knick

et al.

2003; Connelly

et al.

2004). In 1939, Borell reported the deaths of 3 adult sage-grouse as a result of colliding with a telegraph line in Utah (Borell 1939). Both Braun (1998) and Connelly

et al.

(2000a) report that sage-grouse collisions with powerlines occur, although no specific instances were presented. Other than an unpublished observation reported by Aldridge and Brigham (2003), we were unable to find documentations of other collisions and/or electrocutions of sage-grouse resulting from powerlines.

In areas where the vegetation is low and the terrain relatively flat, power poles provide an attractive hunting and roosting perch, as well as nesting stratum for many species of raptors (Steenhof

et al.

1993; Connelly

et al.

2000a; Manville 2002; Vander Haegen

et al.

2002). Power poles increase a raptor's range of vision, allow for greater speed during attacks on prey, and serve as territorial markers (Steenhof

et al.

1993; Manville 2002). Raptors may actively seek out power poles where natural perches are limited. For example, within one year of construction of a 596-km (372.5-mi) transmission line in southern Idaho and Oregon, raptors and common ravens (

Corvus corax

) began nesting on the supporting poles (Steenhof

et al.

1993). Within 10 years of construction, 133 pairs of raptors and ravens were nesting along this stretch (Steenhof

et al.

1993). The increased abundance of raptors and corvids within occupied sage-grouse habitats can result in increased predation. Ellis (1985) reported that golden eagle predation on sage-grouse on leks increased from 26 to 73 percent of the total predation after completion of a transmission line within 200 m (220 yd) of an active sage-grouse lek in northeastern Utah. The lek was eventually abandoned, and Ellis (1985) concluded that the presence of the powerline resulted in changes in sage-grouse dispersal patterns and fragmentation of the habitat. Leks within 0.4 km (0.25 mi) of new powerlines constructed for coalbed methane development in the Powder River Basin of Wyoming had significantly lower growth rates, as measured by recruitment of new males onto the lek, compared to leks further from these lines, which was presumed to be the result of increased raptor predation (Braun

et al.

2002). Within their analysis area, Connelly

et al.

(2004) estimated that the area potentially influenced by additional perches for corvids and raptors provided by powerlines, assuming a 5 to 6.9-km (3.1 to 4.3-mi) radius buffer around the perches based on the average foraging distance of these predators, was 672,644 to 837,390 km

2

(259,641 to 323,317 mi

2

), or 32 to 40 percent of their assessment area. The actual impact on the area would depend on corvid and raptor densities within the area. The presence of a powerline may fragment sage-grouse habitats even if raptors are not present. Braun (1998; unpublished data) found that use of otherwise suitable habitat by sage-grouse near powerlines increased as distance from the powerline increased for up to 600 m (660 yd) and based on that unpublished data reported that the presence of powerlines may limit sage-grouse use within 1 km (0.6 mi) in otherwise suitable habitat.

Linear corridors through sagebrush habitats can facilitate the spread of invasive species, such as cheatgrass (

Bromus tectorum

) (Gelbard and Belnap 2003; Knick

et al.

2003; Connelly

et al.

2004). However, we were unable to find any information regarding the amount of invasive species incursion as a result of powerline construction.

Powerlines are common to nearly every type of anthropogenic habitat use, except perhaps some forms of agricultural development (

e.g.

, livestock grazing) and fire. Although we were unable to find an estimate of all future proposed powerlines within currently occupied sage-grouse habitats, we anticipate that powerlines will increase, particularly given the increasing development of energy resources and urban areas. For example, up to 8,579 km (5,311 mi) of new powerlines are predicted for the development of the Powder River Basin coal-bed methane field in northeastern Wyoming (BLM 2003a) in addition to the approximately 9,656 km (6,000 mi) already constructed in that area. Although raptors associated

with powerlines may negatively impact individual greater sage-grouse and habitats, we could find no information regarding the effect of this impact on a rangewide basis.

Communication Towers

Within sage-grouse habitats, 9,510 new communication towers have been constructed within recent years (Connelly

et al.

2004). While millions of birds are killed annually in the United States through collisions with communication towers and their associated structures (guy wires, lights, etc.; Manville 2002), most documented mortalities are of migratory songbirds. We were unable to determine if any sage-grouse mortalities occur as a result of collision with communication towers or their supporting structures, as most towers are not monitored and those that are lie outside the range of the species (Shire

et al.

2000; Kerlinger 2000). However, communication towers also provide perches for corvids and raptors (Steenhof

et al.

1993; Connelly

et al.

2004). We could find no information regarding the potential impacts of communication towers to the greater sage-grouse on a rangewide basis.

Fences

Fences are used to delineate property boundaries and for livestock management (Braun 1998; Connelly

et al.

2000a). The effects of fencing on sage-grouse include direct mortality through collisions, creation of predator (raptor) perch sites, the potential creation of a predator corridor along fences (particularly if a road is maintained next to the fence), incursion of exotic species along the fencing corridor, and habitat fragmentation (Call and Maser 1985; Braun 1998; Connelly

et al.

2000a; Beck

et al.

2003; Knick

et al.

2003; Connelly

et al.

2004).

Sage-grouse frequently fly low and fast across sagebrush flats and new fences can create a collision hazard (Call and Maser 1985). Thirty-six carcasses of sage-grouse were found near Randolph, Utah, along a 3.2 km (2 mi) fence within three months of its construction (Call and Maser 1985). Twenty-one incidents of mortality through fence collisions near Pinedale, Wyoming, were reported in 2003 to the BLM (Connelly

et al.

2004). Fence collisions continue to be identified as a source of mortality (Braun 1998; Connelly

et al.

2000a; Oyler-McCance

et al.

2001; Connelly

et al.

2004), although effects on populations are not understood. Fence posts also create perching places for raptors and corvids, which may increase their ability to prey on sage-grouse (Braun 1998; Connelly

et al.

2000b; Oyler-McCance

et al.

2001; Connelly

et al.

2004). We anticipate that the effect on sage-grouse populations through the creation of new raptor perches and predator corridors into sagebrush habitats are similar to that of powerlines discussed previously (Braun 1998; Connelly

et al.

2004). Fences and their associated roads also facilitate the spread of invasive plant species that replace sagebrush plants upon which sage-grouse depend (Braun 1998; Connelly

et al.

2000a; Gelbard and Belnap 2003; Connelly

et al.

2004). Greater sage-grouse 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). More than 1,000 km (625 mi) of fences were constructed annually in sagebrush habitats from 1996 through 2002, mostly in Montana, Nevada, Oregon and Wyoming (Connelly

et al.

2004). Over 51,000 km (31,690 mi) of fences were constructed on BLM lands supporting sage-grouse populations between 1962 and 1997 (Connelly

et al.

2000a). However, some of the new 1-3 wire fencing being erected across the range may pose less of a collision risk to sage grouse than woven fences.

Roads and Railroads

Impacts from roads may include direct habitat loss, direct mortality, create barriers to migration corridors or seasonal habitats, facilitation of predators and spread of invasive vegetative species, and other indirect influences such as noise (Forman and Alexander 1998). Interstates and major paved roads cover approximately 14,272 km

2

(22,835 mi

2

), less then 1 percent of their assessment area (Connelly

et al.

2004). Secondary paved road densities within this area range to greater than 2 km/km

2

(3.24 mi/mi

2

). Sage-grouse mortality resulting from collisions with vehicles does occur (Patterson 1952), but mortalities are typically not monitored or recorded. Therefore, we are unable to determine the importance of this factor on sage-grouse populations. Data regarding how roads affect seasonal habitat availability for individual sage-grouse populations by creating barriers and the ability of sage-grouse to reach these areas were not available. Road development within Gunnison sage-grouse habitats precluded movement of local populations between the resultant patches, presumably to minimize their exposure to predation (Oyler-McCance

et al.

2001).

Roads can provide corridors for predators to move into previously unoccupied areas. For some mammalian species, dispersal along roads has greatly increased their distribution (Forman and Alexander 1998; Forman 2000). Corvids also use linear features such as primary and secondary roads as travel routes, expanding their movements into previously unused regions (Connelly

et al.

2000b; Aldridge and Brigham 2003; Connelly

et al.

2004). In an analysis of anthropogenic impacts, Connelly

et al.

(2004) reported that at least 58 percent of their analysis area has a high or medium presence of corvids, known sage-grouse nest and chick predators (Schroeder and Baydack 2001). We have no information on the extent to which corvids prey on sage-grouse chicks and eggs. Additionally, highway rest areas provide a source of food and perches for corvids and raptors, and facilitate their movements into surrounding areas (Connelly

et al.

2004). It has not been documented that sage-grouse populations are affected by predators using roads as corridors into sagebrush habitats.

The presence of roads also increases human access and their resulting disturbance effects in remote areas (Forman and Alexander 1998; Forman 2000; Connelly

et al.

2004). Increases in legal and illegal hunting activities resulting from the use of roads built into sagebrush habitats have been documented (Patterson 1952; Connelly

et al.

2004). However, the actual current effect of these increased activities on sage-grouse populations has not been determined. Roads may also facilitate access for habitat treatments (Connelly

et al.

2004), resulting in subsequent direct habitat losses. New roads are being constructed to support development activities within the greater sage-grouse extant range. For example, in the Powder River Basin of Wyoming, up to 28,572 km (17,754 mi) of roads to support coalbed methane development are proposed (BLM 2003a).

The expansion of road networks has been documented to contribute to exotic plant invasions via introduced roadfill, vehicle transport, and road maintenance activities (Forman and Alexander 1998; Forman 2000; Gelbard and Belnap 2003; Knick

et al.

2003; Connelly

et al.

2004). Invasive species are not limited to roadsides (or verges), but have also encroached into the surrounding habitats (Forman and Alexander 1998; Forman 2000; Gelbard and Belnap 2003). In their study of roads on the Colorado Plateau of southern Utah, Gelbard and Belnap (2003) found that improving unpaved four-wheel drive roads to paved roads resulted in increased cover of exotic plant species within the interior of adjacent vegetative

communities. This effect was associated with road construction and maintenance activities and vehicle traffic, and not with differences in site characteristics. The incursion of exotic plants into native sagebrush systems can negatively affect greater sage-grouse through habitat losses and conversions (see further discussion below).

Additional indirect effects of roads may result from birds' behavioral avoidance of road areas because of noise, visual disturbance, pollutants, and predators moving along a road. The absence of screening vegetation in arid and semiarid regions further exacerbates the problem (Suter 1978). Male sage-grouse depend on acoustical signals to attract females to leks (Gibson and Bradbury 1985; Gratson 1993). If noise interferes with mating displays, and thereby female attendance, younger males will not be drawn to the lek and eventually leks will become inactive (Amstrup and Phillips 1977; Braun 1986). Dust from roads and exposed roadsides can damage vegetation through interference with photosynthetic activities; the actual amount of potential damage depends on winds, wind direction, the type of surrounding vegetation and topography (Forman and Alexander 1998). Chemicals used for road maintenance, particularly in areas with snowy or icy precipitation, can affect the composition of roadside vegetation (Forman and Alexander 1998). We were unable to find any data relating these potential effects to impacts on sage-grouse population parameters.

In a study on the Pinedale Anticline in Wyoming, sage-grouse hens that bred on leks within 3 km (1.9 mi) of roads associated with oil and gas development traveled twice as far to nest as did hens bred on leks greater than 3 km (1.9 mi) from roads. Nest initiation rates for hens bred on leks “close” to roads were also lower (50 vs 65 percent) affecting population recruitment (33 vs. 44 percent) (Lyon 2000; Lyon and Anderson 2003). Lyon and Anderson (2003) suggested that roads may be the primary impact of oil and gas development to sage-grouse, due to their persistence and continued use even after drilling and production have ceased. Braun

et al.

(2002) suggested that daily vehicular traffic along road networks for oil wells can impact sage-grouse breeding activities based on lek abandonment patterns. In a study of 804 leks within 100 km (62.5 mi) of Interstate 80 in southern Wyoming and northeastern Utah, Connelly

et al.

(2004) found that there were no leks within 2 km (1.25 mi) of the interstate and only 9 leks were found between 2 and 4 km (1.25 and 2.5 mi) along this same highway. The number of active leks increased with increasing distance from the interstate. Lek persistence and activity relative to distance from the interstate were also measured. The distance of a lek from the interstate was a significant predictor of lek activity, with leks further from the interstate more likely to be active. An analysis of long-term changes in populations between 1970 and 2003 showed that leks closest to the interstate declined at a greater rate than those further away (Connelly

et al.

2004). What is not clear from these studies is what specific factor relative to roads (

e.g.

, noise, changes in vegetation, etc.) sage-grouse are responding to, and Connelly

et al.

(2004) caution that they have not included other potential sources of indirect disturbance (

e.g.

, powerlines) in their analyses.

Railroads presumably have the same potential impacts to sage-grouse as do roads since they create linear corridors within sagebrush habitats. Railways were primarily responsible for the initial spread of cheatgrass in the intermountain region (Connelly

et al.

2004). Cheatgrass, an exotic species that is unsuitable as sage-grouse habitat, readily invaded the disturbed soils adjacent to railroads, being distributed by trains and the cattle they transported. Fires created by trains facilitated the spread of cheatgrass into adjacent areas. Railroads cover 137 km

2

(53 mi

2

) of the sage-grouse in Connelly

et al.

's (2004) assessment area, but are estimated to influence an area of 183,915 km

2

(71,000 mi

2

), assuming a 3 km (1.9 mi) zone of influence (9 percent of their assessment area). Avian collisions with trains occur, although no estimates of mortality rates are documented in the literature (Erickson

et al.

2001).

The effects of infrastructure, particularly as related to energy development and urbanization, were identified by some members of the expert panel as an important factor contributing to the extinction risk for greater sage-grouse, particularly in the eastern part of the species range (Montana, Wyoming and Colorado). Across the entire range of the greater sage-grouse, infrastructure ranked second as an extinction risk factor by the expert panel.

Grazing

Bison, antelope and other ungulates grazed lands occupied by sage-grouse prior to European immigrant settlement of the western United States in the mid to late 1800s. With settlement, from 1870 to the early 1900s, the numbers of cattle, sheep, and horses rapidly increased, peaking at the turn of the century (Oliphant 1968, Young

et al.

1976) with an estimated 26 million cattle and 20 million sheep in the West (Wilkenson 1992). Livestock grazing is the most widespread type of land use across the sagebrush biome (Connelly

et al.

2004); almost all sagebrush areas are managed for livestock grazing (Knick

et al.

2003). Cattle and sheep animal unit months (AUMs; the amount of forage required to feed one cow with calf, one horse, five sheep, or five goats for one month) on all Federal land have declined since the early 1900s (Laycock

et al.

1996). By the 1940s AUMs on all Federal lands were estimated to be 14.6 million, increasing to 16.5 million in the 1950s, and gradually declining to 10.2 million by the 1990s (Miller and Eddleman 2000). As of 2003, active AUMs for BLM lands in States where sage-grouse occur totaled about 10.1 million (BLM 2003b). Most of the 78.3 million acres of BLM-administered land within the current range of the greater sage-grouse are open to livestock grazing (BLM 2004a). Knick

et al.

(2003) state that excessive grazing by domestic livestock during the late 1800s and early 1900s, along with severe drought, significantly impacted sagebrush ecosystems. Long-term effects from this overgrazing, including changes in plant communities and soils persist today.

Few studies have directly addressed the effect of livestock grazing on sage-grouse (Beck and Mitchell 2000, Wamboldt

et al.

2002, Crawford

et al.

2004), and there is little direct experimental evidence linking grazing practices to sage-grouse population levels (Braun 1987, Connelly and Braun 1997). Native herbivores, such as pronghorn antelope (

Antilocarpo americana

), were present in the sagebrush steppe region prior to European settlement of western States (Miller

et al.

1994), and sage-grouse co-evolved with these animals. However, many areas of sagebrush-steppe did not support herds of large ungulates, as large native herbivores disappeared 12,000 years before present (Knick

et al.

2003). Therefore, native vegetation communities within the sagebrush ecosystem developed in the absence of significant grazing presence (Knick

et al.

2003).

It has been demonstrated that the reduction of grass heights due to livestock grazing of sage-grouse nesting and brood-rearing areas negatively affects nesting success by reducing cover necessary for predator avoidance (Gregg

et al.

1994; Delong

et al.

1995; Connelly

et al.

2000a). In addition, livestock consumption of forbs may reduce food availability for sage-grouse.

This is particularly important for pre-laying hens, as forbs provide essential calcium, phosphorus, and protein. A hen's nutritional condition affects nest initiation rate, clutch size, and subsequent reproductive success (Connelly

et al.

2000a). This information indicates that grazing by livestock could reduce the suitability of breeding and brood-rearing habitat, subsequently negatively affecting sage-grouse populations (Braun 1987, Dobkin 1995, 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 the proportion of shrub, grass, and forb components in the affected area, and an increased invasion of exotic plant species that do not provide suitable habitat for sage-grouse (Miller and Eddleman 2000). Hulet (1983, as cited in Connelly

et al.

2000a) found that heavy grazing could lead to increases in ground squirrels that depredate sage-grouse nests. Thus, important factors of livestock operations related to impacts on sage-grouse include stocking levels, season of use, and utilization levels.

Other consequences of grazing include several related to livestock trampling. Outright nest destruction by livestock trampling does occur and the presence of livestock can cause sage-grouse to abandon their nests (Rasmussen and Griner 1938, Patterson 1952, Call and Maser 1985, Crawford

et al.

2004). Call and Maser (1985) indicate that forced movements of cattle and sheep could have significant effects on nesting hens and young broods caught in the path of these drives. Livestock may also trample sagebrush seedlings thereby removing a source of future sage-grouse food and cover (Connelly

et al.

2000a), and trampling of soil by livestock can reduce or eliminate biological soil crusts making these areas susceptible to cheatgrass invasion (Mack 1981 as cited in Miller and Eddleman 2000; Young and Allen 1997; Forman and Alexander 1998).

Livestock grazing may also compete directly with sage-grouse for rangeland resources. Cattle are grazers, feeding mostly on grasses, but they will make seasonal use of forbs and browse species like sagebrush (Vallentine 2001). Domestic sheep are intermediate feeders making high use of forbs, but also use a large volume of grass and browse species like sagebrush (Vallentine 2001). Pedersen

et al.

(2003) documented sheep consumption of rangeland forbs in areas where sage-grouse occur. The effects of direct competition between livestock and sage-grouse 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 sage-grouse in Alberta, results in a reduction of forbs and grasses available to sage-grouse chicks, thereby affecting chick survival.

Some effects of livestock grazing may have positive consequences for sage-grouse. Evans (1986) found that sage-grouse used grazed meadows significantly more during late summer than ungrazed meadows because grazing had stimulated the regrowth of forbs. Klebenow (1981) noted that sage-grouse sought out and used openings in meadows created by cattle grazing in northern Nevada. Finally both sheep and goats have been used to control invasive weeds (Mosely 1996 as cited in Connelly

et al.

2004; Olson and Wallander 2001; Merritt

et al.

2001) and woody plant encroachment (Riggs and Urness 1989) in sage-grouse habitat.

Although there are few studies which directly examine the effects of livestock grazing on greater sage-grouse, and no studies on a rangewide scale, the expert panel ranked grazing as a potential extinction risk factor. This ranking incorporates not only the direct effects of grazing, but all associated activities, such as vegetation management, fencing, overuse of riparian habitats by domestic livestock, etc. The expert panel also noted that the recovery of greater sage-grouse populations from the 1930s to the 1950s occurred during a period of a reduction in livestock grazing as well as a change in weather resulting in wetter conditions. However, the panel also noted that proper grazing management may be a beneficial tool for enhancing greater sage-grouse habitats where maintenance and enhancement of these habitats is identified as an objective, although this has not been rigorously tested.

Free-roaming horses and burros have been a component of sagebrush and other arid communities since they were brought to North America at the end of the 16th century (Wagner 1983; Beever 2003). About 31,000 wild horses occur in 10 western States, with herd sizes being largest in States with the most extensive sagebrush cover (Nevada, Wyoming, and Oregon; Connelly

et al.

2004). Burros occur in five western States, with about 5,000 of these present (Connelly

et al.

2004). Due to physiological differences, a horse consumes 20 to 65 percent more forage than would a cow of equivalent body mass (Wagner 1983; Menard

et al.

2002). We are unaware of any studies that directly address the impact of wild horses or burros on sagebrush and sage-grouse. However some authors have suggested that wild horses could negatively impact important meadow and spring brood-rearing habitats used by sage-grouse (Crawford

et al.

2004; Connelly

et al.

2004). Other impacts from wild horse grazing may be similar to the impacts resulting from domestic livestock in sagebrush habitats, but these have not been documented.

Sagebrush removal to increase herbaceous forage and grasses for domestic and wild ungulates is a common practice in sagebrush ecosystems (Connelly

et al.

2004). Removal from chemical and mechanical means has been discussed previously. The elimination of sagebrush is usually followed with rangeland seedings to improve forage for livestock grazing operations (Knick

et al.

2003; Connelly

et al.

2004). Large expanses of sagebrush have been removed and reseeded with non-native grasses, such as crested wheatgrass (

Agropyron cristatum

), to increase forage production on public lands (Shane

et al.

1983, cited in Knick

et al.

2003; Connelly

et al.

2004). These treatments had the effect of reducing or eliminating many native grasses and forbs present prior to the seedings. Sage-grouse are affected indirectly through the loss of native forbs that serve as food and the loss of native grasses that provide concealment or hiding cover within the understories of the former sagebrush stands (Connelly

et al.

2004). BLM reports that they no longer implement actions that result in removing large expanses of sagebrush and reseeding with non-native grasses (BLM 2004a).

Water developments for the benefit of livestock on public lands are common (Connelly

et al.

2004). Development of springs and other water sources to support livestock in upland shrub-steppe habitats can artificially concentrate domestic and wild ungulates in important sage-grouse habitats, thereby exacerbating grazing impacts in those areas through vegetation trampling, etc. (Braun 1998). Diverting the water sources has the secondary effect of changing the habitat present at the water source before diversion. This could result in the loss of either riparian or wet meadow habitat important to sage-grouse as sources of forbs or insects.

Mining

Development of mines within the distribution of the sage-grouse began before 1900 (Robbins and Ward 1994,

cited in Braun 1998). Surface mining for any mineral resource (coal, uranium, copper, bentonite, gypsum, oil shale, phosphate, limestone, gravel, etc.) will result in direct habitat loss for sage-grouse if the mining occurs in occupied sagebrush habitats. Direct loss of sage-grouse habitat can also occur if the overburden and/or topsoil resulting from mining activities are stored in sagebrush habitats. The actual effect of this loss depends on the quality, amount, and type of habitat disturbed, the scale of the disturbance, and if non-breeding habitat is affected, the availability of adjacent habitats (Proctor

et al.

1983; Remington and Braun 1991). Sage-grouse habitat losses from all sources of mining have occurred in Utah (Beck

et al.

2003), Colorado (Braun 1986), and Wyoming (Hayden-Wing Associates 1983), but the actual amount of habitat loss has not been tabulated. Sagebrush habitat has also been lost to mining in other states within the range of sage-grouse although reliable estimates of the amount of loss are not available.

Mined land reclamation is required by either the Federal or State governments in the greater sage-grouse states and Canada (Smyth and Dearden 1998). Due to the relatively recent nature of federal coal and Canadian regulation (27 and 41 years, respectively; Smyth and Dearden 1998) there is limited long-term monitoring data. The laws generally allow for a change in post-mining land use from pre-mining conditions, and restoration of pre-mining sagebrush habitat may not occur if the surface owner determines an alternative habitat type is preferable. However, Federal coal reclamation requires restoration of diversity and density standards if the private landowner agrees. Early efforts to restore sage-grouse habitats on mined lands focused on creating artificial leks, which was largely unsuccessful (Tate

et al.

1979; Proctor

et al.

1983). Most efforts now rely on seasonal restrictions for lek destruction and restoration of sagebrush habitats (Proctor

et al.

1983; Parrish and Anderson 1994). Regulation of non-coal mining in the United States is at the discretion of the individual States, and may or may not include wildlife habitat restoration as a criterion (Pat Deibert, U.S. Fish and Wildlife Service, pers. comm. 2004).

New vegetation types including exotic species may become established on mined areas (Moore and Mills 1977), altering their suitability for sage-grouse. Temporary habitat loss can stem from intentional planting to minimize erosion or for nurse crops (those crops planted to create suitable microhabitat conditions for the desired vegetative species). The length of this temporary conversion depends on the life of the mine, the success of reclamation, and whether or not reclamation is concurrent with mining disturbance. If reclamation plans call for the permanent conversion of the mined area to a different habitat type (

e.g.

, agriculture) the habitat loss becomes permanent. Invasive exotic plants may also establish on the disturbed surfaces. Removal of the overburden and target mineral may result in changes in topography, subsequently resulting in changes in microclimates and microhabitats (Moore and Mills 1977). Significant topographical changes can affect the ability to successfully restore the mined area to pre-existing vegetative conditions (Moore and Mills 1977). Additional habitat losses can occur if supporting infrastructure, such as roads, railroads, utility corridors, etc., become permanent landscape features after mining and reclamation are completed (Moore and Mills 1977).

In Wyoming and Montana an estimated 38,833 ha (96,000 ac) of disturbed Federal and non-Federal surface are associated with existing coal mining operations (Kermit Witherbee, Bureau of Land Management, pers. comm. 2004). Over the next ten years, it has been estimated that approximately 20,243 ha (50,000 ac) will be disturbed for coal mining activities. This is less than 1 percent of the Connelly

et al.

(2004) assessment area. Of that, 14,170 ha (35,000 ac) should be reclaimed within the same time-period, resulting in a net annual disturbance of 607 ha (1,500 ac). The actual impact to sage-grouse may be longer, as it takes 15 to 30 years for sagebrush regeneration to usable conditions (Connelly and Braun 1997). There will likely be additional losses of sagebrush habitat in other states as a result of mining activities (all types) although we are unable to quantify this.

Mining infrastructure, such as roads, railroads, powerlines, etc., may impact sage-grouse, although those effects are not expected to be different than previously described. Presumably, direct habitat loss will not be as large from subsurface mining. However, the amount of supporting infrastructure and indirect effects may be similar as for surface mines (Thomas and Leistritz 1981). Other indirect effects from mining can include reduced air quality from gaseous emissions and fugitive dust, degradation of surface water quality and quantity, changes in vegetation, topography, land-use practices, and disturbance from noise, ground shock and human presence, and mortality from collision with mining equipment (Moore and Mills 1977; Brown and Clayton 2004). Gaseous emissions, created from the operation of heavy equipment, trains, etc., are usually quickly dissipated in the windy, open areas typical of sagebrush. Fugitive dust could affect local vegetative and insect resources through coating important respiratory surfaces. In extreme cases, plant photosynthesis may be restricted (Moore and Mills 1977). This may result in reduced food and cover resources for sage-grouse. Fugitive dust may also affect sage-grouse through direct irritation of mucus membranes and/or exposure to toxic minerals that are otherwise trapped in the soils (Moore and Mills 1977). Most large surface mines are required to control fugitive dust, so these impacts are probably limited.

Water quality can generally be reduced through increased sediment loads, leaching of toxic compounds or elements from exposed ore, waste rock and overburden, introduction of excess nutrients from blasting and fertilizers, or introduction of pathogens from septic systems and waste disposal associated with mining activity (Moore and Mills 1977). Contamination of water supplies through toxic elements can result in either direct mortality to wildlife, or long-term chronic health problems. Pathogens can also have a similar detrimental effect on wildlife. Water supplies may decline either through direct removal of wetlands from mining activity or reduction from use for fugitive dust suppression. Remaining wetlands may subsequently receive increased use from other wildlife or domestic livestock, resulting in habitat degradation. In Nevada, extensive de-watering of ground water results from open pit gold mining (Kevin Kritz, U.S. Fish and Wildlife Service, pers. comm. 2004). The actual impact of these effects on sage-grouse is unknown. Since sage-grouse do not require free water (Schroeder

et al.

1999), we anticipate that impacts to water quality from mining activities have minimal population-level effects. The possible exception is degradation of riparian areas, which could result in brood habitat loss.

If blasting is necessary for removal of overburden or the target mineral, ground shock may occur. The full effects of ground shock on wildlife are unknown, but given its temporary duration and localized impact area, impacts are considered minimal (Moore and Mills 1977). One possible exception is the repeated use of explosives during lekking or nesting, which could potentially result in nest and/or lek abandonment (Moore and Mills 1977).

We are unaware of any research on the impact of these factors to sage-grouse. Noise from mining activities may limit sage-grouse use of surrounding suitable habitat. In a study of sharp-tailed grouse (

Pedioecetes phasianellus

) leks in northeastern Wyoming, data suggested that noise from an adjacent coal mine adversely affected leks by masking vocalizations, which resulted in reduced female attendance and yearling recruitment (Amstrup and Phillips 1977). In that study, the authors found that mining noise was continuous across days and seasons, and did not dissipate as it traveled across the adjacent landscape. The effects on sage-grouse of noise from mining are unknown, but sage-grouse also depend on acoustical signals to attract females to leks (Gibson and Bradbury 1985; Gratson 1993). If noise does interfere with mating displays, and thereby female attendance, younger males will not attend the lek, and eventually leks will become inactive (Amstrup and Phillips 1977; Braun 1986).

Mining can also impact sage-grouse through the increased presence of human activity, either through avoidance of suitable habitat adjacent to mines or through collisions with vehicles associated with mining operations (Moore and Mills 1977; Brown and Clayton 2004). An increased human population in an area, as a result of mine extraction activities, may result in increased hunting pressure, both legal and poaching (Moore and Mills 1977). Although these effects have not been quantified on sage-grouse populations, the State of Wyoming requires coal operators to educate their employees about wildlife regulations when they are hired. Sage-grouse may also be at increased risk for collision with vehicles simply due to the increased traffic associated with mining activities and transport (Moore and Mills 1977; Brown and Clayton 2004). However, we were unable to find any information regarding increased mortality of sage-grouse near mines as a result of this effect.

We were only able to locate a few studies that specifically examined the effects of coal mining on greater sage-grouse (Tate

et al.

1979; Hayden-Wing Associates 1983; Braun 1986; Remington and Braun 1991; Brown and Clayton 2004). In a study in North Park, Colorado, overall population numbers of sage-grouse were not reduced, but there was a reduction in the number of males attending leks within 2 km (0.8 miles) of three coal mines, as well as a failure to recruit yearling males to these existing leks (Braun 1986; Remington and Braun 1991). New leks formed further from the mining disturbance (Remington and Braun 1991). Additionally, some leks adjacent to mine areas that had been abandoned at the onset of mining were re-established when mining activities ceased, suggesting disturbance rather than loss of habitat was the limiting factor. There was no decline in hen survival in a population of sage-grouse near large surface coal mines in northeastern Wyoming and nest success was apparently unaffected by the adjacent mining activity (Brown and Clayton 2004). However, the authors concluded that this population could only be sustained by aggressive land management to maintain suitable habitat, as the existing habitat will become fragmented by continued mining.

Braun (1998) concluded that surface coal mining and all associated activities have negative short-term impacts on sage-grouse numbers and habitats near the mines. Sage-grouse will reestablish on mined areas once mining has ceased, but there is no evidence that population levels will reach their previous size. Additionally, the time span for population re-establishment may be 20 to 30 years (Braun 1998). Hayden-Wing Associates (1983) concluded that the loss of one or two leks in a regional area from coal mining was likely not limiting to local populations in their study on the Caballo Rojo Mine in northeastern Wyoming. However, if several leks are affected, local population numbers may decline (Hayden-Wing Associates 1983).

Hard rock mining impacts greater sage-grouse at the local level. The expert panel identified hard rock mining as a threat of relatively low importance compared to other threats. The effect of hard rock mining, when considered independently of other threats to the species, is likely of relatively low importance to the status of the species range-wide.

Non-Renewable and Renewable Energy Development

Non-renewable energy development (petroleum products, coal) has been occurring in sage-grouse habitats since the late 1800s (Connelly

et al.

2004). Interest in development of oil and gas has been sporadic and typically focused in limited geographical areas (Braun

et al.

2002). The re-authorization of the Energy Policy and Conservation Act in 2000 dictated re-inventory of Federal oil and gas reserves, which identified extensive reserves in the Greater Green River Basin of Colorado, Utah, and Wyoming, the San Juan Basin of New Mexico and Colorado, and the Montana Thrust Belt and the Powder River Basin of Wyoming and Montana (Connelly

et al.

2004). All of these basins are located in primarily sagebrush-dominated landscapes (Knick

et al.

2003; Connelly

et al.

2004).

The development of oil and gas resources requires surveys for economically recoverable reserves, construction of well pads and access roads, subsequent drilling and extraction, and transport of oil and gas, typically through pipelines. Ancillary facilities can include compressor stations, pumping stations and electrical facilities (Connelly

et al.

2004). Surveys for recoverable resources occur primarily through seismic activities, using vibroesis buggies (thumpers) or shothole explosives. Well pads vary in size from 0.10 ha (0.25 ac) for coalbed natural gas wells in areas of level topography to greater than 7 ha (17.3 ac) for deep gas wells (Connelly

et al.

(2004). Pads for compressor stations require 5 to 7 ha (12.4 to 17.3 ac; Connelly

et al.

2004). Well densities and spacing are typically designed to maximize recovery of the resource and are administered by State and Provincial oil and gas agencies and the BLM (on Native American lands) (Connelly

et al.

2004). Based on their review of project EIS's, Connelly

et al.

(2004) concluded that the economic life of a coalbed methane well averages 12 to 18 years and 20 to 100 years for deep oil and gas wells.

Connelly

et al.

(2004) reviewed oil and gas development environmental impacts statements to determine that approximately 4,000 oil and gas wells have been approved in the Green River Basin of Wyoming, Colorado and Utah, with approval of an additional 9,700 wells pending. In the Powder River Basin of Wyoming and Montana, 15,811 wells have been approved, and an additional 65,635 are being considered (Connelly

et al.

2004). In the Uinta/Piceance Basin of Utah, 3,500 wells have been drilled and another 2,600 are pending (Connelly

et al.

2004). Approximately 3,000 more permits will be issued annually for Montana, Colorado, Utah and Wyoming (Connelly

et al.

2004). Nine million hectares (22.2 million ac) in Montana, Wyoming, Colorado, Utah and New Mexico are available for oil and gas leasing, and approval for 29,000 new oil and gas leases is anticipated by 2005 (BLM 2003c). The BLM has not quantified the portion of these lands that provide sage-grouse habitat. In September, 2004, the Utah BLM office sold 279 oil and gas leases, incorporating approximately 195,000 ha (481,000 ac) on both BLM and Forest Service surfaces (BLM 2004c). Based on a review of National

Environmental Policy Act (NEPA) documents, there are 27,231 existing oil and gas wells in sagebrush habitats, and another 78,938 to 79,647 are proposed.

Potential impacts to sage-grouse and sagebrush habitats from the development of oil and gas resources include direct habitat loss, habitat fragmentation from vegetation removal, roads, powerlines and pipeline corridors, noise, gaseous emissions, changes in water availability and quality, and increased human presence (Suter 1978; Aldridge 1998; Braun 1998; Aldridge and Brigham 2003; Knick

et al.

2003; Lyon and Anderson 2003; Connelly

et al.

2004). We found no information regarding the effects of gaseous emissions produced by oil and gas development. Presumably, as with surface mining, these emissions are quickly dispersed in the windy, open conditions of sagebrush habitats (Moore and Mills 1977), minimizing the potential effects on sage-grouse.

Direct habitat losses result from construction of well pads, roads, pipelines, powerlines, and potentially through the crushing of vegetation during seismic surveys. For example, coal-bed methane development in the Powder River Basin of Wyoming is expected to result in the loss of an additional 21,711 ha (53,626 ac) of sagebrush habitat by 2011 (BLM 2003a). This is less than 1 percent of the Connelly

et al.

(2004) assessment area. Current sage-grouse habitat loss in the Basin from coal-bed methane is estimated at 2,024 ha (5,000 ac) (Braun

et al.

2002).

Connelly

et al.

(2004) estimated that habitat loss from all existing natural gas pipelines in the conservation assessment area was a minimum of 4,740 km

2

(1,852 mi

2

, 1.17 million ac, 474,000 ha; less than 1 percent of their assessment area). Proposed pipelines to support future oil and gas developments are not included in this figure. Although reclamation of short-term disturbances is often concurrent with project development, habitats would not be restored to pre-disturbance conditions for an extended period (BLM 2003a). The amount of direct habitat loss within an area will ultimately be determined by well densities and the associated loss from ancillary facilities. Most Federal land management agencies impose stipulations to preclude exploration in suitable habitat during the nesting season.

Reclamation of areas disturbed by oil and gas development can be concurrent with field development. As disturbed areas are reclaimed, sage-grouse may repopulate the area. However, there is no evidence that populations will attain their previous size, and re-population may take 20 to 30 years, as habitat conditions are not immediately restored (Braun 1998). For most developments, return to pre-disturbance population levels is not expected due to a net loss and fragmentation of habitat (Braun

et al.

2002). After 20 years, sage-grouse have not recovered to pre-development numbers in Alberta, even though well pads in these areas have been reclaimed (Braun

et al.

2002). In some reclaimed areas, sage-grouse have not returned (Aldridge and Brigham 2003).

Habitat fragmentation impacts to sage-grouse resulting from vegetation removal, roads, powerlines and pipeline corridors are similar to those described previously. Fragmentation resulting from oil and gas development and the associated introduced infrastructure may have more effects on greater sage-grouse than the associated direct habitat losses, which may not be extensive. For example, of the total 904,109 ha (2,234,103 ac) project area in the Powder River Basin, an estimated 23,735 ha (58,625 ac) of habitat will be directly disturbed by well construction (BLM 2003a). However, up to 8,579 km (5,311 mi) of powerlines, 28,572 km (17,754 mi) of roads, and 33,548 km (20,846 mi) of pipelines are also proposed for this project. The presence of these ancillary facilities may preclude sage-grouse from using suitable adjacent habitats (see previous discussion). As previously discussed, roads associated with oil and gas development were suggested to be the primary impact to greater sage-grouse due to their persistence and continued use even after drilling and production has ceased (Lyon and Anderson 2003).

Noise can drive away wildlife, cause physiological stress and interfere with auditory cues and intraspecific communication, as discussed previously. Aldridge and Brigham (2003) reported that, in the absence of stipulations to minimize the effects, mechanical activities at well sites may disrupt sage-grouse breeding and nesting activities. Hens bred on leks within 3 km (1.9 miles) of oil and gas development in the upper Green River Basin of Wyoming selected nest sites with higher total shrub canopy cover and average live sagebrush height than hens nesting away from disturbance (Lyon 2000). The author hypothesized that exposure to road noise associated with oil and gas drilling may have been one cause for the difference in habitat selection. However, noise could not be separated from the potential effects of increased predation resulting from the presence of a new road. Above-ground noise is typically not regulated to mitigate effects to sage-grouse or other wildlife (Connelly

et al.

2004). Ground shock from seismic activities may affect sage-grouse if it occurs during the lekking or nesting seasons (Moore and Mills 1977). We are unaware of any research on the impact of ground shock to sage-grouse.

Water quality and quantity may be affected in oil and gas development areas. The impacts are similar relative to the contamination of water supplies by toxic elements and pathogens (see previous discussion), with the addition of potential oil contamination in settling and/or condensate ponds. In many large field developments, water produced during the gas dehydration process is stored in tanks, removing this potential threat. Where oil contamination of open water pits has occurred, no sage-grouse mortalities are known (Pedro Ramirez, U.S. Fish and Wildlife Service, pers. comm. 2004). Water may also be depleted from natural sources for drilling or dust suppression purposes. Remaining wetlands may subsequently receive increased use from other wildlife or domestic livestock, resulting in habitat degradation. Since, sage-grouse do not require free water (Schroeder

et al.

1999) we anticipate that impacts to water quality from mining activities have minimal effects on them. The possible exceptions are a reduction in habitat quality (

e.g.

, trampling of vegetation, changes in water filtration rates), habitat degradation (

e.g.

, poor vegetation growth), which could result in brood habitat loss. However, we have no data to suggest this is a limiting factor to sage-grouse.

Water produced by coal-bed methane drilling may benefit sage-grouse through expansion of existing wetland and riparian areas, and creation of new areas (BLM 2003a). These habitats could provide additional brood rearing and summering habitats for sage-grouse. However, based on the recent discovery of West Nile virus in the Powder River Basin, and the resulting mortalities of sage-grouse (Naugle

et al.

2004), there is concern that produced water could be a negative impact if it creates suitable breeding reservoirs for the mosquito vector of this disease. There is currently no evidence supporting a link between West Nile virus and coal-bed methane development (Naugle

et al.

2004). Produced water could also result in direct habitat loss through prolonged flooding of sagebrush areas, or if the discharged water is of poor quality because of high salt or other mineral content, either of which could result in the loss of sagebrush and/or grasses and forbs necessary for foraging broods

(BLM 2003a). We do not have quantitative information on the extent of habitat influenced by produced water, nor the net effects on sage-grouse populations.

Increased human presence resulting from oil and gas development can also impact sage-grouse either through avoidance of suitable habitat, disruption of breeding activities, or increased hunting and poaching pressure (Aldridge and Brigham 2003; Braun

et al.

2002; BLM 2003a). Sage-grouse may also be at increased risk for collision with vehicles simply due to the increased traffic associated with oil and gas activities (BLM 2003a).

Only a few studies have examined the effects of oil and gas development on sage-grouse. While each of these studies reported sage-grouse population declines, specific causes for the negative impacts were not determined. In Alberta, Canada, the development of well pads and associated roads in the mid-1980s resulted in the abandonment of three lek complexes within 200 m (220 yd) of these features (Braun

et al.

2002). Those leks have not been active since that time. A fourth lek complex has gone from three to one lek with fewer numbers of sage-grouse on it (Braun

et al.

2002). The well pads have since been reclaimed, but sage-grouse numbers have not recovered (we do not have information on post-reclamation vegetation). Subsequent to the development of the Manyberries Oil Field in high quality sage-grouse habitat in Alberta, male sage-grouse counts fell to the lowest known level (Braun

et al.

2002). Two additional leks were directly disturbed, and neither of these leks has been active within the past 10 years (Braun

et al.

2002). The development of oil reserves in Jackson County, Colorado, was concurrent with decline of sage-grouse numbers in the oil field area (Braun 1998). Sage-grouse populations still occur in at least one long-term oil field development in Colorado where leks are not within line-of-sight of an active well or powerline (Braun

et al.

2002). Although the number of active leks has declined in this field, sage-grouse have been consistently documented there since 1973.

Of particular relevance to estimating oil and gas development impacts is the fidelity of sage-grouse hens to nesting and summer brood rearing areas demonstrated by Lyon and Anderson (2003). Hens that have successfully nested will return to the same areas to nest every year. If these habitats are affected by oil and gas development, there is a strong potential that previously successful hens will return but not initiate nests (Lyon 2000). Depending on the number of hens affected, local populations could decline.

Over 200 known leks occur within the coal-bed methane development area in Powder River Basin of northeastern Wyoming. Those leks have been affected by direct habitat losses, higher human activity, and powerlines (Braun

et al.

2002). Since initiation of field development, 28 percent of known sage-grouse habitat within the project area has been affected. On 30 leks within 0.4 km (0.25 mi) of a well, significantly fewer males have been recorded when compared with other, undisturbed leks. The rate of recruitment to the male breeding population on these leks is also lower when compared with increases on less disturbed leks (Braun

et al.

2002; BLM 2003a). Powerlines have been constructed within 0.4 km (0.25 mi) of 40 leks within the project area. These leks also have lower recruitment rates, possibly due to increased raptor predation. Lower numbers of grouse have also been counted on leks within 1.6 km (1 mi) of compressor stations (Braun

et al.

2002). In the Final EIS for this project, the BLM stated that local sage-grouse extirpations may occur as a result of the synergistic effects of all aspects of coal-bed methane development in this area (BLM 2003a).

In the Jonah natural gas field in southwestern Wyoming, 10 of 24 leks in or near the project area are no longer active, although data collection has not been consistent on 4 of those leks (BLM 2004d). Two leks were destroyed by the placement of well pads on the leks, and re-establishment of those leks at that location is not anticipated (BLM 2004d). Based on nest initiation and habitat fidelity results, Lyon and Anderson (2003) concluded that impacts occur greater than 0.4 km (0.25 mi) from well pads, thus current no-surface-occupancy buffers around active sage-grouse based on that distance may not be adequate to avoid adverse effects. However, to our knowledge no information exists concerning whether leks are subsequently re-established.

Protective wildlife stipulations are typically placed on individual oil and gas leases at the time of sale, including seasonal and temporal restrictions around important sage-grouse habitats (Connelly

et al.

2004). The protection afforded by these stipulations depends on the specific prescriptions, and whether or not important sage-grouse habitats are identified in the area proposed for development. Additional stipulations may be placed on oil and gas development, as identified in BLM land use plans, and through the NEPA process. Most lease stipulations have exception, waiver, and/or modification criteria that are included in BLM land use plans. Waivers, which are a permanent exemption, and modifications, which are changes to the terms of a stipulation, are described by BLM as being rare, and they also may require public notice (BLM 2004a). Exceptions are a one-time exemption to a lease stipulation. An example cited by BLM is a timing stipulation designed to avoid activity in wintering habitat, which could be the subject of an exception in a mild winter if a company requests an early entry to drill and BLM or the local wildlife agency make an on-the-ground survey and find sage-grouse are not using the winter habitat or have left the area earlier than normal (BLM 2004a).

On June 22, 2004, BLM issued an Instruction Memorandum (IM) establishing policy that BLM field offices consider Best Management Practices (BMPs) for oil and gas and other fluid mineral operations as part of NEPA documents. The purpose of the BMPs is to mitigate anticipated effects to surface and subsurface resources, and to encourage operators to consider BMPs during the application process for permits to drill (BLM 2004e). BLM expects that wells drilled using BMPs will have fewer impacted acres of sagebrush habitat than has been estimated in EISs (

e.g.

, for the Powder River EIS) and consequently there will be less habitat loss and fragmentation (BLM 2004a). The effect of the IM and the BMPs is difficult to predict. Although the IM makes it BLM policy to consider the BMPs, their adoption is voluntary, not mandatory. The Service is available to provide BLM with technical assistance as they implement BMPs.

The Forest Service can place additional seasonal or temporal stipulations to protect sage-grouse on oil and gas developments on lands they manage (Forest Service in litt. 2004). Development of oil and gas resources on private lands does not always require mitigation (Braun 1998; Connelly

et al.

2004), and most States do not place wildlife stipulations on development occurring on their lands. In Canada, no current legislation commits energy development to adhere to recommendations by Alberta Fish and Wildlife to reduce impacts of drilling in important sage-grouse habitats (Braun

et al.

2002).

Renewable energy resources, such as windpower and geothermal energy, require many of the same features for construction and operation as do non-

renewable energy resources. Therefore, we anticipate that potential impacts from direct habitat losses, habitat fragmentation through roads and powerlines, noise, and increased human presence (Connelly

et al.

2004) will generally be the same as already discussed for nonrenewable energy development. Windpower may have additional mortalities resulting from sage-grouse flying into turbine rotors or meteorological towers (Erickson

et al.

2001). One sage-grouse was found dead within 45 m (148 ft) of a turbine on the Foote Creek Rim wind facility in south-central Wyoming, presumably from flying into a turbine (Young

et al.

2003). During 3 years of monitoring operation, this is the only known sage-grouse mortality at this facility. Sage-grouse hens with broods have been observed using Foote Creek Rim, under the turbines, during surveys for other species (David Young, WEST, Inc., pers. comm. 2004). Mortalities at other facilities within sagebrush habitats are unknown and may not be monitored. However, most developed windpower facilities are not located within sagebrush habitats, and the average above-ground height of windpower facilities is 107 m (350 ft; Erickson

et al.

2001), above the normal height of short-distance sage-grouse flights (Johnson

et al.

2000).

Fifteen thousand wind turbines were projected to be operational in the United States by the end of 2001, not including the wind turbines located in California (Erickson

et al.

2001). On September 10, 2004, the BLM released a draft programmatic EIS regarding the modification of land use plans in western States (including all States within the extant sage-grouse range) for the increased development of wind resources (BLM 2004f). Locations and potential impacts to sage-grouse were not discussed in specific detail.

Development of hydropower energy may impact sage-grouse through direct habitat losses, and increases in human traffic and activity if a resulting reservoir provides recreational resources. During construction, there may also be additional impacts of fugitive dust, gaseous emissions, road construction, increased traffic, and increased poaching activities. We do not anticipate that the potential for impacts from these activities to sage-grouse are different from those discussed previously for infrastructure issues. During the mid-1900s, 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 precipitated conversion of large expanses of upland shrub-steppe habitat in the Columbia Basin for irrigated agriculture adjacent to the rivers as discussed previously in the Agriculture section (65 FR 51578). The creation of these reservoirs also directly inundated hundreds of kilometers of riparian habitats used by sage-grouse broods (Braun 1998). We were unable to find any information regarding the amount of sage-grouse habitat affected by hydropower projects in other areas of the species range beyond the Columbia Basin. We do not anticipate that future dam construction will result in large losses of sagebrush habitats. Although dam removal has been proposed for some areas, upland restoration goals, and the potential benefit to sage-grouse, are unknown.

The development of geothermal energy requires intensive human activity during field development (Suter 1978). Toxic gases may be released, and the type and effect of these gases depends on the geological formation in which drilling occurs. The amount of water necessary for drilling and condenser cooling may be high (Suter 1978). Therefore, water depletions may be a concern if such depletions result in the loss of limiting brood-rearing habitats (

see

discussion above). Geothermal activity on public lands is primarily in California, with over 23 producing leases. Nevada, and Utah also have producing leases (BLM 2004g). Impacts to sage-grouse were not identified.

We were unable to find any information regarding the commercial development of solar energy. We anticipate the effects from this resource will be those associated with direct habitat loss, fragmentation, roads, powerlines, increased human presence, and disturbance during facility construction, where solar energy development occurs.

Energy development was identified by the expert panel as the most significant extinction risk to the greater sage-grouse in the eastern portion of its range (Colorado, Wyoming and Montana). Their primary concern was the rapidity of development and the persistent demand for petroleum products. On a rangewide scale, however, energy development alone (not including the infrastructure associated with it—see Roads and Railroads above) ranked as the sixth most important extinction risk factor. To better understand the actual mechanism by which energy development affects greater sage-grouse, the panel suggested excluding some areas from extraction activities so that comparative analyses could be conducted.

Fire

The effects of fire on sagebrush habitats vary according to the species of sagebrush present, other plant species present (

e.g.,

the understory) and the frequency, size and intensity of fires. Widely variable estimates of mean fire intervals have been described in the literature: 35 to 100 years (Brown 2000), greater than 50 years for big sagebrush communities (McArthur 1994), 12 to 15 years for mountain big sagebrush (Miller and Rose 1999), 20 to 100 years (Peters and Bunting 1994), 10 to 110 years depending on sagebrush species and specific geographic area (Kilpatrick 2000), and 13 to 25 years (Frost 1998 cited in Connelly

et al.

2004).

In general, fire tends to extensively reduce the sagebrush component within the burned areas. Big sagebrush (

A. tridentata

spp.), the most widespread species of sagebrush (McArthur 1994), is killed by fire. It does not re-sprout after burning (Agee 1994, Braun 1998, Wrobleski and Kauffman 2003), and can take as many as 30 to 50 years to recolonize an area (Agee 1994, Telfer 2000, Wambolt

et al.

2001). 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). However, as noted by the expert panel, fire has been an important component in sagebrush systems.

A characteristic of natural fire in sagebrush stands is the incomplete burning that leaves areas of unburned sagebrush (sometimes referred to as islands of habitat) (Huff and Smith 2000). Huff and Smith (2000) noted that these unburned islands appear to be important to the future recolonization of the sagebrush community by providing sources of sagebrush seed. Prior to settlement by European immigrants, fire patterns in sagebrush communities were patchy, particularly in Wyoming big sagebrush, due to the discontinuous and limited fuels and unburned islands that remained after a fire (Miller and Eddleman 2000).

Connelly

et al.

(2004) summarized fire statistics from records obtained for the sagebrush biome (both wild and prescribed fires). The total area burned and the number of fires increased across the sagebrush ecoregions from 1960 to 2003. In the Southern Great Basin and Wyoming basins, average fire size increased. In the 40.5 million ha (100 million ac) sagebrush-steppe ecoregion (essentially the northern distribution of sagebrush), or drier sagebrush areas fire regimes have shifted to more frequent

fire episodes (Brown 2000). Fire was identified as the primary factor resulting in sage-grouse habitat conversion in Oregon (1.4 million ac; Oregon Department of Fish and Wildlife in litt. 2004).

In parts of the Great Basin (Nevada, Oregon and Utah) a decline in fire occurrence since the late 1800s has been reported in several studies, which coincides with fire suppression and reduction of fuels by introducing livestock (Touchan

et al.

1995, Miller and Rose 1999, Kilpatrick 2000, Connelly

et al.

2004). Long fire intervals and fire suppression can result in increased dominance of woody conifer species, such as western juniper (

Juniperus occidentalis

) (Wrobleski and Kauffman 2003), resulting in a near total loss of shrubs and sage-grouse habitat in localized areas (Miller and Eddleman 2000). Alternatively, invasion of exotic annuals, such as cheatgrass and medusahead (

Taeniatherum asperum

), has resulted in increases in the frequency and number of fires within the range of the greater sage-grouse (Young and Evans 1973, Brown 2000, Wrobleski and Kauffman 2003, Connelly

et al.

2004). Following fire, sagebrush will not re-establish on its own for long time intervals, while non-native grasses quickly recover from fire and increase, effectively preventing sagebrush return. Management to restore an area to sagebrush after cheatgrass becomes established is difficult and usually ineffective (Paysen

et al.

2000). As a result of this direct relationship between wildfire and the spread of invasive plants, large areas of habitat in the western distribution of the greater sage-grouse have already been converted to cheatgrass (Connelly

et al.

2000c). The loss of habitat due to establishment of and dominance by non-native annual grasses results in the loss of sage-grouse populations (Connelly

et al.

2000c).

Wildfires have removed extensive areas of sagebrush habitat in recent years. For example, 30 to 40 percent of the sage-grouse habitat in southern Idaho was destroyed in a 5-year period (1997-2001) due to range fires (Signe Sather-Blair, U.S. Bureau of Land Management, quoted in Healy 2001). The largest contiguous patch of sagebrush habitat in southern Idaho occupied approximately 283,000 ha (700,000 ac), (Michael Pellant, U.S. Bureau of Land Management, quoted in Healy 2001). Of that total area, about 202,000 ha (500,000 ac) burned in the years 1999 to 2001; half of the acres that burned for the first 3 to 5 years post fire, but accompanying forbs and surviving grasses increased biomass production. In another study, productivity of perennial herbs had increased by the second year post-burn to an average 2.2 times higher on burned verses control areas (Cook

et al.

1994). In a 1998 prescribed burn on the Hart Mountain National Antelope Refuge, Crawford (1999) observed little change in species composition between unburned and burned areas. In the same general area, fall burning had no apparent effect on most primary foods although some Cichorieae species did increase (Pyle 1992). Fischer

et al.

(1996) also noted that vegetative cover of important forbs in the diets of sage-grouse was similar in unburned and burned habitat. In a review of 13 sites that had burned during a span of 2 to 32 years, Wambolt

et al.

(2001) reported that perennial grasses and forbs did not benefit from prescribed burning.

A variety of techniques have been attempted at re-establishing sagebrush post-fire, with mixed success (Cadwell

et al.

1996, Quinney

et al.

1996, Livingston 1998). Restoration of the sagebrush biome following a fire has been complicated not only by the invasion of exotic annual plant species, but the difficulty associated with establishing sagebrush seedlings (Boltz 1994). Wirth and Pyke (2003) reported that forb response post-fire is dependant on the forb community pre-burn. Habitat rehabilitation following fires has become a major activity in recent years, increasing from 281 km

2

(109 mi

2

) in 1997 to 16,135 km

2

(6,230 mi

2

) in 2002 with most treatments in Oregon, Idaho, and Nevada (Connelly

et al.

2004), but we have no data on the extent of actual sagebrush restoration.

A clear positive response of greater sage-grouse to fire has not been demonstrated (Braun 1998). Call and Maser (1985) noted that fires could cause adverse conditions where cover is limited. Studies of prescribed fire in mountain big sagebrush at Hart Mountain National Antelope Refuge demonstrate short-term benefits in certain forbs, but the reduction in sagebrush cover potentially rendered habitat less suitable for nesting and brood rearing (Rowland and Wisdom 2002). Similarly, Nelle

et al.

(2000) reported that the removal of sage-grouse nesting and brood-rearing habitat by fire resulted in no increase in invertebrate abundance in the first year post-fire and hence, no benefit for sage-grouse chick foraging. This loss of nesting habitat created a long-term negative impact which would require 20 years of sagebrush re-growth before sufficient canopy cover was available for nesting birds (Nelle

et al.

2000). Byrne (2002) reported the general avoidance of available burned habitats by nesting, brood-rearing, and broodless females. Connelly

et al.

(2000c) and Fischer

et al.

(1996) found that prescribed burning did not improve brood rearing habitat in Wyoming big sagebrush, as forbs did not increase and insect populations declined as a result of the treatment. Hence fire in this sagebrush type may negatively affect brood rearing habitat rather than improve it (Connelly and Braun 1997). However, Klebenow (1970), Gates (1983, as cited in Connelly

et al.

2000c), Sime (1991 as cited in Connelly

et al.

2000a), and Pyle and Crawford (1996) all indicated that fire could improve brood-rearing habitat. Slater (2003) reported that sage-grouse using burned areas were rarely found more than 60 m (200 feet) from the edge of the burn. In southeastern Idaho, Connelly

et al.

(2000c) concluded that, even though age-grouse populations were in decline across the study area, population declines were more severe in the post-fire years. Fischer

et al.

(1997) concluded that habitat fragmentation, as a result of fire, may influence distribution or migratory patterns in sage-grouse. Hulet (1983, as cited in Connelly

et al.

2000a) documented the loss of leks as a result of fire.

The expert panel ranked wildfire as the second most important extinction risk factor for the greater sage-grouse in western portions of its range (the Great Basin—Utah, Idaho, Nevada, eastern Oregon), primarily due to the subsequent establishment of invasive species such as cheatgrass (see following discussion). Since invasive species has not become the problem in the eastern part of the greater sage-grouse range, the expert panel did not rank wildfire as high in that area. Across the species range, wildfire was identified as the third most important extinction risk factor by the expert panel.

Invasive Species/Noxious Weeds

Invasive species have been defined as those that are not native to an ecosystem and whose introduction causes, or is likely to cause, economic or environmental harm or harm to human health (Executive Order 13112, 1999). A wide variety of plants are considered invasive within the range of sagebrush ecosystems that the greater sage-grouse occupies (Wamboldt

et al.

2002, Crawford

et al.

2004, Connelly

et al.

2004). Invasive species often cause declines in native plant populations by reducing light, water, and nutrients, and they grow so quickly that they outcompete other species (Wooten

et al.

1996). The rate of spread for noxious weeds is approximately 931 ha (2,300 ac) per day on BLM lands and 1862 ha

(4,600 ac) per day on all public lands in the West (Knick

et al.

2003). The area infested with exotic (non-native) invasive plants increased from 1.1 million ha (2.7 million ac) in 1985 to 3.2 million ha (7.9 million ac) in 1994 on BLM lands (Knick

et al.

2003). The replacement of sagebrush vegetation communities with exotic species such as Russian thistle (

Salsola

spp.), halogeton (

Halogeton glomeratus

) and medusahead, has resulted in sage-grouse habitat loss (Miller and Eddleman 2000).

Young

et al.

(1972) found that plant communities of the Great Basin are highly susceptible to invasion by alien plants since native annuals are not adapted to occupy conditions created by intensive livestock grazing. Exotic plants can reduce and eliminate populations of plants that sage-grouse use for food and cover. As previously discussed, frequent fires with short intervals within sagebrush habitats favor invasion of cheatgrass, which is unsuitable as sage-grouse habitat (Schroeder

et al.

1999). Cheatgrass then shortens the fire interval (from approximately 30 years down to 5 years), perpetuating its own persistence and spread, and exacerbating the effects of fire in remaining sage-grouse habitats (Connelly

et al.

2004). Rehabilitation of an area to sagebrush after cheatgrass becomes established is extremely difficult (Connelly

et al.

2004).

Large areas of habitat in the western distribution of the greater sage-grouse have already been converted to cheatgrass (Connelly

et al.

2000a). Exotic plant communities are now dominant on more than 40 million ha in the Intermountain West (Mack 1981, as cited in Miller and Eddleman 2000). This invasive species also occurs in lower abundance throughout the entire range of the sage-grouse. Connelly

et al.

(2004) estimated the risk of cheatgrass invasion into sagebrush and other natural vegetation areas in the western part of the range of greater sage-grouse (Southern and Northern Great Basin, part o

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