We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0036; Directorate Identifier 2009-NM-077-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

We have received reports of cracks of the skin and surrounding structure under the number 3 (very high frequency) VHF antenna on the lower external surface of the airplane at Buttock Line 0.0, aft of the main landing gear wheel well on Model 737-200, -200C, -300, -400, and- 500 series airplanes. One report indicated there was a 15-inch longitudinal crack in the skin near Buttock Line 0.0 just forward of the number 3 VHF antenna cutout, running forward. The first 14 inches of the crack was hidden beneath the number 3 VHF antenna. Five other reports indicated there were skin cracks between 1.5 and 3 inches in length in the same area. The reports also indicated that the main antenna support channel and other support structure were cracked. The earliest reported cracks were at 18,289 flight cycles. This condition, if not corrected, could result in crack growth, possibly leading to separation of the antenna from the airplane, and rapid depressurization of the airplane.

We have reviewed Boeing Special Attention Service Bulletin 737-53-1287, dated March 11, 2009. The service bulletin describes procedures for repetitive external detailed and external high frequency eddy current (HFEC) inspections for cracking and corrosion in the skin; and repetitive internal detailed inspections for cracking and corrosion in the skin, antenna support structure, and surrounding frames and stringers; depending on the airplane configuration. For Group 1-4, configuration 2 airplanes, having a cover plate at the number 3 VHF antenna location, accomplishing the HFEC inspection eliminates the need for repetitive external detailed inspections.

Boeing Special Attention Service Bulletin 737-53-1287, dated March 11, 2009, also specifies contacting Boeing for certain inspection instructions, and for all repair instructions.

The initial compliance time is 15,000 total flight cycles, or within 1,100 or 6,000 flight cycles (depending on configuration and inspection type) from the date on the service bulletin, whichever occurs later, for the following inspections:

• External detailed inspections for any crack in the skin;

• External HFEC inspections for any crack in the skin;

• Internal detailed inspection for any crack in the skin, antenna support structure, and surrounding frames and stringers; and

• Internal detailed inspection for any crack or corrosion in the skin, antenna support structure, and surrounding frames and stringers.

The initial compliance time is within 18,000 flight cycles (depending on configuration and inspection type) from the date on the service bulletin, for the following inspections:

• External detailed and HFEC inspection for any crack or corrosion in the skin; and

• Internal detailed inspection for any crack or corrosion in the skin.

The repetitive inspection intervals, which depend on the airplane configuration and inspection type, range between 1,100 flight cycles and 18,000 flight cycles.

Boeing Special Attention Service Bulletin 737-53-1287, dated March 11, 2009, specifies prior or concurrent accomplishment, for certain airplanes, of the replacement of bonded skin panels with solid skin panels in accordance with Part 5 of Boeing Service Bulletin 737-53A1042, Revision 5, dated October 5, 1984. The actions specified in Boeing Service Bulletin 737-53A1042, Revision 5, dated October 5, 1984, are necessary to comply with AD 90-06-02, Amendment 39-6489 (55 FR 8372, March 7, 1990).

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs. This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between the Proposed AD and Service Bulletin.”

Boeing Special Attention Service Bulletin 737-53-1287, dated March 11, 2009, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

• Using a method that we approve; or

• Using data that meet the certification basis of the airplane, and that have been approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings.

We consider this proposed AD interim action. If final action is later identified, we might consider further rulemaking then.

We estimate that this proposed AD would affect 1,016 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866,

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and

3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

Entities potentially affected by this action include sources in all industry groups and state, local, and tribal governments.

The preamble is organized as follows:

When undergoing a physical or operational change, a source determines major NSR applicability through a two-step analysis that first considers whether the increased emissions from a particular proposed change alone are significant, followed by a calculation of the change's net emissions increase considering all contemporaneous increases and decreases at the source ( i.e., source-wide netting calculation) to determine if a major modification has occurred. See, for example, 40 CFR 52.21(b)(2)(i). The term “aggregation” comes into play in the first step (Step 1), and describes the process of grouping together multiple, nominally-separate but related physical changes or changes in the method of operation (“nominally-separate changes”) into one physical or operational change, or “project.” The emission increases of the nominally-separate but related changes must be combined in Step 1 for purposes of determining whether a significant emissions increase has occurred from the project. See, for example, 40 CFR 52.21(b)(40). When undertaking multiple nominally-separate changes, the source must consider whether NSR applicability should be determined collectively ( i.e., “aggregated”) or whether the emissions from each of these changes should separately undergo a Step 1 analysis. 1

Neither the CAA nor current EPA rules specifically address the basis upon which to aggregate nominally-separate changes for the purpose of making NSR applicability determinations. Instead, our  2 aggregation policy developed over time through statutory and regulatory interpretation and applicability determinations in response to a need to deter sources from attempting to expedite construction by permitting several changes separately as minor modifications. When related changes are evaluated separately, the source may circumvent the purpose of the NSR program by showing a less than significant emission increase for Step 1 of the applicability analysis, that could result in avoiding major NSR permitting requirements. 3 This, in turn, could result in increases of emissions of air pollutants from the facility that would be higher than the increases would be had the changes been subject to NSR control requirements. The associated emissions increases could endanger the air quality health standard and adversely affect public health.

Under our longstanding aggregation policy, we evaluate all relevant and objective criteria specific to a case in determining if multiple changes at a source should be aggregated as a single project for NSR purposes. See section III.C.2.a of this notice. Our policy aims to ensure the proper permitting of modifications that involve multiple physical and/or operational changes.

On January 15, 2009, we issued a final rule that changed our interpretation of the PSD and nonattainment NSR regulations relating to the definition of “modification” in the CAA 111(a)(4). The new rule addressed when a source must aggregate emissions from nominally-separate changes for the purpose of determining whether they are a single project resulting in a significant emission increase. The final rule retained the prior rule language relevant to aggregation, but interpreted that rule text to mean that sources and permitting authorities should combine emissions only when nominally-separate changes are “substantially related.” We described in the final rule preamble the factors that may be considered when evaluating whether changes are substantially related, and we specifically stated that two nominally-separate changes are not substantially related if they are only related to the extent that they both support the plant's overall basic purpose. At the same time, we adopted a rebuttable presumption that nominally-separate changes at a source that occur three or more years apart are presumed to not be substantially related. Collectively, this rulemaking is known as the “NSR Aggregation Amendments.” For further information on the NSR Aggregation Amendments, see 74 FR 2376 (January 15, 2009).

On January 30, 2009, NRDC submitted a petition for reconsideration of the NSR Aggregation Amendments as provided for in CAA section 307(d)(7)(B). 4 Under that CAA provision, the Administrator may convene a reconsideration proceeding if the petitioner raises an objection to a rule that was impracticable to raise during the comment period or if the grounds for the objection arose after the comment period. In either case, the objection must be of central relevance to the outcome of the rule.

On February 13, 2009, we announced the convening of a reconsideration proceeding in response to the NRDC petition. See 74 FR 7193. In order to allow for completion of the reconsideration prior to the NSR Aggregation Amendments becoming effective, we also announced a 90-day administrative stay of the rule. See 74 FR 7284 (Feb. 13, 2009). We subsequently completed a rulemaking further delaying the effective date until May 18, 2010. See 74 FR 22693 (May 14, 2009). The extensions enable us to take comment on issues that are in question and complete any revisions of the rule that become necessary as a result of the reconsideration process.

As noted above, pursuant to CAA 307(d)(7)(B) of the CAA, an individual can petition an agency to reconsider a final rule issued under CAA 307(d)(1) if the individual can show that:

• It was impracticable to raise the objection during the public comment period on the proposed rule, or the grounds for the objection arose after the public comment period; and

• The objection is centrally relevant to the outcome of the rule.

As to the first procedural criterion for reconsideration, a petitioner must show why the issue could not have been presented during the comment period, either because it was impracticable to raise the issue during that time or because the grounds for the issue arose after the period for public comment (but within 60 days of publication of the final action). Thus, CAA 307(d)(7)(B) does not provide a forum to request EPA to reconsider issues that actually were raised, or could have been raised, prior to promulgation of the final rule.

An agency can deny the reconsideration of issues when they fail to meet the procedural test for reconsideration under CAA 307(d)(7)(B). If, however, there are adequate grounds for the objections raised in this petition, the EPA Administrator must “* * *convene a proceeding for reconsideration of the rule and provide the same procedural rights as would have been afforded had the information been available at the time the rule was proposed.” CAA 307(d)(7)(B). In this case, the final rule adopted interpretations that were not described in the proposal and on which the public did not have an opportunity to offer comment, as described more specifically below.

The basis for this reconsideration proceeding is NRDC's petition of January 30, 2009, in which NRDC requested reconsideration of many aspects of the January 15, 2009, final rule. The reader is directed to the petition for an exact explanation of each objection raised by NRDC. See Docket EPA-HQ-OAR-2003-0064-0116.1. In summary, NRDC's main points of concern include:

• The NSR Aggregation Amendments are inconsistent with the DC Circuit Court ruling on the NSR ”Equipment Replacement Provision,” by creating an illegal exclusion to the broad “any physical change” provision in the CAA.

• The EPA failed to identify any actual problems or inconsistencies with longstanding policy.

• The 2006 proposal sought to clarify aggregation rules through proposing new rule text, but the 2009 final rule reinterpreted the existing rule text and was described as a change in policy.

• The term “substantially related” is vague and undefined, did not appear in the proposal, retreats from the factors used in previous aggregation determinations by EPA ( e.g., adopting the 3-year timing presumption against aggregation), and eliminates consideration of EPA's policy on circumvention by failure to consider a company's intent.

• The final rule is silent, and therefore confusing, on whether States must implement the new rule in their own programs.

• The EPA violated relevant executive orders through failure to adequately consult with states during the development of the rule.

Through this notice, we are taking comment on a broad range of legal and policy issues related to the NSR Aggregation Amendments. We also acknowledge an interdependence among several objections raised in NRDC's petition, such that granting reconsideration on one issue that meets the standard for reconsideration may warrant taking comment on a second issue that may, on its own, not meet the standard for reconsideration. However, the basis for the second issue is at stake depending on what comments are received on the first issue.

For example, under CAA 307(d)(3)(C), EPA is required to present for public comment “the major legal interpretations and policy considerations underlying the proposed rule.” We acknowledge through this reconsideration proceeding that portions of the legal basis for the NSR Aggregation Amendments did not undergo comment solicitation, and it is necessary to allow the public an opportunity to comment fully on the basic authority for the rule. However, as is the case with many rules, the statutory basis of this rule provides the underpinning for most every aspect of the rule, and could call into question the legitimacy of other aspects of the rule. Therefore, in addition to granting reconsideration on the legal basis for the rule, we are also taking comment on other aspects of the final rule that are dependent upon a sound legal basis. For instance, although we requested comment on a 3-year presumption against aggregation through our 2006 proposal, in light of the broad legal issue that is currently under reconsideration, we believe it is justified to open for additional comment the issue of having a presumption against aggregation because such a presumption would be necessarily dependent on, and an outgrowth of, the legal basis of our rule.

Moreover, a few of the issues raised in the NRDC petition demonstrate that there are fundamental components of the final rule that elicit confusion, such as whether states with approved implementation plans must adopt the new rule and whether their State Implementation Plans (SIPs) must be amended. Since the aim of the rule was to reduce, not promote, confusion with regard to project aggregation, we are particularly concerned with this comment from the petitioner, and it is one of the primary reasons for delaying the effective date of the rule while we reconsider issues raised in the petition.

For these reasons, we invite comment on all issues raised by the petitioner. In the sections below, we specifically describe several key issues on which we seek comment.

As noted above, NRDC identifies as grounds for reconsideration several issues related to the adoption and implementation of the “substantially related” test for aggregating nominally-separate changes. The proposed rule did not mention the “substantially related” test adopted in the final rule. 5 Additionally, the proposed rule offered new regulatory text to clarify the criteria for aggregation, while the final rule retains the existing text. Our proposed rule did not discuss the possibility of changing the interpretation of the existing text.

A commenter would not have been on notice of the possibility that we would adopt the “substantially related” test without amending the rule text, nor would a commenter have been on notice of the need to comment on whether the existing text was susceptible to this interpretation. The issue of adopting this rule in the form and manner we did is an issue that arose after the comment period and is of central relevance to the rulemaking proceeding.

In soliciting comment on the option of creating time-based presumptions regarding aggregation, we did not raise the issue of whether the existing regulatory text could support the creation of this presumption. We “acknowledge[d] that the establishment of a presumption* * * would go beyond the codification of the status quo.” See 71 FR 54248. Therefore, we did not characterize a time-based presumption as a clarification. We recognized it could only apply prospectively. Nevertheless, the final rule announced the 3-year presumption against aggregation as an interpretation of the regulatory text despite the regulation's silence on this issue.

In context, commenters could not have been aware that we were suggesting the presumption was an interpretation of the existing regulatory text rather than a proposal to add a presumption to the text. Therefore, commenters did not have an adequate opportunity to comment on whether the existing regulatory text could be interpreted to have a time-based presumption.

We solicit comment on the change in approach from the pre-rule policy on aggregation to the “substantially related” test set forth in the preamble to the January 15, 2009, final rule. We specifically request comment on any rule changes that may be needed to implement the new test. For example, if we were to retain the “substantially related” test, then must we amend the regulatory text for the definition of “project” to say that nominally-separate changes must be aggregated into a project if they are substantially related? Must we also add new regulatory text in order to establish a time-based presumption for or against aggregation? We also solicit comment on whether we would need new or revised rule language to adopt a time-based presumption against aggregation.

Furthermore, we specifically request comment on whether “substantially related” is the proper measurement to apply when determining whether to aggregate projects. Or does it, as the petitioner has expressed, add confusion for sources and permitting authorities trying to apply the test? Is there another benchmark that would be more sensible to use to determine when the emissions of nominally-separate changes at a source should be aggregated for evaluating NSR applicability? If we decide to retain the substantially related test or revert to our former test, is the 3-year presumption against aggregation appropriate?

The NRDC petition identifies our interpretation of the controlling statutory term, “modification,” and a key case discussing that definition as issues that were impractical to raise during the comment period and of central relevance to the rule. While NRDC and other commenters identified these matters as being at issue in their comments, we did not include an explanation in the proposed rule of how the EPA aggregation interpretation was consistent with the statute and the court decision. In a sense, the rulemaking process required by CAA 307(d) was inverted: rather than the EPA providing a “statement of basis [summarizing] the major legal interpretations* * *underlying the proposed rule,” as required by CAA 307(d)(3)(C), the commenters provided their views of the law, and we then provided a legal basis in the final rule and in the response-to-comment document. Moreover, the rulemaking did not simply adopt a theory that was a logical outgrowth of the theory or theories suggested in the proposal. The portion of the proposal discussing aggregation was completely silent on how we interpreted CAA section 111(a)(4) to authorize aggregation and provided no analysis of the relevant case law.

Below we set out our understanding of the statute and case law. We invite comment on our understanding and what we believe would be the result from that understanding— i.e., the revocation of the NSR Aggregation Amendments and the reversion to our pre-existing policy on project aggregation.

Under both the nonattainment NSR provisions of the CAA as well as the PSD provisions, a modification of a major stationary source is treated as construction of a new source subject to permitting. Modification is a defined term under the statute: “The term `modification' means any physical change in, or change in the method of operation of, a stationary source which increases the amount of any air pollutant emitted by such source or which results in the emission of any air pollutant not previously emitted” (CAA section 111(a)(4)). This definition requires analyzing whether a physical or operational change will take (or, post hoc, has taken) place, and whether it results in an emission increase. As noted above, in situations involving multiple nominally-separate changes at a source, EPA's “aggregation” policy interprets what is the physical or operational change that must be assessed for an emission increase.

We calculate the emissions increase associated with a physical or operational change at a major stationary source by reference to de minimis thresholds (also known as “significance levels”). From the earliest days of the NSR program, we recognized that a party seeking to avoid major source NSR might attempt to break up a single physical or operational change into nominally-separate changes in order to make the emission increase associated with each change appear to be less than significant. See 45 FR 52702 (Aug. 7, 1980). As subsequent case law confirmed, even a small physical or operational change may satisfy the first portion of the definition of modification. State of New York v. EPA, 443 F.3d 880, 890 (DC Cir. 2006), cert. den. 127 S. Ct. 2127 (2007) ( New York II ); Wisconsin Elec. Power Co. v. Reilly, 893 F.2d 901, 908 (7th Cir. 1990). We recognized that an owner or operator might apply for multiple minor permits for nominally-separate, small changes that by themselves result in de minimis emission increases, instead of obtaining a permit for the collection of changes that, when examined as a single project, resulted (or would result) in a significant emission increase.

We issued several letters since the early 1980s explaining that we may enforce the major source permitting requirements in such cases when a source “circumvents” major source NSR by dividing one change and its emission increase into nominally-separate physical or operational changes. 6 Some of these letters discussed intent to evade NSR, but focused more on objective factors such as the closeness in the timing of nominally-separate changes and the integrated planning of these changes. 7 In 1993, we issued a letter analyzing a series of minor permit applications for 3M Company's research and development facility in Maplewood, Minnesota. 8 This letter has been widely cited for its discussion of objective factors that could support a conclusion that nominally-separate changes should be treated as one project. These factors include the filing of multiple minor source or minor modification permits for a single source within a short period of time, funding information indicating one project, other reporting on consumer demand and project levels, other statements from the business indicating one project, EPA's assessment of the economic realities of the project, as well as the relationship of the changes to the overall basic purpose of the plant. Subsequently, we have issued additional letters discussing aggregation at particular plants in certain circumstances. 9 Collectively, these letters outline an approach where we would look at case-specific facts and the relationship between nominally-separate changes to determine whether they were a single project to be assessed for an emission increase under Step 1 of the NSR applicability test.

The statute itself defines modification in the singular: “any physical change in, or change in the method of operation of, a stationary source” that increases emissions. Some have argued that we cannot aggregate or accumulate nominally-separate changes to determine NSR applicability because they can be viewed as multiple changes.

In response to this argument in comments on the NSR Aggregation Amendment proposed rule, we cited the recent decision in New York II, which held that the definition of modification requires “EPA [to] apply NSR whenever a source conducts an emission-increasing activity that fits within one of the ordinary meanings of `physical change.'  ” 443 F.3d at 885. Because “[s]ubstantially related, nominally-separate changes can be seen as one change when viewed as a whole,” we viewed “[a]ggregation of nominally separate changes that are substantially related as `fit[ting] within one of the ordinary meanings of physical change.' ”  10 Therefore, we viewed aggregation as allowed under the statute and the “substantially related” test for aggregation as a permissible interpretation of the modification definition.

Having seen EPA's analysis of New York II for the first time in the response-to-comment document supporting the NSR Aggregation Amendments, NRDC expressed the view that the foregoing analysis of that case “utterly misses the point.” NRDC's petition acknowledges that aggregation of nominally-separate changes that are substantially related is one of the ordinary meanings of physical change. However, NRDC notes that “aggregation of nominally separate changes that are not substantially related” also may be within an ordinary meaning of physical change, especially when substantially related is defined in terms of technical or economic interrelationship and dependence. In NRDC's view, because the statute covers “any physical change,” and the NSR Aggregation Amendments would omit some of these physical changes from NSR permitting by not aggregating them, the NSR Aggregation Amendments impermissibly narrowed the expansive reading of the statute's “any physical change” required by New York II. See NRDC petition at 5-6.

The issue NRDC raises goes to the crux of the NSR Aggregation Amendments. What must be treated as one physical or operational change under the definition of “modification” in the act is the legal underpinning for our aggregation policy.

The New York II Court held that we have limited authority to exempt from NSR those activities that can be considered a single physical change. Accordingly, “any physical change” should encompass any change that reasonably can be considered an ordinary meaning of the phrase. As the Court noted, “[W]hen Congress places the word `any' before a phrase with several common meanings, the statutory phrase encompasses each of those meanings; the agency may not pick and choose among them.” 443 F.3d at 888. The logic of New York II applies not only to physical changes but also to changes in the method of operation of a source.

Much of the emphasis of New York II and other cases has been on whether we could exclude small changes from being considered potential modifications as defined in the Act. However, the New York II Court's reasoning also applies to a rule that would split apart one change into separate changes in order to limit the applicability of NSR. The Court concludes, “[a]lthough the phrase “physical change” is susceptible to multiple meanings, the word “any” makes clear that activities within each of the common meanings of the phrase are subject to NSR when the activity results in an emission increase.” 443 F.3d at 890. The statute prohibits EPA from picking and choosing among meanings of the phrase “any physical change * * * or change in the method of operation” if it would result in omitting a common meaning that would subject an emission increase to review.

Historically, EPA has analyzed the question of whether nominally-separate changes are one change by using a case-by-case review of all relevant and objective factors that looks for “indicia,” or indicators, of these changes being one common aggregate change. As noted above, one much-cited example of our analysis of grouping together nominally-separate changes is appropriate is the “3M-Maplewood” memorandum discussed above and in the notices for the proposed and final rules. One concern about the 3M-Maplewood analysis has been that one portion of the analysis suggests that any set of nominally-separate changes that are consistent with “the plant's overall basic purpose” can be aggregated. 11

The opinion in New York II further clarifies this portion of the 3M-Maplewood analysis, which remains EPA's most complete statement of the principles regarding grouping nominally-separate changes. As the Court observed, “[t]he modifier `any' cannot bring an activity that is never considered a `physical change' within the ambit of NSR.” 443 F.3d at 887-888. Therefore, an important limiting factor in analyzing indicia of whether nominally-separate changes should be grouped into an aggregated, single change is whether the grouping would be under one of the ordinary meanings of physical change or change in the method of operation of a source.

If “substantially related” would omit an ordinary, common meaning of physical change that would bring an emission-increasing project under review, then the definition would eliminate a type of physical change that Congress intended to cover ( i.e., the change that consists of the group of nominally-separate changes that comprise a project but do not qualify as “substantially related”). In effect, the interpretation in the NSR Aggregation Amendments is unreasonable because it would create a carve-out from the scope of the statutory definition of modification.

It is our view that New York II requires EPA to aggregate any group of small changes that are sufficiently related to “fit[] within one of the ordinary meanings of ‘physical change.’ ” We agree with the contention that, to the extent that our “substantially related” interpretation would exclude meanings that fit within a reasonable understanding of the ordinary meaning of “any physical change,” the interpretation in the NSR Aggregation Amendments would impermissibly narrow the scope of CAA section 111(a)(4). We seek comment on our analysis.

We specifically invite comment on the following questions. Do we have the authority to aggregate nominally-separate changes that “fit within one of the ordinary meanings” of a single physical or operational change when they are viewed in the context of the source? Is New York II relevant to the question of whether we aggregate? Are there “ordinary meanings” of physical or operational change that do not fit within “substantially related” as we describe it in the NSR Aggregation Amendments? Do we have the authority to exclude these meanings in light of the New York II language?

In one respect, the aggregation of nominally-separate changes that are “substantially related” appears to be distinguishable from the legal error underlying the rule at issue in New York II, the “Equipment Replacement Provision” or “ERP”. In the ERP, we claimed that the excluded activities ( e.g., replacements that were functionally equivalent and less than 20 percent of the replacement cost) were not physical changes as meant by the statute. In the NSR Aggregation Amendments, we recognize that a nominally-separate physical or operational change is a change by itself and declare it not to be part of a “larger change”  12 that also meets a common understanding of a single “change.” To the extent that one event could be a part of either a change that is smaller or a change that is larger, one may argue that it is ambiguous as to which meaning of change should apply.

We are not persuaded that the same event possibly being part of more than one change is an ambiguity that would allow us to exclude the event from CAA section 111(a)(4). The New York II decision requires that, when choosing among meanings of “change” in various contexts, we must choose a meaning that brings the emission-increasing change into the potential scope of the modification definition. Therefore, we do not consider the potential for a nominally-separate change to be either a change by itself or a change that is part of a larger change to be an ambiguity that would allow us to select the less inclusive meaning. Nevertheless, were a reviewing court to find that there is some ambiguity in the statute as it applies to the coverage of nominally-separate changes, we believe there may be policy concerns that would warrant revocation of the NSR Aggregation Amendments.

An objection raised in NRDC's petition is that the EPA's 2006 proposal on Aggregation failed to identify any actual problems or inconsistencies with longstanding aggregation policy as applied and explained in the 3M Maplewood letter. While the issue of whether the historic policy on project aggregation had problems was raised by our proposed rule, we did not request comment on the various factors we historically applied. Given that we now view the state of the record differently, we are taking this opportunity to request comment on the need for a change in policy.

The impetus for developing the NSR Aggregation Amendments emerged from a study conducted by EPA in 2001 on the impact of NSR regulations on investment in new utility and refinery generation. This EPA study took input from a range of stakeholders and resulted in a report to the President in 2002 that included a suite of recommendations for how to change the NSR rules to improve the effectiveness of the program. One of the recommendations was for EPA to make clarifying changes to the approach used for aggregating projects.

However, in reviewing the record for the NSR Aggregation Amendments, we find that the only factual support for the contention that our historic approach caused confusion was anecdotal. The parties supporting a change in policy failed to provide us with any characterization of the overall level of uncertainty or other problems resulting from the existing policy on aggregation. Furthermore, through our Aggregation proposal in 2006, we received countervailing testimony from permitting agencies and other stakeholders that contended that there was little confusion in the application of our aggregation policy. For example, the State of New Mexico wrote that “* * * the current common sense approach of looking at the timing, scope, and interrelationship(s) of projects in determining the occurrence of aggregation is more straightforward than to narrowly evaluate the validity of independent economic justification * * * or technical dependence of various projects.”  13 We also heard from a local reviewing authority in Ohio, who recommended that “* * * EPA propose a test that more accurately represents current permitting authority practice with regard to evaluating major NSR applicability and aggregation.”  14 Finally, the National Association of Clean Air Agencies stated that the proposal left “* * * greater uncertainty than the previous, reasonably well-developed policy.”  15 We note that these comments were made in the context of a proposed rule based on technical and economic dependence, not “substantially related,” but nevertheless illustrate a basic comfort level with the current practice.

We request comment on whether there was a bona fide need for added clarity over and above what the old aggregation policy provided. If clarity was lacking, we further solicit comment on whether the NSR Aggregation Amendments achieved added clarity.

We also note that it has been our experience that the few applicability determinations we have issued where aggregation was the central issue have not been contested on appeal. The absence of contested applicability determinations tends to support a belief that there was not significant confusion or controversy with our historic policy. Through this reconsideration, we specifically request comment from reviewing authorities on the frequency of disputes with other parties over their aggregation decisions, such as appeals of applicability determinations where this has been an issue, adverse comments in permitting proceedings, or having to brief the issue in litigation.

As noted above, the NSR Aggregation Amendments did not include amendatory text for the Code of Federal Registers (CFR). We agree with NRDC's assertion that the state and local implementation requirements of the NSR Aggregation Amendments are unclear. The question of whether a SIP amendment is required when the CFR remains unchanged is likely to cause confusion for reviewing authorities and other stakeholders. We view these difficulties as clear support for the need to have the rule not be effective until the completion of our reconsideration proceeding. We also view it as added support for our preferred position in this notice, which is to revoke the NSR Aggregation Amendments, as discussed in greater detail in the next section of this notice.

In section III.3.a of this notice, we ask for comment on whether the existing NSR regulatory text can support the new interpretation provided by the NSR Aggregation Amendments if the rule remains in effect after this reconsideration proceeding. Apart from this important question, we are also taking comment on when and how reviewing authorities with EPA-approved plans in 40 CFR part 51.166 can implement the new policy interpretation given that there are no CFR changes to use as a basis for drafting amendments to their state plans.

In a broader sense, when EPA issues an interpretive rule, have reviewing authorities with EPA-approved implementation programs adopted the new interpretation in their implementation plans? Or have these agencies not required a plan amendment and immediately applied the new interpretation? If a plan revision was required, what was the proper mechanism for State adoption for an interpretive rule where there is no change to the CFR? We solicit comment on all of these questions.

As part of NRDC's petition requesting reconsideration of the Aggregation Amendments, NRDC further asked EPA to “withdraw and abandon the final rule.” While rare, the Administrator has in the past withdrawn, or revoked, a promulgated rule prior to its effective date. The reasons for such action by the Administrator are varied, but typically it is done when a final rule is determined to be either error prone, confusing, overly burdensome, or unnecessary, such that leaving the rule in place would not improve the program. 16

An overarching concern of EPA is that our original policy goal for developing the Aggregation Amendments— i.e., to provide improved clarity in making aggregation determinations—does not appear to have been achieved. This concern is reflected in the petition for reconsideration, and we believe it has sufficient merit that we must consider whether retaining the NSR Aggregation Amendments is justified. While the rule may, in some respects, appear clearer than our past policy, we are not convinced that it achieved enough additional clarity to improve the process of making aggregation assessments by sources and reviewing authorities. As noted above, our reexamination of the record also leads us to believe that the apparent need for additional clarity with the aggregation policy may have been overstated. Furthermore, as discussed above, the rule introduces new ambiguities, particularly with respect to implementation, that may further reduce its effectiveness.

Balancing this against the additional issues raised with respect to the legal and implementation aspects of the final rule, as well as our concern of possible under-inclusiveness of the final rule ( i.e., the chance that certain projects that should be aggregated would avoid aggregation under the approach from the NSR Aggregation Amendments), we believe that the prior agency policy may, on balance, provide a more reasonable interpretation than the policy interpretation contained in the final rule. We are therefore proposing as our preferred option to revoke the final rule. If we ultimately decide through reconsideration to revoke the NSR Aggregation Amendments, we believe we should restore the past policy for making case-by-case aggregation determinations.

We specifically solicit comment on the legal concerns and possible under-inclusiveness with the final rule. As noted above, comments received on our proposal from various reviewing authorities show some support for retaining the pre-existing aggregation factors. Thus, we also request comment on whether the old policy framework for aggregating nominally-separate changes is adequate if the NSR Aggregation Amendments is revoked. Has the decision in New York II helped to improve the understanding of the past policy direction in 3M-Maplewood and other relevant memoranda?

As noted, the effective date of the NSR Aggregation Amendments is May 18, 2010. This scheduled date was shifted from the original effective date to allow time for the Agency to conduct a full reconsideration of the final rule.

We are concerned now, however, that our reconsideration rulemaking schedule will not meet the revised effective date. Furthermore, we still have concerns, as noted above, with the final rule becoming effective prior to completion of our reconsideration proceeding. Recognizing this, we are proposing additional time that would enable us to fully evaluate comments on issues that are in question and to complete any revisions of the rule that become necessary as a result of the reconsideration process, without the concern of the rule prematurely becoming effective.

Therefore, we propose to delay the effective date of the NSR Aggregation Amendments, published in the Federal Register on January 15, 2009 (74 FR 2376), until November 18, 2010. This delay would be for an additional 6 months, which we believe would provide a reasonable period of time to complete action on the reconsideration. We solicit comment on a 6-month delay of the effectiveness of the final rule, and we also solicit comment on a longer delay ( e.g., 9 or 12 months).

Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is a “significant regulatory action” because it raises novel legal or policy issues. Accordingly, EPA submitted this action to the Office of Management and Budget (OMB) for review under EO 12866 and any changes made in response to OMB recommendations have been documented in the docket for this action.

This action does not impose any new information collection burden. We are not proposing any new paperwork requirements ( e.g., monitoring, reporting, recordkeeping) as part of this proposed action. This action simply solicits comment on a number of legal and policy issues raised in a petition for reconsideration on the NSR Aggregation Amendments, and proposes an additional extension of the stay of the rule.

However, the OMB has previously approved the information collection requirements contained in the existing regulations (40 CFR parts 51 and 52) under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., and has been assigned OMB control number 2060-0003. The OMB control numbers for EPA's regulations in 40 CFR are listed in 40 CFR part 9.

The Regulatory Flexibility Act (RFA) generally requires an agency to prepare a regulatory flexibility analysis of any rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or any other statute unless the agency certifies that the rule will not have a significant economic impact on a substantial number of small entities. Small entities include small businesses, small organizations, and small governmental jurisdictions.

For purposes of assessing the impacts of this proposal on small entities, small entity is defined as: (1) A small business as defined by the Small Business Administration's (SBA) regulations at 13 CFR 121.201; (2) a small governmental jurisdiction that is a government of a city, county, town, school district or special district with a population of less than 50,000; and (3) a small organization that is any not-for-profit enterprise which is independently owned and operated and is not dominant in its field.

After considering the economic impacts of this proposed rule on small entities, I certify that this action will not have a significant economic impact on a substantial number of small entities. This proposed rule will not impose any new requirements on small entities. We have determined that small businesses will not incur any adverse impacts because no costs were associated with the NSR Aggregation Amendments, and this proposed reconsideration of that rule simply requests comment on a variety of issues, none of which would create any new requirements or burdens. Therefore, no costs are associated with this proposed amendment.

We continue to be interested in the potential impacts of the proposed rule on small entities and welcome comments on issues related to such impacts.

This action does not contain a federal mandate under the provisions of Title II of the Unfunded Mandates Reform Act of 1995 (“URMA”), 2 U.S.C. 1531-1538 for state, local, and tribal governments or the private sector. This action simply solicits comment on a number of issues raised in a petition for reconsideration on the NSR Aggregation Amendments, and proposes to revoke the rule. Therefore, this action is not subject to the requirements of sections 202 or 205 of UMRA.

This action is also not subject to the requirements of section 203 of UMRA because it contains no regulatory requirements that might significantly or uniquely affect small governments.

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132. This action simply solicits comment on issues raised in NRDC's petition for reconsideration on the NSR Aggregation Amendments, and proposes to revoke the rule. Thus, Executive Order 13132 does not apply to this proposed rule.

In the spirit of Executive Order 13132, and consistent with EPA policy to promote communications between EPA and state and local governments, EPA specifically solicits comment on this proposed rule from state and local officials.

This action does not have tribal implications, as specified in Executive Order 13175 (65 FR 67249, November 9, 2000.) This action will not impose any new obligations or enforceable duties on tribal governments.

EPA specifically solicits additional comment on this proposed action from tribal officials.

This action is not subject to EO 13045 (62 FR 19885), April 23, 1997) because the Agency does not believe the environmental health or safety risks addressed by this action present a disproportionate risk to children. We do not believe this action creates any environmental health or safety risks.

The public is invited to submit comments or identify peer-reviewed studies and data that assess effects of early life exposure.

This action is not a “significant energy action” as defined under Executive Order 13211, “Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355, May 22, 2001) because it is not likely to have a significant adverse effect on the supply, distribution, or use of energy. This action will not create any new requirements for sources in the energy supply, distribution, or use sectors.

Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (“NTTAA”), Public Law 104-113, 12(d) (15 U.S.C. 272 note) directs EPA to use voluntary consensus standards in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards are technical standards ( e.g., materials specifications, test methods, sampling procedures, and business practices) that are developed or adopted by voluntary consensus standards bodies. NTTAA directs EPA to provide Congress, through OMB, explanations when the Agency decides not to use available and applicable voluntary consensus standards.

This proposed rulemaking does not involve technical standards. Therefore, EPA is not considering the use of any voluntary consensus standards.

Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes Federal executive policy on environmental justice. Its main provision directs Federal agencies, to the greatest extent practicable and permitted by law, to make environmental justice part of their mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of their programs, policies, and activities on minority populations and low-income populations in the United States.

EPA has determined that this proposed rule will not have disproportionately high and adverse human health or environmental effects on minority or low-income populations because any impacts that it will have will be global in nature and will not affect local communities or populations in a manner that adversely affects the level of protection provided to human health or the environment.

Pursuant to sections 307(d)(1)(E) and 307(d)(1)(V) of the CAA, the Administrator determines that this action is subject to the provisions of section 307(d). Section 307(d)(1)(V) provides that the provisions of section 307(d) apply to “such other actions as the Administrator may determine.”

The statutory authority for this action is provided by section 301(a) of the CAA as amended (42 U.S.C. 7601(a)). This notice is also subject to section 307(d) of the CAA (42 U.S.C. 7407(d)).

Public Comments

We intend that any final action resulting from the proposed rule is based on the best scientific data available and will be accurate and as effective as possible. Therefore, we request comments or information from other concerned government agencies, the scientific community, industry, or any other interested parties during this reopened comment period on our proposed rule to revise critical habitat for Navarretia fossalis (spreading navarretia), which we published in the Federal Register on June 10, 2009 (74 FR 27588), including the changes to proposed critical habitat in Subunits 1A, 1B, 3B, 5C, 5I, 6A, 6B, and 6C, the DEA of the proposed revised designation, and the amended required determinations provided in this document. We are particularly interested in comments concerning:

(1) The reasons why we should or should not revise the critical habitat under section 4 of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq. ), including whether there are threats to Navarretia fossalis from human activity, the type of human activity causing these threats, and whether the benefit of designation would outweigh any threats to the species caused by the designation, such that the designation of critical habitat is prudent.

(2) Specific information on:

• The current amount and distribution of Navarretia fossalis habitat.

• Areas that provide habitat for N. fossalis that we did not discuss in our original proposed revised critical habitat rule or in this reopening of the comment period.

• Areas containing the physical and biological features essential to the conservation of N. fossalis that we should include in the revised critical habitat designation and why. Include information on the distribution of these essential features and what special management considerations or protections may be required to maintain or enhance them.

• Areas proposed as critical habitat that do not contain the physical and biological features essential for the conservation of the species that should not be designated as critical habitat.

• Areas not occupied at the time of listing that are essential to the conservation of the species and why.

(3) Land use designations and current or planned activities in the areas occupied by the species, and their possible impacts on proposed critical habitat;

(4) How the proposed revised critical habitat boundaries could be refined to more closely circumscribe landscapes identified as containing the physical and biological features essential to the conservation of the species.

(5) Any foreseeable economic, national security, or other relevant impacts that may result from designating particular areas as critical habitat, and, in particular, any impacts to small entities (e.g., small businesses or small governments), and the benefits of including or excluding areas from the proposed revised designation that exhibit these impacts.

(6) Special management considerations or protections that the essential physical and biological features identified in the proposed critical habitat may require.

(7) Information on the extent to which the description of potential economic impacts in the DEA is complete and accurate.

(8) Whether any specific subunits being proposed as critical habitat should be excluded under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any particular area outweigh the benefits of including that area as critical habitat.

(9) Our consideration to exclude the portion of Subunit 4E that we are proposing as critical habitat within the Ramona Grasslands Preserve under section 4(b)(2) of the Act, and whether such exclusion is appropriate and why;

(10) The likelihood of adverse social reactions to the designation of critical habitat, and how the consequences of such reactions, if they occur, would relate to the conservation of the species and regulatory benefits of the proposed revised critical habitat designation.

(11) Information on the extent to which the description of potential economic impacts in the DEA is complete and accurate, and specifically:

• Whether there are incremental costs of critical habitat designation (e.g., costs attributable solely to the designation of critical habitat for Navarretia fossalis ) that have not been appropriately identified or considered in our economic analysis, including costs associated with future administrative costs or project modifications that may be required by Federal agencies related to section 7 consultation under the Act;

• Whether there are incremental economic benefits of critical habitat designation that have not been appropriately identified or considered in our economic analysis.

(12) The potential effects of climate change on this species and its habitat and whether the critical habitat may adequately account for these potential effects.

If you submitted comments or information on the proposed revised rule (74 FR 27588) during the initial comment period from June 10, 2009, to August 10, 2009, please do not resubmit them. These comments are included in the public record for this rulemaking, and we will fully consider them in the preparation of our final determination. Our final determination concerning the revised critical habitat for Navarretia fossalis will take into consideration all written comments and any additional information we receive during both comment periods. On the basis of public comments, we may, during the development of our final determination, find that areas within the proposed revised critical habitat designation do not meet the definition of critical habitat, that some modifications to the described boundaries are appropriate, or that areas may or may not be appropriate for exclusion under section 4(b)(2) of the Act.

You may submit your comments and materials concerning our proposed rule, the associated DEA, our changes to subunits and considered exclusions as identified in this document, and our amended required determinations section by one of the methods listed in the ADDRESSES section.

If you submit a comment via http://www.regulations.gov , your entire submission—including any personal identifying information—will be posted on the website. If your submission is made via a hard copy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hard copy comments on http://www.regulations.gov . Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.

Comments and materials we receive, as well as supporting documentation used to prepare this notice, will be available for public inspection at http://www.regulations.gov , or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ). You may obtain copies of the proposed revision of critical habitat (74 FR 27588) and the DEA on the Internet at http://www.regulations.gov at Docket No. FWS-R8-ES-2009-0038, or by mail from the Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).

It is our intent to discuss only those topics directly relevant to the proposed revised designation of critical habitat for Navarretia fossalis in this notice. For more information on previous Federal actions concerning N. fossalis , see the 2005 final designation of critical habitat published in the Federal Register on October 18, 2005 (70 FR 60658), or the 2009 proposed revised designation of critical habitat published in the Federal Register on June 10, 2009 (74 FR 27588), or contact the Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).

The Center for Biological Diversity filed a complaint in the U.S. District Court for the Southern District of California on December 19, 2007, challenging our designation of critical habitat for Navarretia fossalis and Brodiaea filifolia ( Center for Biological Diversity v. United States Fish and Wildlife Service et al ., Case No. 07-CV-2379-W-NLS). This lawsuit challenged the validity of the information and reasoning we used to exclude areas from the 2005 critical habitat designation for N. fossalis . We reached a settlement agreement on July 25, 2008, in which we agreed to reconsider critical habitat designation for N. fossalis . The settlement stipulated that we submit a proposed revised critical habitat designation for N. fossalis to the Federal Register for publication by May 29, 2009, and submit a final revised critical habitat designation to the Federal Register for publication by May 28, 2010. On June 10, 2009, we published the revised proposed critical habitat designation in the Federal Register (74 FR 27588). On January 20, 2010, we were granted an extension to submit a final revised critical habitat designation to the Federal Register for publication by September 30, 2010.

Section 3 of the Act defines critical habitat as the specific areas within the geographical area occupied by a species, at the time it is listed in accordance with the Act, on which are found those physical or biological features essential to the conservation of the species and that may require special management considerations or protection, and specific areas outside the geographical area occupied by a species at the time it is listed, upon a determination that such areas are essential for the conservation of the species. If the proposed rule is made final, section 7 of the Act will prohibit destruction or adverse modification of critical habitat by any activity funded, authorized, or carried out by any Federal agency. Federal agencies proposing actions affecting critical habitat must consult with us on the effects of their proposed actions, under section 7(a)(2) of the Act.

Section 4(b)(2) of the Act requires that we designate or revise critical habitat based upon the best scientific and commercial data available, after taking into consideration the economic impact, impact on national security, or any other relevant impact of specifying any particular area as critical habitat.

We prepared a DEA (Entrix, Inc. 2010), which identifies and analyzes the potential impacts associated with the proposed revised designation of critical habitat for Navarretia fossalis that we published in the Federal Register on June 10, 2009 (74 FR 27588). The DEA looks retrospectively at costs incurred since the October 13, 1998 (63 FR 54975), listing of N. fossalis as threatened. The DEA quantifies the economic impacts of all potential conservation efforts for N. fossalis ; some of these costs will likely be incurred regardless of whether or not we finalize the revised critical habitat rule. The economic impact of the proposed revised critical habitat designation is analyzed by comparing a “with critical habitat” scenario with a “without critical habitat” scenario. The “without critical habitat” scenario represents the baseline for the analysis, considering protections already in place for the species (for example, under the Federal listing and other Federal, State, and local regulations). The baseline, therefore, represents the costs incurred regardless of whether critical habitat is designated. The “with critical habitat” scenario describes the incremental impacts associated specifically with the designation of critical habitat for the species. The incremental conservation efforts and associated impacts are those not expected to occur absent the critical habitat designation for N. fossalis . In other words, the incremental costs are those attributable solely to the designation of critical habitat above and beyond the baseline costs; these are the costs we may consider in the final designation of critical habitat relative to areas that may be excluded under section 4(b)(2) of the Act. The analysis looks retrospectively at baseline impacts incurred since the species was listed, and forecasts both baseline and incremental impacts likely to occur if we finalize the proposed revised critical habitat.

The 2010 DEA (made available with the publication of this notice and referred to as the DEA throughout this document unless otherwise noted) estimates the foreseeable economic impacts of the proposed revised critical habitat designation for Navarretia fossalis . The economic analysis identifies potential incremental costs as a result of the proposed revised critical habitat designation, which are those costs attributed to critical habitat over and above those baseline costs coextensive with listing. It also discusses the benefits of critical habitat designation. These benefits are primarily presented in a qualitative manner. The DEA describes economic impacts of N. fossalis conservation efforts associated with the following categories of activity: (1) Development, (2) conservation lands management, (3) transportation, (4) pipeline projects, (5) flood control, (6) agriculture, and (7) fire management.

Baseline economic impacts are those impacts that result from listing and other conservation efforts for Navarretia fossalis . Conservation efforts related to flood control and development activities constitute the majority of total baseline costs (approximately 84 percent of post-designation, upper-bound, baseline impacts when a 7 percent discount rate is used) in areas of proposed revised critical habitat. Impacts to conservation lands management, transportation, and pipeline projects compose the remaining approximately 16 percent of post-designation, upper-bound, baseline impacts when a 7 percent discount rate is used. Total future baseline impacts are estimated to be $30.1 to $123.5 million ($2.9 to $11.7 million annualized) in present value terms using a 7 percent discount rate, over the next 20 years (2010-2029) in areas proposed as revised critical habitat (Entrix, Inc. 2010, pp. ES-3-ES-4).

Conservation costs associated with section 7 consultations for development, transportation, and flood control projects comprise the quantified incremental impacts for the proposed revised critical habitat rule. Impacts associated with transportation constituted the largest portion of post-designation, upper-bound incremental impacts, accounting for almost 47 percent of the forecast incremental impacts applying a 7 percent discount rate. Conservation efforts related to development and flood control activities constitute the remainder of incremental impacts (37 percent and 16 percent, respectively, of post-designation upper-bound baseline impacts when a 7 percent discount rate is used) in areas of proposed revised critical habitat. The DEA estimated total potential incremental economic impacts in areas proposed as revised critical habitat over the next 20 years (2010-2029) to be $846,000 to $1.2 million ($80,000 to $100,000 annualized) in present value terms applying a 7 percent discount rate (Entrix, Inc. 2010, pp. ES-3-ES-4).

The DEA considers both economic efficiency and distributional effects. In the case of habitat conservation, efficiency effects generally reflect the “opportunity costs” associated with the commitment of resources to comply with habitat protection measures (such as lost economic opportunities associated with restrictions on land use). The DEA also addresses how potential economic impacts are likely to be distributed, including an assessment of any local or regional impacts of habitat conservation and the potential effects of conservation activities on government agencies, private businesses, and individuals. The DEA measures lost economic efficiency associated with residential and commercial development and public projects and activities, such as economic impacts on water management and transportation projects, Federal lands, small entities, and the energy industry. Decision-makers can use this information to assess whether the effects of the revised designation might unduly burden a particular group or economic sector.

In this document we are proposing revisions to Subunits 1A, 1B, 3B, 5I, 6A, 6B, and 6C, as identified and described in the revised proposed rule that published in the Federal Register on June 10, 2009 (74 FR 27588), and adding a new Subunit 5C. We received comments from the public and from one peer reviewer during the open comment period indicating that we should reevaluate the proposed boundaries of Subunits 1A, 1B, 3B, 5I, 6A, 6B, and 6C and that we should include subunit 5C in the proposed critical habitat. The purpose of the revisions described below is to better delineate the areas that meet the definition of critical habitat for Navarretia fossalis . All areas added to the units proposed in the June 10, 2009 (74 FR 27588), proposed rule are within the geographic range occupied by the species at the time it was listed and contain the features essential for the conservation of the species. These areas contain the primary constituent elements (PCEs), which are the physical or biological features essential to the conservation of a species, and which the species' proposed or designated critical habitat is based on, such as space for individual and population growth, and for normal behavior; food, water, air, light, minerals, or other nutritional or physiological requirements; cover or shelter; sites for breeding, reproduction, rearing of offspring, germination, or seed dispersal; and habitats that are protected from disturbance or are representative of the species' historic geographic and ecological distribution.

The revisions consist of both additions and removals of land that we proposed as critical habitat (74 FR 27588). The changes made in Subunits 1A, 1B, 3B, 5I, 6A, 6B, and 6C do not alter the description of these subunits in the June 10, 2009, proposed rule (74 FR 27588); however, we include revised maps with this publication. We briefly describe the changes made for each of these subunits below. We did not include Subunit 5C in the proposed rule (74 FR 27588, June 10, 2009), so this notice includes the full description and map for Subunit 5C below. As a result of these revisions, the overall area proposed for critical habitat is 7,609 acres (ac) (3,079 hectares (ha)), an increase of 737 ac (298 ha) from the 6,872 ac (2,781 ha) that we proposed as critical habitat in the June 10, 2009, proposed rule (74 FR 27588). A summary of the total acreage of each proposed subunit is presented in Table 1.

We received comments indicating that we did not capture the entire watershed area necessary to fill the vernal pools supporting Navarretia fossalis in Subunit 1A. We reviewed aerial imagery and topographic maps for this area and verified that the subunit needed revision to adequately capture areas that meet the definition of critical habitat and include the watershed for the ponding areas on Cruzan Mesa (PCE 2). The revised subunit consists of 156 ac (63 ha) of private land, an increase of 27 ac (11 ha) from what we proposed as critical habitat in the June 10, 2009, proposed rule (74 FR 27588).

We received information indicating that the placement of our proposed critical habitat for Subunit 1B did not capture the vernal pool where Navarretia fossalis occurs in the Plum Canyon area. Due to a publication error, the incorrect map was published in the June 10, 2009, proposed rule (74 FR 27588). In reviewing this subunit, we became aware of more accurate data describing this area (Glenn Lukos Associates 2009, Exhibit 3 (Appendix D-3 of PCR 2009)). As a result of our evaluation of this new information, we remapped the boundaries of Subunit 1B. Our remapping corrects our publication error and incorporates the new information. Subunit 1B contains physical and biological features that are essential to the conservation of N. fossalis , including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The revised subunit consists of 20 ac (8 ha) of private land, a decrease of 12 ac (5 ha) from what we proposed in the June 10, 2009, proposed rule (74 FR 27588).

We received information indicating that the western portion of Subunit 3B had been graded and does not likely contain the physical and biological features essential to the conservation of Navarretia fossalis . We reviewed aerial imagery and found this information to be correct; therefore, we removed 2 ac (1 ha) of land that no longer meets the definition of critical habitat for this species. The revised subunit consists of 18 ac (7 ha) (16 ac (6 ha) of land owned by the City of San Diego and 2 ac (1 ha) of private land), a decrease of 2 ac (1 ha) from what we proposed in the June 10, 2009, proposed rule (74 FR 27588).

We received information from the public that we should propose Subunit 5C, a subunit that was designated as critical habitat in our October 18, 2005, final rule (70 FR 60658), as revised critical habitat in this rule. We did not include Subunit 5C in the proposed rule (74 FR 27588, June 10, 2009) because we did not have data in our GIS database indicating this area was occupied by Navarretia fossalis . We subsequently reviewed the data in our files on N. fossalis in Subunit 5C (the J26 vernal pool complex) and found records of N. fossalis occupancy (The Environmental Trust 2001, p. 1; 2000, p. 1). Based on this new information and because this vernal pool complex is also considered one of the best examples of vernal pool habitat on Otay Mesa (The Environmental Trust 2002, p. 2), we are proposing Subunit 5C as revised critical habitat. We have mapped the boundary of this subunit to conform to our current mapping methodology.

Subunit 5C is located on eastern Otay Mesa in San Diego County, California. This subunit is on the far eastern side of Otay Mesa north of Alta Road and south of Lower Otay Reservoir. Subunit 5C consists of 42 ac (17 ha), including 26 ac (11 ha) of State and local government-owned land and 16 ac (6 ha) private land. This subunit meets our criteria for satellite habitat; it supports a stable occurrence of Navarretia fossalis and provides potential connectivity between occurrences of N. fossalis in Subunits 5G and 5I. Subunit 5C contains the physical and biological features that are essential to the conservation of N. fossalis , including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species, altered hydrology, and human disturbance activities (e.g., unauthorized grazing activity) that occur in the vernal pool basins and associated watershed. Please see the “Special Management Considerations or Protection” section of the proposed rule for a discussion of the threats to N. fossalis habitat and potential management considerations (74 FR 27588, June 10, 2009).

We are not proposing to revise the boundaries of Subunit 5I; however, due to a publication error, we are providing the correct map for Subunit 5I in this document. For clarification, we reiterate that Subunit 5I consists of 221 ac (89 ha) of private land as described in the June 10, 2009, proposed rule (74 FR 27588).

We received information from the public that we had not included some additional areas that meet the definition of critical habitat for Navarretia fossalis in Subunit 6A. We reviewed the new information provided, including a 2005 map that provided better survey data along the San Jacinto River (Helix Environmental, Inc. 2005, map). Based on the new information, we included additional areas in this subunit that meet the definition of critical habitat for N. fossalis . We expanded the critical habitat designation boundary for Subunit 6A in the following areas: (1) Around 13th Street to the east of the San Jacinto River, (2) east to Dawson Road and north to Ellis Road near Simpson Road, (3) around the Case Road vernal pool, and (4) north of the Green Valley Parkway. The revised subunit consists of 4,312 ac (1,745 ha) of private land, an increase of 762 ac (308 ha) from what we proposed in the June 10, 2009, proposed rule (74 FR 27588).

A peer reviewer recommended that we revise the boundaries of the proposed critical habitat in three areas of Subunit 6B, because we had included areas that were disturbed by past activities and no longer meet the definition of critical habitat and had not included some areas that meet the definition of critical habitat for Navarretia fossalis . Following evaluation of this area in greater detail, we agreed with the peer reviewer and made changes to this subunit in the central portion on the east side, on the north end, and near the Hemet Airport. We are no longer proposing an area near the center on the east side that was developed and disturbed many years ago, has not supported N. fossalis since 1990, and therefore no longer meets the definition of critical habitat. Also, we are no longer proposing some land in the northern portion of the proposed subunit because it is dry, disturbed, and does not meet the definition of critical habitat for N. fossalis . Finally, we included vernal pool habitat on the eastern edge of our proposed subunit near the Hemet Airport that meets the definition of critical habitat for N. fossalis . The revised subunit consists of 943 ac (382 ha) of private land, a decrease of 111 ac (45 ha) from what we proposed in the June 10, 2009, proposed rule (74 FR 27588).

We received information that we had not adequately captured the physical and biological features essential to the conservation of Navarretia fossalis in Subunit 6C. We received new information describing the Wickerd Road vernal pool (Roberts 2009, p. 1). We reviewed the new information, including the information about the vernal pool and newer aerial imagery for this area. As a result, we revised the subunit to include the upward sloping area between the Wickerd Road vernal pool and Scott Road that meets the definition of critical habitat for N. fossalis and contributes to the watershed of this vernal pool. The revised subunit consists of 235 ac (95 ha) of private land, an increase of 30 ac (12 ha) from what we proposed in the June 10, 2009, proposed rule (74 FR 27588).

In the proposed revised critical habitat designation published on June 10, 2009 (74 FR 27588), we identified lands in Subunit 4E as meeting the definition of critical habitat for Navarretia fossalis . Based on comments submitted during the initial public comment period from June 10, 2009, to August 10, 2009, we are also considering for exclusion from critical habitat under section 4(b)(2) of the Act the portion of Subunit 4E within the Ramona Grasslands Preserve. Of the 135 ac (55 ha) proposed in Subunit 4E, 51 ac (21 ha) are part of the Ramona Grasslands Preserve, which is owned by the Nature Conservancy and San Diego County, and managed by San Diego County Department of Parks and Recreation. The Ramona Grasslands Preserve is covered by a conservation easement and being managed and monitored according to the “Area Specific Management Directives for the Ramona Grasslands Preserve” drafted by San Diego County (2007). The management plan for the Ramona Grasslands Preserve provides for the conservation of N. fossalis and its habitat through vernal pool management goals, including: managing nonnative invasive plant species, maintaining the vernal pool hydrology, and managing grazing activities to benefit vernal pool habitat (Conservation Biology Institute 2007, pp. 26-27, 31-34). This area will be incorporated into the North County Multiple Species Conservation Plan (North County MSCP) upon completion of that plan (San Diego County 2009).

As we stated earlier, we request data and comments from the public on the DEA, on all aspects of the proposed revised critical habitat rule (including the changes to proposed critical habitat in Subunits 1A, 1B, 3B, 5C, 5I, 6A, 6B, and 6C), and our amended required determinations. The final revised rule may differ from the proposed revised rule based on new information we receive during the public comment periods. In particular, we may exclude an area from critical habitat if we determine that the benefits of excluding the area outweigh the benefits of including the area as critical habitat, provided the exclusion will not result in the extinction of the species.

In our proposed rule published in the Federal Register on June 10, 2009 (74 FR 27588), we indicated that we would defer our determination of compliance with several statutes and Executive Orders until the information concerning potential economic impacts of the designation and potential effects on landowners and stakeholders became available in the DEA. We have now made use of the DEA to make these determinations.

In this document, we affirm the information in our June 10, 2009, proposed rule (74 FR 27588) concerning Executive Order (E.O.) 12866 ( Regulatory Planning and Review ), E.O. 13132 (Federalism), E.O. 12988 (Civil Justice Reform), the Paperwork Reduction Act, the National Environmental Policy Act, and the President's memorandum of April 29, 1994, “Government-to-Government Relations with Native American Tribal Governments” (59 FR 22951). However, based on the DEA data, we are amending our required determinations concerning the Regulatory Flexibility Act (5 U.S.C. 601 et seq. ), E.O. 13211 (Energy Supply, Distribution, or Use), E.O. 12630 (Takings), and the Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq. ).

Under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. , as amended by the Small Business Regulatory Enforcement Fairness Act (SBREFA) of 1996), whenever an agency is required to publish a notice of rulemaking for any proposed or final rule, it must prepare and make available for public comment a regulatory flexibility analysis that describes the effect of the rule on small entities (i.e., small businesses, small organizations, and small government jurisdictions), as described below. However, no regulatory flexibility analysis is required if the head of an agency certifies the rule will not have a significant economic impact on a substantial number of small entities. Based on our DEA of the proposed revised designation, we provide our analysis for determining whether the proposed rule would result in a significant economic impact on a substantial number of small entities. Based on comments we receive, we may revise this determination as part of a final rulemaking.

According to the Small Business Administration, small entities include small organizations, such as independent nonprofit organizations; small governmental jurisdictions, including school boards and city and town governments that serve fewer than 50,000 residents; and small businesses (13 CFR 121.201). Small businesses include manufacturing and mining concerns with fewer than 500 employees, wholesale trade entities with fewer than 100 employees, retail and service businesses with less than $5 million in annual sales, general and heavy construction businesses with less than $27.5 million in annual business, special trade contractors doing less than $11.5 million in annual business, and agricultural businesses with annual sales less than $750,000. To determine if potential economic impacts to these small entities are significant, we considered the types of activities that might trigger regulatory impacts under this designation as well as types of project modifications that may result. In general, the term significant economic impact is meant to apply to a typical small business firm's business operations.

To determine if the proposed revised designation of critical habitat for Navarretia fossalis would affect a substantial number of small entities, we consider the number of small entities affected within particular types of economic activities, such as residential and commercial development. In order to determine whether it is appropriate for our agency to certify that this rule would not have a significant economic impact on a substantial number of small entities, we considered each industry or category individually. In estimating the numbers of small entities potentially affected, we also considered whether their activities have any Federal involvement. Critical habitat designation will not affect activities that do not have any Federal involvement; designation of critical habitat affects activities conducted, funded, permitted, or authorized by Federal agencies.

If we finalize this proposed revised critical habitat designation, Federal agencies must consult with us under section 7 of the Act if their activities may affect designated critical habitat. Consultations to avoid the destruction or adverse modification of critical habitat would be incorporated into the existing consultation process because Navarretia fossalis is listed as a threatened species under the Act. In the 2010 DEA, we evaluated the potential economic effects on small business entities resulting from implementation of conservation actions related to the proposed revision to critical habitat for Navarretia fossalis . The analysis was based on the estimated incremental impacts associated with the proposed rulemaking as described in sections 3 through 10 of the DEA. The SBREFA analysis evaluated the potential for economic impacts related to several categories, including: (1) Residential, commercial and industrial development; (2) conservation lands management; (3) transportation; (4) pipeline projects; (5) flood control; (6) agriculture; and (7) fire management (Entrix, Inc. 2010, p. A-1). The DEA found that the only category of activity where the designation may impact small businesses is residential, commercial, and industrial development (Entrix, Inc. 2010, pp. A-1-A-4). For residential, commercial, and industrial development, the DEA estimated that there will be approximately 38 development projects in the areas proposed as critical habitat over the next 20 years. The total incremental impact to residential, commercial, and industrial development was estimated to be between $112,000 and $431,000 at a 7 percent discount rate over the next 20 years. On an annual basis this affects approximately two development related small businesses with a total annual impact ranging from $10,565 to $40,646 (Entrix, Inc. 2010, pp. A-3-A-4). In a regional context, there are approximately 500 small development related businesses in San Diego County and 303 in Riverside County. The 38 development related small businesses that may be impacted represent approximately 5 percent of the total number of development related small businesses in San Diego and Riverside Counties. We do not believe that this represents a substantial number of development-related small businesses or that an annual impact ranging from $10,565 to $40,646 is a significant economic impact; therefore, we do not find that the designation of critical habitat for N. fossalis will have a significant economic impact on a substantial number of small entities.

In summary, we considered whether the proposed revised designation would result in a significant economic impact on a substantial number of small entities. For the above reasons and based on currently available information, we certify that, if promulgated, the proposed revised critical habitat for Navarretia fossalis would not have a significant economic impact on a substantial number of small entities. Therefore, an initial regulatory flexibility analysis is not required.

On May 18, 2001, the President issued E.O. 13211 on regulations that significantly affect energy supply, distribution, and use. Executive Order 13211 requires agencies to prepare Statements of Energy Effects when undertaking certain actions. The OMB's guidance for implementing this Executive Order outlines nine outcomes that may constitute “a significant adverse effect” when compared to no regulatory action. As discussed in Appendix A, the DEA finds that none of these criteria are relevant to this analysis. The DEA concludes that no incremental impacts on the production, distribution, or use of energy are forecast associated specifically with this rulemaking. All forecast impacts are expected to occur associated with the listing of Navarretia fossalis , regardless of the designation of critical habitat. Therefore, designation of critical habitat is not expected to lead to any adverse outcomes (such as a reduction in electricity production or an increase in the cost of energy production or distribution), and a Statement of Energy Effects is not required.

In accordance with the Unfunded Mandates Reform Act, the Service makes the following findings:

(a) This rule will not produce a Federal mandate. In general, a Federal mandate is a provision in legislation, statute, or regulation that would impose an enforceable duty upon State, local, or Tribal governments, or the private sector, and includes both “Federal intergovernmental mandates” and “Federal private sector mandates.” These terms are defined in 2 U.S.C. 658(5)-(7). “Federal intergovernmental mandate” includes a regulation that “would impose an enforceable duty upon State, local, or Tribal governments,” with two exceptions. First, it excludes “a condition of federal assistance.” Second, it also excludes “a duty arising from participation in a voluntary Federal program,” unless the regulation “relates to a then-existing Federal program under which $500,000,000 or more is provided annually to State, local, and Tribal governments under entitlement authority,” if the provision would “increase the stringency of conditions of assistance” or “place caps upon, or otherwise decrease, the Federal Government's responsibility to provide funding” and the State, local, or Tribal governments “lack authority” to adjust accordingly. “Federal private sector mandate” includes a regulation that “would impose an enforceable duty upon the private sector, except (i) a condition of Federal assistance; or (ii) a duty arising from participation in a voluntary Federal program.”

Critical habitat designation does not impose a legally binding duty on non-Federal Government entities or private parties. Under the Act, the only regulatory effect is that Federal agencies must ensure that their actions do not destroy or adversely modify critical habitat under section 7. Designation of critical habitat may indirectly impact non-Federal entities that receive Federal funding, assistance, or permits, or that otherwise require approval or authorization from a Federal agency. However, the legally binding duty to avoid destruction or adverse modification of critical habitat rests squarely on the Federal agency. Furthermore, to the extent that non-Federal entities are indirectly impacted because they receive Federal assistance or participate in a voluntary Federal aid program, the Unfunded Mandates Reform Act would not apply, nor would critical habitat shift the costs of the large entitlement programs listed above on to State governments.

(b) As discussed in the DEA of the proposed revised designation of critical habitat for Navarretia fossalis , we do not believe that this rule would significantly or uniquely affect small governments because it would not produce a Federal mandate of $100 million or greater in any year; that is, it is not a “significant regulatory action” under the Unfunded Mandates Reform Act. The DEA concludes that incremental impacts may occur due to administrative costs of section 7 consultations for development, transportation, and flood control projects activities; however, these are not expected to affect small governments. Incremental impacts associated with these activities [jsc8]are expected to be borne by the Federal Government, California Department of Transportation, California Department of Fish and Game, Riverside County, Riverside County Flood Control and Water Conservation District, and City of Perris, which are not considered small governments. Consequently, we do not believe that the revised critical habitat designation would significantly or uniquely affect small government entities. As such, a Small Government Agency Plan is not required.

In accordance with E.O. 12630 (“Government Actions and Interference with Constitutionally Protected Private Property Rights”), we analyzed the potential takings implications of proposing revised critical habitat for Navarretia fossalis in a takings implications assessment. Critical habitat designation does not affect landowner actions that do not require Federal funding or permits, nor does it preclude development of habitat conservation programs or issuance of incidental take permits to permit actions that do require Federal funding or permits. The proposed revised critical habitat for N. fossalis does not pose significant takings implications for the above reasons.

A complete list of all references we cited in the proposed rule and in this document is available on the Internet at http://www.regulations.gov or by contacting the Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).

The primary authors of this notice are staff members of the Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).

Accordingly, we propose to further amend part 17, subchapter B of chapter I, title 50 of the Code of Federal Regulations, as proposed to be amended at 74 FR 27588, June 10, 2009, as set forth below.

1. The authority citation for part 17 continues to read as follows:

2. Critical habitat for Navarretia fossalis (spreading navarretia) in § 17.96(a), which was proposed for revision on June 10, 2009, at 74 FR 27620, is proposed to be further amended by:

a. Revising paragraph (5), including the index map of critical habitat units for Navarretia fossalis (spreading navarretia);

b. Revising paragraph (7)(ii), including the map of Subunits 1A (Cruzan Mesa) and 1B (Plum Canyon);

c. Revising paragraph (10)(ii), including the map of Subunit 3B (Carroll Canyon);

d. Redesignating paragraphs (19) through (27) as paragraphs (20) through (28);

e. Adding a new paragraph (19);

f. Revising newly designated paragraph (23)(ii), including the map of Subunit 5I (Eastern Otay Mesa Vernal Pool Complexes);

g. Revising newly designated paragraph (24)(ii), including the map of Subunit 6A (San Jacinto River);

h. Revising newly designated paragraph (25)(ii), including the map of Subunit 6B (Salt Creek Seasonally Flooded Alkali Plain); and

i. Revising newly designated paragraph (26)(ii), including the map of Subunit 6C (Wickerd and Scott Road Pools), to read as follows:

(a) Flowering plants.

(5) Note: Index Map of critical habitat units for Navarretia fossalis (spreading navarretia) follows:

Request for Information

To ensure that the status review is complete and based on the best available scientific and commercial information, and to provide an opportunity to all interested parties to provide information for consideration during the status review, we are requesting information concerning North American wolverines rangewide and in the contiguous United States. We are seeking:

(1) General information concerning the taxonomy, biology, ecology, genetics, and status of North American wolverines rangewide and in the contiguous United States.

(2) Specific information relevant to the consideration of a potential distinct population segment (DPS) of North American wolverines in the contiguous United States. This consideration will be guided by our Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act (16 U.S.C. 1531 et seq. ) (61 FR 4722, February 7, 1996) (known as the DPS Policy), which specifically considers two elements: (i) The discreteness of the population segment in relation to the remainder of the species to which it belongs; and (ii) the significance of the population segment to the species to which it belongs.

(3) Specific information on the conservation status of North American wolverines rangewide and in the contiguous United States, including information on distribution, abundance, and population trends.

(4) Specific information on threats to North American wolverines rangewide and in the contiguous United States, including: (i) The present or threatened destruction, modification, or curtailment of its habitat or range; (ii) overutilization for commercial, recreational, scientific, or educational purposes; (iii) disease or predation; (iv) the inadequacy of existing regulatory mechanisms; and (v) other natural or manmade factors affecting its continued existence.

(5) Specific information on implemented or planned conservation actions to improve wolverine habitats or decrease threats to wolverines in the contiguous United States.

(6) Specific information on the potential effects of climate change on wolverines, their habitat, and their food sources in the contiguous United States.

(7) Information on the management of wolverines on both sides of the international boundary where populations occur and how this management may differ between Canada and the United states in how it affects the status of wolverines.

If you submit information, we request you support it with documentation, such as data, maps, bibliographic references, methods used to gather and analyze the data, or copies of any pertinent publications, reports, or letters by knowledgeable sources.

Submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination. Section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or threatened species must be made “solely on the basis of the best scientific and commercial data available.”

You may submit your information concerning this status review by one of the methods listed in the ADDRESSES section. If you submit information via http://www.regulations.gov , your entire submission—including any personal identifying information—will be posted on the website. We will also post all hardcopy submissions on http://www.regulations.gov. If you include personal identifying information in your hardcopy submission, you may request at the top of your document that we withhold this personal identifying information from public review. However, we cannot guarantee that we will be able to do so.

Information and supporting documentation that we receive and use in preparing a finding will be available for you to review by appointment during normal business hours at the U.S. Fish and Wildlife Service, Montana Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT ).

The North American wolverine ( Gulo gulo luscus ) is the largest terrestrial member of the family Mustelidae. Adult males weigh 12 to 18 kilograms (kg) (26 to 40 pounds (lb)), and adult females weigh 8 to 12 kg (17 to 26 lb) (Banci 1994, p. 99). The wolverine resembles a small bear with a bushy tail. It has a broad, rounded head; short, rounded ears; and small eyes. Each foot has five toes with curved, semi-retractile claws used for digging and climbing (Banci 1994, p. 99).

Wolverines exist in alpine and sub-alpine habitats, which in the contiguous 48 States occur at high elevations in the Rocky, North Cascade, and Sierra Nevada mountains (Aubry et al. 2007, p. 2153). Wolverines have recently been positively documented in the Sierra Nevada range in California and the southern Rocky Mountains of Colorado for the first time since the early 20th century.

Wolverines are opportunistic feeders and consume a variety of foods depending on availability. They primarily scavenge carrion, but also prey on small animals and birds, and eat fruits, berries, and insects (Hornocker and Hash 1981, p. 1290; Hash 1987, p. 579; Banci 1994, pp. 111-113).

Wolverines have delayed onset of reproduction in females and small litter sizes, and often reproduce only every other year.

Home ranges at the southern terminus of the current range are large for mammals of the size of wolverines, and may indicate that wolverines have high energetic requirements and at the same time occupy relatively unproductive niches (Inman et al. 2007a, p. 11). In addition, wolverines naturally occur in low densities that average about one wolverine per 150 km 2 (58 mi 2 ) (Hornocker and Hash 1981, pp. 1292-1295; Hash 1987, p. 578; Copeland 1996, pp. 31-32; Copeland and Yates 2006, p. 27; Inman et al. 2007a, p. 10; Squires et al. 2007, p. 2218).

We received a petition dated August 3, 1994, from the Predator Project (now named the Predator Conservation Alliance) and Biodiversity Legal Foundation to list the North American wolverine in the contiguous United States as an endangered or threatened species under the Act and to designate critical habitat concurrent with listing. On April 19, 1995, we published a finding (60 FR 19567) that the petition did not present substantial information indicating that listing the North American wolverine in the contiguous United States may be warranted. We did not make a determination as to whether the contiguous U.S. population of the North American wolverine constituted a DPS or other listable entity.

On July 14, 2000, we received another petition dated July 11, 2000, submitted by the Biodiversity Legal Foundation, Predator Conservation Alliance, Defenders of Wildlife, Northwest Ecosystem Alliance, Friends of the Clearwater, and Superior Wilderness Action Network, to list the North American wolverine within the contiguous United States as an endangered or threatened species under the Act and to designate critical habitat for the species concurrent with the listing.

On October 21, 2003, we published a 90-day finding that the petition to list the North American wolverine in the contiguous United States did not present substantial scientific and commercial information indicating that listing as threatened or endangered may be warranted (68 FR 60112). We did not determine whether the contiguous U.S. population of the North American wolverine constituted a DPS (or other listable entity), because sufficient information was not available at the time.

On September 29, 2006, as a result of a complaint filed by Defenders of Wildlife and others alleging we used the wrong standards to assess the July 2000 wolverine petition, the U.S. District Court, Montana District, ruled that our 90-day petition finding was in error and ordered us to make a 12-month finding for the wolverine ( Defenders of Wildlife et al. v. Norton and Hogan (9:05cv99 DWM; D. MT)). On April 6, 2007, the Court approved an unopposed motion to extend the deadline for this 12-month finding to February 28, 2008, so that we would be able to use information published in the September 2007 edition of the Journal of Wildlife Management containing a special section on North American wolverine biology. On June 5, 2007, we published a notice initiating a status review for the wolverine (72 FR 31048).

On March 11, 2008, we published a 12-month finding on the wolverine in the contiguous United States (73 FR 12929). In that finding, we determined that the wolverine in the contiguous United States did not constitute a DPS. Therefore, we determined that the wolverine in the contiguous United States was not a listable entity under the Act. On September 30, 2008, Defenders of Wildlife et al. filed a complaint challenging our 12-month finding on the basis of our application of the DPS Policy and the Act. On March 23, 2009, we settled the lawsuit with the plaintiffs and agreed to submit a new 12-month finding to the Federal Register by December 1, 2010.

A complete list of all references is available upon request from the Field Supervisor, Montana Ecological Services Field Office ( See FOR FURTHER INFORMATION CONTACT ).

The primary authors of this document are the staff members of the U.S. Fish and Wildlife Service, Montana Ecological Servies Field Office.

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

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 Federal Lists of Endangered and Threatened Wildlife and Plants that presents substantial scientific or commercial information indicating that listing the species may be warranted, we make a finding within 12 months of the date of the receipt of the petition. In this 12-month finding, we may determine that the petitioned action is: (1) Not warranted, (2) warranted, or (3) warranted, but the immediate proposal of a regulation implementing the petitioned action is precluded by other pending proposals to determine whether species are endangered or threatened, and expeditious progress is being made to add or remove qualified species from the Federal Lists of Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition for which the requested action is found to be warranted but precluded as though resubmitted on the date of such finding, that is, requiring a subsequent finding to be made within 12 months. We must publish these 12-month findings in the Federal Register .

On August 9, 2007, we received a petition, dated August 7, 2007, from the Biodiversity Conservation Alliance and Center for Native Ecosystems requesting that we list the Wyoming pocket gopher ( Thomomys clusius ) within its known historic range, as threatened or endangered under the Act. Additionally, the petition requested that we designate critical habitat concurrent with listing. We acknowledged receipt of the petition in a letter dated September 6, 2007. In that letter, we advised the petitioners that we could not address their petition at that time because responding to existing court orders and settlement agreements for other listing actions required nearly all of our listing funding. We also concluded in that September 6, 2007, letter that emergency listing of the Wyoming pocket gopher was not warranted.

On July 11, 2008, we informed the petitioners that, due to progress on addressing other priority listing actions, funding had become available to allow us to address the petition in fiscal year 2008. On November 4, 2008, the petitioners filed a complaint with the U.S. District Court for the District of Colorado against us for failing to complete the 90-day finding ( Center for Native Ecosystems and Biodiversity Conservation Alliance v. U.S. Fish and Wildlife Service and Kempthorne (1:08-cv-02394-JLK)).

On February 10, 2009, we published our finding that the petition to list the Wyoming pocket gopher presented substantial scientific or commercial information indicating that listing the species may be warranted (74 FR 6558). On March 20, 2009, the petitioners provided a notice of intent to sue on additional grounds for failure to complete the 12-month finding within 12 months of the petition. In a June 12, 2009, stipulated settlement, the Service agreed to complete the 12-month finding by April 10, 2010, which would allow us to include 2009 Wyoming pocket gopher survey data in our analysis. This notice constitutes our 12-month finding on the August 7, 2007, petition to list the Wyoming pocket gopher as endangered or threatened.

Pocket gophers are powerfully built mammals, characterized by a heavily muscled head without a noticeable neck, strong front limbs with long nails used for digging, small ears, small eyes, and fur-lined cheek pouches used to carry food (Verts and Carraway 1999, p. 3). They are highly fossorial (adapted to burrowing or digging), living, foraging, and reproducing in burrow systems and underground tunnels that provide protection from predators and from extreme environmental conditions (Clark and Stromberg 1987, p. 121).

Populations of pocket gophers generally tend to be small and patchily distributed across landscapes where they occur (Kennerly 1959, p. 251; Stinson 2005, p. 21). This distribution is thought to be primarily determined by the availability of soils appropriate for digging and foraging (Kennerly 1959, p. 249; Verts and Carraway 1999, p. 5). Specialization to local ecological conditions has resulted in a high degree of morphological variation across the range of each species (Patton and Brylski 1987, p. 493). For example, pocket gopher coat color is highly variable, strongly correlated with soil color, and thought to be an adaptive response to predation (Ingles 1950, p. 357; Wlasiuk and Nachman 2007, p. 567). Differences in abundance and nutritional content of forage can produce extreme variation in body size of individual pocket gophers and density of pocket gopher populations (Patton and Brylski 1987, p. 504).

Little is known about the Wyoming pocket gopher; assumptions about its distribution, ecology, and status are based on a few museum records, reports from more than 30 years ago, and research conducted in 2008 and 2009. This lack of knowledge has led to the recent efforts to obtain information on its distribution, status, and habitat use (Keinath and Griscom 2008, p. 1; Griscom et al. 2010, p. 3). Where specific life-history information is lacking, and where appropriate, we have provided information from other pocket gopher species, mainly in the Thomomys genus.

The Wyoming pocket gopher is differentiated from other pocket gophers in its geographical range by being smaller and paler, with a yellow cast to the coat, especially in younger animals. The dorsal coat is uniform in color, and the margins of the ears are fringed with whitish hairs (Thaeler and Hinesley 1979, p. 483; Clark and Stromberg 1987, p. 123; Keinath and Beauvais 2006, p. 8; Keinath and Griscom 2008, p. 2). This species does not display sexual dimorphism (differences in form between the sexes) (Clark and Stromberg 1987, p. 123; Keinath and Beauvais 2006, p. 8). Adult Wyoming pocket gophers typically have a body length of 112-134 millimeters (mm) (4.41-5.28 inches (in)), hind foot length of 20-22 mm (0.79-0.87 in), and a weight of 44-72 grams (g) (1.54-2.54 ounces (oz)) (Thaeler and Hinesley 1979, pp. 483-484; Clark and Stromberg 1987, p. 123). The measurements of specimens captured in 2008 and 2009 included body lengths of 86-128 mm (3.38-5.04 in), hind foot lengths of 15-23 mm (0.59-0.91 in), and weights of 43-66 g (1.52-2.33 oz) (Griscom et al. 2010, p. 23). These somewhat smaller measurements for 2008-2009 data can be partly explained by late summer captures that included juveniles, whereas older studies relied on captures prior to June 15 that would have included only adults (Griscom 2010a, pers. comm.).

The Wyoming pocket gopher occurs entirely within the range of the northern pocket gopher ( Thomomys talpoides ), but the two species likely occupy different habitats locally (Thaeler and Hinesley 1979, p. 486; Keinath and Beauvais 2006, p. 8; Griscom et al. 2010, p. 15). Approximately 50 percent of the known range of the species occurs on Bureau of Land Management (BLM) lands (Service 2009a, p. 1). A Wyoming Natural Diversity Database (WYNDD) predictive distribution model for the Wyoming pocket gopher developed in January 2010 shows the species could occur in Sweetwater, Carbon, and Fremont Counties in Wyoming (Griscom et al. 2010, p. 32). The predicted range abuts Colorado's northern border, but Colorado was not included in the distribution analysis (Griscom et al. 2010, p. 32). Additional specimens are considered unlikely to be found south of current distribution points (Griscom et al. 2010, p. 12). To date, Wyoming pocket gophers have been located only in Sweetwater and Carbon Counties, which is consistent with historical records that show this area to be the extent of the species' range. Although the full historic range of the species has not been defined, we consider the capture points in Sweetwater and Carbon Counties presented by Thaeler and Hinesley (1979, pp. 482, 486-487) to present an approximation of historic range. This historic range includes the type specimen collected in 1857, two specimens collected in 1949 and 1951, and several specimens collected in the 1960s and 1970s (Thaeler and Hinesley 1979, p. 487). Very little information exists regarding the actual population size of the Wyoming pocket gopher (Keinath and Beauvais 2006, p. 21). The only population estimate we found was 10,000 (NatureServe 2009, unpaginated). However, we are unable to determine the basis for this estimate and thus have no way to determine its scientific validity.

Vegetation composition of a site may be more important in determining habitat for the Wyoming pocket gopher than soils or topography (Keinath and Griscom 2008, p. 2). The Wyoming pocket gopher occurs primarily in small “islands” of low vegetation within a sagebrush matrix. This matrix typically includes Artemesia tridentada wyomingensis (Wyoming big sagebrush), Chrysothamnus spp. (rabbitbrush), and other low shrubs, cushion plants, grasses, and forbs (Keinath and Griscom 2009, p. 1). In comparison to unoccupied control sites and northern pocket gopher capture sites, the Wyoming pocket gopher appears to prefer areas within this matrix with less perennial grass cover, less Artemesia tridentata (Big sagebrush), more Krascheninnikovia lanata (winterfat), more Atriplex gardneri (Gardner saltbush), more bare soil, less litter, and fewer surface rocks (Griscom et al. 2010, p. 15). Difference in habitat use would be expected, given that phenotype (observable physical characteristics) has been shown to correlate with habitat for pocket gophers (Ingles 1950, p. 357; Wlasiuk and Nachman 2007, p. 567).

Previously, the Wyoming pocket gopher was believed to exclusively occupy well-drained, gravelly ridges instead of the valley bottoms and riparian areas with deeper soils preferred by the northern pocket gopher (Thaeler and Hinesley 1979, p. 486). However, recent research showed Wyoming pocket gophers occupy sites with more varied topography (Keinath and Griscom 2008, p. 2). Compared to northern pocket gophers, Wyoming pocket gophers appear to prefer areas of lesser slopes (Griscom et al. 2010, p. 15). Wyoming pocket gophers appear to use a variety of soil types that can be more compacted than those used by northern pocket gophers (Griscom et al. 2010, p. 15). These soils often have a substantial gravel component, usually contain little clay (Keinath and Griscom 2008, p. 2), and tend to be more alkaline than the soils that northern pocket gophers prefer (Griscom 2009a, pers. comm.). In general, pocket gophers in the Thomomys genus are more specialized for tooth digging rather than claw digging, which allows for exploitation of a broader range of soil types (Lessa and Thaeler 1989, p. 696). Based on the characterization of the Wyoming pocket gopher's size and habitat, it appears to fit the island model of isolation displayed by other species of pocket gophers specifically adapted to the soils of an area (Miller 1964, pp. 259-260). The limited distribution of the Wyoming pocket gopher relative to other species of pocket gopher may be due to its specialized habitat requirements (Keinath and Beauvais 2006, pp. 12-15).

Pocket gophers construct extensive burrow systems. These systems consist of a main tunnel with side branches of shallow feeding tunnels (tunnels dug to forage on plant material). Additional feeding tunnels can be constructed when plant production is poor (Davis 1938, p. 338; Reichman et al. 1982, p. 691). The main tunnel also connects to a smaller system of chambers that serve as nest sites, food caches, and latrines (Miller 1964, p. 257; Keinath and Beauvais 2006, p. 16). Depths of the burrows vary from 6 to 12 inches below the ground surface. All aboveground entrances are plugged with soil (Clark and Stromberg 1987, p. 121). Burrow widths of the Wyoming pocket gopher are significantly smaller than those of the northern pocket gopher, likely reflecting their smaller body size (Griscom et al. 2010, p. 15). The extent of burrow systems can vary with the size of the individual, soil type, and plant production. The extensive tunneling and feeding activity of pocket gophers can have strong effects on soil formation, hydrology, nutrient flows, plant diversity, and competitive interactions of plants (Tilman 1983, pp. 290-292; Huntly and Inouye 1988, entire; Reichman and Seabloom 2002, entire; Sherrod et al. 2005, pp. 586-587; Kyle et al. 2008, p. 377). The effects of pocket gopher burrowing on physical and chemical soil properties vary based on the nature of the soil (Kerley et al. 2004, pp. 164-165).

The diet of pocket gophers consists of roots, stems, and leaves of forbs, with some consumption of grasses and shrubs (Aldous 1951, pp. 85-86; Ward and Keith 1962, p. 747). The average consumption of forbs by pocket gophers in west-central Colorado, as measured by stomach content, was highest in July and August at 96 percent, decreasing to 73 percent in October (Ward and Keith 1962, p. 747). Consumption of shrubs and roots of all types increased in late September and October, and consumption of grasses increased in June, September, and October (Ward and Keith 1962, p. 747). Pocket gophers in the Thomomys genus throughout the western United States generally prefer forb shoots during the growing season, and grass shoots, corms, and roots during periods of plant dormancy (Hunt 1992, pp. 47-48). Other species of the Thomomys genus (e.g., northern pocket gopher, Botta's (valley) pocket gopher ( T. bottae ), Townsend's pocket gopher ( T. townsendii ), Mazama (western) pocket gopher ( T. mazama ), and Camas pocket gopher ( T. bulbivorus )) are not strict herbivores, in that they also seasonally consume the fungi associated with plant roots (i.e., are mycophagous) (Maser et al. 1978, p. 805; Taylor et al. 2009, p. 367). Pocket gophers may cut their food into small pieces and carry it in their cheek pouches back to the main burrow where it is consumed, stored for winter, used for nest building, or taken into tunnels and later pushed to the surface (Aldous 1951, p. 84; Verts and Carraway 1999, p. 6). Pocket gophers remain active all winter (Clark and Stromberg 1987, p. 121).

Based on the life histories of other pocket gophers, Wyoming pocket gophers presumably reproduce the calendar year following birth, have one litter with 4 to 6 young per year, and usually do not live more than two breeding seasons (Keinath and Beauvais 2006, p. 18). However, one northern pocket gopher is known to have survived for about 4 years (Hansen 1962, p. 153). Some species of pocket gophers have more than one litter per year in southern climates with longer breeding seasons (Miller 1946, pp. 335-336). Hansen (1960, p. 332) found no evidence of more than one annual litter per female in the Rocky Mountain region.

Pocket gophers are solitary animals and are typically found together only during the breeding season, or when females have young. Variation in levels of tolerance between males and females ranges from being together only during mating to raising young of the year together (Hansen and Miller 1959, pp. 581-582). Pocket gophers are usually polygynous (Reichman et al. 1982, p. 693). However, some evidence of serial monogamy has been found in Botta's pocket gopher in Arizona (Reichman et al. 1982, p. 693). The sex ratio for Botta's pocket gopher was one male per one female; however, the effective sex ratio was one male per two females as some small males did not reproduce (Reichman et al. 1982, p. 693). Populations of Botta's pocket gopher in California showed a much more skewed sex ratio, ranging from 1.4 to 4.67 females per male (Patton and Feder 1981, p. 917). We do not have specific information regarding the Wyoming pocket gopher mating system or sex ratio.

Outside of the breeding season, pocket gophers are highly territorial, and males and females have exclusive territories. Generally, pocket gophers avoid each other (Reichman et al. 1982, p. 693). The infrequent interactions that occur are mostly agonistic, occasionally escalating to open combat and even death (Zinnel and Tester 1994, p. 96). This aggression appears to have evolved as a means to ensure adequate individual food supplies, but could also be related to reproductive behaviors like mate guarding (Zinnel and Tester 1994, pp. 99-100). Pocket gopher population density is likely to be primarily regulated through intraspecific aggression; the number of animals an area can hold appears to be determined by combative interactions (Zinnel and Tester 1994, p. 100).

Dispersal strategies of the Wyoming pocket gopher are unknown, but may be similar to other pocket gopher species. Although dispersal was common, 63 percent of individual Botta's pocket gophers set up their territory within 40 meters (m) (131.23 feet (ft)) of their natal home (Daly and Patton 1990, p. 1291). Average dispersal lengths for Botta's pocket gopher are estimated at 100-500 m (328.08-1,640.42 ft) per year (Hafner et al. 1998, p. 281). Individual Botta's pocket gophers that disperse are typically young, pre-reproductive, and more likely to be female (Daly and Patton 1990, p. 1287). Pre-reproductive juvenile females begin dispersing as early as the summer following their birth, while males typically delay dispersal for up to one year after birth (Daly and Patton 1990, p. 1287). Spring dispersal is common in reproductive adults of both sexes. Fifty percent of plains pocket gopher ( Geomys bursarius ) female adults relocate after raising a litter, leaving the site in possession of female young (Zinnel and Tester 1994, p. 99). Once pocket gophers establish territories and burrows, they may shift to other areas based on environmental conditions or interactions with other pocket gophers, but they generally do not move far from original territories (Miller 1964, p. 262; Reichman et al. 1982, pp. 687-688; Daly and Patton 1990, p. 1286).

The Wyoming pocket gopher ( Thomomys clusius ) is a member of the Geomyidae (pocket gopher) family. Including the Wyoming pocket gopher, nine species are currently assigned to the genus Thomomys . The type specimen for Wyoming pocket gopher was collected in 1857 by Dr. W.A. Hammond near Rawlins, Wyoming, but was not described and given the name Thomomys clusius until 18 years later (Coues 1875, p. 138). The designation of the Wyoming pocket gopher within Thomomys has changed over time, with the name clusius being applied at both the species and subspecies level to various pocket gopher specimens collected in southern Wyoming (Keinath and Beauvais 2006, p. 11).

Thaeler and Hinesley (1979, entire) clarified the Wyoming pocket gopher taxonomy with karyotype (i.e., a count of the number of diploid chromosomes) and morphological analyses of pocket gopher specimens collected in Wyoming. Members of the pocket gopher genus Thomomys are the most karyotypically and morphologically diverse group of mammals known (Patton 1972, p. 574; Patton and Brylski 1987, p. 493). The Wyoming pocket gopher has a unique karyotype of 2n = 46, a yellowish coat, and a generally small size, which support the validity of Wyoming pocket gopher as a distinct species within Thomomys (Thaeler and Hinseley 1979, p. 483). These traits differed significantly from the northern pocket gopher, which occurs across the range of the Wyoming pocket gopher. Although northern pocket gophers are generally darker and larger, they share morphological similarities with Wyoming pocket gophers that had led to some misidentification of specimens in earlier publications (e.g., Bailey 1915 and Long 1965, cited in Keinath and Beauvais 2006, p. 11). Thus, karyotype analysis was previously thought necessary for positive identification. Northern pocket gophers differ from Wyoming pocket gophers in that they have a karyotype of 2n = 48 or 56, depending on the subspecies (Thaeler and Hinesley 1979, p. 483). However, based on the amplified fragment length polymorphism (AFLP) analysis completed on tail clippings during the 2008 field season, field assessment of phenotype was shown to be a reasonably reliable method for discerning the two species from each other (Hayden-Wing Associates 2008, p. 3; Beauvais 2009, p. 1; McDonald 2009a, pers. comm.). AFLP testing showed strong genetic signals that clearly differentiate the Wyoming pocket gopher from other species of pocket gophers (Beauvais 2009, p. 1; McDonald 2009a, pers. comm.). This recent genetic analysis has confirmed definitively what taxonomists had determined historically: the Wyoming pocket gopher is a unique species representing a monophyletic clade (i.e., descended from one common ancestor) (McDonald 2009a, pers. comm.).

Section 4 of the Act, and its implementing regulations at 50 CFR 424, set forth the procedures for adding species to, removing species from, or reclassifying species on the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, a species may be determined to be endangered or threatened based on any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. Under section 4(b)(1)(A), this determination should be made on the basis of the best scientific and commercial data available and after conducting a status review and taking into consideration State conservation efforts. In making our 12-month finding on a petition to list the Wyoming pocket gopher, we considered and evaluated the best available scientific and commercial information. Information pertaining to the status and threats to the Wyoming pocket gopher in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Wyoming pocket gopher habitat is exposed to a number of influences that may affect the species, including energy exploration and development, road construction and use, climate change and drought, introduction of nonnative species, grazing, and urbanization. However, no studies have been conducted to determine the species' response to these influences, or to the potential changes in habitat that may result. Where information specific to the Wyoming pocket gopher is lacking, we have utilized information from other pocket gopher species, mainly in the Thomomys genus.

Literature describes both positive and negative effects to other species of pocket gophers resulting from various types of disturbance. Many pocket gopher species exhibit a positive response of increased rates of mound-building activities when vegetation has been disturbed (Mielke 1977, p. 175). Three species (Botta's pocket gopher, plains pocket gopher, and yellow-faced pocket gopher ( Cratogeomys castanops )) are more common in disturbed areas, such as roadways and floodplains, in New Mexico (Best 1973, p. 1314). Similarly, pocket gopher ( Thomomys spp.) burrows were frequently observed along roadways in Nevada, but not the adjacent creosote habitats, suggesting they were using areas where the habitat would have been unsuitable without the disturbance (Garland and Bradley 1984, p. 54). In contrast, plains pocket gophers and yellow-faced pocket gophers in southwestern Kansas are not present within areas of intensive agricultural operations involving annual plowing or disking (Hoffman et al. 2007, p. 300). Intensive residential and commercial development has reduced patch sizes of Mazama pocket gopher habitat in western Washington such that the species no longer occurs in many areas (Service 2009b, pp. 7-8; Flotlin 2010, pers. comm.). The response to disturbance may be dependent on the species, as the plains pocket gopher is more common in disturbed areas, such as roadsides and cultivated fields, while the yellow-faced pocket gopher is more common in native shortgrass prairie in southeastern Colorado (Moulton et al. 1983, p. 58).

In 2008 and 2009, WYNDD, with the assistance of several other groups, trapped Wyoming pocket gophers, northern pocket gophers, and Idaho pocket gophers ( T. idahoensis ) to better understand the species' range and distribution, habitat requirements and preferences, and the genetic and morphological differences between species (WYNDD 2009, p. 2; Hayden-Wing Associates 2008, p. 1; Keinath and Griscom 2008, p. 1; Griscom et al. 2010, pp. 5-7). This effort resulted in the successful trapping of 31 confirmed Wyoming pocket gophers distributed across the species' currently known range (Griscom et al. 2010, p. 5; Griscom 2010b, pers. comm.). Prior to 2008, a total of 16 confirmed Wyoming pocket gophers had been captured, and all of these confirmed specimens were collected by Charles Thaeler approximately 40 years ago (Griscom 2009b, pers. comm). This information provided both historic and recent locations for our use in creating a general assessment of Wyoming pocket gopher presence to ascertain if the known locations of the species have changed over time. Based on the limited number of collection sites, the species appears to be currently distributed throughout its known range in a pattern that approximates historic distribution (Figure 1). Therefore, we find no evidence that curtailment of the species' range is occurring.

Figure 1: Historic and current capture locations of the Wyoming pocket gopher (Data compiled from Service, Bureau of Land Management, WYNDD, U.S. Geological Survey, U.S. Census Bureau, ESRI).

Although there is no evidence of curtailment of the species' range, habitat of the Wyoming pocket gopher is exposed to various influences that may affect the species, including energy exploration and development, road construction and use, introduction of nonnative species, climate change, drought, grazing, and urbanization. These variables that may affect the species' habitat are discussed below.

The primary forms of existing and planned energy development in the range of the Wyoming pocket gopher are oil, gas, and wind. Based on existing National Environmental Policy Act (NEPA) (42 U.S.C. 4321 et seq. ) documents for major oil and gas developments, estimates of project life for major oil and gas developments within the Wyoming pocket gopher's range are between 10-50 years (Service 2010a, p. 3). Some non-renewable energy development is already occurring within the species' known occupied range. Renewable energy development is estimated to reach maximum development by 2030 (U.S. Department of Energy 2008, p. 10), and several developments are being considered within the species' range. Based on this information, we estimate the foreseeable future of energy development at a minimum of 10 years, but anticipate that energy development will be present for up to 50 years.

WYNDD is analyzing potential threats to Wyoming's 152 species of greatest conservation need related to energy development in its Assessment of Wildlife Vulnerability to Energy Development (AWVED). Preliminary conclusions from the AWVED analysis indicate that the Wyoming pocket gopher is Wyoming's species with the highest potential risk for energy-related effects based on its proximity to existing wells, the proportion of lands leased for oil and gas within its range, and the density of wells within that range (Keinath 2009, pp. 12-13). This potential risk is based on exposure to energy development across the species' range and is not based on any known effects to the species from energy development activities. Our February 10, 2009, 90-day finding (74 FR 6558) acknowledged that the likelihood of oil and gas development throughout the species' range is high based on the energy development potential and existing leases that cover much of the range. Approximately 4,000 actively producing oil and gas wells are within the range of the species (Service 2010b, p. 3), and an additional 10,000 oil and gas wells have been proposed in that area (Service 2010a, p. 1). In this finding, rather than what was done in our previous 90-day finding on the petition, we are determining whether the best available information indicates that the species meets the definition of a threatened or endangered species and therefore warrants listing under the Act, which is a more in-depth analysis than the one conducted for the 90-day finding.

Several different types of oil and gas exploration and development activities occur within the range of the Wyoming pocket gopher. Oil and gas geophysical exploration is conducted to generate a subsurface image of fluid minerals and usually involves either drilling holes and detonating explosives or using a vibrating pad that is driven across an area using heavy vehicles. The extent of impacts from either exploration method on pocket gophers is unknown. The vibrations and potential soil impacts would, at a minimum, temporarily alter habitat and may result in collapse of burrows. Pocket gophers in the immediate vicinity of operations would likely notice the activity, but the type of response is unknown. Pocket gopher communication likely occurs through seismic signals (Mason and Narins 2001, p. 1177), and frequent vibrations could disrupt signals used to attract mates, warn of intruders, or avoid predators. However, we have no information to support that energy exploration negatively impacts the species.

Oil and gas development involves staging a drilling rig and setting up additional equipment that is used during production. Generally, developers build roads to access each site and clear and level well pads. These soil-disturbing activities would affect the habitat that lies within and adjacent to the footprint of well pads and roads. Any soil that is moved could have a direct impact on pocket gophers that are present. Once a rig is in place, the drilling process creates vibrations that could affect habitat and any pocket gophers in the area. Once a well has been drilled and is producing, energy companies make regular trips to well pads to monitor production, conduct maintenance, or collect extracted resources. These regular trips may disturb, either directly or through the resulting noise, pocket gophers that are present at or near well pads and roads. In the past, the Wyoming pocket gopher has been considered potentially vulnerable to disturbance because the reasons for the species' limited distribution had not yet been explained (Keinath and Beauvais 2006, p. 21). However, as described above, certain types of disturbance can elicit a positive population response in some pocket gopher species.

Energy producers often try to maintain a clear work area by using herbicides on well pads and along roads. Herbicide use and the direct impacts of development would reduce the availability and quality of vegetation, creating negative effects to Wyoming pocket gopher habitat (Keith et al . 1959, pp. 142-144). In general, broadcast herbicide application is assumed to be minimal in southern Wyoming (Keinath and Beauvais 2006, p. 22). We do not have information on use of herbicides for oil and gas development, and we are unaware of monitoring for resulting vegetative shifts. Therefore, we are unable to assess how changes in the vegetation due to herbicide use may affect the Wyoming pocket gopher. The BLM does not use pesticides or rodenticides in Wyoming to protect reclamation areas (Abbott 2009a, pers. comm.), so we do not anticipate direct mortality from these substances in reclamation areas. Introduction and spread of nonnative plants may result from energy development activities, and the potential threat of nonnative vegetation to the Wyoming pocket gopher is discussed separately below.

We used information from Wyoming pocket gopher trapping and from known oil and gas development to assess the extent to which energy development may be affecting the species. By overlaying producing wells on a map with species capture sites, we found that the locations of capture sites in relation to new and existing development does not appear to reflect a pattern of either species avoidance of, or preference for, producing oil and gas wells. Some capture sites are as near as 95 m (312 ft) to a producing well site (Service 2010b, p. 2), while others are in areas that have no oil or gas wells. We recognize that this simple geospatial assessment has limitations in determining what effects oil and gas development has on the species. We also recognize dispersal is likely already difficult across portions of the range that do not currently have pocket gophers, and recolonization following local extirpation would be unlikely (Keinath et al . 2008, p. 7).

The amount of surface disturbance provides another approach to consider the impacts of natural gas development. The two largest natural gas developments not yet fully built in the Wyoming pocket gopher range are Atlantic Rim and Continental Divide-Creston (Service 2010a, p. 1). The scoping notice for the Continental-Divide Creston development states disturbances during initial development will be approximately 47,060 acres (ac) (19,045 hectares (ha)) of 1.1 million ac (445,154 ha), or 4.28 percent of the project area (BLM 2006a, p. 4). The impacted area will be reduced to 1.67 percent through interim reclamation (BLM 2006a, p. 4). As this proposal includes areas of infill, the amount of disturbance described in the scoping notice does not include existing development (BLM 2006a, p. 1). The proposed well density includes 8 wells per square mile, with a possibility of up to 16 wells per square mile in certain areas (BLM 2006a, p. 1). The Record of Decision for the Atlantic Rim development allows a total surface disturbance of 2.8 percent of the project area at a given time, with well spacing of 8 wells per square mile (BLM 2007, p. 10). For comparison, the existing Continental Divide/Wamsutter II gas development has been mostly developed, with 22,400 ac (9,065 ha) of surface disturbance across 1,061,200 ac (429,452 ha) (2.11 percent of the project area) and well densities of 1 to 8 wells per square mile (BLM 2000, section 2.0). All of these surface disturbance percentages are small. Although we do not know how the Wyoming pocket gopher is likely to respond to any proposed increases in well numbers, the level of development indicates that large interstitial spaces will continue to be available for Wyoming pocket gopher use. We know from our analysis that the Wyoming pocket gopher does occur near developed areas (Service 2010b, p. 2).

The BLM administers approximately half of the lands within the Wyoming pocket gopher range (Service 2009a, p. 1). Throughout the range, the BLM has leased 41.23 percent of the Wyoming pocket gopher range for oil and gas development, and 11.23 percent of the range on BLM lands has producing oil and gas leases (Service 2010c, p. 2). We are unable to determine whether development will occur on all leases.

Given limited knowledge of pocket gopher response to oil and gas development, and both the positive and negative observed impacts of disturbance to other species of pocket gophers, we do not consider producing wells at current or projected levels to be a threat to the Wyoming pocket gopher.

Although little wind development has occurred within the range of the species, projections for future wind energy are significant. One major proposal, the Chokecherry and Sierra Madre Wind Energy Project, includes 1,000 wind turbines across 98,500 ac (39.66 ha) within the range of the Wyoming pocket gopher (AECOM 2009, p. 1). Wind development may cause effects to habitat that are similar to oil and gas development. Wind development also results in a network of pads connected by roads. Soils are disturbed during development, and frequent maintenance trips are necessary. The Wyoming pocket gopher's response to wind development within its habitat is not known. For the Botta's pocket gopher, researchers mapping prey base to better understand raptor mortalities at a wind farm in California observed that pocket gophers were clustered near the wind turbines (Thelander et al . 2003, p. 23). They attributed this to the pocket gophers' attraction to the vertical and lateral edges formed by access roads and the area around wind towers (Thelander et al . 2003, p. 24). We anticipate that the response of the Wyoming pocket gopher may be similar, but we lack species-specific information. Therefore, the best available information does not indicate whether current or future wind development will have positive or negative effects on the Wyoming pocket gopher.

Little information exists to indicate whether the Wyoming pocket gopher will be affected by an increased density of wells or by an expansion of oil, gas, and wind development into currently undeveloped areas. The response to disturbance in pocket gophers appears to be species-specific. For example, in southeastern Colorado, the plains pocket gopher is more common in disturbed areas, but the yellow-faced pocket gopher is more common in native versus disturbed habitats (Moulton et al . 1983, p. 58). Based on our current understanding of the Wyoming pocket gopher, energy development, at levels that we can detect or anticipate, is as likely to benefit Wyoming pocket gophers as it is to harm them.

We have no information that additional energy development activity will fragment habitat in a way that will significantly limit dispersal, movement, or genetic interchange. Using the best available information, we conclude that these habitat alterations do not constitute a threat to the Wyoming pocket gopher now, or in the foreseeable future.

Roads are built to create access for oil, gas, and wind developments, as well as for other activities that occur on the landscape, including recreation, grazing, and land management. Much of the recent expansion of road networks in Wyoming pocket gopher habitat is related to energy development, but some areas have also likely experienced an increase in access by recreational vehicles. Expansion of road networks may fragment the species' habitat, create barriers to movement of the species, isolate individual populations, and increase opportunities for invasive species (Keinath and Beauvais 2006, pp. 22-23). Roads may increase direct mortality from vehicles, but this source of mortality is not always significant to populations (Garland and Bradley 1984, p. 52). Roads also may improve habitat for pocket gophers in some ways by providing looser soil and increasing vegetation in rights-of-way from precipitation run-off. As described above, roads can have a positive effect on other pocket gopher species (Best 1973, p. 1314; Moulton et al . 1983, p. 58; Garland and Bradley 1984, p. 54). The effects of roads on Wyoming pocket gopher populations are not known; however, we have limited anecdotal observations of individual gopher occupancy near roads. In 2009, one Wyoming pocket gopher specimen was captured 7 m (23 ft) from a graded dirt road, and northern pocket gophers were captured as close as 2 m (6.5 ft) to a graded dirt road (Griscom 2009b, pers. comm.). Small mammals may avoid roads due to noise and other factors, but roads may also provide additional habitat or movement corridors (Garland and Bradley 1984, entire; U.S. Department of Transportation 2009, unpaginated). Northern pocket gophers have been observed digging tunnels underneath a right-of-way road (Richens 1966, p. 532).

Depending upon the size of the road and the associated degree of soil compaction, a road may impact the dispersal of Wyoming pocket gophers. For example, distribution of the Shelton pocket gopher ( T. mazama couchi ) was impacted by soil compaction around an airport runway, and no pocket gopher activity was observed in graded areas that appeared to be highly compacted (GeoEngineers 2003, p. 15). The Wyoming pocket gopher apparently can use more compacted soils than the northern pocket gopher (Griscom et al . 2010, p. 15), but we are unsure what amount of soil compaction would begin to limit habitat use by the Wyoming pocket gopher.

Many roads in the range of the Wyoming pocket gopher have been on the landscape for decades or for more than a century, while others have been developed within the past few years. Evidence suggests some historic wagon trails (a type of road) have lasted for well over 100 years (BLM 2009, unpaginated), even when use of the road is discontinued. Other roads are reclaimed and do not have such a lasting effect. We anticipate that the existing roads within the range of the Wyoming pocket gopher will persist for at least 10 to 50 years in support of energy development activities. Additional roads may also be constructed to support that development, while others are reclaimed when no longer necessary. We anticipate that county roads providing access to livestock management facilities, homes, and recreational opportunities will persist indefinitely.

We conclude the effects of roads on the Wyoming pocket gopher may be positive and negative. Although we remain concerned about the potential impacts of roads, the best available information does not indicate that road construction and use poses a threat to the Wyoming pocket gopher now, or in the foreseeable future.

The introduction of nonnative species may affect the Wyoming pocket gopher, but the degree of impact from these species is not clear. A review of Wyoming pocket gopher information resulted in no information indicating a likelihood that nonnative vegetation alters or restricts pocket gopher populations; nonnative species were viewed as a potential threat, but not a current threat (Keinath and Beauvais 2006, p. 23). We do not fully understand the extent to which nonnative species will spread throughout the species' range into the future. Nonnative vegetation is considered a threat to the Mazama pocket gopher in western Washington (Service 2009b, pp. 7-8). The Mazama pocket gopher is adapting to the presence of many types of nonnative vegetation; however, the presence of Cytisus scoparius (Scotch broom), which has large root masses, restricts pocket gopher dispersal. The loss of prairie habitat to conifer encroachment is also a threat to the Mazama pocket gopher (Flotlin 2010, pers. comm.). Cytisus scoparius does not occur within the range of the Wyoming pocket gopher, and conifer encroachment is limited.

To inform our evaluation of the potential threat from nonnative species, we looked at the potential for Bromus tectorum (cheatgrass) to impact Wyoming pocket gopher populations. The conversion from A. tridentata spp. to B. tectorum has been shown to negatively impact other small mammals (Yensen et al . 1992, p. 309). The spread of B. tectorum has the potential to change vegetative communities in a way that could affect the Wyoming pocket gopher. As discussed previously, forbs are an important component of pocket gopher diets, and high densities of B. tectorum reduce the biomass and growth rates of forbs, as well as seedling survival for some forb species (Parkinson 2008, pp. 37-46). Further, when chemical treatments were used to experimentally reduce the abundance of weedy forbs in favor of grasses, a northern pocket gopher population declined roughly in proportion to the loss of forbs (Keith et al . 1959, p. 231).

Pocket gophers that eat grass species have reduced body weights (Tietjen et al . 1967, pp. 642-643). Grasses, when not consumed with other vegetation, do not seem to provide an adequate diet for Thomomys species (Cox 1989, p. 80). While Bromus tectorum may impact the abundance of forbs in the species' habitat, B. tectorum may also be used by Wyoming pocket gophers. Small quantities of the seeds of B. tectorum have been occasionally found in tunnels of northern pocket gophers, although seed heads of B. tectorum were not preferred as forage (Cox 1989, pp. 78-80). Northern pocket gophers also occur at locations where B. tectorum was considered to be a prevalent plant species (Ostrow et al . 2002, p. 992). During their breeding season, Botta's pocket gophers have been found to consume substantial quantities of species related to B. tectorum, B. mollis (soft brome) and B. rubens (red brome), when the nutrient content of the plants was highest (Hunt 1992, p. 49).

While Bromus tectorum appears to have the potential to impact Wyoming pocket gopher habitat, the spread of B. tectorum throughout the habitat of the Wyoming pocket gopher is not a foregone conclusion. In Wyoming, B. tectorum can be locally abundant, but precipitation and elevation differences influence where B. tectorum occurs (Smith and Enloe 2006, p. 1). In southern Wyoming counties, the fall precipitation prior to cold weather needed for B. tectorum germination is generally rare in zones where 14 inches or less of precipitation is received annually (Smith and Enloe 2006, p. 1). The annual precipitation within the range of the Wyoming pocket gopher is generally less than 14 inches of precipitation annually (National Atlas 2005, unpaginated).

In approximately the last 100 years, no broad-scale B. tectorum eradication method has been developed. Given the history of invasive plants on the landscape, the continued challenges in controlling such species, and the current infestation of invasive plants across the Wyoming pocket gopher's range, we anticipate that invasive plants will be on the landscape for the next 100 years or longer. However, studies indicate B. tectorum germination may be generally rare in Wyoming pocket gopher habitat, possibly inhibiting the future spread and impact of this invasive species in Wyoming pocket gopher habitat. In summary, we could find no information suggesting that nonnative species or B. tectorum , where it occurs within the occupied range of the Wyoming pocket gopher, represent a threat to the species now, or in the foreseeable future.

The Intergovernmental Panel on Climate Change (IPCC) has concluded that warming of the climate is unequivocal and that continued greenhouse gas emissions at or above current rates will cause further warming (IPCC 2007, p. 30). Eleven of the 12 years from 1995 through 2006 rank among the 12 warmest years in the instrumental record of global surface temperature since 1850 (Independent Scientific Advisory Board 2007, p. 6). Climate-change scenarios estimate that the mean air temperature could increase by more than 3 degrees Celsius (5.4 degrees Fahrenheit) by 2100 (IPCC 2007, p. 46). The IPCC also projects that there will very likely be regional increases in the frequency of hot extremes, heat waves, and heavy precipitation (IPCC 2007, p. 46), as well as increases in atmospheric carbon dioxide (IPCC 2007, p. 36).

Plant species provide habitat and forage that affect the ability of mammal species, such as the Wyoming pocket gopher, to persist over time. A variety of plant-related factors are not included in climate space models, including the effect of elevated carbon dioxide on plant water-use efficiency, the physiological effect to the species of exceeding the assumed (modeled) bioclimatic limit, the life stage at which the limit affects the species (seedling versus adult), the life span of the species, and the movement of other organisms into the species' range (Shafer et al . 2001, p. 207). These factors would likely help determine how climate change would affect plant species distributions. While more empirical studies are needed on what determines species and multi-species distributions, those data are often lacking; in their absence, climatic space models can play an important role in characterizing the types of changes that may occur so that the potential impacts on natural systems can be assessed (Shafer et al . 2001, p. 213).

One study modeled potential climate change impacts to A. tridentata spp., which are representative of the ecosystem currently known to be occupied Wyoming pocket gopher habitat (Shafer et al . 2001, pp. 200-215). Each scenario in the study predicted a reduction in the size of the overall range of sagebrush and shift where sagebrush may occur. These simulated changes were the result of increases in the mean temperature of the coldest month, which the authors speculated may interact with soil moisture levels to produce the simulated impact. Each model predicted that climate suitability for big sagebrush would shift north into Canada. Other areas within big sagebrush distributions would become less suitable climatically and would potentially cause a significant contraction in sagebrush range. Since the Wyoming pocket gopher is associated with sagebrush in the matrix that forms Wyoming pocket gopher habitat, contractions of sagebrush could result in negative effects to the species. However, although the Wyoming pocket gopher occurs within sagebrush habitats, the species prefers vegetation other than sagebrush at a finer scale within that matrix (Griscom et al . 2010, p. 15).

In some cases, effects of climate change can be demonstrated (e.g., McLaughlin et al . 2002, p. 6073). Where it can be, we rely on that empirical evidence, such as increased stream temperatures (see Rio Grande cutthroat trout, 73 FR 27900, May 14, 2008) or loss of sea ice (see polar bear, 73 FR 28212, May 15, 2008), and treat it as a threat that can be analyzed. The degree to which climate change will interact with ecological processes important to Wyoming pocket gophers is not currently known.

Based on the evolutionary and ecological response of pocket gopher species to past global warming and cooling events, changes in temperature and precipitation may result in phenotypic and density changes in Wyoming pocket gopher populations (Hadly 1997, p. 292; Hadly et al . 1998, p. 6896; Barnosky et al . 2003, pp. 360-361), but we have no information specific to the Wyoming pocket gopher. If the Wyoming pocket gopher's range experiences increased temperatures and reduced precipitation in the future, these changes could include reduced body size and population abundance (Hadly 1997, p. 292). Past climate-induced, population-level, phenotypic change in pocket gophers was likely the result primarily of developmental plasticity within populations and not large-scale migration (Hadly et al . 1998, p. 6896; Barnosky et al . 2003, p. 362). Measured changes in phenotype and population size appeared to be an initial response to global warming episodes, with the extent of change being dependent upon the magnitude and duration of climatic change (Barnosky et al . 2003, pp. 364-365).

Smaller body size and reduced abundance experienced by historical pocket gopher populations during global hot, dry periods is likely a response to reduced food availability during those periods (Hadly 1997, p. 290). Projected climate change has the potential to significantly alter the distribution of forage important to pocket gophers through shifts in timing and amount of precipitation, or through changes in seasonal high, low, or average temperatures (Bachelet et al . 2001, p. 174). For example, warmer temperatures and greater concentrations of atmospheric carbon dioxide create conditions favorable to Bromus tectorum , which outcompetes native vegetation and greatly accelerates the natural fire cycle in areas where it becomes established (Chambers and Pellant 2008, p. 31; Global Climate Change Impacts in the United States 2009, p. 83). Future carbon dioxide emissions from energy use are projected to increase by 40 to 110 percent between 2000 and 2030 (IPCC 2007, p. 44). If a resulting shift in the vegetative communities occurs within the range of the Wyoming pocket gopher, the displacement of native forbs and grasses could significantly alter the availability of sufficient forage resources. This could then be exacerbated by the continued loss of those resources as a result of the shortened fire cycle.

Application of continental-scale climate change models to regional landscapes and even more local or “step-down” models projecting habitat potential based on climatic factors is informative, but contains a high level of uncertainty when predicting future effects to the Wyoming pocket gopher and its habitat due to a variety of factors, including regional weather patterns, local physiographic conditions, life stages of individual species, generation time of species, and species' reactions to changing carbon dioxide levels. The models summarized above are limited by these types of factors; therefore, their usefulness in assessing the threat of climate change on the Wyoming pocket gopher into the future is also limited.

Drought conditions occur within the range of the Wyoming pocket gopher and are a natural process that has historically occurred separately from climate change. We anticipate natural drought cycles to occur periodically within the range of the Wyoming pocket gopher into the future. We could find no specific information regarding the effects of drought on the Wyoming pocket gopher. Presumably drought would likely affect forage growth and potentially limit food availability. While this may have temporary effects on population numbers and the reproductive ability of the Wyoming pocket gopher, the species continues to occupy its known range despite historic periods of natural drought.

The direct, long-term impact from climate change to the Wyoming pocket gopher is not known. Shifts in the vegetative community may affect the species' ability to forage. However, given our lack of knowledge of important food resources for the Wyoming pocket gopher, our resulting lack of understanding about how changes in the forage base may affect the species, and our uncertainty regarding the effects of climate change on those food resources, we cannot consider climate change to be a threat to the species now, or in the foreseeable future. A reduction in forage availability may also occur during periods of drought. However, we have no data to facilitate our understanding of what impacts this may have on the species. Additionally, the Wyoming pocket gopher has persisted within its known range since at least 1857 (Thaeler and Hinesley 1979, p. 480) despite periods of natural drought. Therefore, while there may be population variation as a result of drought, we do not have any data indicating that drought creates a threat to the Wyoming pocket gopher now, or in the foreseeable future.

Currently, livestock grazing is the most widespread type of land use across the sagebrush biome, which includes the known range of the Wyoming pocket gopher (Knick et al . 2003, p. 616; Connelly et al . 2004, pp. 7-29; Knick et al ., in press, p. 27). Several studies have shown that livestock grazing can result in reduced pocket gopher abundance and in some cases complete exclusion (Phillips 1936, p. 676; Hunter 1991, p. 117; Stromberg and Griffin 1996, p. 1205; Eviner and Chapin 2003, p. 125). Livestock grazing has the potential to negatively affect pocket gophers through a variety of mechanisms, such as soil compaction (Phillips 1936, pp. 677-678). However, direct competition for forage likely has the largest negative effect on pocket gopher populations (Phillips 1936, p. 677). Wild ungulate grazing has been found to have similar competitive effects to other small mammals (Coäte et al . 2004, p. 129), and this interaction may impact pocket gophers. However, we have no information to suggest that this competition is occurring with the Wyoming pocket gopher.

Historically, pocket gophers have been recognized by livestock producers as competitors with livestock for limited rangeland forage (Richens 1965, p. 424; Julander et al . 1969, p. 325; Turner 1969, p. 377; Laycock and Richardson 1975, p. 458). Pocket gophers primarily feed on forbs; however, diet composition can shift seasonally to include varying percentages of grasses and shrubs (see discussion above under Life History; Aldous 1951, pp. 85-86; Ward and Keith 1962, p. 747). Cattle are grazers, feeding mostly on grasses, but they will make seasonal use of forbs and shrub species (Vallentine 1990, p. 226). Domestic sheep are intermediate feeders, making high use of forbs but also using a large volume of grass and shrub species (Vallentine 1990, pp. 240-241). Horses are generalists, but seasonally their diets can be almost wholly comprised of grasses (Wagner 1983, pp. 119-120). The degree of competition between pocket gophers and livestock due to diet varies with local conditions that affect type and abundance of vegetation, stocking rates, and types of livestock (Phillips 1936, p. 676; Eviner and Chapin 2003, p. 125). We are unable to assess the levels of competition that are occurring, but competition has likely remained constant since grazing levels on BLM lands have generally been stable since 1978 (Laycock et al . 1996, p. 50). We anticipate future levels of competition from grazing to remain constant, as the recently renewed BLM Resource Management Plan for much of the range of the Wyoming pocket gopher does not include a change in past livestock stocking rates (BLM 2008, pp. 2-19).

Domestic livestock grazing will continue at present levels within the range of the Wyoming pocket gopher (BLM 2008, pp. 2-19). The current amounts, kinds, and seasons of livestock grazing use will be authorized until monitoring, field observations, ecological site inventory, or other data acceptable to the BLM indicates an adjustment to grazing use is necessary (BLM 2008, pp. 2-19). While we cannot provide an exact estimate of the foreseeable future for grazing, we expect this use to be persistent across the Wyoming pocket gopher's range for several decades.

We recognize the potential for negative impacts to Wyoming pocket gopher populations due to direct competition with livestock, but have no information about the impacts of grazing practices or grazing intensity to the species. Livestock grazing has remained consistent over time, and the Wyoming pocket gopher has continued to occupy its known range. Additionally, we are unaware of any studies linking grazing practices to population levels of the Wyoming pocket gopher. Therefore, we have no information to indicate that grazing poses a threat to the Wyoming pocket gopher now, or in the foreseeable future.

Urbanization is considered a significant threat to other species of pocket gopher, such as the Mazama pocket gopher (Service 2009b, p. 8); however, urbanization is limited within the range of the Wyoming pocket gopher. This area is largely rural, with approximately 55,000 people residing in Carbon and Sweetwater Counties in 2008 (U.S. Census Bureau 2009, p. 94), which is an average of 3 people per square mile (2.6 square kilometers). However, most of this population is concentrated in the population centers of Rock Springs, Green River, and Rawlins, which are at the edges of the potential Wyoming pocket gopher range. The BLM administers approximately half of the land in the range of the species, so urban development is precluded from those areas. Limited housing development is occurring near Wyoming pocket gopher collection sites, primarily to support gas field workers. These areas provide concentrated areas of disturbance, which create fewer impacts to the overall range of the species. The limited amount of housing across the range of the species also restricts the opportunities for domestic pet predation on Wyoming pocket gophers. We are unable to quantify a foreseeable future, but anticipate that additional urbanization will be limited based on the isolated nature of the area and the harsh environment that has not historically attracted many people. Based on the limited amount of urbanization, we do not consider it to be a significant threat to the Wyoming pocket gopher now, or in the foreseeable future.

We conclude that the range of the Wyoming pocket gopher has experienced and will continue to experience significant changes, primarily related to oil, gas, and wind development. The range is also likely to experience some changes related to climate change. Changes from other sources, including nonnative vegetation, grazing, and urbanization, may occur to a lesser degree. However, we are unable to demonstrate that these alterations to habitat will result in negative effects to the species. Examining data from studies on other species of pocket gophers' responses to similar disturbances did not provide clarity as the response appeared to vary by species. For example, the invasive Bromus tectorum may negatively affect pocket gophers, but northern pocket gophers can occur where B. tectorum is a prevalent plant species (Ostrow et al . 2002, p. 992), and the seeds of B. tectorum were occasionally found in their burrows (Cox 1989, pp. 78-80). Many species of pocket gophers increase rates of mound building in areas of disturbed vegetation, while others are not found in areas of disturbance (Moulton et al . 1983, p. 58). Therefore, predicting the potential effects of habitat disturbances or alteration on the Wyoming pocket gopher based on the responses of other pocket gophers is not possible. The species continues to occupy its known historic range despite habitat alterations that have occurred within that range, and we have no evidence of population declines.

We conclude that the best scientific and commercial information available indicates that the Wyoming pocket gopher is not now, or in the foreseeable future, threatened by the present or threatened destruction, modification, or curtailment of its habitat or range to the extent that listing under the Act as an endangered or threatened species is warranted at this time.

Overutilization is the consumptive use of an organism, where individuals are intentionally captured or taken for a variety of purposes. Examples include take for human consumption, use of feathers or fur to create garments, and capture and removal of individuals for scientific or educational examinations or study. We have no data indicating that the Wyoming pocket gopher has been, is currently being, or will be in the future, used for commercial, recreational, or educational purposes.

In the late 1970s, in Wyoming and Colorado, 228 pocket gophers of three different species were collected and euthanized to collect tissue for taxonomic delineation (Thaeler and Hinesley 1979, p. 480). Forty of the animals collected were identified as Wyoming pocket gophers, although the authors note that tissue preparation on 83 individuals was insufficient to do genetic analyses. Therefore, more Wyoming pocket gophers may have been collected but not identified. No further documented captures of the Wyoming pocket gopher occurred until 2008, when 12 individuals were trapped to collect genetic and morphological information for species determination (Griscom et al . 2010, p. 5). Two of those pocket gophers were euthanized to obtain the tissue necessary for karyotyping procedures (McDonald 2009b, pers. comm.). Trapping continued in 2009 to collect distribution and habitat information. A total of 19 individuals were captured in 2009 (Griscom 2010b, pers. comm.), with 2 individuals found dead in the traps (Griscom et al . 2010, p. 9). No other Wyoming pocket gopher mortalities from these trapping efforts were reported. Tissue samples (removing the tip of the tail) were collected from 5 individuals in 2008 and 15 individuals in 2009 prior to their subsequent release at the capture location (Griscom 2009c, pers. comm.; Griscom et al . 2010, p. 22). Some individuals may have died after release at the capture location; however, one Wyoming pocket gopher (Griscom 2009c, pers. comm.) and a pocket gopher of another species were recaptured a day or two after the tip of the tail was removed (Griscom et al . 2010, p. 11). The wounds were healing, and the pocket gophers did not appear to show any ill effects (Griscom et al . 2010, p. 11). Northern pocket gophers survived in a lab environment for several weeks after having their tails clipped (McDonald 2009a, pers. comm.). This limited evidence suggests that this tissue collection does not result in mortality.

The Wyoming Game and Fish Department (WGFD) issued collection permits for Wyoming pocket gophers for the scientific work that occurred in 2008 and 2009 (Emmerich 2009, p. 2). The review associated with the permitting process provided a protective measure to the species by limiting take to those individuals authorized to perform the work (Wyoming Game and Fish Commission (WGFC) 1998, pp. 52-8-52-9). Based on recent interest in the Wyoming pocket gopher, we anticipate that some utilization of the species related to scientific research will occur in 2010 and possibly in future years.

We could find no other information on research or scientific use of the Wyoming pocket gopher. The lack of population data for this species results in difficulties in determining whether the Wyoming pocket gopher is adversely impacted by scientific purposes. However, we do not believe overutilization to be a current or future threat because relatively few individuals have been affected by scientific research, research methodologies generally involve live captures, and available information indicates captured individuals can survive without noticeable effects.

We conclude that the best scientific and commercial information available indicates that the Wyoming pocket gopher is not now, or in the foreseeable future, threatened by overutilization for commercial, recreational, scientific, or educational purposes to the extent that listing under the Act as an endangered or threatened species is warranted at this time.

Disease and parasites have not been demonstrated to limit populations of pocket gophers (Keinath and Beauvais 2006, p. 20). In general, pocket gophers host some endo- and exo-parasites, most of which have been identified incidentally to other research (Keinath and Beauvais 2006, p. 21). In some cases, northern pocket gophers have been found with sufficient levels of botfly larvae to result in mortality, with up to 25 to 37 percent of local gopher populations affected (Keinath and Beauvais 2006, p. 21 and references therein). However, the effects of these infestations on population persistence were not provided. No research has been conducted on diseases and parasites of the Wyoming pocket gopher. Therefore, combined with the lack of population data, we have no way of assessing the current or future impact of this factor on this species. We recognize that lower levels of genetic diversity may allow a population to have greater susceptibility to diseases (Sanjayan et al . 1996, p. 1525), but we do not have information indicating that disease poses a threat to the Wyoming pocket gopher, and we do not have sufficient information to describe genetic diversity of the species. Additionally, we do not have information indicating that human activities in the area increase the susceptibility of the Wyoming pocket gopher to disease or parasites due to increased physiological stress.

Pocket gophers are subject to predation from gopher snakes ( Pituophis catenifer ), rattlesnakes ( Crotalus viridis ), long-tailed weasels ( Mustela frenata ), coyotes ( Canis latrans ), bobcats ( Lynx rufus ), badgers ( Taxidea taxus ), foxes ( Vulpes spp.), skunks ( Mephitis spp.), numerous owls (Keinath and Beauvais 2006, p. 20), and domestic pets (Stinson 2005, p. 51). However, we have no data indicating that predation limits Wyoming pocket gopher populations. Ravens ( Corvus corax ) use road networks associated with oil fields in southwestern Wyoming for foraging activities (Bui 2009, p. 31), and common raven abundance increases in association with oil and gas development in southwestern Wyoming (Holmes 2009, p. 1). However, we could find no information that ravens prey upon pocket gophers. Therefore, if raven abundance is increasing within the range of the Wyoming pocket gopher as a result of energy development activities, there is likely no effect on Wyoming pocket gophers. We were unable to find any other information to suggest that the predator-prey balance for the Wyoming pocket gopher has been affected by any anthropogenic activity, or may be affected within the forseeable future.

Based on our understanding of past and current effects, we do not anticipate the effects of disease, parasites, or predation to change for the foreseeable future.

We conclude that the best scientific and commercial information available indicates that the Wyoming pocket gopher is not now, or in the foreseeable future, threatened by disease or predation to the extent that listing under the Act as an endangered or threatened species is warranted at this time.

Under this factor, we examine whether identified threats to the Wyoming pocket gopher are adequately addressed by existing regulatory mechanisms. These mechanisms could include: (1) Local land use laws, processes, and ordinances; (2) State laws and regulations; and (3) federal laws and regulations. Regulatory mechanisms, if they exist, may preclude listing if such mechanisms are judged to adequately address the threat to the species such that listing is not warranted.

We could find no local land use laws, processes, or ordinances that provide a regulatory mechanism for the Wyoming pocket gopher. The State of Wyoming has identified the Wyoming pocket gopher as a Native Species Status 4, meaning that while populations are restricted in distribution, the species' habitat does not appear to be declining, and there are no known sensitivities to human disturbance (Oakleaf et al . 2002, p. 263). Important conservation efforts for this species identified by the WGFD are to collect more information on the species' status, trends, and habitat use. The Wyoming pocket gopher is identified in the WGFD Comprehensive Wildlife Conservation Strategy (WGFD 2005, pp. 250-251) as a species of concern, which signifies a decline or restriction to the population or its habitat or both, but confers no State protection to the species. The Wyoming pocket gopher received this designation based on restricted habitat and limited available information on the species (Emmerich 2009, p. 1). The WGFD does restrict the take of the Wyoming pocket gopher under Chapter 52 of the WGFC regulations (WGFC 1998, p. 52-9; Emmerich 2009, p. 1). This designation protects individuals of the species from take unless take is authorized by regulations or is necessary to address human health or safety (WGFC 1998, pp. 52-58). No state regulatory mechanisms provide for protection of the species' habitat.

The Wyoming pocket gopher has been identified as a sensitive species by Region 2 of the U.S. Forest Service (USFS) based on the species' rarity and potential sensitivity to disturbance (Keinath and Beauvais 2006, p. 6; USFS 2006, p. 10), although we are unaware of any occurrence of this species on USFS lands (Keinath and Beauvais 2006, p. 7). The USFS does not confer any protective regulations to identified sensitive species. The BLM in Wyoming also identifies the Wyoming pocket gopher as a sensitive species (Abbott 2009b, pers. comm.), which requires the agency to consider the welfare of these species when evaluating any action on public lands (BLM 2001, pp. 21J-22D3c(2)). The BLM has identified the Wyoming pocket gopher in NEPA documents in the areas of the Wyoming pocket gopher's distribution, such as the 2006 Atlantic Rim Final Environmental Impact Statement (BLM 2006b, p. 4-89). Project proponents for future projects on BLM lands were instrumental in collecting distributional data in 2008 and 2009 (Beauvais 2009, p. 4; Griscom et al . 2010, p. 6). However, species-specific management actions have not been developed by the BLM (Keinath and Beauvais 2006, pp. 6-8; Abbott 2010, pers. comm.). Despite the lack of regulatory mechanisms, this species continues to occupy its known range.

We anticipate no changes in the current regulatory mechanisms for the foreseeable future, unless research on the Wyoming pocket gopher indicates that regulatory mechanisms are necessary and can help prescribe specific effective protections.

We conclude that the best scientific and commercial information available indicates that the Wyoming pocket gopher is not now, or in the foreseeable future, threatened by the inadequacy of existing regulatory mechanisms to the extent that listing under the Act as an endangered or threatened species is warranted at this time. It is unclear that regulatory mechanisms in addition to those described are needed for the species based on the current understanding of threats.

Other natural or manmade factors affecting the continued existence of the Wyoming pocket gopher that we analyzed include vulnerability of small populations, use of poisons to target the species, and recreational activities. We are unaware of other factors that may affect the continued existence of the species.

The Wyoming pocket gopher is a narrow endemic species (i.e., a species whose natural occurrence is confined to a certain region and whose distribution is relatively limited). The best available scientific data suggest that this species occurs in just two counties in southwest Wyoming. Small geographic range has been identified as the most important single indicator of elevated extinction risk in mammals (Purvis et al . 2000, p. 1949; Oborny et al . 2005, p. 291; Cardillo et al . 2006, pp. 4157-4158; Cardillo et al . 2008, p. 1445; Davies et al . 2008, p. 11559). The inherent vulnerability associated with small geographic range is due to the fact that a single localized threat, whether it is manmade (e.g., development) or environmental (e.g., disease), can potentially impact the entire distribution of the species, resulting in an increased probability of extinction (Davies et al . 2008, p. 11559).

Small population size has also been identified as an important predictor of extinction vulnerability (O'Grady et al . 2004, p. 517). Although we have no information on Wyoming pocket gopher abundance, restricted geographic range frequently correlates with small population size (Purvis et al . 2000, p. 1947). Thus, it is reasonable to assume that abundance is low relative to other pocket gopher species with larger geographic ranges (e.g., northern pocket gopher). Given their restricted distribution and presumably relatively small population size, Wyoming pocket gophers are more vulnerable to demographic, environmental, and genetic stochasticity than larger, more widely distributed species, which could affect the Wyoming pocket gopher's likelihood for long-term persistence.

Wyoming pocket gopher distribution appears to be discontinuous, and it remains undetermined if a metapopulation structure (a group of spatially separated populations which interact at some level) exists for this species (Keinath and Beauvais 2006, p. 19). Based on the abilities of other pocket gophers, which is consistent in the scientific literature for all species, Wyoming pocket gophers are not thought capable of dispersing long distances and may be restricted by the energetic demands of tunneling (Hansen 1962, p. 152; Vaughan 1963, p. 371; Keinath and Beauvais 2006, p. 16). There may be some above-ground dispersal at night (Griscom 2009a, pers. comm.) or when there is snow cover (Vaughan 1963, p. 369). The patchy distribution and low dispersal capability result in a low probability for recolonization following local population extinctions (Keinath et al . 2008, p. 7). When the area over which a colonization-extinction process operates is geographically small, as is the case with Wyoming pocket gopher, a single local extinction that is not followed by recolonization can have a large impact on the occupancy of the total area (Oborny et al . 2005, p. 291).

The Wyoming pocket gopher has persisted since at least 1857 (Coues 1875, p. 138) and may never have had a large population size. The species appears to be currently distributed throughout its known range in a pattern that approximates historic distribution (see Figure 1 above). However, it appears to have several characteristics, such as small geographic range, isolated populations, and low dispersal ability, which increase the species' vulnerability to extinction from stochastic events and other threats on the landscape. Currently, we do not have information on these threats to an extent that allows us to know whether small population size allows for other manmade or environmental factors to create a threat to the Wyoming pocket gopher. Further, the historic range and persistence of the species' population size indicate the species occurs in normally low population densities. We are unable to quantify a foreseeable future for stochastic events that may have disproportionate negative effects on small population sizes. We do not anticipate the effects of these events on small population size to change, but our understanding of these effects may improve over time.

Campaigns to eliminate other species of pocket gophers are often pursued in association with development, farmlands, and ranchlands. We have no information that indicates that pocket gophers are the target of lethal control campaigns within the range of the Wyoming pocket gopher. Strychnine and Rozol are both rodenticides approved by the U.S. Environmental Protection Agency for control of pocket gophers, and these substances may create a threat to the Wyoming pocket gopher through targeted application or non-target poisonings of another species (Dickerson 2009a, pers. comm.). We are unable to show the extent to which these and similar substances are used on private lands in the area; however, rangelands, which form the majority of Wyoming pocket gopher habitat, are not typically the target of pocket gopher control measures (Dickerson 2009b, pers. comm.). Additionally, the BLM does not use pesticides or rodenticides in Wyoming to protect reclamation areas (Abbott 2009a, pers. comm.). We are unable to determine if the Wyoming pocket gopher may be targeted by, or exposed to, substances used for lethal control in the future. We are unaware of other methods that are commonly used for lethal control of pocket gopher populations. We currently do not have any information that would lead us to anticipate an increase in lethal control of the Wyoming pocket gopher for the foreseeable future.

Recreational activities within the range of the Wyoming pocket gopher include hunting, camping, hiking, horse riding, use of all-terrain vehicles, and visiting historic sites. These activities may cause elevated levels of human presence on the landscape and resultant disturbances to habitat, which were discussed in Factor A. We have no information to indicate that increased human presence related to recreation poses a threat to the Wyoming pocket gopher. We anticipate that recreational activities will continue at current or slightly increased levels within the range of the Wyoming pocket gopher for the foreseeable future.

Based on the best available information, we have no indication that other natural or manmade factors are likely to significantly threaten the existence of the species. We recognize the inherent vulnerabilities of small populations and restricted geographic range, which appear to be exhibited by the Wyoming pocket gopher. The impacts of various potential threats can be more pronounced on small or isolated populations, and we have identified numerous activities occurring on the landscape within the range of the Wyoming pocket gopher (see Factor A discussion). However, at this time, we do not have information to indicate that these activities pose a threat to the Wyoming pocket gopher. Additionally, we do not consider a small population alone to be a threat to species; rather, it can be a vulnerability that can make it more susceptible to threat factors, if they are present. Many naturally rare species have persisted for long periods within small geographic areas, and many naturally rare species exhibit traits that allow them to persist despite their small population sizes (Nevo et al . 1997, p. 388; Rubinoff and Powell 2004, p. 2547; Lawson et al . 2008, p. 927; Abeli et al . 2009, p. 3887). The Wyoming pocket gopher is one of these species, existing in a limited range since its discovery in 1857. We have no information that this rarity is working in combination with any threat factors that would cause the species to be likely to become in danger of extinction in all or a significant portion of its range in the foreseeable future. We have identified lethal control of pocket gophers and recreational activities as other manmade factors that may impact the species, but we have no information that these factors are negatively impacting the species at this time.

We conclude that the best scientific and commercial information available indicates that the Wyoming pocket gopher is not now, or in the foreseeable future, threatened by other natural or manmade factors affecting its continued existence to the extent that listing under the Act as an endangered or threatened species is warranted at this time.

As required by the Act, we considered the five factors in assessing whether the Wyoming pocket gopher is endangered or threatened throughout all or a significant portion of its range. We have carefully examined the best scientific and commercial information available regarding the status and the past, present, and future threats faced by the Wyoming pocket gopher. We reviewed the petition, information available in our files, and other published and unpublished information submitted to us by the public following our 90-day petition finding. We also consulted with Wyoming pocket gopher experts and other Federal and State resource agencies. In considering what factors might constitute threats, we must look beyond the mere exposure of the species to the factor to determine whether the species responds to the factor in a way that causes actual impacts to the species. If there is exposure to a factor, but no response, or only a positive response, that factor is not a threat. If there is exposure and the species responds negatively, the factor may be a threat and we then attempt to determine how significant a threat it is. If the threat is significant, it may drive or contribute to the risk of extinction of the species such that the species warrants listing as threatened or endangered as those terms are defined by the Act. This does not necessarily require empirical proof of a threat. The combination of exposure and some corroborating evidence of how the species is likely impacted could suffice. The mere identification of factors that could impact a species negatively is not sufficient to compel a finding that listing is appropriate; we require evidence that these factors are operative threats that act on the species to the point that the species meets the definition of threatened or endangered under the Act. We were able to quantify the foreseeable future only for energy development and scientific utilization of the species, but discussed how we anticipate each factor to change over time. We were unable to project changes to the species into the future because we do not have sufficient data to know if these factors will result in positive or negative effects to the species.

Our review of the best available scientific and commercial information pertaining to the five factors does not support the assertion that there are threats of sufficient imminence, intensity, or magnitude to indicate the Wyoming pocket gopher is in danger of extinction (endangered), or is likely to become endangered within the foreseeable future (threatened), throughout all or a significant portion of its range. Therefore, we find that listing the Wyoming pocket gopher throughout all or a significant portion of its range is not warranted at this time.

In making this finding, we recognize that the Wyoming pocket gopher, despite not being warranted for listing as endangered or threatened, may benefit from increased management emphasis due to its limited distribution and range. In particular, future oil, gas, and wind development may have positive or negative impacts to the species and should be carefully considered and monitored. We recommend precautionary measures be taken to protect the species, and that additional research be pursued to improve the understanding of the species so that the responses to future potential threats can be better understood.

After assessing whether the species is endangered or threatened throughout its range, we next consider whether a distinct vertebrate population segment (DPS) of the Wyoming pocket gopher meets the definition of endangered or is likely to become endangered in the foreseeable future (threatened).

Under the Service's Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act (61 FR 4722, February 7, 1996), three elements are considered in the decision concerning the establishment and classification of a possible DPS. These are applied similarly for additions to or removals from the Federal List of Endangered and Threatened Wildlife. These elements include: (1) The discreteness of a population in relation to the remainder of the taxon to which it belongs; (2) the significance of the population segment to the taxon to which it belongs; and (3) the population segment's conservation status in relation to the Act's standards for listing, delisting (removal from the list), or reclassification (i.e., is the population segment endangered or threatened).

As stated above, the Wyoming pocket gopher is a narrow endemic species, historically and currently found in only two counties in south-central Wyoming. Only 47 confirmed Wyoming pocket gophers have been trapped over approximately the past 40 years, and the species appears to be currently distributed throughout its known range in a pattern that approximates historic distribution (see Figure 1 above). Dispersal strategies of the Wyoming pocket gopher are unknown (see discussion under Life History above). However, in other species of pocket gophers, dispersal has been well documented (e.g., Daly and Patton 1990, p. 1291; Hafner et al . 1998, p. 281), and we have no evidence to suggest that the Wyoming pocket gopher does not disperse within its known range. Therefore, we have no evidence suggesting that the Wyoming pocket gopher is isolated in any part of its range. We determine, based on a review of the best available information, that no portion of the Wyoming pocket gopher range meets the discreteness conditions of the 1996 DPS policy. The DPS policy is clear that significance is analyzed only when a population segment has been identified as discrete. Since we found that no population segment meets the discreteness element, and therefore no population segment qualifies as a DPS under the Service's DPS policy, we will not conduct an evaluation of significance.

Having determined that the Wyoming pocket gopher does not meet the definition of an endangered or threatened species throughout its entire region, we must next consider whether there are any significant portions of the range where the Wyoming pocket gopher is in danger of extinction or is likely to become endangered in the foreseeable future.

On March 16, 2007, a formal opinion was issued by the Solicitor of the Department of the Interior (USDI), “The Meaning of ‘In Danger of Extinction Throughout All or a Significant Portion of Its Range'” (USDI 2007, entire). We have summarized our interpretation of that opinion and the underlying statutory language below. A portion of a species' range is significant if it is part of the current range of the species and it contributes substantially to the representation, resiliency, or redundancy of the species. The contribution must be at a level such that its loss would result in a decrease in the ability to conserve the species.

In determining whether a species is endangered or threatened in a significant portion of its range, we first identify any portions of the range of the species that warrant further consideration. The range of a species can theoretically be divided into portions in an infinite number of ways. However, there is no purpose to analyzing portions of the range that are not reasonably likely to be significant and endangered or threatened. To identify only those portions that warrant further consideration, we determine whether there is substantial information indicating that: (1) The portions may be significant, and (2) the species may be in danger of extinction there or likely to become so within the foreseeable future. In practice, a key part of this analysis is whether the threats are geographically concentrated in some way. If the threats to the species are essentially uniform throughout its range, no portion is likely to warrant further consideration. Moreover, if any concentration of threats applies only to portions of the species' range that are not significant, such portions will not warrant further consideration.

If we identify portions that warrant further consideration, we then determine whether the species is endangered or threatened in these portions of its range. Depending on the biology of the species, its range, and the threats it faces, the Service may address either the significance question or the status question first. Thus, if the Service considers significance first and determines that a portion of the range is not significant, the Service need not determine whether the species is endangered or threatened there. Likewise, if the Service considers status first and determines that the species is not endangered or threatened in a portion of its range, the Service need not determine if that portion is significant. However, if the Service determines both that a portion of the range of a species is significant and that the species is endangered or threatened there, the Service will specify that portion of the range as endangered or threatened under section 4(c)(1) of the Act.

The terms “resiliency,” “redundancy,” and “representation” are intended to be indicators of the conservation value of portions of the range. Resiliency of a species allows the species to recover from periodic disturbance. A species will likely be more resilient if large populations exist in high-quality habitat that is distributed throughout the range of the species in such a way as to capture the environmental variability found within the range of the species. A portion of the range of a species may make a meaningful contribution to the resiliency of the species if the area is relatively large and contains particularly high-quality habitat, or if its location or characteristics make it less susceptible to certain threats than other portions of the range. When evaluating whether or how a portion of the range contributes to resiliency of the species, we evaluate the historical value of the portion and how frequently the portion is used by the species, if possible. In addition, the portion may contribute to resiliency for other reasons—for instance, it may contain an important concentration of certain types of habitat that are necessary for the species to carry out its life-history functions, such as breeding, feeding, migration, dispersal, or wintering.

Redundancy of populations may be needed to provide a margin of safety for the species to withstand catastrophic events. This does not mean that any portion that provides redundancy is necessarily a significant portion of the range of a species. The idea is to conserve enough areas of the range such that random perturbations in the system act on only a few populations. Therefore, each area must be examined based on whether that area provides an increment of redundancy that is important to the conservation of the species.

Adequate representation ensures that the species' adaptive capabilities are conserved. Specifically, the portion should be evaluated to see how it contributes to the genetic diversity of the species. The loss of genetically based diversity may substantially reduce the ability of the species to respond and adapt to future environmental changes. A peripheral population may contribute meaningfully to representation if there is evidence that it provides genetic diversity due to its location on the margin of the species' habitat requirements.

Section 4(c)(1) of the Act requires the Service to determine whether a portion of a species' range, if not all, meets the definition of endangered or threatened. As stated above, based on the best scientific information, we find listing the Wyoming pocket gopher across its entire range is not warranted. We were unable to identify any significant portion of the range that merits additional analysis. The 31 Wyoming pocket gopher captures that occurred in 2008 and 2009 indicate that the species is currently distributed throughout its known historic range (see Figure 1 above). The limited information available on the Wyoming pocket gopher, such as the lack of population numbers and dynamics, does not allow us to determine what portion of the range, if any, contributes substantially and differentially to the long-term persistence of the species. As discussed previously, we do not know how the species is likely to respond to many potential threats (e.g., wind energy), and therefore we cannot determine if the potential threats imperil a significant portion of the species' range. Further, for those potential threats with more well-understood impacts to the species (e.g., poisoning), we could find no portion of the range in which threats are concentrated or otherwise likely to impact a significant portion of the species' range.

We do not find that the Wyoming pocket gopher is in danger of extinction now, nor is it likely to become endangered within the foreseeable future, throughout all or a significant portion of its range. Therefore, listing the species as endangered or threatened under the Act is not warranted at this time.

We request that you submit any new information concerning the status of, or threats to, the Wyoming pocket gopher to our Wyoming Ecological Services Field Office (see ADDRESSES section) whenever it becomes available. New information will help us monitor this species and encourage its conservation. If an emergency situation develops for the Wyoming pocket gopher or any other species, we will act to provide immediate protection.

A complete list of all references cited in this document is available on the Internet at http://www.regulations.gov and upon request from the Wyoming Ecological Services Field Office (see ADDRESSES section).

The primary authors of this document are staff members of the Wyoming Ecological Services Field Office (see ADDRESSES section).

The authority for this action is section 4 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq. ).