Federal Register Vol. 80, No.193,

RHS proposes to amend the current regulation for the Single Family Housing Guaranteed Loan Program (SFHGLP) on the subject of liquidation value appraisals. In order to reduce overall processing time, reduce cost, and expedite claim submission, lenders will order the liquidation value appraisal used to estimate a loss claim against the SFHGLP instead of the Agency. Specifically, SFHGLP proposes to amend 7 CFR 3555.306(f)(3), 3555.352(e), 3555.353(b)(1), and 3555.354(b)(1)(i) and (ii) and (2).

This proposed rule has been determined to be non-significant and, therefore was not reviewed by the Office of Management and Budget (OMB) under Executive Order 12866.

This proposed rule has been reviewed under Executive Order 12988, Civil Justice Reform. Except where specified, all State and local laws and regulations that are in direct conflict with this rule will be preempted. Federal funds carry Federal requirements. No person is required to apply for funding under SFHGLP, but if they do apply and are selected for funding, they must comply with the requirements applicable to the Federal program funds. This proposed rule is not retroactive. It will not affect agreements entered into prior to the effective date of the rule. Before any judicial action may be brought regarding the provisions of this rule, the administrative appeal provisions of 7 CFR part 11 must be exhausted.

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public Law 104-4, establishes requirements for Federal agencies to assess the effect of their regulatory actions on State, local, and tribal governments and the private sector. Under section 202 of the UMRA, the Agency generally must prepare a written statement, including a cost-benefit analysis, for proposed and final rules with “Federal mandates” that may result in expenditures to State, local, or tribal governments, in the aggregate, or to the private sector, of $100 million, or more, in any one year. When such a statement is needed for a rule, section 205 of the UMRA generally requires the Agency to identify and consider a reasonable number of regulatory alternatives and adopt the least costly, most cost-effective, or least burdensome alternative that achieves the objectives of the rule.

This proposed rule contains no Federal mandates (under the regulatory provisions of Title II of the UMRA) for State, local, and tribal governments or the private sector. Therefore, this rule is not subject to the requirements of sections 202 and 205 of the UMRA.

This document has been reviewed in accordance with 7 CFR part 1940, subpart G, “Environmental Program.” It is the determination of the Agency that this action does not constitute a major Federal action significantly affecting the quality of the human environment, and, in accordance with the National Environmental Policy Act of 1969, Public Law 91-190, neither an Environmental Assessment nor an Environmental Impact Statement is required.

The policies contained in this rule do not have any substantial direct effect on States, on the relationship between the national government and States, or on the distribution of power and responsibilities among the various levels of government. Nor does this rule impose substantial direct compliance costs on State and local governments. Therefore, consultation with the States is not required.

In compliance with the Regulatory Flexibility Act (5 U.S.C. 601 et seq.) the undersigned has determined and certified by signature of this document that this rule change will not have a significant impact on a substantial number of small entities. This rule does not impose any significant new requirements on Agency applicants and borrowers, and the regulatory changes affect only Agency determination of program benefits for guarantees of loans made to individuals.

Executive Order 13175 imposes requirements on RHS in the development of regulatory policies that have Tribal implications or preempt tribal laws. RHS has determined that the proposed rule does not have a substantial direct effect on one or more Indian Tribe(s) or on either the relationship or the distribution of powers and responsibilities between the Federal Government and Indian Tribes. Thus, this proposed rule is not subject to the requirements of Executive Order 13175. If a Tribe determines that this rule has implications of which RHS is not aware and would like to engage with RHS on this rule, please contact USDA's Native American Coordinator at (720) 544-2911 or [email protected].

Theses loan are subject to the provisions of Executive Order 12372, which require intergovernmental consultation with State and local officials. RHS conducts intergovernmental consultations for each SFHGLP in accordance with 2 CFR part 415, subpart C.

The program affected by this regulation is listed in the Catalog of Federal Domestic Assistance under Number 10.410, Very Low to Moderate Income Housing Loans (Section 502 Rural Housing Loans).

The information collection and record keeping requirements contained in this regulation have been approved by OMB in accordance with the Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35). The assigned OMB control number is 0570-0179.

The Agency is committed to complying with the E-Government Act, to promote the use of the Internet and other information technologies to provide increased opportunities for citizen access to Government information and services, and for other purposes.

The U.S. Department of Agriculture (USDA) prohibits discrimination against its customers, employees, and applicants for employment on the bases of race, color, national origin, age, disability, sex, gender identity, religion, reprisal, and where applicable, political beliefs, marital status, familial or parental status, sexual orientation, or all or part of an individual's income is derived from any public assistance program, or protected genetic information in employment or in any program or activity conducted or funded by the Department. (Not all prohibited bases will apply to all programs and/or employment activities.)

If you wish to file a Civil Rights program complaint of discrimination, complete the USDA Program Discrimination Complaint Form (PDF), found online at http://www.ascr.usda.gov/complaint_filing_cust.html, or at any USDA office, or call (866) 632-9992 to request the form. You may also write a letter containing all of the information requested in the form. Send your completed complaint form or letter to us by mail at U.S. Department of Agriculture, Director, Office of Adjudication, 1400 Independence Avenue SW., Washington, DC 20250-9410, by fax (202) 690-7442 or email at [email protected].

Individuals who are deaf, hard of hearing or have speech disabilities and you wish to file either an EEO or program complaint please contact USDA through the Federal Relay Service at (800) 877-8339 or (800) 845-6136 (in Spanish).

Persons with disabilities, who wish to file a program complaint, please see information above on how to contact us by mail directly or by email. If you require alternative means of communication for program information (e.g., Braille, large print, audiotape, etc.) please contact USDA's TARGET Center at (202) 720-2600 (voice and TDD).

The SFHGLP growth has been driven by tight credit markets in which lenders are reluctant to make mortgage loans without Government backing. In order to reduce the time it takes to review and pay a claim, and to increase efficiency of the loss claim process, the program is streamlining the process involved with liquidation value appraisals by requiring the lender to order the appraisal and include the costs associated with this action in the liquidation costs.

The described change was recommended by a Lean Six Sigma task force as a business process which will improve loss claim payment timeframes by requiring lenders to order liquidation value appraisals, instead of the agency doing so. It will shorten the loss claims process by at least twenty-five-percent, save approximately $203,112 or 5,850 staff hours, and allow the Customer Service Center (CSC) to focus on other stages of the liquidation process that potentially represent greater risk to the taxpayer. As currently performed today, staff will continue to review all appraisals and therefore the proposed change involves no additional program risk.

Therefore, chapter XXXV, title 7 of the Code of Federal Regulations is proposed to be amended as follows:

The proposed rule implements Section 1614 of the National Defense Authorization Act for Fiscal Year 2014, Public Law 113-66, December 26, 2013 (hereinafter NDAA 2014). Section 1614 amended section 8(d)(6)(D) of the Small Business Act, 15 U.S.C. 637(d)(6)(d), to provide that where a prime contractor has a subcontracting plan for a specific prime contract with an executive agency, as required by Section 8(d) of the Small Business Act, the prime contractor will receive credit towards its subcontracting plan goals for awards made to small business concerns at any tier under the contract. When a prime contractor awards a subcontract to a firm it is generally considered a first tier subcontract. That subcontractor may award a subcontract, which would be considered a second tier subcontract, and so on. Currently, a prime contractor generally receives credit towards its small business subcontracting plan goals for awards made at the first tier level.

Other than small business prime contractors report on their small business subcontracting activity in various ways. Some firms have individual subcontracting plans for each and every Federal prime contract that meets certain threshold requirements. Other firms have commercial plans, which is a plan that covers a firm's entire fiscal year and the firm's entire commercial production sold by either the entire company or a portion thereof (e.g., division, plant, or product line). See Federal Acquisition Regulation (FAR) § 19.701. Some firms that do business with the Department of Defense have comprehensive subcontracting plans, where the firms' negotiate goals and report on a plant, division or company-wide basis, instead on each individual Federal contract. See Defense Federal Acquisition Regulation § 219.702. Section 1614 further provides that lower tier reporting credit shall not apply where a subcontracting plan applies to more than one contract or to one contract with more than one executive agency. Section 1614 applies only when determining whether or not a prime contractor has met its individual subcontracting plan goals. Thus, Section 1614 does not apply where the prime contractor has a commercial plan or comprehensive subcontracting plan. Section 1614 does not alter the requirement that lower tier subcontractors have subcontracting plans when the subcontracting threshold amounts are met. Section 1614 must be implemented so that subcontracting dollars are only reported once for the same award to avoid double and triple counting the dollars, notwithstanding the fact that a small business subcontract may be reported under more than one subcontracting plan. Section 1614 further provides that where a prime contractor or subcontractor is required to have an individual subcontracting plan, the prime contractor or the subcontractor will review and approve subcontracting plans submitted by their subcontractors, monitor their subcontractors' compliance with the subcontracting plans, ensure that reports are submitted by their subcontractors, acknowledge receipt of subcontractors' reports, monitor subcontractor performance, and discuss subcontractor performance with subcontractors where necessary.

Section 1614 also requires that a subcontracting plan must contain a recitation of the types of records the prime contractor will maintain to demonstrate the procedures which have been adopted to ensure that subcontractors at all tiers comply with the requirements and goals in their respective subcontracting plans, including the establishment of source lists to identify small business concerns, small business concerns owned and controlled by veterans, small business concerns owned and controlled by service-disabled veterans, qualified HUBZone small business concerns, small business concerns owned and controlled by socially and economically disadvantaged individuals, and small business concerns owned and controlled by women, and efforts to identify and award subcontracts to such concerns.

SBA is also proposing to clarify that the NAICS code and corresponding size standard for a particular subcontract must appear in the solicitation for the subcontract. The current regulations only reference the subcontract itself. However, the solicitation for the subcontract must contain the size standard that a firm must represent that it meets at the time of its offer for the subcontract in order to be considered a small business concern for that subcontract. In addition, SBA is proposing to allow prime contractors and subcontractors to accept electronic size and socioeconomic representations provided the solicitation and/or subcontract require the firm making the electronic representations to verify the accuracy of the representations. Compliance with Executive Orders 12866, 13563, 12988, and 13132, the Paperwork Reduction Act (44 U.S.C. Ch. 35), and the Regulatory Flexibility Act (5 U.S.C. 601-612).

The Office of Management and Budget (OMB) has determined that this proposed rule is a significant regulatory action for the purposes of Executive Order 12866. Accordingly, the next section contains SBA's Regulatory Impact Analysis. This is not a major rule, however, under the Congressional Review Act.

The proposed regulations implement Section 1614 of the National Defense Authorization Act for Fiscal Year 2014. Section 1614(c)(3) requires the Administrator to promulgate regulations necessary to implement the Act.

The benefits and costs of the proposed regulations are minimal. Other than small business prime contractors and subcontractors already establish individual subcontracting plan goals and report on their achievements if the subcontracting plan thresholds are met. Under Section 1614, a prime contractor with an individual subcontracting plan will receive credit towards its goals for small business performance at lower tiers. Thus, there will be some costs to the prime contractor to propose subcontracting plan goals that incorporate small business performance at lower tiers, and there will also be costs to the Government to evaluate whether the prime contractor's goals adequately address maximum practicable small business subcontracting opportunity at all tiers. There may also be costs to the Government as eSRS may have to be modified to allow large business prime contractors to receive small business credit at any tier towards their subcontracting plan goals. There should not be any costs imposed on small business concerns.

Many of the proposed regulations are required to implement specific statutory provisions which require promulgation of implementing regulations. There are no other alternatives that would meet the statutory requirements.

As part of its ongoing efforts to engage stakeholders in the development of its regulations, SBA has solicited comments and suggestions from procuring agencies on how to best implement Section 1614. SBA has incorporated those comments and suggestions to the extent feasible. SBA intends to incorporate, where feasible, public input into the final rule.

For purposes of Executive Order 12988, SBA has drafted this proposed rule, to the extent practicable, in accordance with the standards set forth in section 3(a) and 3(b)(2) of that Executive Order, to minimize litigation, eliminate ambiguity, and reduce burden. This rule has no preemptive or retroactive effect.

For the purpose of Executive Order 13132, SBA has determined that this proposed rule 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 layers of government. Therefore, SBA has determined that this proposed rule has no federalism implications warranting preparation of a federalism assessment.

For purposes of the Paperwork Reduction Act (PRA), SBA has determined that this proposed rule, if adopted in final form, would not impose new government-wide reporting and record keeping requirements on other than small prime contractors and subcontractors. When this rule is implemented in the FAR, there may be a requirement to amend or create an information collection. Thus, any PRA implications as part of any proposed rulemaking implementing an SBA final rule in the FAR will be addressed in the FAR rule.

According to the Regulatory Flexibility Act (RFA), 5 U.S.C. 601, when an agency issues a rulemaking, it must prepare a regulatory flexibility analysis to address the impact of the rule on small entities. However, section 605 of the RFA allows an agency to certify a rule, in lieu of preparing an analysis, if the rulemaking is not expected to have a significant economic impact on a substantial number of small entities. The RFA defines “small entity” to include “small businesses,” “small organizations,” and “small governmental jurisdictions.” This proposed rule concerns various aspects of SBA's contracting programs. As such, the rule relates to small business concerns, but would not affect “small organizations” or “small governmental jurisdictions” because those programs generally apply only to “business concerns” as defined by SBA regulations, in other words, to small businesses organized for profit. “Small organizations” or “small governmental jurisdictions” are non-profits or governmental entities and do not generally qualify as “business concerns” within the meaning of SBA's regulations.

There are approximately 290,000 concerns registered as small business concerns in the System for Award Management (SAM) that could potentially be impacted by the implementation of Section 1614. However, we cannot say with any certainty how many will be impacted because we do not know how many of these concerns participate in government contracting as subcontractors. A firm is required to register in SAM in order to participate in Federal contracting as a prime contractor, but not for purposes of subcontracting. However, as discussed elsewhere in this proposed rule, there are no new compliance or other costs imposed by the proposed rule on small business concerns. In sum, the proposed amendments would not have a disparate impact on small businesses and would increase their opportunities to participate in federal government contracting as subcontractors without imposing any additional costs. For the reasons discussed, SBA certifies that this proposed rule would not have a significant economic impact on a substantial number of small business concerns.

For the reasons stated in the preamble, SBA proposes to amend 13 CFR parts 121 and 125 as follows:

Comments Invited

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-2015-3983; Directorate Identifier 2015-NM-141-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.

Structural fatigue damage is progressive. It begins as minute cracks, and those cracks grow under the action of repeated stresses. This can happen because of normal operational conditions and design attributes, or because of isolated situations or incidents such as material defects, poor fabrication quality, or corrosion pits, dings, or scratches. Fatigue damage can occur locally, in small areas or structural design details, or globally. Global fatigue damage is general degradation of large areas of structure with similar structural details and stress levels. Multiple-site damage is global damage that occurs in a large structural element such as a single rivet line of a lap splice joining two large skin panels. Global damage can also occur in multiple elements such as adjacent frames or stringers. Multiple-site-damage and multiple-element-damage cracks are typically too small initially to be reliably detected with normal inspection methods. Without intervention, these cracks will grow, and eventually compromise the structural integrity of the airplane, in a condition known as widespread fatigue damage (WFD). As an airplane ages, WFD will likely occur, and will certainly occur if the airplane is operated long enough without any intervention.

The FAA's WFD final rule (75 FR 69746, November 15, 2010) became effective on January 14, 2011. The WFD rule requires certain actions to prevent structural failure due to WFD throughout the operational life of certain existing transport category airplanes and all of these airplanes that will be certificated in the future. For existing and future airplanes subject to the WFD rule, the rule requires that DAHs establish a limit of validity (LOV) of the engineering data that support the structural maintenance program. Operators affected by the WFD rule may not fly an airplane beyond its LOV, unless an extended LOV is approved.

The WFD rule (75 FR 69746, November 15, 2010) does not require identifying and developing maintenance actions if the DAHs can show that such actions are not necessary to prevent WFD before the airplane reaches the LOV. Many LOVs, however, do depend on accomplishment of future maintenance actions. As stated in the WFD rule, any maintenance actions necessary to reach the LOV will be mandated by airworthiness directives through separate rulemaking actions.

In the context of WFD, this action is necessary to enable DAHs to propose LOVs that allow operators the longest operational lives for their airplanes, and still ensure that WFD will not occur. This approach allows for an implementation strategy that provides flexibility to DAHs in determining the timing of service information development (with FAA approval), while providing operators with certainty regarding the LOV applicable to their airplanes.

An evaluation by the DAH indicated that the upper chords of the upper deck floor beams are subject to WFD. The inspections and replacement in this proposed AD were developed to support the airplane's LOV of the engineering data that support the established structural maintenance program. We are proposing this AD to detect and correct fatigue cracking of the upper chords of the upper deck floor beams. Undetected cracking could result in large deflection or deformation of the upper deck floor beams, resulting in damage to wire bundles and control cables for the flight control system, and reduced controllability of the airplane. Multiple adjacent severed floor beams could result in rapid decompression of the airplane.

On September 28, 2005, we issued AD 2005-20-29, Amendment 39-14326 (70 FR 59246, October 12, 2005), for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series airplanes. AD 2005-20-29 requires repetitive inspections to detect cracks in various areas of the upper deck floor beams, and repair if necessary. AD 2005-20-29 resulted from fatigue testing that revealed severed upper chords of the upper deck floor beams due to fatigue cracking. We issued AD 2005-20-29, to detect and correct cracking in the upper chords of the upper deck floor beams. Undetected cracking could result in large deflection or deformation of the upper deck floor beams, resulting in damage to wire bundles and control cables for the flight control system, and reduced controllability of the airplane. Multiple adjacent severed floor beams could result in rapid decompression of the airplane.

AD 2005-20-29, Amendment 39-14326 (70 FR 59246, October 12, 2005), refers to Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003, as the appropriate source of service information for certain inspections. This proposed AD would require new inspections at reduced compliance times, which would end the inspections done using Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003.

We reviewed the following service information. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section of this NPRM.

• Boeing Alert Service Bulletin 747-53A2452, Revision 1, dated July 16, 2012. This service information describes procedures for repetitive open hole or surface high frequency eddy current (HFEC) inspections, as applicable, for cracks at the floor panel attachment fastener holes in certain areas and stations; repetitive surface HFEC inspections for cracks in the upper and lower chords of the upper deck floor beams at permanent fastener locations in certain areas and stations; and related investigative and corrective actions. This service information also describes procedures, for airplanes on which certain repairs or modifications are done, for repetitive open hole or surface HFEC inspections, as applicable, for cracks in the repaired and modified areas; and repair.

• Boeing Alert Service Bulletin 747-53A2852, dated June 22, 2012. This service information describes procedures for repetitive replacement of the upper chords of the upper deck floor beams, including pre-replacement inspections and corrective action, and post-replacement repetitive inspections and repair.

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between this AD and the Service Information.” For information on the procedures and compliance times, see this service information at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-3983.

The phrase “related investigative actions” is used in this proposed AD. “Related investigative actions” are follow-on actions that (1) are related to the primary actions, and (2) further investigate the nature of any condition found. Related investigative actions in an AD could include, for example, inspections.

The phrase “corrective actions” is used in this proposed AD. “Corrective actions” are actions that correct or address any condition found. Corrective actions in an AD could include, for example, repairs.

For any repair #10 or repair #13 done as specified in Boeing Alert Service Bulletin 747-53A2452, paragraph (i)(2) of this proposed AD would require that post-repair inspections be done before further flight using a method approved in accordance with the procedures specified in paragraph (o) of this AD. Operators must contact the FAA or Boeing Commercial Airplanes Organization Designation Authorization (ODA) before further flight so that the type of actions and intervals for the post-repair inspections can be determined.

Boeing Alert Service Bulletin 747-53A2452, Revision 1, dated July 16, 2012; and Boeing Alert Service Bulletin 747-53A2852, dated June 22, 2012; specify 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:

• In accordance with 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 ODA whom we have authorized to make those findings.

The compliance time for the installation specified in this proposed AD for addressing WFD was established to ensure that discrepant structure is replaced before WFD develops in airplanes. Standard inspection techniques cannot be relied on to detect WFD before it becomes a hazard to flight. We will not grant any extensions of the compliance time to complete any AD-mandated service bulletin related to WFD without extensive new data that would substantiate and clearly warrant such an extension.

We estimate that this proposed AD affects 67 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in 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 have 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 that the 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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2015-3982; Directorate Identifier 2015-NM-098-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 ten cases of the vertical stabilizer leading edge on Model 717 airplanes showing signs of fastener distress at the splice station Zfs=52.267. The affected Model 717 airplanes had accrued 22,594 through 40,985 flight hours and 15,352 through 34,766 landing cycles. Similar reports have been found on Model MD-80 and MD-90 airplanes. One Model MD-90 operator reported finding elongated fastener holes at the leading edge of the vertical stabilizer at station Zfs=52.267. The affected Model MD-90 airplane had accrued 15,555 flight-hours and 14,310 landing cycles. Two Model MD-80 operators reported finding a cracked vertical stabilizer skin at station Zfs=52.267; subsequent inspections revealed a severed front spar cap and a cracked front spar web. The affected Model MD-80 airplanes had accrued between 39,749 through 56,212 flight-hours and 32,176 through 44,001 landing cycles when the crack/anomalies were found. Missing fasteners or evidence of elongated fastener holes may be considered an indication that there are undetected cracks in the underlying vertical stabilizer structure. Boeing investigation determined that high loading occurrences, such as, but not limited to, in-flight turbulence can adversely impact the fasteners and loading at the leading edge of the vertical stabilizer.

This condition, if not corrected, could result in the structure unable to support limit load, and may lead to the loss of the vertical stabilizer.

On May 31, 2011, we issued AD 2011-12-12, Amendment 39-16719 (76 FR 35342, June 17, 2011), for certain The Boeing Company Model MD-90-30 airplanes. That AD requires a detailed inspection to detect distress and existing repairs to the leading edge structure of the vertical stabilizer at the splice at station Zfs=52.267; repetitive inspections for cracking in the front spar cap forward flanges of the vertical stabilizer, and either the aft flanges or side skins; repetitive inspections for loose and missing fasteners; and related investigative and corrective actions if necessary. We issued that AD to detect and correct such cracking damage, which could result in the structure being unable to support limit load, and could lead to the loss of the vertical stabilizer.

On July 1, 2011, we issued AD 2011-15-01, Amendment 39-16748 (76 FR 41651, July 15, 2011), for certain The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. That AD requires a detailed inspection to detect distress and existing repairs to the leading edge structure of the vertical stabilizer at the splice at station Zfs=52.267; repetitive inspections for cracking in the front spar cap forward flanges of the vertical stabilizer, and either the aft flanges or side skins; repetitive inspections for loose and missing fasteners; and related investigative and corrective actions if necessary. We issued that AD to detect and correct such cracking damage, which could result in the structure being unable to support limit load, and could lead to the loss of the vertical stabilizer.

We reviewed Boeing Alert Service Bulletin 717-55A0012, dated June 12, 2015. The service information describes procedures for a detailed inspection for any distress of the vertical stabilizer leading edge skin, a detailed inspection for any loose and missing fasteners of the spar cap, HFEC and RT inspections of the spar cap for any crack, and related investigative and corrective actions. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section of this NPRM.

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between this Proposed AD and the Service Information.”

The phrase “related investigative actions” is used in this proposed AD. “Related investigative actions” are follow-on actions that (1) are related to the primary action, and (2) further investigate the nature of any condition found. Related investigative actions in an AD could include, for example, inspections.

The phrase “corrective actions” is used in this proposed AD. “Corrective actions” are actions that correct or address any condition found. Corrective actions in an AD could include, for example, repairs.

The service bulletin 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:

• In accordance with 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) whom we have authorized to make those findings.

We estimate that this proposed AD affects 106 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in 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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

The FAA's authority to issue rules on aviation safety is found in title 49 of the United States Code (49 U.S.C.). 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.

This rulemaking is promulgated under the authority described in 49 U.S.C. 106(f), which establishes the authority of the Administrator to promulgate regulations and rules. This rulemaking also is promulgated under the authority described in 49 U.S.C. 40103, which vests the Administrator with broad authority to prescribe regulations to assign the use of airspace necessary to ensure the safety of aircraft and the efficient use of airspace, and 49 U.S.C. 44701(a)(5), which requires the Administrator to promote safe flight of civil aircraft in air commerce by prescribing regulations and minimum standards for other practices, methods, and procedures necessary for safety in air commerce and national security.

This NPRM proposes to establish a special flight rules area (SFRA) around Pearson Field Airport (Pearson Field) in which pilots would have to follow mandatory procedures. These procedures are necessary to assist in the separation of air traffic, and to ensure pilots are aware of potential traffic conflicts between aircraft operating at Pearson Field and Portland International Airport. The purpose is to ensure safety of flight for aircraft operating at Pearson Field Airport and the adjacent Portland International Airport.

Pearson Field is located on the north bank of the Columbia River in Vancouver, Washington, approximately three nautical miles west of Portland International Airport, Portland, Oregon. Pearson Field is part of the Fort Vancouver National Historic Site, and is listed on the National Register of Historic Places. It is one of the oldest airports in the United States, and the longest continually operating airport west of the Mississippi. Pearson Field does not have an air traffic control tower.

Portland International Airport is located 10 miles northeast of downtown Portland and has over 300,000 annual operations, primarily scheduled air carriers conducting operations under title 14 of the Code of Federal Regulations (14 CFR) part 121. It serves northern Oregon and southwest Washington with service to 120 cities worldwide. Due to the continued growth of Portland International Airport and the close proximity of Pearson Field, the FAA has identified safety issues.

The airspace area surrounding Pearson Field is excluded from the Portland International Airport Class C airspace area and is commonly referred to as the Pearson cutout. The runway 08 threshold at Pearson Field is directly below the instrument landing system (ILS) final approach course to Portland International Airport's runway 10L. Additionally, runway 10L was expanded to accommodate heavy aircraft and Boeing 757s. These operations increase the risk of wake turbulence events between Portland International Airport arrivals to runway 10L or departures from runway 28L/28R and aircraft operating at Pearson Field.

The Airport/Facility Directory (A/FD) lists the traffic pattern altitude at Pearson Field as 1029 feet mean sea level (MSL) or 1000 feet above ground level (AGL). The A/FD also instructs aircraft operating over the runway centerline or extended runway centerline at Pearson Field to “maintain at or below 700 feet MSL due to traffic and wake turbulence from overflying aircraft to/from Portland International Airport Runway 10L/28R.” This is because aircraft established on the Portland International Airport ILS final approach course to runway 10L pass directly over Pearson's runway 08 threshold at 1091 feet MSL (1062 feet AGL). The close proximity of the traffic pattern and the approach course create converging flight paths between aircraft on approach to Portland International Airport's runway 10L/10R and aircraft operating at Pearson Field.

These converging flight paths and the lack of vertical separation create potential safety concerns for aircraft operating at both Pearson Field and Portland International Airport, including risk of mid-air collision and wake turbulence events. There is no requirement for pilots to establish communications with air traffic control to receive traffic advisories. In particular, when Portland International Airport is operating on an east traffic flow and weather permits aircraft to operate under visual flight rules (VFR) at Pearson Field the occurrence of traffic collision avoidance system (TCAS) resolution advisories (RA) increases.

To mitigate the identified risk, FAA's Portland Approach Control took measures to increase safety, which included training controllers regarding flight paths into and out of Pearson Field, and refresher training regarding RAs, safety alerts and wake turbulence. Portland Air Traffic Control Tower established the “Pearson Advisory” position to provide traffic advisories to aircraft operating at Pearson Field. Additionally, recommended pilot communications and procedures were placed in the A/FD, which are voluntary but not required. While these mitigations have increased safety and pilot awareness, 20 TCAS RAs were reported and logged by air traffic control during calendar year 2014 and reflect an ongoing safety concern.

To address the safety concerns between traffic operating at Pearson Field and Portland International Airport, the FAA is proposing to establish a SFRA at Pearson Field by adding new subpart N to part 93, where special air traffic rules are codified. The proposed rule provides a description of the airspace area (proposed § 93.162), communication requirements in the SFRA for both inbound and outbound flights (proposed § 93.163(a)), and procedural requirements necessary to reduce the risks associated with the operation (proposed § 93.163(c)).

This action proposes to make the following voluntary practices in the A/FD and air traffic procedures applicable in the Pearson Field SFRA and mandatory for all pilots unless otherwise authorized by Air Traffic Control (ATC):

• Pilots must establish two-way radio communications with Pearson Advisory on the common traffic advisory frequency for the purpose of receiving air traffic advisories prior to entering the SFRA or taxiing onto the runway for departure. Additionally, pilots must continuously monitor the frequency at all times while operating within the designated airspace.

• When operating over the extended centerline of Pearson Field Runway 8/26, pilots must maintain an altitude at or below 700 feet MSL.

• Pilots must obtain the Pearson Field weather prior to establishing two-way communications with Pearson Advisory.

• Pilots must remain outside Portland Class C Airspace.

• Pilots must make a right-hand traffic pattern when operating to/from Pearson Field Runway 26.

• Pilots may operate in the area without establishing two-way radio communication, in the event of radio failure, provided that weather conditions at Pearson Field are at or above basic VFR weather minimums.

Changes to Federal regulations must undergo several economic analyses. First, Executive Order 12866 and Executive Order 13563 direct that each Federal agency shall propose or adopt a regulation only upon a reasoned determination that the benefits of the intended regulation justify its costs. Second, the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires agencies to analyze the economic impact of regulatory changes on small entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits agencies from setting standards that create unnecessary obstacles to the foreign commerce of the United States. In developing U.S. standards, the Trade Act requires agencies to consider international standards and, where appropriate, that they be the basis of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies to prepare a written assessment of the costs, benefits, and other effects of proposed or final rules that include a Federal mandate likely to result in the expenditure by State, local, or tribal governments, in the aggregate, or by the private sector, of $100 million or more annually (adjusted for inflation with base year of 1995). This portion of the preamble summarizes the FAA's analysis of the economic impacts of this proposed rule.

Department of Transportation Order DOT 2100.5 prescribes policies and procedures for simplification, analysis, and review of regulations. If the expected cost impact is so minimal that a proposed or final rule does not warrant a full evaluation, this order permits that a statement to that effect and the basis for it to be included in the preamble if a full regulatory evaluation of the cost and benefits is not prepared. Such a determination has been made for this proposed rule. The reasoning for this determination follows:

Due to the continued growth of Portland International Airport and the close proximity of Pearson Field, safety issues have been identified. To address the safety concerns between traffic operating at Pearson Field and Portland International Airport, the FAA is proposing to establish a SFRA at Pearson Field in part 93. The proposed rule provides a description of the area, communication requirements for both inbound and outbound flights, and procedural requirements necessary to reduce the risks associated with the operation.

Currently, pilots voluntarily comply with procedures in the A/FD, to establish two-way radio communications with Pearson Advisory, and to maintain at or below 700 feet above mean sea level when operating over the extended centerline of Pearson Field Runway 8/26. Additionally, air traffic control instructs pilots on Pearson advisory to obtain the Pearson Field weather, and to remain outside Portland Class C Airspace. As a result of being required to remain outside of Portland's Class C Airspace, pilots must make a non-standard right traffic pattern if landing on runway 26 at Pearson Field. Twenty TCAS resolution advisories (RAs) were reported and logged by air traffic control during calendar year 2014 reflecting an ongoing safety concern. By making the voluntary compliance mandatory, the FAA expects a decrease in the occurrence of, and will avoid an increase in, RAs. Thus, the cost of the rule would be minimal.

The FAA has, therefore, determined that this proposed rule is not a “significant regulatory action” as defined in section 3(f) of Executive Order 12866, and is not “significant” as defined in DOT's Regulatory Policies and Procedures.

The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) establishes “as a principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisdictions subject to regulation. To achieve this principle, agencies are required to solicit and consider flexible regulatory proposals and to explain the rationale for their actions to assure that such proposals are given serious consideration.” The RFA covers a wide range of small entities, including small businesses, not-for-profit organizations, and small governmental jurisdictions.

Agencies must perform a review to determine whether a rule will have a significant economic impact on a substantial number of small entities. If the agency determines that it will, the agency must prepare a regulatory flexibility analysis as described in the RFA.

However, if an agency determines that a rule is not expected to have a significant economic impact on a substantial number of small entities, section 605(b) of the RFA provides that the head of the agency may so certify and a regulatory flexibility analysis is not required. The certification must include a statement providing the factual basis for this determination, and the reasoning should be clear.

The FAA believes that this proposed rule does not have a significant economic impact on a substantial number of small entities for the following reasons. With this proposed rule, the procedures and voluntary practices already in place would become mandatory. The intended effect of this action is to mitigate the identified risk by establishing requirements necessary when operating within an established area at Pearson Field, and to increase overall system efficiency and safety; the expected outcome will have only a minimal impact on any small entity affected by this rulemaking action.

Therefore, as provided in section 605(b), the head of the FAA certifies that this rulemaking will not result in a significant economic impact on a substantial number of small entities.

The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal agencies from establishing standards or engaging in related activities that create unnecessary obstacles to the foreign commerce of the United States. Pursuant to these Acts, the establishment of standards is not considered an unnecessary obstacle to the foreign commerce of the United States, so long as the standard has a legitimate domestic objective, such as the protection of safety, and does not operate in a manner that excludes imports that meet this objective. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards. The FAA has assessed the potential effect of this proposed rule and determined that the rule would protect safety and is not considered an unnecessary obstacle to foreign commerce.

Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires each Federal agency to prepare a written statement assessing the effects of any Federal mandate in a proposed or final agency rule that may result in an expenditure of $100 million or more (in 1995 dollars) in any one year by State, local, and tribal governments, in the aggregate, or by the private sector; such a mandate is deemed to be a “significant regulatory action.” The FAA currently uses an inflation-adjusted value of $155 million in lieu of $100 million. This proposed rule does not contain such a mandate; therefore, the requirements of Title II of the Act do not apply.

The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires that the FAA consider the impact of paperwork and other information collection burdens imposed on the public. The FAA has determined that there is no new requirement for information collection associated with this notice of proposed rulemaking.

In keeping with U.S. obligations under the Convention on International Civil Aviation, it is FAA policy to conform to ICAO Standards and Recommended Practices to the maximum extent practicable. The FAA has reviewed the corresponding ICAO Standards and Recommended Practices and has identified no corresponding standards with these regulations.

FAA Order 1050.1E identifies FAA actions that are categorically excluded from preparation of an environmental assessment or environmental impact statement under the National Environmental Policy Act in the absence of extraordinary circumstances. The FAA has determined this rulemaking action qualifies for the categorical exclusion identified in paragraph 312f and involves no extraordinary circumstances.

The FAA has analyzed this proposed rule under the principles and criteria of Executive Order 13132, Federalism. The agency has determined that this action would not have a substantial direct effect on the States, or the relationship between the Federal Government and the States, or on the distribution of power and responsibilities among the various levels of government, and, therefore, would not have Federalism implications.

The FAA analyzed this proposed rule under Executive Order 13211, Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use (May 18, 2001). The agency has determined that it would not be a “significant energy action” under the executive order and would not be likely to have a significant adverse effect on the supply, distribution, or use of energy.

Executive Order 13609, Promoting International Regulatory Cooperation, (77 FR 26413, May 4, 2012) promotes international regulatory cooperation to meet shared challenges involving health, safety, labor, security, environmental, and other issues and to reduce, eliminate, or prevent unnecessary differences in regulatory requirements. The FAA has analyzed this action under the policies and agency responsibilities of Executive Order 13609, and has determined that this action would have no effect on international regulatory cooperation.

The FAA invites interested persons to participate in this rulemaking by submitting written comments, data, or views. The agency also invites comments relating to the economic, environmental, energy, or federalism impacts that might result from adopting the proposals in this document. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should send only one copy of written comments, or if comments are filed electronically, commenters should submit only one time.

The FAA will file in the docket all comments it receives, as well as a report summarizing each substantive public contact with FAA personnel concerning this proposed rulemaking. Before acting on this proposal, the FAA will consider all comments it receives on or before the closing date for comments. The agency may change this proposal in light of the comments it receives.

Proprietary or Confidential Business Information: Commenters should not file proprietary or confidential business information in the docket. Such information must be sent or delivered directly to the person identified in the FOR FURTHER INFORMATION CONTACT section of this document, and marked as proprietary or confidential. If submitting information on a disk or CD ROM, mark the outside of the disk or CD ROM, and identify electronically within the disk or CD ROM the specific information that is proprietary or confidential.

Under 14 CFR 11.35(b), if the FAA is aware of proprietary information filed with a comment, the agency does not place it in the docket. It is held in a separate file to which the public does not have access, and the FAA places a note in the docket that it has received it. If the FAA receives a request to examine or copy this information, it treats it as any other request under the Freedom of Information Act (5 U.S.C. 552). The FAA processes such a request under Department of Transportation procedures found in 49 CFR part 7.

An electronic copy of rulemaking documents may be obtained from the Internet by—

• Searching the Federal eRulemaking Portal (http://www.regulations.gov);

• Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies or

• Accessing the Government Printing Office's Web page at http://www.fdsys.gov.

Copies may also be obtained by sending a request to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence Avenue SW., Washington, DC 20591, or by calling (202) 267-9677. Commenters must identify the docket or notice number of this rulemaking.

All documents the FAA considered in developing this proposed rule, including economic analyses and technical reports, may be accessed from the Internet through the Federal eRulemaking Portal referenced above.

The Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA) requires FAA to comply with small entity requests for information or advice about compliance with statutes and regulations within its jurisdiction. A small entity with questions regarding this document may contact its local FAA official, or the person listed under the FOR FURTHER INFORMATION CONTACT heading at the beginning of the preamble. To find out more about SBREFA on the Internet, visit http://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

In consideration of the foregoing, the Federal Aviation Administration proposes to amend chapter I of title 14, Code of Federal Regulations as follows:

Throughout this document wherever “we,” “us,” or “our” is used, we mean the EPA.

On June 22, 2010, the EPA revised the primary SO2 NAAQS (hereafter the 2010 SO2 NAAQS) to establish a new 1-hour standard, with a level of 75 parts per billion, based on the 3-year average of the annual 99th percentile of 1-hour daily maximum concentrations (75 FR 35520). Each state must submit the i-SIP within three years after the promulgation of a new or revised NAAQS. Section 110(a)(2) of the CAA includes a list of specific elements the i-SIP must meet.

On April 23, 2013, the TCEQ submitted an i-SIP for the 2010 SO2 NAAQS. On September 13, 2013, the EPA issued guidance addressing the i-SIP elements for all NAAQS.1 This guidance doesn't address CAA section 110(a)(2)(D)(i)(I), which concerns interstate pollution transport affecting attainment and maintenance of the NAAQS.

The EPA is proposing approval of the April 23, 2013 submission for the applicable requirements of the 2010 SO2 NAAQS. The EPA is not proposing any action at this time regarding the interstate transport provisions portions of section 110(a)(2)(D)(i)(I) pertaining to nonattainment or interference with maintenance of the NAAQS in other States and the portion of 110(a)(2)(D)(i)(II) regarding visibility protection. We intend to take action as to whether the Texas SIP meets the requirements of 110(a)(2)(D)(i)(I) in a later action. In a separate action, we proposed to disapprove the portion of the Texas SO2 i-SIP for CAA section 110(a)(2)(D)(i)(II) pertaining to the visibility protection (79 FR 74818, December 16, 2014). The EPA will take final action on the portion of CAA section 110(a)(2)(D)(i)(II) pertaining to visibility protection of the Texas SO2 i-SIP in a future rulemaking. EPA notes that the Agency is not approving any specific rule, but rather proposing that Texas' already approved SIP meets certain CAA requirements.

Below is a summary of the EPA's evaluation of the Texas i-SIP for each applicable element of CAA section 110(a)(2) A-M.2 Texas provided a demonstration of how the existing Texas i-SIP met all the requirements of the 2010 SO2 NAAQS on May 09, 2013. This SIP submission became complete by operation of law on November 09, 2013. See CAA section 110(k)(1)(B).

(A) Emission limits and other control measures: The CAA § 110(a)(2)(A) requires SIPs to include enforceable emission limitations and other control measures, means or techniques (including economic incentives such as fees, marketable permits, and auctions of emissions rights), as well as schedules and timetables for compliance, as may be necessary or appropriate to meet the applicable requirements of this Act and other related matters as needed to implement, maintain and enforce each of the NAAQS.3

The Texas Clean Air Act (TCAA) provides the Texas Commission on Environmental Quality (TCEQ), its Chairman, and its Executive Director with broad legal authority. They can adopt emission standards and compliance schedules applicable to regulated entities; emission standards and limitations and any other measures necessary for attainment and maintenance of national standards; and, enforce applicable laws, regulations, standards and compliance schedules, and seek injunctive relief. This authority has been employed in the past to adopt and submit multiple revisions to the Texas State Implementation Plan. The approved SIP for Texas that satisfies the infrastructure requirements of CAA section 110(a)(2) for the 2010 SO2 NAAQS is documented at 40 CFR part 52.2270, Subpart SS. TCEQ's air quality rules and standards are codified at Title 30, Part 1 of the Texas Administrative Code (TAC). Numerous parts of the regulations codified into 30 TAC necessary for implementing and enforcing the NAAQS have been adopted into the SIP.

(B) Ambient air quality monitoring/data system: The SIP must provide for establishment and implementation of ambient air quality monitors, collection and analysis of monitoring data, and providing such data to the EPA upon request.

The TCAA provides the authority allowing the TCEQ to collect air monitoring data, quality-assure the results, and report the data. TCEQ maintains and operates a monitoring network to measure ambient levels of SO2 and submits an annual Network Assessment to the EPA with monitoring requirements. TCEQ's 2014 Air Monitoring Network Plan is the most recent EPA-approved plan and was approved by the EPA on January 14, 2015.4 All monitoring data is measured using the EPA approved methods and subject to the EPA quality assurance requirements. Federally required monitoring is conducted under an EPA-approved Quality Assurance Project Plan (QAPP). The TCEQ Web site provides the monitor locations and posts past and current concentrations of criteria pollutants measured in the State's network of monitors.5 TCEQ submits all required data to the EPA, following the EPA regulations. Previously the Texas statewide monitoring network was approved into the SIP on March 7, 1978 (43 FR 9275).

(C) Program for enforcement: The CAA § 110(a)(2)(C) requires SIPs to include the following three elements: (1) A program providing for enforcement of the measures in paragraph A above; (2) a program for the regulation of the modification and construction of stationary sources as necessary to protect the applicable NAAQS (i.e., state-wide permitting of minor sources); and (3) a permit program to meet the major source permitting requirements of the CAA (for areas designated as attainment or unclassifiable for the NAAQS).6

(1) Enforcement of SIP Measures. As noted in (A), the TCAA provides authority for the TCEQ, its Chairman, and its Executive Director to enforce the requirements any regulations, permits or final compliance orders as well as general enforcement powers. Among other things, they can file lawsuits to compel compliance with the statutes and regulations; commence civil actions, issue field citation; conduct investigations of regulated entities; collect criminal and civil penalties; develop and enforce rules and standards related to protection of air quality; issue compliance orders; pursue criminal prosecutions; investigate, enter into remediation agreements; and issue emergency cease and desist orders. The TCAA also provides additional enforcement authorities and funding mechanisms.

(2) Minor New Source Review (NSR). Section 110(a)(2)(C) also requires that the SIP include measures to regulate construction and modification of stationary sources to protect the NAAQS. The Texas minor NSR permitting requirements are approved as part of the SIP.7

(3) Prevention of Significant Deterioration (PSD) permit program. Texas's PSD portion of the SIP covers all NSR regulated pollutants as well as the requirements for the 2010 SO2 NAAQS and has been approved by the EPA.8 Texas has a SIP-approved PSD and nonattainment NSR permitting program that contains requirement for sources of air pollutants to obtain an approved permit before beginning construction of a facility and before modifying an existing facility (79 FR 66626, November 10, 2014).

(D) Interstate and international transport: The requirements for the interstate transport of SO2 emissions are that the SIP contain adequate provisions prohibiting emissions to other states which will (1) contribute significantly to nonattainment of the NAAQS, (2) interfere with maintenance of the NAAQS, (3) interfere with measures required to prevent significant deterioration or (4) interfere with measures to protect visibility (CAA 110(a)(2)(D)(i)). In addition, States must comply with requirements to prevent transport of international air pollution (CAA section 110(a)(2)(D)(ii)).

The Texas i-SIP submittal discussed the requirements of the CAA section 110(a)(D). We plan to evaluate and take action on the portion of the i-SIP pertaining to emissions which will contribute significantly to nonattainment or interfere with maintenance of the NAAQS at a later time. As noted above, we proposed to disapprove the portion of the SIP addressing interstate transport and visibility protection in an earlier action (80 FR 74818, December 16, 2014).

Because Texas has a fully approved Prevention of Significant Deterioration (PSD) SIP addressing all regulated new source review pollutants, we propose to approve the transport portion of the submittal. Revisions to the PSD SIP were approved on November 10, 2014 (79 FR 66626).

CAA section 110(a)(2)(D)(ii) requires that the SIP contain adequate provisions insuring compliance with the applicable requirements of section 126 (relating to interstate pollution abatement) and 115 (relating to international pollution abatement). Texas meets the section 126 requirements as it has a fully approved PSD SIP and no source or sources have been identified by the EPA as having any interstate impacts under section 126 in any pending action related to any air pollutant. Texas meets the section 115 requirements as there are no final findings by the EPA that Texas air emissions affect other countries. Therefore, we propose to approve the portion of the Texas SO2 i-SIP pertaining to CAA section 110(a)(2)(D)(ii).

(E) Adequate authority, resources, implementation, and oversight: The SIP must provide for the following: (1) Necessary assurances that the state (and other entities within the state responsible for implementing the SIP) will have adequate personnel, funding, and authority under state or local law to implement the SIP, and that there are no legal impediments to such implementation; (2) requirements relating to state boards; and (3) necessary assurances that the state has responsibility for ensuring adequate implementation of any plan provision for which it relies on local governments or other entities to carry out that portion of the plan.

Both elements (A) and (E) herein address the requirement that there is adequate authority to implement and enforce the SIP and that there are no legal impediments.

This i-SIP submission for the 2010 SO2 NAAQS describes the SIP regulations governing the various functions of personnel within the TCEQ, including the administrative, technical support, planning, enforcement, and permitting functions of the program.

With respect to funding, TCAA requires TCEQ establish an emissions fee schedule for sources in order to fund the reasonable costs of administering various air pollution control programs and authorizes TCEQ to collect additional fees necessary to cover reasonable costs associated with processing of air permit applications. The EPA conducts periodic program reviews to ensure that the state has adequate resources and funding to among other things implement and enforce the SIP.

As required by the CAA, the SIP stipulates that any board or body, which approves permits or enforcement orders, must have at least a majority of members who represent the public interest and do not derive any “significant portion” of their income from persons subject to permits and enforcement orders or who appear before the board on issues related to the CAA. The members of the board or body, or the head of an agency with similar powers, are required to adequately disclose any potential conflicts of interest.

With respect to assurances that the States has responsibility to implement the SIP adequately when it authorizes local or other agencies to carry out portions of the plan, the Texas statutes and the SIP designate the TCEQ as the primary air pollution control agency, and the TCEQ maintains authority to ensure implementation of any applicable plan portion.

(F) Stationary source monitoring system: The SIP must provide the establishment of a system to monitor emissions from stationary sources and to submit periodic emission reports. It must require the installation, maintenance, and replacement of equipment, and the implementation of other necessary steps, by owners or operators of stationary sources, to monitor emissions from sources. The SIP shall also require periodic reports on the nature and amounts of emissions and emissions-related data from sources, and require that the state correlate the source reports with emission limitations or standards established under the CAA. These reports must be made available for public inspection at reasonable times.

The TCAA authorizes the TCEQ to require persons engaged in operations which result in air pollution to monitor or test emissions and to file reports containing information relating to the nature and amount of emissions. There also are SIP regulations pertaining to sampling and testing and requirements for reporting of emissions inventories. In addition, SIP rules establish general requirements for maintaining records and reporting emissions.

The TCEQ uses this information, in addition to information obtained from other sources, to track progress towards maintaining the NAAQS, developing control and maintenance strategies, identifying sources and general emission levels, and determine compliance with SIP regulations and additional EPA requirements. The SIP requires this information be made available to the public. Provisions concerning the handling of confidential data and proprietary business information are included in the SIP's regulations. These rules specifically exclude from confidential treatment any records concerning the nature and amount of emissions reported by sources.

(G) Emergency authority: The SIP must provide for authority to address activities causing imminent and substantial endangerment to public health or welfare or the environment and to include contingency plans to implement such authorities as necessary.

The TCAA provides TCEQ with authority to address environmental emergencies, and TCEQ has contingency plans to implement emergency episode provisions. Upon a finding that any owner/operator is unreasonably affecting the public health, safety or welfare, or the health of animal or plant life, or property, TCAA authorizes TCEQ to, after a reasonable attempt to give notice, declare a state of emergency and issue without hearing an emergency special order directing the owner/operator to cease such pollution immediately. The TCEQ may issue emergency orders, or issue or suspend air permits as required by an air pollution emergency.

(H) Future SIP revisions: States must have the authority to revise their SIPs in response to changes in the NAAQS, availability of improved methods for attaining the NAAQS, or in response to an EPA finding that the SIP is substantially inadequate to attain the NAAQS.

The TCAA authorizes the TCEQ to revise its SIP, as necessary, to account for revisions of an existing NAAQS, establishment of a new NAAQS, to attain and maintain the NAAQS, to abate air pollution, to adopt more effective methods of attaining the NAAQS, and to respond to the EPA SIP calls concerning NAAQS adoption or implementation. TCEQ regularly revises the Texas SIP in response to revisions of the NAAQS and the EPA rules.

(I) Nonattainment areas: The CAA section 110(a)(2)(I) requires that in the case of a plan or plan revision for areas designated as nonattainment areas, states must meet applicable requirements of Part D of the CAA, relating to SIP requirements for designated nonattainment area. SIP revisions that implement the control strategies necessary to bring a nonattainment area into attainment of the NAAQSs are not required by CAA to be submitted within three years of the promulgation of a new or revised NAAQS. Therefore, § 110(a)(1) does not require this element to be demonstrated as part of an infrastructure SIP submittal (73 FR 16025, at 16206).

(J) Consultation with government officials, public notification, PSD and visibility protection: The SIP must meet applicable requirements of section 121: (1) Relating to interagency consultation regarding certain CAA requirements; section 127 (2) relating to public notification of NAAQS exceedances and related issues; and, part C relating to (3) prevention of significant deterioration of air quality and visibility protection.

(1) Interagency consultation: As required by the TCAA, there must be a public hearing before the adoption of any regulations or emission control requirements and all interested persons are given a reasonable opportunity to submit data, view, or arguments orally or in writing and to examine witnesses testifying at the hearing. The TCEQ has established public processes for all SIP revisions and permitting programs. The TCEQ consults with other agencies, local agencies, and governmental organizations, as well as with the environmental agencies of other states regarding air quality concerns.

(2) Public Notification: This i-SIP submission from Texas provides the SIP regulatory citations requiring the TCEQ to regularly notify the public of instances or areas in which any NAAQS are exceeded. Included in the SIP are the rules for TCEQ to advise the public of the health hazard associated with such exceedances; and enhance public awareness of measures that can prevent such exceedances and of ways in which the public can participate in the regulatory and other efforts to improve air quality. In addition, as discussed for infrastructure element B above, the TCEQ air monitoring Web site provides quality data for each of the monitoring stations in Texas; this data is provided instantaneously for certain pollutants, such as ozone. The Web site also provides information on the health effects of lead, ozone, particulate matter, and other criteria pollutants.

(3) PSD and Visibility Protection: All major sources in Texas are subject to Texas' SIP-approved PSD program. The PSD requirements here are the same as those addressed under (C). Texas submitted a SIP revision to address Regional Haze, including a long-term strategy to address visibility impairment for each Class I area that may be impacted by emission from Texas facilities. Texas SIP requirements relating to visibility and regional haze are not affected when the EPA establishes or revises a NAAQS. Therefore, the EPA believes that there are no new visibility protection requirements due to the revision of the NAAQS, and consequently there are no newly applicable visibility protection obligations pursuant to infrastructure element (J) after the promulgation of a new or revised NAAQS.

(K) Air quality and modeling/data: The SIP must provide for performing air quality modeling, as prescribed by the EPA, to predict the effects on ambient air quality of any emissions of any NAAQS pollutant, and for submission of such data to the EPA upon request.

The TCEQ has the power and duty, under the TCAA to investigate and develop facts providing for the functions of environmental air quality assessments. Air quality modeling is conducted during development of revisions to the Texas SIP, as appropriate for the State to demonstrate attainment with required NAAQS. Modeling is also a part of the NSR permitting program. Texas has the ability to perform modeling for the primary and secondary SO2 standards and other NAAQS criteria pollutant on a case-by-case permit basis consistent with their SIP-approved PSD rules and with the EPA guidance. Upon request, Texas will submit current and future air quality modeling data to the EPA.

(L) Permitting Fees: The SIP must require each major stationary source to pay permitting fees to the permitting authority, as a condition of any permit required under the CAA, to cover the cost of reviewing and acting upon any application for such a permit, and, if the permit is issued, the costs of implementing and enforcing the terms of the permit. The fee requirement applies until a fee program established by the state pursuant to Title V of the CAA, relating to operating permits, is approved by the EPA.

The TCEQ assesses fees for reviewing permit applications and for enforcing the terms and conditions of permits. See element (E) above for the description of the mandatory collection of permitting fees outlined in the SIP.

(M) Consultation/participation by affected local entities: The SIP must provide for consultation and participation by local political subdivisions affected by the SIP.

The TCEQ has several cooperative agreements and Memoranda of Understanding with various other state and local agencies and organizations. Consultation with a variety of different organizations is a regular part of the TCEQ process for developing a SIP. See element J herein for a discussion of the SIP's public participation process, the authority to advise and consult, and the PSD SIP's public participation requirements. Additionally, the TCAA also requires initiation of cooperative action between local authorities and the TCEQ, between one local authority and another, or among any combination of local authorities and the TCEQ for control of air pollution in areas having related air pollution problems that overlap the boundaries of political subdivisions, and entering into agreements and compacts with adjoining states and Indian tribes, where appropriate.

The EPA is proposing to approve the April 23, 2013, infrastructure SIP submission from Texas, which addresses the requirements of CAA sections 110(a)(1) and (2) as applicable to the 2010 SO2 NAAQS. Specifically, the EPA is proposing to approve the following infrastructure elements, or portions thereof: 110(a)(2)(A), (B), (C), (D)(i)(II) (PSD portion), D(ii), (E), (F), (G), (H), (J), (K), (L), and (M). The EPA is not proposing action on: The portion pertaining to section 110(a)(2)(D)(i)(I), which concerns interstate pollution transport affecting attainment and maintenance of the NAAQS and the portion pertaining to section 110(a)(2)(D)(i)(II) pertaining to visibility protection.

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely proposes to approve state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:

• Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);

• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and

• Does not provide the EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

The EPA is not proposing to approve this infrastructure SIP certification to apply on any Indian reservation land or in any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, this proposed approval of an infrastructure SIP certification does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), nor will it impose substantial direct costs on tribal governments or preempt tribal law.

I. Background

Section 172(c)(1) of the CAA provides that SIPs for nonattainment areas must include reasonably available control measures (RACM), including reasonably available control technology (RACT), for sources of emissions. Section 182(b)(2)(A) provides that for certain ozone nonattainment areas, states must revise their SIP to include RACT for sources of volatile organic compound (VOC) emissions covered by a CTG document issued after November 15, 1990 and prior to the area's date of attainment. EPA defines RACT as “the lowest emission limitation that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility.” 44 FR 53761 (September 17, 1979).

CTGs are documents issued by EPA intended to provide state and local air pollution control authorities information to assist them in determining RACT for VOC from various sources. Section 183(e)(3)(c) provides that EPA may issue a CTG in lieu of a national regulation as RACT for a product category where EPA determines that the CTG will be substantially as effective as regulations in reducing emissions of VOC, which contribute to ozone levels, in ozone nonattainment areas. The recommendations in the CTG are based upon available data and information and may not apply to a particular situation based upon the circumstances.

In 1977, EPA published a CTG for automobile and light-duty truck assembly coatings. After reviewing the 1977 CTG for this industry, conducting a review of currently existing state and local VOC emission reduction approaches for this industry, and taking into account any information that has become available since then, EPA developed a new CTG entitled Control Techniques Guidelines for Automobile and Light-duty Assembly Coatings (Publication No. EPA 453/R-08-006; September 2008).

States can follow the CTG and adopt state regulations to implement the recommendations contained therein. Alternatively, states can adopt a negative declaration documenting that there are no sources or emitting facilities within the state to which the CTG is applicable. The negative declaration must go through the same public review process as any other SIP submittal.

On July 15, 2015, the Maryland Department of the Environment (MDE) submitted to EPA a SIP revision concerning a negative declaration for the Automobile and Light-Duty Truck Assembly Coatings CTG. MDE stated that the state previously had one source to which this CTG was applicable; however, the source had permanently shut down and dismantled all their equipment as of September 2005.

EPA reviewed an inspection report provided by MDE indicating that the sole source to which this CTG would have been applicable did indeed permanently shut down in 2005. Additionally, EPA conducted an internet search of key terms relevant to the Automobile and Light-Duty Truck Assembly Coatings CTG and confirmed that there are no sources or emitting facilities in the State of Maryland to which this CTG is applicable.

EPA is proposing to approve the Maryland SIP revision concerning the negative declaration for the Automobile and Light-Duty Truck Assembly Coatings CTG, which was submitted on July 15, 2015. EPA is soliciting public comments on the issues discussed in this document. These comments will be considered before taking final action.

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

• Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);

• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and

• Does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this proposed rule concerning Maryland's negative declaration for the Automobile and Light-Duty Truck Assembly Coatings CTG, does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP is not approved to apply in Indian country located in the state, and EPA notes that it will not impose substantial direct costs on tribal governments or preempt tribal law.

On July 23, 2015, NHTSA published an ANPRM (80 FR 43663) pertaining to a petition for rulemaking from Ms. Marianne Karth and the Truck Safety Coalition (petitioners) regarding possible amendments to the Federal motor vehicle safety standards (FMVSSs) relating to rear impact (underride) guards (FMVSS Nos. 223 and 224). The petitioners requested that NHTSA require underride guards on vehicles not currently required by the FMVSSs to have guards, notably, single unit trucks, and improve the standards' performance requirements for all guards. The ANPRM requested comment on NHTSA's estimated cost and benefits of requirements for underride guards on single unit trucks, and for retroreflective material on the rear and sides of the vehicles to improve the conspicuity of the vehicles to other motorists.1 NHTSA provided a 60-day comment period for the ANPRM, which closed September 21, 2015.

NHTSA is reopening the comment period for the ANPRM for 30 days.2 NHTSA believes that a 30 day period is sufficient and balances the interests of encouraging public participation in the rulemaking process with the desire to not unnecessarily delay key decisions by NHTSA about the rulemaking and attainment of the potential societal benefits associated with a final rule.

Accordingly, the public comment closing dates for DOT Docket No. NHTSA-2015-0070 (RIN 2127-AL57) is reopened for 30 days as indicated in the DATES section of this document. NHTSA notes that the 30 day period is in addition to the time that has passed since the original September 21 comment closing date until today. Thus, all in all, more than 30 days has been provided. It is further noted that the agency will consider late comments to the extent possible.

Background

Section 4(b)(3)(B) of the 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 contains substantial scientific or commercial information that listing the species may be warranted, we make a finding within 12 months of the date of receipt of the petition. In this finding, we will 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 December 30, 1982, we published a notice of review, which determined the desert tortoise (Gopherus agassizii) throughout its range in the United States and Mexico to be a Category 2 Candidate species (47 FR 58454); this determination was reaffirmed on September 18, 1985 (50 FR 37958). Category 2 Candidate status was granted to species for which information in our possession indicated that a proposed listing as threatened or endangered was possibly appropriate, but for which sufficient data were not available to make a determination of listing status under the Act. On April 2, 1990, we issued a final rule designating the Mojave population of the desert tortoise (occurring north and west of the Colorado River) as a threatened species under the Act (55 FR 12178). Currently, the Mojave population of the desert tortoise is recognized as a distinct population segment (DPS) under the Act. As part of the Mojave DPS rulemaking, we designated any desert tortoise from the Sonoran population as threatened when observed outside of its known range, due to similarity of appearance under section 4(e) of the Act. On December 5, 1996, we published a rule that discontinued the practice of keeping a list of Category 2 Candidate species (61 FR 64481). From 1996 to 2010 (see below), the Sonoran populations of desert tortoise did not have any Federal status inside their known range (south and east of the Colorado River).

On October 15, 2008, we received a petition dated October 9, 2008, from WildEarth Guardians and Western Watersheds Project (petitioners) requesting that the Sonoran population of the desert tortoise be listed under the Act as a distinct population segment (DPS), as threatened or endangered rangewide (in the United States and Mexico), and critical habitat be designated. On August 28, 2009, we made our 90-day finding that the petition presented substantial scientific information indicating that listing the Sonoran DPS of the desert tortoise may be warranted. The finding and notice of our initiation of a status review was published in the Federal Register on August 28, 2009 (74 FR 44335). On December 14, 2010, we published our 12-month finding that listing the Sonoran DPS of the desert tortoise was warranted, but precluded by other higher priority actions, and the entity was added to our list of candidate species (75 FR 78094).

Candidate status for the Sonoran DPS of desert tortoise was reaffirmed in the 2011 Candidate Notice of Review (76 FR 66370; October 26, 2011). In 2012, new information was assessed that elevated the Sonoran populations of the desert tortoise to a full species (Gopherus morafkai). We noted this taxonomic change in the 2012 Candidate Notice of Review and revised its accepted nomenclature to “Sonoran desert tortoise” (77 FR 69994; November 21, 2012). We also reaffirmed its candidate status in the Candidate Notices of Review published in 2012 (77 FR 69994; November 21, 2012), 2013 (77 FR 70104; November 22, 2013), and 2014 (79 FR 72450; December 5, 2014).

In 2011, the Service entered into two settlement agreements regarding species on the candidate list at that time (Endangered Species Act Section 4 Deadline Litigation, No. 10-377 (EGS), MDL Docket No. 2165 (D.D.C. May 10, 2011)). This finding fulfills our obligations regarding the Sonoran desert tortoise under those settlement agreements.

We collaborated with species experts from public and private sectors to complete the Species Status Assessment Report for the Sonoran Desert Tortoise (SSA Report; Service 2015, entire), which is available online at http://www.regulations.gov, Docket No. FWS-R2-ES-2015-0150, and at https://www.fws.gov/southwest/es/Arizona. The SSA Report documents the results of the comprehensive biological status review for the Sonoran desert tortoise (tortoise) and provides an account of the species' overall viability through forecasting of the species' condition in the future (Service 2015, entire). In the SSA Report, we summarized the relevant biological data and a description of past, present, and likely future risk factors and conducted an analysis of the viability of the species. The SSA Report provides the scientific basis that informs our regulatory decision regarding whether this species should be listed as an endangered or threatened species under the Act. This decision involves the application of standards within the Act, its implementing regulations, and Service policies (see Finding below). The SSA Report contains the risk analysis on which this finding is based, and the following discussion is a summary of the results and conclusions from the SSA Report. We solicited peer review of the draft SSA Report from five qualified experts. Responses were received from four of the reviewers, and the SSA Report was modified as appropriate.

The Sonoran desert tortoise was first described by Cooper in 1863 (pp. 118-123). Since that time, the Sonoran desert tortoise was recognized as a population of the desert tortoise (Gopherus agassizii) until advanced genetic analysis supported elevating the Sonoran population of the desert tortoise as a unique species, Morafka's desert tortoise (Gopherus morafkai) (Murphy et al. 2011, p. 53). As a result, the Sonoran desert tortoise is recognized as a distinct species (G. morafkai) but retains its common name of “Sonoran desert tortoise” as recommended in Crother et al. (2012, pp. 76-77) to avoid potential confusion of the abbreviation for Morafka's desert tortoise with that of the Mojave desert tortoise (G. agassizii).

The Sonoran desert tortoise occupies portions of western, northwestern, and southern Arizona in the United States, and the northern two-thirds of the Mexican State of Sonora. In Arizona, adult Sonoran desert tortoises range in total carapace (top shell) length from 8 to 15 inches (in) (20 to 38 centimeters (cm)), with a relatively high domed shell (Arizona Game and Fish Department (AGFD) 2001, p. 1; Brennan and Holycross 2006, p. 54). The maximum recorded length for a Sonoran desert tortoise in Arizona is 19.4 in (49 cm) total carapace length (Jackson and Wilkinson-Trotter 1980, p. 430). The hind limbs are very stocky and elephantine; forelimbs are flattened for digging and covered with large conical scales (AGFD 2001, p. 1; Brennan and Holycross 2006, p. 54). Male Sonoran desert tortoises are differentiated from females by having elongated gular (throat) shields, chin glands visible on each side of the lower jaw (most evident during the breeding season), and a concave plastron (bottom shell) (AGFD 2001, p. 1).

Sonoran desert tortoises are coldblooded species, which rely on their environment to regulate body temperature (thermoregulation). They feed on a variety of vegetation and spend the majority of their time in underground shelters, coming out mainly to drink, forage, and breed. Tortoises, especially young, small tortoises, are subject to predation by a variety of natural predators, including lizards, snakes, and mammals.

In general and compared to many other animals, tortoises have relatively low fecundity (females lay about 5 eggs on average every other year), are slow-growing (they may take 15 years to reach sexual maturity), are long-lived (they may live more than 50 years in the wild), experience high survivorship in the wild, and have a relatively long generation time (25 years). The Sonoran desert tortoise's breeding season generally occurs from July through October.

The tortoise occurs primarily in rocky, steep slopes and bajadas (broad slope extending from the base of a mountain range out into a basin) in various desertscrub habitat types. Tortoise home range size varies with precipitation levels, contracting during wet years and expanding during dry years in response to the availability of forage plants (Averill-Murray and Klug 2000, p. 67). Estimates for average home range sizes for males have varied from 0.04 to 0.10 square miles (sq mi) (10 to 26 hectares (ha)); females generally have smaller home ranges, with averages ranging from 0.01 to 0.09 sq mi (2.6 to 23 ha) (Barrett 1990, p. 203; Averill-Murray and Klug 2000, pp. 55-61; Averill-Murray et al. 2002a, pp. 150-151).

We conducted a coarse geospatial analysis (see Overview of Analytical Tools) of potential habitat based on elevation, slope, and vegetation type across the species' range. We categorized the potential habitat as high, medium, or low suitability based on the presence of the habitat features that support tortoises (a combination of elevation, vegetation type, and slope). This rangewide geospatial analysis resulted in a prediction of approximately 38,000 sq mi (9.8 million ha) of potential tortoise habitat (see Map 1—Current Sonoran Desert Tortoise Predicted Potential Habitat). Of this total, 64 percent occurs in the United States, and 36 percent occurs in Mexico.

Individual tortoises need access to plants, shelters, and freestanding water. A variety of plants are used for forage, shelter for thermoregulation, and cover from predators. Access to shelter sites is also important for predator avoidance and thermoregulation. Freestanding water is needed for hydration. Finally, tortoises need enough available space to complete movements to support life-history functions of feeding and breeding. Tortoises have a specific combination of habitat needs (forage plants, cover, shelter sites, water), but those habitat needs can be found throughout a wide geographic area.

For the Sonoran desert tortoise to maintain viability over the long term, it needs populations of adequate size and distribution to support resiliency, redundancy, and representation. While we do not know the size of a viable population of Sonoran desert tortoise, populations with larger numbers of individuals have improved chances of withstanding stochastic events (a measure of resiliency). The tortoise also needs to have resilient populations spread across its range, supported by suitable habitat quantity and quality, to provide for rangewide redundancy (species ability to withstand catastrophic events such as potential large-scale drought) and representation (species genetic and ecological diversity to maintain adaptive capacity).

We used two analytical tools to synthesize and summarize our understanding of the best available information about the current and future conditions of the tortoise. These tools include a geospatial analysis of habitat and a population simulation model. Here we describe these tools conceptually to provide context for the discussions that follow. More explanation of these tools is available in the SSA Report (Service 2015, entire).

One tool we used was a coarse geospatial analysis to determine the extent of potential habitat based on elevation, slope, and vegetation type across the species' range. Potential habitat was categorized by suitability (high, medium, and low) based on presence of habitat features that support tortoises. We then categorized the potential habitat into primary, secondary, or tertiary quality categories. The categorization of habitat quality is based on the current suitability of potential habitat (high, medium, and low) and the possible presence of risk factors that could have population-level effects (see Risk Factors discussion below). The habitat quality analysis was conducted under two alternative assumptions related to the effects of the risk factors (high or low threats) and two alternative assumptions regarding the effects of conservation measures (high or low management). We were able to use the results of this geospatial analysis to estimate the amount and condition of current and future potential habitat, as well as evaluate the scope of various stressors on the landscape. It is important to note that potential habitat is categorized as high, medium, and low suitability, and habitat quality (a combination of potential habitat and risk factors) is categorized as primary, secondary, and tertiary.

Another tool we used was a population simulation model. The population model takes a given starting abundance of tortoises and calculates the future abundance over time by applying reproductive and survival rates (i.e., vital rates). These vital rates are the proportion of the total tortoises in a population that are surviving, being adding to the population through reproduction, or being removed from the population each year. By calculating the number of tortoises being added to the population through reproduction and taken away from the population through death each year, it allows us to project the change in the abundance of tortoises over time based on those vital rates.

We used a combination of geospatial analysis and population simulation modeling to project the condition of tortoise populations. The geospatial analysis predicts the amount and condition of habitats available to tortoises currently and in the future, and the population simulation model projects the abundance of tortoises that can be supported by that habitat based on rates of survival, growth, and reproduction (i.e., vital rates). The population simulation model projects higher densities of tortoises in higher quality habitat. As a result, the population simulation model projects abundance based on both the amount and condition of habitats.

The geospatial analysis and population simulation model combine to project the amount, condition, and distribution of potential habitat; and the abundance, growth rate, and quasi-extinction risk for tortoise populations. We are using the term quasi-extinction to encompass the idea that, before a species actually goes extinct, it will decline to a point where extinction will likely be inevitable as a result of genetic and ecological impacts, even though it has multiple surviving individuals. Because there is a great deal of uncertainty around where the precise quasi-extinction threshold is for each species, our population simulation model assesses a higher and lower threshold of quasi-extinction. Taking into account these and other uncertainties, results of the population simulation modeling are presented as a range in the following discussions.

Finally, in the models, areas in the United States and Mexico were treated as two separate areas of analysis because there are meaningful differences in the quality and level of information available about status and risk factors between the two areas, and because there are actual differences in habitat quality due to differences in land management between the two countries.

We reviewed the potential risk factors (i.e., threats, stressors) that could be affecting the tortoise. Owing to the relatively wide geographic range of the species, individual tortoises may be impacted by a variety of factors. However, in this document we will discuss only those factors in detail that could meaningfully impact the status of the species. Concerns about the tortoise's status revolve around six primary risk factors: (1) Altered plant communities; (2) altered fire regimes; (3) habitat conversion of native vegetation to developed landscapes; (4) habitat fragmentation; (5) human-tortoise interactions; and (6) climate change and drought.

We evaluated each of these factors in detail for their potential to have population- and species-level effects to the Sonoran desert tortoise. While many of them could be having effects on individual tortoises, most have not been shown or are not expected to have population-level effects on the species. Some factors may have population-level effects, but, because of the long lifespan, relatively high abundance, and wide range of the Sonoran desert tortoise, these effects would likely take many decades or longer to have measurable impacts on the species if they occur. In addition, many of these factors are ameliorated to some degree by ongoing conservation efforts or land management considerations; an estimated 73 percent of potential habitat in the United States has some conservation management, and 55 percent of potential habitat in the United States was included in a recent interagency conservation agreement committing Federal land managers to continuing conservation efforts for the tortoise (see Conservation Measures and Land Management).

Altered plant communities are a concern due to the presence of nonnative grasses in tortoise habitats. Nonnative grass species can compete with native grass species for space, water, and nutrients, thereby affecting native plant species density and species composition within invaded areas (Stevens and Fehmi 2008, pp. 383-384; Olsson et al. 2012a, entire; 2012b, pp. 10, 18-19; McDonald and McPherson 2011, pp. 1150, 1152; Franklin and Molina-Freaner 2010, p. 1664). This process is primarily driven by the timing and amount of precipitation. Geospatial analysis of available data indicates that about 15 percent of the current predicted suitable habitat for tortoises in Arizona and 20 percent in Mexico may have nonnative vegetation.

Presence of nonnative grasses does not preclude use of an area by tortoises, but it may impact tortoises by reducing available plants for forage and cover. Reduced access to quality native plants may cause tortoises to expend additional time and energy foraging, thereby reducing fitness and exposing them to additional predation. However, tortoises can and do utilize nonnative grasses as forage, and no studies have confirmed that the nonnative species are significantly less nutritious to tortoises. Reduction in plant cover can negatively impact thermoregulation and increase exposure to predators. A reduction in cover plants used by tortoises can limit thermoregulatory opportunities and reduce periods of potential surface activity, making individuals more susceptible to dehydration, as well as increase predation risk when the individuals are active on the surface (Gray 2012, entire).

Theoretically, the effects of nonnative grasses on individual tortoises discussed above may manifest in population-level effects if reduced fitness and increased predation resulted in population-level declines. However, such population-level effects have not been identified through long-term monitoring, despite the fact that some species of nonnative grass have occurred within monitoring plots for decades, nor have population-level effects been documented. Further, population-level effects, if they are occurring, would only become discernible (with current research and monitoring methods) over an extremely long period of time (decades to centuries) due to the life history and longevity of the species. Adequate time periods are well outside of both the existing period of monitoring and our ability to reasonably predict such population-level effects in the future.

The presence of nonnative plants has the potential to result in more severe, frequent fires in tortoise habitats than would have occurred naturally. In some conditions, wildfire can occur naturally in tortoise habitats, but fire has not historically been a significant influence in these habitats. In desertscrub communities that are free of nonnative grasses, wildfire has a long return interval and is rarely able to carry itself over a spatially significant area due to the extent of bare ground between vegetated patches. In areas invaded by nonnative grasses, the density of fine fuels increases while open space between vegetation decreases, causing changes in fire behavior and, ultimately, in the fire regime.

Altered fire regimes resulting in more severe, frequent fires may impact tortoises directly through exposure to fire and indirectly via impacts to plants used as forage and cover. Direct effects to tortoises can include fatality or injury through incineration, elevated body temperature, poisoning from smoke inhalation, and asphyxiation. Fire burns plants used for food and cover, which indirectly impacts tortoises by increasing forage effort and prolonging exposure to predators, both of which reduce fitness of individuals. The magnitude of the impact of fire on tortoises largely depends on the severity of the fire (e.g., a less severe fire may leave patches of usable forage and microhabitat for shelter and thermoregulation).

The scope of fire as a risk factor in Arizona is associated with presence of nonnatives in conjunction with ignition sources and fire suppression. Geospatial analysis suggests that fire may be a concern in 23 percent of predicted suitable habitat in Arizona. However, despite the fact that many wildfire ignitions occur annually in desertscrub communities within the range of the Sonoran desert tortoise, aggressive wildfire suppression practices are widely implemented by agencies and municipalities across the landscape in desertscrub communities. As a result of these practices, a very limited amount of tortoise habitat has burned in comparison to the total area considered potential habitat for Sonoran desert tortoises across their range. We expect that aggressive wildfire suppression practices will continue in Arizona into the future in order to protect ecological values and human health and property and, therefore, do not expect this stressor to have an appreciable effect on Sonoran desert tortoises at the population-level in Arizona.

Geospatial analysis suggests that fire may be a concern in 20 percent of predicted suitable habitat in Mexico where fire occurs more regularly to manage buffelgrass (Pennisteum cilare) pastures. Buffelgrass is a nonnative species that is cultivated more widely in Mexico to support grazing. Fires set intentionally in Mexico to benefit buffelgrass pastures could potentially affect tortoise populations. However, while these buffelgrass pasture areas are within the absolute range of the tortoise, pastures are generally found in flat valley bottoms, and tortoises generally prefer rocky slopes, thus tortoises likely have reduced exposure to fire in cultivated pastures. Additionally, the best available information does not suggest that fires to benefit buffelgrass pastures in Mexico are affecting tortoises at a magnitude or frequency that would result in population-level effects. Therefore, we do not expect this stressor will have an appreciable effect on Sonoran desert tortoises in Mexico.

Conversion of natural habitat via urban and agricultural development can have a variety of direct and indirect impacts on tortoises depending on the intensity and size of the development. Habitat conversion can directly impact tortoises via fatalities during the construction or development process. If tortoises survive the initial construction, conversion may impact tortoises by making areas entirely unusable (i.e., nonhabitat) or by removing forage and cover sites thus making the habitat less productive for tortoises. Habitat areas converted to dense urban uses likely displace animals into surrounding areas, if adjacent suitable habitat exists. Tortoises that survive the initial development, but are not entirely displaced, likely have reduced access to plants used as forage and cover and, therefore, likely have reduced fitness and are subject to additional predation. Habitat conversion may also result in fragmentation that can impact short- and long-range movements (see Habitat Fragmentation discussion below). However, population-level effects to Sonoran desert tortoises from habitat conversion have not been documented in the literature.

To assess the potential historical loss of habitat due to conversion to urban landscape, we calculated the amount of area currently designated as urban land within the range boundary of the Sonoran desert tortoise. About 1,279 sq mi (331,260 ha) of area is currently designated as urban in Arizona. If all of this urban area had previously been potential tortoise habitat, which is unlikely, this area would represent approximately 5 percent of all estimated historical habitat. In Mexico, about 53 sq mi (13,730 ha) of area is designated as urban. This represents less than 1 percent of all estimated historical habitat. Even considering additional areas potentially lost historically due to agricultural or other development (which we have not quantified due to data limitations), historical habitat loss appears to be relatively small.

Looking into the future, urban development in Arizona is expected to occur primarily within a zone referred to as the Sun Corridor Megapolitan, driven primarily by its association with major transportation routes and other existing infrastructure. In a northward direction from the U.S.-Mexico border, this development zone occurs within the range of the Sonoran desert tortoise along Interstate (I)-19, I-10, and I-17 (Gammage et al. 2008 entire; 2011 entire). Additional suburban development zones are expected to occur along I-40 near Kingman and along State Route 93, which connects Wickenburg to Kingman, especially if the latter route is converted into an interstate (proposed I-11). The majority of projected development in Arizona is not anticipated to occur in potential tortoise habitat. However, we expect as much as 9 percent of potential tortoise habitat in Arizona could be developed within the next 50-100 years. In contrast, an estimated 73 percent of potential tortoise habitat in Arizona is not likely subject to development due to land ownership and management. These areas are lands managed for a purpose not compatible with widespread development including military lands, state and municipal parks, and areas owned by Bureau of Land Management, Bureau of Reclamation, National Park Service, Forest Service, and U.S. Fish and Wildlife Service. Small areas on these land ownership types may experience development, but significant urban development in these areas is unlikely.

In Arizona, the number of acres dedicated to irrigated agriculture has been on the decline (U.S. Department of Agriculture 2009, p. 273). These areas are likely being converted into areas re-zoned for residential or commercial purposes or, rarely, left fallow for natural recovery. This observed declining trend of agricultural use will likely continue in Arizona, unless farming practices or technology change, or a novel crop significantly influences market forces and reverses this trend. Therefore, we do not anticipate appreciable future habitat conversions in Arizona due to agricultural development. Additionally, areas that may be converted to agricultural uses likely would not be preferred tortoise habitat because these uses generally occur in flat valley bottoms while tortoises prefer rocky slopes.

Within the species' range in Sonora, Mexico, and according to recent reports, urban development is also expected to continue into the future, but at a slower pace and smaller scale than Arizona. Hermosillo is the largest population center in Sonora (approximately 778,000 per the 2014 census) and could expand north and east, which could potentially affect adjacent tortoise populations (Rosen et al. 2014a, pp. 22-23). Limited urban expansion could also be predicted for a small number of other communities within Sonora (Rosen et al. 2014a, pp. 22-23). With respect to agriculture in Sonora, the majority occurs on large river deltas, which are not occupied by tortoises (Rosen et al. 2014a, pp. 22-23). Therefore, neither urban nor agricultural development is considered to be significantly affecting tortoise populations over a large area in Sonora currently, or into the future.

Habitat fragmentation via infrastructure and other forms of linear development may impact tortoises by restricting movement within and between home ranges, direct fatality, and enabling human collection. The source of habitat fragmentation is any linear feature such as roads of varying capacities, railroad tracks, and canals. These forms of linear development are largely ubiquitous across the range of the tortoise; however, the severity of the impact of linear development depends on the permeability of the feature to tortoise movement.

Tortoises move within and outside their home ranges for different purposes depending on sex, age class, and size class. Tortoises will move to find preferred plant forage species that may be in season (Oftedal 2007, entire); to a different shelter site with a different exposure, depth, or substrate (Averill-Murray and Klug 2000, p. 62); or to search for potential mates (Averill-Murray et al. 2002a, pp. 139-144). Tortoises will also move to disperse outside of their home ranges, with distances ranging from a few hundred yards to several miles or more (Edwards et al. 2004, entire). When individuals are unable to successfully complete these movements within their home ranges or on the landscape, basic natural-history functions can be compromised to varying degrees. Individual tortoises may spend more time active and exposed if they are unable to access preferred sites for forage and shelter, which may result in reduced fitness.

Fragmentation can also be a concern if it prevents movements between populations. This degree of fragmentation could impact species' representation through effects on genetic diversity, and it could impact species' redundancy if recolonization of an area extirpated by a stochastic event is precluded.

Roads can also be a source of injury, mortality, and collection. Unlike some other species, tortoises do not appear to avoid roads and are thus susceptible to impacts there. However, the severity of these kinds of impacts is likely correlated with road width, road type (e.g., rugged, improved gravel, paved), speed limits, traffic volume, availability of washes or other means of crossing under roads, and quality of tortoise habitat being transected. See “Human-Tortoise Interactions” for further discussion of these kinds of impacts.

More severe effects to tortoise individuals and populations as a result of fragmentation are possible where fragmenting features are less permeable to tortoises or where fragmenting features are more dense. For example, a multi-lane road is less permeable to tortoises than a single lane dirt road. Similarly, an area bisected by multiple roads and canals is likely to have a greater affect on tortoises because there are multiple obstacles to navigate while moving through an area. In these situations, impacts to tortoises could be more severe because there is higher potential for human interactions, and fragmentation of home ranges and populations may be more complete.

While the effects of fragmentation, as discussed above, could theoretically manifest in population-level effects, there is no evidence of such population-level effects. Population-level effects due to fragmentation would only become discernible (with current research and monitoring methods) over an extremely long period of time (decades to centuries) due to the life history and longevity of the species. Adequate time periods are well outside of both the existing period of monitoring and our ability to reasonably predict such population-level effects in the future.

Inadvertent or purposeful human interactions with tortoises can result in injury or death of tortoises. Human interactions can also result in collection of tortoises, thereby removing them from the wild population. Sources of interaction include roads, wild-urban interface zones, and general recreation areas. Human interaction can lead to either inadvertent or intentional impacts to tortoises. Inadvertent interactions can have incidental effects on tortoises that are not otherwise the intent or purpose of the activity itself. Examples of activities that could lead to human interactions with tortoises (when in occupied tortoise habitat) include the use of vehicles (Lowery et al. 2011, entire), target shooting, hunting, hiking, rock crawling, trail bike riding, rock climbing, and camping (Howland and Rorabaugh 2002, pp. 339-342; AGFD 2010, p. 9). In addition, dogs that escape captivity or are intentionally abandoned can form feral packs, which have been shown to impact individual Sonoran desert tortoises (Zylstra 2008, entire). Other forms of human interaction with tortoises are direct and intentional, such as collection of wild tortoises, release of captive tortoises into wild populations, or physically handling wild tortoises (Grandmaison and Frary 2012, entire).

These types of human interactions with tortoises occur at highest frequency in the wild-urban interface zone and are thought to lessen with increasing distance from human population centers (Zylstra et al. 2013, pp. 112-113). In fact, one study found that adult tortoise survivorship has been shown to improve with increasing distance from urbanized areas; specifically, the odds of a Sonoran desert tortoise surviving 1 year increases 13 percent for each 6.2-mile (mi) (10-kilometer (km)) increase in distance from a city of at least 2,500 people (Zylstra et al. 2013, pp. 112-113).

To assess the potential geographic scope of human interactions, we calculated the acreage of predicted potential habitat areas within 6.2-mi (10-km) rings of cities greater than 2,500 in population size. While the potential for human interactions exists beyond these areas, we assumed that the closer tortoises are to human population centers, the more likely that these interactions will occur. Overall, 29 percent of predicted potential tortoise habitat occurs within 12.4 mi (20 km) of urban areas in Arizona and 9 percent in Sonora.

While the effects of human interactions, as discussed above, could theoretically manifest in population-level effects, there is no evidence of such population-level effects. Population-level effects due to human interactions would only become discernable (with current research and monitoring methods) over an extremely long period of time (decades to centuries) due to the life history and longevity of the species. Adequate time periods are well-outside of both the existing period of monitoring and our ability to reasonably predict such population-level effects in the future.

There is unequivocal evidence that the earth's climate is warming based on observations of increases in average global air and ocean temperatures, widespread melting of glaciers and polar ice caps, and rising sea levels, with abundant evidence supporting predicted changes in temperature and precipitation in the southwestern deserts (IPCC 2014, entire). Predicted temperature trends for the region encompassing the range of the Sonoran desert tortoise include warming trends during winter and spring, lowered frequency of freezing temperatures, longer freeze-free seasons, and higher minimum temperatures during the winters (Weiss and Overpeck 2005, p. 2075). In this same region, predictions of potential changes in precipitation due to climate change are less certain, but climate scientists largely agree that annual precipitation totals are likely to decrease as compared to historical averages (Seager et al. 2007, entire; Cook et al. 2015, p. 4). Climate models generally agree that winter and spring precipitation may be influenced by climate change, with predicted decreases in precipitation during these seasons. However, modeling results vary considerably with respect to how climate change could affect summer (monsoon) precipitation in Arizona and northern Mexico. While annual precipitation totals are predicted to decrease, summer precipitation totals may increase (IPCC 2007, p. 20), with wide fluctuation in scope and severity of summer precipitation events.

Climate change may impact Sonoran desert tortoises, primarily through impacts on drought severity and duration as a result of increased air temperature and reduced precipitation. Increased drought severity and duration may impact tortoise access to freestanding water for drinking and plants for forage and cover. Climate change is predicted to reduce precipitation in the southwest and, therefore, has potential to reduce availability of freestanding water. Reduced precipitation could also reduce abundance of plants available for forage and cover, thereby increasing energy expenditures while finding forage, impairing thermoregulation, and exposing tortoises to predators. All of this can result in reduced fitness and rates of reproduction and survival. Sonoran desert tortoises evolved in a desert ecosystem and have adaptations to withstand drought; however, long-term climate change may stress tortoises beyond those tolerances.

One study has shown a measurable effect to tortoise populations due to drought. Zylstra et al. (2013, pp. 113-114) showed that, in tortoise populations that experience localized, prolonged drought conditions, annual adult survival can decrease by 10-20 percent, and abundance of adults can be reduced by as much as 50 percent or more in local instances. However, when drought conditions affecting these populations subsided, Sonoran desert tortoise numbers began to increase, reaching near pre-drought status, and the overall rate of change in population size was found to be greater than 1, indicating overall positive population growth in the populations monitored for a period of more than 20 years (Zylstra et al. 2013, pp. 112-114).

We anticipate that climate change is likely to have population-level impacts to Sonoran desert tortoises to some degree in the future. However, the severity, scope, and timing of those impacts are unknown because the intensity of the environmental changes is unknown and the response at the species level is unknown. In particular, output from climate change models exhibits noticeably increasing confidence intervals, and therefore increased uncertainty, beyond the 50- to 75-year timeframe (Seager et al. 2007, p. 1182). Based on the best available information, we cannot predict the magnitude of environmental change or the severity of the species' response over time with a reasonable degree of certainty. However, due to the potential for climate change to affect tortoises, we carefully analyzed this risk factor to the best of our ability in our population model (see Future Condition and Viability below).

It is possible that several risk factors may be impacting Sonoran desert tortoise populations cumulatively now and into the future. Theoretically, for every additional risk factor occurring in a population area, the likelihood of population-level impacts increases. However, no areas are currently known to be in decline due to individual or cumulative impacts, including impacts from potential stressors that were not discussed in detail in this document, and just as with assessment of the individual risk factors, the theoretical population-level effects due to cumulative impacts at current and predicted levels would only become discernible (with current research and monitoring methods) over an extremely long period of time (decades to centuries) due to the life history and longevity of the species. Adequate time periods are well outside of both the existing period of monitoring and our ability to reasonably predict such population-level effects in the future.

There are a number of conservation actions that have been implemented to minimize stressors and maintain or improve the status of the Sonoran desert tortoise, including a candidate conservation agreement (AIDTT 2015, entire) with AGFD, Bureau of Land Management, Department of Defense, National Park Service, U.S. Fish and Wildlife Service, Bureau of Reclamation, Customs and Border Protection, U.S. Forest Service, Natural Resources Conservation Service, and Arizona Department of Transportation (collectively referred to as “Parties”). Candidate conservation agreements are formal, voluntary agreements between the Service and one or more parties to address the conservation needs of one or more candidate species or species likely to become candidates in the near future. Participants voluntarily commit to implement specific actions designed to remove or reduce stressors to the covered species, so that listing may not be necessary. The agreement for the Sonoran desert tortoise, which formalizes many existing conservation measures and land management practices, was completed by the Parties in March 2015 and was signed by the final signatory, the Service, on June 19, 2015. The agreement applies to approximately 13,000 sq mi (3.4 million ha) of Sonoran desert tortoise habitat in Arizona. This area represents approximately 55 percent of the species' predicted potential habitat in Arizona and 34 percent of its predicted potential habitat rangewide.

The agreement is designed to encourage, facilitate, and direct effective tortoise conservation actions across multiple agencies and entities having the potential to directly influence conservation of the species in Arizona. Parties to the agreement identified existing tortoise conservation measures and designed a comprehensive conservation framework for these measures that encourages coordinated actions and uniform reporting, integrates monitoring and research efforts with management, and supports ongoing conservation partnership formation. Management actions in the agreement include, but are not limited to, reducing the spread of nonnative grasses, reducing or mitigating dispersal barriers, reducing the risk and impact of desert wildfires, reducing the impact of off-highway vehicles, population monitoring, and reducing illegal collection of tortoises. A complete list of the stressor-specific conservation measures can be found in Appendix A of the CCA (AIDTT 2015).

Additionally, as discussed above, an estimated 73 percent of potential tortoise habitat in Arizona is not likely subject to development due to land ownership and management. These areas are lands managed for a purpose not compatible with widespread development including military lands, state and municipal parks, and areas owned by Bureau of Land Management, Bureau of Reclamation, National Park Service, Forest Service, and U.S. Fish and Wildlife Service. Small areas on these land ownership types may experience development, but significant development on these lands is unlikely.

Generally, the best available scientific information suggests that the Sonoran desert tortoise has not experienced any appreciable reduction in its overall range or abundance relative to presumed historical levels. Certainly some areas of former habitat have been lost due to conversion to urban and agricultural uses, but our geospatial analysis suggests that the magnitude of these loses is relatively minimal (see “Habitat Conversion” discussion above). This suggests that the species has potential to retain historical levels of resiliency, redundancy, and representation (and, therefore, viability) if the habitat condition now and into the future is in acceptable condition relative to risk factors.

As discussed above, we conducted a coarse geospatial analysis of potential habitat based on elevation, slope, and vegetation type across the species' range. This rangewide geospatial analysis resulted in a prediction of approximately 38,000 sq mi (9.8 million ha) of potential tortoise habitat. We then evaluated the current condition (status) of the tortoise by categorizing habitat into primary, secondary, or tertiary quality categories. The categorization of habitat is based on the current suitability of potential habitat (high, medium, and low) and the possible presence of risk factors that could have population-level effects. We used four geospatial layers to measure those risk factors: Land management, presence of nonnative vegetation, high fire risk potential, and proximity to urban areas. The habitat quality analysis was conducted under two alternative assumptions related to the effects of the risk factors (high or low threats) and two alternative assumptions regarding the effects of conservation measures (high or low management).

For the U.S. analysis area, this geospatial analysis resulted in 8 to 25 percent of potential tortoise habitat being categorized primary quality, 62 to 75 percent categorized as secondary quality, and 13 to 17 percent categorized as tertiary quality (see Table 1—Modeled Current Habitat Quality-Arizona). In Mexico, this analysis resulted in 0 to 2 percent of potential habitat being categorized as primary quality, 79 to 98 percent categorized as secondary quality, and 0.2 to 21 percent categorized as tertiary quality (see Table 2—Modeled Current Habitat Quality-Mexico). The amount in each category is presented as a range due to the four alternative assumptions related to the effects of risk factors and effects of conservation measures.

Executive Summary

Why we need to publish a rule. Under the Act, if we determine that a species is an endangered or threatened species throughout all or a significant portion of its range, we are required to promptly publish a proposal in the Federal Register and make a determination on our proposal within 1 year. Critical habitat shall be designated, to the maximum extent prudent and determinable, for any species determined to be an endangered or threatened species under the Act. Listing a species as an endangered or threatened species and designations of critical habitat can only be completed by issuing a rule.

This rule proposes the listing of the Suwannee moccasinshell (Medionidus walkeri) as a threatened species. The Suwannee moccasinshell is a candidate species for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing regulation has been precluded by other higher priority listing activities. This rule reassesses all available information regarding status of and threats to the Suwannee moccasinshell.

This rule does not propose critical habitat for the Suwannee moccasinshell. We have determined that designation of critical habitat is prudent, but not determinable at this time because:

• While we have significant information on the habitat of the species, we need more information on biological needs of the species (i.e., specific habitat features on the landscape) in order to identify specific areas appropriate for critical habitat designation.

• In addition, as we have not determined the areas that may qualify for designation, the information sufficient to perform a required analysis of the impacts of the designation is lacking.

The basis for our action. Under the Act, we may determine that a species is an endangered or threatened species based on any of 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. We have determined that this species is threatened by degradation of its habitat due to polluted runoff from agricultural lands, discharges from industrial and municipal wastewater sources and mining operations, sedimentation, decreased flows due to groundwater extraction and drought (Factor A); State and Federal water quality standards that are inadequate to protect sensitive aquatic organisms like mussels (Factor D); contaminant spills as a result of transportation accidents or from industrial, agricultural, and municipal facilities (Factor E); increased drought frequency as a result of changing climatic conditions (Factor E); greater vulnerability to certain threats because of small population size and range (Factor E); and competition and disturbance from the introduced Asian clam (Factor E).

We will seek peer review. We will seek comments from independent specialists to ensure that our designation is based on scientifically sound data, assumptions, and analyses. We will invite these peer reviewers to comment on our listing proposal.

Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal.

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

(1) The Suwannee moccasinshell's biology, range, and population trends, including:

(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range including distribution patterns;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, its habitat, or both.

(2) Factors that may affect the continued existence of the species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.

(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species and existing regulations that may be addressing those threats. In particular, we seek information concerning the potential threats to the Suwannee moccasinshell, including:

(a) The effects of pesticides and their ingredients and metabolites on the species;

(b) The impact of diseases on the species;

(c) The impact of flood scour on the species and its habitat; and

(d) The impact of introduced flathead catfish on fishes needed by the species to reproduce.

(4) Additional information concerning the historical and current status, range, distribution, and population size of this species, including the locations of any additional populations of this species.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

Please note that 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, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is a threatened or endangered species must be made “solely on the basis of the best scientific and commercial data available.”

You may submit your comments and materials concerning this proposed rule by one of the methods listed in ADDRESSES. We request that you send comments only by the methods described in ADDRESSES.

If you submit information via http://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy 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 hardcopy submissions on http://www.regulations.gov.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Panama City Ecological Services Office (see FOR FURTHER INFORMATION CONTACT).

Section 4(b)(5) of the Act provides for one or more public hearings on this proposal, if requested. Requests must be received within 45 days after the date of publication of this proposed rule in the Federal Register. Such requests must be sent to the address shown in FOR FURTHER INFORMATION CONTACT. We will schedule public hearings on this proposal, if any are requested, and announce the dates, times, and places of those hearings, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing.

In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), we are seeking the expert opinions of three appropriate and independent specialists regarding this proposed rule. The purpose of peer review is to ensure that our listing determination is based on scientifically sound data, assumptions, and analyses. The peer reviewers have expertise in Suwannee moccasinshell biology, habitat, physical or biological factors, etc., and are currently reviewing the species status report, which will inform our determination. We invite comment from the peer reviewers during this public comment period.

We identified the Suwannee moccasinshell (Medionidus walkeri) as a Category 2 species in the Candidate Notice of Review (CNOR) published in the Federal Register of November 15, 1994 (59 FR 58982). Category 2 candidates were defined as species for which we had information that proposed listing was possibly appropriate, but for which conclusive data on biological vulnerability and threats were not available to support a proposed rule at the time. In the February 28, 1996, CNOR (61 FR 7596), we discontinued the designation of Category 2 species as candidates; therefore, the Suwannee moccasinshell was no longer a candidate species.

In 2010, the Center for Biological Diversity (CBD) petitioned the Service to list 404 aquatic, riparian, and wetland species from the southeastern United States under the Act. On September 27, 2011, the Service published a substantial 90-day finding for 374 of the 404 species, including the Suwannee moccasinshell, soliciting information about, and initiating status reviews for, those species (76 FR 59836). In 2013, CBD filed a complaint against the Service for failure to complete a 12-month finding for the Suwannee moccasinshell within the statutory timeframe. In 2014, the Service entered into a settlement agreement with CBD to address the complaint; the court-approved settlement agreement specified that a 12-month finding for the Suwannee moccasinshell would be delivered to the Federal Register by September 30, 2015.

The Suwannee moccasinshell (Medionidus walkeri) is a freshwater mussel of the family Unionidae. The species was originally described by B.H. Wright in 1897; it was briefly considered a synonym of Medionidus penicillatus (Clench and Turner 1956), but subsequently was recognized as a valid species by Johnson (1977, p. 176). Its distinctiveness as a separate species is recognized by recent authors (Williams and Butler 1994, p. 85; Williams et al. 2014, p. 278). Its sharp posterior ridge and generally dark, rayless shell distinguishes it from other species of Medionidus in Gulf drainages (Johnson 1977, p. 177; Williams and Butler 1994, p. 86).

The Suwannee moccasinshell is a small mussel that rarely exceeds 50 millimeters (2.0 inches) in length. Its shell is oval in shape and sculptured with corrugations extending along the posterior ridge, although the corrugations are sometimes faint. The shell exterior (periostracum) is greenish yellow to brown with green rays of varying width and intensity in young individuals, and olive brown to brownish black with rays often obscured in mature individuals (Williams et al. 2014, p. 278). The sexes can be distinguished, with female shells being smaller and longer than the males (Johnson 1977, p. 177). The Suwannee moccasinshell is easily distinguished from all other mussels in the Suwannee River Basin by having an oval outline and sculpture on the posterior slope (Williams et al. 2014, p. 279).

Under the Act, the term “species” includes any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature (16 U.S.C. 1532(16)). Based on our review of the best available scientific and commercial information (see Taxonomy and Species Description above) the taxonomic entity that is known as Suwannee moccasinshell (Medionidus walkeri) is a distinct species. Therefore, we conclude that the Suwannee moccasinshell does meet the definition of a species under section 3(16) of the Act, and that the petitioned entity does constitute a listable entity and can be listed under the Act.

Unionid mussels live in the bottom substrates of streams and lakes where they generally burrow completely into the substrate and orient themselves near the substrate surface to take in food and oxygen. The Suwannee moccasinshell typically inhabits larger streams where it is found in substrates of muddy sand or sand with some gravel, and in areas with slow to moderate current (Williams and Butler 1994, p. 86; Williams 2015, p. 2). Recent surveys by the Florida Fish and Wildlife Conservation Commission (FFWCC) for the species in the Suwannee River main channel found individuals at depths ranging from around 0.5 to 2.5 meters (1.6 to 8.2 ft) (FFWCC 2014 unpub. data). Based on stream conditions in areas that still support the species, suitable Suwannee moccasinshell habitat appears to be clear stream reaches along bank margins with a moderate slope and stable sand substrates, where flow is moderate and slightly depositional conditions exist. These are ideal habitat conditions for most mussels in the main channel, and several species occur in areas where the Suwannee moccasinshell is found. In addition, the Suwannee moccasinshell is associated with large woody material, and individuals are often found near embedded logs. These attributes also likely indicate the habitat preferences of its host fishes.

Adult mussels obtain food items both from the water column and from the sediments. They filter feed by taking water in through the incurrent siphon and across four gills that are specialized for respiration and food collection. They can also move sediment material into the shell by using cilia (hair-like structures) on the foot or through currents created by cilia. Juvenile mussels typically burrow completely beneath the substrate surface for the first several months of their life. During this time, they feed primarily with their ciliated foot, which they sweep through the sediment to extract material, until the structures for filter feeding are more fully developed. Mussels feed on a variety of microscopic food particles that include algae, diatoms, bacteria, and fine detritus (disintegrated organic debris) (McMahon and Bogan 2001, p. 331; Strayer et al. 2004, pp. 430-431, Vaughn et al. 2008, p. 410).

Spawning in freshwater mussels general occurs from spring to late summer (Haag 2012, p. 38). Water temperature appears to be the primary cue for spawning (McMahon and Bogan 2001, p. 343; Galbraith and Vaughn 2009, p. 42). During spawning, males release sperm into the water column, which females take in through their inhalant aperture during feeding. Fertilization takes place inside the gills, and females brood the fertilized eggs in modified portions of one or both pairs of gills until they develop into mature larvae called glochidia. The timing and duration of the brooding period varies by species, but can be classified as either short term or long term. In short-term brooders, glochidia are released as soon as they are mature, generally 2-6 weeks after fertilization. In long-term brooders, the mature glochidia are brooded over the winter and released the following spring or summer.

Reproduction in unionid mussels is remarkable in that the glochidia of most species must attach to a fish host in order to transform into a juvenile mussel. Many mussel species use only one or a few specific fish species as hosts, and have evolved lures to attract a particular fish species or group of related fish species (Haag 2012, p. 42). Females of some mussel species release their glochidia, either individually (sometimes in mucus strands for suspension), in packets termed conglutinates, which resemble fish food items, or in one large mass known as a superconglutinate, which resembles a small fish (Barnhart et al. 2008, pp. 374-379). In other species, female mussels transmit glochidia directly to the host fish by using mantel flap lures to entice an attack (Barnhart et al. 2008, p. 380) and expel glochidia into the host's mouth.

The number of glochidia released by a female in one reproductive cycle can range from several thousand to several million and is extremely variable among species (Haag 2012, p. 196). The variation is related to body size with larger females producing more eggs than smaller individuals (Haag 2012, pp. 200-206). If the glochidia encounter a fish, they attempt to clamp onto the gills, fins, or skin. Glochidia that attach to a suitable host encyst in the tissues and undergo a metamorphosis. The duration of the encystment varies by mussel species, usually lasting from 2-4 weeks, but can last for several months (Haag 2012, p. 42). When the metamorphosis is complete, the juveniles drop from the host and sink to the bottom to begin life as a free-living mussel.

Parasitism primarily serves as a means of upstream dispersal for this relatively sedentary group of organisms (Haag 2012, p. 145). The intimate relationship between freshwater mussels and their host fish plays a major role in mussel distributions on both a landscape and community scale. Haag and Warren (1998, p. 304) determined that mussel community composition was more a function of fish community pattern variability than of microhabitat variability, and that the type of strategy used by mussels for infecting host fishes was the determining factor.

An ongoing study has provided preliminary information about the reproductive biology of the Suwannee moccasinshell. Females were found gravid with mature glochidia from December to February, and also in late May/early June (Johnson 2015 unpub. data). In laboratory trials, Suwannee moccasinshell glochidia transformed primarily on the blackbanded darter (Percina nigrofasciata) and to a lesser extent on the brown darter (Etheostoma edwini) (Johnson 2015 unpub. data). Six other fish species from 5 families were also tested but none transformed moccasinshell larvae. This indicates that the Suwannee moccasinshell is a host specialist and dependent on darters for reproduction, and is consistent with other members of the genus Medionidus, which also use only darters (Percidae) as hosts (Haag and Warren 2003, p. 82; Fritts and Bringolf 2014, p. 54). To attract its darter host, the moccasinshell uses a small mantel lure consisting of a vibrant blue patch on the mantel interior that it flashes while wiggling papillae on the mantel margin (Johnson 2015 unpub. data). Darters are small, bottom-dwelling fish that generally do not move considerable distances (Freeman 1995, pp. 363-365; Holt 2013, p. 657). Thus, the exclusive use of darters as a host may limit the Suwannee moccasinshell's ability to disperse, and to recolonize some areas from which it has become extirpated.

The Suwannee moccasinshell is endemic to the Suwannee River Basin in Florida and Georgia. The Suwannee River Basin is a unique river system, characterized by blackwater streams in its headwaters and numerous springs (over 300) in its middle and lower reaches. The river originates in the Okefenokee Swamp and meanders more than 400 kilometers through south-central Georgia and north-central Florida before emptying into the Gulf of Mexico. There are three large tributaries to the Suwannee River—the Alapaha, Withlacoochee, and Santa Fe Rivers. The Suwannee moccasinshell's historical range includes the lower and middle Suwannee River proper, the Santa Fe River sub-basin, and the lower reach of the Withlacoochee River (Williams 2015, p. 7). There are no freshwater mussels in the upper Suwannee River Basin (upstream of the mouth of Swift Creek) due to naturally low pH and nutrient levels (Williams et al. 2014, p. 62). Within the Suwannee River mainstem, the species is historically known from the mouth of Manatee Springs run, upstream to the vicinity of the junction of the Withlacoochee River. Within the Santa Fe sub-basin, the species is known from several locations in the Santa Fe River, one location in the New River (a headwater tributary), and one location in a small unnamed tributary to the New River. In the Withlacoochee River, it is known from three historical locations in the lower reach of the river.

There is a single record of the species from the Hillsborough River Basin, a small river basin in Florida that empties into Tampa Bay, collected by van Hyning in 1932 (Williams et al. 2014, p. 280). However, recent information obtained while examining specimens in the collection of the University of Michigan's Museum of Zoology calls the record into question. There is a possibility that the specimen, along with at least two other species, were actually collected from the Suwannee River and mislabeled (Williams 2015a in litt.). Incorrect locality data seems plausible considering that none of the three species have been found in the basin before or since the van Hyning collection (Williams 2015, p. 3; Williams 2015a in litt.). Therefore, the Hillsborough River is not considered part of the Suwannee moccasinshell's range at this time, and further research is under way that may clarify this situation.

The Suwannee moccasinshell's range has declined in recent decades, and it is presently known only from the Suwannee River main channel and the lower Santa Fe River in Florida. Recent occurrence is based on collections made from 2000 to 2015. Within the Suwannee mainstem, the moccasinshell occurs intermittently throughout a 75-mile (121-kilometer) reach of the lower and middle river from river mile (RM) 50 in Dixie/Gilchrist Counties, upstream to RM 125, near the Withlacoochee River mouth. A shell fragment was collected in 2015 approximately 7 miles downstream of the mouth of Manatee Springs run (Williams 2015b in litt.). The fragment was estimated to be several years old, and additional survey work is needed; however, if the species is found to occur in this area, its distribution would be extended downstream by several miles. Within the Santa Fe sub-basin, the species is currently known from four localities (two are shell material only) in a 28-mile segment of the lower Santa Fe River downstream of the rise. The Santa Fe River runs underground for about 5 miles and “rises” back to the surface in Alachua County. The species was not detected in recent surveys in the Withlacoochee River or in the upper Santa Fe sub-basin (upstream of the rise), which includes its tributary, the New River. The species has not been collected in the past 50 years in the Withlacoochee River; however, the lower reach of the river continues to support good mussel diversity (Williams 2015, p. 3), and additional survey work is needed to verify if it is extirpated in this sub-basin.

Targeted surveys by FFWCC biologists in 2013 and 2014 show that Suwannee moccasinshell numbers are low. Experienced mussel biologists surveyed 96 sites, covering most of its historical range, and collected a total of 67 live individuals at 21 sites, all from the Suwannee River main channel. Fourteen individuals were collected at one location, but at most sites 3 or fewer individuals were found (FFWCC 2014 unpub. data). At locations where the species was detected, it comprised only 1 percent of the mussel sample. In April of 2015, FFWCC biologists surveyed 14 sites in the lower Santa Fe River, and encountered only 1 Suwannee moccasinshell out of 1,880 mussels collected during the survey (Holcomb 2015 in litt.). A summary of occurrence, distribution, and abundance of Suwannee moccasinshell populations by waterbody are shown in Table 1 below.

Historical mussel collection data are often limited, making it difficult to compare trends in abundance over time. Available historical collection data seem to indicate that the species was more abundant at one time as several museum lots contain 20 or more individuals. However, it is difficult to compare historical collections to recent collections, as survey efforts for these collections (and for most early mussel collections) are unknown, and sometimes museum lots are split or combined. It does seem clear from museum collections that Suwannee moccasinshell numbers in the Santa Fe River sub-basin have declined dramatically in recent decades. Three lots in the Florida Museum of Natural History (4,133; 4,159; 4,160) collected from the Santa Fe River in 1934 contain a total of 70 individuals. In comparison, only two live moccasinshells have been collected in the entire Santa Fe River sub-basin since 2000 (one in 2012 and another in 2015) despite considerable survey effort in areas where the species historically occurred.

In summary, an evaluation of historical and recent collection data show the Suwannee moccasinshell has undergone a reduction in range, and may no longer persist at several locations where it historically occurred. The species may be extirpated from the Withlacoochee River, and its range and abundance have clearly declined in the Santa Fe River system, where it is now found only in the lower portion of the Santa Fe River mainstem in exceedingly low abundance. In addition, the species may not be able to reestablish populations in some areas due to its limited ability to disperse. The Suwannee moccasinshell continues to occur throughout most of its known range in the Suwannee River mainstem; however, its numbers are likely lower now than a few decades ago. Despite its low abundance, populations in the Suwannee River mainstem presently appear to be stable. We attribute its persistence in this reach to the stability of the streambed and habitat due to the prevalence of geomorphically stable limestone in the channel, and to the absence of excessive sedimentation. Also, certain threats such as contaminants and reduced flows are likely attenuated in the mainstem due to the larger volume of water (threats are discussed in detail in the following section).

Section 4 of the Endangered Species Act (16 U.S.C. 1533) (ESA, Act) and its implementing regulations (50 CFR 424) set forth procedures for adding species to the Federal List of Endangered and Threatened Wildlife. Under section 4(a)(1) of the Act, we may determine that a species is 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.

In making this finding, information pertaining to the Suwannee moccasinshell in relation to the five factors provided in section 4(a)(1) of the Act is discussed below. In considering what factors might constitute threats to this species, we must look beyond the exposure of the species to a particular factor to evaluate whether the species may respond to that factor in a way that causes actual impacts to the species. If there is exposure to a factor and the species responds negatively, the factor may be a threat and, during the status review, we attempt to determine how significant a threat it is. The threat is significant if it drives, or contributes to, the risk of extinction of the species so that the species warrants listing as an endangered or threatened species as those terms are defined in the Act. However, the identification of factors that could impact a species negatively may not be sufficient to compel a finding that the species warrants listing. The information must include evidence sufficient to suggest that these factors are threats that operate on the species to the point that the species may meet the definition of an endangered or threatened species under the Act.

The stream habitats of freshwater mussels are vulnerable to degradation and modification from a number of threats associated with modern civilization. Within the Suwannee River Basin, a rapidly growing human population and changing land use represent significant threats to the aquatic ecosystem, primarily through pollution and water withdrawal (Katz and Raabe 2005, p. 14). The Suwannee moccasinshell's habitat is subject to degradation as a result of polluted runoff from croplands and poultry and dairy operations, discharges from industries, mines, and sewage treatment facilities, and from decreased flows due to groundwater extraction (pumping) (Williams 2015, pp. 7-10). Based on our current knowledge of the Suwannee moccasinshell and related mussel species, the habitat characteristics needed to sustain healthy populations generally include (1) stable stream channels and banks; (2) stable bottom substrates that are free of excessive algae growth; (3) flows that are adequate to maintain benthic habitats, provide food and oxygen, transport sperm, and remove wastes; (4) good water quality including normal temperature, conductivity, and pH ranges, and adequate oxygen content; and (5) an environment free of toxic levels of pollutants.

Water quality in the basin has been impaired due to a number of point and nonpoint sources of pollutants. As a group, mussels are more sensitive to pollution than many other aquatic organisms, and are one of the first species to respond to water quality impacts (Haag 2012, p. 355). Descriptions of localized mortality resulting from chemical spills and other discrete point source discharges have been reported. However, rangewide decreases in mussel density and diversity may result from the more damaging effects of chronic, low-level contamination (Newton 2003, p. 2,543; Newton et al. 2003, p. 2,554). There is no specific information on the sensitivity of the Suwannee moccasinshell to common agricultural, municipal, and industrial pollutants. A multitude of bioassays conducted on other mussels show that freshwater mussels, especially in early life stages, are more sensitive than previously known to some pollutants including chlorine, ammonia, copper, nickel, fungicides, and surfactants used in pesticides and household products (Keller and Zam 1991, p. 542; Jacobson et al. 1993, pp. 879-883; Jacobson et al. 1997, pp. 2,387-2,389; Augspurger et al. 2003, pp. 2,571-2,574; Wang et al. 2007, pp. 2,039-2,046; Gibson 2015, pp. 90-91).

Ammonia poses a serious threat to mussels due to its ubiquity in aquatic systems and its high toxicity to aquatic organisms. It originates primarily from agricultural sources (from fertilizers, which are often applied as ammonia and animal wastes), but also from municipal and industrial wastewater, and atmospheric deposition. Although ammonia may be taken up by plants or converted to less toxic nitrates by naturally occurring nitrifying bacteria, nitrates also have harmful effects on juvenile and adult mussels and may act as endocrine disrupters (Bauer 1988, p. 244; Patzner and Muller 2001, pp. 330-333; Pelley 2003, p. 162; Camargo and Alonso 2006, pp. 831-849). Moreover, ammonia may occur in sediments at greater concentrations than the water column (Frazier et al. 1996, pp. 92-99); such occurrences may go undetected by common water quality monitoring methods, but may have lethal or sublethal effects on mussels (Augspurger et al. 2003, pp. 2,571-2,574; Wang et al. 2007, pp. 2,039-2046), which burrow and feed (with their foot) in sediments. The Environmental Protection Agency (EPA) recently revised its water quality standards to levels considered protective of freshwater mollusks, but it will be several years before facilities must comply with the new limits (see discussion under Factor D).

Pesticides are other widespread contaminants that have long been implicated in mussel declines. Pesticides have been linked to freshwater mussel die-offs (Fleming et al. 1995, pp. 877-879), and lab studies show that mussel glochidia and juveniles are particularly sensitive to common pesticides (Conners and Black 2004, pp. 362-371; Bringolf et al. 2007a, pp. 2,089-2,093). A surfactant (MON 0818) used in the common herbicide Roundup® was found to be severely toxic to juvenile mussels and glochidia (Bringolf et al. 2007b, pp. 2,096-2,097). The potential role of pesticides in mussel declines has received more attention in recent years, but the full range of long-term effects of pesticides, and their ingredients and metabolites, remain unknown (Haag 2012, pp. 374-379).

An emerging category of contaminant threats to aquatic species is pharmaceuticals, including birth control drugs, antidepressants, and livestock growth hormones originating from municipal, agricultural, and industrial wastewater sources. These chemicals may act as endocrine disrupters and can affect mussel reproduction in a number of ways, including causing feminization of male mussels (Gagne et al. 2001, pp. 260-268; Gagne et al. 2011, pp. 99-106).

High levels of nutrients such as nitrogen and phosphorus may indirectly impact mussels by stimulating algae growth. In excess, these nutrients lead to algal blooms, which deplete oxygen and can also cause dense mats of filamentous algae to form that can entrain juvenile mussels (Hartfield and Hartfield 1996, p. 373). Juveniles may be particularly sensitive to hypoxic (oxygen-deprived) and eutrophic (nutrient-rich) conditions since they inhabit interstitial spaces in stream substrates rather than the sediment surfaces occupied by adults (Sparks and Strayer 1998, pp. 132-133).

As discussed under Factor D below, State and Federal regulatory mechanisms have helped to reduce the negative effects of point source discharges since the 1970s, yet discharges continue to impact water quality in the Suwannee River Basin. There are 246 National Pollutant Discharge Elimination System (NPDES) permitted facilities within the basin; most of them discharge into streams that ultimately flow into the middle and lower Suwannee River main channel where the majority of the moccasinshell population occurs. According to 2014 monitoring data, the top pollutants discharged into the Suwannee River Basin by weight were (in decreasing order of value) total suspended solids, nitrogen, phosphorus, fluoride, and ammonia (EPA 2014). Additionally, the toxic-weighted pound equivalent (TWPE), used to compare the potential toxic nature of one pollutant to another, indicates that the most hazardous pollutants discharged into the Suwannee River Basin are (in decreasing order of toxicity) toxaphene (a pesticide), fluoride, chlorine, iron, and ammonia (EPA 2014). In previous years, top toxicants discharged into the basin also included copper and cyanide.

Facilities permitted to discharge substantial amounts of wastewater into areas that may affect Suwannee moccasinshell populations include the Valdosta wastewater treatment plant (WWTP), which is permitted to discharge 12 million gallons per day (mgd) to the Withlacoochee River in Lowndes County, GA; Packaging Corp. of America, which is permitted to discharge 55 mgd to the Withlacoochee River in Lowndes County, GA; PCS Phosphate Company, Inc., which is permitted to discharge 200 mgd to creeks that flow to the Suwannee River in Hamilton County, FL; Florida Power Corp., which is permitted to discharge 342 mgd to the Suwannee River in Suwannee County, FL; and Pilgrim's Pride Poultry Processing Facility, which is permitted to discharge 1.5 mgd to the Suwannee River in Suwannee County, FL (EPA 2014).

Pollutants released by these facilities in 2014, and considered significant (either because of the amount or potential to affect mussels) include total suspended solids, nitrogen, phosphorus, ammonia, fluoride, iron, and copper (EPA 2014). In addition, spills of municipal wastewater at the treatment plant in Valdosta, GA, have leaked untreated sewage into the Withlacoochee River on multiple occasions. This facility has been a source of periodic releases of millions of gallons of untreated sewage, the most recent occurring in the summer of 2013 (Williams 2015, p. 8). This issue is currently being addressed by the City of Valdosta, which is making numerous improvements, including a new WWTP, which is scheduled for completion in 2016. PCS Phosphate Company, Inc., is a large phosphate strip mining and fertilizer manufacturing operation near White Springs, FL. The facility is currently permitted to discharge effluent into creeks that flow to the Suwannee River, but surface runoff and periodic overflow of settling ponds as a result of heavy rain events may have resulted in inputs of total suspended solids, phosphorus, and ammonia into the river (Williams 2015, p. 8).

Nonpoint source pollution is another significant threat throughout the Suwannee Basin, entering the system by surface runoff or through groundwater. Nonpoint source impacts are attributable primarily to the conversion of forests and wetlands to agricultural lands; agriculture accounts for most of the developed land uses within the basin, and includes silviculture, row crops, and pasture (Katz and Raabe 2005, p. 9). Surface runoff from these lands may transport numerous pollutants including pesticides, fertilizers, metals, sediments, and pathogens into stream channels. Surface drainage is more prevalent in the upper two-thirds of the basin and the upper Santa Fe River sub-basin where the soils are resistant to infiltration (Katz and Raabe 2005, p. 5).

Pollutants can also enter stream channels via groundwater inflow. The Suwannee River Basin has the highest density of springs globally (FDEP 2003, p. 29). The majority of flow in the middle Suwannee River Basin originates from groundwater sources, as the region is highly connected to the underlying Floridan aquifer (FDEP 1985, p. iv). This is evidenced by the relative lack of surface water bodies in the middle Suwannee River Basin since most water flows through the overlying karst features and directly into the aquifer (FDEP 2003, p. 27). For these reasons, the middle and lower portions of the Basin are particularly vulnerable to groundwater contamination. Katz et al. (1999, pp. 49-50) observed groundwater nitrate levels that were seven times greater than background levels in areas dominated by cropland, and estimate that it may take several decades for nitrogen concentrations to return to their original state. Additionally, all nine springs in the basin monitored by the Florida Department of Environmental Protection (FDEP) from 2012-2013 exceeded the nitrate criterion for spring vents (FDEP 2014a, p. 228), suggesting that contamination is persistent and widespread in the central and lower Suwannee River Basin.

Trends suggest that certain nonpoint source pollutants are becoming more abundant in the Suwannee River Basin. According to FDEP (2003, pp. 76, 83) nitrates are by far the biggest water quality concern in the middle and lower portions of the Suwannee Basin. Total estimated nitrogen increased continuously from 1955 to 1997 in Gilchrist and Lafayette counties (Katz et al. 1999, pp. 45-48). Nitrates have been monitored at the U.S. Geological Survey (USGS) monitoring site at Branford, FL, since 1954 and the overall trend is increasing (Thom et al. 2015, p. 100). Of seven Florida surface water quality stations monitored by FDEP in the basin during 1999-2012, increases in total nitrogen were observed at four sites, levels of algae and nitrates increased at three sites, and phosphorus and fecal coliform increased at two sites (FDEP 2014a, pp. 106-123). Nitrogen levels in the Suwannee River Basin have likely increased due to nonpoint sources such as runoff from croplands, dairy farms, and poultry facilities (Katz et al. 1999, p. 49). Fertilizer use in the area probably peaked in the late 1970s (FDEP 2008, pp. 95-100), yet fertilizer-based nitrogen inputs remain high and have increased in parts of the Suwannee River Basin (Katz et al. 1999, pp. 49-50; FDEP 2014a, pp. 106-123).

For the 2000 water year, the FDEP determined that the middle Suwannee and lower Santa Fe watersheds contributed more than three-quarters of the basin-wide nitrate-nitrogen load, although these watersheds comprise less than 20 percent of the drainage area (FDEP 2003, p. 35). In 2007, the FDEP (2008, pp. 40-41) found that more than 40 percent of total nitrogen in the middle and lower Suwannee River Basin originates from fertilizer inputs, but also that dairy, poultry, and beef production are prominent nitrogen contributors in the area. The same report showed that atmospheric deposition contributed less than 20 percent of total nitrogen in the area (FDEP 2008, pp. 40-41), suggesting that modern nitrogen concentrations in the basin greatly surpass historical background levels. In addition, the area is also naturally rich in phosphorus, and active and inactive phosphate mining operations exist in the central part of the basin. Historically, discharges from phosphate-fertilizer production have been correlated with major changes in physiochemical properties of basin waters. Spikes in total phosphorus, fluoride, and soluble inorganic nitrogen, as well as depressed dissolved oxygen (DO) levels, were observed immediately downstream of the mouth of Swift Creek, a tributary accepting phosphate mine effluent (FDEP 1985, pp. iv-19).

Section 303(d) of the Clean Water Act (33 U.S.C. 1251 et seq.) requires States to identify waters that do not fully support their designated use classification. These impaired waters are placed on the State's 303(d) list, and a total maximum daily load (TMDL) must be developed for the pollutant of concern. A TMDL is an estimate of the total load of pollutants that a segment of water can receive without exceeding applicable water quality criteria. The Georgia Environmental Protection Division's (GEPD) draft 303(d) list for 2014 identifies a total of 64 impaired stream segments (a total of 695 stream miles) within the Suwannee River Basin (GEPD 2014, pp. 263-273). The list of causes of impairment with established TMDLs in Georgia include mercury, lead, low dissolved oxygen (DO), fecal coliform, pH, algae, and condition of the macroinvertebrate community (GEPD 2014, pp. 263-273). The potential sources of these violations are primarily attributed to nonpoint or unknown sources but also to municipal facilities and urban runoff. FDEP's 303(d) list identifies 52 impaired stream segments or water bodies in the Suwannee River Basin. Florida's list identifies coliform bacteria, specific conductance, dissolved oxygen, nutrients, and unionized ammonia as impaired parameters (FDEP 2014b). Impairments within the range of the Suwannee moccasinshell include mercury in the lower Suwannee River, and DO and nutrients (algal mats) in the lower Santa Fe River (FDEP 2003 pp. 138-139).

Perhaps the most significant threat to the Suwannee moccasinshell is flow reduction due to the withdrawal of groundwater for agricultural purposes. Stream flows in the Suwannee River Basin are heavily dependent on groundwater contributions. Sufficient groundwater flows are essential for maintaining good mussel habitat in the Basin (Williams et al. 2014, p. 46). In the past 25 years, center pivot irrigation has increased in the Apalachicola-Chattahoochee-Flint (ACF) River Basin which borders the Suwannee River Basin to the northwest (Torak et al. 2010, p. 2). Most of the groundwater used for irrigation in the ACF Basin is withdrawn from the Upper Floridan aquifer. Increased pumping in the ACF Basin has lowered groundwater levels along the boundary with neighboring Ochlockonee and Suwannee River Basins by more than 24 feet. In southeastern Colquitt County, GA, the aquifer has experienced unprecedented 40- to 50-foot declines since 1969 (Torak et al. 2010, p. 44). Periods of extreme dry conditions causing insufficient recharging flows into the Upper Floridan aquifer occurred in the 1980s-2000s (Torak et al. 2010, p. 47). The lower aquifer levels reduced the hydraulic gradient, thus the amount of groundwater flowing south and east into the Suwannee Basin (Torak et al. 2010, pp. 2, 40).

Declines in groundwater levels have the potential to lower stream base flows by decreasing the amount groundwater discharged to streams. This may also reduce high-magnitude flows (10,000-15,000-cubic feet per second), which could decrease floodplain connectivity and the transfer of matter and energy from overbank to riverine systems (Light et al. 2002, p. 85; Pringle 2003, entire). Mean annual flow discharge in the lower Suwannee River near Wilcox, FL, has declined more than 30 percent between 1942 and 2012 (USGS 2014). Similar discharge declines of approximately 30 percent have been observed in the Santa Fe River near Fort White between 1928 and 2013 (USGS 2014). Reductions in flow can alter hydraulically mediated sediment sorting throughout the river, which may displace or otherwise alter habitat for Suwannee moccasinshell and its host fishes. Groundwater pumping during long periods of drought can result in extremely reduced flow rates. The upper reaches of the Santa Fe River mainstem and the New River, a major tributary, have ceased to flow due to groundwater pumping during drought (Williams 2015, p. 9). Biologists conducting mussel surveys on the Santa Fe River near Worthington Springs during a dry period in June 2011 observed that a section of the channel was completely dewatered (FFWCC 2011a, p. 2). While pumping does not completely dewater the Withlacoochee River, flow rates are greatly reduced (Williams 2015 p. 9). Reduced flows may exacerbate drought conditions (elevating temperature, pH, and pollutant concentrations (causing biotic die-off, and reducing DO), which in turn may have lethal or other harmful effects (prematurely aborting glochidia, reduced growth rates) to the species, or may cause stranding mortality.

Numerous potential sources of sand and silt sediments occur throughout the basin, and include development, silviculture, livestock grazing, croplands, and unpaved roads. Habitat may be degraded or destroyed in localized areas where sediments accumulate, and suspended fine particles can increase turbidity levels for considerable distances downstream. High levels of suspended sediments may reduce mussel feeding and respiratory efficiency (Dennis 1984, pp. 207-212; Brim Box and Mossa 1999, pp. 101-102). Highly turbid conditions may also affect mussel recruitment by impeding the ability of sight-feeding fishes to find glochidia and mussel lures. The Suwannee moccasinshell uses small mantel lures to attract its darter host fish (see Habitat and Biology section above) and, therefore, is reliant on good water clarity during times that it is reproducing. Another important issue related to sedimentation is that it may serve as a vehicle for pollutants (like pesticides and surfactants) to enter streams (Haag 2012, p. 378).

The Suwannee River main channel is relatively unimpacted by sedimentation, where inputs are generally low and impacts are mostly localized; however, sedimentation is a problem in the Santa Fe River sub-basin. Surface drainage is more prevalent in the Santa Fe watershed, which is more developed because of its proximity to Gainesville, FL, and several other incorporated areas (FDEP 2003, p. 23). Excessive silt sediment has been cited as a reason for the decline of mussel populations in the Santa Fe sub-basin (FFWCC 2011b, p. 14) and is considered a factor in the decline of the Suwannee moccasinshell in that system.

We are not aware of any conservation efforts that may help ameliorate threats specific to the Suwannee moccasinshell. However, the moccasinshell may be indirectly benefited by Federal, State, local, and private programs that acquire or manage lands within the basin, particularly along stream corridors. Florida's Suwannee River Water Management District (SRWMD) owns, manages, or co-manages a significant portion of the basin's riparian lands (more than 48,000 acres, CBI 2010) adjacent to or upstream of Suwannee moccasinshell habitats. Tracts are managed to maintain adequate water supply and water quality for natural systems by preserving riparian habitats and restricting development (SRWMD 2014, p. 3). The SRWMD also established minimum flows and levels for the river channel in the lower basin, downstream of Fanning Springs. Minimum flow and level criteria were not designed with specific consideration for freshwater mussels, but do establish a limit at which further withdrawals would be detrimental to water resources, taking into consideration fish and wildlife habitats, the passage of fish, sediment loads, and water quality, among others (SRWMD 2005, pp. 6-8).

Habitat degradation is occurring throughout the entire range of the Suwannee moccasinshell and is due primarily to pollutants discharged from municipal and industrial facilities, polluted runoff from agricultural areas, and reduced flows as a result of groundwater pumping and drought. In portions of the species' range, sedimentation has also impacted the species' habitat. These threats are greater in the two tributary systems, as evidenced by the species' possible disappearance from the Withlacoochee River, and its dramatic decline in the Santa Fe River sub-basin. Currently, nearly the entire population resides in the middle and lower reach of the Suwannee River main channel. The two greatest threats to the species, pollutants and reduced flows, are somewhat attenuated in the main channel, where flows are generally sustained and pollutant concentrations may be diluted by higher flow volumes. While there are programs in place that may indirectly alleviate some detrimental impacts on aquatic habitats, there currently are no conservation efforts designed specifically to protect or recover Suwannee moccasinshell populations. Therefore, we conclude that habitat degradation is presently a significant threat to Suwannee moccasinshell populations in the Withlacoochee and Santa Fe River sub-basins, and a moderate threat to populations in the Suwannee River main channel. This threat is expected to continue into the future and, because it is linked to human activities, is expected to increase as the human population within the Suwannee River Basin grows.

The Suwannee moccasinshell is not a commercially valuable species, and the Suwannee River is not subject to commercial mussel harvesting activities. Suwannee moccasinshell individuals have been taken for scientific and private collections in the past, but collecting is not considered a factor in its decline. Collection interest may increase as the Suwannee moccasinshell becomes an interest of scientific study, and as its rarity becomes better known. However, individuals are very difficult to locate because the species occurs in a large mainstem river in low abundance. Therefore, we do not consider overutilization to be a threat to the Suwannee moccasinshell at this time.

Juvenile and adult mussels are preyed upon by several aquatic predators (for example, dragonfly larvae, crayfishes, turtles, and some fishes), and are prey items for some terrestrial species (for example, raccoon, otter, feral hogs, and birds) (summarized in Hart and Fuller 1974, pp. 225-240; and in Williams et al. 2014, pp. 90-91). Although predation by native predators is a natural occurrence, it may exacerbate declines in mussel populations already diminished by other threats (Neves and Odom 1989, p. 940). However, we have no specific information indicating that predation is negatively impacting Suwannee moccasinshell populations.

Mussels commonly are hosts for a variety of parasites, including trematodes, copepods, and water mites, and also harbor bacteria and viruses (Grizzle and Brunner 2007, p. 4; Haag 2012, pp. 382-383). Heavy infestations by mites and trematodes have shown to adversely affect mussel reproductive and physiological fitness (Gangloff 2008, pp. 28-30). In addition, exposure to stressors like pollutants can weaken mussel immune systems, making them more prone to diseases. However, the role of diseases in mussel declines has received little attention, and diseases of freshwater mussels remain largely unstudied (Grizzle and Bruner 2007, p. 6; Haag 2012, p. 382). We have no specific information indicating that disease is negatively impacting Suwannee moccasinshell populations. Therefore, we do not consider disease or predation to be threats to the Suwanee moccasinshell at this time.

Point source discharges within the range of the Suwannee moccasinshell have been reduced since the inception of the Clean Water Act, but this statute still may not provide adequate protection for sensitive aquatic organisms like freshwater mussels, which can be impacted by extremely low levels of pollutants. Municipal wastewater plants continue to discharge large amounts of effluent and, in some circumstances, in excess of permitted levels (see discussion under Factor A). There is no specific information on the sensitivity of the Suwannee moccasinshell to common industrial and municipal pollutants, and very little information on other freshwater mussel species. Current State and Federal regulations regarding pollutants are designed to be protective of aquatic organisms; however, freshwater mollusks may be more susceptible to some pollutants than the test organisms commonly used in bioassays. Additionally, water quality criteria may not incorporate data available for freshwater mussels (March et al. 2007, pp. 2,066-2,067). A multitude of bioassays conducted on 16 mussel species (summarized by Augspurger et al. 2007, pp. 2025-2028) show that freshwater mollusks are more sensitive than previously known to some chemical pollutants, including chlorine, ammonia, copper, fungicides, and herbicide surfactants. Another study found that nickel and chlorine were toxic to a federally threatened mussel species at levels below the current criteria (Gibson 2015, pp. 90-91). The study also found the mussel was sensitive to SDS (sodium dodecyl sulfate), a surfactant commonly used in household detergents, for which water quality criteria do not currently exist.

Several studies have demonstrated that the criteria for ammonia developed by EPA in 1999 were not protective of freshwater mussels (Augspurger et al. 2003, p. 2,571; Newton et al. 2003, pp. 2,559-2,560; Mummert et al. 2003, pp. 2,548-2,552). However, in 2013 EPA revised its recommended criteria for ammonia. The new criteria are more stringent and reflect new toxicity data on sensitive freshwater mollusks (78 FR 52192, August 22, 2013; p. 2). Georgia and Florida have not yet adopted the new ammonia criteria. Although Florida's next triennial review will occur in 2015 and Georgia's in 2016, NPDES permits are valid for 5 years, so even after the new criteria are adopted, it could take several years before facilities must comply with the new limits.

In summary, despite existing authorities such as the Clean Water Act, pollutants continue to impair the water quality throughout the current range of the Suwannee moccasinshell. State and Federal regulatory mechanisms have helped reduce the negative effects of point source discharges since the 1970s, yet these regulations are difficult to implement and regulate. While new water quality criteria are being developed that take into account more sensitive aquatic species, most criteria currently do not. Thus, we conclude that existing regulatory mechanisms do not adequately protect the Suwannee moccasinshell.

The Gulf coastal region is prone to extreme hydrologic events. Extended droughts result from persistent high-pressure systems, which inhibit moisture from the Gulf of Mexico from reaching the region (Jeffcoat et al. 1991, pp. 163-170). Warm, humid air from the Gulf of Mexico can produce strong frontal systems and tropical storms resulting in heavy rainfall events that cause severe flooding (Jeffcoat et al. 1991, pp. 163-170). Although floods and droughts are a natural part of the hydrologic processes that occur in these river systems, these events may exacerbate the decline of mussel populations suffering the effects of other threats. During high flows, flood scour can dislodge mussels (particularly juveniles) where they may be injured, buried, or swept into unsuitable habitats, or mussels may be stranded and perish when flood waters recede (Vannote and Minshall 1982, p. 4,105; Tucker 1996, p. 435; Hastie et al. 2001, pp. 107-115; Peterson et al. 2011, unpaginated). Flood scour generally is attenuated in larger stream channels but can radically alter smaller streams and cause mussel mortality (Hastie et al. 2001, pp. 107-115; Peterson et al. 2011, unpaginated).

During drought, stream channels may be dewatered entirely, or become disconnected pools where mussels are exposed to higher water temperatures, lower dissolved oxygen levels, and predators. Johnson et al. (2001, p. 6) monitored mussel responses during a severe drought in 2000 in tributaries of the lower Flint River in Georgia, and found that most mortality occurred when dissolved oxygen levels dropped below 5 mg/L. Increased demand for surface and ground water resources for irrigation and human consumption during drought can cause drastic reductions in stream flows and alterations to hydrology (Golladay et al. 2004, p. 504; Golladay et al. 2007 unpaginated). Extended periods of drought have occurred in the region during the last two decades (Torak et al. 2010, p. 47). Substantial declines in mussel diversity and abundance as a direct result of drought have been documented in smaller southeastern streams; however, assemblages in larger streams may be relatively unaffected (Golladay et al. 2004, pp. 494-503; Haag and Warren 2008, p. 1165). Reduced flows as a result of drought and water consumption has been cited as a factor negatively affecting mussels in the Suwannee River Basin (FFWCC 2011b, p. 14), and has been identified as a threat to Suwannee moccasinshell populations in the Withlacoochee and Santa Fe Rivers (Williams 2015, p. 9)

The linear nature of the Suwannee moccasinshell's habitat and its reduced range makes it vulnerable to contaminant spills. Spills as a result of transportation accidents are a constant potential threat to the species, as numerous highways and railroads traverse the basin. Spills emanating from industrial, agricultural, and municipal facilities are a threat as numerous potential sources are present within the basin, and these spills have occurred in the past. As discussed under Factor A, spills at the municipal WWTP in Valdosta, GA, have leaked raw sewage into the Withlacoochee River on multiple occasions, and the PCS Phosphate Company, Inc. mining operation has had periodic overflows of effluent ponds. Nearly the entire moccasinshell population resides within the Suwannee River main channel; therefore, a spill has the potential to impact a large portion of the population, depending on the type of contaminant and its concentration, amount, and location. In addition, because the species has limited ability to disperse, it may not be able recolonize areas after conditions have improved.

Our analyses under the Act include consideration of ongoing and projected changes in climate. The terms “climate” and “climate change” are defined by the Intergovernmental Panel on Climate Change (IPCC). “Climate” refers to the mean and variability of different types of weather conditions over time, with 30 years being a typical period for such measurements, although shorter or longer periods also may be used (IPCC 2007, p. 78). The term “climate change” thus refers to a change in the mean or variability of one or more measures of climate (e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2007, p. 78). Various types of changes in climate can have direct or indirect effects on species. These effects may be positive, neutral, or negative and they may change over time, depending on the species and other relevant considerations, such as the effects of interactions of climate with other variables (e.g., habitat fragmentation) (IPCC 2007, pp. 8-14, 18-19). In our analyses, we use our expert judgment to weigh relevant information, including uncertainty, in our consideration of various aspects of climate change.

There is a growing concern that climate change may lead to increased frequency of severe storms and droughts (McLaughlin et al. 2002, p. 6,074; Golladay et al. 2004, p. 504; Cook et al. 2004, p. 1,015). The present conservation status, complex life histories, and specific habitat requirements of freshwater mussels suggest that they may be quite sensitive to climate change (Hastie et al. 2003, p. 45). Specific effects of climate change to mussels, their habitat, and their fish hosts could include changes in hydrologic and temperature regimes, the timing and levels of precipitation causing more frequent and severe floods and droughts, and alien species introductions.

Mussel distributions seem to be closely associated with complex hydraulic metrics (Morales et al. 2006 pp. 669-673; Zigler et al. 2008, p. 358) that may be altered by climate change. Mussels are particularly vulnerable to these changes since they are generally sessile and restricted in their ability to adjust their range in response to hydrology and physiochemical alterations mediated by climate change (Strayer 2008, p. 30). Additionally, increases in temperature and reductions in flow may lower dissolved oxygen levels in interstitial habitats, which can be lethal to juveniles (Sparks and Strayer 1998, pp. 131-133). Effects to mussel populations from these environmental changes could include reduced abundance and biomass, altered species composition, and host fish considerations (Galbraith et al. 2010, pp. 1,180-1,182). Since ammonia concentrations may increase with increasing temperatures and low stream flow (Cherry et al. 2005, p. 378; Cooper et al. 2005, p. 381), nitrogen-mediated threats may be intensified by climate change. In addition, saltwater encroachment, as a result of rising sea levels, has the potential to impact freshwater habitats in the lower reaches of coastal rivers.

Long-term sea level trends available from the Cedar Key tide gage suggest the local sea level is rising about 1.8 mm (0.7 inches) per year based on data from 1914 to 2006 (Thom et al. 2015, pp. 47-48). At this rate, this is equivalent to 0.14 meters (0.46 feet) by 2100. However, all indications are that sea level rise (SLR) is accelerating (Thom et al. 2015, p. 47), and, although there is a range of estimates, recent studies suggest that global mean sea level will rise at least 0.2 meters (0.66 ft) and no more than 2.0 meters (6.6 ft) by 2100 (Parris et al. 2012, pp. 1-2).

The effects of climate change may amplify stressors currently impacting the Suwannee moccasinshell, including the prospect of more frequent and intense droughts and increased temperatures, which would further reduce flows, increase pollutant toxicity levels, and exacerbate current problems of low DO and excessive algae growth (see discussions under Factor A). Saltwater encroachment also has the potential to impact moccasinshell populations in the lower river, especially during times of low flow conditions. The variables related to climate change are complex, and it is difficult to predict all of the possible ways climate change will affect Suwannee moccasinshell populations and habitat. However, information available is sufficient to indicate that climate change is a significant threat to the Suwannee moccasinshell in the future, as it will likely exacerbate certain stressors already affecting the species, such as reduced flows and degraded water quality.

The Suwannee moccasinshell's reduced range and small population size may increase its vulnerability to many threats. Species with small ranges, few populations, and small or declining population sizes are the most vulnerable to extinction (Primack 2008, p. 137). The effects of certain environmental pressures, particularly habitat degradation and loss, catastrophic weather events, and introduced species, are greater when population size is small (Soulé 1980, pp. 33, 71; Primack 2008, pp. 133-137, 152). Suwannee moccasinshell populations are small and declining and are vulnerable to habitat degradation, droughts, and competition from the introduced Asian clam. In addition, its current range is relatively small, consisting of a stream channel segment of about 103 miles in length (see Distribution and Abundance discussion).

The Asian clam (Corbicula fluminea) was first detected in eastern Gulf drainages in the early 1960s and is presently widespread in the Suwannee River Basin. Anecdotal observations suggest that, when the Asian clam became established in other Gulf coast drainages, native mussel abundance declined drastically (Heard 1975, p. 2; Shelton 1995, p. 4). It is unknown, however, if the Asian clam competitively excluded the native mussels, are tolerant of whatever caused them to disappear, or, as Haag (2012, p. 371) suggests, the Asian clam is a poor competitor and can only become dense after a decline in mussel abundance. Mechanisms by which the Asian clam may negatively affect mussels include as a competitor for food and space; by ingesting mussel sperm, glochidia, and newly metamorphosed juveniles; and by displacing newly metamorphosed mussels from the substrate, causing them to be washed downstream (Neves and Widlak 1987, p. 6; Leff et al. 1990, p. 415; Strayer 1999, p. 82; Yeager et al. 2000, pp. 255-257). Although the specific interaction between the Asian clam and native mussels is not well understood, enough information exists to conclude that dense Asian clam populations would negatively affect juvenile mussel survival (Haag 2012, p. 370). Surveys within the range of the Suwannee moccasinshell found Asian clam densities varied from relatively low in some areas to relatively high in other areas (S. Pursifull 2014 pers. obs.). The introduced Asian clam is negatively affecting the Suwannee moccasinshell, although we consider this threat to be low at present.

The flathead catfish (Pylodictis olivaris) has been introduced to the Suwannee River Basin and may be adversely impacting native fish populations. As discussed in the Habitat and Biology section above, the Suwannee moccasinshell requires a fish host in order to complete its life cycle, and the blackbanded darter and the brown darter were found to serve as larval hosts for the moccasinshell. The flathead catfish is a large predator native to the central United States, and since its introduction outside its native range, it has altered the composition of native fish populations through predation (Boschung and Mayden 2004, p. 350). Many feeding studies have found that flathead catfish prey heavily on other fishes, especially sunfishes (Centrarchidae) (Weller and Robbins 1999, p. 40; Pine et al. 2005, p. 904). One study in the Flint River system in Georgia found that young-of-the-year flatheads consumed several fish species including darters (Etheostoma spp.) (Quinn 1988, p. 88). The loss or reduction of darters, which are essential during the moccasinshell's parasitic larval stage, would affect the Suwannee moccasinshell's ability to recruit and disperse. However, it is not known if the specific darter species needed by this mussel to reproduce are being predated by introduced flatheads; therefore, it is difficult for us to evaluate this potential threat at this time.

In summary, the Suwannee moccasinshell is adversely affected by other natural or manmade factors including droughts that (along with groundwater consumption) cause reduced flows, past and future contaminant spills, and the introduced Asian clam. In addition, numerous future impacts associated with changing climatic patterns (increased drought frequency, altered water quality, saltwater encroachment) are anticipated, some of which could intensify stressors currently affecting the species, including reduced flows and low DO. For this reason, problems related to reduced flows and degraded water quality are expected to increase in the future. Finally, the Suwannee moccasinshell's small population size and restricted range makes it more vulnerable to certain threats. Therefore, we find that these threats, as a whole, pose a significant threat to the Suwannee moccasinshell, both now and continuing into the future. The Suwannee moccasinshell may also be affected by flood events, and predation of its host fishes by introduced flathead catfish. However, we do not have information indicating that these are currently acting on the species at this time.

We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats to the Suwannee moccasinshell. The primary reason for the Suwannee moccasinshell's decline is the degradation of its habitat due to polluted runoff from agricultural lands, discharges from industrial and municipal wastewater sources and from mining operations, and decreased flows due to groundwater extraction and drought (Factor A). These threats occur throughout its range, but are more intense in the two tributaries, the Withlacoochee and Santa Fe River systems. In portions of its range, sedimentation has also impacted its habitat. Other threats to the species include State and Federal water quality standards that are inadequate to protect sensitive aquatic organisms like mussels (Factor D); contaminant spills as a result of transportation accidents or from industrial, agricultural, and municipal facilities (Factor E); increased drought frequency as a result of changing climatic conditions (Factor E); greater vulnerability to certain threats because of small population size and range (Factor E); and competition and disturbance from the introduced Asian clam (Factor E). These threats have resulted in the decline of the species throughout its range, and pose the highest risk to populations in the two tributary systems, as evidenced by the species' decline and possible disappearance in the Withlacoochee River, and its decline in the Santa Fe River sub-basin. In addition, the species likely has a limited ability to disperse and, therefore, may not be able recolonize areas from which it has been extirpated. Currently, nearly the entire population resides in the middle and lower reach of the Suwannee River main channel, where the two greatest threats, pollutants and reduced flows, are attenuated by higher flow volumes. Therefore, Suwannee moccasinshell populations in the Withlacoochee and Santa Fe River sub-basins are presently facing threats that are high in magnitude, and populations in the Suwannee River main channel are presently facing threats that are moderate in magnitude. Most of these threats, including reduced flows, pollutants, droughts, and climate change, are expected to increase in the future.

The Act defines an endangered species as any species that is “in danger of extinction throughout all or a significant portion of its range” and a threatened species as any species “that is likely to become endangered throughout all or a significant portion of its range within the foreseeable future.” We find that the Suwannee moccasinshell is likely to become endangered throughout all or a significant portion of its range within the foreseeable future based on the overall severity and immediacy of threats currently impacting the species. The Suwannee moccasinshell's range and abundance have been reduced, and its remaining habitat and populations are threatened by a variety of factors acting in combination to reduce the overall viability of the species. The risk of becoming endangered is high because remaining Suwannee moccasinshell populations in the main channel are small and numerous threats impact those populations. However, we find that endangered species status is not appropriate, because despite low population densities and numerous threats, the populations in the main channel, which are the largest, appear to be stable, which has been attributed to the threats being attenuated and the streambed habitat being stable. Therefore, on the basis of the best available scientific and commercial information, we propose listing the Suwannee moccasinshell as threatened in accordance with sections 3(6) and 4(a)(1) of the Act.

Under the Act and our implementing regulations, a species may warrant listing if it is endangered or threatened throughout all or a significant portion of its range. Because we have determined that the Suwannee moccasinshell is threatened throughout all of its range, no portion of its range can be “significant” for purposes of the definitions of “endangered species” and “threatened species.” See the Final Policy on Interpretation of the Phrase “Significant Portion of Its Range” in the Endangered Species Act's Definitions of “Endangered Species” and “Threatened Species” (79 FR 37578; July 1, 2014).

Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 3(3) of the Act (16 U.S.C. 1532(3)) also defines the terms “conserve,” “conserving,” and “conservation” to mean to use and the use of all methods and procedures which are necessary to bring any endangered species or threatened species to the point at which the measures provided pursuant to this chapter Act are no longer necessary.

Section 4(a)(3) of the Act, as amended, and implementing regulations (50 CFR 424.12), require that, to the maximum extent prudent and determinable, the Secretary shall designate critical habitat at the time the species is determined to be an endangered or threatened species. Our regulations in title 50 of the Code of Federal Regulations (50 CFR 424.12(a)(1)) state that the designation of critical habitat is not prudent when one or both of the following situations exist:

(1) The species is threatened by taking or other human activity, and identification of critical habitat can be expected to increase the degree of threat to the species, or

(2) Such designation of critical habitat would not be beneficial to the species.

There is currently no imminent threat of take attributed to collection or vandalism under Factor B for this species, and identification and mapping of critical habitat is not expected to initiate any such threat. In the absence of finding that the designation of critical habitat would increase threats to a species, if there are any benefits to a critical habitat designation, a finding that designation is prudent is warranted. Here, the potential benefits of designation include: (1) Triggering consultation under section 7 of the Act, in new areas for actions in which there may be a Federal nexus where it would not otherwise occur because, for example, it is unoccupied; (2) focusing conservation activities on the most essential features and areas; (3) providing educational benefits to State or county governments or private entities; and (4) preventing people from causing inadvertent harm to the species.

Because we have determined that the designation of critical habitat will not likely increase the degree of threat to the species and may provide some measure of benefit, we determine that designation of critical habitat is prudent for the Suwannee moccasinshell.

Our regulations (50 CFR 424.12(a)(2)) further state that critical habitat is not determinable when one or both of the following situations exists: (1) Information sufficient to perform required analysis of the impacts of the designation is lacking; or (2) the biological needs of the species are not sufficiently well known to permit identification of an area as critical habitat.

Delineation of critical habitat requires, within the geographical area occupied by the Suwannee moccasinshell, identification of the physical or biological features essential to the conservation of the subspecies. While we have significant information on the habitat of the species, we need more information on biological needs of the species (i.e., specific habitat features on the landscape) in order to identify specific areas appropriate for critical habitat designation. In addition, as we have not determined the areas that may qualify for designation, the information sufficient to perform a required analysis of the impacts of the designation is lacking. Accordingly, we find designation of critical habitat to be not determinable at this time.

Conservation measures provided to species listed as endangered or threatened under the Act include recognition, recovery actions, requirements for Federal protection, and prohibitions against certain practices. Recognition through listing results in public awareness, and conservation by Federal, State, Tribal, and local agencies, private organizations, and individuals. The Act encourages cooperation with the States and other countries and calls for recovery actions to be carried out for listed species. The protection required by Federal agencies and the prohibitions against certain activities are discussed, in part, below.

The primary purpose of the Act is the conservation of endangered and threatened species and the ecosystems upon which they depend. The ultimate goal of such conservation efforts is the recovery of these listed species, so that they no longer need the protective measures of the Act. Subsection 4(f) of the Act calls for the Service to develop and implement recovery plans for the conservation of endangered and threatened species. The recovery planning process involves the identification of actions that are necessary to halt or reverse the species' decline by addressing the threats to its survival and recovery. The goal of this process is to restore listed species to a point where they are secure, self-sustaining, and functioning components of their ecosystems.

Recovery planning includes the development of a recovery outline shortly after a species is listed and preparation of a draft and final recovery plan. The recovery outline guides the immediate implementation of urgent recovery actions and describes the process to be used to develop a recovery plan. Revisions of the plan may be done to address continuing or new threats to the species, as new substantive information becomes available. The recovery plan also identifies recovery criteria for review of when a species may be ready for downlisting or delisting, and methods for monitoring recovery progress. Recovery plans also establish a framework for agencies to coordinate their recovery efforts and provide estimates of the cost of implementing recovery tasks. Recovery teams (composed of species experts, Federal and State agencies, nongovernmental organizations, and stakeholders) are often established to develop recovery plans. If this species is listed as proposed, a recovery outline, draft recovery plan, and the final recovery plan would be made available on our Web site (http://www.fws.gov/endangered), or from our Panama City Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

Implementation of recovery actions generally requires the participation of a broad range of partners, including other Federal agencies, States, Tribes, nongovernmental organizations, businesses, and private landowners. Examples of recovery actions include habitat restoration (e.g., restoration of native vegetation), research, captive propagation and reintroduction, and outreach and education. The recovery of many listed species cannot be accomplished solely on Federal lands because their range may occur primarily or solely on non-Federal lands. To achieve recovery of these species requires cooperative conservation efforts on private, State, and Tribal lands. If this species is listed, funding for recovery actions will be available from a variety of sources, including Federal budgets, State programs, and cost share grants for non-Federal landowners, the academic community, and nongovernmental organizations. In addition, pursuant to section 6 of the Act, the States of Florida and Georgia would be eligible for Federal funds to implement management actions that promote the protection or recovery of the Suwannee moccasinshell. Information on our grant programs that are available to aid species recovery can be found at: http://www.fws.gov/grants.

Although the Suwannee moccasinshell is only proposed for listing under the Act at this time, please let us know if you are interested in participating in conservation efforts for this species. Additionally, we invite you to submit any new information on this species whenever it becomes available and any information you may have for conservation planning purposes (see FOR FURTHER INFORMATION CONTACT).

Section 7(a) of the Act requires Federal agencies to evaluate their actions with respect to any species that is proposed or listed as an endangered or threatened species and with respect to its critical habitat, if any is designated. Regulations implementing this interagency cooperation provision of the Act are codified at 50 CFR part 402. Section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any action that is likely to jeopardize the continued existence of a species proposed for listing or result in destruction or adverse modification of proposed critical habitat. If a species is listed subsequently, section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the species or destroy or adversely modify its critical habitat. If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency must enter into consultation with the Service.

Federal agency actions within the species' habitat that may require conference or consultation or both as described in the preceding paragraph include management and any other landscape-altering activities on Federal lands administered by the Service and the U.S. Department of Agriculture's (USDA) U.S. Forest Service; issuance of section 404 Clean Water Act permits by the U.S. Army Corps of Engineers; construction and maintenance of roads, highways, or bridges by the U.S. Department of Transportation's Federal Highway Administration; and funding assistance for various projects administered by USDA's Natural Resources Conservation Service and the Federal Emergency Management Agency.

Under section 4(d) of the Act, the Service has discretion to issue regulations that we find necessary and advisable to provide for the conservation of threatened species. The Act and its implementing regulations set forth a series of general prohibitions and exceptions that apply to threatened wildlife. The prohibitions of section 9(a)(1) of the Act, as applied to threatened wildlife and codified at 50 CFR 17.31, make it illegal for any person subject to the jurisdiction of the United States to take (which includes harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect; or to attempt any of these) threatened wildlife within the United States or on the high seas. In addition, it is unlawful to import; export; deliver, receive, carry, transport, or ship in interstate or foreign commerce in the course of commercial activity; or sell or offer for sale in interstate or foreign commerce any listed species. It is also illegal to possess, sell, deliver, carry, transport, or ship any such wildlife that has been taken illegally. Certain exceptions apply to employees of the Service, the National Oceanic and Atmospheric Administration's National Marine Fisheries Service, other Federal land management agencies, and State conservation agencies.

We may issue permits to carry out otherwise prohibited activities involving threatened wildlife under certain circumstances. Regulations governing permits are codified at 50 CFR 17.32. With regard to threatened wildlife, a permit may be issued for the following purposes: for scientific purposes, to enhance the propagation or survival of the species and for incidental take in connection with otherwise lawful activities. There are also certain statutory exemptions from the prohibitions, which are found in sections 9 and 10 of the Act.

It is our policy, as published in the Federal Register on July 1, 1994 (59 FR 34272), to identify to the maximum extent practicable at the time a species is listed, those activities that would or would not constitute a violation of section 9 of the Act. The intent of this policy is to increase public awareness of the effect of a proposed listing on proposed and ongoing activities within the range of species proposed for listing. Based on the best available information, the following activities may potentially result in a violation of section 9 the Act; this list is not comprehensive:

Activities that the Service believes could potentially harm the Suwannee moccasinshell and result in “take,” include, but are not limited to:

(1) Unauthorized handling or collecting of the species;

(2) Destruction or alteration of the species' habitat by discharge of fill material, dredging, snagging, impounding, channelization, or modification of stream channels or banks;

(3) Discharge of pollutants into a stream or into areas hydrologically connected to a stream occupied by the species; and

(4) Diversion or alteration of surface or ground water flow.

Questions regarding whether specific activities would constitute a violation of section 9 of the Act should be directed to the Panama City Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

We are required by Executive Orders 12866 and 12988 and by the Presidential Memorandum of June 1, 1998, to write all rules in plain language. This means that each rule we publish must:

(1) Be logically organized;

(2) Use the active voice to address readers directly;

(3) Use clear language rather than jargon;

(4) Be divided into short sections and sentences; and

(5) Use lists and tables wherever possible.

If you feel that we have not met these requirements, send us comments by one of the methods listed in ADDRESSES. To better help us revise the rule, your comments should be as specific as possible. For example, you should tell us the numbers of the sections or paragraphs that are unclearly written, which sections or sentences are too long, the sections where you feel lists or tables would be useful, etc.

We have determined that environmental assessments and environmental impact statements, as defined under the authority of the National Environmental Policy Act, need not be prepared in connection with listing a species as an endangered or threatened species under the Act. We published a notice outlining our reasons for this determination in the Federal Register on October 25, 1983 (48 FR 49244).

A complete list of references cited in this rulemaking is available on the Internet at http://www.regulations.gov and upon request from the Panama City Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

The primary authors of this proposed rule are the staff members of the Panama City Ecological Services Field Office.

Accordingly, we propose to amend part 17, subchapter B of chapter I, title 50 of the Code of Federal Regulations, as set forth below: