The Gray Wolf Under the Endangered Species November 25, 2020 Act (ESA): A Case Study in Listing and Delisting Erin H. Ward Challenges Legislative Attorney Under the Endangered Species Act of 1973 (ESA or the Act; 16 U.S.C. §§ 1531-1544), the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) (together, the Services) determine which species to "list" as "“list” as “endangered species"” or "“threatened species," ” terms defined in the Act. Species, subspecies, and distinct population segments (DPSs) may all be listed as "species"“species” under the Act. Listing a species invokes certain protections under the Act and a requirement that the Services develop a recovery plan to conserve the species. Listed species may be reclassified by the Services from threatened toA species listed as threatened may be reclassified as endangered or vice versa. The Services may also remove a species from the list, often called delisting, if itthe species no longer meets the definition of an endangered or threatened species. The Services list, reclassify, and delist species pursuant to statutory criteria and definitions through the agency rulemaking processthrough the agency rulemaking process, guided by statutory criteria and definitions. Persons may—and often do—challenge the legality of those final rules through litigation. When such challenges succeed, the court remands the rule to the applicable Service for further proceedings and may vacate the challenged rule.

The The case of the gray wolf (Canis lupus) presents a useful example ofexemplifies the legal issues that arise with listing and delisting species as threatened and endangered under the ESA and how FWS has addressed them. FWS first listed the gray wolf as endangered in 1967 under the Endangered Species Preservation Act (ESPA), a predecessor of the ESA. The gray wolf'’s status and regulation under the ESA and its predecessors have been the subjects of numerous FWS rules and court opinions. FWS'’s gray wolf rules show how the agency'’s approach to interpreting and implementing the ESA has evolved and highlight hurdles that may arise with species'’ status determinations.

As American pioneers settled the West, hunting and other human-caused mortality, spurred by federal and state bounties, brought the gray wolf to near extinction. By the 1960s, the only population remaining in the lower 48 states was in the northern Minnesota forests. FWS listed the eastern timber wolf (C. lupus lycaon, a gray wolf subspecies found in Minnesota) as endangered under the ESPA. By 1976, three more gray wolf subspecies—the Mexican wolf (C. lupus baileyi), the northern Rocky Mountain wolf (C. lupus irremotus), and the Texas wolf (C. lupus monstrabilis)—were listed as endangered under the ESA. In 1978, FWS combined all gray wolf subspecies listings into one listing for. One rule listed the entire gray wolf species as endangered in in the lower 48 states except Minnesota, which was listed as endangered, and a separate listing forrule listed the gray wolf in Minnesota as threatened. In the next few years, FWS created subspecies recovery plans that outlined management strategies and recovery criteria. In the 1990s, FWS reintroduced gray wolves to the northern Rocky Mountains and the Southwest as experimental populations under the ESA. Protected under the ESA from human-caused mortality, which FWS identified as the greatest threat to the species, gray wolf populations increased. In the 2000s, FWS tried on multiple occasions to reclassify or delist gray wolf DPSs it had determined were no longer in risk of extinction, but courts vacated many of the agency's rules. As of January 2020, the gray wolf is listed as endangered or threatened in the lower 48 states, except for a population in the northern Rocky Mountains.

FWS'’s rules. In 2015, FWS listed the Mexican wolf separately as endangered. In that rule, FWS adjusted the territory over which the gray wolf in the lower 48 states was endangered or threatened to exclude the Mexican wolf’s territory in Arizona and New Mexico. On November 3, 2020, FWS published a final rule delisting the gray wolf in the lower 48 states, with an effective date of January 4, 2021. This delisting rule does not affect the separate listing for the Mexican wolf as endangered. FWS’s efforts to recover the gray wolf under the ESA exemplify the regulatory and legal challenges that arise when listing and delisting species under the Act. From initial listing to recovery and reintroduction efforts to more recent attempts to delist the gray wolf, FWS has addressed in its regulatory actions such issues as uncertainties in gray wolf taxonomy, ambiguous statutory terms (e.g., "“foreseeable future"” and "“significant portion of its range"”), and the adequacy of state management plans. Stakeholders have questioned FWS'’s choices in comments to the proposed rules and have challenged many of the agency'’s gray wolf rules in court. Many of the legal challenges to FWS'’s delisting rules have succeeded, with courts vacating the rules and remanding them to the agency. The history of FWS'’s regulation of the gray wolf under the ESA and related litigation serve as a useful case study in how regulatory and legal challenges have shaped FWS'’s interpretation and application of key terms when listing and delisting species under the Act.

Under the Congressional Research Service link to page 6 link to page 10 link to page 12 link to page 13 link to page 14 link to page 15 link to page 17 link to page 17 link to page 21 link to page 21 link to page 22 link to page 23 link to page 23 link to page 24 link to page 25 link to page 29 link to page 29 link to page 30 link to page 31 link to page 34 link to page 36 link to page 36 link to page 39 link to page 40 link to page 40 link to page 42 link to page 44 link to page 7 link to page 8 link to page 16 link to page 16 link to page 18 link to page 20 link to page 27 link to page 46 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Contents Listing and Delisting Species Under the Endangered Species Act ........................................... 2 Administrative Law and Statutory Interpretation ............................................................ 6 History of Listing and Delisting the Gray Wolf .................................................................... 8 Listing and Recovery Efforts ....................................................................................... 9 Designating Distinct Population Segments (DPSs)........................................................ 10 Final Rule Designating Eastern, Western, and Southwestern DPSs in 2003.................. 11 Final Rules Designating and Delisting Western Great Lakes DPS in 2007 and Northern Rocky Mountain DPS in 2008 .............................................................. 13 Final Rules Designating and Delisting Western Great Lakes DPS and Northern Rocky Mountain DPS Except Wyoming in 2009 .................................................. 17 Final Rule Designating and Delisting Western Great Lakes DPS in 2011..................... 18 Final Rule Delisting the Gray Wolf in Wyoming in 2012 .......................................... 19 Delisting the Gray Wolf Listed Entities ....................................................................... 19 2013 Proposed Rule to Delist Gray Wolf Listed Entities and List Mexican Wolf........... 20 2020 Rule Delisting the Gray Wolf Listed Entities Except the Mexican Wolf ............... 21 Challenges When Listing and Delisting Species ................................................................. 25 Identifying the Species ............................................................................................. 25 Taxonomy ......................................................................................................... 26 Defining DPSs ................................................................................................... 27 Experimental Populations .................................................................................... 30 Qualifying as Endangered or Threatened ..................................................................... 32 “All or a Significant Portion of Its Range” ............................................................. 32 Foreseeable Future ............................................................................................. 35 Recovery and Delisting ............................................................................................ 36 Objective Recovery Criteria in Recovery Plans ....................................................... 36 State Management Plans...................................................................................... 38 Conclusion................................................................................................................... 40 Figures Figure 1. Petitioning the Secretary Under the Endangered Species Act .................................... 3 Figure 2. Listing and Delisting Species Under the Endangered Species Act .............................. 4 Figure 3. Distinct Population Segments (DPSs) in 2000 Proposed Rule and 2003 Final Rule ......................................................................................................................... 12 Figure 4. Western Great Lakes Distinct Population Segment ................................................ 14 Figure 5. Northern Rocky Mountain Distinct Population Segment ........................................ 16 Tables Table 1. Timeline: Gray Wolf Status by Population............................................................. 23 Table A-1. Gray Wolf Endangered Species Act Timeline ..................................................... 42 Congressional Research Service link to page 46 link to page 49 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Appendixes Appendix. Timeline ....................................................................................................... 42 Contacts Author Information ....................................................................................................... 45 Congressional Research Service link to page 12 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges nder the Endangered Species Act of 1973 (ESA or the Act),¹1 the U.S. Fish and Wildlife Service (FWS)) and the National Marine Fisheries Service (together, the Services) U determine which species to "list"“list” as “ as "endangered species"” or "“threatened species,",” terms defined in the Act.² .2 Species, subspecies, and distinct population segments (DPSs) may all al be listed as "species"“species” under the Act.³ 3 Listing a species invokes certain protections under the Act and a requirement that the Services develop a recovery plan to conserve the species.⁴ Listed species may be reclassified by the Services from threatened to4 A species listed as threatened may be reclassified as endangered or vice versa.⁵5 The Services may also remove a species from the list, often called delisting,⁶ if itcal ed delisting,6 if the species no longer meets the definition of an endangered or threatened species.⁷7 The Services list, reclassify, and delist species pursuant to statutory criteria and definitions through the agency rulemaking process.⁸ through the agency rulemaking process, guided by statutory criteria and definitions.8 Persons may—and often do—chal engedo—challenge the legality of those final rules through litigation.⁹9 When such challengeschal enges succeed, the court remands the rule to the applicable Service for further proceedings and may vacate the challenged rule.¹⁰

chal enged rule.10 The gray wolf (Canis lupus) presents a useful example of the legal issues that arise with listing and delisting species as threatened and endangered under the ESA and how FWS has addressed those issues. TheThe gray wolf was among the first species identified by federal law as endangered after being nearly hunted to near extinction in the lower 48 states.¹¹ .11 FWS has issued numerousnumerous rules in connection with its efforts to recover the gray wolf under the ESA.¹².12 Many of those rules have been challengedchal enged in court, and a number of them have been vacated and remanded to FWS.¹³ FWS 13 FWS has addressed issues such as uncertainties in gray wolf taxonomy, ambiguous statutory terms statutory terms (e.g., “(e.g., "foreseeable future"” and "“significant portion of its range"),”), and the adequacy of state management plans. This reportreport uses FWS's ’s regulation of the gray wolf under the ESA and related litigation litigation as a case study in how legal challengeschal enges have shaped FWS'’s interpretation of ESA provisions when listing and delisting species under the Act. The report begins by laying out general legal principles governing agency rulemaking under the ESA before reviewing the history of FWS's ’s actions to list, recover, and delist the gray wolf and subsequent litigation. and subsequent litigation. The report then uses this regulatory and litigation history to analyze specific issues that arise when listing and delisting species under the Act.

. 1 Pub. L. No. 93-205, 87 Stat. 884 (1973) (codified at 16 U.S.C. §§ 1531 – 1544). 2 16 U.S.C. § 1533. 3 Id. §§ 1532(16) & 1533(a). 4 Id. §§ 1533(f), 1536, & 1538. T he Secretary of the Interior or of Commerce, as applicable, may decline to develop and implement a recovery plan only upon finding “that such a plan will not promote the conservation of the species.” Id. § 1533(f)(1). 5 Id. § 1533(a) & (c). 6 T hough the term “delist” does not appear in the Endangered Species Act of 1973 (ESA or the Act), it is generally used by the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Services (together, the Services) to refer to removing a species from the list of endangered or threatened species. 7 Id. 8 Id. § 1533(a); 5 U.S.C. § 553. 9 See, e.g., Defenders of Wildlife v. Sec’y, U.S. Dep’t of the Interior, 354 F. Supp. 2d 1156 (D. Ore. 2005); Nat’l Wildlife Fed’n v. Norton, 386 F. Supp. 2d 553 (D. Vt. 2005). 10 See, e.g., Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7, 21 (D.D.C. 2008). 11 Endangered Species, 32 Fed. Reg. 4001, 4001 (Mar. 11, 1967). 12 See infra “History of Listing and Delisting the Gray Wolf” section. 13 Id. Congressional Research Service 1 link to page 7 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Listing and Delisting Species Under the Endangered Species Act

The ESA aims to accomplish its goal of conserving fish, wildlife, and plants species threatened with extinction by "listing" “listing” species the Services determine to be endangered or threatened.¹⁴ The ESA'14 The ESA’s provisions and protections generallygeneral y apply only to these listed species.¹⁵15 The Act'’s legal framework determines when and how species are listed, reclassified,¹⁶16 and delisted.¹⁷17 The Secretary of the Interior and the Secretary of Commerce (this report refers to "“the Secretary"” to mean either the Secretary of the Interior or the Secretary of Commerce, as applicable) review species'species’ statuses under the Act on theirthe respective Secretary’s own initiative or in response to petitions.¹⁸ Any person¹⁹ petitions.18 Any person19 may petition the Secretary to list, reclassify, or delist a species.²⁰20 The ESA prescribes when and how the Secretary is required to respond to such petitions, as shown in Figure 1. 14 16 U.S.C. §§ 1531(b), 1533(a) & (c). 15 Candidate species being considered for listing receive some minimal protections under the Act before they are listed. 50 C.F.R. § 424.02. 16 Reclassification, as used in this report, refers to a “change[] in status” from endangered to threatened or from threatened to endangered. See 16 U.S.C. § 1533(c)(2)(B). 17 See generally id. § 1533. 18 Id. § 1533(b). 19 Under the ESA, “ person” is defined to mean “ an individual, corporation, partnership, trust, association, or any other private entity; or any officer, employee, agent, department, or instrumentality of the Federal Government, of any State, municipality, or political subdivision of a State, or of any foreign government; any State, municipality, or political subdivision of a State; or any other entity subject to the jurisdiction of the United States. ” Id. § 1532(13). 20 Id. § 1533(b)(3); 5 U.S.C. § 553(e). Congressional Research Service 2 link to page 8 link to page 8 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges

Figure 1. Petitioning the Secretary Under the Endangered Species Act

Source: Congressional Research Service (based on 16 U.S.C. § 1533(b)). Note: "“The Secretary"” refers to the Secretary of the Interior or the Secretary of Commerce, as applicable.

A status review, conducted pursuant to a petition that may be warranted or at the Secretary's ’s initiative, determines whether a species should be or remain listed.²¹ Figure 2 depicts the general pathway for a species from status review and listing through post-delisting monitoring and management under the ESA framework. A brief explanation of each stage is provided below Figure 2.22 21 16 U.S.C. § 1533(a) & (b)(3)(A). For species listed as endangered or threatened, a status review could determine that the species should be reclassified from endangered to threatened or vice versa, as applicable. Id. § 1533(c). 22 For more information on the ESA, see CRS Report RL31654, The Endangered Species Act: A Primer, by Pervaze A. Sheikh and CRS In Focus IF11241, The Legal Fram ework of the Endangered Species Act (ESA) , by Erin H. Ward. Congressional Research Service 3 link to page 14 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Figure 2.²²

Figure 2. Listing and Delisting Species Under the Endangered Species Act

Source: Congressional Research Service (based on 16 U.S.C. §§ 1532, 1533, 1536 & 1538). Note: "Secretary"“Secretary” refers to either the Secretary of the Interior or the Secretary of Commerce, as applicable.

Listing. As a threshold matter, the Secretary may list only groups of organisms that qualify as a "species"“species” under the ESA,²³23 defined to include subspecies and DPSs.²⁴24 Because the term "species" “species” under the Act has a distinct legal meaning that may differ from its conventional or taxonomic meaning,²⁵ meaning,25 this report uses the term "species"“species” to refer to species as defined by the Act (i.e., including subspecies and DPSs) and the term "“full species"” when referring to a taxonomic 23 16 U.S.C. § 1532(16). 24 Distinct population segments (DPSs) are limited to species of vertebrate fish or wildlife that interbreed when mature. 16 U.S.C. § 1532(16). For more information about how the Services have interpreted and applied this term, see infra “Designating Distinct Population Segments (DPSs) 25 See, e.g., John L. Gittleman, Species, ENCYCLOPAEDIA BRITANNICA (Nov. 6, 2019), https://www.britannica.com/science/species-taxon. Congressional Research Service 4 link to page 8 link to page 8 link to page 8 link to page 8 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges when referring to a taxonomic species. For species eligible for listing, the Secretary examines whether the species qualifies as an endangered species or threatened species, as defined by the Act,²⁶26 because of any of the five factors listed inin Figure 2. The ESA requires the Secretary to make this determination "solely" “solely” based on the "“best scientific and commercial data available."²⁷”27 Based on this evaluation, the Secretary either lists the species as endangered or threatened, as appropriate, or determines the species is ineligible for listing and, if the Secretary conducted the status review pursuant to a petition to list, denies the petition.²⁸28 The Secretary may also determine that a species qualifies as an endangered or threatened species but that the species cannot be listed at the time due to the Services'Services’ priorities and limited resources. In that case, the Secretary may deny a petition as warranted but precluded.²⁹29 The Secretary publishes listing determinations in the Federal Register and the Code of Federal Regulations.³⁰

30 Listed. Once endangered and threatened species are listed, the ESA directs federal agencies to "conserve"“conserve” them and their ecosystems.³¹31 As shown inin Figure 2, the Act provides two types of mechanisms to conserve listed species and facilitate their recovery.³²32 First, as shown in the Protections box of Figure 2, it protects the species by prohibiting certain acts with respect to endangered species; similar prohibitions may also be extended to threatened species.³³33 The Act further protects listed species by requiring federal agencies to consult with the Services when their actions, or actions they approve or fund, could affect listed species—often calledcal ed Section 7 consultations.³⁴34 Through this process, federal agencies assess the potential effects of their actions on any endangered or threatened species and evaluate, as necessary, alternatives that would mitigate the impact.³⁵

35 Second, as shown in the Recovery Tools box inin Figure 2, the ESA provides tools to facilitate the recovery of the species. The Act generallygeneral y requires the Secretary to develop and implement a 26 16 U.S.C. § 1532(6) & (20). 27 Id. § 1533(b). “Best scientific and commercial data” is not defined in the ESA. 28 Id. § 1533(a)-(c). 29 Id. § (b)(3)(B)(iii). 30 Id. § 1533(c)(1); 50 C.F.R. § 17.11-17.12. T he Secretary is also required, “to the maximum extent prudent and determinable,” to designate critical habitat concurrently with listing a species. 16 U.S.C. § 1533(a)(3)(A). Critical habitat designations are also published in the Federal Register and Code of Federal Regulations. Id. § 1533(c)(1); 50 C.F.R. § 17.95. 31 16 U.S.C. § 1531(b). Conserving an endangered or threatened species means the federal agency uses “all methods and procedures which are necessary to bring [the species] to the point at which the measures provided [in the ESA] are no longer necessary.” Id. § 1532(3). 32 T he Services use the term “ recovery” to mean “improvement in the status of listed species to the point at which listing is no longer appropriate under the criteria set out in section 4(a)(1) of the Act.” 50 C.F.R. § 402.02. See also Endangered and T hreatened Wildlife and Plants; Final Rule to Reclassify and Remove the Gray Wolf from the List of Endangered and T hreatened Wildlife in Portions of the Conterminous United States; Establishment of T wo Special Regulations for T hreatened Gray Wolves, 68 Fed. Reg. 15,804, 15,809 (Apr. 1, 2003) (“Essentially, recover and conserve both mean to bring a species to the point at which it no longer needs th e protections of the Act, because the species is no longer threatened or endangered.”). 33 16 U.S.C. § 1538(a) & 1533(d). T he Act requires the Secretary to issue regulations, often called 4(d) rules, for threatened species “as he deems necessary and advisable to provide for the conservation of such species.” Id. § 1533(d). In those regulations, the Secretary may prohibit any act that is prohibited with respect to endangered species, with minor limitations. Id. 34 Id. § 1536(a)(2). T his consultation, often called a Section 7 consultation, is intended to ensure that federal agency actions are “not likely to jeopardize the continued existence of endangered or threatened species” or to “adversely modify” or to destroy critical habitat. Id. § 1536; 50 C.F.R. Part 402. 35 16 U.S.C. § 1536; 50 C.F.R. Part 402. Congressional Research Service 5 link to page 8 link to page 8 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges requires the Secretary to develop and implement a recovery plan for each listed species unless such a plan would "“not promote the conservation of the species."³⁶”36 The recovery plan includes any site-specific management actions needed to conserve the species, objective and measureable criteria that would merit delisting the species if met,³⁷37 and estimates of timelines and costs.³⁸38 In addition to recovery plans, Congress amended the ESA in 1982 to allowal ow the Services to reintroduce experimental populations of listed species, which are regulated as threatened species regardless of the listed species'’ status.³⁹39 Experimental populations must be "“wholly separate geographically"geographical y” from existing natural populations of the species.⁴⁰

species.40 As shown in the Review Status box inin Figure 2, the Secretary must review the status of a listed species every five years⁴¹years41—or pursuant to a petition to reclassify or delist the species that may be warranted⁴²warranted42—to determine whether it still stil qualifies as an endangered or threatened species. Species are reclassified or delisted based on the same criteria used to list species, as shown in the Status box inin Figure 2.⁴³

Post-delistingPost-delisting. Once a species is delisted, the states in which the species resides resume control over management of the recovered species.⁴⁴44 The Secretary and the states monitor the status of a recovered species for at least five years after delisting.⁴⁵45 In this period, if the Secretary determines that there is a significant risk to the wellwel -being of the species, the Secretary must exercise emergency powers to restore the Act'’s protections to the species for 240 days, during which time the Secretary may begin rulemaking proceedings to relist the species.⁴⁶

46 Administrative Law and Statutory Interpretation

The Services list, reclassify, and delist species through the rulemaking process. The principles of administrative law and statutory interpretation that generallygeneral y govern the agency rulemaking process and judicial review underpin the Services'’ actions under the ESA.⁴⁷47 Agencies use rules, 36 16 U.S.C. § 1533(f). 37 Species are not automatically delisted if they meet the objective, measurable criteria in their recovery plans. T he Secretary must undertake agency rulemaking to delist the species in accordance with the ESA listing criteria, 5 U.S.C. § 553; 16 U.S.C. § 1533(a), and circumstances may have changed since the criteria were set. 38 16 U.S.C. § 1533(f). For example, the recovery plan may specify the number of breeding p airs that must be sustained for a certain number of years in a particular geographic area to consider the species recovered. See, e.g., Northern Rocky Mountain Wolf Recovery Plan, U.S. FISH & WILDLIFE SERV., at v (1987). 39 Endangered Species Act Amendments, Pub. L. No. 97-304, 96 Stat. 1411 (1982) (codified at 16 U.S.C. § 1539(j)); 16 U.S.C. § 1539(j)(2)(C). A court, reviewing relevant legislative history, concluded that Congress added this option, with its greater regulatory flexibility, to address the Services’ frustration with political opposition to such reintroduction efforts borne from “industry’s fears experimental populations would halt development projects.” Wyo. Farm Bureau Fed’n v. Babbitt, 199 F.3d 1224, 1231-32 (10th Cir. 2000) (citing H.R. Rep. No. 97-567, at 8 (1982)). 40 16 U.S.C. § 1539(j)(1). 41 Id. § 1533(c)(2)(A). 42 Id. § 1533(b). 43 Id. § 1533(c). 44 T he Secretary generally reviews and may need to approve state management plans for states where a recovered species is found as part of the recovery criteria and five-factor threats assessment before finalizing the delisting rule. See, e.g., Endangered and T hreatened Wildlife and Plants; Final Rule Designating the Northern Rocky Mountain Population of Gray Wolf as a Distinct Population Segment and Removing this Distinct Population Segment from the Federal List of Endangered and T hreatened Wildlife, 73 Fed. Reg. 10,514, 10,546-52 (Feb. 27, 2008). 45 16 U.S.C. § 1533(g)(1). 46 Id. §§ 1533(b)(7) & (g)(2). 47 For in-depth information on agency rulemaking, judicial review, and statutory interpretation, see CRS Report Congressional Research Service 6 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Agencies use rules, among other tools, to implement and interpret statutes and promulgate regulations.⁴⁸48 The Administrative Procedure Act (APA)⁴⁹ generally49 general y governs agency rulemaking by prescribing procedural requirements for agencies to follow and providing an opportunity for judicial review of final agency actions.⁵⁰50 The APA requires agencies to publish a proposed rule to provide notice of the agency'’s proposed action and provide an opportunity for public comment, then to publish a final rule that concisely states the agency'’s basis and purpose for the rule.⁵¹51 The agency's ’s statement must generallygeneral y address significant comments and explain the agency'’s rationale for those comments not incorporated into the final rule.⁵²52 Any changes in the final rule must be a " “logical outgrowth"” of the proposed rule to comport with due process.⁵³

53 Parties affected by an agency rule can generallygeneral y seek judicial review of the agency'’s action.⁵⁴54 To the extent the rule relies on an agency'’s interpretation of a provision in a statute it administers, the court generallygeneral y evaluates the agency'’s interpretation under the Chevron doctrine.⁵⁵55 Under the Chevron doctrine,⁵⁶56 the court first determines whether the statutory provision is ambiguous (i.e., if there are multiple permissible meanings) by relying on principles of statutory interpretation.⁵⁷ 57 The court may look to the plain meaning of the term in common parlance, the provision's ’s statutory context, how the term is used elsewhere in the statute or other statutes, the statute's ’s purpose and legislative history, and whether a particular interpretation would render a term superfluous, lead to absurd results, or raise constitutional questions.⁵⁸58 If the court determines that a statutory provision is ambiguous, then it defers to the administering agency'’s interpretation so long as it is a permissible (i.e., reasonable) interpretation.⁵⁹

Under the APA, a court must set aside agency rules if it finds the rule is "59 R41546, A Brief Overview of Rulem aking and Judicial Review, by T odd Garvey, and CRS Report R45153, Statutory Interpretation: Theories, Tools, and Trends, by Valerie C. Brannon. 48 5 U.S.C. § 551(4). 49 Id. §§ 551-559, 701-706. 50 Id. 51 Id. § 553. Congress may provide by statute that all or part of the Administrative Procedure Act (APA) does not apply to certain agency actions. In some cases, Congress has provided alternative rulemaking procedures for an agency to follow. See, e.g., 42 U.S.C. 7607(d) (prescribing rulemaking procedures for the U.S. Environmental Protection Agency to follow for rules promulgated under certain provisions of the Clean Air Act). 52 See, e.g., Perez v. Mortg. Bankers Ass’n, 135 S. Ct. 1199, 1203 (2015). 53 Envt’l Integrity Project v. EPA, 425 F.3d 992, 996 (D.C. Cir. 2005) (“[A]n agency’s proposed rule and its final rule may differ only insofar as the latter is a ‘logical outgrowth’ of the former.”). A final rule is a “logical out growth” of the proposed rule if parties “‘should have anticipated’ that the change was possible, and thus reasonably should have filed their comments on the subject during the notice-and-comment period.” Northeast Md. Waste Disposal Auth. v. EPA, 358 F.3d 936, 952 (D.C. Cir. 2004). 54 5 U.S.C. § 702. Judicial review is a right created by statute under the APA, but Congress may and has limited the availability of judicial review for certain agency actions or entirely precluded judicial review. See, e.g., 38 U.S.C. § 511(a); 42 U.S.C. § 7607(b). 55 See, e.g., Adams Fruit Co. v. Barrett, 494 U.S. 638, 649 (1990). 56 Chevron U.S.A., Inc. v. Natural Res. Def. Council, 467 U.S. 837, 843 (1984). For more information on the Chevron doctrine, see CRS Report R44954, Chevron Deference: A Prim er, by Valerie C. Brannon and Jared P. Cole. 57 Chevron U.S.A., Inc., 467 U.S. at 842. 58 See, e.g., NLRB v. SW Gen., Inc., 137 S. Ct. 929, 938-39 (2017); McDonnell v. United States, 136 S. Ct. 2355, 2369 (2016); Yates v. United States, 135 S. Ct. 1074, 1080 (2015) ; FAA v. Cooper, 566 U.S. 284, 291 -92 (2012); FCC v. AT &T Inc., 562 U.S. 397, 407-08 (2011); Stenberg v. Carhart, 530 U.S. 914, 942 (2000); City of Chicago v. Envtl. Def. Fund, 511 U.S. 328, 337-38 (1994); Anita S. Krishnakumar, Statutory Interpretation in the Roberts Court’s First Era: An Em pirical and Doctrinal Analysis, 62 HASTINGS L.J. 221, 251 (2010). 59 Chevron U.S.A., Inc., 467 U.S. at 843. Congressional Research Service 7 link to page 6 link to page 27 link to page 46 link to page 46 link to page 29 link to page 29 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Under the APA, a court must set aside agency rules if it finds the rule is “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law."⁶⁰”60 For example, a court may determine that a rule is arbitrary and capricious because the agency'’s interpretation of an ambiguous term is not a permissible one.⁶¹61 A court may also hold that an agency rule is arbitrary and capricious if it is illogically il ogical y reasoned, fails to consider an important aspect of the problem, or is unsupported by the administrative record.⁶²62 When a court overturns an agency rule, it generally general y vacates the rule and remands it to the agency.⁶³

63 History of Listing and Delisting the Gray Wolf

• The gray wolf has a long history as a listed species under the ESA and its predecessors. As discussed in this section, from the initial listing to the present, nearly every element of the listing and delisting legal framework has been implicated in regulating the gray wolf under the Act. (See "“Listing and Delisting Species Under the Endangered Species Act" section” section.) Table 1 includes a timeline of legislative, regulatory, and litigation actions by population, andand Table A-1 in thein the Appendix provides a more detailed version. The substantive issues that have been raised in the various rulemakings and court opinions described in this section are discussed by topic in the "Challenges“Chal enges When Listing and Delisting Species”" section.

The gray wolf's traits and history inform much of FWS' 60 5 U.S.C. § 706(2)(A). 61 See, e.g., Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207, 1224 -26 (D. Mont. 2010). Cf. Sec’y of Labor, Mine Safety & Health Admin v. Nat’l Cement Co. of Cal., Inc., 494 F.3d 1066, 1074 -75 (D.C. Cir. 2007). 62 See, e.g., Ctr. for Biological Diversit y v. U.S. Bureau of Land Mgmt., 698 F.3d 1101, 1124 (9th Cir. 2012); Am. Fed’n of Gov’t Emps., Local 2924 v. Fed. Labor Relations Auth., 470 F.3d 375, 380 (D.C. Cir. 2006); United States v. Dierckman, 201 F.3d 915, 926 (7th Cir. 2000) (quoting Bagdonas v. Dep’t of the T reasury, 93 F.3d 422, 426 (7th Cir. 1996)); Allied-Signal, Inc. v. Nuclear Reg. Comm’n, 988 F.2d 146, 152 (D.C. Cir. 1993). 63 See, e.g., Humane Soc’y of U.S. v. Kempthorne, 579 F. Supp. 2d 7, 21 (D.D.C. 2008). Congressional Research Service 8 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges The gray wolf’s traits and history inform much of FWS’s analysis of threats to the species and pathways to recovery. Gray wolves are the largest member of the Canidae (i.e., dog) family.⁶⁴ 64 They are frequently found in packs and occupy defined territory, but lone gray wolves may leave their packs to join another pack or wander alone.⁶⁵65 Gray wolves are effective and adaptive predators who generallygeneral y hunt large prey, such as moose, elk, caribou, bison, and deer; they also have been known to eat smaller prey.⁶⁶ Historicallyeat smal er prey.66 Historical y, gray wolves ranged throughout most of North America, Europe, and Asia.⁶⁷67 On the North American continent, gray wolves were once found from Canada and Alaska to northern Mexico except for much of the southeastern United States (where the related but distinct red wolf lived) and parts of southern California.⁶⁸68 The arrival of European settlers and their expansion into the western frontier led to widespread persecution of wolves as a result of fear, superstition, and perceived and real conflicts between wolves and humans, such as attacks on humans, domestic animals, or livestock.⁶⁹69 Encouraged by federal, state, and local bounties, settlers poisoned, trapped, and shot wolves until they were eliminated from more than 95% of their historical range.⁷⁰

70 Listing and Recovery Efforts

FWS listed the first gray wolf subspecies, the eastern timber wolf (C. lupus lycaon), as endangered in 1967 under the Endangered Species Preservation Act of 1966 (ESPA).⁷¹71 After the Endangered Species Conservation Act of 1969 (ESCA)⁷²72 amended the ESPA, FWS listed the northern Rocky Mountain wolf (C. lupus irremotus) as endangered in 1973.⁷³73 Under the ESPA and the ESCA, the Services could list only species or subspecies that were endangered worldwide.⁷⁴74 Enacted in 1973,⁷⁵75 the ESA allowedal owed the Services to identify a species as endangered or threatened in all al or a significant part of its range.⁷⁶76 After the ESA was enacted, FWS listed two more gray wolf subspecies—the Mexican wolf (C. lupus baileyi) and the Texas wolf (C. lupus monstrabilis)—as endangered in 1976.⁷⁷77 In 1978, FWS combined these listings into one listing for the gray wolf species as endangered throughout the lower 48 states except Minnesota and a separate listing for the gray wolf in Minnesota as threatened.⁷⁸

78 64 Endangered and T hreatened Wildlife and Plants; Proposal to Reclassify and Remove the Gray Wolf from the List of Endangered and T hreatened Wildlife in Portions of the Conterminous United States; Proposal to Establish T hree Special Regulations for T hreatened Gray Wolves, 65 Fed. Reg. 43 ,450, 43,451 (July 13, 2000). 65 Id. 66 Id. 67 Id. 68 Id. 69 Id. 70 Id. 71 32 Fed. Reg. 4001 (Mar. 11, 1967). 72 Pub. L. No. 91-135, 83 Stat. 273 (1969). 73 Amendments to Lists of Endangered Fish and Wildlife, 38 Fed. Reg. 14,678 (June 4, 1973). 74 Pub. L. No. 89-669, 80 Stat. 926 (1966); Pub. L. No. 91-135, 83 Stat. 273 (1969). 75 Pub. L. No. 93-205, 87 Stat. 884 (1973) (codified at 16 U.S.C. §§ 1531 – 1544). 76 16 U.S.C. § 1533(a). 77 Determination That T wo Species of Butterflies Are T hreatened Species and T wo Species of Mammals are Endangered Species, 41 Fed. Reg. 17,736 (Apr. 28, 1976); Endangered Status for 159 T axa of Animals, 41 Fed. Reg. 24,064 (June 14, 1976). 78 Reclassification of the Gray Wolf in the United States and Mexico, with Determination of Critical Habitat in Michigan and Minnesota, 42 Fed. Reg. 9607 (Mar. 9, 1978). Congressional Research Service 9 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Between 1978 and 1982, FWS created recovery plans for the eastern timber wolf, the northern Rocky Mountain wolf, and the Mexican wolf that outlined management strategies and recovery criteria.⁷⁹79 It later updated each of those plans.⁸⁰80 In the 1990s, FWS reintroduced gray wolves into central Idaho and the greater YellowstoneYel owstone area in the northern Rocky Mountains and the Southwest.⁸¹81 FWS designated each population as a nonessential experimental population, meaning FWS determined the population is not essential to the conservation of the species.⁸² 82 Protected from human-caused mortality, which FWS identified as the greatest threat to the species, gray wolf populations in the western Great Lakes region, the northern Rocky Mountains, and the Southwest increased and expanded their ranges.⁸³

83 Designating Distinct Population Segments (DPSs)

The term DPS is distinct to the ESA, unlike species and subspecies, which are commonly used taxonomic terms with scientific meanings.⁸⁴ Including DPSs in the Act's definition of species has been particularly relevant to gray wolf listing and delisting rules. Because the term DPS is not defined in the ESA, the Beginning in the early 2000s, FWS promulgated a series of rules that simultaneously designated gray wolf DPSs, removing them from (or dividing up) the previously listed gray wolf entities, and reclassified or delisted them—nearly al of which have been overturned by courts. As mentioned above, the ESA defines species to include taxonomic species, subspecies, and DPSs.84 The term DPS is distinct to the ESA, unlike species and subspecies, which are commonly used taxonomic terms with scientific meanings.85 The term DPS is not defined in the ESA. The Services issued a DPS policy (DPS Policy) in 1996 explaining how they would interpret and apply the term.⁸⁵ 86 Under the DPS Policy, the Services evaluate the population's discreteness⁸⁶ and significance⁸⁷ to ’s discreteness87 and significance88 to determine if it qualifies as a DPS and, therefore, a listable species under the Act.⁸⁸

89 FWS has used 79 Recovery Plan for the Eastern Timber Wolf, EASTERN T IMBER WOLF RECOVERY TEAM (1978); Northern Rocky Mountain Wolf Recovery Plan, U.S. FISH & WILDLIFE SERV. (1980); Mexican Wolf Recovery Plan, U.S. FISH & WILDLIFE SERV. (1982). 80 Northern Rocky Mountain Wolf Recovery Plan, U.S. FISH & WILDLIFE SERV. (1987); Recovery Plan for the Eastern Tim ber Wolf, EASTERN T IMBER WOLF RECOVERY TEAM (Rev. 1992); Mexican Wolf Recovery Plan: First Revision, U.S. FISH & WILDLIFE SERV. (2017). 81 Endangered and T hreatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Gray Wolves in Yellowstone National Park in Wyoming, Idaho, and Montana, 59 Fed. Reg. 60,252, 60,252 (Nov. 22, 1994); Endangered and T hreatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Gray Wolves in Central Idaho and Southwestern Montana, 59 Fed. Reg. 60,266, 60,266 (Nov. 22, 1994); Endangered and T hreatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of the Mexican Gray Wolf in Arizona and New Mexico, 63 Fed. Reg. 1752, 1752 (Jan. 12, 1998). 82 59 Fed. Reg. at 60,252; 59 Fed. Reg. at 60,266; 63 Fed. Reg. at 1752. 83 See, e.g., Endangered and T hreatened Wildlife and Plants; Final Rule Designating the Western Great Lakes Populations of Gray Wolves as a Distinct Population Segment; Removing the West ern Great Lakes Distinct Population Segment of the Gray Wolf from the List of Endangered and T hreatened Wildlife, 72 Fed. Reg. 6052, 6053 -56 (Feb. 8, 2007); 73 Fed. Reg. 10,514, 10523 -26 (Feb. 27, 2008). 84 16 U.S.C. § 1532(16). 85 See Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act, 61 Fed. Reg. 4722, 4722 (Feb. 7, 1996) (henceforth “ DPS Policy”); 16 U.S.C. § 1532. 86 DPS Policy, 61 Fed. Reg. 4722. 87 T he DPS Policy considers a population discrete if it is “markedly separate from other populations” of the same species due to “ physical, physiological, ecological, or behavioral factors.” Id. at 4725. A population may also be considered discrete if (1) it is separated from other populations by international governmental boundaries and (2) the legal protections differ significantly between the two countries. Id. 88 T he DPS Policy considers a population significant based on its biological and ecological significance to the species. Id. For example, a population might be significant if it persists in an unusual or unique setting for the species, its loss would create a significant gap in the species’ range, it represents the only surviving population in the wild that was not reintroduced, or its genetic composition differs markedly from other populations of the species. Id. 89 Id. at 4725. Congressional Research Service 10 link to page 27 link to page 16 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges its authority to list DPSs as species, as interpreted by the Services’ DPS policy, to designate gray wolf populations as DPSs and delist those DPSs. The various rules designating and delisting gray wolf DPSs and related court decisions are described below and listed in Table 1. Final Rule Designating Eastern, Western, and Southwestern DPSs in 2003 Final Rule Designating Eastern, Western, and Southwestern DPSs in 2003

In 2000, FWS proposed to designate four DPSs of gray wolves—the Western Great Lakes DPS, Western DPS, Southwestern DPS, and Northeastern DPS,⁸⁹90 as shown in Map 2 of Figure 3—and to delist the gray wolf in any state outside the range of those DPSs.⁹⁰91 FWS determined that non-DPS states were outside the gray wolf'’s current range and unlikely to be repopulated by gray wolves, and that wolf restoration to those areas was neither potentiallypotential y feasible nor necessary for recovery.⁹¹92 FWS also proposed to reclassify the gray wolves of the Western Great Lakes DPS, Western DPS, and Northeastern DPS from endangered to threatened.⁹²93 For the Western Great Lakes and Western DPSs, FWS determined that they were not in danger of extinction based on the recovery progress of the western Great Lakes and northern Rocky Mountain gray wolf populations, respectively.⁹³94 FWS determined that these populations were sufficient to ensure the continuing viability of the DPSs as a whole.⁹⁴95 For the Northeastern DPS, FWS proposed to reclassify it as threatened due to the regulatory flexibility afforded by a threatened status, rather than based on determining that the DPS met the definition of "“threatened species.”96 90 Endangered and T hreatened Wildlife and Plants; Proposal to Reclassify and Remove the Gray Wolf from the List of Endangered and T hreatened Wildlife in Portions of the Conterminous United States; Proposal to Establish T hree Special Regulations for T hreatened Gray Wolves, 65 Fed. Reg. 43,450, 43,450, 43,472-74, 43,476-78 (July 13, 2000). Under the proposal, the Western Great Lakes DPS would include gray wolves in North Dakota, South Dakota, Minnesota, Wisconsin, and Michigan; the Western DPS would include gray wolves in Washington, Oregon, Idaho, Montana, Wyoming, Utah, Colorado, and northern parts of Arizona and New Mexico; the Southwestern D PS would include gray wolves in southern Arizona and New Mexico, parts of southwest T exas, and Mexico; and the Northeastern DPS would include gray wolves in New York, Vermont, New Hampshire, and Maine. Id. at 43,473. 91 Id. at 43,450, 43,476-78. 92 Id. 93 Id. at 43,450, 43,472-74, 43,476-78. 94 Id. 95 Id. 96 Id. T hough FWS provided this justification in its proposed rule, a species’ status is determined by whether it meets the definition of endangered or threatened based on the five statutory factors. 16 U.S.C. § 1533(a). Congressional Research Service 11 link to page 16 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Figure 3. Distinct Population Segments (DPSs) in 2000 Proposed Rule and 2003 Final Rule Designations and Listing Statuses Source: U.S. Fish and Wildlife Service. The gray wolf has never been listed in Alaska or Hawai . threatened species."⁹⁵

Figure 3. Distinct Population Segments (DPSs) in 2000 Proposed Rule and 2003 Final Rule Designations and Listing Statuses

Source: U.S. Fish and Wildlife Service.

In the 2003 final rule, FWS combined and expanded the Western Great Lakes and Northeastern DPSs to create the Eastern DPS, as shown in Map 3 of Figure 3, after not finding justification for a separate Northeastern DPS.⁹⁶97 FWS reclassified the gray wolves of the Eastern DPS and the Western DPS from endangered to threatened.⁹⁷98 The agency also determined that it could delist only based on a finding of recovery, extinction, or original listing in error.⁹⁸ Accordingly, FWS 99 Accordingly, FWS 97 68 Fed. Reg. 15,804, 15,859 (Apr. 1, 2003). FWS had relied on anecdotal evidence of wolf sightings when it proposed to designate the Northeastern DPS and expected to receive more information on wolf populations in that region during the comment period. 65 Fed. Reg. at 43,450. However, FWS received no new data on this subject, so it determined that it could not designate a DPS without concrete evidence of a population. 68 Fed. Reg. at 15,859. 98 Id. at 15,809-11. 99 Id. at 15,826, 15,859. Congressional Research Service 12 link to page 18 link to page 20 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges extended the three DPSs to include 12 of the states it had proposed to delist.100extended the three DPSs to include 12 of the states it had proposed to delist.⁹⁹ The agency delisted the gray wolf only in 14 states in the southeastern United States and in portions of Oklahoma and Texas that FWS determined were outside the gray wolf'’s historical range.¹⁰⁰

101 District courts in Oregon and Vermont ultimately vacated the 2003 final rule.¹⁰¹102 Those courts held that FWS conflated the statutory terms "all"“al ” and "“a significant portion"” when analyzing whether the DPSs were endangered or threatened in "all “al or a significant portion of [their] range."¹⁰²”103 By assessing what constituted "“a significant portion"” of the range based on which areas ensured the continuing viability of the DPS as a whole, FWS rendered the phrase "“a significant portion" ” superfluous by ensuring that any DPS endangered or threatened in "“a significant portion"” of its range would also be endangered or threatened in "all" “al ” of its range.¹⁰³104 Those courts also concluded that FWS violated the ESA and the DPS Policy by designating DPSs based on geographical rather than biological criteria and by failing to conduct the five-factor analysis for wolves outside the core recovery populations, thus reclassifying species without applying the statutory criteria.¹⁰⁴ 105 The Oregon district court further held that FWS combining the two DPSs and including states in the DPSs beyond the recovered populations'’ ranges was arbitrary and capricious because the gray wolf'wolf’s conservation status varied across each DPS.¹⁰⁵106 By extending the DPSs to the gray wolf's ’s historical range rather than "“draw[ing] a line around a population whose conservation status differs from other populations within that species,"” the court held that FWS "“invert[ed]"” the DPS'DPS’s purpose.¹⁰⁶ Finally, the107 The Vermont district court held that FWS violated the APA by combining the Western Great Lakes and Northeastern DPSs into a new Eastern DPS in the 2003 final rule, which did not appear in the proposed rule.¹⁰⁷108 The Vermont district court determined that establishing the Eastern DPS was not a "“logical outgrowth"” of the proposed rule and accordingly did not provide the public with adequate notice and opportunity for comment.¹⁰⁸

109 Final Rules Designating and Delisting Western Great Lakes DPS in 2007 and Northern Rocky Mountain DPS in 2008

After the district courts vacated the 2003 final rule, FWS adjusted its approach by individually individual y designating and delisting the Western Great Lakes DPS (as shown inin Figure 4) in 2007 and the Northern Rocky Mountain DPS (as shown inin Figure 5) in 2008.¹⁰⁹110 For these and later DPS rules, FWS assessed whether each DPS met the DPS Policy'’s discreteness and significance criteria.¹¹⁰ 111 100 Id. 101 Id. 102 Defenders of Wildlife v. Sec’y, U.S. Dep’t of the Interior, 354 F. Supp. 2d 1156 (D. Ore. 2005); Nat’l Wildlife Fed’n v. Norton, 386 F. Supp. 2d 553 (D. Vt. 2005). 103 Defenders of Wildlife, 354 F. Supp. 2d at 1167-69; Nat’l Wildlife Fed’n, 386 F. Supp. 2d at 565-66. 104 Defenders of Wildlife, 354 F. Supp. 2d at 1167-69; Nat’l Wildlife Fed’n, 386 F. Supp. 2d at 565-66. 105 Defenders of Wildlife, 354 F. Supp. 2d at 1171; Nat’l Wildlife Fed’n, 386 F. Supp. 2d at 563-65. 106 Defenders of Wildlife, 354 F. Supp. 2d at 1170. 107 Id. 108 Nat’l Wildlife Fed’n, 386 F. Supp. 2d at 564-65. 109 Id. 110 72 Fed. Reg. 6052, 6052 (Feb. 8, 2007); 73 Fed. Reg. 10,514, 10,514 (Feb. 27, 2008). 111 See, e.g., 72 Fed. Reg. at 6059-60; 73 Fed. Reg. at 10,519-20; Endangered and T hreatened Wildlife and Plants; Final Rule to Identify the Western Great Lakes Populations of Gray Wolves as a Distinct Population Segment and to Revise the List of Endangered and T hreatened Wildlife, 74 Fed. Reg. 15,070, 15,078 (Apr. 2, 2009); Endangered and T hreatened Wildlife and Plants; Final Rule to Identify the Northern Rocky Mountain Population of Gray Wolf as a Distinct Population Segment and to Revise the List of Endangered and T h reatened Wildlife, 74 Fed. Reg. 15,123, Congressional Research Service 13 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges FWS determined that gray wolf populations were discrete under the DPS Policy by comparing the distance between areas occupied by gray wolf populations to gray wolf dispersal data, finding that the populations were separated by more than three times the average dispersal distance and that the area in between generallygeneral y was not suitable habitat for gray wolves.¹¹¹112 In the new final rules, FWS determined the populations to be significant under the DPS Policy by finding that (1)  the populations occupied an unusual or unique ecological setting for the gray wolf, and (2) (2) losing these populations would create a significant gap in the gray wolf'’s range.¹¹²113 In subsequent DPS rules, FWS would rely solely on the latter finding.¹¹³

114 Figure 4. Western Great Lakes Distinct Population Segment

Source: U.S. Fish and Wildlife Service.

Source: U.S. Fish and Wildlife Service. 15,128-29 (Apr. 2, 2009). FWS analyzed discreteness and significance under the DPS Policy for the 2003 rule, but its discussion was less robust than the analysis found in the DPS rules from 2007 onward. See 68 Fed. Reg. at 15,818-19. 112 See, e.g., 72 Fed. Reg. at 6059; 73 Fed. Reg. at 10,519-20; 74 Fed. Reg. at 15,078; 74 Fed. Reg. at 15,128-29. 113 72 Fed. Reg. at 6059-60; 73 Fed. Reg. at 10,520. 114 See, e.g., 74 Fed. Reg. at 15,079; 74 Fed. Reg. at 15,129. Congressional Research Service 14 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges In its 2007 and 2008 rulemakings, FWS also assessed whether each population had met the recovery criteria in its recovery plan and was no longer in danger of extinction at the time or in the foreseeable future.¹¹⁴115 FWS found that both the Western Great Lakes and Northern Rocky Mountain populations had met the objective criteria laid out in the recovery plans.¹¹⁵116 It also determined that the States of Minnesota, Michigan, and Wisconsin in the Western Great Lakes DPS and the States of Montana and Idaho in the Northern Rocky Mountain DPS had adequate wolf management plans in place.¹¹⁶117 However, in the proposed rule for the Northern Rocky Mountain DPS, FWS determined that Wyoming'’s wolf management plan was inadequate to ensure the continued recovery of the species.¹¹⁷118 Among other concerns, FWS pointed to Wyoming committing to manage only seven breeding packs outside the national parks¹¹⁸parks119 and to Wyoming designating the gray wolf as a predatory animal in most of the state.¹¹⁹120 FWS stated that delisting was contingent on Wyoming implementing an adequate wolf management plan.¹²⁰121 Wyoming enacted legislation in February 2007 removing statutory obstacles to the revisions FWS required, and the Wyoming Fish and Game Commission approved the revised plan in November 2007.¹²¹ 122 In the 2008 final rule, FWS determined that Wyoming'’s plan would adequately ensure the continued recovery of the gray wolf population there.¹²²

Figure 5. Northern Rocky Mountain Distinct Population Segment

Source: U.S. Fish and Wildlife Service.

123 115 72 Fed. Reg. 6052, 6052 (Feb. 8, 2007); 73 Fed. Reg. 10,514, 10,514 (Feb. 27, 2008). 116 72 Fed. Reg. at 6052-56; 73 Fed. Reg. at 10,520-26. 117 72 Fed. Reg. at 6083-95; 73 Fed. Reg. at 10,546-49. 118 72 Fed. Reg. at 6134. 119 T he recovery criteria in the Northern Rocky Mountain Wolf Recovery Plan established 10 breeding pairs in each of the 3 recovery areas—northern Montana, central Idaho, and the greater Yellowstone area— as a minimum recovery level. Northern Rocky Mountain Wolf Recovery Plan , U.S. FISH & WILDLIFE SERV., at 10 (1987). To ensure the populations’ continued recovery, FWS determined that each state (Montana, Idaho, and Wyoming) should commit to managing their populations to maintain at least 15 breeding pairs. See, e.g., 73 Fed. Reg. at 10,522; Endangered and T hreatened Wildlife and Plants; Removal of the Gray Wolf in Wyoming from the Federal List of Endangered and T hreatened Wildlife and Removal of the Wyoming Wolf Population’s Status as an Experimental Population, 77 Fed. Reg. 55,530, 55,538 (Sept. 10, 2012). Wyoming’s gray wolf population was differently situated from the other two states because most of the gray wolves in the greater Yellowstone area occupy land within the boundaries of national parks, such as Yellowstone National Park. Id. 120 According to FWS, classifying the wolf as a “predatory animal” under Wyoming law means the animal is “under the jurisdiction of the Wyoming Department of Agriculture and may be taken by anyone, anywhere in the predatory animal area, at any time, without limit, and by any means[.]” 72 Fed. Reg. at 6129. 121 Id. at 6106. 122 Endangered and T hreatened Wildlife and Plants; Designating the Northern Rocky Mountain Population of Grey Wolf as a Distinct Population Segment and Removing this Distinct Population Segment from the Federal List of Endangered and T hreatened Wildlife, 72 Fed. Reg. 36,939, 36,940 (July 6, 2007). 123 73 Fed. Reg. at 10,514, 10,552-55. Congressional Research Service 15 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Figure 5. Northern Rocky Mountain Distinct Population Segment Source: U.S. Fish and Wildlife Service. Much like the 2003 rule, courts also vacated these final rules.124Much like the 2003 rule, courts also vacated these final rules.¹²³ For the 2007 Western Great Lakes DPS final rule, a federal district court in the District of Columbia held that the ESA was ambiguous about whether FWS could designate for delisting purposes a DPS from a listed full species if FWS had never listed the DPS specifically.¹²⁴specifical y.125 However, FWS had argued that the ESA was unambiguous and the plain meaning of the text supported its authority to designate and delist a DPS from a listed full species.¹²⁵126 Because FWS had relied on the ESA'’s plain language rather than interpreting the text, the court determined there was no FWS interpretation to defer to under the Chevron doctrine.¹²⁶ 124 Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7 (D.D.C. 2008); Defenders of Wildlife v. Hall, No. 9:08-cv-00056 (Oct. 14, 2008) (order vacating and remanding rule to FWS and dismissing case with prejudice). 125 Humane Soc’y of the U.S., 579 F. Supp. 2d at 17. 126 Id. at 19-20. Congressional Research Service 16 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges the Chevron doctrine.127 The court vacated the rule and remanded it to FWS to interpret the ambiguous statutory language.¹²⁷

128 For the 2008 Northern Rocky Mountain DPS final rule, a federal court in Montana reviewed FWS' FWS’s rule when it granted a motion to enjoin the rule while litigation proceeded.¹²⁸129 To issue a preliminary injunction, a court must find, among other things, that the plaintiffs have a likelihood of success on the merits of the case.¹²⁹130 The court determined the plaintiffs were likely to prevail based on two arguments. First, the court determined that FWS likely had been arbitrary and capricious by inadequately explaining why its final rule ignored the recovery plan criterion of genetic exchange between gray wolves from different recovery areas (i.e., central Idaho, northwestern Montana, and the greater YellowstoneYel owstone area).131 area).¹³⁰ Genetic exchange had been included as a recovery criterion in a 1994 environmental impact statement prepared to evaluate the environmental impacts of introducing the experimental gray wolf populations into central Idaho and the greater Yellowstone area.¹³¹Yel owstone area.132 The court held that although FWS did not have to rely on recovery criteria to find that a species had recovered, the agency needed to explain its decision to ignore such criteria adequately.¹³²133 Second, the court determined that FWS was arbitrary and capricious in approving Wyoming'’s wolf management plan—part of the recovery criteria—because, in the court'’s view, FWS'’s reasons for rejecting previous Wyoming plans applied equallyequal y to the 2007 one.¹³³134 After issuing the preliminary injunction, the court granted FWS's ’s request to vacate the rule and remand it.¹³⁴

135 Final Rules Designating and Delisting Western Great Lakes DPS and Northern Rocky Mountain DPS Except Wyoming in 2009

In 2009, FWS again published final rules designating and delisting the Western Great Lakes DPS and the Northern Rocky Mountain DPS, except it did not delist the gray wolf in Wyoming after finding the state'’s management plan inadequate.¹³⁵136 FWS issued the final Western Great Lakes DPS rule, which interpreted FWS'’s authority to designate and delist DPSs from listed species to address the concerns raised by the D.C. district court'’s 2008 ruling, without issuing a new proposed rule.¹³⁶ Parties challenged137 Parties chal enged the latest Western Great Lakes DPS rule for, among other 127 Id. 128 Id. 129 Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160 (D. Mont. 2008). 130 Id. at 1167 (citing Nat’l Wildlife Fed’n v. Nat’l Marine Fisheries Serv., 422 F.3d 782, 795 (9th Cir. 2005)). 131 FWS argued that the criterion did not require evidence of actual genetic exchange, only the potential for likely genetic exchange; the court disagreed. Id. at 1169-70. 132 Id. at 1169-71. 133 Id. 134 Id. at 1172-75. 135 Endangered and T hreatened Wildlife and Plants; Designating the Northern Rocky Mountain Population of Gray Wolf as a Distinct Population Segment and Removing this Distinct Population Segment from the Federal List of Endangered and T hreatened Wildlife, 73 Fed. Reg. 63,926, 63,926 (Oct. 28, 2008); Defenders of Wildlife v. Hall, No. 9:08-cv-00056 (Oct. 14, 2008) (order vacating and remanding rule to FWS and dismissing case with prejudice). 136 74 Fed. Reg. 15,070 (Apr. 2, 2009); 74 Fed. Reg. 15,123 (Apr. 2, 2009 ). 137 74 Fed. Reg. at 15,075-78. Congressional Research Service 17 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges the latest Western Great Lakes DPS rule for, among other things, violating the APA'’s notice and comment requirements.¹³⁷138 Pursuant to a settlement agreement, FWS ultimately withdrew the rule.¹³⁸

139 The Montana district court vacated the 2009 Northern Rocky Mountain DPS rule after concluding that the ESA did not allowal ow FWS to list a partial DPS (i.e., listing the gray wolf only in the Wyoming segment of the DPS).¹³⁹140 FWS had interpreted the statutory phrase "“significant portion of its range"” in the endangered species and threatened species definitions to allowal ow a species to be listed for only that portion of its range where the Services determine the species is endangered or threatened.¹⁴⁰141 The court rejected this interpretation as impermissible under the Act and vacated the rule.¹⁴¹142 It held that the plain language of the ESA precluded listing a smallersmal er classification than a DPS.¹⁴²143 The court also held that FWS'’s interpretation rendered superfluous Congress's ’s addition of DPS to the definition of "species"“species” and Congress'’s restriction of DPSs to vertebrate species because under FWS'’s interpretation, the agency could simply list the full species or subspecies for only the range occupied by the DPS and achieve the same result without the DPS designation and for any species—vertebrate or not.¹⁴³144 However, an act of Congress in 2011 directed FWS to reinstate the 2009 rule designating and delisting the Northern Rocky Mountain DPS without Wyoming.¹⁴⁴

145 Final Rule Designating and Delisting Western Great Lakes DPS in 2011

FWS published another final rule designating and delisting the Western Great Lakes DPS in 2011.¹⁴⁵146 In the proposed rule, FWS also proposed to recognize the eastern timber wolf as a full species (C. lycaon) rather than a subspecies of gray wolf (C. lupus lycaon) based on developments in taxonomic research.¹⁴⁶147 In recognizing the eastern timber wolf as a full species, FWS proposed to delist the gray wolf in all al or part of 29 states (outside the Western Great Lakes DPS) where FWS determined that the areas were part of the historical range of the eastern timber wolf or red wolf (C. rufus) rather than the gray wolf (C. lupus).¹⁴⁷148 In the 2011 Western Great Lakes DPS final rule, however, FWS determined that the scientific community had not reached a consensus on whether the eastern timber wolf was a full species.¹⁴⁸149 FWS accordingly continued to recognize the eastern timber wolf as a subspecies of gray wolf until the scientific debate was 138 Humane Soc’y of the U.S. v. Salazar, No. 1:09-CV-1092 (D.D.C. June 15, 2009) (complaint). 139 Humane Soc’y of the U.S. v. Salazar, No. 1:09-CV-1092 (D.D.C. July 2, 2009) (settlement order). 140 Defenders of Wildlife v. Salazar, 812 F. Supp. 2d 1205, 1207 (D. Mont. 2009). 141 Id. at 1218. 142 Id. at 1221-22. 143 Id. at 1218-24. 144 Id. 145 Department of Defense and Full-Year Appropriations Act, 2011, Pub. L. No. 112-10, § 1713, 125 Stat. 150 (2011). Parties challenged this legislation as unconstitutional for violating the separation -of-powers doctrine. Alliance for the Wild Rockies v. Salazar, 800 F. Supp. 2d 1123 (D. Mont. 2011). A court upheld the legisla tion, holding that Congress substantively amended the ESA and did not direct the federal courts to make specific findings about the rule’s validity under the ESA. Id.; Alliance for the Wild Rockies v. Salazar, 672 F.3d 1170, 1175 (9th Cir. 2012). 146 Endangered and T hreatened Wildlife and Plants; Revising the Listing of the Gray Wolf (Canis lupus) in the Western Great Lakes, 76 Fed. Reg. 81,666 (Dec. 28, 2011). 147 Endangered and T hreatened Wildlife and Plants; Proposed Rule to Revise the List of Endangered and T hreatened Wildlife for the Gray Wolf (Canis lupus) in the Eastern United States, Initiation of Status Reviews for the Gray Wolf and for the Eastern Wolf (Canis lycaon), 76 Fed. Reg. 26,086, 26,088 (May 5, 2011). 148 Id. at 26,086-88. 149 76 Fed. Reg. at 81,669. Congressional Research Service 18 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges recognize the eastern timber wolf as a subspecies of gray wolf until the scientific debate was resolved and postponed delisting in the 29 states and partial states.¹⁴⁹150 FWS otherwise finalized the rule as proposed, relying on data and analysis similar to what it had used in prior rules designating and delisting the Western Great Lakes DPS.¹⁵⁰

151 A district court in the District of Columbia vacated the 2011 Western Great Lakes DPS rule in 2014.¹⁵¹152 The court reviewed FWS'’s interpretation of its statutory authority under the ESA to designate and delist a DPS from a listed full species, which the agency adopted after the 2008 opinion vacating FWS'’s 2007 Western Great Lakes DPS rule that relied on the plain meaning of the ESA.¹⁵²153 On appeal, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) held in 2017 that FWS could designate and delist DPSs from listed full species but that FWS had failed to do so properly in the 2011 rule.¹⁵³154 The court concluded that the 2011 Western Great Lakes DPS rule was arbitrary and capricious because FWS had improperly conducted its analysis by failing to consider two factors: (1) the effect of delisting the DPS on the remainder of the species and (2) the loss of the gray wolf'’s historical range when analyzing threats to the species.¹⁵⁴

species.155 Final Rule Delisting the Gray Wolf in Wyoming in 2012

After approving its revised state laws and wolf management plan, FWS delisted the gray wolf in Wyoming in 2012.¹⁵⁵156 The federal district court in the District of Columbia vacated the rule after finding it was arbitrary and capricious for FWS to rely on nonbinding promises in Wyoming's ’s management plan to determine the state'’s regulatory mechanisms were adequate.¹⁵⁶157 The D.C. Circuit reversed the federal district court, holding that the ESA did not limit FWS to considering only legal y only legally binding regulatory mechanisms to determine whether the regulatory mechanisms were adequate to protect the species.¹⁵⁷158 The rule delisting the gray wolf in Wyoming was accordingly reinstated.¹⁵⁸

Proposals to Delist the Gray Wolf Listed Entities

In 2013 and 2019159 Delisting the Gray Wolf Listed Entities Beginning in 2013, FWS delisting proposals have examined the gray wolf entities that were listed through FWS’s various rulemakings (referred to as the “listed entities”) rather than attempting to list or delist gray wolf DPSs. As discussed in more detail below, in 2013, FWS proposed to delist the gray wolf except for the Mexican wolf subspecies, which FWS listed as endangered in 2015.¹⁵⁹ FWS published the 2013 proposed rule when gray wolves in the Northern Rocky Mountain and Western Great Lakes DPSs were delisted. FWS considered whether the remaining listed entities qualified as "species" under the ESA—thus listable under the Act. Finding they did not qualify, FWS evaluated whether the gray wolf or any subspecies or population of entities (at the time, (1) the gray wolf in Minnesota and (2) the gray wolf in the 150 Id. at 81,666, 81,669. 151 Id. at 81,721-23. 152 Humane Soc’y of the U.S. v. Jewell, 76 F. Supp. 2d 69, 110-13 (D.D.C. 2014). 153 Id. 154 Humane Soc’y of the U.S. v. Zinke, 865 F.3d 585, 600-07 (D.C. Cir. 2017). 155 Id. 156 77 Fed. Reg. 55,530 (Sept. 10, 2012). T he gray wolf in Wyoming is not a species, subspecies, or DPS. However, as discussed above, the 2011 legislation directed FWS to reinstate the rule delisting the gray wolf in the Northern Rocky Mountain DPS, except for in Wyoming, leaving the gray wolf in Wyoming listed. Department of Defense and Full-Year Appropriations Act, 2011, Pub. L. No. 112-10, § 1713, 125 Stat. 150 (2011). In the proposed and final rules, FWS assessed the status and recovery of the gray wolf in Wyoming in the context of being part of the Northern Rocky Mountain DPS. 76 Fed. Reg. 61,782 (Oct. 5, 2011) (proposed rule); 77 Fed. Reg. 55,530 (Sept. 10, 2012) (final rule). 157 Defenders of Wildlife v. Jewell, 68 F. Supp. 3d 193, 203 -10 (D.D.C. 2014). 158 Defenders of Wildlife v. Zinke, 849 F.3d 1077, 1082-84, 1093 (D.C. Cir. 2017). 159 Endangered and T hreatened Wildlife and Plants; Reinst atement of Removal of Federal Protections for Gray Wolves in Wyoming, 82 Fed. Reg. 20,284 (May 1, 2017). Congressional Research Service 19 link to page 27 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges lower 48 states—other than Minnesota, the Northern Rocky Mountain DPS, and the Western Great Lakes DPS—and Mexico) and relist the Mexican wolf (C. lupus baileyi), a subspecies of the gray wolf, as endangered.160 However, FWS finalized the Mexican wolf listing in 2015 as a separate listing without finalizing the delisting component of the proposed rule.161 In that rule, FWS revised the gray wolf listing for the lower 48 states that had previously included the Mexican wolf’s territory in New Mexico and Arizona to exclude that area.162 FWS published a new proposed rule in 2019 to delist the listed entities other than the Mexican wolf.163 At the time, the listed entities were (1) the gray wolf in Minnesota; and (2) the gray wolf in the lower 48 states and Mexico, except for gray wolves in Minnesota, the Northern Rocky Mountain DPS of gray wolves, and the Mexican wolf. In November 2020, FWS published a final rule removing these two gray wolf entities from the list of endangered and threatened species effective January 4, 2021, but leaving the Mexican wolf listed as endangered.164 2013 Proposed Rule to Delist Gray Wolf Listed Entities and List Mexican Wolf In 2013, FWS proposed to delist the gray wolf in the lower 48 states and Mexico and list the Mexican wolf—a gray wolf subspecies—as endangered.165 At the time FWS published the 2013 proposed rule, the Northern Rocky Mountain DPS (including Wyoming) and the Western Great Lakes DPS were already delisted.166 In the proposed rule, FWS concluded that the gray wolf as listed at the time (i.e., gray wolves found in the lower 48 states that were not part of the Western Great Lakes or Northern Rocky Mountain DPSs) did not qualify as a “species” under the ESA, which is a requirement for listing under the Act.167 FWS noted that the listed entity was not an entire species or subspecies of gray wolf.168 It also concluded that the listed entity did not describe a valid “population” of gray wolves that could qualify as a DPS, and accordingly was not a “species.”169 FWS then evaluated whether the gray wolf as a taxonomical species or any subspecies or DPSs of the gray wolf merited listing as an endangered or threatened species.170 FWS determined first that 160 Endangered and T hreatened Wildlife and Plants; Removing the Gray Wolf (Canis lupus) from the List of Endangered and T hreatened Wildlife and Maintaining Protections for the Mexican Wolf (Canis lupus baileyi) by Listing It as Endangered, 78 Fed. Reg. 35,664 (June 13, 2013). 161 Endangered and T hreatened Wildlife and Plants; Endangered Status for the Mexican Wolf, 80 Fed. Reg. 2488 (Jan. 16, 2015). 162 Id. at 2511. 163 Endangered and T hreatened Wildlife and Plants; Removing the Gray Wolf ( Canis lupus) from the List of Endangered and T hreatened Wildlife, 84 Fed. Reg. 9648, 9686 (Mar. 15, 2019). For the status at the time of the proposed rule, see Table 1. 164 Endangered and T hreatened Wildlife and Plants; Removing the Gray Wolf (Canis lupus) from the List of Endangered and T hreatened Wildlife, 85 Fed. Reg. 69,778 (Nov. 3, 2020). 165 78 Fed. Reg. 35,664 (June 13, 2013). As a reminder, the ESA definition of species includes subspecies and DPSs. 16 U.S.C. § 1532(16). 166 T he rules delisting the gray wolf in Wyoming and the Western Great Lakes DPS were subsequently vacated by courts in 2014. Humane Soc’y of the U.S. v. Jewell, 76 F. Supp. 2d 69, 110-13 (D.D.C. 2014), aff’d by Humane Soc’y of the U.S. v. Zinke, 865 F.3d 585, 614-15 (D.C. Cir. 2017); Defenders of Wildlife v. Jewell, 68 F. Supp. 3d 193, 203 -10 (D.D.C. 2014). T he latter was later ordered to be reinstated by the D.C. Circuit in 2017 . Defenders of Wildlife v. Zinke, 849 F.3d 1077, 1082-84, 1093 (D.C. Cir. 2017). 167 78 Fed. Reg. at 35,673-78, 35,695. 168 Id. at 35,673. 169 Id. at 35,673-74. 170 Id. at 35,673-78, 35,695. Congressional Research Service 20 link to page 22 link to page 22 link to page 23 link to page 27 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges the gray wolf as a whole did not merit listing.171 FWS concluded that based on the best available data, there were three subspecies of gray wolf and, of the three, only the Mexican wolf was listable as endangered and the other two did not merit listing.172 Furthergray wolf merited listing as an endangered or threatened species.¹⁶⁰ In its analysis, FWS revisited the gray wolf's taxonomy, determining again that scientific evidence supported recognizing the eastern wolf as a full species (C. lycaon) and recognizing the following three gray wolf subspecies: C. lupus nubilus (found in the coastal areas of Alaska and Canada and the Pacific Northwest to the Great Lakes region), C. lupus occidentalis (found in the interior of Canada and the northern Rocky Mountains), and C. lupus baileyi (historically found in the American Southwest and Mexico).¹⁶¹ Within these species and subspecies, FWS did not identify any listable DPSs, finding that gray wolves of the gray wolf.173 In particular, FWS determined that gray wolves that had been sighted in the Pacific Northwest did not qualify as a DPS because it was not a population and, in any event, were not discrete from the Northern Rocky Mountain DPS population.¹⁶² FWS proposed to list the Mexican wolf as an endangered subspecies and delist the remaining listed gray wolf entities.¹⁶³ In 2015, FWS finalized its 2013 proposal to list the Mexican wolf separately but did not finalize the rest of the proposed rule.¹⁶⁴

The gray wolf is accordingly listed as endangered in the lower 48 states, except for the Northern Rocky Mountain DPS, which is delisted; the population in Minnesota, which is listed as threatened; and the Mexican wolf subspecies in New Mexico and Arizona, which is listed separately as endangered. 174 Having concluded that the listed entities did not qualify as a species, and finding only one listable species or DPS—the Mexican wolf, FWS proposed to delist the gray wolf where it was stil listed and list the Mexican wolf as an endangered species.175 In 2014, as discussed above, federal courts in the District of Columbia vacated the 2011 and 2012 rules delisting the Western Great Lakes DPS and delisting the gray wolf in Wyoming.176 Following these court decisions, in 2015 FWS finalized its 2013 proposal to list the Mexican wolf as endangered, but it did not finalize the rest of the proposed rule pertaining to delisting the gray wolf.177 In that rule, FWS adjusted the listing for the gray wolf in the lower 48 states and Mexico to exclude the Mexican wolf’s territory in Arizona and New Mexico from the territory over which the gray wolf is endangered.178 2020 Rule Delisting the Gray Wolf Listed Entities Except the Mexican Wolf In 2019, FWS published a proposed rule to delist two gray wolf listed entities: (1) the gray wolf in Minnesota and (2) the gray wolf in the lower 48 states and Mexico, except for the gray wolves: (a) in Minnesota, (b) in the Northern Rocky Mountain DPS, and (c) that are part of the gray wolf subspecies, the Mexican wolf.179 Though the listed entities had changed since the 2013 proposed rule, the effect would be the same—delisting al gray wolves except the Mexican wolf. The proposed rule did not address or affect the Mexican wolf that was listed separately in 2015.180 On 171 Id. at 35,673-74. 172 FWS recognized the following three gray wolf subspecies: C. lupus nubilus (found in the coastal areas of Alaska and Canada and the Pacific Northwest to the Great Lakes region), C. lupus occidentalis (found in the interior of Canada and the northern Rocky Mountains), and C. lupus baileyi (historically found in the American Southwest and Mexico). Id. at 35,717, 35,670-73. 173 Id. at 35,675-77. In its analysis, FWS also revisited the gray wolf’s taxonomy, determining that scientific evidence supported recognizing the eastern wolf as a full species, C. lycaon, separate from the gray wolf. Id. at 35,717, 35,670-73. 174 Id. at 35,675-77. 175 Id. at 35,718. 176 Humane Soc’y of the U.S. v. Jewell, 76 F. Supp. 2d 69, 110-13 (D.D.C. 2014), aff’d by Humane Soc’y of the U.S. v. Zinke, 865 F.3d 585, 614-15 (D.C. Cir. 2017); Defenders of Wildlife v. Jewell, 68 F. Supp. 3d 193, 203 -10 (D.D.C. 2014). T he latter was later ordered to be reinstated by the D.C. Circuit in 2017 . Defenders of Wildlife v. Zinke, 849 F.3d 1077, 1082-84, 1093 (D.C. Cir. 2017). For more information on these decisions, see “ Final Rule Designating and Delisting Western Great Lakes DPS in 2011 ” and “ Final Rule Delisting the Gray Wolf in Wyoming in 2012 .” 177 80 Fed. Reg. 2488 (Jan. 16, 2015). 178 Id. at 2511. 179 Endangered and T hreatened Wildlife and Plants; Removing the Gray Wolf (Canis lupus) from the List of Endangered and T hreatened Wildlife, 84 Fed. Reg. 9648, 9686 (Mar. 15, 2019). For the status at the time of the proposed rule, see Table 1. 180 84 Fed. Reg. at 9686; Endangered and T hreatened Wildlife and Plants; Endangered Status for the Mexican Wolf, 80 Fed. Reg. 2488 (Jan. 16, 2015). Congressional Research Service 21 link to page 27 link to page 12 link to page 12 link to page 46 link to page 46 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges November 3, 2020, FWS published a final rule, effective January 4, 2021, delisting the gray wolf listed entities except for the Mexican wolf, which remains listed as endangered.181 In the final rule, FWS concluded that the two listed entities are not “species” as defined by the Act, which is a requirement for listing.182 FWS observed that neither listed entity encompassed the entire taxonomic species or any subspecies of gray wolf, and accordingly could only be listable as DPSs.183 Neither listed entity qualified as a DPS, according to the FWS, because neither was discrete—the Minnesota wolves were not discrete from the remainder of the Western Great Lakes population, and the remaining entity listed as endangered was not discrete from the Minnesota wolves or the Northern Rocky Mountain DPS wolves.184 FWS also assessed the status of various gray wolf groups (i.e., whether they are threatened or endangered species), assessing the two listed entities, separately and combined, as wel as the two listed entities combined plus the Northern Rocky Mountain DPS wolves.185 FWS concluded that those various combinations of the gray wolf listed entities did not qualify as endangered species or threatened species under the Act.186 Pursuant to its determination that the listed entities did not qualify as species and its finding that the entities, separately or combined, did not qualify as endangered or threatened, FWS delisted the gray wolf entities.187 As mentioned, the final rule did not affect the listing for the Mexican wolf.188 The gray wolf is accordingly, as of January 4, 2021, delisted in the lower 48 states and Mexico, although the Mexican wolf remains listed as endangered. Several environmental groups have provided a notice of intent to sue to the Secretary of the Interior and Director of FWS, al eging that the final rule violates the ESA.189 Table 1 summarizes the history of listing, recovery, and delisting by DPS or region (described further in the "“History of Listing and Delisting the Gray Wolf" Wolf” section), andand Table A-1 in this report'’s Appendix provides a more detailed timeline. 181 85 Fed. Reg. 69,778 (Nov. 3, 2020). 182 Id. at 69,783-85. 183 Id. at 69,783. 184 Id. at 69,783-84. 185 Id. at 69,784-85. 186 Id. at 69,882, 69,885-86, 69,889, 69,893. 187 Id. at 69,778. FWS also returned to its position that the scientific community had not yet reached a consensus that the eastern wolf is a full species. Id. at 69,785-86. 188 Id. at 69,778. 189 Letter from Kristen L. Boyles & T imothy J. Preso, EarthJustice, to David Bernhardt, Sec’y, Dep’t of the Interior, & Aurelia Skipwith, Dir., U.S. Fish & Wildlife Serv. (Nov. 5, 2020), https://www.biologicaldiversity.org/campaigns/gray_wolves/pdfs/Gray-Wolf-60-Day-Notice.pdf. Congressional Research Service 22 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Table 1. Timeline: Gray Wolf Status by Population Western Great Lakes Northern Rocky Southwestern Remaining Date Population Mountain Population Population Lower 48 States 3/11/1967 Eastern timber wolf (C. lupus lycaon) listed 1/15/1973 Northern Rocky Mountain wolf (C. lupus irremotus) listed 4/28/1976 Mexican wolf (C. lupus baileyi) listed 6/14/1976 Texas wolf (C. lupus monstrabilis) listed 3/9/1978 Gray wolf listings consolidated to list as ful species in lower s Appendix provides a more detailed timeline.

Challenges When Listing and Delisting Species

FWS has encountered a host of legal challengeschal enges when listing or delisting the gray wolf.¹⁶⁸190 This section reviews by topic the substantive challengeschal enges FWS has encountered in rulemaking and litigation. Though specific to the gray wolf, the challengeschal enges FWS has faced provide insight into the issues the Services generallygeneral y encounter with listing and delisting species and how courts may react to the Services'’ approaches.

Identifying the Species

To identify a species as endangered or threatened, the Services must first identify what qualifies as a “species”as a "species" under the Act. When the ESA was enacted in 1973, it defined a species to include "“any subspecies of fish or wildlife or plants and any other group of fish or wildlife of the same species or smallersmal er taxa in common spatial arrangement that interbreed when mature."¹⁶⁹”191 In 1978, Congress amended the ESA to define species to include "“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."¹⁷⁰”192 Species and subspecies are biological concepts used in taxonomic classification.¹⁷¹193 As such, the Services consult experts in those fields to identify listable species and subspecies based on the best available scientific data.¹⁷²194 A DPS, however, is a statutory creation, not a biological concept.¹⁷³195 In 1996, the Services implemented the DPS Policy to outline how they would evaluate DPSs.¹⁷⁴196 Under the policy, a population must be discrete from other 190 See, e.g., Defenders of Wildlife v. Sec’y, U.S. Dep’t of the Interior, 354 F. Supp. 2d 1156 (D. Ore. 2005) ; Nat’l Wildlife Fed’n v. Norton, 386 F. Supp. 2d 553 (D. Vt. 2005); Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7 (D.D.C. 2008); Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160 (D. Mont. 2008) ; Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207 (D. Mont. 2010); Humane Soc’y of the U.S. v. Jewell, 76 F. Supp. 3d 69 (D.D.C. 2014), aff’d on other grounds Humane Soc’y of the U.S. v. Zinke, 865 F.3d 585 (D.C. Cir. 2017) . 191 Pub. L. No. 93-205, § 3, 87 Stat. 886 (1973). 192 Pub. L. No. 95-632, § 2, 92 Stat. 3752 (1978) (emphasis added). 193 See, e.g., SCIENCE AND THE ENDANGERED SPECIES ACT, NAT’L RESEARCH COUNCIL, NAT’L ACADEMY OF SCI. 56-57 (1995) (henceforth “NAS ESA Report”). 194 See, e.g., 78 Fed. Reg. 35,664, 35,669-73 (June 13, 2013). 195 DPS Policy, 61 Fed. Reg. at 4722. 196 Id. Congressional Research Service 25 link to page 29 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Under the policy, a population must be discrete from other populations, significant in accordance with principles of conservation biology, and endangered or threatened to be listed as a DPS.¹⁷⁵

Applying 197 Applying these criteria in practice has proven difficult. For the gray wolf in particular, FWS has encountered challenges encountered chal enges with the wolf'’s taxonomy and with regulating segments of the wolf population.

Taxonomy

population. Taxonomy Many of FWS'’s rulemaking preambles detail the difficulties involved in identifying listable entities and analyzing them in light of disagreements over the taxonomic classification of wolf species and subspecies. Under the ESA, FWS must be able to identify a listable entity—a full species, a subspecies, or a DPS—to analyze its status for listing.¹⁷⁶198 The entity identified for analysis determines the population(s), historical and current range, and threats that the Services consider. Though FWS'’s determinations about gray wolf taxonomy generallygeneral y have not been subject to direct legal challengeschal enges, they underpin how FWS conducts the remainder of its analyses to assess the species'’ status. Changing views and a lack of scientific consensus over the taxonomic classifications for the gray wolf have caused FWS to revise its analyses during or between rulemakings.¹⁷⁷

199 The Services must base decisions about what entity to evaluate on the "“best scientific and commercial data available."¹⁷⁸”200 But scientists do not always agree on their taxonomic conclusions.¹⁷⁹201 Taxonomists may classify species based on distinctive physical or behavioral traits, evolutionary pathways, interbreeding capabilities, or genetic composition.¹⁸⁰202 Taxonomists may disagree about whether and how to recognize subspecies within a species. Differences in methodology or datasets may also lead to disagreements about the taxonomic level to assign a particular entity. For example, various scientific studies have concluded that the eastern timber wolf is a full species (C. lycaon), a subspecies of gray wolf (C. lupus lycaon), a hybrid of different wolf species, a wolf-coyote hybrid, or a distinct gray wolf population not rising to the level of a subspecies.¹⁸¹203 Different methodological approaches may also affect how many entities within a species taxonomists recognize as distinct. For example, FWS has observed that scientific studies had recognized as many as 24 subspecies of wolves in North America but that other taxonomists had suggested there were actuallyactual y 5 or fewer subspecies.¹⁸²204 From these divergent scientific studies, the Services must determine what classification for an entity the "“best scientific and commercial data available" support.

The Services may also conclude that there is no scientific consensus on an entity'” support. 197 Id. at 4725. 198 16 U.S.C. §§ 1532(16) & 1533(a). T he ESA defines species to include subspecies and DPSs. Id. T he term “full species” does not appear in the statute but is used here to distinguish a taxonomic species from species as it is used in the ESA. 199 Compare 76 Fed. Reg. 26,086, 26,088-89 (May 5, 2011), with 76 Fed. Reg. 81,666, 81,668-69 (Dec. 28, 2011); com pare 78 Fed. Reg. 35,664, 35,669-70 (June 13, 2013), with 84 Fed. Reg. 9648, 9654-55 (Mar. 15, 2019). 200 16 U.S.C. § 1533(b)(1). 201 See, e.g., 78 Fed. Reg. at 35,670-73; 84 Fed. Reg. at 9654-55. 202 See, e.g., NAS ESA REPORT, supra note 193, at 51-54; 78 Fed. Reg. at 35,670-73. 203 See, e.g., 76 Fed. Reg. 26,086, 26,088-89 (May 5, 2011); 78 Fed. Reg. at 35,669-70. 204 Endangered and T hreatened Wildlife and Plants; Proposed Establishment of a Nonessential Experimental Population of Gray Wolf in Yellowstone National Park in Wyoming, Idaho, and Montana, 59 Fed. Reg. 42,108, 42,108 (Aug. 16, 1994). Congressional Research Service 26 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges The Services may also conclude that there is no scientific consensus on an entity’s taxonomic status that would be defensible based on the data.¹⁸³205 For example, twice FWS has proposed to recognize the eastern timber wolf as a full species only to conclude later that the scientific community had not reached a consensus on its classification.¹⁸⁴206 In each case, FWS reverted to the eastern timber wolf'’s original classification as a subspecies of gray wolf (C. lupus lycaon).¹⁸⁵207 It is unclear how FWS would have proceeded if it could not have reverted to a status quo. Any determination on taxonomic classification for listing purposes must be defensible based on the best scientific and commercial data available.¹⁸⁶

208 Classifications may also change over time as scientists reevaluate their conclusions based on additional data or improved methodologies.¹⁸⁷209 In its 2013 proposed rule, FWS determined that it would recognize only three gray wolf subspecies out of as many as 24 identified historicallyhistorical y—C. lupus nubilus (coastal wolf), C. lupus occidentalis (interior and mountain wolf), and C. lupus baileyi (Mexican wolf).¹⁸⁸210 As described above, FWS has continued to evaluate the taxonomic status of the eastern timber wolf as scientific research and opinion evolves.¹⁸⁹

211 Changing classifications and disagreements within the scientific community may result in a previously listed entity no longer qualifying as a "species"“species” under the ESA or in the Services being unable to identify any listable entity that qualifies as endangered or threatened. Such changes and disagreements can also affect other aspects of the Services'’ status analysis. For example, which areas FWS recognizes as comprising the gray wolf'’s current and historical range depends on whether the eastern timber wolf is a subspecies of gray wolf or a separate full species.¹⁹⁰212 Any areas solely occupied by the eastern timber wolf would be included in the gray wolf'’s range only if the eastern timber wolf is a subspecies. When FWS proposed to recognize the eastern timber wolf as a full species in 2011, it also proposed removing certain areas from the gray wolf listing that FWS considered listed in error because it determined that the wolves occupying those areas were eastern timber wolves rather than gray wolves.¹⁹¹213 In addition, the Services use a species' ’ current range to determine the species'’ status (i.e., whether it is endangered or threatened in "all “al or a significant portion of its range"¹⁹²”214) and use the historical range to assess threats against the species' species’ continued existence.¹⁹³215 Accordingly, changes to how a species is classified and defined can affect the Services'’ analysis of the species'’ status.

Defining DPSs

FWS' FWS’s efforts to designate and delist gray wolf DPSs have given rise to multiple legal challenges chal enges and vacated rules. To designate gray wolf DPSs, FWS has applied the DPS Policy. Under the 205 See, e.g., 76 Fed. Reg. at 26,088-89; 78 Fed. Reg. at 35,669-70. 206 Compare 76 Fed. Reg. at 26,088-89, with 76 Fed. Reg. 81,666, 81,668-69 (Dec. 28, 2011); compare 78 Fed. Reg. at 35,669-70, with 84 Fed. Reg. 9648, 9654-55 (Mar. 15, 2019). 207 76 Fed. Reg. at 81,668-69; 84 Fed. Reg. at 9654-55. 208 16 U.S.C. § 1533(b). 209 See, e.g., 78 Fed. Reg. at 35,670-73; 84 Fed. Reg. at 9654-55. 210 78 Fed. Reg. at 35,670-73. 211 Compare 76 Fed. Reg. at 26,088-89, with 76 Fed. Reg. 81,666, 81,668-69 (Dec. 28, 2011); compare 78 Fed. Reg. at 35,669-70, with 84 Fed. Reg. 9648, 9654-55 (Mar. 15, 2019). 212 76 Fed. Reg. at 26,088-89; 78 Fed. Reg. at 35,669-70. 213 76 Fed. Reg. at 26,142. 214 See 16 U.S.C. § 1532(6) & (20) (emphasis added). 215 See, e.g., 84 Fed. Reg. 9648, 9658 (Mar. 15, 2019). Congressional Research Service 27 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges and vacated rules. To designate gray wolf DPSs, FWS has applied the DPS Policy. Under the policy, the Services may designate a DPS if it is discrete from the remainder of the species and significant to the species.¹⁹⁴216 The Services determine a population is discrete if it is "“markedly separate"separate” from other populations based on "“physical, physiological, ecological, or behavioral factors"factors” or international boundaries.¹⁹⁵217 The Services determine that a population is significant—biologically and ecologicallybiological y and ecological y—based on whether the population persists in an unusual setting for the species, differs markedly from the rest of the species geneticallygenetical y, represents the only naturally natural y occurring population in the wild (i.e., excluding reintroduced populations), or would create a gap in the species range if the population were lost.¹⁹⁶218 The Services imposed the significance criteria to ensure they use the DPS designation authority "“sparingly,"” consistent with congressional guidance, to avoid potential abuse, such as listing numerous populations of otherwise abundant species.¹⁹⁷219 If the Services determine a population meets the discreteness and significance criteria, they evaluate the DPS'’s status to determine whether it is endangered or threatened in accordance with the ESA definitions and factors.¹⁹⁸

220 For the gray wolf, FWS has generallygeneral y evaluated discreteness by determining the distance between the areas occupied by different populations against average dispersal distances.¹⁹⁹221 The agency determined that the distances between the Western Great Lakes, Northern Rocky Mountain, and Mexican wolf populations were all al greater than three times the average dispersal distance for a lone wolf, leading FWS to determine that each population is discrete. FWS also has used the Canada-U.S. border to demarcate DPSs based on the different regulatory regimes in the two countries.²⁰⁰ countries.222 FWS determined the Western Great Lakes and Northern Rocky Mountain DPSs were significant because losing either population would leave a significant gap in the gray wolf's ’s range.²⁰¹223 In the 2003 rulemaking, FWS also determined that the Western Great Lakes, Western (later Northern Rocky Mountain), and Mexican wolf populations each displayed distinct morphological traits that could represent different subspecies, presumably meaning they were genetically distinct.²⁰² genetical y distinct.224 In the 2007 rule, FWS also concluded that the Western Great Lakes DPS persisted in a unique environment due to its presence in the Laurentian Mixed Forest Province where the boreal forest transitions to the broadleaf deciduous forest.²⁰³225 However, it did not rely on those factors in later rules.

FWS' FWS’s determinations that gray wolf populations meet the DPS Policy'’s discreteness and significance criteria generally general y have not been the subject of legal challengechal enge. Instead, parties have challenged FWS'chal enged FWS’s determination of DPSs'’ geographic boundaries.²⁰⁴226 The Oregon district court 216 DPS Policy, 61 Fed. Reg. 4722, 4725 (Feb. 7, 1996). 217 Id. 218 Id. 219 Id.; S. Rep. No. 96-151, at 6-7 (1979). 220 61 Fed. Reg. at 4725. 221 See, e.g., 72 Fed. Reg. 6052, 6059 (Feb. 8, 2007); 73 Fed. Reg. 10,514, 10,519-20 (Feb. 27, 2008). 222 See, e.g., 74 Fed. Reg. 15,123, 15,129 (Apr. 2, 2009). 223 See, e.g., 72 Fed. Reg. at 6059-60; 73 Fed. Reg. at 10,520; 74 Fed. Reg. at 15,129. 224 65 Fed. Reg. 43,450, 43,473 (July 13, 2000); 68 Fed. Reg. 15,804, 15,819 (Apr. 1, 2003). 225 Endangered and T hreatened Wildlife and Plants; Designating the Western Great Lakes Population of Gray Wolves as a Distinct Population Segment; Removing the Western Great Lakes Distinct Population Segment of the Gray Wolf from the List of Endangered and T hreatened Wildlife, 71 Fed. Reg. 15,266, 15,273-74 (Mar. 27, 2006); 72 Fed. Reg. at 6059-60. 226 Defenders of Wildlife v. Sec’y, U.S. Dep’t of the Interior, 354 F. Supp. 2d 1156, 1170 -71 (D. Ore. 2005). See also Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7, 14 (D.D.C. 2008) (declining to reach plaintiff’s argument regarding the DPS boundaries after finding another argument sufficient to vacate the rule). Congressional Research Service 28 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges The Oregon district court vacated FWS'’s rule designating the Western, Eastern, and Southwestern DPSs because it determined that FWS had inappropriately delineated the DPSs.²⁰⁵227 In that 2003 final rule, FWS had combined the proposed Western Great Lakes DPS and Northeastern DPS into the Eastern DPS after it did not obtain sufficient evidence of gray wolves inhabiting the Northeast to designate a DPS.²⁰⁶228 The agency also extended each DPS to include surrounding states such that the historical range of the gray wolf was carved up into DPSs.²⁰⁷229 The court determined that FWS had inverted the DPS Policy'’s purpose by combining populations with dramaticallydramatical y different statuses into one DPS based on geography.²⁰⁸230 The court held that FWS must delineate DPSs carefully to include only discrete, significant populations that qualify as DPSs and their occupied ranges.²⁰⁹

ranges.231 The Services'’ decisions to list a full species rather than a subspecies or DPS may also affect their ability ability to delist the species.²¹⁰232 Most of the challengeschal enges FWS has encountered with gray wolf DPSs have arisen when the agency has designated DPSs from listed full species for delisting purposes. Plaintiffs have argued that FWS can only designate a DPS to increase protections—either listing a DPS of a species or subspecies that is not listed or reclassifying a DPS to endangered if the species or subspecies is listed as threatened—and therefore can only delist a previously listed DPS.²¹¹233 FWS has contended that it has authority to delist a DPS from a listed species or subspecies based on (1) the statutory definition of species including DPSs and (2) its authority to review species'’ statuses and revise listings pursuant to new determinations or designations.²¹² 234 FWS has argued that its interpretation enables the flexibility Congress intended to provide the Services through the DPS category and is consistent with the Act'’s purposes by allowingal owing the the Services to direct resources to conserve those species or populations most in need of assistance.²¹³

235 Courts have concluded that the ESA is ambiguous as to whether FWS may designate and delist a DPS from a listed species or subspecies.²¹⁴236 District courts had initially initial y agreed with plaintiffs that FWS'FWS’s interpretation was impermissible because DPSs are a "“one-way ratchet"” and FWS may only delist a DPS it had previously listed.²¹⁵237 But the D.C. Circuit reversed the district court's ’s opinion in 2017, holding that it is reasonable to interpret the ESA as authorizing FWS to revise a full species or subspecies listing by designating and removing a DPS from the listed species.²¹⁶ 238 The D.C. Circuit also concluded, however, that FWS had improperly executed designating and delisting delisting the Western Great Lakes DPS in the 2011 rule because the agency must consider the effects of removing the DPS on the status of the listed remnant of the species in its analysis.²¹⁷ .239 Thus although this most recent decision determined that FWS has the legal authority to designate and delist decision determined that FWS has the legal authority to designate and delist 227 Defenders of Wildlife, 354 F. Supp. 2d at 1170-71. 228 68 Fed. Reg. at 15,809-10. 229 Id. at 15,818-19; Defenders of Wildlife, 354 F. Supp. 2d at 1172-73. 230 Defenders of Wildlife, 354 F. Supp. 2d at 1170-71. 231 Id. at 1171-73. 232 See, e.g., Defenders of Wildlife v. Zinke, 865 F.3d 585 (D.C. Cir. 2017). 233 See, e.g., Humane Soc’y of the U.S. v. Jewell, 76 F. Supp. 3d 69, 109-12 (D.D.C. 2014); Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7, 13 -14 (D.D.C. 2008). 234 See, e.g., 74 Fed. Reg. 15,070, 15,075-76 (Apr. 2, 2009); Humane Soc’y of the U.S. v. Zinke, 865 F.3d 585, 592-94 (D.C. Cir. 2017). 235 Humane Soc’y of the U.S., 865 F.3d at 593. 236 Humane Soc’y of the U.S., 579 F. Supp. 2d at 15-16. 237 See, e.g., Humane Soc’y of the U.S., 76 F. Supp. 3d at 109-25. 238 Humane Soc’y of the U.S., 865 F.3d at 600. 239 Id. Congressional Research Service 29 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges DPSs from listed species and subspecies, the agency has yet to do so in practice in a way that DPSs from listed species and subspecies, the agency has yet to do so in practice in a way that survives judicial review.

Experimental Populations

The ESA allowsal ows the Secretary to release specimens of listed species into the wild and designate the population as an "“experimental population"” if it is "“wholly separate geographically"geographical y” from from existing populations of the species.²¹⁸240 Experimental populations may be designated as essential or nonessential to the conservation of the species.²¹⁹241 An experimental population is protected as a threatened species even if the species is listed as endangered, allowingal owing the Services to limit which acts are prohibited with respect to the experimental population.²²⁰ Additionally, 242 Additional y, federal agencies are not required to enter into Section 7 consultations if their actions are likely to affect only nonessential experimental populations.²²¹243 These more limited protections afforded to experimental populations reduce the regulatory burden on the local community where the specimens are released, which may reduce public opposition to introducing (or reintroducing) the species to the wild in that area.²²²244 The Services must ensure that the released population is "“wholly separate geographically"geographical y” from existing populations to qualify as experimental and be subject to these reduced protections.²²³

245 FWS implemented two rules in 1994 establishing experimental populations of gray wolves in (1)  the greater YellowstoneYel owstone area and (2) central Idaho and southwestern Montana.²²⁴246 FWS evaluated whether these populations would be "“wholly separate geographically"geographical y” based on the areas occupied by existing gray wolf populations, not where any individual gray wolves—lone dispersers from the pack—might be found.²²⁵247 In the rules, FWS stated that it would treat any individual individual gray wolves found in the experimental population area as part of that population.²²⁶ 248 Farm bureaus, researchers, and conservation groups challengedchal enged this approach.²²⁷

A federal district court in Wyoming vacated the rules on three grounds, all centered on FWS's use of populations rather than individuals 249 240 16 U.S.C. § 1539(j)(1). 241 Id. 242 Id. 243 Id. 244 T he ESA was amended in 1982 to allow the Services to reintroduce listed species and designate them as experimental populations. Endangered Species Act Amendments, Pub. L. No. 97-304, 96 Stat. 1411 (1982) (codified at 16 U.S.C. § 1539(j)). T hough the Services had preexisting authority to reintroduce listed species, a court, reviewing the statute’s legislative history, concluded that Congress added this section to address the Services’ frustration with political opposition to such reintroduction efforts borne from “ industry’s fears experimental populations would halt development projects.” Wyo. Farm Bureau Fed’n v. Babbitt, 199 F.3d 1224, 1231-32 (10th Cir. 2000) (citing H.R. Rep. No. 97-567, at 8 (1982)). 245 16 U.S.C. § 1539(j)(1). 246 Endangered and T hreatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Gray Wolves in Yellowstone National Park in Wyoming, Idaho, and Montana, 59 Fed. Reg. 60,252, 60,253-54 (Nov. 22, 1994); Endangered and T hreatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Gray Wolves in Central Idaho and Southwestern Montana, 59 Fed. Reg. 60,266, 60,267 -69 (Nov. 22, 1994). 247 59 Fed. Reg. at 60,253-54; 59 Fed. Reg. at 60,267-69. 248 59 Fed. Reg. at 60,253-54; 59 Fed. Reg. at 60,267-69. 249 Wyo. Farm Bureau Fed’n v. Babbitt, 987 F. Supp. 1349, 1355 -57 (D. Wyo. 1997). Congressional Research Service 30 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges A federal district court in Wyoming vacated the rules on three grounds, al centered on FWS’s use of populations rather than individuals to evaluate geographic separation.250to evaluate geographic separation.²²⁸ First, the court held that FWS'’s interpretation was inconsistent with clear congressional intent by potentiallypotential y lessening protections for individual members of the species that ventured from protected populations into the experimental population'’s range.²²⁹251 Second, the court held that the rules conflicted with FWS'FWS’s own regulations, which require that any overlapping experimental and nonexperimental animals all animals al be treated as endangered under the Act.²³⁰252 Third, it held that treating all al gray wolves in the experimental area as part of the experimental population, including naturallynatural y occurring wolves who migrated there, effected a de facto delisting of those wolves contrary to the ESA.²³¹

253 On appeal, the U.S. Court of Appeals for the Tenth Circuit (Tenth Circuit) disagreed. It found that Congress left the phrase "“wholly separate geographicallygeographical y from nonexperimental populations"” to the Services to interpret.²³²254 Reviewing FWS'’s interpretation, the court observed that FWS's ’s regulations define the term "population"“population” as a group "“in common spatial arrangement."²³³”255 FWS had relied on this definition to conclude that individual dispersers would never be part of a "population" “population” and therefore need not be accounted for when assessing geographic separation of populations.²³⁴256 The court held that this interpretation was reasonable and consistent with the Act.²³⁵257 It pointed to the use of species, subspecies, and DPSs rather than individuals as evidence that the Act'’s purpose is to conserve groups of organisms, not individual specimens.²³⁶258 Consistent with that approach, the Tenth Circuit found that FWS reasonably determined the gray wolf's ’s current range based on where populations were located rather than where individuals might disperse.²³⁷259 Observing that wildlife—particularly wolves— moves, the court concluded that protecting specimens based on where they are rather than where they came from was a reasonable enforcement approach.²³⁸

260 The Tenth Circuit also held that the plaintiffs'’ contrary interpretation would require FWS to ensure that no individual specimens might cross between experimental and nonexperimental populations and would unnecessarily limit FWS'’s flexibility and discretion.²³⁹261 The court determined that such a restrictive interpretation would prevent FWS from making full use of the experimental population tool and could hinder the conservation of the species, undermining the purposes of the Act.²⁴⁰262 Accordingly, the Tenth Circuit reversed the district court'’s decision, allowingal owing the central Idaho and greater YellowstoneYel owstone area experimental populations to remain in place.²⁴¹263 Pursuant to the court'’s opinion, the Services may rely on areas occupied by populations 250 See generally id. 251 Id. at 1373-74. 252 Id. at 1375. 253 Id. at 1375-76. 254 Wyo. Farm Bureau Fed’n v. Babbitt, 199 F.3d 1224, 1234 (10th Cir. 2000). 255 Id. 256 Id. 257 Id. at 1234, 1237. 258 Id. at 1234. 259 Id. at 1234-46. 260 Id. at 1235-36. 261 Id. at 1236-37. 262 Id. at 1237. 263 Id. at 1241. Congressional Research Service 31 link to page 40 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges s opinion, the Services may rely on areas occupied by populations rather than individuals to determine whether an experimental population would be "wholly separate geographically"“wholly separate geographical y” as the Act required.

Qualifying as Endangered or Threatened

Determining whether a species qualifies as endangered or threatened for purposes of listing or delisting requires the Services to examine whether the species is in danger of extinction (1)  currently or in the foreseeable future, (2) in all al or a significant portion of its range, and (3) due to one or more of the five statutory factors categorizing types of threats. Though some commenters have disagreed with FWS'’s analyses of threats under the five statutory factors,²⁴² 264 those analyses have not generallygeneral y been a focal point in gray wolf litigation except for FWS's ’s assessment of state management plans'’ adequacy under the five statutory factors.²⁴³

"265 “All or a Significant Portion of Its Range"

” FWS has had difficulty in successfully interpreting "“significant portion of its range"”—particularly the "significant" the “significant” component—in connection with gray wolf rulemakings. Plaintiffs and commenters have repeatedly challenged FWS'chal enged FWS’s interpretation of "“significant portion of its range" ” in such rulemakings. Following an adverse court decision,²⁴⁴266 FWS currently treats "“significant portion of its range"” as an independent basis for listing a species, meaning FWS will wil list the species in all of its range if it finds that the species is endangered or threatened in either (1) all al or (2) a significant portion of its range.²⁴⁵267 FWS has successfully defended its interpretation of "range" “range” by interpreting the phrase to mean current rather than historical range.²⁴⁶268 But some courts have have recently rejected FWS'’s interpretation of which portions are "“significant."²⁴⁷”269 FWS has not yet issued a revised policy on the meaning of "“significant portion of its range"” or how it interprets "significant" “significant” in light of the new decisions.²⁴⁸

270 Interpreting the Terms "Significant" and "Range"

“Significant” and “Range” In its 2003 rule, plaintiffs challenged FWS'chal enged FWS’s interpretation of "significant"“significant” using the current "range"“range” of the species. FWS had used the gray wolf'’s current range (i.e., the areas occupied by the Western Great Lakes and Northern Rocky Mountain populations) as the "significant"“significant” areas when reclassifying the Eastern DPS and Western DPS as threatened.²⁴⁹271 An Oregon district court held that FWS failed to adequately justify why the areas occupied by these populations were the only "significant" ones.²⁵⁰ only “significant” ones.272 The court determined that FWS had instead relied on the gray wolf's current range, without considering the areas where the gray wolf "is no longer viable but once was."²⁵¹’s 264 76 Fed. Reg. 81,666, 81,682 (Dec. 28, 2011). 265 Challenges to FWS’s approval of state management plans, which may be analyzed in delisting rules as part of the factor addressing adequate regulatory mechanisms, are discussed in the “ Recovery and Delisting” section. 266 Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207, 1217-28 (D. Mont. 2010). 267 77 Fed. Reg. 55,530, 55,601 (Sept. 10, 2012). 268 See, e.g., Humane Soc’y of U.S. v. Zinke, 865 F.3d 85, 603-04 (D.C. Cir. 2017). 269 Ctr. for Biological Diversity v. Jewell, 248 F. Supp. 3d 946, 956 (D. Ariz. 2017); Desert Survivors v. U.S. Dep’t of the Interior, 321 F. Supp. 3d 1011, 1073 -74 (N.D. Cal. 2018) (order granting summary judgment to plaintiffs). 270 84 Fed. Reg. 9648, 9684 (Mar. 15, 2019) (interpreting “significant” for purposes of this rulemaking only). 271 Defenders of Wildlife v. Sec’y, U.S. Dep’t of Interior, 354 F. Supp. 2d 1156, 1165 -66 (D. Ore. 2005). 272 Id. at 1167-69. Congressional Research Service 32 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges current range, without considering the areas where the gray wolf “is no longer viable but once was.”273 Based in part on this conclusion, the court vacated the rule and remanded it to FWS.274 Based in part on this conclusion, the court vacated the rule and remanded it to FWS.²⁵²

On remand, FWS revisited its interpretation of the terms "range" and "significant"“range” and “significant” in its 2007 Western Great Lakes DPS rule:

• Interpreting "Range."  Interpreting “Range.” FWS explicitly interpreted "range"“range” to refer to the species' species’ current rather than historical range.²⁵³275 FWS based its interpretation on the fact that the ESA defines an endangered species or threatened species as one that "“is in danger of extinction"” at the time or in the foreseeable future.²⁵⁴276 FWS determined that while a species may be extinct in its historical range, it could only be in danger of extinction in all al or part of its current range.²⁵⁵277 The District of Columbia district court vacated this rule on other grounds,²⁵⁶278 but the D.C. Circuit subsequently upheld FWS'’s interpretation of range as reasonable.²⁵⁷279 FWS has since clarified that although it evaluates the current rather than historical range for purposes of determining the species'’ status, it considers the effect of losing the species'’ historical range when evaluating the statutory factors in listing decisions.280  Interpreting “Significant.”decisions.²⁵⁸
• Interpreting "Significant." FWS explained in the 2007 rule that it would determine what constituted a "significant"“significant” part of a species range on a case-by-case basis depending on the biological needs of the species.²⁵⁹281 To conduct this analysis, FWS would consider the ecosystems on which the species depends and the values identified in the Act.²⁶⁰282 Relevant factors might include the quality and quantity of habitat, the historical and current use of the habitat, specific uses for the habitat such as breeding or migration, and the role of that part of the range in maintaining genetic diversity.²⁶¹283 Though a federal district court in the District of Columbia subsequently vacated this rule, it did so on other grounds without reviewing FWS'’s interpretation of "“significant."²⁶²”284 The Solicitor'’s Office of the Department of the Interior issued an opinion soon after the final rule affirming FWS'FWS’s interpretation and providing a more extensive explanation of the position.²⁶³285 FWS relied on this interpretation and the Solicitor'’s opinion in subsequent gray wolf rulemakings.²⁶⁴

Beginning with its 2011 Western Great Lakes DPS rule, FWS adjusted its explanation of "significant portion of its range"286 273 Id. at 1167-69. 274 Id. at 1169, 1174. 275 72 Fed. Reg. 6052, 6069 (Feb. 8, 2007). 276 Id. at 6069-70 (emphasis added). 277 Id. 278 Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7 (D.D.C. 2008). 279 See, e.g., Humane Soc’y of U.S. v. Zinke, 865 F.3d 85, 603-04 (D.C. Cir. 2017). 280 See, e.g., 84 Fed. Reg. 9648, 9658 (Mar. 15, 2019). 281 72 Fed. Reg. at 6070-71. 282 Id. 283 Id. 284 Humane Soc’y of the U.S. v. Kempthorne, 579 F. Supp. 2d 7 (D.D.C. 2008). 285 The Meaning of “In Danger of Extinction Throughout All or a Significant Portion of Its Range,” OFFICE OF THE SOLICITOR, U.S. DEP ’T OF THE INTERIOR (Mar. 16, 2007). 286 73 Fed. Reg. 10,514, 10,533 (Feb. 27, 2008); 74 Fed. Reg. 15,123, 15,152 -53 (Apr. 2, 2009); 74 Fed. Reg. 15,070, 15,089-90 (Apr. 2, 2009). Congressional Research Service 33 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Beginning with its 2011 Western Great Lakes DPS rule, FWS adjusted its explanation of “significant portion of its range” to incorporate principles of conservation biology. The agency interpreted the phrase to mean that the area is (1) within the current range of the species and (2) “(2) "important to the conservation of the species because it contributes meaningfully to the representation, resiliency, or redundancy of the species."²⁶⁵”287 An area would "“contribute[] meaningfully" meaningfully” if loss of the area would negatively affect FWS'’s ability to conserve the species.²⁶⁶

288 In 2014, the Services issued a joint policy on their interpretation of "“significant portion of its range"range” under the ESA.²⁶⁷289 The policy was generallygeneral y consistent with FWS'’s and the Solicitor'’s past interpretations but contained a revised definition of "significant":

“significant”: A portion of the range of a species is "significant"“significant” if the species is not currently endangered or threatened throughout all of its range, but the portion'’s contribution to the viability of the species is so important that, without the members in that portion, the species would be in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range.²⁶⁸

290 District courts later invalidated this definition, concluding that a species could never be listed based on a "“significant portion of its range"” under this interpretation, and prohibited the Services from applying it.²⁶⁹291 These courts maintained that under this definition no species could be endangered or threatened in a significant portion of its range without being endangered or threatened in all al its range.²⁷⁰292 The courts reasoned that if a species were endangered or threatened in a "“significant portion"” of its range and would be endangered or threatened in all al of its range without that portion, then the species would be listable as endangered or threatened in all its range.²⁷¹293 In its 2019 proposed rule to delist the remaining gray wolf entities, FWS acknowledged that the policy had been invalidated and addressed the courts'’ opinions by reviewing the gray wolf' wolf’s range to identify any portion "“that could be significant under any reasonable definition of 'significant'‘significant’ that relates to the conservation of the gray wolf entity."²⁷²”294 The Services have not yet issued a revised policy interpreting the phrase "“significant portion of its range."

Using "Significant ” Using “Significant Portion of Its Range"” for Listing

Plaintiffs have also challenged FWS'chal enged FWS’s interpretation of "“significant portion of its range" to allow ” to al ow FWS to list a species only in those parts of its range where it is endangered or threatened. In its 2009 rule designating the Northern Rocky Mountain DPS and delisting it except in Wyoming, FWS implicitly interpreted the ESA as allowing al owing the agency to list a species only in that portion of its range where FWS determined the species was endangered or threatened.²⁷³295 This interpretation allowedal owed FWS to keep the DPS listed in Wyoming (based on inadequate regulatory mechanisms) 287 76 Fed. Reg. 81,666, 81,722 (Dec. 28, 2011). See also 77 Fed. Reg. 55,530, 55,601-02 (Sept. 10, 2012). 288 76 Fed. Reg. 81,666, 81,722 (Dec. 28, 2011). See also 77 Fed. Reg. 55,530, 55,601-02 (Sept. 10, 2012). 289 Final Policy on Interpretation of the Phrase “Significant Portion of Its Range” in the Endangered Species Act’s Definition of “Endangered Species” and “T hreatened Species,” 79 Fed. Reg. 37,578 (July 1, 2014). 290 Id. at 37,609. 291 E.g., Desert Survivors v. U.S. Dep’t of the Interior, 321 F. Supp. 3d 1011, 1073 -74 (N.D. Cal. 2018) (order granting summary judgment to plaintiffs); Ctr. for Biological Diversity v. Jewell, 248 F. Supp. 3d 946, 956 (D. Ariz. 2017). 292 Ctr. for Biological Diversity, 248 F. Supp. 3d at 956. 293 Id.; see also Desert Survivors, 321 F. Supp. 3d at 1073-74 (order granting summary judgment to plaintiffs). 294 84 Fed. Reg. 9648, 9684 (Mar. 15, 2019). 295 74 Fed. Reg. at 15,184. Congressional Research Service 34 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges FWS to keep the DPS listed in Wyoming (based on inadequate regulatory mechanisms) but delist it elsewhere.²⁷⁴296 A Montana district court vacated this rule on the grounds that FWS's ’s interpretation was inconsistent with the ESA and its legislative history.²⁷⁵297 The court determined that Congress added the phrase "“significant portion of its range"” to expand the circumstances under which the Services could list a species to address concerns that the ESA'’s predecessors limited the Services to listing species that were endangered worldwide.²⁷⁶298 The court accordingly concluded that the phrase was added to change "“when a species can be listed,"” not "“what must be listed and protected."²⁷⁷”299 The court also concluded that FWS'’s interpretation rendered superfluous DPSs and the vertebrate distinction for DPSs if the agency could limit its listing of a species to the part of its range that was endangered or threatened.²⁷⁸300 The court held that "“significant part of its range"” refers to whether, not where, a species is endangered or threatened.²⁷⁹301 In light of the court'court’s decision, FWS has subsequently interpreted this phrase to constitute an independent basis for listing a species throughout its range.²⁸⁰

302 Foreseeable Future

To determine whether a species is threatened, the Services must determine whether it is in danger of extinction in the "“foreseeable future."” Though FWS'’s interpretation of this phrase has not been the focus of legal challengeschal enges to rules relating to the gray wolf, FWS'’s interpretation of the term as it applies to the gray wolf has changed over time. OriginallyOriginal y, FWS used the term "“foreseeable future"future” in its analyses but did not interpret it in general or with respect to the gray wolf specifically.²⁸¹specifical y.303 In the 2007 Western Great Lakes DPS rule, however, FWS defined the term "“foreseeable future" specifically” specifical y for the gray wolf.²⁸²304 The agency determined that 30 years was an appropriate measure of the foreseeable future for the gray wolf because wolves have 3-year generations, so 30 years represented 10 generations of wolves.²⁸³305 FWS viewed 10 generations as a reasonable period to reliably predict the effects of threats on the species.²⁸⁴

306 FWS changed course again in the 2009 rules designating and delisting the Western Great Lakes DPS and Northern Rocky Mountain DPS.²⁸⁵307 Rather than defining the "“foreseeable future"” for the species as a whole based on its reproductive patterns, FWS announced that it would determine the foreseeable future for each threat it considered based on its ability to project and predict effects of the threats reliably.²⁸⁶308 For example, the agency used 30 years as the timeframe for available habitat and distribution models, but when considering the effect of genetic isolation on the species, it used a model that predicted those effects for the next 100 years.²⁸⁷309 Though FWS'’s gray wolf rules have not been overturned based on its interpretation of "“foreseeable future,"” its 296Id. 297 Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207, 1217-28 (D. Mont. 2010). 298 Id. at 1227-28. 299 Id. (emphasis in original). 300 Id. at 1224-25. 301 Id. at 1227. 302 See, e.g., 77 Fed. Reg. 55,530, 55,601 (Sept. 10, 2012). 303 See, e.g., 68 Fed. Reg. 15,804 (Apr. 1, 2003). 304 72 Fed. Reg. 6052, 6069 (Feb. 8, 2007). 305 Id. 306 Id. 307 74 Fed. Reg. 15,070, 15,088-89 (Apr. 2, 2009); 74 Fed. Reg. 15,123, 15,147, 15,156 -57 (Apr. 2, 2009). 308 74 Fed. Reg. at 15,088-89; 74 Fed. Reg. at 15,147, 15,156-57. 309 74 Fed. Reg. at 15,147, 15,156-57. Congressional Research Service 35 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges its approach is information as interpretations of this term have generated challengeschal enges for rules on other species.²⁸⁸

The Services' recent310 The Services’ 2019 revisions to their ESA regulations codify an interpretation of "“foreseeable future" future” much like the one FWS adopted in the 2009 rules.311 As revised, the Services interpret "“foreseeable future"” to "“extend[] only so far into the future as the Services can reasonably determine that both the future threats and the species responses to those threats are likely."²⁸⁹”312 The Services intend to evaluate "“foreseeable future"” on a case-by-case basis based on "“considerations such as the species'’ life-history characteristics, threat-projection timeframes, and environmental variability."²⁹⁰ variability.”313 Consistent with FWS'sthe approach adopted in the 2009in the more recent gray wolf rules, the Services state that they need not identify the foreseeable future as a specific time period.²⁹¹

314 Recovery and Delisting

The Services delist species using the same process they use to list species:²⁹²315 They evaluate whether the species meets the definition of "“endangered species"” or "“threatened species"” due to one or more of the five statutory factors based on the best available scientific and commercial data.²⁹³316 However, when delisting a species, the Services also generallygeneral y evaluate the species' ’ recovery pursuant to any identified objective recovery criteria in recovery plans and assesses the adequacy of state management plans following delisting.²⁹⁴317 FWS has stated that a species need not meet all al of the recovery criteria to be delisted.²⁹⁵318 But a Montana district court has required FWS to provide an adequate explanation if it chooses to reject recovery criteria or delist a species that has not met these criteria,²⁹⁶319 because FWS develops the recovery criteria pursuant to the statutory directive to establish "“objective, measurable criteria which, when met, would result in a determination ... that the species be removed from the list."²⁹⁷”320 State management plans fall fal under the purview of "“inadequate regulatory mechanisms"” in the five-factor analysis, but the Services give them particular attention in delisting rules because the regulatory mechanisms protecting a species necessarily change when it is delisted and no longer receives federal protection under the ESA. Accordingly, this section focuses specificallyspecifical y on two aspects of recovery and delisting species: (1) how FWS has addressed objective recovery criteria and (2) post-delisting state management plans.

Objective Recovery Criteria in Recovery Plans

Plaintiffs have challengedchal enged how FWS has used recovery plan criteria when assessing the gray wolf'wolf’s recovery in its delisting rules. The ESA directs the Services to develop and implement 310 See, e.g., In re Polar Bear Endangered Species Act Listing and Section 4(d) Rule Litigation, 709 F.3d 1, 15 -16 (D.C. Cir. 2013). 311 84 Fed. Reg. 45,020, 45,020-21 (Aug. 27, 2019) (codified at 50 C.F.R. § 424.11(d)). 312 Id. 313 Id. 314 Id. 315 16 U.S.C. § 1533(c). 316 Id. § 1533(a) & (b). 317 See, e.g., 72 Fed. Reg. 6052, 6052-56, 6083-95 (Feb. 8, 2007); 74 Fed. Reg. 15,123, 15,130-38, 15,166-75 (Apr. 2, 2009). 318 Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160, 1169 (D. Mont. 2008). 319 Defenders of Wildlife, 565 F. Supp. 2d at 1168. 320 16 U.S.C. § 1533(f)(1)(B)(ii) (emphasis added). Congressional Research Service 36 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges recovery plans for the conservation and survival of listed species if such a plan would promote conservation of the species.²⁹⁸321 In any such plan, the Services must include "“objective, measurable criteria"criteria” that, if met, would cause the Services to delist the species.²⁹⁹322 The Act, however, directs the Services to determine whether a species should be reclassified or removed from the list during a status review based on the Section 4(a) and (b) criteria—namely the endangered and threatened species definitions and the five statutory categories of threats as determined using the best available available commercial and scientific data—without mentioning recovery plan criteria.³⁰⁰323 Though these two provisions do not inherently conflict, they have generated questions about the role of objective criteria in recovery plans when delisting species.

Parties have challenged FWS'chal enged FWS’s decision to delist a species when it had not met all al of the objective recovery criteria. For example, plaintiffs challengedchal enged the 2008 rule to designate and delist the Northern Rocky Mountain DPS based in part on a study finding no evidence of genetic exchange between the greater YellowstoneYel owstone area population and the other two recovery areas.³⁰¹324 The 1994 EIS included as a recovery criterion that the northern Rocky Mountain recovery areas have " “[t]hirty or more breeding pairs comprising some 300+ wolves in a metapopulation (a population that exists as partiallypartial y isolated sets of subpopulations) with genetic exchange between subpopulations."³⁰²”325 The plaintiffs argued—and a Montana district court agreed—that this criterion required evidence of actual DNA exchange, not just the potential for genetic exchange or expectation of such exchange in the future.³⁰³326 The court held that although the ESA did not prohibit FWS from finding that a species had recovered without meeting recovery criteria, FWS still stil needed to justify adequately rejecting its own recovery criteria to avoid violating the APA.³⁰⁴

327 FWS addressed these criticisms in its 2009 Northern Rocky Mountain DPS rule in multiple ways. The agency challengedchal enged the factual conclusion that genetic exchange had not occurred by questioning the assumptions of the underlying scientific study and identifying new studies showing wolf dispersal and genetic exchange.³⁰⁵328 FWS further explained its interpretation of the recovery criterion, maintaining that the recovery criterion did not require confirmed genetic exchange and that genetic exchange need not result from natural migration and could be human-assisted.³⁰⁶ Finally assisted.329 Final y, the agency explained why the criterion was not needed to find recovery, reasoning that genetic exchange was not a concern for the populations due to the high level of preexisting genetic diversity.³⁰⁷330 In later rulemakings, FWS has stated that "“recovery may be achieved without all al recovery criteria being fully met."³⁰⁸”331 When there are questions about whether a species FWS seeks to delist has met objective recovery criteria, the agency may use one or more of the following approaches based on past practice: (1) explaining flaws in evidence showing the criteria have not been met; (2) finding additional evidence supporting its position; (3) explaining 321 16 U.S.C. §1533(f). 322 Id. §1533(f)(1)(B)(2). 323 Id. § 1533(c)(2). 324 Defenders of Wildlife, 565 F. Supp. 2d at 1168. 325 Id. 326 Id. at 1168-69. 327 Id. at 1170. 328 74 Fed. Reg. 15,123, 15,130-35 (Apr. 2, 2009). 329 Id. 330 Id. 331 84 Fed. Reg. 9648, 9657 (Mar. 15, 2019). Congressional Research Service 37 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges its understanding of the recovery criteria to explain why they have been met; or (4) explaining why it views the species as having recovered despite not explicitly meeting the objective criteria.

Finally Final y, parties have challengedchal enged the recovery criteria in comments on proposed rules as either excessive or inadequate to determine whether the species had recovered.³⁰⁹ FWS generally332 FWS general y has concluded that its recovery criteria are adequate,³¹⁰333 and, to date, courts generallygeneral y have not addressed FWS'’s technical expertise in selecting the criteria.

State Management Plans

State plans for managing a species post-delisting can enter into the Services'’ delisting determinations in two ways: (1) the Services examine any state management plans under "“Factor D: The Inadequacy of Existing Regulatory Mechanisms,"³¹¹”334 and (2) the Services may require in the recovery plan that they approve certain state management plans before delisting the species.³¹² 335 For the gray wolf, the Eastern Timber Wolf Recovery Plan required as part of its recovery criteria that Minnesota, Michigan, and Wisconsin have in place state management plans FWS had approved as providing adequate wolf protection and management.³¹³336 Similarly, the Northern Rocky Mountain Gray Wolf Recovery Plan required in its recovery criteria that Montana, Wyoming, and Idaho have FWS-approved state management plans.³¹⁴337 To meet this recovery plan requirement, (1) the state must create a management plan that FWS approves, (2) FWS must adequately explain why it approved the plan, and (3) the state must implement the plan.³¹⁵338 The state or FWS failing to complete any of these steps has delayed FWS delisting gray wolf populations and caused courts to vacate final delisting rules.³¹⁶

339 Formulating an Adequate Management Plan. First, the state must craft a management plan that FWS deems adequate to ensure the continued recovery of the species. In 2003, FWS designated but did not delist the Western DPS because the agency had rejected Wyoming'’s state management plan as inadequate. Wyoming challenged FWS'chal enged FWS’s decision to not approve its management plan, but a Wyoming district court dismissed the case for failing to tie the decision to any final agency action that could be reviewed.³¹⁷340 FWS took a different approach in 2009 when it delisted the Northern Rocky Mountain DPS without Wyoming because it determined that the Wyoming plan remained inadequate and could not be approved.³¹⁸341 But a Montana district court determined that FWS could not delist the DPS only in part, effectively holding that Wyoming must enact an approved state management plan for the entire DPS to be delisted.³¹⁹342 Congress superseded this 332 See, e.g., 72 Fed. Reg. 6052, 6066 (Feb. 8, 2007) (“T he 1992 Service Recovery Plan is outdated, and its recovery criteria cannot be used to justify delisting.”). 333 See, e.g., 72 Fed. Reg. at 6066. 334 See, e.g., 76 Fed. Reg. 81,666, 81,701-16 (Dec. 28, 2011); 74 Fed. Reg. 15,070, 15,103-17 (Apr. 2, 2009). 335 See 65 Fed. Reg. 43,450, 43,468, 43,475 (July 13, 2000). 336 Id. at 43,475. 337 Northern Rocky Mountain Wolf Recovery Plan, U.S. FISH & WILDLIFE SERV. at 32 (1987). 338 See, e.g. 65 Fed. Reg. at 43,475; Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160, 1163 (D. Mont. 2008); 74 Fed. Reg. 15,123, 15,123 (Apr. 2, 2009). 339 See, e.g. 65 Fed. Reg. at 43,475; Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160, 1163 (D. Mo nt. 2008); 74 Fed. Reg. 15,123, 15,123 (Apr. 2, 2009). 340 Wyoming v. U.S. Dep’t of the Interior, 360 F. Supp. 2d 1214 (D. Wyo. 2005). 341 74 Fed. Reg. at 15,123, 15,170-72. 342 Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207, 1217-28 (D. Mont. 2010). Congressional Research Service 38 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Congress superseded this decision by enacting legislation in 2011 that directed FWS to reinstate the rule delisting the DPS except for Wyoming.³²⁰

343 Explaining the Agency'sAgency’s Approval of the Management Plan. Second, FWS must adequately explain explain why it approved the state plan. In 2008, FWS delisted the Northern Rocky Mountain DPS after Wyoming revised its state management plan between the proposed and final rules.³²¹344 FWS proposed to delist the DPS only if Wyoming modified its plan to provide adequate protection for the species.³²²345 Wyoming modified its statutes and wolf management plan after the proposed rule was published.³²³346 In the final rule, FWS determined that the revised plan was adequate to ensure the gray wolf'’s continued recovery.³²⁴347 A Montana district court, however, held that FWS's ’s approval of Wyoming'’s plan was likely arbitrary and capricious and issued a preliminary injunction staying the delisting rule.³²⁵348 The court determined that the plan suffered from the same flaws that FWS had identified in the plan it previously rejected and that FWS had failed to adequately explain why the plan was now sufficient.³²⁶349 Several months after issuing the preliminary injunction, the court vacated and remanded the rule at FWS'’s request.³²⁷

350 Implementing the Management Plan. FinallyFinal y, the state must enact and otherwise implement, as applicable, the approved management plan to ensure that the protections the Services rely on to delist the species are actuallyactual y in place. For example, FWS stated in its 2000 proposed rule that it had intended to propose delisting the Western Great Lakes DPS as well wel as designating it but that the agency could not because the Minnesota legislature had failed to vote on the plan FWS had approved before FWS published its proposed rule.³²⁸351 FWS accordingly proposed to designate the DPS but not delist it because the recovery criteria were not met without an approved Minnesota management plan in place.³²⁹352 Once Minnesota enacted its plan, FWS moved forward with delisting the DPS (though courts ultimately vacated all al the rules that followed).³³⁰353 Similarly, FWS found Wyoming'’s management plan to be inadequate in the 2007 Northern Rocky Mountain DPS proposed rule because state laws and regulations prevented the Wyoming Game and Fish 343 Pub. L. No. 112-10, § 1713, 125 Stat. 150 (2011). 344 73 Fed. Reg. 10,514, 10,514, 10,549-50 (Feb. 27, 2008). 345 72 Fed. Reg. 6106, 6106, 6129-31 (Feb. 8, 2007). FWS decided that Wyoming’s existing plan was inadequate because, among other things, it designated the gray wolf as a predatory animal throughout the state outside the national parks that could be killed at any time by any means so long as there were at least 15 packs in the state or 7 packs outside the national parks. Id. at 6129. In the event these criteria were not met , the plan directed the Wyoming Game and Fish Commission to select areas in the state wh ere the gray wolf would be designated as trophy game subject to regulated take. Id. FWS determined that this plan did not ensure a sufficient number of breeding pairs would be maintained in the state. Id. at 6129-30. 346 72 Fed. Reg. 36,939, 36,940 (July 6, 2007). Wyoming revised its statutes and wolf management plan to designate the gray wolf as trophy game in those parts of the state FWS had identified as significant and committed to maintaining 7 breeding pairs outside the national parks, recognizing Wyoming does not have jurisdiction over the national parks and assuming that 8 breeding pairs would be maintained there. Id. 347 73 Fed. Reg. 10,514, 10,549 (Feb. 27, 2008). 348 Defenders of Wildlife v. Hall, 565 F. Supp. 2d 1160, 1172 -75 (D. Mont. 2008). 349 Defenders of Wildlife, 565 F. Supp. 2d at 1172-75. 350 73 Fed. Reg. 75,356, 75,357 (Dec. 11, 2008). 351 65 Fed. Reg. 43,450, 43,468, 43,475 (July 13, 2000). 352 Id. 353 See, e.g., 73 Fed. Reg. at 10,547-48; 74 Fed. Reg. 15,070, 15,103-05 (Apr. 2, 2009). Congressional Research Service 39 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges Commission from actual yproposed rule because state laws and regulations prevented the Wyoming Game and Fish Commission from actually implementing certain components of the plan.³³¹354 Once Wyoming modified its state laws and regulations, FWS approved the plan.³³²

355 As the litigation over the FWS'’s 2012 rule illustratesil ustrates, although states must enact management plans for the Services to move forward with delisting a species, the regulatory mechanisms need not al be legal ynot all be legally binding so long as states assure the Services that adequate protections will wil be provided in practice. The federal district court for the District of Columbia vacated FWS'’s 2012 rule delisting the gray wolf in Wyoming because FWS relied on nonbinding promises from Wyoming that it would manage the population above the minimum recovery level.³³³356 On appeal, the D.C. Circuit reversed the district court and restored the rule delisting the gray wolf in Wyoming, holding that "“regulatory mechanisms"” need not be binding with the force of law for FWS to determine they were adequate to protect the species.³³⁴

357 The Services'’ approval of state management plans and the adequacy of their explanations for approving the plans can accordingly play a central role in both finalizing delisting rules and surviving judicial review of those rules. For a particular species and state, the adequacy of the state'state’s regulatory mechanisms and management plan are determined on a case-by-case basis through negotiation between the state and the Services.

Conclusion

Conclusion The history of the gray wolf under the ESA illustrates the challengesil ustrates the chal enges FWS has faced in conserving the species as the Act intended. In implementing the ESA, the Services must contend with disagreements over how to interpret ambiguous terms, uncertain and ever-changing scientific data, and conflicting views on what it means to conserve species and the role of the states in that effort. These issues can complicate the Services'’ efforts to conserve endangered and threatened species and delist them, consistent with the Act'’s purposes.

Difficulties that delay delisting species may frustrate certain stakeholders, such as state wildlife agencies that want more flexibility in managing the species or private entities in the species' ’ habitat who must comply with the Act'’s prohibitions and Section 7 consultation requirements. Other stakeholders such as conservation groups or animal rights activists may raise concerns that species are inadequately regulated to ensure their long-term recovery or continued biodiversity due to uncertainties in the science and ambiguities in the statute. Either set of stakeholders may question whether the Act is effectively promoting the recovery of listed species.

In light of the scientific and administrative challengeschal enges FWS has encountered with regulating the gray wolf under the Act, Congress could consider amending the Act to address these issues and ensure the Act is implemented in accordance with congressional intent. Such legislation could amend the Act generally or specificallygeneral y or specifical y with respect to a particular action, such as the Act directing FWS to reinstate the rule designating and delisting the Northern Rocky Mountain DPS 354 72 Fed. Reg. 6106, 6106, 6129-31 (Feb. 8, 2007). 355 73 Fed. Reg. at 10,514, 10549-50. A court subsequently vacated this rule after determining that FWS was acted in an arbitrary and capricious manner in approving the Wyoming wolf management plan because it suffered from the same flaws as the 2003 plan FWS rejected. Defenders of Wildlife, 565 F. Supp. 2d at 1172-75. Wyoming revised its wolf management plan yet again and FWS ultimately delisted the gray wolf in Wyoming in 2012. 77 Fed. Reg. 55,530 (Sept. 10, 2012). 356 Defenders of Wildlife v. Jewell, 68 F. Supp. 3d 193, 196, 203-10 (D.D.C. 2014). 357 Defenders of Wildlife v. Zinke, 849 F.3d 1077, 1082-88 (D.C. Cir. 2017). Congressional Research Service 40 The Gray Wolf: A Case Study in Endangered Species Act Listing Challenges except for Wyoming.358except for Wyoming.³³⁵ Legislative proposals have been introduced in the 116th Congress that would pursue each of these approaches: amending the Act generally³³⁶ or specificallygenerally359 or specifical y directing FWS to issue new rules or reissue vacated ones regarding the gray wolf.³³⁷

Appendix. Timeline