TESTIMONY OF STEVEN P. QUARLES
Subcommittee on Fish, Wildlife and Water
Environment and Public Works Committee
United States Senate
May 9, 2001
Issues Concerning the Listing of Distinct Population Segments of Vertebrates under the Endangered Species Act of 1973
My name is Steven P. Quarles. I am counsel to, and appearing on behalf of, the American Forest & Paper Association (AF&PA) and the QuadState County Government Coalition. AF&PA is the national trade association representing the forest products industry. It has more than 130 member companies that grow, harvest, and process wood and wood fiber and manufacture a wide variety of products including pulp, paper, paperboard and wood products. AF&PA has more than 60 association members that represent all facets of the forest products industry and represent more than 10,000 companies. AF&PA’s member companies, as a condition of membership, must also commit to conduct their business in accordance with the principles and objectives of the Sustainable Forestry Initiative (SFI)SM program. QuadState County Government Coalition is a coalition of six counties in the four States that share portions of Mojave and Colorado Deserts — Mojave County in Arizona; Imperial, Kern and San Bernardino Counties in California; Lincoln County in Nevada; and Washington County in Utah. The Coalition’s principal concern is the effect of the listing of the Mojave population of the desert tortoise on its member counties’ economic and revenue bases, their public works, and the businesses and properties of their constituents.
The topic to which the Subcommittee has devoted this hearing is timely and significant. Individual determinations or “listings” of species to be endangered species or threatened species (“listed species”) under the Endangered Species Act (“ESA”) have frequently been contentious because the stakes are high; imposed with the listings is the full panoply of the ESA’s controls over human behavior to benefit the listed species. However, for most of the ESA’s life span of nearly three decades, the general process (and the underlying science and law) of listing species as endangered species or threatened species has not garnered the same degree of controversy, or at least attention, as many of the other processes and decisions under that Act.
Controversy over and attention to the species’ listing process are now at hand, however — triggered by recent actions of both the Clinton and Bush Administrations. On November 17, 2000, FWS Director Jamie Clark announced that the agency lacks sufficient funds to conduct any species’ listings, including responding to any listing petitions, in fiscal year 2001 beyond those mandated by court order. This Clinton listings moratorium was followed by a legislative proposal in President Bush’s budget to waive for fiscal year 2002 the ESA’s statutory deadline for species listings (and designations of critical habitat) and to limit use of the available funding to implementing already issued court orders and those listings (and designations) the Secretary of the Interior in her discretion determines to be important. Both the Clinton moratorium and the Bush budget language, if enacted, should spawn litigation and enlist the judiciary in the intensifying species’ listing controversy.
My topic will focus on one issue: the overbroad definition of “species” eligible for listing under the ESA. In particular, I will emphasize the authority to list distinct population segments of vertebrates, efforts by Congress to determine the use of that authority, and how that authority has been abused by the ESA-implementing agencies (the U.S. Fish and Wildlife Service (“FWS”) and the National Marine Fisheries Service (“NMFS”) (collectively, the “Services)). The Services’ abuse of the distinct population segment concept has resulted in the expansion of their species’ listing authority well beyond the expectations of Congress and, in particular, this Committee, and the infiltration of the concept into other ESA decisionmaking processes for which it was not authorized or intended. I conclude with suggestions on ways Congress, in this time of funding scarcity, could limit the applicability of the distinct population segment concept for listing vertebrate species — a concept that provides the least amount of protection for genetic heritage, a principal purpose of the ESA.
The ESA only permits the Services to list an endangered species or threatened species if it is a “species” unit as defined by ESA § 3(16), and only if that “species” unit meets the definitions of “endangered species” or “threatened species” in ESA § 3(6) and 3(20) which requires a degree of risk over a “significant portion of [the] range” occupied by the species unit. 16 U.S.C. §§ 1532(6) and (20), 1533(a)(1) (FWS shall “determine whether any species is an endangered species or threatened species”), (a)(2), (a)(3), (b)(1), (b)(3)(A), and (b)(6)(A) (final “determination as to whether a species is an endangered species or a threatened species”).
The ESA defines the crucial term “species” in an unusual way. An ESA-listable “species” unit includes not only a true biological species (those individuals that can interbreed and produce viable offspring), but also a recognized “subspecies of fish or wildlife or plants,” and — in the case of a vertebrate species — “any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature” (“DPS”). 16 U.S.C. § 1532(16).
The ESA listing of any “species” unit has adverse consequences for private and public land uses within the range of that species. ESA § 9 and regulations prohibit the “take” of almost all listed wildlife species — the “take” prohibition bars any economic land use which would inadvertently harm even one member of that wildlife species. See 16 U.S.C. § 1538(a)(1); 50 C.F.R. §§ 17.3 and 222.102; Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687 (1995). Further, federally-assisted actions cannot be approved until an ESA § 7 consultation procedure has been completed, and must be disapproved if the action is likely to jeopardize the existence of the listed species unit. See 16 U.S.C. § 1536.
Each of the three branches of government has treated the authority to list distinct population segments of vertebrates in a strikingly different manner. If the analogy were to ships, two of the branches — Congress and the Executive — have passed in the night sailing in opposite directions; the third — the Judiciary — has never left port. Since the ESA’s enactment, Congress has made several efforts to reduce, met by countervailing efforts of the Services to expand, the scope of listings below the subspecies level. The federal courts have rarely been asked to pass judgment on these opposing efforts.
Congressional Efforts to Constrain Listings of Distinct Populations
Distinct population segments did not enjoy protection under the ESA’s predecessors. The Endangered Species Preservation Act of 1966 referred only to “species”; “subspecies” were added in the Endangered Species Conservation Act of 1969. The ESA’s first attempt to provide protection to species units below subspecies was quite liberal. As enacted in 1973, the ESA defined “species” to “include any subspecies of fish or wildlife or plants and any other group of fish or wildlife of the same species or smaller taxa in common spatial arrangement that interbreed when mature.”
Contrary to popular belief, many of the populations of charismatic megafauna that have been designated as endangered or threatened species were listed under this early, quite generous “common spatial arrangement” standard-less standard. These include species, such as the grizzly bear and bald eagle, that may have been rare in the lower 48 States but are common in Canada and Alaska. The listing documents made no attempt to demonstrate any degree of distinctness between the lower 48 species unit and the northern species unit; instead, they readily admitted that the two species units were not reproductively segregated and had no genetic or other biological differences. Moreover, the FWS made no effort to determine whether these “species” were suffering declines in Canada (or, for that matter, in the rest of the U.S., i.e., Alaska). Indeed, as one author noted, the FWS engaged in the ludicrous fiction of “defin[ing] the grizzlies’ entire range as the lower forty-eight states even though it was obviously well aware that grizzlies existed in Canada and Alaska.” (Daniel Rohlf, “There’s Something Fishy Going On Here: A Critique of the National Marine Fisheries Service’s Definition of Species Under the Endangered Species Act”, 24, Envtl. L. 617, 653 (1994).)
By 1978, Congress had had second thoughts about this loose “common spatial arrangement” authority for species’ listings. To restrict sub-subspecies listings, Congress amended the ESA by replacing the original definition of species with the present definition and its DPS language. Criticism continued, however; none more withering than that of the General Accounting Office (“GAO”). In 1979 testimony before this Committee and a report, the GAO raised concern over any loose definition of a “distinct population” in what has become the well-known squirrels-in-the-park analogy. The agency stated that the definition:
permitted FWS to list populations of species, regardless of their size, location, or total numbers. Thus, squirrels in a specific city park could be listed as endangered, even though an abundance of squirrels lived in other parks in the same city and elsewhere.... Such listings could increase the number of potential conflicts between endangered and threatened species and Federal, State, and private projects and programs.... However, the purpose of the Endangered Species Act is to conserve endangered and threatened species and their critical habitats, not preserve every individual animal and plant.
Endangered Species — A Controversial Issue Needing Resolution 52, 58 (GAO Rep. CED‑79‑65, 1979). Although the particular quote referred to the 1973 “species” definition, two lawyers and a scientist from NMFS pointed out in a law review article that subsequent GAO statements indicated the same concern was relevant to the revised 1978 “species” definition. (Karl Gleaves, Michael Kuruc, Patricia Montanio, “The Meaning of ‘Species’ Under the Endangered Species Act,” 13 Pub. Land L. Rev. 25, 31, n.30 (1992).)
This Committee took note of the GAO’s criticism (even if it viewed the problem as FWS’s interpretation of the statutory definition) and the GAO’s suggestion that the authority to list DPSs be deleted from the ESA. However, after FWS and others emphasized the importance of the listing flexibility afforded by the DPS portion of the “species” definition, this Committee decided to retain that definition in the 1979 ESA amendments and issue a stern admonition to the Services to use the DPS listing authority “sparingly”:
[T]he General Accounting Office recommended that the subcommittee consider an amendment to the definition of species currently contained in the act which would prevent the FWS from listing geographically limited populations of vertebrates as threatened or endangered. It is the GAO’s contention...that FWS has interpreted the term “species” to include any population of the animal, regardless of its size, location, or total numbers. According to the GAO, this could result in the listing of squirrels in a specific city park, even if there is an abundance of squirrels in other parks in the same city, or elsewhere in the country.... [T]he committee is aware of the great potential for abuse of this authority and expects FWS to use the ability to list populations sparingly and only when the biological evidence indicates that such action is warranted.
S. Rep. No. 151, 96th Cong., 1st Sess. (1979) at 6-7 (emphasis added).
The Services’ Unrestrained Use of the Distinct Population
Segment Listing Authority
Contrary to the “sparingly” stricture of this Committee, the Services have been more unsparing in their use of the DPS listing authority. They produced two documents purportedly defining and confining their DPS authority — NMFS’s “Policy on Applying the Definition of Species Under the Endangered Species Act to Pacific Salmon,” 56 Fed. Reg. 58612 (Nov. 20, 1991), which established the DPS concept of “evolutionarily significant unit” (“ESU”), and the Services’ joint “Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act”, 61 Fed. Reg. 4722 (Feb. 7, 1996). Both documents quoted, and paid lip service to, this Committee’s “sparingly” admonition. However, the Services’ actual performance in listing DPSs is clear evidence that their DPS policies do nothing to limit and, arguably, substantially expand the authority to list DPSs.
According to a draft manuscript prepared by the Pierce Atwood law firm for an upcoming edition of the American Bar Association’s Natural Resources and Environment magazine, since the existing “species” definition was added to the ESA in 1978, 59 DPSs have been listed by the Services, with the precise number dependant upon interpretation of decisions that, initially, did not always clearly identify the listings as DPSs. I suspect that there could be vigorous debate over whether 59 DPS listings in 22 years represents sparing use of the DPS listing authority. But once the trend — a rapid increase in DPS listings in the last several years — is examined, the nays should have it. The pace of DPS listings was relatively constant for the first 17 years (7 in 1978-1985; 6 in 1986-1990 (including NMFS’ first listing of a West Coast salmonid DPS); and 8 in 1991-1995). From 1996 through 2000, the Services have listed 38 DPSs, more than quadrupling the number of listings of the previous five years. This trend can be expected to continue; about 35 DPSs are currently involved in rulemaking processes.
By contrast, despite the existence of the Services’ two policies which ostensibly were to bring rigor to the DPS listing process, the Pierce Atwood authors could find only 13 instances over the past 22 years when either of the Services concluded that a particular population did not qualify as a DPS (excluding instances where DPS status was denied for de-listing purposes and where a DPS existed but was not listed for conservation reasons). The Services have concluded that species units have qualified as DPSs more than 80% of the time. These statistics suggest that the Services rarely determine that a species unit — identified by petitioners or by themselves — does not qualify as a DPS, notwithstanding Congress’ admonition to use the DPS listing authority “sparingly.”
Reasons for the Liberal Use of the Distinct Population Segment
How did this frequent use of the DPS listing authority happen in the face of the Congressional caution? I can think of at least three reasons.
1. No scientific agreement on the DPS concept. In general, common and consistent scientific understanding and usage of any units below the species level is absent. As one scientist put it: “The discussion of what makes a subunit within a species, be it a subspecies, race, ecotype, variety, or stock is such a durable source of dispute among systematic biologists that scientific consensus may never be achieved.” (Robert Taylor, “Biological Uncertainty in the Endangered Species Act,” 7 Natural Resources and the Environment 6 (1993).)
This scientific uncertainty becomes more severe at the DPS level. In the preamble to their 1996 joint DPS policy, the Services stated: “Available scientific information provides little specific enlightenment in interpreting the phrase ‘distinct population segment.’ This term is not commonly used in scientific discourse, although ‘population’ is an important term in a variety of contexts.” 61 Fed. Reg. 4722. With so little common scientific understanding of, or agreement on, the term DPS, it is too easy for the Services to use “the best scientific and commercial data available”, as required by ESA § 4(b) for listing decisions, to reach whatever conclusion they may wish. 16 U.S.C. § 1533(b)(1)(A). A committee of the National Research Council, in a 1995 report commissioned by members of Congress, while supporting a population listing concept of its own devising (“evolutionary unit”), admitted that even the one criterion everyone — Congress, the 1991 NMFS policy, and the (later) 1996 joint Services’ policy — could agree on for a listable population — “distinctness” — is as much a matter of judgment as science:
The most difficult questions generally arise at taxonomic levels below the subspecies level. Because evolutionary units at such levels are not discrete but exist along a continuum, it is a policy judgment as well as a scientific judgment to determine the significance of an evolutionary unit . . . . [S]cience alone does not lead to a conclusion that any objectively definable degree of distinction is more significant than another.
National Research Council, Science and the Endangered Species Act, 56 (1995) (emphasis added).
In other words, DPS is in the eye of the beholder.
2. The DPS policies of the Services are riddled with discretion. Certainly, an important purpose of the Services’ two DPS policies was to provide a measure of scientific rigor to the DPS decisionmaking in the listing process. The fact is they only pretend to do so. As one critic wrote about the more thoroughly analyzed and justified 1991 NMFS policy:
Much like the Wizard of Oz employed smoke and mirrors to lend him an air of might and wisdom, NMFS invokes science in an effort to portray its definitions of distinct populations eligible for listing as beyond question. When one looks behind the curtain, however, it becomes apparent that NMF’s ESU policy merely trades the discretion inherent in historic approaches to listing populations for a more technically complex but equally discretionary scheme. The tremendous discretion inherent in NMFS’ ESU policy stems from two related sources: scientific uncertainty and extremely imprecise definitions of the two ESU criteria: reproductive isolation and whether a population represents an important component in the “evolutionary legacy” of a species. (Rohlf at 644.)
When the Pierce Atwood authors reviewed the broader, less fully explained 1996 joint DPS policy, they found so much discretion that they concluded: “We are, in other words, back to the listing of squirrels in the city park.”
With this amount of discretion, the eyesight of the beholder can be quite poor, and yet suffice.
3. Neither Congress nor the courts have provided helpful guidance. The Service’s discretion in designating DPSs is unconstrained by any useful legislative or judicial direction. Congress has chosen not to define DPS, and the “legislative history provides some discussion of the concept but provides no specific guidance. It is probably safe to conclude not only that the meaning of ‘distinct population’ is ambiguous, but also that Congress has not directly addressed or resolved this precise question.” (Gleaves at 37-38.) The preamble to the 1991 NMFS policy concurs that “NMFS does not believe that the intent of Congress is clear as to the meaning of ‘distinct population.’ The ESA allows vertebrate populations that are ‘distinct’ to be considered ‘species,’ but does not explain how distinctness should be measured.” 56 Fed. Reg. 58613. Few courts have addressed, and none has provided a significant decision on, the meaning and application of the DPS concept.
Examples of Misuse or Abuse of The Distinct Population Segment Concept in Listing Decisions
The list of methods by which the Services expand their DPS listing authority by misuse or abuse of that authority could be lengthy. I will mention only three:
1. Designation of DPSs by political boundaries. In the early days, the Services listed species populations by international borders (e.g., grizzly), by State borders (e.g., bald eagles), and even by parishes (American alligator). Today, the Services typically eschew State and local boundaries for DPS listing purposes, but still adhere in their joint 1996 policy to the notion that national boundaries are perfectly permissible means of delineating DPSs. As I have noted, when the national border of the lower 48 States is used, the Services typically make no attempt to determine any reproductive isolation of, or other distinctness for, the U.S. portion of the multinational population, nor do they make any effort to learn the status of the portion of the population across the border (which is often abundant) or the other country’s management regime for that population portion. All too often, this is little more than species jingoism — a fervor to claim citizenship for as many species as we can. Moreover, since the Services ignore whether the species with the lower 48 DPSs are abundant in Alaska, they appear to side with the Seward’s Folly crowd that preferred the State to remain in foreign ownership or, at a minimum, they wish to restore a biological form of territorial status to our 49th State.
Unfortunately, Congress is complicit here. In 1973 and again in 1979, House and Senate reports expressed their intent to allow the Services to list domestic populations of species whose principal ranges are in another country, asserting (in the Senate report) that “the U.S. population of an animal should not necessarily be permitted to become extinct simply because the animal is more abundant elsewhere in the world.” H. R. Rep. No. 412, 93d Cong., 1st Sess. 10 (1973); S. Rep. No. 151, 96th Cong., 1st Sess. 7 (1979); quoted in Rohlf at 628-629.
Many scientists emphatically disagree. Unless the U.S. population is both reproductively isolated and biologically significant, both the National Research Council in its 1995 report and NMFS in its 1991 DPS policy found that there were no “sound scientific reasons” to delineate populations by political boundaries. NRC Report at 58; 56 Fed. Reg. 58613.
2. Designation of DPSs that are not reproductively isolated. One would have thought that an easy call for a criterion (but admittedly not always an easy matter of scientific proof) to determine a “distinct population segment” would be that the population must be reproductively isolated. After all, the plain ESA language connotes reproductive isolation. A population is “distinct” if it is separate from other members of the same biological species. A population develops “distinct” characteristics if it has a separate gene pool. The ESA phrase “population...which interbreeds when mature” suggests a population which interbreeds among itself but not with other populations. The NMFS lawyers and scientist in their law review article concur that this is the plain meaning of “distinct population”:
A common dictionary definition of “distinct” is “separate” or “apart from.” In addition, as a biological term, “population” includes the idea of reproductive isolation or separation. (Gleaves at 46.)
However, in their continual search for discretion, the Services have all but discarded the necessity to find reproductive isolation. For example, the 1991 NMFS policy states that the first criterion for delineating a DPS is that the Pacific salmon stock “must be substantially reproductively isolated from other conspecific population units” and declares that the “first criterion, reproductive isolation, does not have to be absolute, but it must be strong enough to permit evolutionarily important differences to accrue in different population units.” 56 Fed. Reg. 58618 (emphasis added). The Services’ joint 1996 policy weakens the reproductive isolation factor further. The policy does demand that the DPS be “markedly separated” but this can be as a result of “physical, physiological, ecological, or behavioral factors.” And, once again, “the standard adopted does not require absolute separation of a DPS from other members of its species. . . . The standard adopted is believed to allow entities recognized under the Act to be identified without requiring an unreasonably rigid test for distinctness.” 61 Fed. Reg. 4725, 4724 (emphasis added).
As one observer put it: “FWS has likewise waffled on the importance of genetic make-up in distinguishing between population segments. Predictably, the agency cited the presence or absence of genetic distinctiveness in instances in which it found reproductive isolation to be important, and downplayed genetics in cases where it had made listing decisions despite a lack of such isolation.” (Rohlf at 657.)
3. Designation of DPSs by disregarding the ESA’s definition of “species” and relying instead on the ESA’s definitions of “threatened species” and “endangered species.” In at least one listing of a population, the FWS abandoned any attempt to find any “distinct” quality to the population segment. It could not. It admitted the three-State population of Marbled Murrelets it wished to list was not reproductively isolated or particularly biologically distinct from the Canadian population. Therefore, it looked away from the statutory definition of species and DPSs, and, instead, discovered helpful language in the ESA’s definitions of “endangered species” and “threatened species.” 16 U.S.C. § 1532(6) and (20). FWS adopted an entirely different and certainly clever approach to defining DPSs by suggesting that the “significant portion of its range” language in both the “endangered species” and “threatened species” definitions could be made to serve as a means to delineate distinct populations without the need to demonstrate reproductive isolation or genetic or other differences. If this approach is followed in future listings, any population segment of any relative size could qualify for listing and the statutory requirement that the population be “distinct” will be sapped of all meaning.
The Services Have Inappropriately “Re-Listed” Smaller Species Units, Often As the Distinct Population Segments, In Decisionmaking Under Other Sections of the ESA
I would also like to bring to the Committee’s attention our view that the Services are inappropriately redefining species units after their listing into smaller species units in decisionmaking under sections of the ESA other than the ESA § 4 listing section.
The ESA is quite clear that ESA § 7 compliance, ESA § 4(f) recovery plans, and species de-listings decisions are to be made with reference to the same “species” unit that has been listed. See 16 U.S.C. §§ 1533(f), 1536(a)(2) and (b). Yet, in the case of the red-cockaded woodpecker (“RCW”) and in several other instances where the Services have listed a biological species, they are assessing ESA § 7 compliance not with reference to jeopardy to the listed biological species as a whole, but jeopardy to smaller subgroupings, such as an individual population of RCWs. This approach makes it far more likely that a localized action will be found to jeopardize a localized population and to violate ESA § 7. We believe that this approach is unlawful under the ESA, is contentious, and should be discontinued.
There has also been unwarranted “population creep” into ESA § 4(f) recovery planning and species’ de-listing actions. In several instances, where the FWS or NMFS has listed a larger “species” unit (e.g., the Mojave population of desert tortoises or grizzly bears in the lower 48 States), the agency has subdivided that “species” unit for de-listing purposes into smaller populations. These new multiple populations were, of course, designated without the formal rulemaking required for the listing of the original all-encompassing population (grizzly) or DPS (desert tortoise). The affected public was deprived of all the procedural protections of Administrative Procedure Act rulemaking which the ESA promised in its § 4 listing provisions. 16 U.S.C. § 1532(a)(1). Moreover, this division of the listed species, subspecies, or populations into smaller populations, often renamed with such titles as “recovery units,” likely extends the time for de-listing. For example, if five recovery units/mini-populations are designated in the recovery plan and four out of the five meet recovery plan standards for recovery, the FWS or NMFS likely could conclude that the entire listed population should be de-listed. But, under the Services’ practice, the agency would de-list only the four recovery units/mini-populations and leave ESA burdens in place for the remaining recovery unit/mini-population. And, that listing could last for a very long time because, in most instances where this practice has been followed, at least one of the recovery units/mini-populations has little chance of ever recovering.
The desert tortoise rendition of this practice is particularly interesting for another reason. After listing the Mojave population of the desert tortoise in 1990, the FWS divided that DPS into 6 smaller DPSs termed “evolutionarily significant units” in the 1994 recovery plan. FWS, Desert Tortoise (Mojave Population) Recovery Plan, June 1994, p. 19. NMFS formally adopted use of ESUs in its 1991 DPS policy for Pacific salmon. But, FWS has never adopted, or invited public comment on application of, such a policy for the terrestrial species within its jurisdiction. Instead, it applied another agency’s standard for certain anadromous fish to the tortoise. This isn’t “population creep,” its more of a “population scramble.”
Congress Should Consider Amending The ESA So That It Protects Only An Imperiled Biological Species, Or To Create A Presumption Against Listings Below The True Species Level, And To Limit The Use Of Species Elsewhere In The ESA To The Form Of Species Actually Listed.
If the local government and land use interests regulated by the ESA had been fully engaged when the ESA’s broad definition of “species” was adopted in 1973 and then narrowed somewhat in 1978, they likely would have preferred that the ESA simply define a “species” as a recognized biological species. That definition would eliminate the trivialization of the ESA that occurs when the Services list and create ESA compliance burdens for a subspecies or distinct population which is locally rare, even though the biological species as a whole is not imperiled. It also both would address the concerns raised by the Clinton listing moratorium and Bush budget’s legislative proposal by conserving the Services’ resources and would conform with the original legislative intent to: (1) protect the “genetic heritage” associated with a species’ unique gene pool, while (2) realizing that “it is beyond our capability to acquire all the habitat” needed by locally-rare populations “without at the same time dismantling our own civilization.” H.R. Rep. No. 93-412, at 4-5 (1973).
Indeed, in 1978, the House of Representatives voted to limit the ESA to a biological species. The full House adopted Representative Duncan’s amendment defining “species” consistent with its biological usage (a group of “physically similar organisms capable of interbreeding but generally incapable of producing fertile offspring through breeding with organisms outside this group”). 124 Cong. Rec. 38154-56 (Oct. 14, 1978). Rep. Duncan stated:
The legislation before us today is entitled, and I think this is important, “the Endangered Species Act.” It is not entitled, and I think this is important,..."An Endangered Subspecies Act,” or the “Endangered Variation‑of‑a‑Species Act.” The amendment preserves, again, the integrity of the legislation while sufficiently tightening up the definitions so that we do not afford protection of this legislation, to the detriment of man, to every individual creature on the face of the Earth that might differ in one degree or another from one of its brothers.
124 Cong. Rec. 38154.
However, given the history of ESA listings of subspecies and distinct population segments of vertebrate species, we suspect that removal entirely of the listing authority for either subspecies or DPSs would be a difficult undertaking. We also, as suggested by the focus of my testimony, find far more troublesome the sub-subspecies listing authority than the subspecies listing authority.
I would therefore suggest, as a possible alternative, that the ESA could be amended to: (1) require the Services to list a species or subspecies if it is biologically threatened or endangered; but (2) grant the Services the discretion to list or not list a DPS. Indeed, it may be appropriate for Congress to state a presumption, or default position, that DPSs should not be listed under the ESA, and to require the Services to provide judicially-reviewable reasoning if they decide to list such variations-of-a-species. This Committee suggested such a presumption when its report on the 1979 ESA amendments stated that:
the committee is aware of the great potential for abuse of this authority and expects FWS to use the ability to list populations sparingly and only when the biological evidence indicates that such action is warranted.
S. Rep. No. 151, 96th Cong., 1st Sess. (1979) at 6-7.
However, the ESA as written arguably requires the listing of any “species” unit (be it a biological species, a subspecies, or a distinct population segment of a vertebrate species) if that species unit is biologically endangered or threatened over a significant portion of its range. See 16 U.S.C. §§ 1532(6), (16) and (20), 1533(a) and (b)(1). Congress could remove these nagging questions on the Services’ discretion to not list a DPS by amending the ESA to clearly make listing at the population level discretionary and to provide in the form of a statutory command its previous Committee report admonition that such listing authority be exercised only “sparingly.”
Finally, I would urge the Committee to put an end to the inappropriate “population creep.” The Services should be directed to determine ESA § 7 compliance, prepare ESA § 4(f) recovery plans, and conduct ESA § 4 de-listings on the basis of the same “species” units that have been listed under ESA § 4.
 Though the House passed Rep. Duncan’s amendment, he was not named to the Conference Committee. The conferees reinserted the “species” definition that had been reported by the House Committee.