Order Code RS20263
Updated August 27, 2004
CRS Report for Congress
Received through the CRS Web
The Role of Designation of Critical Habitat
under the Endangered Species Act (ESA)
Pamela Baldwin
Legislative Attorney
American Law Division
Summary
The agencies that implement the Endangered Species Act (ESA) regard the
designation of critical habitat (CH) as providing only very limited benefits beyond those
achieved through the listing of species and the avoidance of jeopardy to them. Several
courts have now held that the relevant regulation and interpretation that result in this
conclusion are erroneous and do not carry out the intent of Congress. H.R. 2933 in the
108th Congress would change the definition of CH and move the time at which critical
habitat must be designated for a species from being (basically) concurrent with the
listing of the species to the earlier of either three years after listing or one year after
approval of a recovery plan for that species. H.R. 1662 would add additional
requirements relating to the use of science in CH designations. This report provides
background for considering the regulatory posture and current legislative proposals on
CH, and may be updated as circumstances warrant.
Introduction
The Secretary of the Interior, acting through the Fish and Wildlife Service (FWS),
and the Secretary of Commerce, acting through NOAA Fisheries, have duties under the
Endangered Species Act (ESA)1 to preserve and conserve species, including by
designating critical habitat (CH). Over several administrations, the agencies have asserted
that the current system for CH designation CH affords few additional benefits for species
beyond those provided by listing a species as endangered or threatened, and taking actions
to avoid jeopardizing a species’ continued existence.2 Several courts have now held that
the regulation and interpretation underlying the views of the FWS are erroneous and do
1 Act of December 28, 1973, P.L. 93-205, 87 Stat. 884, as amended, codified at 16 U.S.C. §§
1531 et seq. Responsibility for terrestrial and freshwater species rests with the Secretary of the
Interior, while responsibility for marine species and anadromous fish rests with the Secretary of
Commerce.
2 See 64 Fed. Reg. 31871 (June 14, 1999) when the FWS discussed this issue and called for
public comment on the current system.
Congressional Research Service ˜ The Library of Congress

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not carry out congressional intent. Proposals are currently before Congress that address
CH. This report3 is written as background for considering both the current legislative
proposals and the agencies’ position.
The preservation of ecosystems is one of the purposes of the ESA,4 and all federal
agencies must use their authorities to conserve species and the ecosystems upon which
they depend.5 The ESA protects habitat in many ways, including the definition of
prohibited “take” of listed species; the purchase of lands; cooperative programs with
states; consultation on federal actions or actions with a federal nexus; and issuance of
incidental take permits based, in part, on habitat protection. The act also requires the
designation of “critical habitat,” which is defined as areas essential for the “conservation”
of the species in question, which basically means that necessary for the recovery of the
species.6 Designation serves several important express purposes and also informs other
aspects of habitat protection under the act. Designation of CH may have fewer
consequences than many members of the public seem to believe, but may have more
consequences than the FWS asserts.
Habitat currently occupied by a listed species may be critical because it “may require
special management considerations or protection.”7 “Unoccupied” CH is the additional
suitable area necessary for the conservation of the species.8 Currently, CH must be
designated at the time a species is listed under the ESA, unless designation would not be
prudent (as when vandals or collectors could harm a limited habitat or species), or the CH
is not determinable.9
The appropriate Secretary must designate CH on the basis of the best scientific data
available and after taking into consideration the economic, national security, or other
relevant impacts, of designating a particular area as CH. The Secretary may exclude an
area from designation if the Secretary determines that the benefits of exclusion outweigh
the benefits of inclusion, unless the Secretary determines, based on the best scientific and
commercial data available, that the failure to designate the area will result in the
extinction of the species concerned.10 The designation of CH plays several direct and
indirect roles under the ESA.
3 This report does not address the conservation of plant species listed as threatened or
endangered.
4 16 U.S.C. § 1531(b).
5 16 U.S.C. § 1531(b) and (c).
6 Critical habitat is defined at 16 U.S. C. § 1532 (5); and see the definition of conserve at 16
U.S.C. § 1532(3), as meaning assisting species in reaching the point when they no longer need
the protections of the act.
7 16 U.S.C. § 1532(5). This language might have supported direct regulation of lands within
critical habitat, but has not been so interpreted.
8 16 U.S.C. § 1532(5)(A). The distinction between occupied and unoccupied habitat intended
by Congress is not clear.
9 16 U.S.C. § 1533(b)(6)(C).
10 16 U.S.C. § 1533(b). In practice, few areas have been excluded.

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Express Roles of Critical Habitat
1) Designation forces consideration of both species needs and the
impacts of protection. Designation of CH requires the Secretary to consider what
habitat is essential for conservation of the species and also the economic and other effects
of including certain habitat areas. Designation ensures that the habitat needs of a species
will be considered at the same time as the consequences of meeting those needs.
Alternatives in terms of areas to be included and management actions that might be taken
or recommended necessarily must be considered.
2) The designation process provides guidance for landowners.
Similarly, designation of CH results in publication of guidance to landowners through
consideration of the need for possible “special management and protection” of areas
within the CH. There appear to be public misperceptions that CH designation results in
binding federal restrictions on private lands. In fact, designation forces federal
consideration of all aspects of the habitat needs of a species and generates guidance to
landowners on avoiding penalties under the act, but has not been interpreted as
authorizing direct regulation. Guidance typically addresses activities not likely to be
viewed as prohibited “takes” and activities regarding which a landowner may wish to seek
additional guidance to avoid takes.
3) Designation requires “consultation” on federal actions. Designation
of CH primarily affects federal actions, but also private actions with a federal nexus.
Section 7 of the ESA (16 U.S.C. § 1536) requires each federal agency to insure that any
action authorized, funded, or carried out by the agency is not likely to jeopardize the
continued existence of a listed species or “result in the destruction or adverse
modification of ...” CH. (Emphasis added.) If an action is likely to jeopardize a species
or result in destruction or adverse modification of CH, the action agency must consult
with the FWS (or NOAA Fisheries). The consultation process applies to all actions by
federal agencies, and to all actions with a federal nexus through an approval, permit, or
funding, if there is reason to believe a listed species may be present in the project area and
is likely to be affected by project activities. Consultation entails study of the likely effects
of proposed actions, a statement by the Secretary on whether jeopardy or adverse
modification is found and suggestions for reasonable and prudent alternatives to the
harmful aspects of the proposed project in order to avoid jeopardy or destruction or
adverse modification of CH. All but a few projects have been able to proceed following
consultation.
4) Designation provides an opportunity for judicial review. In contrast
to other agency studies that may be done, designation of CH is a statutory duty and the
actions and non-actions of the FWS or NOAA Fisheries in this regard can be judicially
reviewed,11 including the adequacy of agency consideration of the habitat needs of the
species, the economic and other impacts of designation, and possible alternatives for CH
configuration.
11 16 U.S.C. § 1533(g)(1)(C).

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Indirect Effects of Critical Habitat Designation
The designation of CH may also play several indirect roles in the conservation of
species. While any habitat studies could serve many of these purposes too, designation
of CH is a required and reviewable federal duty that must include the elements discussed
above. It also is currently required to precede other actions that logically rest on the
information the designation process garners. Some of the indirect effects of designation
of critical habitat are:
1) The designation process provides information for §10 permits and
habitat conservation plans. Section 10(a) of the ESA (16 U.S.C. §1539(a))
authorizes the otherwise prohibited taking of listed species if the taking is an incidental
part of otherwise lawful activities and if the permit applicant submits a conservation plan
(known as a habitat conservation plan or “HCP”) that minimizes and mitigates the
impacts that likely will result from the taking. Adequate knowledge of the habitat needs
of the species in question is crucial to and underlies the process of HCP development and
approval and is critical to achieving adequate HCPs. Information on the habitat necessary
for the survival and recovery of the species in question, and on the relationship of
particular properties to these purposes, is crucial for all species planning. While habitat
information can be obtained by the responsible agency aside from the formal process for
designation of CH, the designation process is the required and reviewable means of
ensuring that adequate scientific information is in fact obtained and that the habitat needs
of the species have been considered simultaneously with a consideration of the economic,
national security, and other effects of habitat protection.
2) The designation process provides information for land acquisition
decisions. Similarly, the CH designation process provides information to inform
decisions on possible acquisitions of properties for habitat protection purposes under §
5 of the ESA (16 U.S.C. § 1534).
3) Critical habitat informs the meaning of “harm” in the definition of
“take”. At the heart of the ESA are its § 9 (16 U.S.C. § 1538) prohibitions against
“take” of endangered species. “Take” is defined not only as killing a listed species, but
also as harming species. Harm is defined in regulation as including “significant habitat
modification or degradation where it actually kills or injures wildlife by significantly
impairing essential behavioral patterns, including breeding, feeding or sheltering.”12
Therefore, destroying habitat in general may trigger penalties. As a practical matter, it
seems easier to demonstrate significant habitat modification or degradation if the habitat
in question had already been found to be critical to the conservation of the species in
question.
4) The designation process informs development of recovery plans.
Section 4(f) of the ESA (16 U.S.C. § 1533(f)) requires the preparation of a recovery plan
for each listed species. Recovery plans provide guidance on what actions, including
habitat maintenance and restoration, are necessary to recover a species. Here again, the
CH designation process can provide scientific knowledge of the habitat needs of a species
12 50 C.F.R. § 17.2 This regulation on harm was upheld against a facial challenge in Babbitt v.
Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687 (1995).

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and analysis of effects and impacts that could be crucial to an effective recovery plan.
Any agency habitat studies would be helpful in developing a recovery plan, but the
designation process, because it entails specific requirements and is reviewable, arguably
is likely to provide a more sound basis for recovery plans than less formal studies.
Agency Interpretation
The FWS has asserted that designation of CH provides little additional protection
beyond that provided by listing and the prohibition against jeopardy, yet consumes
significant amounts of funding, staff time, and other resources.13 As a result, FWS has
given designation such a low priority that the agency has completed CH designations for
only 36% of listed species as of August 9, 2004. However, the courts have found that the
agency does have a duty to designate CH,14 and that the regulation15 and interpretation on
which the FWS conclusions rest are erroneous and unlawful. Under § 7 of the ESA,
federal agencies must avoid jeopardizing a species or causing destruction or adverse
modification of CH. However, the FWS has conflated jeopardy and destruction or
adverse modification of CH by defining the latter phrase as meaning essentially actions
that diminish the value of critical habitat for the survival of the species, thereby
eliminating designation of habitat for recovery, and equating habitat modification with
jeopardy. A court noted that critical habitat is defined in the ESA as habitat which is
essential for the “conservation” of the species — i.e. recovery — and held that the
regulation is facially erroneous.16
The agency’s interpretation had resulted in eliminating most of the value of
designating unoccupied habitat since per se it is not needed for survival, and had
eliminated the value of CH designations for species listed as threatened, since such
species are not in immediate danger of extinction — both results that do not comport with
the language and legislative history of the ESA. The Ninth Circuit also has held the
regulation to be erroneous and contrary to Congressional will: “As the Fifth and Tenth
Circuits have already recognized, the regulatory definition reads the ‘recovery’ goal out
of the adverse modification inquiry; a proposed action ‘adversely modifies’ critical habitat
if, and only if, the value of the critical habitat for survival is appreciably diminished.”17
13 See 64 Fed. Reg. 31872.
14 See, e.g., Conservation Council for Hawaii v. Babbitt, 24 F. Supp. 2d 1074, 1078 (D. Hi. 1998),
in which the court set deadlines for the FWS to designate critical habitat for a number of species,
even if funds were short (a situation plaintiffs alleged FWS was partially responsible for), and
that the agency’s remedy for its listing duties and funds was Congress.
15 50 C.F.R. § 402.02. The regulations apply to actions of both FWS and NOAA Fisheries, but
most of the court cases have involved the FWS.
16 Sierra Club v. U.S. Fish and Wildlife Service, 245 F. 3d 434 (5th Cir. 2001); cited with
approval in New Mexico Cattle Growers Ass’n v. FWS, 248 F. 3d 1277, 1283 (10th Cir. 2001).
17 Gifford Pinchot Task Force v. U.S. Fish and Wildlife Service, 2004 U.S. App. LEXIS 16215
at *22.

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Legislation in the 108th Congress
Concerns over national security after September 11, 2001 resulted in amendments
to the ESA regarding designation of CH. One change requires the consideration of
impacts on national security during the designation process. Another precludes
designating CH on any lands or other geographical areas owned or controlled by the
Department of Defense or designated for its use that are subject to an Integrated Natural
Resources Management Plan prepared under 16 U.S.C. § 670a, if the Secretary
determines in writing that such plan provides a benefit to the species18 — arguably a low
threshold to meet.
Several pending bills could affect CH. H.R. 2933 would change the definition of CH
to be habitat determined by field studies to be occupied and used for essential behaviors,
plus additional habitat necessary for the survival, as opposed to recovery, of the species,
as current law requires. The bill would move the time for designation of CH to the earlier
of either three years after listing, or one year after approval of a recovery plan, and would
preclude CH designation for any areas covered under a §10 incidental take permit (and
possibly even under a submitted habitat conservation plan), or under a state or federal land
conservation or species management program that offers substantially equivalent
protection. It would also strengthen consideration of economic costs and benefits to
governments and landowners and require the Secretary to designate CH to the maximum
extent “practicable,” in addition to the current standard of “prudent, and determinable.”
This change could result in fewer CH designations.
The ESA requires the use of the best scientific and commercial data available. H.R.
1662 would add several provisions relating to this requirement. It would require greater
weight to be given to empirical data that have been subject to peer review and would
require the Secretary to “accept” data from landowners. It is not clear whether this last
requirement means to physically receive such data, or to accept the data as valid. Three
person peer-review panels would be created for several agency actions, including the
designation or adverse modification of CH. It is not clear how these panels would
function in practice.19
18 P.L. 108-136, Div. A, Title III, § 318, 117 Stat. 1433. (Emphasis added.)
19 For more information, see CRS Report RS21500, The Endangered Species Act (ESA), ‘Sound
Science,’ and the Courts, by Pamela Baldwin, and CRS Report RL31546, The Endangered
Species Act and Science: The Case of Pacific Salmon, by Eugene Buck, et al.

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