U.S. Fish & Wildlife Service
What is it?
When a species is proposed for listing
as endangered or threatened under
the Endangered Species Act (Act), we
must consider whether there are areas
of habitat we believe are essential to
the species’ conservation. Those areas
may be proposed for designation as
“critical habitat.” The determination
and designation of critical habitat is one
of the most controversial and confusing
aspects of the Act. Here are answers
to some of the most frequently asked
questions about critical habitat.
What is critical habitat?
Critical habitat is a term defined and
used in the Act. It is a specific geographic
area(s) that contains features essential
for the conservation of a threatened or
endangered species and that may require
special management and protection.
Critical habitat may include an area that
is not currently occupied by the species
but that will be needed for its recovery.
An area is designated as “critical habitat”
after we publish a proposed Federal
regulation in the Federal Register and
then we receive and consider public
comments on the proposal. The final
boundaries of the critical habitat area are
also published in the Federal Register.
What is the purpose of designating
Federal agencies are required to consult
with us on actions they carry out, fund,
or authorize to ensure that their actions
will not destroy or adversely modify
critical habitat. In this way, a critical
habitat designation protects areas that
are necessary for the conservation of the
A critical habitat designation has no
effect on situations that do not involve a
Federal agency—for example, a private
landowner undertaking a project that
involves no Federal funding or permit.
Do listed species in critical habitat areas
receive more protection?
An area designated as critical habitat
is not a refuge or sanctuary for the
species. Listed species and their habitat
are protected by the Act whether or
not they are in an area designated
as critical habitat. To understand the
additional protection that critical habitat
provides to an area, it is first necessary
to understand the protection afforded to
any endangered or threatened species,
even if critical habitat is not designated
n The Act forbids the import, export, or
interstate or foreign sale of endangered
and threatened animals and plants
without a special permit. It also makes
“take” illegal -- forbidding the killing,
harming, harassing, pursuing, or
removing the species from the wild.
n The Act requires that Federal agencies
conduct their activities in such a way as
to conserve species.
n The Act also requires Federal agencies
to consult with us to conserve listed
species on their lands and ensure that
any activity they fund, authorize, or carry
out will not jeopardize the survival of a
threatened or endangered species. This
is known as consultation.
In consultations for species with critical
habitat, Federal agencies are required
to ensure that their activities do not
adversely modify critical habitat to
the point that it will no longer aid in
the species’ recovery. In many cases,
this level of protection is similar to
that already provided to species by the
“jeopardy standard.” However, areas
that are currently unoccupied by the
species, but are needed for its recovery
Ash Meadows National Wildlife Refuge in Nevada provides critical habitat for eight
threatened or endangered species. Photo by Mike Bender, FWS.
are protected by the prohibition against
adverse modification of critical habitat.
Must Federal agencies consult with us
outside critical habitat areas?
Yes, even when there is no critical habitat
designation, Federal agencies must
consult with us to ensure any action they
carry out, fund, or authorize is not likely
to jeopardize the continued existence of a
What is the impact of a critical habitat
designation on economic development?
Most activities that require a Federal
agency to consult with us can proceed. If
modification of the project is necessary,
it is likely that those changes would have
been needed anyway, in order to avoid
jeopardy. However, in areas where the
species is not currently present, there
may be some project modifications that
would not have occurred without the
critical habitat designation.
How do we determine what areas to
designate as critical habitat?
Biologists consider physical and
biological features needed for life
processes and successful reproduction of
n space for individual and population
growth and for normal behavior;
n cover or shelter;
n food, water, air, light, minerals,
or other nutritional or physiological
n sites for breeding and rearing
n habitats that are protected from
disturbances or are representative of
the historic geographical and ecological
distributions of a species.
The areas shown on critical habitat maps
are often large. Are all the areas within
the mapped boundaries considered
No. Our rules normally exclude by text
developed areas such as buildings, roads,
airports, parking lots, piers, and other
such facilities. Additionally, projects
will only require consultation if they
affect areas that contain the primary
constituent elements required by the
species. Primary constituent elements
are those physical and biological features
of a landscape that a species needs to
survive and reproduce.
Why are large areas shown on critical
habitat maps if the entire area is not
actually considered critical habitat?
In such cases, precisely mapping
critical habitat boundaries is impractical
or impossible, because the required
descriptions for these precise boundaries
would be too unwieldy.
Does the Act require an economic
analysis as part of designating critical
Yes. We must take into account the
economic impact, as well as any other
benefits or impacts, of specifying any
particular area as critical habitat. We
may exclude any area from critical
habitat if we determine that the benefits
of excluding it outweigh the benefits of
specifying the area as part of critical
habitat, unless we determine that the
failure to designate the area as critical
habitat will result in the extinction of the
Does an economic analysis have any
effect on the decision to list a species as
threatened or endangered?
No, under the Act, a decision to list a
species is made solely on the basis of
scientific data and analysis.
Myths & Realities
If critical habitat is designated, does
that mean no further development can
No. A critical habitat designation
does not necessarily restrict further
development. It is a reminder to
Federal agencies that they must
make special efforts to protect the
important characteristics of these
Does a critical habitat designation
affect all activities that occur within
the designated area?
No. Only activities that involve a
Federal permit, license, or funding,
and are likely to destroy or adversely
modify the area of critical habitat will
be affected. If this is the case, we will
work with the Federal agency and,
where appropriate, private or other
landowners to amend their project to
allow it to proceed without adversely
affecting the critical habitat. Thus,
most Federal projects are likely to go
forward, but some will be modified to
minimize harm to critical habitat.
How many species have critical habitat
As of Agust 15, 2007, critical habitat
has been designated for 492 of the 1,351
U.S. species listed as threatened or
Why haven’t we designated critical
habitat for more species?
After a Congressional moratorium on
listing new species ended in 1996, we
faced a huge backlog of species needing
to be proposed for listing as threatened
or endangered. For this reason, we
have assigned a relatively low priority
to designating critical habitat because
we believe that a more effective use of
our limited staff and funding has been
to place imperiled species on the List of
Endangered and Threatened Species.
Additionally, the critical habitat
designation usually affords little extra
protection to most species, and in some
cases it can result in harm to the species.
This harm may be due to negative
public sentiment to the designation,
to inaccuracies in the initial area
designated, and to the fact that there
is often a misconception among other
Federal agencies that if an area is outside
of the designated critical habitat area,
then it is of no value to the species.
U.S. Fish & Wildlife Service
Endangered Species Program
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