7939

• UCREFRP Catalog Number: 7939
• Author: Sidle, J. G.
• Title: Forum, Critical Habitat Designation
• USFW Year: 1987
• USFW - Doc Type: Is It Prudent?
• Copyright Material: YES

432 J. G. Sidle

This definition was as broad as the 1975 definition to
allow for the unique habitat needs of a variety of
species. A narrow defmition could have excluded
some species from having a CHD. The physiological,
behavioral, ecological, and evolutionary requirements
to be considered in a CHD were similar to those of
1975. CHD occurred after a species was listed, when-
ever and wherever deemed necessary and appro-
priate. In the first CHDs, no reasons are provided to
explain why the CHD was necessary or appropriate.
In 1978, the Endangered Species Act was amended
and CH was defined in the Act as:

(i) the specific areas within the geographical area occupied by a
species at the time it is listed in accordance with the Act, on which are
found those physical or biological features (I) essential to the conser-
vation of the species and (II) that may require special management
considerations or protection, and (ii) specific areas outside the ge0-
graphical area occupied by a species at the time it is listed, upon a
detennination that such areas are essential for the conservation of the
species.

This legal definition is more restrictive than the pre-
vious administrative definition. Some believed that
CHD would be misused, and viewed the proposed 4
million ha CHD (subsequently withdrawn) for the
grizzly bear (Ursus arctos) in Idaho, Montana, and Wy-
oming as an example of misuse of the CHD provision,
although the biology of this species necessarily de-
mands a large area. Congress wanted to limit CHDs to
areas needed for present survival. CHDs were not to
include areas for further expansion of species popula-
tions, unless such expansion was necessary for the sur-
vival of the species (Rosenberg 1980, Stromberg 1978).
The White River spined ace (Lepidomeda albivallis)
exemplifies current CHDs (CH definition was un-
changed by the 1982 amendments to the ESA). Three
springs and associated outflows and surrounding ri-
parian vegetation comprise the CHD (50 Federal Reg-
ister 37194). One spring is an area outside the present
geographical range occupied by the species, but essen-
tial for the species' conservation and within the historic
range of the species. The White River spinedace is
thought to have been extirpated from this spring
shortly before 1980. Efforts to reestablish the spine-
dace at this recent historical site are considered neces-
sary to increase the species' numbers and the genetic
viability of this species. The entire CHD satisfies all
known criteria for the species' ecological, behavioral,
and physiological requirements. Riparian areas are es-
sential for vegetative cover that contributes to the uni-
form water conditions preferred by the spinedace.
Constituent elements of the CHD include consistently
high quality cool (550-70oF) springs and outflows, and
surrounding land area that provides vegetation for

cover and habitat for insects and other invertebrates
on which the species feeds.

History of Listing and Critical
Habitat Designation

The listing of species and CHDs has been sporadic
since passage of the Endangered Species Preservation
Act of 1966 (Table 1). This is due to changing laws
(j ohnson 1979 and 1984), administrative processes,
and politics (Bean 1983, Ganong 1979). In the early
years, only certain types of species threatened with
worldwide extinction could be protected under US
law. The Endangered Species Conservation Act of
1969 further defined fish and wildlife to include am-
phibians, reptiles, mollusks, and crustaceans. The ESA
of 1973 allowed the listing of plants and other inverte-
brates. The 1973 Act also allowed the listing of popu-
lation segments of all species, except plants. The 1978
amendments limited the listing of population seg-
ments to vertebrates.
In the early years of listing, the current regulatory
process of publishing proposed and final listing rules
in the Federal Register was not followed. The ESA pre-
scribed a regulatory process, although listings could
still be made on the basis of lack of knowledge of a
species; that is, if information on a suspected endan-
gered or threatened species was scant, the species
could still be listed just to be on the safe side.
Later, status surveys were begun to correct some in-
accuracies associated with previous listings (US Gen-
eral Accounting Office 1979). Such surveys were to
determine the numbers and distribution of candidate
species for listing and to assess any threats to the
species. Surveys provided better understanding of
species habitats. However, listings and CHDs were
slowed by other regulatory requirements such as
public hearings and notices. The CHD process had
economic and other relevant impacts to consider. Such
consideration was to balance economic and biological
factors in CHDs. The US Department of the Interior
also imposed other economic analyses and reviews,
slowing the number of listings and CHDs (Bean 1983).
Fundamentally, the ESA now requires the examina-
tion of the economic effect of any CHD, and the gov-
ernment may exclude areas from a CHD in order to
lessen unwanted impacts so long as failure to designate
such areas will not result in extinction. Because eco-
nomic considerations are not permitted to delay a
species' listing, the economic examination has been
confined to the one year between the proposed and
final listing rules for a species. The ability to exclude
areas from a CHD, although it has never been exer-
cised, is intended to allow "tailoring" of CHDs. Of ten-