WSP03664

• File Number: 8065
• Description: Section D General Statewide Issues - Endangered Species Act - Fisheries
• State: CO
• Basin: Statewide
• Date: 8/1/1993
• Author: American Bar Associa
• Title: Natural Resources and Environment - Number 8-Volume 1 - Summer 1993 - Endangered Species Protection
• Water Supply Pro - Doc Type: Publication

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Figure 2, Political and Ecological Boarders
in the United States and Canada

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.

Political Map

tional approach. BIOGEOGRAPHY 57 (C.V. Mosby
& Co. 1983). E. Mayr declared that "the range
of a species is delimited by a line beyond which
the selective factors of the environment prevem
successful reproduction." POPULATIONS, SPECIES,
AND EVOUITIoN 30 I (Harvard Univ. Press 1970).
This would generate a boundary somewhat
higher than that of Brown and Gibson. M.D.F.
Udvardy had earlier restricted the boundary even
more by assening that "the limit of a well.doc-
umented area should connect those extreme
breeding stations which are not fanher from one
another than the distance that can regularly be
covered by normally dispersing individuals of
the species." DYNAMIC ZOOGEOGRAPHY 164 (Van
Nostrand Reinhold 1969). R. H. MacAnhur noted
that "we could also . . . define the nonhero
edge of the range as the point where the pop.
ulation density falls to, say, one.twentieth of its
density in the middle of the range or one-twen-
tieth of its maximum density." GEOGRAPHiCAl
ECOLOGY 146 (Harper & Row 1972). This def-
inition might draw a line well up Figure 1.
At present we (end to use the systematic
biology or, at most, the Brown and Gibson def.
inition of range. The practical problem with the
use of these more liberal definitions is that they
include patchy fringe populations within the
range boundaries. This means that the inference
of human. caused breaks in a species' distribu.
tion near its range limits can be drawn only from
a comparison of the existing situation (Q the
natural pattern of patchiness, and data to de.
scribe that natural pattern seldom exist. The only
way to avoid this problem is to define the range

.

Biological Map

boundary more conservatively, and that neces-
sarily means that some fringe locations capable
of suppotting a species will be excluded.
Resolution of this problem wi 11 not be triv-
ial. It must begin with political insistence that
the scientific community address the question
of defining a species' range. It should conclude
at leas! with a thoughtful set of rules by FWS.

Political Boundaries versus

Species Boundaries

The gray wolf is one of the more contro-
versial entries on the list of threatened and en-
dangered species. Where it exists in Minnesota
and Wisconsin it has caused endless bickering.
Where it is penetrating the northern Rockies, it
has precipitated a major political battle. All of
this has occurred despite the fact that if you ask
nearly any group of professional wildlife biol-
ogists if the wolf is threatened with extinction,
their answer will be a resounding no! Wolves
currently number fifty thousand to sixty thou-
sand animals and occupy the vast majority of
their original range in Canada and Alaska. The
clear fact, acknowledged by all sides in this dis-
pute, is that the fight over the wolf is a fight
over symbols or land use; it is not a fight to
preserve a species at risk of extinction.
To understand why we have embarked on
such a policy, compare a political map of the
United States and Canada with an ecological map
of the major biomes (Figure 2). The processes
Continued on page 58

NR&E/SUMMER 1993

The fight over the
gray wolf is a fight
over symbols or
land use, not a fight
to preserve a species
at risk of
extinction.

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