1997-06-13_REPORT - M1981302 ‎(18)‎

• Permit No: M1981302
• IBM Index Class Name: Report
• Doc Date: 6/13/1997
• Doc Name: EXHIBIT A STATUS REPORT ON ZAPUS HUDSONIUS PREBLEI A CANDIDATE ENDANGERED SUBSPECIES
• Media Type: D
• Archive: No

construction of narrow, linear habitat has not compensated for the losses
of habitat converted to agricultural use. Residential and commercial
development throughout the known historical range of Z. h. preblei has
doubtlessly fragmented this subspecies' critical habitat. The management
of water resources for associated domestic and commercial water usage
has had a tendency to channelize and isolate water resources and
fragment, realign, and reduce riparian habitat.
2. Existing threats-The continued residential and commercial development,
or "urban sprawl" of the Colorado Piedmont area includes the cities of
Denver, Boulder, Fort Collins, and Greely, Colorado, and to a lesser
extent Laramie and Cheyenne, Wyoming. This conversion from natural
conditions and habitats to those of human use (i.e., structures, parking
lots, paved and unpaved roadways, walkways, trails, airports) continues
to fragment and extirpate potential critical habitat for this subspecies.
Agricultural uses and developments on critical meadow and riparian
habitats, such as construction and maintenance of irrigation canals,
permanent and temporary roadways, storage facilities, croplands, and the
grazing of livestock, will continue to remove or effectively destroy viable
habitat for this subspecies.
3. Potential threats- Future residential, commercial, municipal and
agricultural developments could threaten the remaining critical habitat of
Z. h. preblei.
B. Overutilization for commercial, sporting, scientific,or educational use-There
is no historical or current information that would indicate the this subspecies has
ever been exploited for commercial, sporting, scientific, or educational purposes.
In fact, the total number of study skins collected and maintained for this
subspecies is relatively low.
C. Disease, predation, or grazing- The number of parasites known to effect the
species Z. hudsonius is relatively low compared to other small mammal species.
The severity of parasitic inflictions are mild and have not been recorded to have
caused mortality in this species. Although the species is known to be preyed
upon by representatives of every major vertebrate group, and the species' primary
defense mechanism may seem potentially ineffective (remaining motionless and
camouflaged), there is no evidence that overudlization by predators has caused
a decline in the local subspecies. However, the subspecies may utilize habitat
associated with irrigation canals and associated riparian habitats. These narrow
habitat strips may be heavily frequented by avian and mammalian predators
because such habitats would be relatively more diverse and productive than the
surrounding drier upland habitat. The effect of grazing would be to reduce the
density and height of moist, lowland grasslands. Habitats supporting this critical
vegetation type would be likely candidates for conversion, both in the past and
in current times, into quality grazing and agricultural lands. There is some
evidence from live-trapping at Fort St. Vrain that the primary area of capture in
the 1970s has been converted to grazing land, and that the subspecies has been
adversely affected by grazing.
D. Inadequacy of existing regulatory mechanisms
1. Past threats- The establishment of agricultural lands and construction of
irrigation facilities was relatively unfettered during the period of
expansion toward the western United States. The development of
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