1997-06-13_REPORT - M1981302 ‎(16)‎

• Permit No: M1981302
• IBM Index Class Name: Report
• Doc Date: 6/13/1997
• Doc Name: EXHIBIT A 12
• Media Type: D
• Archive: No

The effect of these land use practices on mouse distribution is poorly understood. Several
investigators have been puzzled at the lactic of jumping mice at sites with seemingly well structured
habitat, and the presence of mice at a few sites with less than optimal conditions. Lard use history
of an area may provide dues as to whether mice are at a site or it they can be restored. The
reviewers in the habitat group have compiled this fist of sox potential impacts that were though to play
a role in mouse distribution.
A)Trails
The construction and use of dirt and paved trails in riparian areas has become increasingly popular
In Colorado for recreational uses. These trails have a variety of users:walkers, runners, dogs and
bigdWs. Trails may be located directly adjacent to streams,dozens of meters away.or a
combination of distances. At this time, meadow jumping mice have been located along one
drainage complex that has heavy trail use(City of Boulder Open Space on South Boulder Creek and
associated ditches). Some capture locations are within 5 m of this dirt trail, but the greatest number
of capture locations are on the bank opposite the trail. It appears that dirt trails and their use does
not in itself exclude mica, but because there are so many variables inherent In the placement and
use of these trails,definitive conclusions cannot be drawn at this time.
8) Grazing
Jumping mice have been located on several sites where cattle are grazed. These sites include:
• City of Boulder Open Space, South Boulder Creek grazed under present regime for about 60
years,winter grazing(Nov-May),caw/pdf, moderate stocking;
• SLVram-grazing following haying;and
West Plum Creek-Jura-Sept,v-shaped fences limit access to water,cow/calf,moderate
sag-
As the ease with trade, it is dflfault to generalise on the occurrence of the mace and grazing
regimes, but meadow jumping mice have been found at sites with limited grazing. The timing and
intensity of grazing are probably key variables affecting mouse habitat The grazed sites listed above
ad have woody vegetation,and the maintenance of this cover is probably a key in maintairiirg mouse
habitat while the lard is grazed.
C)Mvting
Mkft operations, primarily for aggregate materials,often o= near riparian areas. These
opefMa usually destroy ewsting habitat and mouse populations are probably extirpated for
decades,if not forever. Wning operations can also indirectly affect habitat by altering downstream
hydrological flows of both surbce water and groundwater. Several of Ryon's historical sites had
mirwg operations nearby(within a few km),and these mining activities may have played a rope in the
cement absence of the mouse from these areas.
Ponds are often established as part of wetland reclamation following mining. There is some
evidence that jumping mice may use these ponds after axWbde habitat has developed. There are a
few ZW=captumes at Sawhill Ponds,which were established following mining around 19W
(Crraan. 1968). The wake Creek Ponds at Rocky Flats were established In the 1950s to capture
potential contaminant releases,and several of these area currently have high mouse densities.
The two pond sites mentioned were likely recolonized from populations that were nearby.
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