NEPA--Environmental Assessment

unlikely that any of these species will be adversely affected by sheep because Machaeranthera
coloradoensis and Gilia sedifolia occur in remote places sites where sheep are unlikely to go, and
because sheep tend to not spend much time in wetlands where Cryptogramma stelleri, Carex
viridula, Eriophorum chamissonis, Eriophorum gracile, Eriophorum altaicum var. neogaeum and
Parnassia kotzebuei occur.
Alternative 3
Under this alternative, livestock grazing intensity (defined in Alternative 1) would be low. Sheep
would graze and sometimes overgraze forage plants in the project area (particularly forbs), as
described in Alternative 2, but the reduced livestock grazing intensity (compared to Alternative 2)
would reduce the potential for overgrazing and trampling which often occurs at bedgrounds, and
allow forage plants to increase their vigor and root reserves, which would increase their chances for
survival by increasing their ability to reproduce, compete, and withstand drought, disease, fire, and
grazing (Heitschmidt and Stuth 1993). Increasing the abundance and vigor of plant species would
increase the amount of ground cover (vegetation and litter) and decrease the amount of bare soil,
which would likely increase infiltration, and decrease runoff and erosion.
This alternative would result in improved ecological conditions compared to current conditions
(Alternative 2) since the livestock grazing intensity, timing, and the rotation grazing system would
change, resulting in a decrease in the frequency and duration of sheep use. Since sheep spend most
of their time in the turf type, the potential for adverse effects from sheep grazing would be greater
there compared to the other alpine vegetation types. But adverse effects to plants and soils from
sheep grazing and trampling in all the vegetation types in the project area (including the turf type,
riparian areas, and wetlands) would be minor. Adverse effects to plants and soils from sheep trailing
and sheep bedgrounds would not occur or would be minor. Also under this alternative, the desired
conditions for BLM lands and Forest Service lands would continue to be met.
The impacts to vegetation and soils from closing allotments would result in ecological conditions
that are similar to current conditions since livestock have already been absent from these allotments
for many years.
The impacts of reducing the season of use, reducing sheep numbers, reducing the number of days of
sheep utilization, resting from sheep grazing, and seeding herbs into the project area (all of which
could be implemented in the future under adaptive management) would result in improved
ecological conditions for the vegetation and soils of the project area, since all these management
actions would reduce grazing intensity and the associated adverse effects to plants and soils, increase
the abundance and distribution of desirable native herbs, and decrease bare soil.
Noxious weeds would continue to be present in the analysis area under this alternative. Permitted
livestock would continue to be a factor in the spread of noxious weed seeds, along with the other
uses in the analysis area. As with Alternatives 1 and 2, the spread of noxious weed populations
would be more dependent upon treatment intensity than upon livestock grazing. This alternative
provides the adaptive option for introduction of biological control to the worst locations of
infestation. While biological control would help to decrease the vigor and spread of noxious weeds,
it would not eliminate them.
Impacts from livestock grazing to threatened, endangered, and sensitive plant species would be the
same as under Alternative 2.
CUMULATIVE IMPACTS
Current conditions of the vegetation and soils of the project area have resulted from many
management activities (other than livestock grazing) over time including timber harvest, recreational
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