NEPA--Environmental Assessment

Silverton Grazing Risk Assessment
Remaining Allotments (BLM and FS):
The 5 remaining allotments in the Silverton Landscape are Red Mountain (FS - active),
Elk Creek (FS and BLM - active), Deer Park (FS and BLM - active), Graysill (FS - vacant),
and Silverton Watershed (FS - closed). There is no overlap in any of these allotments with
mapped bighorn sheep summer range. All allotments are well removed from mapped
bighorn sheep summer range. For these reasons, the rating would be “Low Risk” for
contact between domestic sheep and bighorn sheep in Red Mountain, Elk Creek, Deer
Park, Graysill, and Silverton Watershed allotments.
RESULTS
Risk Rating: Alternative 2 – Low
Alternative 3 – Low
Of the 15 allotments analyzed in the Silverton Landscape EA (see Table 2, below), 8
overlap with mapped bighorn sheep summer range (see Figures 1 and 2, below). Under
Alternative 2, current management, 6 of these 8 allotments were rated as having “High
Risk” for contact with bighorn sheep, including the vacant allotments if they were
restocked (see Figure 3, below). The remaining two allotments with overlap were rated as
“Low Risk” due to site specific factors (see Figure 3, below).
Under Alternative 3, the three active allotments having overlap with bighorn sheep
summer range would all receive a rating of “Moderate Risk” (see Figure 4, below). These
allotments are: Engine Creek/Deer Creek (FS), Eureka/California Gulch (BLM), and
Picayne/Mineral Point (BLM). The two allotments with a “Low Risk” rating under
Alternative 2 would remain “Low Risk” under Alternative 3 These allotments are:
Gladstone (BLM), and Flume (FS). The three allotments with a “High Risk” rating under
Alternative 2 that would be closed under Alternative 3 would receive a rating of “Low Risk”
under Alternative 3. These allotments are: Little Molas/West Needles (FS), Minnie Gulch
(BLM), and Needles Mountains (FS).
Of the 7 remaining allotments that do not overlap with mapped bighorn summer range, 5
are rated as “Low Risk” for contact under both Alternative 2 and Alternative 3 (see Figures
3 and 4, below). These allotments are: Red Mountain (FS), Elk Creek (FS/BLM), Deer Park
(FS/BLM), Graysill (FS), and Silverton Watershed (FS). Of the final two allotments, one
allotment is rated as “Moderate Risk” for contact with bighorn sheep under both
Alternative 2 and Alternative 3 (Maggie Gulch, BLM), and the second is rated as “High
Risk” under Alternative 2 and “Low Risk” under Alternative 3 (West Lime, FS).
Under Alternative 2, current management, there is a total of about 41,430 acres of
overlap between active and vacant domestic sheep grazing allotments and mapped
bighorn sheep summer range in the Silverton Landscape. Of these overlap areas, about
5,639 acres are in active allotments, and 35,792 acres are in currently vacant allotments
(see Figure 1, below). Under Alternative 2, about 40,430 acres of overlap would occur in
allotments rated as “High Risk” for contact between domestic sheep and bighorn sheep
(see Figure 3, below).
Under Alternative 3, only about 7,105 acres of overlap would remain between active and
vacant domestic sheep allotments and bighorn sheep summer range. Within these 7,105
acres of overlap, about 6,132 acres would be rated as “Moderate Risk” for contact, and
973 acres would be rated as “Low Risk” for contact (see Figure 4, below). Under
Alternative 3, no acres of overlap would remain in “High Risk” areas.
D-22