NEPA--Environmental Assessment
NEPA--Environmental Assessment
NEPA--Environmental Assessment
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Silverton Grazing Risk <strong>Assessment</strong><br />
bighorn summer range. Together, there is about 4,877 acres of overlap between these<br />
allotments and mapped summer range of the S33 herd. Within this area of overlap, about<br />
821 acres (17%) are suitable for domestic sheep grazing.<br />
West Needles Herd (S71):<br />
The S71 West Needles Herd was established with animals translocated from the<br />
Georgetown Herd in 2000, and 2002-2003. The 2007 estimated population size of the<br />
West Needles herd was 75 animals (George et al. 2008), and reproduction and survival<br />
have been good (Beecham et al. 2007). Bighorn sheep use the entire Animas River canyon<br />
from Rockwood up to Needle Creek. The primary summer range of this herd is the West<br />
Needle Mountains, and primary winter and lambing range is the Animas River canyon<br />
from Rockwood up to the Cascade Wye.<br />
Immediately after release, two bighorns dispersed into the S21 Ouray-Cow Creek herd.<br />
Based on ear tag observations, several sheep dispersed into the S33 Pole Mountain/Upper<br />
Lake Fork herd. Six or seven sheep moved into the Hermosa Cliffs area to the west of the<br />
Animas River canyon and have remained there and produced lambs every year.<br />
The CDOW opened S71 for hunting for the first time in 2007 with 1 ram tag issued<br />
annually. No ewe licenses have ever been issued for this herd.<br />
S71 is considered a translocated herd by CDOW and therefore is lower priority for<br />
conservation at a statewide level (George et al. 2008). As a translocated population,<br />
CDOW recognizes the existence of pre-existing domestic sheep grazing to the north, east,<br />
and west of S71, and does not advocate closure of active domestic sheep allotments on<br />
public land based solely on the potential for interaction between domestic and bighorn<br />
sheep (Colorado Division of Wildlife 2009). CDOW does however, suggest working with<br />
existing permittees grazing sheep in areas of mapped overlap with bighorn sheep summer<br />
range to collaboratively take advantage of opportunities if/when they arise to reduce the<br />
potential for physical contact, and the subsequent potential for disease transmission,<br />
between domestic sheep and bighorn sheep of the S71 herd.<br />
Under current management, the S71 bighorn herd overlaps with 6 active or vacant<br />
domestic sheep allotments. Of these, 5 are FS allotments: West Lime (vacant), Little<br />
Molas/West needles (vacant), Needles Mountains (vacant), Flume (vacant), and Deer<br />
Creek/Engine Creek (active). One active BLM grazing allotment, Gladstone, overlaps with<br />
mapped summer range for S71. Together, there is about 36,554 acres of overlap between<br />
these 6 allotments and mapped summer range of the S71 herd. Within this area of<br />
overlap, about 9,464 acres (26%) is suitable for domestic sheep grazing.<br />
ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER ANALYSIS<br />
We considered the possibility of moving domestic sheep bands from currently active<br />
allotments where the perceived risk of contact with bighorn sheep is “High” (see figure 3,<br />
below) to other currently vacant allotments where the perceived risk of contact with<br />
bighorns may be lower. Below is a brief discussion of the alternatives considered but<br />
eliminated, and the reasons for their elimination.<br />
Graysill and Flume allotments (FS, vacant allotments): These allotments have been vacant<br />
since 1989. They have been successfully used as a forage reserve as recently as 2002 with<br />
no adverse impacts to vegetation and soils. There are few if any conflicts with recreation.<br />
There is a small area of overlap with mapped summer range of the S71 West Needles<br />
bighorn sheep herd in the extreme south end of the Flume Allotment. Due to difficult<br />
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