The Piceance-East Douglas HMA covers 190,130 acres in northwest Colorado, including 158,310 acres of BLM land, 5,330 acres of state land and 26,490 acres of private land, according to Section 1.1 an EA from 2011. Ownership is denoted by tan, blue and white, respectively, in the following map.
The largest section of private land is at the south end of the U-shaped HMA.
The old EA was incorporated by reference into a new EA for resource enforcement actions in and around the HMA. The Proposed Action, featuring roundups and fertility control, is discussed in Section 3 of the new EA. Supporting documents can be found in the project files.
The number of horses allowed by plan is 235 and the stocking rate allowed by plan is 1.2 wild horses per thousand acres. The forage requirement is 2,820 AUMs per year, so the land must be able to produce at least 14.8 AUMs per year per thousand acres.
The HMA intersects four allotments. Table 3-14 in the old EA provides the total acreage inside the HMA for the public portions only. Map 3-4, reproduced below, shows the allotments but does not distinguish between public and private lands.
However, Map 3-5 does. Pastures on the west end of Yellow Creek and Square S overlap the private area, along with a small portion of Cathedral Bluffs, suggesting that the HMA is 100% subject to permitted grazing
Although the total area available to livestock inside the HMA may be 190,130 acres, neither EA provides data for the private portions of the allotments. Therefore, the following calculations will be based on the public portions only.
Allotment sizes and active AUMs were taken from the Allotment Master report in RAS.
Allotment acreage, grazing seasons and forage amounts inside the HMA were developed from data in Tables 3-14 and 3-15 of the old EA, updated per the Authorization Use report from RAS.
Land in the Greasewood allotment must be able to produce at least 1,569 ÷ 27,810 × 1,000 = 56.4 AUMs per year per thousand acres to support livestock grazing in that area. Forage production rates in the other allotments are of similar magnitude, exceeding the rate for horses by an appreciable margin.
The total authorized forage for livestock on public lands inside inside the HMA is 6,840 AUMs per year. If the private areas were included, the number would likely be higher.
The Greasewood permittee would have to place 603 cow/calf pairs in the allotment to graze off 1,569 AUMs in a 2.6 month grazing season. The total estimated number of cow/calf pairs on public lands inside the HMA is 4,800. The overall stocking rate is 4,800 ÷ 166,888 × 1,000 = 28.8 cow/calf pairs per thousand acres.
The weighted average grazing season inside the HMA is 1.4 months per year.
These figures are compared in the following charts.
Although the grazing season is short, cattle are turned out at a high stocking rate, perhaps mowing down everything in sight, which would explain why the horse population must be held to such a small number.
The HMA is managed primarily for livestock, with the horses receiving just 29% of the authorized forage, neglecting wildlife.
The forage assigned to livestock would support an additional 570 wild horses, for a True AML of 805.
The current population, estimated to be 838, includes 33 excess horses, not 603.
“The need for a roundup and fertility control program is not as great as we originally thought.”
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