The Forest Service announced last month that there were too many wild horses on the Big Summit WHT and that the land was deteriorating as a consequence.
A new approach is needed “…to ensure wild horses are managed in a thriving natural ecological balance with other uses…,” according to the Environmental Assessment for the new management plan (page 11 in the pdf file, emphasis mine).
The high end of the AML would be reduced from 65 to 57 under the proposed action, limited mostly by the availability of winter forage. The low end would drop from 55 to 12, opening the door to population control measures such as genetic dilution, sex ratio skewing and contraception.
The WHT contains 25,434 acres. The current AML yields a stocking rate of 2.6 wild horses per thousand acres. The stocking rate under the proposed AML would be 2.2.
The 57 horses allowed by plan would require 684 AUMs per year.
The horses share the land “…with wildlife and seasonally with domestic sheep; there are no permitted cattle,” according to page 10 of the EA.
The WHT intersects one grazing allotment, which is managed for two pastures. Table 21 supplies the acreage, forage allocations and grazing seasons. Map is on the next page.
Approximately 9,000 allotment acres fall outside the WHT. The WHT lies almost entirely within the allotment. Table 21 doesn’t give the percentages of the pastures inside the WHT so they were estimated to be .738, which makes the allotment acreage falling within the WHT is almost as large as the WHT.
Herd sizes and stocking rates for horses can’t be compared directly to those for sheep, at least from a resource viewpoint, so cattle will be used as a proxy. The forage demand of one wild horse is said to be equivalent to that of one cow/calf pair.
The stocking rate allowed by plan on the WHT is 19.3 cow/calf pairs per thousand acres (490 ÷ 25,415 × 1,000), compared to 2.2 wild horses per thousand acres.
The 57 wild horses allowed by the new management plan represent 10% of the grazing animals on the WHT during the summer season (57 ÷ [57 + 490] × 100).
The horses receive 29% of the forage, with the balance going to livestock. These figures are compared in the following charts.
The problem is not lack of winter forage but scarcity of summer forage. The horses can’t put on enough weight for the winter and their numbers have to be carefully monitored because most of their food has been diverted to privately owned livestock.
Never mind that the land was set aside for the horses.
The population controls lock the pattern in, guaranteeing the problem goes on forever.