Wild Horse Education reported earlier this week that the Forest Service has issued a decision notice authorizing a reduction of the AML for the Big Summit WHT, among other things, subject to a 45-day appeal period.
The number of horses allowed by plan would change from 55–65 to 12–57, necessitating a revision to the RMP. The limiting factor is winter forage. See “Purpose and Need for Action” in the EA, page 11 in the pdf.
The AML is the number of horses (or burros) an area can support after diverting most of the resources to privately owned livestock.
The horses will require 684 AUMs per year at the upper end of the new AML, while domestic sheep receive approximately 1,700 AUMs per year during a summer grazing season. The forage assigned to livestock would help the horses bulk up in the summer and be less vulnerable to winter conditions.
The low end of the AML is usually set at approximately 50% of the high end, to provide five years between roundups at a growth rate of fifteen to twenty percent per year.
But the project sets the low end at roughly 20% of the high end, allowing the herd size to be cut to the bone. This would set new precedent in wild horse management.
If the herd survives from a starting point of 12, how many years would pass before the population reaches 57? The growth rate at Big Summit is thought to be around 8% per year, according to “Current Conditions” in the EA (page 10 in the pdf).
Here is the mathematical relationship. Solve for x.
12 × 1.08^x = 57
The answer is 20.24—twenty years to reach the high end of AML. Throw in some contraceptives and the herd will basically flat-line, the dream of land managers and ranchers everywhere.