Wednesday, September 12, 2007


This is not some new age Buddist chant. AUM stands for Animal Unit Month and is one of the most critical tools used by BLM in rangeland management. An Animal Unit Month (AUM) is the amount of forage one cow, one horse or five sheep will consume during the course of a month. Here are some things to know about AUMs:

Not All AUMs Are Created Equal
The amount of acreage required to create one AUM greatly depends on the area. If the area is lush, it doesn’t take many acres to provide enough food to sustain a cow, horse or five sheep for a month. However, in more arid regions it may take up to 30 acres or more to provide the forage necessary to sustain the same animals.

BLM managers take a section of public land and determine how much forage that environment can produce – this is the pie. Then they carve up the pie by giving some to wildlife, some to livestock, some to wild horses and burros and leave some alone in order to support healthy ecosystems.

The old standard for issuing forage allocations used to be 50% for all rangeland users and 50% was left untouched. New studies have determined that allocating only 35-40% is “In” for healthy rangelands.

When BLM removes wild horses and burros, it is because they are now consuming more pie (AUMs) than what BLM gave them when they were cutting up it up in the “planning process”. Usually BLM issues most of the pie to livestock and often gives only a sliver of AUMs to wild horse and burro herds. This causes them to always be called “excessive”.

Jackson Mountain Herd Management Area (HMA)
The photo used is a wild horse removed in January 2003 from the Jackson Mountain HMA located in Northern Nevada with the BLM removing more this August. The Jackson Mountains HMA spans 283,699 acres with an allowable management level not to exceed 217 wild horses or one horse per 1,307 acres.

Currently, the BLM is in the process of “carving pie” for the Happy Creek Livestock Grazing Allotment, part of the Jackson Mountain HMA. The old plan gave 3,724 AUMs to livestock and 720 AUMs to the Jackson Mountain wild horses. The new plan still gives 3,724 AUMs to livestock, includes a piece for each big game species but now provides no AUMs for the Jackson Mountain wild horses.

BLM is also proposing a new fence that is projected to cause “serious and irreparable impacts to the Jackson Mountain wild horses and their habitat” including entanglement, injury and/or death, lack of access to areas they historically grazed and loss of genetic viability by cutting them off from the rest of the HMA and any other wild horses.

Preserve the Herds by September 15, 2007
If you would like to help wild horses stay wild, drop BLM a line before September 15th and ask that the Happy Creek Grazing Allotment include AUMs (food) for wild horses too, not just livestock and big game. Also, since BLM knows the fence will be dangerous, ask them to find another solution that helps everyone, not just the few, and take pride in your participation to Preserve the Herds.

Heidi Hopkins, BLM Wild Horse & Burro Specialist, at
Or fax it to: (775) 623-1503
BLM Winnemucca Field Office
5100 East Winnemucca Blvd.
Winnemucca, NV 89445
Phone (775) 623-1500

If you do contact them, remember your personal info and comments become part of public record and may be accessed as part of the public information process.

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