Maintaining Range and Herd Health
How wild horses and burros are managed differs from how most other species are managed on public lands. Wildlife species, such as deer, are usually controlled through a combination of hunting and natural predators. Livestock use on public lands is intricately managed and controlled through grazing permits. Because wild horses and burros are protected from hunting, and because of a lack of natural predators, if left unmanaged herds can double in size in just four to five years and quickly outgrow the ability of the land to support them. Maintaining herd size at the appropriate management level is the best way to ensure healthy horses and burros on healthy rangelands.
What is Appropriate Management Level?
To protect the health of the land and to support healthy horses and burros, the BLM works to achieve in each HMA what is known as the Appropriate Management Level (AML) – the point at which wild horse and burro populations are consistent with the land’s capacity to support them and other mandated uses of those lands, including protecting ecological processes and habitat for wildlife and livestock.
The AML for each HMA ranges from a minimum population level to a maximum population level in order to allow for population growth over a four- to five-year period. The BLM establishes an AML through the evaluation and analysis of rangeland resource and population data spanning several years, including data relating to vegetation and soil types, weather and water quality. The AML for each HMA is set in an open, public process through field office planning efforts.