research topics and reiterated the necessity of a more thorough research program, as laid out in the Phase I report, to inform management decisions related to free-ranging horses and burros. The 1982 report completed the third phase of the study.

In 1985, the Committee on Wild Horse and Burro Research was asked to

  • Review research on wild horses and burros completed since 1982;
  • Assess the research recommendations of an earlier committee of the National Research Council in light of current issues, and update these recommendations if necessary;
  • Develop guidelines to assist the BLM in contracting for additional studies;
  • Monitor the progress of contracted research projects; and
  • Evaluate the final reports of the research projects and prepare a final committee report. (NRC, 1991, p. 1)

That committee recommended research topics and guidelines that were based on BLM’s identification of high-priority research. BLM funded research on two subjects: free-ranging horse population genetics and control of fertility in free-ranging horses. The National Research Council committee reviewed the research proposals that were submitted on those topics after a BLM request for proposals. BLM ultimately funded one project in each. The committee’s report, published in 1991, reviewed the design and results of the two projects. The study committee formed in 2011, the Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, was not asked to evaluate specific current research projects funded by BLM or to design research activities and then review the results. Instead, it was charged to use the previous reports and later relevant research to inform an independent evaluation of the science, methods, and technical decisionmaking approaches of BLM’s management program.


Although the Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program was not tasked with designing a research program or reviewing specific research projects, its statement of task echoed many of the issues addressed in the earlier reports. Like the committee that prepared the present report, the Committee on Wild and Free-Roaming Horses and Burros examined issues related to genetic diversity, fertility control, population estimates, population growth rates, forage use, and societal opinions. The Committee on Wild Horses and Burro Research looked specifically at the results of a free-ranging horse genetics study and a project on fertility control.

Genetic Diversity

The 1980 report flagged two management issues related to the genetic diversity of free-ranging horses and burros. First, it noted that a population that can sustain itself must have enough genetic variability to survive a multitude of environmental contingencies. Genetic information could be used to determine the size of a sustaining population for a given area that had particular environmental characteristics, and populations could be managed with that size as an objective. Second, the committee recognized that there was considerable disagreement about the origins of the free-ranging herds. One position held that the horses were the descendants of Spanish mustangs. Another took the view that the

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