The Bureau of Land Management of the Department of the Interior needs to continue making changes to its Wild Horse and Burro Program, including stepping up its use of fertility control, taking additional measures to ensure the humane care of animals, and ensuring further program transparency.
These conclusions and more came from a National Academy of Sciences’ National Research Council committee report, “Using Science to Improve the BLM Wild Horse and Burro Program: A Way Forward,” released June 5. The committee was commissioned by the BLM, which requested the NAS to perform and prepare an independent assessment of numerous scientific issues related to the agency’s management of wild horses and burros on public rangelands in the western U.S.
The NAS study looked at issues such as population modeling, annual rates of population growth, fertility control methods, carrying capacity of various lands that support wild horse herds, genetic diversity in wild horse herds, and predator impact on wild horse population growth.
Among other things, the research committee found that most free-roaming horse herds on public rangelands in the western U.S. are growing at rates of 15 to 20 percent per year. A population growth rate of 20 percent per year results in a herd doubling in size in four years and tripling in six years.
Additional key findings included the following:
Management of free-ranging horses and burros is not based on rigorous population-monitoring procedures.
Current statistics on the national population size of wild horses and burros cannot be considered scientifically rigorous.
Management practices are facilitating high horse population growth rates.
The primary way that equid populations self-limit—increased competition for forage at higher densities—results in smaller quantities of forage available per animal, poorer body condition, and decreased survival rates.
The most promising fertility-control methods for application to free-ranging horses and burros are porcine zona pellucida vaccines, the GonaCon vaccine, and chemical vasectomy.
The Wild Horses and Burros Management Handbook lacks the specificity necessary to guide managers adequately in establishing and adjusting appropriate management (population) levels.
How appropriate management levels are established, monitored, and adjusted is not transparent to stakeholders, supported by scientific information, or amenable to adaptation with new information and environmental and social change.
Tools already exist for the BLM to use in addressing challenges faced by its Wild Horse and Burro Program.
The NAS research committee was chaired by Dr. Guy H. Palmer, director of Washington State University’s School for Global Animal Health, and included Dr. David S. Thain, an assistant professor and state extension veterinarian in the Department of Agriculture, Nutrition, and Veterinary Science at the University of Nevada-Reno.
“Science alone, even the best science, cannot resolve the divergent viewpoints on how best to manage free-ranging horses and burros on public lands. Evidence-based science can, however, center debate about management options on the basis of confidence in the data, predictable outcomes of specific options, and understanding of both what is known and where uncertainty remains,” Dr. Palmer wrote in the report.
“I am confident that this study provides a center point and hope that it will serve as a guide for the first step in the journey toward ensuring that genetically viable, physically and behaviorally healthy equid populations can be maintained while preserving a thriving, balanced ecosystem on public lands.”
The committee recommended that the BLM continue to build on its partnership with the U.S. Geological Survey to develop rigorous, practical, and cost-effective survey methods for population monitoring, which will help inform management decisions. The NAS committee further recommended that the BLM take into account the full variety of stakeholders, including local communities, in formulating its management plans. It also called on the BLM to provide greater specificity in its guidance to field managers regarding the establishment and adjustment of appropriate management (i.e., population) levels in its 179 Herd Management Areas across the West.
The report will help the BLM build on the reforms that the agency has taken over the past several years to improve program effectiveness, according to a June 5 BLM press release.
“The BLM shares the committee’s view that although no quick or easy fixes exist to this pressing issue, investments in science-based management approaches, exploring additional opportunities for population control, and increased transparency could lead to a more cost-effective program that manages wild horses and burros with greater public confidence,” said Neil Kornze, BLM principal deputy director, in the release.
The BLM will review the report with the National Wild Horse and Burro Advisory Board, which advises the BLM and U.S. Forest Service on the management, protection, and control of wild, free-roaming horses and burros on public lands administered by those agencies, according to the release.
Another report—generated by the American Association of Equine Practitioners BLM Task Force in August 2011—analyzed the BLM’s practices related to wild horses and burros. It came to conclusions that are similar to those of the NAS, saying the bureau had too many horses to manage, because more remain in captivity than run wild on the range. The task force also encouraged the BLM to prioritize research into, and application of, effective fertility control methods to reduce the foaling rate in wild herds.