While some may see wild horses as majestic symbols of the American West, these feral animals cause substantial habitat damage. Consider Sheldon National Wildlife Refuge in Nevada, which was established to provide habitat for pronghorn, mule deer, greater sage–grouse, pygmy rabbits and others.

The refuge has experienced the damage that feral horses can wreak. The refuge is full of sagebrush–dependent species native to its high–desert habitat—nearly 300 invertebrates, 235 birds and 76 mammals.

The horses on the refuge are descendants of domesticated animals turned loose. They damage habitat by grazing and trampling vegetation and streambeds. In 2008, then–project leader Paul Steblein studied more than 100 scientific papers about the effects of horses on the sagebrush–steppe ecosystem and concluded that “never have I found science so condemning.” He believes horses are the number one issue inhibiting the mission of Sheldon Refuge, an assessment corroborated by a panel of wildlife biologists and natural resource managers.

Current project leader John Kasbohm says habitat monitoring data from 2002 onward show that 44 percent of the refuge’s streams and 80 percent of its springs are severely degraded because of feral horse and burro activity. The soil becomes compacted and eroded, stream banks become unstable, species richness and plant cover are reduced, and cultural resource sites are trampled. Recent research shows horses are having similar impact on critical upland habitats.

Without controls, the horse population increases by 18 to 20 percent a year. Sheldon Refuge now has more than 800 horses and 100 burros. Sterilization has cut the foaling rate by more than two–thirds over the past six years, but that does not resolve the problem quickly enough to reverse the habitat damage.

The refuge’s 15–year comprehensive conservation plan (CCP) calls for removing feral horses and burros by 2017. The refuge is implementing that provision with particular care because of the horse’s iconic status.

Horse advocates range from those who want to leave the animals alone and let nature take its course to those who may be willing to work with the refuge to find homes in which to place the horses. The primary solution involves using helicopters to gather the horses for removal, and paying contractors or individuals to find long–term care for them.

“I came here knowing how to do partnerships and make sure people knew what we were doing and why. It’s hard to reach common ground,” says Kasbohm. “Most environmental groups support horse removal because they recognize the damage to refuges where wildlife is the primary mission.”

During public meetings and comment periods before the CCP was approved in September 2012, animal rights activists as well as wild horse and burro advocates expressed concerns about treatment of the animals during and after the gathering and the possible loss of the horses entirely. However, independent veterinarians are present during gather operations, and the refuge continues to work with known horse adoption contractors.

Even plans carefully designed to navigate the controversies can be problematic.

Sheldon Refuge received almost $1 million from a special U.S. Fish and Wildlife Service fund for large invasive species projects as well as matching funds and in–kind contributions from conservation partners. The refuge plans to gather 400 horses this summer and 400 next summer. But the price per horse to place them with an adoption contractor continues to increase. Kasbohm blames the drought–driven high price of hay and a market saturated with horses.

Now the refuge is partnering with horse advocates again, trying to find new adoption vendors and investigating a group that has offered to take 40 horses for free. “Unfortunately, we may have to take longer to remove the horses,” Kasbohm says.

In the end, Steblein says, “we recognize the stature of the horses. It’s an icon of the West. There’s a place for horses. Just not on a national wildlife refuge.”

Karen Leggett is a writer–editor in the Refuge System Branch of Communications.