Wild horses have clear impact on environment, but does the good outweigh the bad?

Silver said those horses are eating and trampling streamside vegetation in all of those forests, so much so that they even alter the hydrology of streams in some areas. 

Horse advocates argue that cattle do more damage to the soil than the horses do, as their cloven hooves dig deeper into the ground than horses’ more round and broad hoofs.

“It’s kind of like the difference in someone wearing snowshoes going over an area or someone just wearing stiletto heels poking right into the ground,” said Julie Murphree, a wildlife management professor at Arizona State University. 

Simone Netherlands, president of the Salt River Wild Horse Management Group, doubts a few hundred horses’ abilities to destroy tens of thousands of acres of land. 

“We’re worried about the environment too, but this is the most abundant forest. They could never eat it all if they tried," Netherlands said. “There are 7,000 elk there, 3,000 deer, 700 bighorn sheep, 200 antelope … wild horses are 4% of what lives in that forest.”

She said those animals, along with the 1.5 million cattle that graze on federal lands each year, do more damage than the horses.

Eric Thacker, a wildlife science professor and range management specialist at Utah State University, says just the opposite may be true. 

A 1,000-pound cow will eat about 25 pounds of forage per day, while an equally sized horse eats at least 25% more, he said. That’s because horses don’t digest as efficiently as cattle, so they need to eat more to get the same amount of nutrients. Put simply, the more vegetation they eat, the less remains as both food and habitat for other species. 

But because they don’t fully digest their food, many of the seeds they poop out remain viable for germination and are replanted, said California-based ethologist William Simpson. So in a way, horses act as a reseeding tool for the forest. He added that because horses have both upper and lower incisors — rather than cattle which have only lower teeth — horses chomp grass and leave the roots intact, whereas cattle destroy root systems as they pull grass up with their tongue.

Simpson, who studied biology and botany at Oregon State University before living among wild horses for nine years now, calls his method of studying and understanding horses "the Goodall method" because some of his colleagues, including Murphree, have referred to him as the "Jane Goodall of horses." He says the horses don’t belong in the Black River watershed, but not for the reasons given by most conservationists. 

“When you co-mingle horses with livestock, you’re actually doing the horses a big genetic disservice,” Simpson said. Because areas of land like the Black River watershed have been designated for livestock in the past, they’re typically nearly devoid of predators, as ranchers used to regularly hunt them to protect their cattle populations. Because of the low number of predators in those areas, he said, natural selection can’t run its course, causing eventual genetic decline.

Rather than leave the horses to compete for food and space with cattle and other herbivores like deer and elk, he believes the Alpine horses and horses in similar areas of contention should be relocated to what he calls “critical wilderness areas” — areas with low herbivore populations at higher risk of wildfires. As executive director of the Wild Horse Fire Brigade, he says the horses can be used to offset those risks and benefit both sides of the conflict. 

As large herbivores like wooly mammoths and horses went extinct around the end of the ice age, fire activity across North American grasslands increased. Because those herbivores weren’t there to mow down thick dry grasses, higher amounts of dry brush led to more intense fires. That’s why he and Murhphree, who also works for the brigade, want to use free-roaming horses to mitigate wildfires in particularly at-risk areas, mostly in northern California and Oregon.

Between the more than 60,000 horses currently in Bureau of Land Management holding pens and the 40,000 or so on the landscape, Simpson said the brigade could protect up to 20 million acres of land, though he said the number may be smaller depending on location, temperature and dryness. 

The idea has already been battle-tested, Simpson said. He thanked the presence of free-roaming horses for the mitigation of 2018 Klamathon Fire in Siskiyou County, California, which burned 38,000 acres for 16 days before reaching Simpson’s land and the surrounding community, which stayed fire-free. 

Not only do the horses protect the land from fire, he said, but they also save money in fire insurance and forest management. Perhaps most importantly, the plan would allow the horses to live and serve an ecological purpose rather than be rounded up and kept in holding pens.

“Everybody wins, and we save billions of dollars,” he said.

Arizona horse advocates would still rather see the horses remain in Arizona, where they serve as historical and cultural symbols of the Southwest. Netherlands said the horses can be equally valuable in mitigating wildfires in the Apache-Sitgreaves as they’d be in Northern California. But the Forest Service isn’t interested in managing any horses in the watershed, nor have they entertained Simpson’s ideas, regardless of what anti-wildfire function horses may serve.

“We’re not into the business of managing unauthorized livestock,” said Robert Lever, forest supervisor of the Apache-Sitgreaves National Forest. “We have an Endangered Species Act that we need to follow.”

It may not have to be all or nothing, though. Some range scientists say managing small populations of 100 or so can maintain environmental balance and please both sides of the endless conflict – but only if both sides can cooperate, something the Forest Service doesn’t show signs of wanting to do.

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