Rewilding with Wild Horses

© Liz Koonce

No one living in the American West in the past twenty years could have avoided hearing about the scandals and political issues surrounding wild horses on public lands. Wild horses have been removed from the public range to prioritize livestock grazing interests. As of March 2021, the Bureau of Land Management reported that there were 52,832 “excess” wild horses and burros held in off-range government holding facilities at a cost of approximately $50 million a year. But what if there was an elegant solution to this problem? There is a means of both restoring public lands and humanely managing wild horses, while mitigating some carbon to boot.

Rewilding and carbon mitigation go hand in hand, and the largest potential biome for rewilding is the world’s grasslands, which cover 25% of the planet’s land surface. Horses are considered mesograzers, which are classified as species with the highest per capita potential to shape climate change drivers. Wild horse herds affect ecosystem nutrient transportation, landscape fire regimes, and vegetation mosaics, while emitting far less methane than cattle and sheep due to their classification as hind-gut fermenters rather than ruminants. Many rewilding programs in Europe use feral horses as part of their rewilding practices. The introduction of horses in rewilding projects has been found to increase biodiversity and maintain or preserve natural grassland mosaics, increasing their suitability for other species.

As ecosystem engineers, horses create beneficial changes through their physical actions. In the winter horses break ice with their hooves, allowing other species access to water, and in the summer dig to create small water catchments, creating intermittent riparian habitat for desert species. Large-scale herd movements in deep snow may also reduce snow insulation in northern landscapes, leading to an increase in permafrost freezing, potentially mitigating methane loss and woody plant encroachment. Horse’s unique single-unit or soliped hooves can loosen topsoil as they move across the landscape in high-intensity short-duration grazing bouts. This nomadic soil loosening, combined with their moisture-rich dung, can increase carbon sequestration in soils and promote nutrient cycling.

Popular on Rewilding.org

America’s Red Rock Wilderness Act: Moving America Closer to 30×30 and Enhancing Wildlife Connectivity

Wild horses have other interesting effects on the ecosystems they inhabit simply by existing within them; by trampling certain vegetation and wallowing near water mustangs can create microhabitats and redistribute nutrients through seed dispersal. Plant species richness and pollinator populations have been found to be higher in areas grazed by horses compared to ungrazed areas and can even mitigate the decline of pollinator-dependent plants. Horse feces, in addition to spreading seeds, builds the humus layer of soils and increases soil’s absorption of water, lowering wildfire risk. These characteristics are unique to horse feces compared with ruminants such as cattle, sheep, goats, or deer. Wild horses in the United States have also been shown to commonly graze on invasive cheatgrass.

© Liz Koonce

Horse herds use their ranges heterogeneously, with daily and seasonal movements over large tracts of lands. These wide-spread movements are confined to narrow trails throughout the landscape, which are frequently used as travel routes by many species of wildlife. In a single study, remote cameras recorded movements on horse trails of moose, mule deer, gray wolf, mountain lion, Canada lynx, and others. In more vegetative understories, these trails also create more diverse forest conditions of wind and light exposure, allowing for a greater diversity of plant and animal species to fill in niches. In cold seasons, herd movements open trails through snow, letting smaller animals move through the environment more easily.

One of the purported reasons that the Bureau of Land Management gives for removing wild horses from public rangelands is the false narrative that horses have no natural predators. Data shows otherwise. In the Montgomery Pass Wild Horse Territory on the border of California and Nevada, where a population of five individual mountain lions lived, the population of free-roaming horses was significantly influenced through foal predation. The average yearly number of foals killed by mountain lions was 13.5, which was 45% of the foals produced. In this case, cougar predation on foals was sufficient to strongly limit the growth of the wild horse population and had beneficial stabilizing effects on wild horse numbers. Similarly, a healthy wild horse population in British Columbia, located in a wilderness area in which all top North American predators also thrived, was found by researchers to have minimal signs of range degradation and small herd sizes of 20–30 individuals each, without outside management by governing bodies or herd removal. Other studies have confirmed that foal predation from mountain lions effectively limits population growth. A wildlife refuge manager in Arizona even referenced mountain lion predation as a reason for removing a genetically unique herd of Spanish mustangs from a newly obtained property; “It’s pretty obvious that lions are taking some of the colts; that’s why we think it’s important to get them off the refuge as quickly as possible.” The herd was 100 animals strong, and encroaching development and land sales had pushed them onto a small acreage which was overgrazed.

Government predator control programs eliminated wolves and grizzly bears in the west and continue to target mountain lions and coyotes. The complicit relation of government agencies and livestock interests has led to the direct destruction of most predators on public lands, yet there are no current programs focused on predator reintroduction or population growth on public lands or Herd Management Areas where they might control wild horse populations. The multi-use status of most of the Herd Management Areas on public land as grazing allotments is detrimental to the possibility of natural predator-prey interactions limiting horse populations in most areas. Livestock grazing directly affects cougar numbers, because depredating individuals may be killed, and stock also may compete with native ungulates, thereby influencing predation patterns on native prey. Wolves are also often killed by livestock owners, to protect sheep, goats, or young cattle from possible predation. Interestingly, in a study on a population of wild horses in Canada, local interviewees reported that wolves preyed on free-roaming horses and observed wolves to preferentially prey on horses over cattle in surrounding areas.

© Liz Koonce

Another reason given by the BLM for the continued removal of wild horses from public rangelands is their status as a non-native species. There are three dominant theories of the native classification of wild horses;

(1) That the species originated in North America, spread to Europe, then went extinct in its homeland before being reintroduced as a domestic species in the 1400s and is therefore a genetically native species reoccupying the vacant niches of the North American prairie;

(2) That the species originated in North America, spread to Europe, then went extinct in its homeland before being reintroduced as a domestic species in the 1400s and is therefore an invasive species;

(3) That the species originated in North America, spread to Europe, and continued to exist in the Americas in reduced numbers well past the end of the Pleistocene era, then interbred and hybridized with domestic horses which were brought over by colonists in the 1400s, increasing their numbers.

In all of these theories, there is no debate that horses originated in North America between 4 and 4.5 million years ago. There is a saying amongst several plains First Nation tribes; “The grass remembers the horses.” As a keystone species in the grassland ecology of the prehistoric continent, horses thrived and spread from North America to other continents. According to the dominant Western historical perspective, horses eventually died out in their homeland near the end of the Pleistocene along with much of the other megafauna of the American plains. This major extinction was allegedly triggered by early human hunting and climatic changes. In contrast to this widely accepted history, several first nation tribes allege that the aboriginal North American horse survived through the end of the Pleistocene and were integral to the pre-colonial contact culture of Great Plains tribes. This claim is backed up by petroglyphs of wild horses dated hundreds of years prior to Columbus’s arrival and the more commonly accepted time that horses were reintroduced to the continent between 1493 and 1540.

Still, in mainstream science, the arrival of horses back to their ancestral homeland is attributed to Columbus and other Spanish explorers, who bred horses in their missions and colonies, spreading the species across the plains. Today, the United States subscribes to the theory that considers mustangs to be an invasive species, rather than a native species returning home to fill a vacant niche, and their management and status within the regulatory bodies of the government is indicative of this classification.

© Liz Koonce

There are currently little to no public amenities or infrastructure relating to the wild horse herds on American public lands. Many residents of states which are home to wild horses are shocked to hear that herds exist there and are even more surprised to hear that they are on public land and can be sought out. With the proper infrastructure in place, what parents of a horse-obsessed young girl would deny her a weekend trip to attempt to spot a wild mustang? Given a choice between a regular BLM campground and one on a landscape where wild herds roam, what couple wouldn’t jump on the chance to camp where they could see stallions sparring at dawn?

Wild horses are a cultural touchstone for connecting the public with our public lands. Designing these landscapes while using wild horses as both rewilding engineers and a draw for visitors would create a non-consumptive use on public lands which could replace the consumptive uses of livestock grazing, timber harvesting, and mining that currently occupy and degrade them.

As the concept of ecological restoration has become integrated into North American culture in recent years, landowners and managers are beginning to seek out more and varied alternative management and restoration methods. Rewilding with wild horses in the United States represents untapped potential for revenue, environmental benefit, and a solution to the dilemma of maintaining horses in holding facilities. A government program offering financial incentive or tax breaks to landowners who host small herds of gathered mustangs on their properties for periods of 5 to 10 years with the goal of rewilding degraded agricultural land would benefit landowners, the BLM, the environment, and wild horses. Embracing wild horses as ecosystem engineers and allowing them to naturally rewild our public and private lands rather than removing them to allow space for cattle, would connect the public with our wild spaces, increase the health of our public lands, and restore our precious grassland ecosystems.

If you would like to advocate for keeping wild horses a part of the ecology of our public lands, please visit the American Wild Horse Campaign’s website.

Editor’s note: The Rewilding Institute remains open-minded on the question of whether and where wild horses, mustangs, may belong in North America. Whatever your view on this controversial issue, your feedback is encouraged. For an alternative perspective on this issue read “No to Feral Horses” by George Wuerthner, where he urges that we recognize wild horses in the American West as a non-native species that ought to be removed.

Liz Koonce

Liz Koonce holds a Master’s Degree in Landscape Architecture and a Bachelor’s of Science in Psychology. Her research thesis, “The Grass Remembers the Horses,” focused on the management of mustangs on public rangelands in western states. She has lived in Oregon, California, Nevada, Virginia, Singapore, and the United Kingdom, but her strong roots in the American West keep her coming back for more. She has camped and hiked extensively in every western state, where her relationship with the landscape has evolved through her understanding of the environment’s history. Liz currently lives in southern Oregon, where she is working on a nonfiction book.