Horses have a greater impact on rangeland vegetation than other ungulates because of their anatomy and foraging habits. Horses can consume 1.25 times the amount of forage than a cow of equivalent mass.
Myths and Facts
Equids evolved in the United States; therefore the current populations of horses in the United States are native.
The horses seen in the American West today are descended from a domesticated breed introduced from Europe, and are therefore a non-native species and not indigenous.Although many horse lineages evolved in North America, they went extinct approximately 11,400 years ago during the Pleistocene era. All horses (Equus caballus) and burros (E. asinus) now present in North America are descendants of those domesticated in Eurasia and Africa and thus subjected to many generations of selective breeding before they were introduced to North America by settlers.Exotic, non-native species are among the most widespread and serious threats to the integrity of native wildlife populations because they invade and can degrade native ecosystems. When invasive species are perceived as a natural component of the environment, the damages they inflict on native systems are overlooked. As a result, some groups advocate conservation and management of exotic species that promote their continued presence in landscapes where they are not native, leading to the decline of native species.The horses and burros that roam freely across areas of western North America and along parts of the Atlantic coast are examples of such species: they are iconic and beloved by some, but damage crucial wildlife habitat and require improved and sustainable management practices. The numbers and impact of these horses and burros can be difficult to control, amplifying their effects on native habitat and wildlife. In some cases, current management of horses and burros and their effects diverts resources (human and financial) from management of native species and habitat.
Horse and burro populations on Bureau of Land Management lands have not reached environmentally damaging levels.
Horse and burro population have surpassed the Appropriate Management Levels (AMLs) set by the Bureau of Land Management and their scientific team, and are damaging native plant and animal species.With federal protection provided by the Wild Free Roaming Horse and Burro Act of 1971, numbers of horses on public lands rose from approximately 17,300 in 1971 to an estimated peak of 57,200 in 1978. As of March 2015, the Bureau of Land Management (BLM) estimated that 58,150 – 47,329 horses and 10,821 burros – are roaming BLM-managed rangelands in 10 Western states. That number is more than double the West-wide Appropriate Management Level (AML) of 26,715, and likely a conservative estimate due to an 18-20% annual growth rate of the horse and burro population. AML’s, determined through an in-depth environmental analysis and decision process that includes public involvement, are set to ensure healthy rangelands that can support wildlife, permitted livestock, and wild horses and burros.The BLM monitors horse and burro population numbers and rangeland conditions. If the AML is exceeded for a herd management area, BLM calculates how many animals need to be removed from public rangelands to improve the health of the land.According to results from the Clan Alpine Mountains, differences in vegetation and small mammal activity can be observed between horse-excluded and horse-occupied areas when population numbers exceed established AMLs by less than 10 percent in the occupied areas. Areas inhabited by horses tend to have fewer plant species, less shrub cover, lower occurrence of native grasses, and more invasive plants. Many small reptiles and mammals that depend on burrows and brush cover to survive and breed are less abundant in horse-occupied sites. In particular, species that have specific habitat requirements are more at risk, while animals that thrive in disturbed landscapes, such as deer mice, become more common in areas occupied by horses.
Horses and burros cannot alter ecosystems.
Horse and burro populations that exceed Appropriate Management Levels are a distinct and serious threat to ecosystem health.Horses and burros damage landscapes by trampling vegetation, hardpacking the soil, and over-grazing forage plants. Horse grazing also leads to indirect damage by reducing the amount of precipitation that can penetrate the soil, increasing erosion, and increasing soil temperatures which leads to a shift in plant and animal communities. Areas inhabited by horses and burros tend to have fewer plant species, less vegetative cover, and an increased susceptibility to invasive plant species, which can have ecosystem-wide implications.Small reptiles and mammals in western North America that depend on burrows and brush cover to survive and breed are less diverse and less abundant in horse- and burro-occupied sites. These reptiles and mammals are an important component of rangeland systems, serving as a link in the food web and performing numerous critical ecosystem functions. The diet of horses and burros overlaps a great deal with that of bighorn sheep, and uncontrolled horse and burro populations have been predicted to lead to greater competition for forage and a decline in the populations of bighorn sheep and other native animals. Ecosystem-wide effects are of particular concern for sagebrush dependent species, including the Greater Sage-Grouse, which was recently considered for listing under the Endangered Species Act.Horses have a greater impact on rangeland vegetation than other ungulates because of their anatomy and foraging habits. Horses can consume 1.25 times the amount of forage than a cow of equivalent mass. Horses have both upper and lower front incisors and flexible lips, allowing them to crop vegetation closer to the ground than other ungulates. Horses also have hooves designed with one round toe, unlike other ungulates on the range, allowing them to paw vegetation out by the roots, killing the entire plant. All of these physical characteristics can delay the recovery of vegetation.
The Bureau of Land Management is sending horses to slaughter to decrease their population.
The Bureau of Land Management does not and has not sold or sent horses or burros to slaughter.Under the Wild Horses and Burros Act, euthanasia is identified as an appropriate management tool to reduce numbers of unadoptable horses. However, the Bureau of Land Management currently uses alternative options to euthanasia. Excess horses that aren’t adopted by the public are held in temporary or permanent enclosures.In an effort to ensure the humane treatment of horses and burros gathered from public rangelands and to increase public transparency of gatherings, the Bureau of Land Management announced four internal policy updates in 2013 to its National Wild Horse and Burro Program. One update limits the number of animals sold to an individual, group, or holding location over a six month period and specifies trailer requirements in an effort to prevent the sale of wild horses and burros to slaughter.
The Bureau of Land Management’s policies are driving horses to extinction.
The Bureau of Land Management ensures horse and burro population numbers do not drop below the sustainable level to maintain viable populations.The Bureau of Land Management (BLM) is attempting to reach the appropriate management level of 26,715 horses and burros on Western public rangelands, which is 31,000 animals less than the current Western population. The transfer of horses from the range to temporary or permanent enclosures is used to manage for a sustainable level that would decrease the negative consequences for horse health, native forage and fauna, and other multiple uses. BLM closely monitors herd population levels and genetics to ensure the population does not decrease below a sustainable level.
Horse populations will stabilize in a healthy and natural way if left alone.
There is no scientific evidence to support the idea that horses can limit their own population naturally.Since the native species of North American horses went extinct in the Pleistocene era, the western United States has become more arid and many of the horses’ natural predators, such as the American lion and saber-toothed cat, have also gone extinct, substantially changing the ecosystem and ecological roles horses and burros play.Because these animals do not have natural predators and their populations are capable of doubling every four years without management, horse populations can increase to a point where food will become limited, leading to starvation. This population crash would likely happen after the range ecosystem has been damaged beyond repair, after which noxious and/or exotic weeds could be expected to replace native grasses and forbs. This would negatively affect water, air, and soil quality, further impacting entire ecosystems, including humans and wildlife.
Horse populations typically increase by less than 10 percent every year.
The Bureau of Land Management’s recent population statistics as well as multiple peer-reviewed studies have shown that horse herds increase by approximately 20 percent every year.Horse populations often grow at rates of 18–25 percent per year, which means these populations have the ability to double in four years. Growth rate is dependent on three factors: fecundity, mortality, and survival. The high population growth rate of these horses is due to their high reproductive rate, the lack of natural predators to keep their populations in check, and the increased survival rate due to artificial aids such as manmade water supplies.
The Bureau of Land Management removes horses to make room for more cattle grazing on public rangelands.
The Bureau of Land Management removes horses and burros from public rangelands to ensure rangeland health.Removal of excess horses and burros by the Bureau of Land Management (BLM) from overpopulated areas is in accordance with multiple land-use mandates and protects natural resources and rangeland health. The effect of rangeland degradation is of particular concern for declining big horned sheep and sagebrush dependent species, including the Greater Sage-Grouse, which was recently considered for listing under the Endangered Species Act.Authorized livestock grazing on BLM-managed land has declined by nearly 50 percent since the 1940’s, and has declined on public rangelands by 30 percent since 1971 – from 12.1 million AUMs to 8.4 million AUMs in 2014. Meanwhile, the horse and burro population has increased from an estimated 25,000 in 1971 to a minimum of 58,000 on the range in 2015.
Horse gathers, especially those using helicopters, are harmful to the horses and should be prevented.
Roundups of horses do not affect behavior or reproduction of horses and are necessary to humanely maintain healthy, sustainable populations on rangelands.The American Association of Equine Practitioners (AAEP) determined that the Bureau of Land Management (BLM) horse gather practices are humane, efficient, and effective, and that after gathers, horses are in good condition and do not display signs of distress. The level of exhaustion following a gather observed by the AAEP task force was noted to be equivalent to the level of exhaustion exhibited by a domestic horse post workout or competition. No severe injuries requiring veterinary care were observed by the AAEP task during gathers and only 5% of horses experienced superficial abrasions. Section 1338 of the 1971 Wild Free-Roaming Horse and Burro Act authorizes BLM’s use of helicopters and motorized vehicles in its management of horses and burros. Studies have shown that horse gathers via helicopter have no deleterious impact on horse foraging, social behavior, or foaling success. Gathers are a necessary management practice as horse populations become unsustainable.
Two million wild horses roamed the United States in the late 1800s through early 1900s.
This number, used by many advocacy groups, was taken out of context and has never been and cannot be substantiated.The source of this number, used by many advocacy groups, is the book titled The Mustangs (1952) by J. Frank Dobie. This folklore author noted that no scientific estimates of wild horse numbers were made in the 19th century or early 20th century. His misunderstood quote is as follows: ”All guessed numbers are mournful to history. My own guess is that at no time were there more than a million mustangs in Texas and no more than a million others scattered over the remainder of the West.” Mr. Dobie’s admitted guess of no more than two million mustangs has over the years been transformed by many into an asserted “fact” that two million mustangs actually roamed America in the late 1800s/early 1900s.Regardless what the herd count may have been at the turn of the 20th century, more relevant are the questions of what Congress intended in passing the Wild Horse and Burro Act in 1971, and how many head the range can actually accommodate. Congress directed the Bureau of Land Management (BLM) to manage horses within the areas they inhabited at the time of the Act’s passage (herd areas). It also directed the agency to do so in a scientifically sound manner that allowed for the continued multiple-use of herd areas. Accordingly, the BLM established scientifically-derived appropriate management levels (AML), which it determined to be 26,715 for the total maximum population. This AML was determined to ensure that essential habitat components are present in sufficient amounts to sustain healthy horse and burro populations and healthy rangelands over the long-term, and that the herd size is sufficient to maintain a genetically diverse horse and burro population.