Wildness in bison is maintained by evolutionary agents like harsh weather, native predators, competition for forage and mating. Photo George Wuerthner
Many bison advocates assert that bison have been “saved” from extinction because approximately half a million animals are now found in zoos, ranches, tribal reservations, state parks, national parks, and other public lands. Bison are not in danger of extinction.
However, most of these herds are domesticated and gradually losing their wildness. All bison herds have suffered some degree of domestication. The issues are not the number of bison but the quality of the bison and the question of domestication.
Domesticated bison herds are analogous to fish hatcheries, where research has documented significant genetic and behavioral changes that occur with domestication.
Hatchery fish are artificially bred and raised in controlled environments, with specific selective pressures removed, such as female choice and male-to-male competition. Hatchery fish are also more likely to have diseases and are generally less fit for survival.
Nevertheless, by occupying the same space and habitat as wild fish, hatchery fish increase competition for food and may increase exposure to predators and other impacts. These findings are one reason the state of Montana Fish Wildlife and Parks Department gave up fish stocking in rivers decades ago.
A synthesis that looked at the effect of hatchery fish around the globe found that hatcheries harmed wild fish 70 percent of the time. One study in Oregon found genetic changes in hatchery fish after just one generation.
Hatchery fish production degrades wildness. Hatchery fish are less fit for survival in the wild. Photo George Wuerthner
The bottom line is that domesticated fish are less able to survive in the wild, while harming the existing wild fish at the same time. Hatchery fish also create the illusion that salmon, trout, or other species are being “saved” from extinction, but, in reality hatcheries destroy the wildness of fish.
All of the bison herds in the U.S. are hatchery animals—giving the illusion that bison are being saved from extinction.
WHAT IS A WILD BISON
Wild bison are subject to evolutionary selective factors such as predation, mate competition, availability of forage and water, disease, and severe weather. These selective factors determine an individual’s fitness and which individuals are best adapted to their environment.
Mobility is one of the major attributes of wild bison. Bison need landscapes big enough to preserve mobility as a wild trait. Photo George Wuerthner
Mobility is the major adaptive feature of bison, thus, large landscapes are necessary to preserve wildness.
The least “farmed” U.S. herds are found in Utah’s Henry Mountains, South Dakota’s Wind Cave National Park, Utah’s Book Cliffs, and Yellowstone National Park. In particular, the Yellowstone N.P. herd and the Grand Teton N.P. herd hold the most “wild” bison of all because native predators still influence them. Nevertheless, ongoing policies like test and slaughter, tribal hunting, and other measures are reducing the wildness of bison.
Domesticated bison typically experience fewer selective factors or their ability to adapt are mitigated to some degree. Domestic bison are often fed in the winter; there are few or no predators; they are vaccinated against disease; and breeding may be manipulated by human selection. They are often culled. Fences, hunting, and other factors also inhibit the free-roaming nature of wild bison.
Yellowstone’s bison are the most genetically intact bison in the United States. Photo George Wuerthner
Most domesticated bison herds also share genes with cattle. There are few genetically pure bison left in the West. The Henry Mountains bison are among the few without genetic integration with cattle. According to the latest research, Yellowstone’s bison are the most genetically intact bison, with over 99.7 percent genetic purity.
As bison advocate Jim Bailey wrote before his death, “Wildness will be retained only in large wild places where natural selection operates.”
What we see across the spectrum is bison being domesticated. Sometimes rapidly and, in other instances, more slowly. But in all instances, even in Yellowstone National Park, bison are losing their wildness. They are becoming “hatchery bison” with the same deleterious effects as are experienced by hatchery-raised trout or salmon.
Nearly all the existing bison herds on ranches, tribal lands, and state and national parks are inadequate for retaining wildness. At present, only Yellowstone National Park comes close to meeting the requirements of a large landscape where bison wild genes can be maintained.
Wildness is lost to the degree that human manipulation influences bison survival. The greater the degree of human intervention, just like hatchery salmon, the more rapid the loss of wildness.
Even though Yellowstone retains the “wildest” bison left in the lower 48, current management practices still erode wildness. The annual culling of bison for slaughter by the National Park Service and the slaughter of bison by tribal entities when the animals leave the Park, even the harassing of bison to keep them from being killed, are slowly destroying the bison’s wild genome.
Tribal hunters gutting a bison killed just outside of Yellowstone Park. Tribal hunting degrades the wildness of Yellowstone bison in multiple ways. Photo George Wuerthner
The bison being killed are those with the instinct to migrate and are the first to be shot when they stray outside the Park. The hunters, rather than selecting animals that are weak or old as native predators would do, kill all age classes of bison in an unnatural selection.
The hunter’s destruction of older female bison, typically the herd’s leaders, removes cultural knowledge of how to survive in the landscape—things like where it’s safe to give birth or where to cross a river, and other cultural knowledge passed on from generation to generation.
The loss of bison from the park ecosystem also has impacts. A dead bison is a huge windfall for a grizzly or wolf, not to mention other predators, from coyotes to ravens. The removal of bison also reduces the influence of their grazing on plant communities. Bison are a keystone species that has a disproportionate impact on ecosystems.
While human predation on bison existed in the past, it was different from today’s hunter who chase bison with ATVS, use high-powered rifles, and removed the animals carcasses with pickup trucks. To the best of oour knowledge, bison have no adaptative strategies to counter such predation influences.
For millennia, groups of bison were killed with buffalo jumps or occasionally by hunters on snowshoes who would capture bison in deep snow. But such predation pressure had little influence on the overall bison populations.
Once tribal adoption of the horse occurred in the 1700s, it changed Indian predation and related cultural practices. The ability to track and kill more bison led to human population growth, more intertribal wars, and more mobility of Indian people. The mounted hunter because in effect a new super predator. With the augmented ability to find bison, slay bison and utilize bison in trade. Horse mounted tribal hunters were one of the major influences leading to bison destruction across the West.
None of these impacts are acknowledged by the agency people, the tribal hunters who annually slaughter of bison, or their conservation advocates like the Greater Yellowstone Coalition, National Parks and Conservation, Sierra Club, and others who put treaty “rights” ahead of what is good for bison.
HOW DO WE PRESERVE WILDNESS
The first goal of wild preservation is retaining a large enough population across a large landscape for genetic diversity. Larger populations are less likely to suffer from genetic losses.
Yellowstone bison are subject to harsh winters, forage competition, native predators, and other influences that maintain their “wildness.” Photo George Wuerthner
All bison in the U.S. are descended from very few individuals. The Yellowstone bison, for instance, started with approximately 25 individuals. This means the herd began with a bottleneck of limited genetic diversity. This loss of gene diversity is especially pronounced in bison since one bull may breed 10-20 females, significantly reducing the possiblity for varied genetic contribution to the resulting calves.
Small populations suffer from genetic inbreeding, genetic drift, and bottlenecks which are the reasons why we need to aspire to larger bison herds than exist today.
Although estimates vary, the few authorities on bison genetics believe a minimum of 3,000 animals is necessary to retain sufficient genetic diversity. However, other authorities have told me that 10,000 animals are essential in the long run (100 years). A metapopulation of 10,000 could be maintained in the Yellowstone ecosystem by establishing additional interbreeding herds on adjacent national forest lands.
Yellowstone National Park’s draft EIS on bison management has some positive aspects in that regard, including the proposal to stop bison capture, testing, and slaughter in the Park. However, the DEIS proposes that tribes slaughter more bison on the park border for cultural reasons. Cultural values are not the same as biological values.
Among the problems associated with tribal hunting adjacent to Yellowstone is the indiscriminate killing entire family groups, by tribal hunters. Such behavior by tribal hunters changes the age structure and sex ratios in bison herds. Bison herds living with native predators like wolves and bears tend to have older mean ages since native predators tend to remove calves and yearlings. Prioritizing tribal bison kill will only lead to a greater loss of bison wildness.
Bison behavior is also influenced by a dominant and subdominant hierarchy. For example, dominant cows have access to more forage of high quality than subdominant cows. These relationships are disrupted by the indiscriminate culling by tribal hunters or by agency test and slaughter measures.
“Conservation bison” at the National Bison Range are culled annually, forced to move from pasture to pasture, and in other ways being domesticated. Photo George Wuerthner
“Conservation” herds like those at the National Bison Range stabilize bison numbers at a pre-determined level by culling “excess” bison. Conservation herds might sound like a good thing, but most are still managed like livestock.
Wild bison, which may reach a carrying capacity level, are forced to compete for forage, space, and water. This results in the selection for aggressive individuals who may have greater adaptation to cold, perhaps more efficient digestion, and other traits. Even Yellowstone N.P.’s bison herd is managed for an artificially set population goal, which can negatively impact bison diversity.
Wild bison herds have a natural 50/50 distribution of male to female. Breeding competition is intense; only the fittest bulls do most of the breeding. In smaller herds found on “conservation herds,” ranches, or tribal lands, the tendency is to control breeding access to a few bulls artificially, thus further reducing genetic diversity.
PRESERVATION OF WILDNESS
If society wishes to preserve wildness in bison, we must radically change how bison are treated. Even the best so-called “conservation” herds on state or federal lands, like the animals at the National Bison Range, are domesticated.
The best opportunity for retaining wildness in bison are the herds in Yellowstone National Park. However, even these animals are subject to artificial selective pressures.
The state of Montana relies upon brucellosis, a disease that can cause abortion of fetus in cattle, as the cudgel or excuse to keep wild bison hemmed in the Park and adjacent land. The state of Montana has made it illegal to transport bison in the state and has given the counties have the power to veto bison restoration.
Test and slaughter by the NPS require the capture of bison within the Park. If bison happen to avoid capture in the Park, they are often killed by tribal members as soon as they wander outside of the Park boundaries. In all such instances, there is removal of bison biomass from the ecosystem which affects bison wildness and harms the Yellowstone ecosystem. These practices should be terminated. Bison should be permitted to move outside the Park to other federal lands like other wildlife.
Expansion of bison to suitable habitat throughout the Greater Yellowstone Ecosystem can create a meta population large enough meta population to ensure wildness. Photo George Wuerthner
Expanding Yellowstone bison numbers outside of the Park is one of the best ways to ensure wildness. Creating a metapopulation of interbreeding bison within the Park and on adjacent national forest lands could go a long way towards retaining wildness.
The creation of other wild herds is also necessary. Yellowstone bison could be transferred to the Charles M. Russell National Wildlife Refuge and surrounding BLM lands along the Missouri River in central Montana. The American Prairie Reserve contemplates a 3 million acre area dedicated to bison restoration which would surround the existing public lands base in Central Montana.
The Oregon Buttes in Wyoming’s Red Desert. The Red Desert is the largest unfenced area in the United States and a suitable place for restoration of wild bison. Photo George Wuerthner
Wyoming’s Red Desert region is the largest unfenced area in the U.S. and well within the historic range of bison as is the Upper Green River near Pinedale. The establishment of wild bison in this region is another possibility.
CONCLUSION
The Public Trust Doctrine demands that bison be managed for the benefit of all citizens. One can’t be promoting wild bison while at the same time advocating for policies that reduce evolutionary influences. Such influences would include competition for forage in harsh winters or for mates, changes in age and population structure, removal of individuals prone to migration, or elimination of bison who can intimidate predators. Beyond that the removal of bison from Yellowstone herds negatively affects other species that consume dead bison and or the plants that are influenced by bison grazing behavior and distributon.
So-called advocates for bison like the Buffalo Field Campaign, tribal groups, the National Park Service, and many conservation organizations like the Greater Yellowstone Coalition, National Parks and Conservation, among others, all promote tribal slaughter of bison outside of the Park. At the same time, they suggest they value wild bison. What they are promoting is hatchery bison, not wild bison, and they are culpable in the gradual domestication of the bison genome.
The Missouri River flows through the Charles M. Russell NWR in central Montana. Photo George Wuerthner
We need to expand the opportunities for bison recolonization of public lands in and around Yellowstone National Park, as well as restore bison to other extensive public lands such as the Charles M. Russell NWR, Missouri Breaks NM, and adjacent BLM lands, and then allow natural evolutionary processes to operate with a minimum of human inference.
Yellowstone’s proposed bison management plan suggests it will operate the Park as a bison “ranch” to produce living fodder for tribal gunners on the borders of the Park. This should be seen for what it is–yet another domestication of the Park’s bison herds. Yellowstone bison don’t belong to tribal members, and suggesting Yellowstone’s bison should be managed to appease tribal interests is not in the public interest.
Removing livestock from public lands in these areas with the Voluntary Grazing Permit Retirement program would eliminate the brucellosis threat and thus the excuse that bison must be bottled up in Yellowstone National Park.
Unless we change our attitude and the ways in which we “manage” of bison herds across the West, we are just creating “hatchery bison.”
James Bailey’s book American Plains Bison: Rewilding an Icon provides a terrific overview of the issue of restoring wildness in bison.
You help this dream of wild bison by joining the Montana Wild Bison Restoration Council.