How are bison able to change a landscape? How is their grazing regime different from cattle? What are some physiological and behavioural differences? How have bison coevolved with native grasslands and their environment as well as other species?
Bison are key in sustaining and enhancing native biodiversity and the health of ecosystems. They create physical disturbances on the landscape crucial in maintaining habitat health. These include: the trails they form through winter to enable ease of travel for many species and minimizing disturbances to the soils and vegetation beneath the snow and ice, the manure they leave behind on the landscape that helps to fertilize the soils and recycle nutrients, while providing food for so many different species, the wallows they create that are important havens from the elements as well as for holding water and loosening soils, and the characteristic patch grazing where patches of longer grass are left for cover and food for a diversity of wildlife, whereas shorter grasses are preferred by the endangered Prairie Dogs so they can easily spot predators. The pugging they create with their hooves helps regenerate grasslands, whereby their sharper edged hooves aerate the soils and allow seeds to grow. Bison play an important role in the life cycle of many species, such as dung beetles, ticks and internal parasites. They are a main food source for predators, such as wolves and grizzlies, and for scavengers, such as crows, and their carcasses have ecological benefits, too.
Bison are a key component in the grassland food web relationship. They help facilitate grazing by deer, cottontails, pronghorn, and prairie dogs. The Sexton beetle buries bison tissue from carcasses and transports phoretic mites that help feed a huge number of birds, reptiles, and amphibians. The presence of bison and their activities in the prairies helps sustain 77 species of grasshoppers, which in turn are hunted by grasshopper mice. In the Yukon bison were introduced in the 70s and squirrels were observed lining their nests with bison fur, increasing their survival rate and populations immensely. Listed species, such as the Horned Lark, have been observed to make nests in the depression created by bison footsteps, and use shed bison fur to line their nests, thus increasing their survivability. The heterogeneity of the landscape created by bison provides for many species’ needs.
Bison share the landscape with many different species, including some 26 species of endemic birds, and some 35 mammal species, many of which are listed under the Species at Risk Act. Bison are an integral part of the ecosystem and benefit all life, from the microscopic spores and microflora and fauna to the largest animal species.
Pronghorn Antelope travel 800 km during their annual migration. There are some residents that stick around all winter and some that are migratory. It is thought that the removal of bison probably increased the migrations of Pronghorn Antelope and hence their mortality rates because the winter trails made by bison that the Pronghorn used were no longer available.
Believe it or not, bison snot is one of the most important components of grassland health because it is the microbes in the dispersed bison snot that drives the entire ecosystem. When bison graze, the nostrils are exposed to the vegetation. They inhale dust, microbes, bacteria, and fungi, which gets hung up in the nasal vestibules. The bison licks its nostrils and swallows the microbes and fungi, which provides a whopping 1/4 of its protein intake and also aids in digestion. Millions of microorganisms are digested this way. The fungi break down the starch, the bacteria break it further down into sugars and provide fibre, the protozoa hunt the bacteria, and the fungi breaks down the cellulose. Protozoa occur by the millions in the rumen. All this gets excreted, and comprises the bison patty ecosystem, which is populated by the fungi, bacteria and protozoa. This concoction in turn feeds the dung beetles, flies, and other insects. These insects lay eggs on the dung, then the larvae hatch and are eaten by birds and other creatures. And the cycle begins again.
Dung beetles are nature’s gardeners. They solely rely on dung. They eat protozoa and bacteria, and fun fact, the “rollers” only roll their brood ball from dung during full moon. Prairie dogs eat the dry dung in early spring. One manure dung patch can support 100 species of insects. It is estimated that 300 billion insects were produced during peak bison populations. Imagine how many animals that must have fed. The decline of the bison naturally led to a decline in bison snot and bison dung, and hence a decline in birds and other species relying on it for food.
In winter, bison created grazing lawn micropatches. These were the first to green up in the spring providing active soil microbes where pocket gophers thrived. The pocket gophers created many underground tunnels, which provided habitat for snakes and up to 29 other species. In one study, prairie rattlesnakes preyed on pocket mice that ate the seeds of plants. The seeds then germinated during snake digestion and spread, which increased vegetation diversity and habitat for other creatures.
Bison hair was also abundant. It is the second warmest fibre in North America, the first being the fur of the Musk Ox. Many species used bison fur for lining their nests. It was also used as an olfactory masking agent for birds against predators. The bison fur was also water repellent. Thus, the survival rate of birds increased. Ground squirrels also used bison fur to line their nests. Bison wallows provided dust bathing for other animals to condition fur and skin and get rid of pesky flies and other pests and parasites. Wetlands created by the wallows were used by the endangered Spadefoot Toads and Great Plain Toads. Eggs were also laid in these wallows. Pronghorn babies used bison bowls to hide from predators and as protection from the strong winds. The endangered Mountain Plover used the crumbled bison patty for nests. The endangered Sage Grouse used the wallows for dancing grounds. Ant hills were established on bison dung. Northern flickers hunted ants and created nesting cavities that northern flying squirrels used for a variety of purposes, including cavities used as their toilet. Hidden in flying squirrel dung are tiny dung beetles that are found no where else.
Once the bison was removed from the ecosystem it resulted in an ecosystem collapse, as all components were affected. The ecological consequences were profound. It is hoped that bringing back the bison will re-establish these significant connections and hence increase biodiversity and ecosystem health.
Since bison no longer have natural predators, e.g., wolves, grizzlies, cougars, on the prairies, how can their numbers be managed? Should these predators be encouraged to repopulate to help rebalance grassland ecology and restore predator-prey relationships for a healthy ecosystem, including other species? It is known that some grizzlies are starting to move back onto the plains. How could this be achieved in the best possible manner?
Predators, such as wolves and grizzly bears do move in naturally, but they are generally not tolerated by landowners and are usually killed and hunted. Introducing large predators to National Parks are usually not supported by adjacent landowners, such as ranchers, but if these predators arrive on their own then they are afforded protection within the boundaries of the Park. However, as soon as these large predators leave the safe haven of the Parks, they are generally shot and killed. This makes it difficult for large predators of bison to establish and evolve a balanced predator-prey relationship and thus, human management of bison is continuously required. Until we learn to coexist and manage our own tolerance and behaviours, it is unlikely that large wild herds without human interference will ever be achieved.
How can ranchers be encouraged to augment or switch to bison ranching from cattle ranching on native prairies? What are some pros and cons? What are some of the benefits and advantages? How can this message be delivered effectively or be promoted? Is there a risk to upsetting social structure of the animals in these controlled scenarios?
Most ranchers think cattle are best and that is what they are used to. They think bison are difficult to handle and manage. You have to learn the behaviour of bison to be able to effectively handle them. Setting up infrastructure for handling and managing bison can be quite complicated and costly at first. However, once established, it becomes very efficient and cheap. When you cage and tag young bison, the mom becomes extremely protective and dangerous. You have to be able to isolate the calves effectively without interference from the mother. Therefore, fall is the best time to tag when the mother leaves the young. Transponders placed in the tail have been known to be effective. Ranchers also view the bison industry a threat to the cattle industry.
Bison are a lot gentler on their environment than cattle and are virtually maintenance free. When bison drink from dugouts they do not muddle the edges like cattle, but vegetation remains along the edges. They drink and walk away from the dugouts, and do not hang around like cattle do, dispersing on a larger more diverse landscape. They do not over-utilize resources. They eat 1/3 less than cattle and retain nutrients 1/3 longer, and they do not drink as often. They can go as long as 6 weeks without water, obtaining their water needs purely from vegetation. It is hypothesized that bison wallowing mixes the rumen contents, which also help to absorb moisture. But until ranchers are convinced that bison could be a more cost-effective, lucrative and natural alternative to the cattle industry, and better for the environment, the battle between bison and cattle will continue.
What is the status of bison in Wood Buffalo National Park? Where are the largest wild self-sustaining populations found in Canada and the US?
The largest self-sustaining wild populations of Plains Bison are found in Yellowstone National Park. The purest populations occur in Pink Mountain National Park in BC where there are more than 1000 Plains Bison, the largest disease free purebred herd in North America. Elk Island National Park has disease-free herds and this is where most of the source bison come from if an area needs to be repopulated.
Do you know the status of the bison reintroduction in Banff National Park? Will it be a success? What are some of the challenges they are facing with that program? What could be done better in the future? What are some opportunities?
The Banff National Park bison reintroduction program received much public support. The program was initiated by the Bison Belong campaign as a citizen-based effort to support the reintroduction of wild Plains Bison back to their natural habitat in Banff National Park. In 2009, the Eleanor Luxton Historical Foundation championed the reintroduction effort, advocating to renew the ecological, cultural and historical values of this iconic species in their native habitat.
The reintroduction was first talked about in the early 80’s by Cliff Whyte, a retired biologist in Banff, who was passionate about bison. He was a key influencer in challenging Parks to pursue the reintroduction program. A Blackfoot elder, Leroy Little Bear, was also instrumental in the program as he saw a rock shaped like a bison in the fall of 2016, which he interpreted as a sign that the reintroduction must occur at that location. In February 2017, the bison reintroduction became a reality.
Within the confines of the release area in Banff National Park, the area has a carrying capacity for about 1000 bison. The program has a 5 year trial basis. The population status for this year has not yet been established. The area of release is designated as a Plains Bison Wildlife Zone. Parks continues to work with surrounding land owners and the Parks management team to monitor the health, behaviour, movement and population of the herd to ensure everything remains on track.
What is your message to wildlife biologists regarding bison? What kind of research is lacking? How can people promote bison reintroductions and conservation?
Get involved, get educated on bison, and take action to advocate for their reintroduction and protection of critical grassland habitats. Learn and teach about coexistence, biodiversity and the web of life. Familiarize yourself with the Parks Management Plan, a key document to help in the reintroduction effort. Have a plan in place and be able to clearly relay the message of the important ecological roles bison play in the environment. Connect with groups that promote bison conservation and education.