Bison

By Kendall Buckingham, Rochester Pines Field Crew Member / AmeriCorps Member

For the Rochester pines, one of our main ongoing projects has been assisting with several goat grazing sites. These goats are used to defoliate buckthorn, forcing it to use up its stored energy to refoliate. This process stresses the buckthorn, which slows or stops regrowth.  Being a part of this project has left me in awe of the power of these little habitat engineers. They are able to accomplish more in a few weeks than a CCMI crew could accomplish with years of work.

Seeing the effect of the goats on the landscape made me wonder how other herbivores may have shaped the land. Historically bison would have been the main herbivore shaping the landscapes in the so-called bison belt spanning from Canada to Mexico. It is hard to understand the exact effects bison due to their current limited distribution. However, it’s thought that many plants in the bison belt had to adopt flexible growth patterns to tolerate bison grazing patterns. This can be observed in the greater Yellowstone ecosystem; home to the only free roaming bison in the united states. While other herbivores follow the freshly sprouting plants and grasses during spring, bison leave their winter ranges but let the wave of greening vegetation pass by them. They spend their time returning to the same area to intensively graze repeatedly, allowing plants to still grow but remain small. This behavior allows the bison to continually get highly nutritious forage.

It has been thought that cattle can fill the void that is Bisons ecological niche due to their perceived similarities. However, it’s been well documented that not only do bison roam more, but they also use more of the landscape, and eat rougher, less digestible food. A study done by Van Vuren (1979) in the Henrys Mountains located in Utah showed that a herd of introduced bison stayed further from water sources and used steeper terrain and higher elevations than cattle. The study also stated that they rarely stayed in one space longer than three days. In another study, cattle have been shown to be inefficient water users showing a preference for moister forage. Pinchak (1991) and colleagues reported that 77% of the observations of cattle grazing were in the foothill ranges of Wyoming within 366 meters of water. This shows that cattle had a marked preference for floodplain habitat unlike bison, who feed primarily in open grasslands and meadow communities. Grasses, sedges and other grasslike plants make up more than 90% of their diet, with the remaining percentages being forbs and woody plants.

It is my dream to see bison once again roam their historic ranges. This dream however has many challenges, most of all urban sprawl. As land development expandsnatural grasslands are turned into farmland or residential areas. This development disrupts the habitat that bison need to graze, migrate and reproduce. Habitat fragmentation is causing isolated populations, limiting genetic exchange and reducing species health. In order to remedy this, we must establish corridors between habitat patches to increase connectivity, allowing for more sustainable populations. To accomplish this goal, we must safeguard our public lands. Without this resource we cannot continue our great work. Not just for us, but for our future.

Bison Ecology – Yellowstone National Park (U.S. National Park Service)

Bison ecology, ecological influence, behavior, and decline. – The Wildlife News

Van Vuren, D. 1979. Ecology and behavior of bison in the Henry Mountains,

Pinchak, W.E., M.A. Smith, R.H.Hart, and J.W. Waggoner. 1991.

“Bison herd, Lamar Valley” by YellowstoneNPS is marked with Public Domain Mark 1.0. To view the terms, visit https://creativecommons.org/publicdomain/mark/1.0/?ref=openverse.

“Bison” by a.dombrowski is licensed under CC BY-SA 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/2.0/?ref=openverse.