American Bison (Bison bison) are one of the largest grazers in North America. All of the photographs and video footage are of bison in the Yellowstone National Park. These bison behave much as they did 200 years ago. They graze frequently and nearly constantly as seen in the video. Konza Prairie Biological Station in Kansas is one of the only places to test the effects of bison grazing relative to areas without grazing and grazing by cattle. Their 10 year study suggests that if bison and livestock are managed similarly, they can both have positive effects on plant diversity relative to no grazing. They are an iconic symbol of the American west and remain a part of the American identity.
A highly politicized issue in Montana regards the risk that bison in Yellowstone National Park pose to cattle outside the park. In winter, bison often attempt to roam outside the park while looking for more suitable sites to graze. Livestock producers are concerned about the risk of transmission of Brucellosis (Brucella abortus) from bison to livestock on neighboring ranches. This disease is problematic because it can cause spontaneous abortions in livestock and wildlife--although not considered a direct threat to human health. The disease was introduced to this country with imported livestock and spread to wildlife. Now the disease is nearly eradicated except for some wildlife populations.
The risk of infection is greatest when exposed to tissue/fluid resulting from calving or abortion. So livestock producers are concerned about the risk of transmission when their herds associate with wildlife (bison & elk) or are in pastures that were associated with wildlife. This is a major problem for livestock producers for two main reasons. Obviously, the disease can negatively affect production (reducing calving rates). Export can also be affected because infections in Montana cattle will jeopardize the state's nationally recognized Brucellosis-free status and negatively affect the industry's (7th largest herd in USA) ability to export livestock. A change in the state's Brucellosis free status will negatively affect all livestock producers in the state whether they are in an area that is at risk (near Yellowstone) or not. Losing this status will require costly tests to ensure heathy exports. So a management plan has been established that prevents bison from leaving Yellowstone National Park. Those that do leave are hazed back in, captured, and/or killed.
A recent case of Brucellosis in cattle in Montana (May 2007) actually occurred away from the park in Bridger, MT (~90 km away). However, the cows are suspected of coming from another ranch in Emigrant, MT which is closer to the park and its bison (~33km away). The fatal flaw in attempting to manage Brucellosis by focusing most efforts on the relatively small bison herds in Yellowstone is that elk, which are widespread in Montana (~130,000 in Montana) and the surrounding states, also carry the disease. Elk are thought to have behaviors that are less likely to result in successful transmission relative to bison but winter feeding grounds, that keep them at high densities, increase the probability of contagious spread. Ironically, the feeding grounds are intended to keep elk from competing for forage with livestock. So the debate will continue as to whether the federal government is responsible for controlling bison &/or vaccinating the park's bison herd, whether the state will have split state Brucellosis-free status (near park vs. away), how elk will be managed/vaccinated, or whether the cattle industry will vaccinate its herds (regionally or statewide).
This video represents a collection of sequences shot with a Canon Digital Rebel controlled by a TC-80N3. Photographs were shot at an interval of one every 2 seconds. Although they appear relatively docile, bison injure more people in Yellowstone than any other wildlife, so many of the sequences were shot using a supertelephoto lense (400mm).
