Ecological future of bison in North America: A report from a multi-stakeholder, transboundary meeting

In North America, many wide-ranging mammals have experienced significant declines within the last 200 years: Now, elk are found in only 26% of their historic range and grizzly bear are found in only 47% of theirs (Laliberte and Ripple 2004). This loss has resulted in fewer landscapes rich with large mammals and lower densities of mammals in many of the rest of these landscapes. Nowhere is this more dramatic than is the case with the North American bison, which experienced an ecological loss at a scale unparalleled in our modern history. Only 200 years ago, 30-50 million plains bison (Bison bison bison) roamed the grasslands and shrub steppes from Mexico to central Canada. To the north, wood bison (Bison bison athabascae) ranged from boreal forests to the Arctic plain. In herds that numbered up to 10,000 animals, bison were an ecological keystone species on the Great Plains and montane grasslands. Their migrations, grazing patterns, and behavior shaped the physical environment and they had myriad ecological interactions with other native species. Bison were also integrally linked with the spiritual and economic lives of original American cultures, and embodied the frontier for many Americans. Due to massive overhunting and land-use change, bison were pushed to the brink of extinction. By the 1870s bison were decimated by the onset of the railroad and the robe trade. By 1889 only about 1,091 bison were left. Today, the bison remains a unique icon of North American culture and natural history. The numerical restoration of bison, which now number approximately 450,000, could be considered a conservation success story. However, the bison’s important ecological roles in the landscape have not been restored, as over 95% of these animals are being raised in confined circumstances for meat. In fact, today bison exist in vastly differing management circumstances, herd dynamics, states of genetic integrity, and ecological settings than in the past. Bison are absent from most of their former range, their grazing does not influence the grassland-fire or nutrient-cycling regimes, and they rarely create habitat or provide food for other native species. (abstract continued below in 'General notes')