Where the buffalo roamed

There are two ways in which a species may become extinct — when the last individual dies, or by hybridization. North American bison, the largest and most iconic land mammal in the western hemisphere, are threatened by both.

Thirty million bison once roamed the continent, from Texas to the Canadian Arctic. By 1890, the species was on the brink of extinction with fewer than 350 animals left in existence. Both plains and wood bison were once keystone species — species upon which an ecosystem and its inhabitants depend.

Bison have a special role in the history, culture and economy of North America and have been revered by indigenous peoples for generations as both a critical resource and for spiritual and cultural connections. The decline of the bison has not been due to natural causes; it is a result of over-harvesting by humans. The decline of the bison has affected every aspect of the central plains and boreal regions, and is paralleled by the decline of First Nations people.

Reduction of the bison population by greater than 99 per cent has resulted in a crisis of genetic diversity. With fewer traits available in the gene pool, the resilience and long-term viability of the remnant population is compromised and may fail to adapt to climate change, disease or a shift in available resources. Population bottlenecks that span several generations — as has been the fate of bison — render a species particularly vulnerable to catastrophic loss.

Recent growth of commercial bison farming accounts for the vast majority of the bison population in North America today, and these herds represent tremendous potential as a genetic resource for conservation efforts. However, the creation of cattle-bison hybrids over a century ago resulted in cattle gene mixing that persists today. The true extent of hybridization remains unknown because genomic tools that distinguish hybrids haven’t been developed yet. Until these tools are available, this potential remains untapped.

In Canada, only 1,500 plains bison exist in five non-hybrid conservation herds, all of which descended from only 50 individuals rescued during the early 1900s. Wood bison are indigenous to Canada, but the largest population in the world — located in Wood Buffalo National Park — is afflicted by cattle diseases (brucellosis and tuberculosis) introduced during the early 1900s. Today, recovery of the bison species is hampered by the following issues:

• the existence of small isolated populations
• endemic diseases transmissible to livestock and humans
• hybridization

Social, political and scientific commitments are needed to address these problems.

The development of a bison genome biobank is offered as a first step in a new, exciting phase of bison recovery. Successful establishment and use of this biobank provides a solution to a longstanding and complex problem.

• The biobank will enable a more effective wildlife management strategy, thereby protecting both the agricultural livestock sector as well as human health and safety.
• It will help mitigate disease transmission and facilitate the re-establishment of bison throughout their vast former range, restoring the ecological balance of the grassland and boreal forest regions.
• Commercially, bison producers will benefit from having access to new genetics, improved breeding management, and expanded national and international markets.
• Revitalizing the bison will have symbolic and material impact for First Nations communities and tourism in and around Canada’s National Parks. Working together with Indigenous people, all levels of government, industry, scientists, policy makers, and conservation groups, the bison biobank will be a key tool in maintaining the optimal numbers of healthy, genetically-valuable animals in the wild for future generations.