Bison, the great heroes of the Great Plains

Plants, from trees to seagrass, play a recognizable role in combatting climate change. But wildlife too are heroes in the climate fight. Large herbivores, like the plains bison in North America’s grasslands, keep habitats and ecosystems intact and vibrant at a time when nature is facing devastating losses.

Across the Great Plains, as grasslands are plowed and converted to make space for row crop agriculture, vast amounts of carbon stored within the soil are released. Each year, as more and more grasslands are converted, millions of tons of carbon escape into the atmosphere, worsening the climate crisis. Alternatively, native grazers on the landscape, like bison, keep grasslands intact and promote a wide array of biodiversity.

Restoring top predators—such as tigers— for the benefits they provide in maintaining ecosystem balance is a major focus of biodiversity restoration, while the equally important role of herbivores and native grazers has been highlighted less often. As a keystone species, bison play a vital role in maintaining a healthy ecosystem capable of storing large amounts of carbon.

Superpower: Grassland invigorators

Bison, or buffalo as they are commonly referred to, are the largest land mammal in North America. They were nearly driven to extinction by settler expansion and the U.S. government in an attempt to subdue Indigenous peoples. The ongoing restoration and recovery of bison is an inspiring conservation success story. Their resurgence as a wildlife species, primarily on Indigenous and federal lands, has helped local flora and fauna along the prairie.

Bison behavior creates unique habitats for medicinal plants and specialized insects. By grazing and wallowing, bison break the soil’s surface to allow rainfall to be absorbed into the grassland roots. As bison graze, their vigorous munching spurs the growth of new, nutritious plant shoots, sending roots deeper into the soil, which promotes carbon sequestration. This all leads to a landscape that not only supports rich biodiversity but also has the potential for carbon storage capabilities.

Moving across the prairie, bison supply nutrients to the soil through their dung and urine (which are rich in nitrogen, a vital component for plant growth) and disperse seeds that continue to populate the ecosystem. Bison are enthusiastic grazers, and their movements across the grasslands have been referred to as a “green wave,” because it stimulates incredible plant growth across the landscape. This “wave” of new vegetation then feeds other animals. It’s a phenomenon so intense that it can be seen from space.

By helping grasslands flourish, these herbivores indirectly increase a grassland’s ability to store carbon. When bison are restored to the landscape, it has been shown that plant species diversity increases, more pollinators are present, and grassland bird numbers increase (conversely, all of these experienced declines with the decimation of the bison). When ecosystems are more diverse, they are also more resilient to the effects of climate change and better able to sequester and store carbon.

Superpower: Resilient partners

The global threat of climate change impacts all of the planet’s ecosystems, including the Great Plains. Grasslands have suffered extreme drought and increased flooding in recent years.

Fortunately, because bison have lived for millions of years in this landscape, they have evolved with the ecosystem and their natural behaviors work in concert with the rest of the prairie. This means bison are better equipped than domestic livestock to handle extreme changes in weather, from scorching summers to the freezing winters and from periods of drought to record setting snow depths. Given the space to do so, bison will continue to evolve with the grasslands.

Looking to the future: a cultural, ecological, and climate icon

Bison are integral to the health of the Great Plains, including its people and wildlife. The incredible effort to bring back bison to North America has been led by Indigenous people, conservation NGOs, and the federal government. This restoration effort has not only been a victory for bison and grassland biodiversity, but also for many Indigenous communities’ cultures and ways of life.

Two centuries ago, bison dominated North America, with tens of millions roaming the Great Plains, from Mexico all the way up to Canada. Some referred to these vast herds as “Rolling Thunder” because of the sound of their hooves pounding the earth. For many Native Nations, bison are a sacred animal, whose bodies and presence nourish people, spiritually and physically. Tragically, settlers slaughtered millions of bison during western expansion. Bison now occupy less than 1% of their historical range.

It has never been more critical to restore more of these herds to the landscape. As nature faces a worsening crisis, bison increase biodiversity and help grasslands capture and retain carbon. Their power lies far beyond their nearly two-ton frame in the fight against climate change.