Cale Benefield, Unsplash
Bison are vital to maintaining the health of the Great Plains, but fewer than 10% of current bison populations are managed for conservation or considered wild. This limited recovery hinders their ability to fulfill their historical ecological roles. Restoration of this species is a key priority for biodiversity conservation in North America.
Bison are a keystone species whose presence and unique behaviors significantly shape the ecosystem. With them, the biodiversity of our prairies could recover, bringing back the abundance of hundreds of species that depend on bison’s unique behaviors, such as grazing, wallowing, and trampling. These activities create a mosaic of habitats, with varying grass heights that support a range of wildlife, from birds like the Thick-billed Longspur to small mammals and insects.
Bison contribute to carbon sequestration by promoting grassland health. Healthy prairies, maintained by bison grazing and their influence on plant diversity, store significant amounts of carbon in their soils. Grasslands serve as carbon sinks, helping mitigate climate change by storing more carbon than degraded landscapes. Bison’s movement across large areas also helps prevent overgrowth of invasive species and maintains the balance of plant diversity, ensuring that the prairie ecosystem continues to thrive.
Restoring American bison in prairie grasslands can sequester 595 MtCO2 per year. This is 1.08 x the total fossil fuel CO2 emissions by Canada in 2022 (548 MtCO2/y) or 12% of the USA (5,057 MtCO2/y) ¹
Edwin Hooper, Unsplash
How do American bison help store carbon?
- Grazing and Vegetation: By grazing in large herds, bison create patches of low and tall grasses, providing habitats for species with varying needs. Low vegetation areas are ideal for birds like the Thick-billed Longspur, while denser vegetation supports species like the Sprague’s Pipit and Baird’s Sparrow.
- Wallowing: Bison’s wallowing behavior—rolling in dust or mud—creates depressions that collect water, forming mini-wetlands. These shallow pools are vital to plant growth and water retention, enriching the prairie ecosystem.
- Nutrient Cycling: As bison decompose after death, their bodies provide valuable nutrients, enriching the soil with nitrogen and phosphorus, essential for plant growth.
Current situation – what we need to do
Bison are currently classified as livestock in many regions, which restricts their ability to roam and behave in the way they naturally would in the wild. Restoring wild bison populations is a key step in preserving the biodiversity and ecological integrity of the prairies, while working with local stakeholders and neighboring cattle ranches to promote coexistence. By supporting such efforts, we can help ensure that bison once again roam freely, as they did for millennia.
To learn more, check out American Prairie: https://americanprairie.org/bison-restoration/
(1) Note: These species data are from Table 1 and the Supplementary Appendix 1 of Schmitz, O.J., Sylvén, M., Atwood, T.B. et al. Trophic rewilding can expand natural climate solutions.
Nat. Clim. Chang. 13, 324–333 (2023). https://doi.org/10.1038/s41558-023-01631-6
Next steps
- Return to the main Climate Heroes page.
- Read all the original Climate Hero case studies in ‘Animating the Carbon Cycle: Supercharging Ecosystem Carbon Sinks to Meet the 1.5°C Climate Target’. Download the pdf here.
- Curious to learn more? Watch the video from the UN Climate Change Side Events at COP28: Bringing elephants into the room – why UNFCCC needs to put animals on the table.