Recent research on tallgrass prairie in Konza Prairie Biological Station demonstrated that reintroduction of bison, in place of conventional grazing by cattle, resulted in long-running and resilient increases in biodiversity.1,2 Relatedly, research combining remote sensing with field observations in Yellowstone National Park has shown that bison can "engineer the green wave."3 That is, their grazing changes the timing and speed of the spring greening across prairies. Bison grazing caused grasslands to green up faster, more intensely, and for longer duration.
Cattle graze differently from bison4, and therefore they may have different effects on the dynamics of the green wave, as well as soil attributes and biodiversity. On evolutionary grounds, it is reasonable to hypothesize that native plant communities will exhibit greater resilience and total sequestration of carbon under grazing by bison, with which they coevolved, than under grazing by cattle, which are non-native. However, important questions about the ecological benefits of bison versus cattle in various grassland ecosystems remain unresolved.5,6,7 This is a consequential gap: Without rigorous and conclusive science, land stewards interested in implementing this promising regenerative strategy cannot capture or leverage the value of the ecological benefits their stewardship fosters.
Bison Lab has new work unfolding in two different areas. In the Wind River Range, we are working closely with the Eastern Shoshone Buffalo Program to design and develop experimental plots that will be used for two different but interrelated purposes. First, they will be used to assess the ecological effects of rewilded bison on ecological variables such as soil carbon, biodiversity, and water retention. Second, they will serve as one component in the Buffalo Program’s important educational offerings, covering the vital cultural role of the species, opportunities for tribal food security, as well as collection of ecological data and how it may open future opportunities for expansion of the rewilding program.
In Oklahoma, in partnership with the Cheyenne-Arapaho tribes, we are moving forward with USDA-funded work to measure the effects of bison on grassland ecology. While there is suggestive evidence in the scientific literature for potential climate-related benefits of certain practices in bison management, this field of research is nascent. In this project, we will be working with the tribes, as well as our collaborators at Mad Agriculture, to implement regenerative bison grazing practices on thousands of acres of tribal land. In the process, we will be rigorously measuring the climate-related effects of this transition in land use and management. More specifically, we will make direct measurements of carbon dioxide and methane emissions using eddy covariance flux towers, while also conducting intensive soil sampling and measurement of changes in soil biogeochemistry over a period of five years.
It is very clear that in certain cases the reintroduction of bison herds has played a pivotal role in regeneration not only of prairies but also of peoples.8 Further investigation of the relationship between bison and rates of carbon sequestration, resilience of prairie to climate change, and recovery of biodiversity could catalyze widespread transition to an ecologically and culturally beneficial choice to reintroduce bison to an increasing portion of their former range.
1.Ratajczak, Z. et al. Reintroducing bison results in long-running and resilient increases in grassland diversity. Proc. Natl. Acad. Sci. 119, e2210433119 (2022).
2. Harms, K. Bison outperform cattle at restoring their home on the range. Proc. Natl. Acad. Sci. U. S. A. 119, (2022).
3. Geremia, C. et al. Migrating bison engineer the green wave. Proc. Natl. Acad. Sci. 116, 25707–25713 (2019).
4. Kohl, M. T., Krausman, P. R., Kunkel, K. & Williams, D. M. Bison Versus Cattle: Are They Ecologically Synonymous? Rangel. Ecol. Manag. 66, 721–731 (2013).
5. McMillan, N. A., Kunkel, K. E., Hagan, D. L. & Jachowski, D. S. Plant community responses to bison reintroduction on the Northern Great Plains, United States: a test of the keystone species concept. Restor. Ecol. 27, 379–388 (2019).
6. Painter, L. E. & Ripple, W. J. Effects of bison on willow and cottonwood in northern Yellowstone National Park. For. Ecol. Manag. 264, 150–158 (2012).
7. Blackburn, R. C., Barber, N. A. & Jones, H. P. Reintroduced bison diet changes throughout the season in restored prairie. Restor. Ecol. 29, e13161 (2021).
8. Haggerty, J., Rink, E., McAnally, R. & Bird, E. Restoration and the Affective Ecologies of Healing: Buffalo and the Fort Peck Tribes. Conserv. Soc. 16, 21 (2018).