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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).
The goal of our lab is to create a high-spatial resolution map of coastal forested wetlands at global scale. If we know precisely where these ecologically critical but fragile forests are located, we can manage freshwater flows to counteract saltwater introgression due to rising sea levels, and we can assist in their migration inland, preserving their critical function in protecting coastlines and sequestering carbon.
Across the continent, a number of first nations are in the process of reintroducing bison to the grasslands in which they were once the primary grazer and an ecologically vital species. Initial experiences and evolutionary considerations suggest that this may be ecologically beneficial in terms of grassland biodiversity, carbon cycle, and resilience to climate change. However, these questions have not yet been studied at scale. In this lab, we will leverage remote sensing to scale up from ground measurements, establishing the large-scale patterns of bison impact.
Beaver dams are known to result in greener, more drought-resilient waterways in semi-arid environments. We are using computer vision to spot dams in satellite imagery, generating a large dataset that we can use to train models that will tell us what the ecological effects of a dam will be at any point on a waterway. The goal is to create a tool to guide efficient restoration through the introduction of small dams.
Markets in voluntary carbon credits are increasingly providing a flow of capital for regenerating ecosystems. The problem is, thriving and resilient ecosystems are not just carbon. We need to find ways to structure credits to incentivize the diverse and functional ecosystems we want, not merely high-concentrations of carbon. We will design the technological tools to support a market in bundled ecological credits.
We are building an accurate and global model for predicting potential rates of reforestation and resulting carbon sequestration. Such a model could have a transformational impact on global reforestation efforts by opening new streams of financing in the form of carbon credit futures.
Leveraging The Earthshot Institute’s broad scientific and technical expertise, the Impact and Risk Lab helps investors and governments who earnestly want to forecast, measure, and address the socio-ecological risks to and/or impacts from their work. For a given system, we build simple process-based models to identify key socio-ecological risks and outcomes. We then draw on big data to improve and train our models, generating quantitative predictions and developing measurement systems for verification.