The Last Continuous Grasslands on Earth

WLFW-research highlights largest intact grasslands on earth, including the Central Wyoming Basin and the Nebraska Sandhills.

Dismissed by many as flyover country, grasslands are the most threatened and least protected biome in the world. Numerous studies have focused on documenting declines in grassland ecosystems, but until now, no study has measured where the last continuous grasslands remain on our planet. Spoiler alert, new findings emphasize the role of U.S. Great Plains grasslands and western sagebrush steppe to global conservation.

Newly released research by Rheinhardt Scholtz and Dirac Twidwell, both with the University of Nebraska, detailed and ranked the world’s most continuous and intact grassland ecosystems remaining. The research was supported by the Nebraska Game and Parks Commission and the USDA Wildlife Conservation Effects Assessment Program.

Researchers first analyzed satellite vegetation data from the European Space Agency’s Copernicus program and then used World Wildlife Fund and International Union for Conservation of Nature classifications to measure the degree of intactness remaining for the world’s grassland ecoregions. Grasslands were split between temperate-tropical and desert environments.

Scholtz and Twidwell found few regional grassland ecosystems remain relatively intact, and they discuss the importance of seven remaining grassland regions in the world to large scale conservation. These seven grasslands have persisted over the last several decades in the face of large-scale threats, including land conversion, expansion of woody species and plant invasions.

Two of those regions are found in the United States. The Sandhills of Nebraska ranked as the most intact grassland remaining of the world’s temperate and tropical grasslands at 80 percent intact, and second in overall rankings only to the Altai steppe in Kazakhstan and China. The sagebrush steppe in Wyoming’s Central Basin ranked as the third-most intact arid grassland-shrub steppes and the fourth largest overall at 71 percent intact.

Both ecoregions are critically important targets for conservation work. The Sandhills provide habitat for species like the greater prairie-chicken and serve as a key stopover for the mass migration of avian species along North America’s Central Flyway. Wyoming’s Central Basin hosts the largest population of both pronghorn and sage grouse and provides habitat for some of the world’s longest grassland-dependent ungulate migrations.

The study also demonstrated how the most intact grasslands remaining in the world share common environmental and cultural benefits, which are unique to these systems. In many parts of the globe, sustaining Aboriginal communities and nomadic herders is essential for keeping these grasslands intact globally. Here at home in the U.S. that means supporting sustainable grazing by livestock on working rangelands.

Grasslands across the United States provide healthy air, clean water, and recreational and cultural benefits. Grasslands produce food and fiber, host a dizzying array of wildlife, and filter and store abundant water supplies above and below ground. Underneath grasslands, an upside-down forest of roots and healthy soil play a critical role in capturing and storing carbon. Globally, rangelands contain 12 percent of terrestrial carbon stocks, with 87 percent locked away deep in the soil.

Large and intact landscapes are better able to withstand ecological change, provide more and better wildlife habitat, and are more capable of buffering the effects of global climate change. Additionally, conserving large, intact grasslands is more cost-effective and efficient than restoring them once they become degraded.

The global scarcity of large, intact grasslands is an urgent call to action for the conservation community, and the response should be similar to international attention and efforts related to old growth forests, coral reefs, and rainforests.

In the United States, the U.S. Department of Agriculture is part of this effort, working through the Natural Resources Conservation Service (NRCS) Working Lands For Wildlife (WLFW) effort to protect these core areas from threats, including woodland expansion, land use conversion, exotic annual grass invasion, and riparian and wet meadow degradation. By marshaling the power of the Farm Bill, WLFW is committed to conserving more than 10 million acres across America’s iconic Great Plains and sagebrush country – including both Nebraska’s Sandhills and Wyoming’s Central Basin – through the science-based Frameworks for Conservation Action.

All of us need to protect these grasslands. Working together, we can help keep the last remaining continuous grasslands productive, intact, and resilient

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The last continuous grasslands on Earth: Identification and conservation importance

Abstract: This analysis revealed three findings of critical conservation importance. First, only a few large, intact grasslands remain. Second, every continent with a grassland ecoregion considered in this study contains at least one relatively intact grassland ecoregion. Third, the largest remaining continuous grasslands identified in this analysis have persisted despite last centuries’ anthropogenic pressures and have the best chance to withstand 21st-century pressures of global change.

We discuss how these regions are of critical conservation importance to global grassland conservation efforts under anthropogenically driven global change. They provide essential ecosystem services, play an important role in mitigating the effects of climate change, serve as critical repositories for grassland biodiversity, are foundational for continental migration pathways, hold unique cultural heritage, and people’s livelihoods depend upon their persistence.

Citation: Scholtz, R., & Twidwell, D. (2022). The last continuous grasslands on Earth: Identification and conservation importance. Conservation Science and Practice, e626.

Permanent URL: https://doi.org/10.1111/csp2.626

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