🦬 Bison are bringing biodiversity back to Kansas prairie land

New researchers regarding the long–term benefits of reintroducing the bison have proved what conservationists and Native Americans have been saying for decades: the bison are critical to the prairie's health. The research shows that the presence of the bison helps the land be resilient to drought as well as makes it more biodiverse.

In a paper published recently in the journal PNAS, measured the ripple effects of the bison on the tallgrass prairie ecosystem. Sadly, only 4% of the old-growth prairie remains and the data, spanning multiple decades since the giant grazer’s return, shows loud and clear that the herbivores more than doubled the number of native species in the tallgrass habitats.

“Bison are the type of organism you’d expect to have a large impact,” says Zak Ratajczak, a biologist at Kansas State University and lead author of the study. “They’re very large, travel long distances, and can consume plant species on a scale that changes competition.”

Bison, unlike many other herbivores, specialize in eating big bluestem and other tough grasses. If these grasses are left untouched they grow really fast and tall, shading out other plants needed for biodiversity. For example wildflowers which support pollinators and legumes that fix nitrogen in the soil.

According to Ratajczak: Given enough time the cumulative, cascading impacts [of the bison] are large.

Scientists at the 8,616-acre Konza Prairie Biological Station in Kansas, have since the 1980’s documented changes to plant biodiversity with the reintroduction of the bison herd. In recent years, the number of bison have kept steady with between 275 and 300 individuals.

In order to compare, they also tracked the health of similar areas that were grazed by cattle together with parts that went entirely untouched. According to Popular Science, one thing the results showed was that bison-occupied prairie was better able to cope with weather periods of drought all thanks to greater variety in plant species and newly stimulated growth from grazing.

“It’s heartening to see resilience that it could weather some degree of warming,” says Ratajczak, pointing out that this will be especially important with the predicted increase in intensity and frequency of extreme heat in the near future due to climate change.  

A world that lives in ecological balance and coherence can help a brighter future come sooner.