Bison are bringing biodiversity back to Kansas prairie land
American bison were once so numerous that in 1889 the superintendent of the National Zoo wrote that trying to count them would be like tallying “the number of leaves in a forest.” It’s much of the reason why the exact ecological impact of North America’s largest land mammals was never measured, before colonizers hunted them to near-extinction in the 19th century. But current efforts to restore them to their historic range have affirmed what conservationists and Native Americans have been saying for decades: Bison are critical to the prairie’s health.
New research on the long-term benefits of reintroducing bison shows that their presence makes the land more biodiverse and resilient to drought. A paper published this week in the journal PNAS measures the ripple effects of the giant grazers on the tallgrass prairie ecosystem that used to stretch from modern-day Texas to Minnesota and cover 170 million acres of North America. Today, only about 4 percent of the old-growth prairie remains, mostly in the Flint Hill region of Kansas where the study took place. The data, which spans multiple decades following the bison’s return, is unequivocal: The herbivores more than doubled the number of native species in tallgrass habitats.
[Related: Wolves and beavers can have magical ecosystem effects—if they have space to thrive]
“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 stu
