Yellowstone’s Bison Revival Shows the Power and Complexity of Rewilding

In the 1870s, one observer saw a bison herd along the Arkansas River estimated at 3 million, blanketing nearly 1,000 square kilometers. Such massive movements of these animals through the heart of North America rivaled the vast migrations that swarm across Africa’s Serengeti today.

But mass slaughter sanctioned by the U.S. government reduced these vast herds to just a handful of creatures confined to private ranches and places like Yellowstone National Park.

Now, a resurgence of bison inside that park is giving scientists insights into the ecological power of these massive creatures. There, a herd of some 5,000 animals migrating back and forth within the confines of the park are transforming their grazing grounds, altering nutrient flows and microbial communities in ways that enhance plant productivity and nutritional value, according to a new paper in Science.