But this glittering tale would end in tragedy. When Europeans first reached North America, prairie land covered more than a quarter of the continental United States. A highly complex system of interdependent plants and animals, the prairie once supported some 60 million bison. Prairie plants are specially adapted to fire. Their deep root systems help them survive and are even stimulated by a blaze.
Bison like to graze on the young tender grass shoots that grow in the aftermath of a burn.
The flowering plants the bison don't eat grow back in force since they have less competition from the grasses. These plants then attract an array of birds, insects and small mammals. Eventually the grasses grow back, they burn again, and the whole process starts over. It's too late to restore the Great Plains to anything approaching their former glory. But the captive-born animals weren't having much luck making it on their own.