Here is a link from The American Prairie Foundation about its sprawling 3.5 million acre reserve in Montana. It’s a video that shows noted American biologist E. O. Wilson describing the need for creating large wildlife reserves, such as the American Prairie Reserve.
There are certain habitats on earth, and the Great Plains is certainly one of them, where a small parcel of a few acres is not sufficient as a working ecosystem. Thousands, or even millions of acres are needed to allow for enough resources for all of the historical wildlife to exist.
In addition to the content, there are also beautiful photographed scenes of the reserve in Montana to serve as a reminder of what once was. Enjoy.