Amid concerns over the endangerment of species, spaces, and cowboy culture itself, the American Prairie Reserve project could succeed in protecting the contiguous United State’s largest nature reserve. All it will take is $500 million and a passion for progress, each victory measured in blades of wild grass. By Clare Menzel. In the broad expanse of north-central Montana, a prairie dog peeps from its burrow. With shiny black eyes darting, it sniffs.