That same land was once grazed by massive herds of buffalo. The native species need large animals grazing to stay healthy. Sure, there's overgrazing in places,

That same land was once grazed by massive herds of buffalo. The native species need large animals grazing to stay healthy. Sure, there's overgrazing in places, but that's a matter of degree. The fact remains that cattle grazing is a necessary step to replace what was lost, if preservation of what remains of native species is desired.