Don Matesz wrote an excellent post on his Primal Wisdom blog about an organization that has managed to turn desert land in Zimbabwe back into lush grasslands. How? By returning masses of livestock to the ecosystem.
Read the post if you get a chance, and look at the before-and-after pictures. This is exactly what Lierre Keith pointed out in her wonderful book The Vegetarian Myth: livestock aren’t ruining the earth. Mono-crop farming is ruining the earth. Livestock and grasslands need each other.