In their PBS Terra videos, Michael Werner, Joe Hanson, Rachel Raney and Brandon Arolfo explore the ongoing attempts to save two threatened ecosystems―the American prairie and the ancient forests of the Pacific Northwest. “How Bison Are Saving America’s Lost Prairie” focuses on the Joseph H. Williams Tallgrass Prairie Preserve in northeastern Oklahoma, a 40,000-acre expanse where scientists from The Nature Conservancy are using bison to restore the area’s ecosystem after years of destructive overgrazing by cattle. The herd of more than 2,000 bison now helps foster the ecosystem’s rich…