Bring Back the Beavers! Guest: Derek Gow, author of “Bringing Back the Beaver: The Story of One Man’s Quest to Rewild Britain’s Waterways” Derek Gow leads a passionate quest to bring back beavers to Britain's waterways. Historically, they've been considered a pest in Britain, but, in reality, they revitalize water systems. The story of their demise involves the hunting preferences of the landed class, but there's hope for their future as people begin to realize how valuable these busy builders are.  How Carp Conquered America’s Rivers Guest: Andrew Reeves, author of “Overrun: Dispatches from the Asian Carp Crisis”  Carp are one of the world’s most successful river-dwellers. They came to dominate America’s river systems from a series of environmental miscalculations. At the same time, they've become threatened in their native waters. How to restore the balance?