Conservation gets complicated when a native U.S. species is appreciated in one part of the country, but despised in another. Consider, if you will, the American bullfrog. “In the Eastern U.S ...

The Gila chub once benefited from the engineering feats of beavers living in the upper Gila River basin, whose dams created deep, slow-moving pools the chub loved. So in the late 1800s, when beavers ...