What it takes to save species, locally and globally

The banks of the Potomac River upstream from Washington, D.C., are often mounded with drifts of tiny shells bleached white by the sun. That invertebrate abundance startles me every time I walk the riverbank, a clue to an invisible city of bivalves under the water.

In this issue, freelance writer Stephen Ornes takes us to Appalachia, where he chronicles scientists’ dogged work to restore an endangered species of mussel, the golden riffleshell.