[Un]Natural Selection Ep. 6: Damned If We Do, Damned If We Don’t

Over time, people have caused extensive damage to rivers by scouring their banks with logs, channelizing them through towns and cutting them up with dams. In the last 50 years, scientists have discovered removing dams can vastly improve conditions in rivers. But not all dams can come down. Sometimes they are our greatest protection against invasive species.