Loons, mergansers, cormorants and other waterfowl are dying by the thousands in the Great Lakes due to an invasion of non-native species that are threatening to turn the lakes' ecosystem upside down. At Sleeping Bear Sand Dunes National Lakeshore even piping plovers, a threatened species, are dying.

There are parks across the national park system that have decidedly watery settings: Voyagers National Park, Isle Royale National Park, Channel Islands National Park, Acadia National Park, Biscayne National Park and Dry Tortugas National Park, just to name some of the most obvious. And then there are the national lakeshores.