Some states hope to move climate-threatened species, but others say no way

North Carolina might need to move a snail. A tiny mollusk known as the magnificent ramshorn has long made its home in the state's freshwater coastal ponds. But sea level rise and storm surges are making those ponds saltier, and the snail can't tolerate salt. The coastal plain that was once the species' habitat has no snails left—the only surviving members are bred in captivity.