Coral is a foundation species – one that creates the habitats that support biodiversity and provides essential shoreline protection. The waters of Dry Tortugas National Park, which lies about 60 miles to the west of Key West, Florida, are home to some 30 species of coral. One type –- Elkhorn Coral -- rises above the rest, literally and figuratively, for its importance in the region. It also happens to be the most threatened.