What is Bio-Diversity? Bio-diversity refers to all of the different kinds of life forms found in an area. When the US Fish and Wildlife service says that the Virgin Islands is in the most bio-diverse region of the USA, it means that the islands have more types of life that any where else in the country! One of the best places on St. Thomas to quietly enjoy the incedibly diverse qualities of nature is at the relatively secluded wetlands of Mandahl Bay, St. Thomas, Virgin Islands.