Today, Ron, an experienced sea captain, and the owner of our hotel, took us on his speedboat to the U.S. Virgin Island of Saint John. St. John is unique in the Caribbean in consisting mainly of national park. Made possible by land donated by Laurance Rockefeller, Virgin Islands National Park covers most of St. John, and has allowed the island to maintain more of its natural character and native biodiversity than any other Caribbean island. Unlike the largely unsuccessful laissez-faire approach to conservation that characterizes St. Thomas and St. Croix, the National Park Service provides strong federal enforcement of national biodiversity law on St. John. For example, where St. Thomas hosts hillsides dotted with structures and cleared vegetation, the only structures visible on the North side of St. John, aside from a few privately-owned enclaves yet to be acquired by the National Park, are abandoned colonial sugar mills and the ecotourism tents of Maho Bay. The habitats on St. John vary from mature seasonally-moist rainforest to dry sclerophyll forest, surrounded by an unspoiled shoreline of rocky cliffs and gorgeous white sand beaches, with spectacular coral reefs just offshore.
We moored the boat at Leinster Bay, and snorkeled around Waterlemon Cay. The snorkeling here differed markedly from our previous snorkling sites South of St. Thomas. Here, the fish tended to be much bigger and more plentiful, and we were able more easily to identify more species. In addition, we saw many large fish hiding in crevices in the coral. Much of the coral surrounding Waterlemon Cay was soft and flexible, allowing it to bend and ‘wave’ in the strong water currents and larger waves. We observed more endangered Staghorn Coral (Acropora cervicornis) and Elkhorn Coral (Acropora palmata), though not in the same abundance as at Flat Key. One more fascinating characteristic of Waterlemon Cay was the abundance of tiny translucent Sea Walnuts (Mnemiopsis leidy), which, fortunately, tend not to sting.
After snorkeling, we returned to our al fresco classroom, where we discussed our favorite creatures (especially legal issues involved in their conservation), and then calculated the species richness, evenness, and diversity of the three St. Thomas locations (Botany Bay, Crown Mountain, and Magen's Bay) at which we carried out leaf surveys. The largest species richness and biodiversity was at Crown Mountain (the highest point in St. Thomas), followed by Magen's Bay (halfway down the mountain), and then Botany Bay (near the beach). Crown Mountain is a moist rainforest area, whereas Magen's Bay and Botany Bay (in that order) are generally drier. Additionally, results revealed that Botany Bay had less species richness and biodiversity. Again, this was not very surprising because the area is near water and very sandy. In terms of species richness, diversity, and evenness, the Magen's Bay area is intermediate to the other two sites in richness, evenness, and diversity. Our calculations confirmed our expectation that the Virgin Islands host prodigious quantities of biodiversity, but that the local patterns of biodiversity vary immensely.
More biolaw at LEXVIVO.