Dry Tortugas National Park (DTNP)

Plant assemblages are mapped in following vegetation classes as woodlands (3), shrublands (8), scrub (5), dune (20), and sparse (3). The vegetation communities on these islands differ in distribution and commonality. Dune associative communities are the main classes that provide significant cover on four of the seven islands. Complete plant species lists and land cover can be found at http://science.nature.nps.gov/im/units/sfcn/inventories/DryTortugasVegMap/Project_Report/drtorpt.pdf

Coral Reefs: The coral reef formations of DTNP include bank reefs, high relief and low relief spur and groove, patch reefs, pinnacles, and other morphologies, which taken together provide an ecological suite of highly complex and productive habitats for fish and invertebrates. Various reefs within DTNP contain high densities of live coral cover and massive star coral heads (Montastrea spp.) that are unique to the Dry Tortugas region. Other common coral species include starlet coral (Siderastrea spp.), brain coral (Copophylia natans, Diploria spp.) fire coral (Millepora alcicornis), finger coral (Porites spp.), and lettuce coral (Agaricia agaracites). Additional species occurring in DTNP are listed in the Appendix (Annex II species list to be added).

Seagrass and Algal Communities: Shallow seagrass and algal communities are important components of DTNP and the wider coral reef ecosystem of the Tortugas. Thallasia testudinum and Syringodium filiforme typically abound in shallower waters <10 m (33 ft). Algal communities in the Dry Tortugas tend to be ephemeral and occur on a variety of bottom types. Conspicuous genera include Laurencia, Dictyota, Sargassum, Cladophora, and Padina. Seagrass beds provide habitat and food for important coral reef fishery species, threatened and endangered species, and many other organisms.

Sea Turtles: The shores of the DTNP islands are important nesting habitat and the coral reefs and seagrass beds forage areas for sea turtles. Loggerhead (Caretta caretta) and green sea turtles (Chelonia mydas) are the most common species known to nest and forage in DTNP. Hawksbill sea turtles (Eretmochelys imbricata) are less common. Sightings of Leatherback sea turtle (Dermochelys coriacea) are very rare, with three nests observed in 2004. (Kemp’s ridley (Lepidochelys kempii) sea turtles are seldom observed in the Tortugas region.) All species are protected under Florida statutes and the United States Endangered Species Act (ESA), and have had their conservation status elevated by inclusion on the International Union for Conservation of Nature (IUCN) Red List of Species (www.iucnredlist.org).

The DTNP islands provide critical nesting habitats for five rare seabird species: the Sooty Tern (Sterna fuscata), Brown Noddy (Anous stolidus), Masked Booby (Sula dactylatra), Magnificent Frigatebird (Fregata magnificens), and Roseate Tern (Sterna dougallii). DTNP contains the only known rookeries for Brown Noddies, Magnificent Frigate Birds, and Masked Boobies in the continental U.S. Sooty Tern sightings at DRTO have been recorded since 1903 and over 500,000 individuals have been banded there since the early 1950s. The Brown Pelican (Pelecanus occidentalis) and Least Tern (Sternula antillarum) also nest in DTNP. The National Audubon Society lists DTNP as one of the Important Birding Areas in Florida.