Sub-region 6 is comprised of a rich diversity of terrestrial and marine habitats, including tropical hardwood hammocks, globally endangered pine rocklands, fringing mangrove, transitional wetland habitats, seagrass meadows, tidal passes, hard bottom communities, and patch and fringing reefs.

The geographic setting of the Sub-region includes the southern portions of Florida Bay and Biscayne Bay, the Florida Keys from Soldier Key to the Dry Tortugas, and the Florida reef tract. Also included are the nearshore and tidal pass areas between and surrounding the Keys and the Gulf of Mexico shelf area lying just north of the westernmost Keys.

Geologically, the area is characterized by the emergent islands of the Keys which are representative of a Pleistocene reef tract (100,000 years) known as the Key Largo Limestone formation, in the easternmost Keys, and the Miami Oolite formation in the westernmost Keys.

Though only the southern portion of Florida Bay lies within the Sub-region, it is worth noting that this is an expansive area of interconnected shallow water banks and mangrove islands. Recently, extensive seagrass die-offs and the development of algal blooms and areas of high turbidity have threatened the ecological health of Florida Bay (Sub-region 3) and this Sub-region.

The Florida Keys represents a complex mix of tropical flora and temperate fauna. Many endemic species are found in the Keys. Because of the small island setting, in addition to the encroaching impacts of humans, approximately 71 plant and over 20 animal species are considered Threatened or Endangered.

Shallow water patch reef complexes and the reef tract make the Sub-region unique in the continental Untied States. Characteristic of coral reef environments, they exhibit high biodiversity of both invertebrate and fish species. The overall health and stability of these areas is dependent on clear, oligotrophic waters. Currently, the flow of degraded waters from Florida Bay is having a defined impact on some of the reef tract areas, particularly adjacent to major tidal passes between the Keys. Additional impacts are result from less manageable impacts that seem to be occurring on both a Caribbean and global scale. Researchers have noted increasing incidents of coral disease and diminishing coral cover.

The population of the Florida Keys is over 85,000 based on 1990 census projections. The Keys rely heavily on their tourist-based economy and the health of the marine and upland resources factors heavily in individual decisions to visit the Keys. During a recent study (1995-96), it was determined that approximately 3 million visitor trips annually are made to the Keys totally over 16 million person days of time spent while visiting. These visitors generate over 1.1 billion dollars in direct output and income that result in the creation of over 13,600 jobs within the Keys economy.

The shallow water environments of the Keys and Florida Bay support extensive nursery grounds for a variety of important commercial fish and crustaceans species most of which are also harvested in the area. Among important economic species, pink shrimp, spiny lobster, and stone crab landings alone brought over 125 million dollars to the local Keys economy in 1994.

The Florida Keys were designated as an Area of Critical State Concern by the State of Florida in 1975. In 1987 the State also designated the waters surrounding the Keys as Outstanding Florida Waters. There are a number of important marine, wildlife, and ecological management areas in and surrounding the Florida Keys. These include the Florida Keys National Marine Sanctuary, which encompass approximately 2,800 nautical square miles, Biscayne National Park, and the Dry Tortugas National Park and Monument. The Fish and Wildlife Service manages four important refuge areas in and surrounding the Keys; these include the Key Deer, Great White Heron, Key West, and Crocodile Lakes National Wildlife Refuges. There are at least five state parks, John Pennekamp Coral Reef, Long Key, Curry Hammocks, Bahia Honda, and Fort Zachary Taylor State Parks; four state aquatic preserves, including Biscayne, Card Sound, Lignum Vitae, and Coupon Bight, Aquatic Preserves; two state botanical sites, including Lignum Vitae State Botanical Site; one state historic site, and one state geologic site.

Sub-region 6 lies at the southern extreme of the South Florida Ecosystem. The many diverse habitats of the Sub-region constitute a closely coupled interface between the land and water areas of the Region.

Inland areas of south Florida are the source of fresh water to the coastal areas, including Florida and Biscayne Bays, Manatee Bay, and Barnes, Card, and Blackwater Sounds. Aside from the natural influences of the freshwater drainage through these areas, a number of water management canals discharge to these receiving waters. These serve as a direct link to upstream areas and are a source of nutrient and contaminant contributions from urban and agricultural areas.

The influences of Sub-region 3, particularly Florida Bay, on the water quality of the Florida Keys and the adjacent reef tract are of major concern. Though, there appears to be some improvement in the state of Florida Bay, algal blooms and turbid water conditions persist. These influences may have their most dramatic impacts at the coral reef. The reef tract is characterized by coral species which do not tolerate high turbidity or nutrient loads.

Southern Dade County ground water is the source of potable water for the Florida Keys; thus, wellfield contamination problems or salt water intrusion in Sub-region 3 impact Sub-region 6.

The Florida Keys provides linkages to the broader continental and Caribbean regions. As is well noted in the Fall and Winter, migratory birds utilize the Keys as a final "jumping-off point" to the Caribbean, and Central and South America. Endangered sea turtles migrate broadly within the greater Atlantic and Caribbean Regions, often frequenting the Keys area and nesting on their beaches. Valuable commercial and recreational fish species, particularly those that use the Straits of Florida and the Gulf Stream, also establish important linkages to the South Florida, Atlantic, Caribbean, and Gulf Regions.

The upland, near-shore, and coral reef environments of Sub-region 6 have all been altered by anthropogenic influences within and external to the sub-region.

Integral to the improvement of the Sub-region is the improvement of Sub-region 3, the Everglades and Florida Bay. This is essential to the ultimate improvement in Sub-region 6. The Sub-region includes the southern edge of Florida Bay where stresses such as extensive seagrass die-off, diminished water clarity, phytoplankton blooms, the death of mangroves on isolated mangroves islands, and reduced numbers of both benthic species and notable commercial species are all a concern.

Extensive areas of upland habitat have been destroyed or fragmented by development in the Keys. Little additional, development is currently allowed within larger intact areas at this time. However, for the sake of improved management, it is important to provide these areas with an enhanced level of protection. The tropical hardwood forests and pine rocklands of the Keys are significant remnants of historically more expansive plant communities found in the South Florida ecosystem. Threats from exotic plant invasion are significant in this light. The influences of exotic plant species intrusion and the poaching of endangered plant species, particularly bromeliads and orchids, has a significant impact on the current and future quality of these resources. Exotic plant pests, including Australian pine, Brazilian pepper, and Asiatic colubrina represent nearly 10 percent of the land cover in the Keys. Land acquisition and active land management, including exotic removal programs, are key components of necessary protection efforts in the Sub-region.

Nearshore components of the Sub-region are receiving a variety of stresses as a result of direct and indirect impacts. The Keys have grown from a rural community to a suburban or even urban setting through the last fifty years. Antiquated wastewater management practices reminiscent of its rural past still predominate. There are over 20,000 permitted on-site septic systems in the Florida Keys and as many as 9,000 unpermitted cesspits. The nutrient impacts of either system influence the heath of the Keys nearshore waters. Improvements in current wastewater management practices are essential.

The Keys shallow water resources, including seagrass meadows and algal flats, are being impacted directly by boaters who cross these areas either unwittingly or intentionally. Some 30,000 acres of seagrass have been prop scarred by boaters in the Florida Keys area. These are impacts that may be managed and improved by appropriate use of education, channel marking, zoning, and enforcement measures.

The coral reef is receiving both external and internal impacts in the Sub-region. The health of the coral ecosystem is in question as a result of the influences of Florida Bay, Caribbean and global influences, and the direct impacts of humans. Significant study is still necessary to determine the proportional cause and effect relationships. However, efforts to manage access to the most utilized areas, through marine zoning and use restrictions should help improve the coral reef tract area.

RESTORATION OBJECTIVES:

The restoration objectives of critical importance to Sub-region 6 have been identified by the Working Group and are listed as follows:

• Restore water budgets, circulation dynamics, and historic salinity patterns to Florida Bay.
• Restore water quality and nutrient cycling in Florida Bay and in nearshore and confined waters.
• Restore seagrass, mangrove, coral reef, and other habitats.
• Preserve and restore upland biological communities.
• Protect and restore endangered species.

Important restoration projects in progress or proposed for the Sub-region are identified on the following pages: