Everglade National Park

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Chapter 3. SITE DESCRIPTION

c - Biological features

Habitats

Brief description of dominant and particular habitats (marine and terrestrial)*: List here the habitats and ecosystems that are representative and/or of importance for the WCR (i.e. mangroves, coral reefs, etc):


Florida Bay in Everglades National Park has been identified as a habitat area of particular Concern (HAPC). Mangrove-covered islands and submerged aquatic vegetation in the bay provide important habitat for many of the fisheries, such as pink shrimp, red drum, and spiny lobster. Essential fish habitat in Everglades National Park is composed of estuarine waters and substrates (mud, sand, shell, rock, and associated biological communities) and includes submerged vegetation (seagrasses and algae), marshes and mangroves, and oyster shell reefs or banks.

Some of the dominant and “essential” marine habitats in the park include:
• submerged aquatic vegetation (seagrasses)
• intertidal vegetation (marshes and mangrove)
• benthic algae
• coral reefs
• sand/shell bottoms
• soft bottoms
• pelagic communities, oyster reefs, and shell banks
• hard bottoms

These habitats provide forage, nursing, and spawning areas for species such as shrimp, snappers, spiny lobster (Panularis argus), reef fish, and mackerels.

Seagrass meadows provide substrates and environmental conditions that are essential to the feeding, spawning, and growth of several managed species. Juvenile and adult invertebrates and fishes, as well as their food sources, use seagrass beds extensively. Mangroves and marshes provide essential habitat for many managed species, serving as nursery grounds for larvae, juveniles, and adults. Mangrove habitats (particularly riverine, overwash, and fringe forests) provide shelter for larvae, juvenile, and adult fish and invertebrates.

In addition, mangroves and marshes provide dissolved and particulate organic detritus to estuarine food webs. Because of this dual role as habitat and as food resource, mangroves are important exporters of material to coastal systems. Mangroves also export materials to terrestrial systems by providing shelter, foraging grounds, and nursery/rookery areas for terrestrial organisms. The root system binds sediments, thereby contributing to sedimentation and sediment stabilization. Corals and coral reefs support a wide array of corals, finfish, invertebrates, plants, and microorganisms. Hard bottoms and hard banks often have high species diversity but may lack reefbuilding (hermatypic) corals, the supporting coralline structure, or some of the associated biota. Hard bottoms are usually of low relief and on the continental shelf; many are associated with relic reefs, where the coral veneer is supported by dead corals. In deeper waters, large, elongated mounds (called deep-water banks) that are hundreds of yards in length often support a rich fauna compared with adjacent areas.
Benthic algae occur in both estuarine and marine environments and are used as habitat by managed species, such as the queen conch and early stages of the spiny lobster. Threatened sea turtles use some benthic algae species as food. Invertebrate species, including mollusks and crustaceans, inhabit this area and are eaten by various fishes. Sandshell and soft bottom habitats are common throughout Florida and the Caribbean. These habitats are characterized as being extremely dynamic. However, buffering by reefs and seagrasses allows some salt-tolerant plants to colonize the beach periphery. Birds, sea turtles, crabs, clams, worms, and urchins use the intertidal areas. The sand/mud subsystem includes all non-live bottom habitats or those with a low percent of cover (less than 10%). Sandy and mud bottom habitats are widely distributed and are found in coastal and shelf areas. These areas include inshore, sandy areas separating living reefs from turtle grass beds and shorelines, rocky bottoms near rocky shorelines, and mud substrates along mangrove shorelines. Sand/shell habitat is used for foraging by many fishes, such as mojarras, and as substrate for solitary corals. The pelagic subsystem includes the habitat of pelagic fishes. Pelagic habitat is associated with open waters beyond the direct influence of coastal systems.

In general, primary productivity in this zone is low and patchily distributed, being higher in nearshore areas as opposed to offshore areas. The pelagic system is inhabited by the eggs and larval stages of many reef fishes, highly migratory fishes, and invertebrates, some of which, like the spiny lobster, are commercially important. Oyster and shell essential fish habitat is defined as the natural structures found between (intertidal) and beneath (subtidal) tide lines. These structures are composed of oyster shell, live oysters, and other organisms that are discrete. Oysters have often been described as the “keystone” species in an estuary, and they provide substantial surface area as habitat. Oyster communities are critical to a healthy ecosystem, because oyster reefs remove, via filter feeding, large amounts of particulate material from the water column and release large quantities of inorganic and organic nutrients. The oyster reef as a structure provides food and protection and contributes to critical fisheries habitat. Whereas essential fish habitat must be described and identified for each species and life, habitat areas of particular concern are identified on the basis of the condition of the habitat.

Detail for each habitat/ecosystem the area it covers:

Marine / coastal ecosystem categories
Detail for each habitat / ecosystem the area covers
Size (estimate) Description and comments
unit Area covered
Mangroves
Mangroves ha 92600 The Gulf of Mexico Fisheries Management Council identified six areas in Everglades National Park — Florida Bay; Lake Ingraham; Whitewater Bay; Cape Sable to Lostman’s River; Lostman’s River to Mormon Key; and Mormon Key, up to and beyond the park boundary, to Caxambas Pass — that contain essential fish habitat dominated by mangrove islands and mangrove forests that include marsh areas and areas of submerged aquatic vegetation (seagrass). The complex of six areas is referred to as the Florida Bay and Ten Thousand Islands area. Mangroves in these areas cover approximately 926 km2, and marsh areas cover about 664 km2. Cape Sable contains about 66% of the tidal marsh and greater than 60% of the mangroves in these areas. Submerged vegetation in the area totals nearly 661 km2, mostly within Florida Bay. The approximate sizes and percentages of each habitat type can be found in the attached map of Everglades’ ecosystems included as an Annex.
Terrestrial ecosystems
Size (estimate)
unit Area covered
Wetlands
Marsh sq.km 664
Submerged vegetation sq.km 661