Florida resists simple categorization as a single biome, as its geography creates a complex mosaic of distinct ecological communities. The state acts as a transition zone where temperate species from the north mingle with tropical species reaching their northern limit. This blending of life forms and habitats means Florida is a biodiverse collection of interlinked ecosystems rather than a single biome.
Climatic and Geographical Drivers
Florida’s unique ecology is fundamentally shaped by its latitude and physical geography, which together create a climate ranging from humid subtropical to tropical. The state’s long peninsular shape means no part is far from the ocean, moderating temperatures and providing abundant moisture. This location places Florida in a critical buffer zone where northern and southern species overlap.
The state averages nearly 54 inches of rainfall annually, with a distinct wet season running from May through October that drives the hydrological cycles of its interior wetlands. Conversely, the mild, drier winter and spring create conditions that allow for natural fire regimes in the upland ecosystems. The state’s extreme flatness, with much of the land at an elevation of under 12 feet, means that slight changes in topography or water table create entirely different habitats. This low relief causes water to move across the landscape in slow-moving sheets rather than draining quickly.
Water-Dominated Wetland Ecosystems
The defining feature of Florida’s interior is the dominance of wetlands, which are controlled by long periods of standing water known as the hydroperiod. The Everglades, often called the “River of Grass,” is a vast, slow-moving sheet of water originally flowing south from Lake Okeechobee. This system is characterized by a “ridge and slough” landscape where slight elevation differences create two distinct habitats.
Sawgrass marshes, dominated by a sharp-edged sedge, grow on slightly higher ridges. These ridges are interspersed with deeper channels called sloughs, which can remain flooded for nearly 12 months. The sloughs serve as main avenues of water flow and are naturally protected from fire, supporting submerged and floating aquatic plant life.
Cypress swamps are another characteristic wetland, often forming in circular depressions called cypress domes. The distinctive dome shape is a result of the water depth, as trees grow taller in the deeper center where the hydroperiod is longest. An underlying layer of impervious clay or a natural limestone depression traps rainwater, creating these long-lasting, isolated wetlands. The acidic water in the deeper parts of the dome center often precludes tree growth entirely, forming a pool that provides a year-round refuge for aquatic animals.
Upland and Fire-Maintained Terrestrial Ecosystems
Florida’s higher ground ecosystems are defined by dry, sandy soils and a dependence on regular fire for their long-term survival. Pine flatwoods are the most extensive of these communities, dominated by species like longleaf or slash pine over a dense understory of saw palmetto and grasses. These communities are pyrophytic, meaning they require frequent, low-intensity fires to suppress hardwood invasion.
The unique Florida Scrub community is a relic habitat found primarily on ancient sand ridges, such as the Lake Wales Ridge. These ridges represent former coastal dunes that remained above sea level during interglacial periods. This long-term isolation has resulted in a high degree of endemism, meaning many species, including the Florida scrub-jay and the legless sand skink, are found nowhere else in the world. The deep, excessively well-drained sand creates a xeromorphic environment, effectively a desert in a high-rainfall climate.
Hardwood hammocks, conversely, are fire-intolerant environments composed of dense, broad-leafed trees that create a shaded, moist microclimate. They typically grow on slight rises, which protects them from minor flooding. The decomposition of vegetation on the underlying limestone bedrock creates a weak acid that dissolves the rock, forming natural depressions that fill with water. These water-filled “moats” act as a barrier, protecting the hammock’s fire-sensitive species from the periodic wildfires that sweep through the adjacent pinelands and scrub.
Coastal and Marine Ecosystems
The state’s extensive coastline is fringed by ecosystems uniquely adapted to saltwater and the dynamic forces of the ocean. Mangrove forests are a defining feature of the tropical and subtropical coast, typically found south of the state’s winter freeze line. These salt-tolerant trees stabilize the shoreline with their dense, tangled root systems, reducing erosion and absorbing storm surge energy.
The sub-aquatic roots of the mangroves provide a critical nursery habitat for juvenile fish, shrimp, and crustaceans that support Florida’s commercial fisheries. North of the range where mangroves can survive winter freezes, the intertidal zone is dominated by salt marshes. These communities are composed of salt-tolerant grasses and herbs, such as needlerush, which play a similar role in filtering water and stabilizing sediments.
Offshore, the Florida Keys are home to the only living coral barrier reef in the continental United States, extending over 220 miles from North Key Largo to the Dry Tortugas. This complex ecosystem supports over 80 species of corals and more than 600 species of fish, rivaling the biodiversity of terrestrial rainforests. The reef structure itself is built over thousands of years by the calcifying skeletons of tiny coral polyps, forming an indispensable habitat that links with the nearby seagrass beds and mangroves.