Slide 15 Marshes are wetlands dominated by herbaceous plants rooted in and generally emergent from shallow water that stands at or above the ground surface for much of the year. Marsh ecosystems include bogs, mires, prairies, wet prairies, savannas, wet savannas, reed swamps and swamps. Florida's marshes are characterized by their subtropical location, fluctuating water levels, recurring fires and hard water. Marshes occur anywhere local topography and impermeable soils prevent rapid runoff or infiltration - either near rivers and lakes or in small basins and other depressions. Fire plays a crucial role in the ecology of Florida's marshes by limiting the invasion of woody vegetation, affecting the composition of the herbaceous community, and retarding or occasionally reversing peat accumulation.
Fires also burn dead but undecayed plant material releasing nutrients.
Fires have always been frequent occurrences in Florida's marshes. Everglades peat owes its black color to charcoal from ancient fires. Summer is the natural fire season. Thus natural fires generally occur when soil moisture levels are high and plants are growing. Because organic soils fail to ignite when moisture content is above 65 percent, wet season fires are typically confined to the above water vegetation and seldom consume soil.