The expansive coastal wetlands and freshwater marsh of south Florida are a result of the very slow relative rise of sea level during the past 3200 years (average rate of 4 cm/100 years). Prior to that time, relative sea level was rising at a rate of 23-50 cm/100 years - too fast for coastal swamp, marl, or sand environments to stabilize along south Florida's coastlines. The establishment of a broad, coastal wetland during the past 3200 years has provided a natural barrier to marine waters and permitted freshwater environments of the Everglades to expand. From 1930-1990, relative rise in sea level for south Florida has averaged 3-4 mm.yr-1 (equivalent to 20-40 cm/100 years). This rate is 6-10 times that of the past 3200 years and is triggering dramatic changes in the coastal wetland communities, including accelerated erosion of shore margins, landward encroachment of marine wetlands, and saltwater encroachment of surficial and ground water. -from Authors
