How and why have landscape patterns changed in the Everglades: The ecological underpinnings of restoration

Congress approved the Comprehensive Everglades Restoration Plan (CERP) in 2000  “to restore, preserve, and protect the South Florida ecosystem…”.  The science that was the basis for CERP was mostly hydrologic, while the biological, ecological and landscape underpinnings were mostly qualitative. Government agencies now have to conduct scientific “catch-up” to make sure that plans are sound and likely to succeed. Tools such as landscape pattern analysis, the use of macrocosms, (for example, the Loxahatchee Impoundment Landscape Assessment), and large-scale landscape manipulations such as the Decomp Physical Model will provide insight into the current patterning. These landscape patterns tree islands, which provide habitat for a wide variety of flora and fauna. The highest tree islands are only slightly above mean annual maximum water levels, so that tree islands with their less flood tolerant vegetation may be the most sensitive component to hydrologic restoration. Water management practices during the early 20^th century caused these biodiversity hotspots to disappear and the landscape to convert to marsh and open water. Only 40% of the Water Conservation Area-3 islands observed in 1940 aerial photos remain. Tree island loss around selected stage gages, and a regional analysis from 1940 until 1995 indicate three possible causes: 1) loss due to regular depths less than -1.0 ft; 2) loss due to persistent depths greater than 2.0 ft; and 3) significant loss due to extended periods when depths were both below -1.0 ft and above 2.0 ft. Ecological patterns indicate options for better hydrologic management for restoration.