Restoration of the Everglades is a multi-objective, multi-scale, multi-agency program that requires numerous computer models to test alternatives, understand ecosystem processes, and evaluate restoration performance. Landscape models used for Everglades restoration include hydrologic models, transition probability models, gradient models, distributional mosaic models, and individual-based models. As tools for restoration feasibility and as the backbone of the policies that will drive Everglades restoration for the next 20 years, it is critical that a wide audience evaluate the strengths and weaknesses of six landscape models. Simulations of historic hydropatterns and current hydropatterns, based mostly upon sheet-flow equations and canal-flow equations, respectively, have been the realm of the Natural Systems Model (NSM) and the South Florida Water Management Model (SFWMM). Despite a lack of biology in these two models, a comparison of their spatial output became the basis for the Comprehensive Everglades Restoration Plan (CERP) approved by the US Congress in October, 2000. SAWCAT, a transitional probability model, was based upon an analysis of the patchiness of cattail (Typha) and sawgrass (Cladium) cells in association with levees, water depth, and phosphorus. This statistical approach was used to predict the amount of sawgrass that would be converted to less desirable cattail, if phosphorus runoff patterns to the Everglades remained constant. The Everglades Water Quality Model (EWQM), a mass-balance gradient approach used to track phosphorus according to a simple net phosphorus removal coefficient, was used to design Storm Water Treatment Areas (STA) and to evaluate where and when phosphorus ‘thresholds’ would be exceeded under various hydrologic restoration plans. The Everglades landscape Model (ELM), a complex distributional mosaic model, used site-specific biogeochemical mechanisms and mass-balance to control energy and material flows, and to predict changes in carbon and phosphorus structure of the soil, water, and plant communities as a result of modified water deliveries to the Everglades. The Across Trophic Level Spatial Simulation (ATLSS), also a distributional mosaic modeling approach, used individual-based rules of behavior to predict animal movement and abundance in relation to hydrologic restoration plans. When these landscape models are combined, they effectively contribute to water management and policy for Everglades restoration. To insure their effectiveness, an applied science strategy provides the framework for their integration into the restoration process.
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Jul 1, 2006
Erik K Webb 
Open Access
