Modern ecological assessment requires the projection of future trends in various population and community characteristics, using Geographic Information System (GIS) input data, remote sensing data for animal movements, and a variety of physical model outputs for abiotic components. Linking together these inputs to spatially-explicit, dynamic ecological models requires the use of multiple mathematical modeling approaches. I will describe how we have constructed such a multimodel for use in providing relative assessments of alternative hydrologic plans in South Florida. This multimodel - ATLSS (Across Trophic Level System Simulation) - has been extensively used in the ongoing planning process for Everglades restoration. Interested parties should visit the home page at http://atlss.org/ for more information.