Modeling Coastal Landscape Dynamics

The process-based coastal ecological landscape spatial simulation model (CELSS) was developed to examine the impact of the natural delta switching cycle, human activities and proposed remedies for coastal erosion of the Atchafalaya/Terrebonne marsh/Mississippi estuary complex. CELSS consisted of 2479 interconnecting square cells, each representing 1 km2 and containing a dynamic ecosystem simulation model which predicted sediment input and output, water exchange and primary production. Model input data consisted of digitized ecosystem system type maps, historical records of canal and levee construction, a weekly record of climatic variables and field measurements of productivity, biomass and nutrient uptake. Calibration was based on ecosystem type maps for 1956-1978, and analysis-of-variance procedures were used for parameter optimization. Although CELSS was expensive to build and run, it predicted 1978 data better than alternative or null models, and linked predicted physical and ecological changes to ecosystem type changes. Specific results were realistic but they could not be generalized for other locations. Future ecosystem type maps are presented under various climate, management, historical and boundary scenarios. Process-based spatial models could be used to evaluate the costs and benefits of major projects and to design optimal coastal management strategies. There are 41 references.