Salt-marsh ecogeomorphological dynamics and hydrodynamic circulation
The overall dynamics of intertidal environments are governed by complex interactions between their ecological and geomorphological components. A more comprehensive understanding of such dynamics and their predictive modeling can only be achieved through the description of the feedback coupling hydrodynamics and sediment transport on one hand and ecological processes on the other. Toward the goal of a comprehensive theoretical framework describing the large-scale, long-term evolution of the intertidal landscape, we describe an ecomorphodynamic model which allows the investigation of the long-term evolution of tidal networks, the adjacent marsh platforms, and the effects of vegetation competition. On the basis of observational indications regarding the different time scales governing the various landscape-forming processes, the model decouples the initial rapid network incision from its subsequent slower elaboration and from the ecomorphological evolution of intertidal platforms. The planimetric development of tidal channel networks coupled to the vertical accretion of the adjacent marsh platform, explicitly accounting for the vegetation distribution and dynamics, in the face of changing sea level rise and sediment supply is modeled and analyzed. The resulting ecomorphodynamic model reproduces the ecogeomorphic patterns typical of intertidal environments and is used to explore the response of tidal ecogeomorphologies to different scenarios of changing sea level, incoming sediment concentrations, and halophytic vegetation competition. Complex network structures and tidal patterns meeting distinctive statistical properties of actual network structures and several observed characteristics of ecological and geomorphic relevance are reproduced by the model.
