Modeling spatial dynamic ecological processes with DEVS-Scheme and geographic information systems.

The objective of this work is to introduce and illustrate the potential of discrete event, hierarchical modular models for simulating spatial dynamic ecological processes in geographic information systems (GIS). The knowledge based discrete-event simulation environment (DEVS-Scheme) associates stand-alone discrete event models with spatial locations represented in a GIS data base, and couples those models in a coherent manner. The dynamic models can then process spatially distributed information available in a GIS data base, and update it through time. The models also can receive external updated information at any moment, due to the continuous time nature of discrete event specifications. The proposed approach facilitates the representation of reality at several levels of resolution, with model components organized in a hierarchical structure and information flow implemented in the form of message passing. These capabilities are illustrated with two applications. The first is a multi-scale spatial succession model of a wet sclerophyllous forest subject to recurrent fires, and the second is a fire growth model