Simulating invasions in fragmented habitats: theoretical considerations, a simple example and some general implications

This contribution discusses two entirely different methodologies for spatially explicit modeling of population dynamics. A hybrid Petri net and a partial differential equation model are used to study the intrusion of a non-endemic species into patched habitats. A detailed comparison of both models based on an application for the Galápagos archipelago in terms of simulation results, methodology, as well as structure shows how different building blocks of ecological models can be. Results of the investigation give a detailed insight into the problem of scaling ecological models and the core question of what processes should be considered in which scale in terms of space, time or complexity and show that model structure depends on spatial configuration, and on the landscape pattern of the investigation area.