An Input-output Economic Model Integrated Within a System Dynamics Ecological Model: Feedback Loop Methodology Applied to Fish Nursery Restoration

While environmentally extended input-output (IO) models are commonly used for capturing interactions between ecosystems and economic systems, this kind of modelling cannot reflect interactions within the ecosystem. Isard's (1968) model has been the only exception. He entered interactions occurring within the ecosystem into IO. Nevertheless, given the linearity of IO, he could only analyze environmental issues in a linear fashion. We propose an alternative that reverses Isard's model types: the economic system is modelled within the ecosystem (not the contrary), as one of the ecosystem's components. To demonstrate its feasibility, we develop an ecological-economic model by integrating conventional economic IO within system dynamics (SD). After describing the methodological issues, we “test” the IO/SD model on ecological and economic data by applying it to the destruction and restoration of the Seine Estuary, France, where Common soles live. Our model brings insight into the consideration of feedback loops in the modelling of interactions between the ecosystem and the economic system. We believe such a tool may be of help to decision makers in mixing economic and environmental issues like, in our application case, fish habitat and harbour development.