Consequences of ecological aggregation in general equilibrium analysis of perturbed ecosystems

A computable general equilibrium (CGE) model is linked with a spatially explicit model of the Lake Michigan ecosystem to assess welfare impacts of the current threat of Bigheaded carp, a non-indigenous aquatic invasive species (AIS) projected to have spatially explicit and species-specific impacts on the ecosystem. Disaggregating to model spatial decisions and spatially explicit species compositions in general equilibrium frameworks comes at a cost of additional complexity and data requirements. Whether these investments are worth the effort over extant ecological aggregations is the focus of this analysis, as typical methods consider spaceless aggregations across locations and aggregate over species. Here, the implications of aggregating over space and/or species are quantified. Results signal welfare losses from the bigheaded carp invasion, and that aggregating over one/both dimensions may miss important bioeconomic tradeoffs especially with respect to species.