The Ecosystem Concept and Linking Models of Physical-Chemical Processes to Ecological Responses: Introduction and Annotated Bibliography

SUMMARY AND COMMENT: The linking of models of physical-chemical drivers (engineer-ing models) to models of biotic response (ecological models) is an exercise that must carefully address the issues of hierarchy, scale (in time and space), frameworks of reference, and curren-cies used by the candidate models. To understand the hurdles that must be surmounted in creat-ing model linkages and to be a contributor to the model linkage effort, practitioners should have a basic understanding of ecosystem modeling and the ecosystem concept. The literature review and bibliography provided here are intended as an entry point for gaining an introductory grounding and a basic appreciation for this topic. In well-conditioned situations, it is clearly possible and beneficial to link engineering models of drivers (the physical-chemical environment) to higher-level models of ecological response. Two examples (Peoria Lake and Richard B. Russell Lake) where this was successful for specific, restricted purposes are shown. The authors have also seen an example where such a linkage is proving extremely difficult (Chesapeake Bay) and can easily envision situations where it would be impossible or meaningless. Connections in two directions (to and from the biota), or with multiple hierarchical levels are far more difficult and are less likely to be successful without sub-stantial changes to the underlying models. The actual details of transferring data from one model to another are beyond the scope of this presentation, but can be a tedious undertaking; one that may require additional computer code and ecological research to allow a meaningful connection. Experts who represent both sides of the proposed model linkage and the underlying ecological sciences must be involved in any linkage attempt. These experts will serve to (1) evaluate and resolve the conceptual issues involved in the linkage, and (2) design the actual linkage