Ecological Models: Model Development and Analysis

The development of a model requires clear agreement on its purpose and context, defined in consultation with relevant stakeholders. The process of achieving agreement is iterative, with continual refinement of the purpose and objectives as the modelers and stakeholders learn more about the system modeled and the scope for using the model. From there, conceptual models can be developed to guide the choice of model features and families and to help determine how model structure and parameter values are to be found. Performance criteria can then be developed, geared to the model purpose, context and structure, and available data. Once constructed, the model must be subjected to calibration, model testing, quantification of uncertainty, and evaluation of its effectiveness. At any point it may be necessary to revisit and revise earlier steps as new information becomes available. This article discusses a 10-step procedure for model development and evaluation in the context of two ecological models developed in parallel for an Australian wetland system. Adoption of minimum standards of model development, as outlined in this article, will lead to more purposeful and credible ecological models.