Virtual experimentation: Conceptual models and hypothesis testing of ecological scenarios

Models intended to describe the mechanisms involved in ecological systems (conceptual models) are being increasingly employed to make predictions, and evaluate the effect of different scenarios. We propose a framework for employing conceptual models in hypothesis testing of ecological scenarios for the case external entities have an additive effect on treatment entities. The use of conceptual models to test the effect of scenarios is referred to as 'virtual experimentation'. The rationale of virtual experimentation is compared and contrasted with field experimentation. The analysis of the effect of acidic deposition on the site index of a forest stand is employed to illustrate this methodology. A conceptual forest growth model based on the pipe theory and the self-thinning rule is employed to conduct this analysis. In this virtual experiment we assume that the effect of external entities on treatments is additive. It is argued that this study proposes a valuable method for testing the effect of ecological scenarios employing conceptual models.