VIRTUAL EXPERIMENTATION - CONCEPTUAL MODELS AND HYPOTHESIS-TESTING OFECOLOGICAL SCENARIOS

Models intended to describe the mechanisms involved in ecological syst ems (conceptual models) are being increasingly employed to make predic tions, and evaluate the effect of different scenarios. We propose a fr amework for employing conceptual models in hypothesis testing of ecolo gical scenarios for the case external entities have an additive effect on treatment entities. The use of conceptual models to test the effec t of scenarios is referred to as 'virtual experimentation'. The ration ale of virtual experimentation is compared and contrasted with field e xperimentation. The analysis of the effect of acidic deposition on the site index of a forest stand is employed to illustrate this methodolo gy. A conceptual forest growth model based on the pipe theory and the self-thinning rule is employed to conduct this analysis. In this virtu al experiment we assume that the effect of external entities on treatm ents is additive. It is argued that this study proposes a valuable met hod for testing the effect of ecological scenarios employing conceptua l models. (C) 1997 Elsevier Science B.V.