Resource-consumer models and the biomass conversion principle

In the search for a unified basis for constructing food-web models, the long-standing discrepancy between biomass conversion (BC) and individual survival (IS) modeling has been revitalized by Ginzburg (J. Anim. Ecol. 67 (1998) 325) and Berryman (J. Anim. Ecol. 68 (1999) 1263) in the context of resourceeconsumer interactions. In this work, the principles underlying the confronting approaches are summarized and the criticisms addressed against each. Also, it is argued that the achievement of a single theory of resourceeconsumer ecology could benefit from this debate by incorporating key elements of both approaches. A logical procedure is suggested to build simple continuous resourceeconsumer models that follow the principle of biomass conversion, possess structural homogeneity, and distinguish the effects of depletable and fixed resource availability. Additionally, a new conversion function and a general Holling type extraction function ( functional response) are introduced. Finally, it is shown that some well known IS models can be obtained as special cases of a general BC model.