The potential for community level evaluations based on loop analysis

In this paper we present results obtained with a computer simulation in which a community, described by Levins in his presentation of loop analysis (Levins, R., 1975, Evolution in communities near equilibrium, in: Ecology and Evolution of Communities, M.L. Cody and J.M. Diamond (eds) (Harvard University Press, Cambridge, Mass.) pp. 16-50), is analysed. We show how our simulation accurately reproduces Levins' calculations and further, (i) how our simulation can be used to answer questions raised by Levins but never answered, (ii) how the simulation can be used to dissect a community in order to analyse the roles played by the various entities, and (iii) how predictions relating to the evolution of this community, proposed by Levins, can be analysed with some interesting and unexpected results. In particular, it becomes clear that discussion of the type of selection that may take place needs to be done in the framework of the community in which it occurs.