This chapter addresses the problem of how individuals are distributed in space and time. Space is assumed to consist of areas differing in terms of profitability, some being more productive or otherwise of higher quality than others. The theory of ideal free distribution (IDF), or in more general terms resource matching, was developed to address the issue of how individuals are expected to be distributed across areas differing in availability of relevant resources. We shall first discuss resource matching in terms of distribution of foragers over their renewable resources under various circumstances. We end by extending our exploration at the level of population dynamics in areas with differing carrying capacities.

Ideal free distribution

Ecology is the scientific exploration of the distribution of individuals and species in space and time (Krebs 1972). This is also the central theme of this chapter. We are specifically addressing the following question: how should individuals be distributed in an environment consisting of a number of habitat patches varying in resource availability? This is a question studied in the framework of the ideal free distribution (Fretwell and Lucas 1970; Fretwell 1972; or the theory on resource/habitat matching in general, Parker 1974; Morris 1994). According to the IFD theory (fig. 10.1), assuming virgin habitats, the first arriving individual should occupy the most rewarding area. From then on, its presence and activity there devalue that particular habitat patch. The next arrival should also go to a place where the highest reward can be extracted.