The connections between food web structure and food web stability have preoccupied ecologists for at least half a century. Initially, the 'conventional wisdom' was that increased complexity within a community leads to increased stability; that is, more complex communities are better able to remain structurally the same in the face of a disturbance such as the loss of one or more species. Increased complexity, then as now, was variously taken to mean more species, more interactions between species, greater average strength of interaction, or some combination of all of these things. Elton (1958) brought together a variety of empirical and theoretical observations in support of the view that more complex communities are more stable (simple mathematical models are inherently unstable, species-poor island communities are liable to invasion, etc.). Now, however, it is clear his assertions were mostly either untrue or else liable to some other plausible interpretation. (Indeed, Elton himself pointed out that more extensive analysis was necessary.) At about the same time, MacArthur (1955) proposed a more theoretical argument in favor of the conventional wisdom. He suggested that the more possible pathways there were by which energy passed through a community, the less likely it was that the densities of constituent species would change in response to an abnormally raised or lowered density of one of the other species.
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