A Stochastic Theory of Community Food Webs: I. Models and Aggregated Data
Abstract
Three recently discovered quantitative empirical generalizations describe major features of the structure of community food webs. These generalizations are: (i) a species scaling law: the mean proportions of basal, intermediate and top species remain invariant at approximately 0.19, 0.53, and 0.29, respectively, over the range of variation in the number of species in a web; (ii) a link scaling law: the mean proportions of trophic links in the categories basal-intermediate, basal-top, intermediate-intermediate, and intermediate-top remain invariant at approximately 0.27, 0.08, 0.30 and 0.35, respectively, over the range of variation in the number of species in a web; and (iii) a link-species scaling law: the ratio of mean trophic links to species remains invariant at approximately 1.86, over the range of variation in the number of species in a web. This paper presents a model, the only successful one among several attempts, in which the first two of these empirical generalizations can be derived as a consequence of the third. The model assumes that species are ordered in a cascade or hierarchy such that a given species can prey on only those species below it and can be preyed on by only those species above it in the hierarchy.
- Publication:
-
Proceedings of the Royal Society of London Series B
- Pub Date:
- June 1985
- DOI:
- 10.1098/rspb.1985.0042
- Bibcode:
- 1985RSPSB.224..421C