Figure 5.15. The connectivity of the StMartin island food web  is illustrated in two directed graphs formed by the hierarchically ordered layers A to F. The trophic species of each layer (numbered after ) can eat only downstream species and, in few cases, species of their own layer. The connectivity shown explicitly in the upper (unweighted) graph is that between the pairs of neighboring layers only. The edges of the lower (weighted) graph show the total number of interactions between all pairs of layers. The calculations of the complexity measures of the St. Martin's food web, however, are made proceeding from the entire directed graph with its 42 species and 205 directed interactions.
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