Algorithmic reconstruction of trophic networks from open-access species lists reveals key organisms in real ecosystems
Fig 6
(A). The number of semi-independent modules remains relatively low (around 4) and constant for most ecosystems. (B). The average clustering (CLUST) increases in large ecosystems. (C). The average modularity (MOD) decreases in large ecosystems. (D). Some of the modularity-related measures are linearly correlated as indicated by the corresponding Pearson’s correlation coefficient. Anticorrelation between CLUST and MOD suggests that modules become less independent as ecosystems grow in size. (E-F). Two case examples of modular structure in our dataset: (E). Naikaikemi (Japan, N = 28), and (F). Whooping Crane (USA, N = 36). Colors represent the optimal division maximizing modularity, dashed line separates carnivores-scavengers from the remaining organisms and dashed nodes represent “bridge” species between modules. (G). An idealized network showing how the modules are, in general, organized across networks.