FIGURE 2.
A schematic bipartite network of four ECM plant species (pA, pB, pC, pD) and their three ECM fungal symbionts (f1, f2, f3). The degree in the bipartite network is kpi for a plant species pi and kfj for a fungal species fj. The average degree of the fungal partners of a given plant species pi is cpi. (A) Displays the degrees of plant and fungal species and the average degree of the fungal partners of each plant species. (B) Illustrates the detailed calculation of cpA. (C) Illustrates the plant projected network composed of indirect (two-step) links through fungi, i.e., plant–plant links mediated by shared fungal symbionts. The number of plant species linked to a given plant species through spi fungi-mediated links is lpi. The numbers of indirect (two-step) links between a given plant species pi and the other plant species is spi. In all panels, dotted, broken and continuous lines show plant–plant links made by the fungal species f1, f2, and f3, respectively. The roles played by plants and fungi can be inverted to analyze the network from a fungal perspective.