Fig. 1
From: Identifying a common backbone of interactions underlying food webs from different ecosystems
Network alignment and identifying a backbone of interactions. a An example of the optimal alignments between three simple networks. The red circles, green triangles, and blue squares represent the species in each network, and the arrows indicate the direction of energy flow between those species. The dotted lines characterize the pairings of species in the three alignments between networks. b Given the alignments in a, we rank species according to the average role similarity that they present across their pairings. The top panel shows the actual average role similarity, and the bottom presents the alignment transitivity of those same species. The best-aligned species from the red network is species c, whereas the worst-aligned is species d. The species in the blue and green networks to which species c is paired are also paired, which implies that the alignment transitivity of c is 1. In contrast, the alignment transitivity for species d is 0 because there are no paired species in the blue and green networks to which d is paired. c Given the alignments in a, we can also identify the backbone of interactions for each network. Here, the dark links are those that present the maximum overlap across network alignments and therefore characterize the backbone of interactions. The lighter links represent the periphery of such backbone
