Algorithmic reconstruction of trophic networks from open-access species lists reveals key organisms in real ecosystems
Fig 7
Robustness to loss of taxonomical resolution.
(A). Relationship between species richness and taxonomic richness across ecosystems, shown for multiple hierarchical levels (number of genera, families, orders, classes, and phyla). Each point corresponds to an ecosystem. This panel shows how the number of different genera in the ecosystems (each representing functionally similar organisms) escalates in proportion to the number of species N, which helps explain why our method is relatively insensitive to moderate taxonomic rarefactions (see next panels). (B) Taxonomic rarefactions were introduced by progressively collapsing species into higher taxonomic ranks (species → genus → family → order), producing genus-, family- and order-levels nodes. The panel illustrates how species belonging to the same genus (same color) in a schematic species-level network collapse into a single node in the corresponding genus-level network. For each collapsed node, body size was set to the mean of member species, and diet/habitat were aggregated as the union of their categories. After each taxonomic rarefaction, the trophic networks were recalculated, and their topological features compared with the species-level network. (C). Most topological descriptors remain, at least up to the family rank, within certain confidence interval (defined as the mean () ± the variance (σ) of that descriptor in the species-level network). (D). Many of the links in the networks constructed using medium taxonomic ranks (orange) remain similar to the species-level networks (yellow lines and Fig 2A). (E). Many above-species networks retain the scale-free architecture of the original, species-level networks (yellow lines and Fig 2B).