Algorithmic reconstruction of trophic networks from open-access species lists reveals key organisms in real ecosystems
Fig 2
(A). Topological consistency (TC, X-axis) denotes the fraction of replicates of a given ecosystem in which a specific trophic interaction exists.
A large TC indicates highly stable interactions. The Y-axis represents the relative frequency of links (within a given replicate) that exhibit certain TC. As the Figure shows, although most links vary across replicates (facultative interactions), a core, stable sub-network of highly consistent links (specialized necessary interactions) remains stable. Each line represents one replicate of a given ecosystem. (B). The automatically constructed trophic networks show a scale-free degree distribution (DEG). X-axis: number of trophic interactions per node. Y-axis: relative frequency of species having that degree (within a replicate). Line colors as in the (Log scale) insets. Red: all interactions. Purple: only-input interactions (GENnerality). Orange: only-output interactions (VULnerability). Grey and dashed lines: individual (1000) replicates and average distributions under the pure ANM. Insets use logarithmic axes (log-scaled, not log-transformed data) to highlight the scale-free-like structure of the distribution.