Species abundance and asymmetric interaction strength in ecological networks

Diego P. Vázquez, Carlos J. Melián, Neal M. Williams, Nico Blüthgen, Boris R. Krasnov, Robert Poulin

    Research output: Contribution to journalArticlepeer-review

    498 Scopus citations


    The strength of interactions among species in a network tends to be highly asymmetric. We evaluate the hypothesis that this asymmetry results from the distribution of abundance among species, so that species interactions occur randomly among individuals. We used a database on mutualistic and antagonistic bipartite quantitative interaction networks. We show that across all types of networks asymmetry was correlated with abundance, so that rare species were asymmetrically affected by their abundant partners, while pairs of interacting abundant species tended to exhibit more symmetric, reciprocally strong effects. A null model shows that abundance provides a sufficient explanation of the asymmetry structure in some networks, but suggests the role of additional factors in others. Although not universal, our hypothesis holds for a substantial fraction of networks analyzed here, and should be considered as a null model in all studies aimed at evaluating the ecological and evolutionary consequences of species interactions.

    Original languageEnglish
    Pages (from-to)1120-1127
    Number of pages8
    Issue number7
    StatePublished - 1 Jan 2007

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics


    Dive into the research topics of 'Species abundance and asymmetric interaction strength in ecological networks'. Together they form a unique fingerprint.

    Cite this