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  • Assembly rules and a theory for invasion and extinction in minimal food webs

    Prof. Namiko Mitarai

    Niels Bohr Institute

    Date:10月3日 10:30-

    Place:東京大学駒場キャンパス 16号館107 (map)

    We propose a theory of the evolution of a minimal food web by sequential invasion of new species [1]. Our theory is based on the standard generalized Lotka-Volterra equations, where basal species compete through resource depletion [2]. The considered food webs are “minimal”, as each species only feeds on a single resource, leading to a hierarchical, tree-like food web [1,3]. We prove that at each invasion step there is one uniquely determined outcome: either the invader peacefully coexists with the residents and resources are re-distributed; the invader is eliminated; or one or several of the resident species are removed in a uniquely defined extinction cascade. At the end of either of these processes the resulting food web relaxes to a globally stable (and feasible) steady state. We break down the essence of our theory in the conceptual “invasion extinction model” (IEM), which allows us to analytically compute the persistence time and the extinction size distribution.

    [1] Haerter, Jan O., Namiko Mitarai, and Kim Sneppen. "Theory of invasion extinction dynamics in minimal food webs." Physical Review E 97.2 (2018): 022404.
    [2] Haerter, Jan O., Namiko Mitarai, and Kim Sneppen. "Food web assembly rules for generalized Lotka-Volterra equations." PLoS computational biology 12.2 (2016): e1004727.
    [3]Haerter, Jan O., Namiko Mitarai, and Kim Sneppen. "Existence and construction of large stable food webs." Physical Review E 96.3 (2017): 032406.

東京大学東京大学 大学院総合文化研究科生物普遍性研究機構