title: Predicting abundances of plants and pollinators using a simple compartmental mutualistic model.
abstract: Key gaps to be filled in population and community ecology are predicting the strength of species interactions and linking pattern with process to understand species coexistence and their relative abundances. In the case of mutualistic webs, like plant-pollinator networks, advances in understanding species abundances are currently limited, mainly owing to the lack of methodological tools to deal with the intrinsic complexity of mutualisms. Here, we propose an aggregation method leading to a simple compartmental mutualistic population model that captures both qualitatively and quantitatively the size-segregated populations observed in a Mediterranean community of nectar-producing plant species and nectar-searching animal species. We analyse the issue of optimal aggregation level and its connection with the trade-off between realism and overparametrization. We show that aggregation of both plants and pollinators into five size classes or compartments leads to a robust model with only two tunable parameters. Moreover, if, in each compartment, (i) the interaction coefficients fulfil the condition of weak mutualism and (ii) the mutualism is facultative for at least one party of the compartment, then the interactions between different compartments are sufficient to guarantee global stability of the equilibrium population.
authors.affiliation: Complex Systems Group, Institute of Physics, Facultad de Ciencias, Univ. de la República, 11400 Montevideo, Uruguay.
authors.forename: Hugo
authors.initials: H
authors.lastname: Fort
authors.affiliation: Physics Department, Boğaziçi University, Bebek 34342, Istanbul, Turkey mmungan@boun.edu.tr.
authors.forename: Muhittin
authors.initials: M
authors.lastname: Mungan
mesh_terms: D000818:Animals; D007313:Insecta / Q000502:physiology*; D019684:Magnoliopsida / Q000502:physiology*; D008954:Models, Biological; D054817:Pollination; D011156:Population Density; D013030:Spain; D013559:Symbiosis
keywords: Lotka–Volterra mutualism; aggregation; compartmental models; plant–pollinator communities; size constraints