Gounand, I., Kefi, S.,Mouquet, N., Gravel, D. (2016).

Theoretical Ecology, doi:10.1007/s12080-016-0299-7

Key message : In this study, we build on classical consumer–resource theory to analyze the implications of the assembly process on trait selection in food webs. Using bioenergetic models, we investigate the selective pressure on body mass and conversion efficiency and its dependence on trophic structure and temperature. We find that the selection exerted by exploitative competition is highly sensitive to how the energy fluxes are modeled. However, the addition of a trophic level consistently selects for smaller body masses of primary producers. An increase in temperature triggers important cascading changes in food webs via a reduction of producer biomass, which is detrimental to herbivore persistence. This affects the structure of trait distributions, which in turn strengthens the exploitative competition and the selective pressure on traits.

Variation of producer traits along food web assembly for each of the four models considered. Symbols show the average value of a trait over all the species in a community at a given assembly step (one simulation). a Yellow diamonds and purple triangles refer to uptake and mortality rates, respectively; b–d Squares refer to the logarithm of specific body mass M; e–h circles refer to the conversion efficiency. Solid lines indicate the average values over 50 simulated assemblies.

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OTHER TOPICS: Aesthetics of Biodiversity, Biodiversity & Ecosystem Functioning, Biogeography, Macroecology & Ecophylogenetics, Experimental Evolution, Functional Biogeography, Functional Rarity, Metacommunities, Metaecosystems, Reviews and Synthesis, Trophic Biogeography & Metaweb