title: Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.
abstract: Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions.
authors.affiliation: Laboratory of Environmental Toxicology and Applied Ecology, Ghent University, Jozef Plateaustraat 22, 9000 Ghent, Belgium.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Baert
authors.affiliation: Laboratory of Environmental Toxicology and Applied Ecology, Ghent University, Jozef Plateaustraat 22, 9000 Ghent, Belgium.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Janssen
authors.affiliation: Laboratory of Protistology and Aquatic Ecology, Ghent University, Krijgslaan 281-S8, 9000 Ghent, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Sabbe
authors.affiliation: Research Unit of Environmental and Evolutionary Biology, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: De Laender
mesh_terms: D044822:Biodiversity; D017753:Ecosystem; D008954:Models, Biological; D013312:Stress, Physiological