title: Food webs obscure the strength of plant diversity effects on primary productivity.
abstract: Plant diversity experiments generally find that increased diversity causes increased productivity; however, primary productivity is typically measured in the presence of a diverse food web, including pathogens, mutualists and herbivores. If food web impacts on productivity vary with plant diversity, as predicted by both theoretical and empirical studies, estimates of the effect of plant diversity on productivity may be biased. We experimentally removed arthropods, foliar fungi and soil fungi from the longest-running plant diversity experiment. We found that fungi and arthropods removed a constant, large proportion of biomass leading to a greater reduction of total biomass in high diversity plots. As a result, the effect of diversity on measured plant productivity was much higher in the absence of fungi and arthropods. Thus, diversity increases productivity more than reported in previous studies that did not control for the effects of heterotrophic consumption.
authors.affiliation: Departments of Ecology, Evolution, and Behavior, University of MN, St. Paul, MN, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Seabloom
authors.affiliation: Department of Plant Pathology, University of MN, St. Paul, MN, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: Kinkel
authors.affiliation: Departments of Ecology, Evolution, and Behavior, University of MN, St. Paul, MN, USA.
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Borer
authors.affiliation: Departments of Ecology, Evolution, and Behavior, University of MN, St. Paul, MN, USA.|Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584, CH, The Netherlands.
authors.forename: Yann
authors.initials: Y
authors.lastname: Hautier
authors.affiliation: Department of Forest Resources, University of MN, St. Paul, MN, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Montgomery
authors.affiliation: Departments of Ecology, Evolution, and Behavior, University of MN, St. Paul, MN, USA.
authors.forename: David
authors.initials: D
authors.lastname: Tilman
mesh_terms: D000818:Animals; D001181:Arthropods / Q000502:physiology*; D044822:Biodiversity; D020387:Food Chain; D005658:Fungi / Q000502:physiology*; D060434:Herbivory; D018521:Plant Physiological Phenomena; D010944:Plants / Q000382:microbiology
keywords: Biodiversity; community ecology; dilution effect; ecosystem ecology; pathogens