title: Daphnia inhibits the emergence of spatial pattern in a simple consumer-resource system.
abstract: Spatial self-organization can occur in many ecosystems with important effects on food web dynamics and the maintenance of biodiversity. The consumer-resource interaction is known to generate spatial patterning, but only a few empirical studies have investigated the effect of the consumer on resource distribution. Here we report results from a large aquatic mesocosm experiment used to investigate the effect of the consumer Daphnia magna on the distribution of its resource, the green algae Chlorella vulgaris. We maintained large tanks with capacity for 26 ,000 L with either algae or both algae and Daphnia in different temperature conditions. We found that the presence of D. magna inhibited spatial structure in algal distribution that arose as a consequence of increasing temperature. We conjecture that this homogenization effect might be caused by a combination of high mobility combined with high rates of algal consumption by Daphnia. Our study emphasizes the importance of both local constraints on growth and behavioral responses in either promoting or suppressing spatial self-organization in natural populations.
authors.affiliation: Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Gustavo S
authors.initials: GS
authors.lastname: Betini
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.
authors.forename: Tal
authors.initials: T
authors.lastname: Avgar
authors.affiliation: Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: McCann
authors.affiliation: Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
authors.forename: John M
authors.initials: JM
authors.lastname: Fryxell
mesh_terms: D000818:Animals; D048408:Chlorella vulgaris; D000460:Chlorophyta; D003621:Daphnia / Q000502:physiology*; D017753:Ecosystem; D020387:Food Chain
keywords: 
  Chlorella vulgaris
  ; aquatic mesocosmos; freshwater systems; green algae; movement; predator-prey system; scale-dependent feedback; self-organization; spatial variation