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Effects of stream predator richness on the prey community and ecosystem attributes.

Author:
  • Erika Nilsson
  • Karin Olsson
  • Anders Persson
  • Per Nyström
  • Gustav Svensson
  • Ulf Nilsson
Publishing year: 2008
Language: English
Pages: 641-651
Publication/Series: Oecologia
Volume: 157
Issue: 4
Document type: Journal article
Publisher: Springer

Abstract english

It is important to understand the role that different predators can have to be able to predict how changes in the predator assemblage may affect the prey community and ecosystem attributes. We tested the effects of different stream predators on macroinvertebrates and ecosystem attributes, in terms of benthic algal biomass and accumulation of detritus, in artificial stream channels. Predator richness was manipulated from zero to three predators, using two fish and one crayfish species, while density was kept equal (n = 6) in all treatments with predators. Predators differed in their foraging strategies (benthic vs. drift feeding fish and omnivorous crayfish) but had overlapping food preferences. We found effects of both predator species richness and identity, but the direction of effects differed depending on the response variable. While there was no effect on macroinvertebrate biomass, diversity of predatory macroinvertebrates decreased with increasing predator species richness, which suggests complementarity between predators for this functional feeding group. Moreover, the accumulation of detritus was affected by both predator species richness and predator identity. Increasing predator species richness decreased detritus accumulation and presence of the benthic fish resulted in the lowest amounts of detritus. Predator identity (the benthic fish), but not predator species richness had a positive effect on benthic algal biomass. Furthermore, the results indicate indirect negative effects between the two ecosystem attributes, with a negative correlation between the amount of detritus and algal biomass. Hence, interactions between different predators directly affected stream community structure, while predator identity had the strongest impact on ecosystem attributes.

Keywords

  • Ecology
  • Detritus
  • Open system
  • Periphyton biomass
  • Prey diversity

Other

Published
  • ISSN: 1432-1939
Anders Persson
E-mail: anders [dot] persson [at] biol [dot] lu [dot] se

Senior lecturer

Aquatic ecology

+46 46 222 83 67

E-D113

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