Trophic tangles through time? Opposing direct and indirect effects of an invasive omnivore on stream ecosystem processes.

ABSTRACT: Omnivores can impact ecosystems via opposing direct or indirect effects. For example, omnivores that feed on herbivores and plants could either increase plant biomass due to the removal of herbivores or decrease plant biomass due to direct consumption. Thus, empirical quantification of the relative importance of direct and indirect impacts of omnivores is needed, especially the impacts of invasive omnivores. Here we investigated how an invasive omnivore (signal crayfish, Pacifastacus leniusculus) impacts stream ecosystems. First, we performed a large-scale experiment to examine the short-term (three month) direct and indirect impacts of crayfish on a stream food web. Second, we performed a comparative study of un-invaded areas and areas invaded 90 years ago to examine whether patterns from

SUBMITTER: Moore JW 

PROVIDER: S-EPMC3507779 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature