Aquatic Sciences Meeting, Albuquerque 2001

CS34 Trophic Dynamics

Date: Friday, February 16, 2001, Time: 11:00:00 AM

Location: Mesilla

Taylor, B, W, Rocky Mountain Biological Laboratory, Crested Butte, Colorado 81224 and University of Wyoming, Laramie, USA, btaylor@uwyo.edu

LARGE-SCALE INVERTEBRATE MANIPULATIONS IN STREAM ECOSYSTEMS: INVERTEBRATE REMOVAL, ALGAL RESPONSE, AND OPPORTUNITIES FOR INNOVATION

The ability to perform large-scale experimental manipulations is critical for expanding our knowledge of community and ecosystem level processes. Experimental manipulations in aquatic ecosystems at large spatial scales present logistical and analytical challenges that require creative experimental approaches. Here, I describe a new approach for performing large-scale manipulations of invertebrate communities in streams using a modified electroshocking technique. Electroshocking enables effective and non-destructive removal of invertebrates. This technique reduces invertebrate abundance and biomass by an order of magnitude at a large spatial scale (50 meter reach). Although mobile invertebrates recolonized the manipulated area rapidly, repeated electroshocking every two days enabled the density reduction to be maintained. The ability to reduce herbivorous insects by an order of magnitude and to maintain the manipulation released algae from grazing, resulting in an increase in algal biomass. This experimental manipulation of consumers in an open system provides a powerful method to answer questions in the field, at a large spatial scale, with more realism than streamside mesocosms, and less logistical problems than whole-ecosystem experiments.

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Aquatic Sciences Meeting, Albuquerque 2001

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