SS3.07 Headwater Ecosystems in Forested Landscapes and Beyond
Date: Wednesday, June 12, 2002
Time: 10:30:00 AM
Location: View Royal
 
RichardsonJS, Univ. of British Columbia, Vancouver, Canada, jrichard@interchg.ubc.ca
Kiffney, P, M, National Marine Fisheries Service, Seattle, USA, Peter.Kiffney@noaa.gov
Feller, M, C, Univ. of British Columbia, Vancouver, Canada, feller@interchg.ubc.ca
 
AN EXPERIMENTAL STUDY OF THE EFFECTS OF RIPARIAN MANAGEMENT ON COMMUNITIES OF SMALL STREAMS: ESTABLISHING CAUSAL MECHANISMS
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Headwater systems (small, low order streams) are a common feature of most landscapes. Despite receiving little attention relative to fish-bearing reaches, these streams support a diverse assemblage of invertebrates and other organisms, and contribute in a large way to downstream processes through storage and export of organic matter and other substances. We performed a BACI experiment to evaluate the effectiveness of riparian reserves using 13 small streams assigned to controls or one of three treatments: 30 m reserves, 10 m reserves, and clearcuts. We measured aspects of the food web (invertebrate numbers, biomass, richness, algal productivity), organic carbon dynamics, water quality, and riparian communities . Even with 30 m reserves there were five-fold increases in the amount of algal biomass, and shifts to filamentous forms and enhanced fine sediment trapping as riparian protection was reduced. Invertebrate communities exhibit shifts to more generalist taxa, such as Baetis, Ameletus, and chironomids as the degree of riparian reserve decreased. Cumulative effects downstream show reduced organic matter supply due to loss of inputs and higher export rates from the headwaters.