QUANTIFYING INTERANNUAL AND AMONG-STREAM VARIATION IN ORGANIC-MATTER DECOMPOSITION RATES TO EVALUATE STREAM ‘HEALTH’
Human activities increasingly compromise the ecological integrity or ‘health’ of streams. Organic-matter decomposition has been proposed as process-based tool for evaluating the impact of these activities. A key first step toward developing this tool is to quantify spatial and temporal variability in decomposition among reference streams. Using the cotton-strip assay, we evaluated the among-stream and interannual variation of organic-matter decomposition in 26 reference streams in the Upper Peninsula of Michigan (USA) during the same month for 8 years (~208 stream-years). We observed significant variation in decomposition rates among streams and among years. Spatial and temporal factors explained a similar amount of variation on a per-stream and per-year basis. Subsequent analysis of temperature-corrected decomposition rates, to address the role of temperature, did not reduce much of this variation among streams and years, suggesting that other factors are important. Further analyses of impacts of in-stream characteristics will be performed to account for this variation in order to create a decomposition-based tool that is more sensitive to human impacts.
Mark Isken (Co-Presenter/Co-Author), Dept. of Decision and Information Sciences, School of Business Administration, Oakland University, firstname.lastname@example.org;
Scott Tiegs (Co-Presenter/Co-Author), Dept. of Biological Sciences, Oakland University, email@example.com;
Emily Messick (Primary Presenter/Author), Dept. of Biological Sciences, Oakland University, firstname.lastname@example.org;