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Monday, May 26, 2008 - 11:15 AM
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Scratching the surface: Cumulative effects of headwater enclosures on fish and BMI assemblages and water chemistry in stream agro-ecosystems
Katie L. Stammler, Biology, University of Western Ontario, 1151 Richmond Street, Suite 2, London, ON N6A 5B8, Canada and R.C. Bailey, Department of Biology, The University of Western Ontario, London, ON N6A 5B7, Canada.
In intensively farmed areas, headwater streams are often enclosed to increase the efficiency of farming and reduce soil erosion. Enclosures involve burying open first or second order streams and replacing them with drain tiles installed below the soil surface. We wish to relate the degree of enclosedness of headwater streams in cultivated fields to the downstream ecosystem’s structure and function in the Ausable River basin (ARB) in southwestern Ontario. Ten watercourses in the ARB with varying degrees of upstream enclosedness, but similar in natural variation, were selected for this study. Fish and benthic macroinvertebrate assemblages were characterized using standardized sampling protocols in July and November 2007. Water samples were collected monthly from July – November 2007 and analyzed for ammonia, nitrate and major ions (P3-, Ca2+, Mg2+, K+, Na+). Data from this field sampling enable us to test the hypothesis that enclosedness affects, among other ecosystem attributes, the diversity and composition of the downstream fish and benthic invertebrate community. Our findings will aid managers in Ontario in setting scientifically defensible regulations regarding stream enclosures and will significantly further our knowledge of the importance of headwater streams to downstream ecosystems.
Web Page: stream ecology, bioassessment, agriculture
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See more of The Nabs 56th Annual Meeting (25-28 May, 2008)
See more of Contributed Sessions
See more of The Nabs 56th Annual Meeting (25-28 May, 2008)