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Presented at the NABS Annual meeting, Anchorage, Alaska, 2006
in Bioassessment
Cumulative ecological effects of agriculture stressors on stream benthic ecosystems
E.A. Luiker1, J.M. Culp1, A. Alexander2, K.S. Heard2, and R.A. Curry2.1National Water Research Institute, Environment Canada, Department of Biology, University of New Brunswick, Fredericton, NB, E3B 6E1, 2Canadian Rivers Institute, Department of Biology, University of New Brunswick, Fredericton, NB, E3B 6E1
Field run-off in areas of agricultural activity can carry nutrients and pesticides to adjacent streams. The fate of these stressors on the benthic aquatic environment is various and the effects potentially cumulative. Determining cause and effect relationships from multiple agricultural stressors requires an approach that can identify the effects of individual stressors on their own and in combination. To aid in the investigation of cause of these stressors on the aquatic benthic community, we used a weight of evidence approach combining the sediment quality triad (proposed by Chapman 1990, which includes “chemistry to measure contamination, bioassay to measure toxicity, and in situ biological assessment”), and the novel nutrient enrichment triad (which includes chemistry to measure nutrient concentrations, periphyton chl a measurements to estimate productivity, and studies to determine nutrient limitation). Effects of pesticide exposure and nutrient enrichment on the benthic community of two brooks (Black, Dead) in New Brunswick, Canada were evaluated using this integrated response method. These second order watersheds drain an area of intensive agriculture activity (largely potato production). Results indicate that individual and cumulative stressor effects can be estimated using this assessment approach.
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