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SFS Annual Meeting

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ZOOBENTHIC ASSEMBLAGE CONDITION INDEX FOR LAKE ERIE

We derived and calibrated a Lake Erie multivariate zoobenthic index by sampling across the full range of an environmental stress gradient, ordinating response variables against the gradient and identifying the changing range of variability (quantiles) in the response variables. A composite stressor gradient was created by combining consensus-derived Great Lakes Environmental Assessment and Mapping (GLEAM) stress layers likely to influence zoobenthos. We then examined variation in zoobenthic composition in samples collected in 2004, 2010 and 2015/16 through L. Erie Comprehensive Collaborative Studies (ECCS; 125-294 stratified-randomly selected stations). Sites situated in the lowest stress quintile were designated “Reference” locations. Cluster analysis of these sites identified 3 biological groups, spatially distinguishable according to basin, depth and substrate type. Habitat-specific benthic composite indices were derived by relating changing community composition to stress gradient scores. Hexagenia mayflies, gammarid amphipods, and oligochaete species/chironomid genera characterized reference sites of shallow-soft (western basin), shallow-hard, and deep-soft habitat locations respectively. Stress thresholds were identified by piecewise regression. Post hoc classification accuracy varied by habitat type, ranging from 40-70%.

Jan Ciborowski (Primary Presenter/Author), Department of Biological Sciences, University of Windsor, cibor@uwindsor.ca;


David Barton (Co-Presenter/Co-Author), University of Waterloo, drbarton@uwaterloo.ca;


Valerie Brady (Co-Presenter/Co-Author), Natural Resources Research Institute, University Minnesota Duluth, vbrady@d.umn.edu;


Meijun Cai (Co-Presenter/Co-Author), University of Minnesota Duluth, Natural Resources Research Institute, mcai@d.umn.edu;


Katya Kovalenko (Co-Presenter/Co-Author), Natural Resources Research Institute, Univ. Minnesota Duluth, philarctus@gmail.com;


Kenneth Krieger (Co-Presenter/Co-Author), Heidelberg University, kkrieger@heidelberg.edu;


Sigrid Smith (Co-Presenter/Co-Author), University of Michigan, sdpsmith@umich.edu;


Jabed Tomal (Co-Presenter/Co-Author), University of Toronto Scarborough, jtomal@utsc.utoronto.ca;


David Allan (Co-Presenter/Co-Author), University of Michigan, dallan@umich.edu;


Lucinda Johnson (Co-Presenter/Co-Author), Natural Resources Research Institute, University of Minnesota Duluth, ljohnson@d.umn.edu;