COS 139-5
Synthesizing and modeling interactions among environmental stressors in the Laurentian Great Lakes

Friday, August 14, 2015: 9:20 AM
321, Baltimore Convention Center
Sigrid D.P. Smith, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI
David B. Bunnell, USGS Great Lakes Science Center, Ann Arbor, MI
Allen Burton, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI
Jan J.H. Ciborowski, Biological Sciences, University of Windsor, Windsor, ON, Canada
Alisha Davidson, Department of Biological Sciences, Wayne State University
Caitlin Dickinson, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI
Peter Esselman, Great Lakes Science Center, USGS
Mary Anne Evans, Great Lakes Science Center, USGS
Donna R. Kashian, Department of Biological Sciences, Wayne State University, Detroit, MI
Nathan Manning, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI
Peter B. McIntyre, Center for Limnology, University of Wisconsin, Madison, WI
Thomas Nalepa, University of Michigan Water Center, University of Michigan
Alicia Pérez-Fuentetaja, Biology, SUNY – Buffalo State
Alan D. Steinman, Annis Water Resources Institute, Grand Valley State University, Muskegon, MI
Donald Uzarski, Biology, Central Michigan University
David Allan, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI
Background/Question/Methods

Many environmental stressors can occur simultaneously in an ecosystem. However, their cumulative effects on ecosystem condition are difficult to predict, since stressors can be amplified or mitigated when they co-occur. We synthesized the incidence of stressor interactions in the Laurentian Great Lakes with a systematic literature review and structured expert elicitation. In the review, we searched pairs of stressors and interaction-related keywords with location, augmenting our results with recommendations from experts. The elicitation included discussion in focus groups and a follow-up survey. To explore the effects of stressor interactions on ecosystem condition holistically, we modified a spatial model of cumulative impact that additively combined the spatial distributions of 34 stressors.

Results/Conclusions

In the literature, we found that authors discussed synergies in the majority of relevant studies, such as interactions of invasive mussels and climate change with other stressors, but full quantification of individual and joint effects were rare. In the elicitation, researchers particularly implicated nutrient loading in interactions, expecting synergies with invasive mussels, hypoxia, wetland loss, and climate change. Considering the effects of such interactions, conservative scenarios with our cumulative impact model showed that antagonisms strongly affected maps of relative stress. Currently, we are using conceptual models to explore key interactions and identify knowledge gaps, and we are incorporating the specific interactions from the review and elicitation into a new best-estimate map of cumulative stress to inform management and restoration efforts.