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Simulating stream network and water quality effects using fish assemblage models
Citation:
Ebersole, Joe, M. Snyder, B. Rashleigh, A. Brookes, J. Massie, G. Boxall, AND B. Waller. Simulating stream network and water quality effects using fish assemblage models. American Fisheries Society Annual Meeting, Atlantic City, NJ, August 19 - 23, 2018.
Impact/Purpose:
Fish communities in river networks provide significant ecosystem services that will likely decline under future land use, human water demand, and climate variability. We developed a model that simulates the consequences to multiple populations of one or more fish species from multiple stressors across a river network. The model is spatially-explicit and age-structured, with three components: habitat suitability; population dynamics, including species interactions; and movement across a spatial network. We apply the model to a fish assemblage in the Willamette River basin of Oregon, a region where human population and water demand are expected to grow substantially over the next 50 years. Although this model is simple, it can form the basis of fisheries assessments and may be incorporated into an integrated modeling system for watershed management and prediction.
Description:
We describe a modeling approach for simulating assemblages of fish in riverine landscapes. The approach allows users to simulate river networks within which fish populations reproduce, move, and survive in response to both environmental drivers and assemblage interactions. We apply the model to a fish assemblage in the Willamette River basin of Oregon, a region where human population and water demand are expected to grow substantially over the next 50 years. Model results reveal predictable fish population responses to changes in environmental factors such as streamflow and temperature, but also reveal unanticipated patterns associated with movement and biotic interactions. The approach provides a heuristic tool for identifying critical data gaps in our understanding of watershed-scale fish-habitat relationships, particularly as these may be influenced by species behaviors and interactions. Initial results provide testable hypotheses regarding species distributions and projected fish population responses to environmental change, water consumption, species invasions, and landuse effects on water temperature.