Predicting Coldwater Fish Habitat in Lakes of the Glacial Lakes Region under Changing Land Use and Climate Regimes (Local Assessment)

The goal of the glacial lakes regional study was to predict the impacts of climate and land use change on coldwater fish habitat in the glacial lakes region, which covers most of Minnesota, Wisconsin, and Michigan. The study includes both top-level, regional analyses and more detailed case studies of individual lakes. The goal of this project was to provide (1) projections of land use and climate change impacts on the trophic status of Midwestern coldwater glacial lakes, (2) projections of land use and climate change impacts on the regional distribution of coldwater lake oxythermal habitat, and (3) guidance on the types of coldwater lakes in which locations will be the most or least vulnerable to land use and climate change. To do so, methods were developed for conducting regional analyses of large numbers of coldwater lakes, including models for watershed nutrient loading and lake response models. Retrospective analyses were also conducted on trends in ice-out, water temperature, and fish assemblages in Minnesota’s lakes, based on historic data. These models can then be used to help inform management decisions regarding the protection and restoration of lakes and their watersheds with respect to maintenance of cold water refugia under future climate and land use scenarios. The goal of this project was to produce a Watershed Nutrient Loading Model and a Lake Response Model.The former is comprised of regional models for nutrient loading to coldwater lakes that will enable prediction of the changes in lake nutrient loading and concentration in response to changes in land use and climate. Meanwhile, the latter is a deterministic lake model (MINLAKE) calibrated for current conditions for a set of coldwater Cisco lakes in Minnesota. The calibrated models can then be used to predict changes in habitat (temperature and dissolved oxygen profiles) in response to climate change for several global climate change scenarios. The final project objective was to develop an online web application to aid in visualization, inter-model comparison, and data dissemination of dynamically downscaled climate simulations based on Intergovernmental Panel on Climate Change emission scenarios.