Fish Habitat and Climate Change: A Coarse Scale National Assessment with Finer Scale Assessment of Midwestern Streams and Lakes
Affiliation: *Michigan State University, **University of Minnesota-Duluth
Documents & Resources
This webinar is Part 2 in a set of two presentations. Part 1 was held on Thursday, April 11.
The effects of climate change on fish habitat will be scale-and system-dependent. Our work demonstrates how climate change affects fish habitat nationwide, and stream flow, water temperature, and coldwater lakes in the Upper Midwest. Projected changes in fish habitat varied across ecoregions nationally. The future regional climate will likely alter hydrologic and thermal regimes suitable to the fish species in that region. We were able to integrate these regional differences by using a consistent assessment framework to show habitat changes across regions for the conterminous U.S. Midwestern stream temperatures generally increased but were heavily influenced by AOGCM used. Central Minnesota streams were predicted to cool from all three climate models. Although our models predict substantial decreases in coldwater trout habitat, larger changes were found for cool- and warm-transitional stream habitat. Average annual, spring peak, and fall low exceedence flows increased although magnitudes are difficult to quantify. Increasing air temperatures and longer open-water periods are projected to increase lake water temperatures in Minnesota, Wisconsin, and Michigan and reduce coldwater fish habitat. Lakes also impacted by watershed nutrient loading were projected to experience the greatest habitat loss, as hypolimnetic dissolved oxygen concentrations further limit coldwater habitat. These results show that the scale at which we assess climate change impacts may influence decisions made, and that the different attributes of lakes and stream require different approaches to determine climate and land use change effects on fish habitat.
Image Credit: J. Whittier