Identifying Vulnerabilities of Riverine Habitat and Fishes to Climate Change: Flow

Aquatic ecosystems in the Great Lakes region are vulnerable to climate changes because of the thermal gradient aquatic habitats and associated diverse biological communities, as well as climatic effects of the Great Lakes. Projections of climate change indicate warmer and wetter trends and potential hydrologic alteration, which can have profound effects on aquatic ecosystems by altering instream habitat and in turn changes in fish species distribution and community composition. This study integrates current predicted fish habitat conditions with downscaled (regional) climate predictions under different change scenarios to identify vulnerabilities of Great Lakes river systems to climate change, including likely shifts in stream flow. Landscape and climate-driven multiple regression models of present stream flow were re-applied with input from 26 climate models to project changes in each stream of the US Great Lakes Basin. Preliminary results indicate that there is a 50% chance (half of models agree) that mean annual flows will be reduced in 10%-20% of streams that presently have the lowest flows (<0.025 m³/s). There is also a 46% chance that mean annual flows in 10%-20% of streams presently in the two highest flow classes (>0.1 m³/s) will experience increased flows. These predictions are being linked to fish models.