Scholarly Commons

How Will Climate Change Impact Local Streams

Air temperatures are expected to increase 4 degrees Celsius over the next 50 years as a result of global climate change. As temperatures rise, the range of habitats will shift along the latitudinal gradients, potentially causing local species decline. This is especially true for less mobile species that are limited in their ability to disperse and colonize new habitats, for example specific fish species. Warmer temperatures will increasingly favor species with a higher thermal tolerance, including nonnative species. As they colonize new habitats, they are predicted to increase in population size and distribution, which could impact native species. Brook Trout (Salvelinus fontinalis) populations are native to headwater streams in the Appalachians of North America. This species is of high conservation need, with threats including stream temperature rise and competition with nonnative species, particularly Brown trout (Salmo trutta). Because Brown Trout have a have a higher thermal tolerance than Brook Trout, future competition is expected to decrease Brook Trout population sizes. Using an experimental stream system we evaluated the effects of Brown Trout on Brook Trout behavior, habitat use, and growth rates at three temperatures within the upper, lower, and intermediate thresholds for brook trout.