Fishes of Champaign County, Illinois: as affected by 120 years of stream changes

Abstract

With data spanning over 120 years, the Fishes of Champaign County is a comprehensive, long-term investigation into the changing fish communities of east-central Illinois. Surveys first occurred in Champaign County in the late 1880s (40 sites), with subsequent surveys in 1928–1929 (125 sites), 1959–1960 (143 sites), and 1987–1988 (141 sites). Between 2012 and 2015, we resampled 122 sites across Champaign County. The combined data from these five surveys have produced a unique perspective into not only the fish communities of the region, but also insight into in-stream habitat changes during the past 120 years. After a period of degradation, fish communities appear to be improving throughout the county, demonstrated by the return of two state-threatened species that had not been recorded since 1928. Our analysis of in-stream habitat indicates a general trend away from small streams of various substrate types toward wider, deeper streams with a more uniform substrate. Fish community data support the results, indicating a shift from typical headwater species to those species that frequent deeper streams with more stable flows. Long-term surveys such as this are rare, and the data and analyses of these surveys can provide managers with valuable information to further restoration efforts using a historical perspective.