Physical, chemical, and biological responses to urbanization in the Fox and Des Plaines River basins of northeastern Illinois and southeastern Wisconsin

Abstract

VI 3-11. Graphs showing 3. Land cover in drainage basins of 45 stream sites sampled in northeastern Illinois and southeastern Wisconsin, 2000-01, ordered by percent urban land.........6 4. Scatterplots of selected variables along the urban gradient, percent watershed urban land, for 45 stream sites in northeastern Illinois and southeastern

Effects of Tributary Spatial Position, Urbanization, and Multiple Low‐Head Dams on Warmwater Fish Community Structure in a Midwestern Stream

“…Our study also corroborates the commonly found pattern that high proportions of urban land are associated with decreased fish species diversity. Almost all of our study sites were located in watersheds with more than 10% urban land use, a level known to be associated with a significant loss in fish species abundance and diversity, especially in this region of the U.S. (Ruhl 1995;Dreher 1997;Wang et al 2000;Fitzpatrick et al 2004;Harris et al 2005).…”

“…For example, there are limited riparian buffers along the Des Plaines River and associated tributaries in the urbanized areas of this system, and the loss of riparian buffers is known to have a significant negative impact on fish communities (Roth et al 1996;Wang et al 1997;Stewart et al 2001). Furthermore, increased urbanization within the Des Plaines River watershed is associated with decreased water and sediment quality as a result of increased point and nonpoint sources of phosphorus and nitrate; increased proportion of wastewater compounds, including detergents, insecticides, polycyclic aromatic hydrocarbons (PAHs), and flame retardants; elevated chloride concentrations; and increased sediment concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc (Harris et al 2005). Therefore, we think it very likely that the fish communities within the Des Plaines River watershed are responding to the reduction in water quality associated with increased urbanization in this watershed.…”

“…This suggests to us that as urbanization increases within these watersheds the resulting changes in fish communities take the form not of changes in species diversity but in changes from coolwater-specialist fish assemblages to warmwatergeneralist fish assemblages. The HT and MT sites overlap at about 40% to 50% urban land use, the levels at which transitions in community composition typically occur in the Des Plaines River (Harris et al 2005).…”