ENVIRONMENTAL AND SOURCE WATER QUALITY EFFECTS OF MANAGEMENT PRACTICES AND LAND USE ON POORLY DRAINED LAND
Location: Soil Drainage Research
Title: Implications of Fish-Habitat Relationships for Developing Conservation Plans for Channelized Headwater Streams in the Midwestern United States
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2008
Publication Date: September 3, 2008
Citation: Smiley, P.C., Gillespie, R.B., King, K.W., Huang, C. 2008. Implications of Fish-Habitat Relationships for Developing Conservation Plans for Channelized Headwater Streams in the Midwestern United States. Meeting Abstract.
Many headwater streams in the midwestern United States were channelized for agricultural drainage. Conservation practices are implemented to reduce nutrient and pesticide loadings within these altered streams. The impact of these practices is uncertain because the influence of water chemistry on stream communities is not well understood. We evaluated the relationships between water chemistry and fish communities within channelized headwater streams in Cedar Creek, Indiana and Upper Big Walnut Creek, Ohio. Measurements of water chemistry, hydrology, and fishes have been collected from 20 sites beginning in 2005. Backward selection multiple regression analyses indicated that fish communities were most often correlated with pH and dissolved oxygen and least frequently correlated with alachlor, metolachlor, and nitrate-nitrite. Observed relationships between water chemistry and fish communities were weak, but significant (P < 0.05). The strongest relationship (r2 = 0.44) occurred between percent insectivores and ammonia, soluble reactive phosphorus, total phosphorus, atrazine, water temperature, conductivity, and pH. The weakest relationship (r2 = 0.09) occurred between percent omnivores and dissolved oxygen. Backward selection multiple regression analyses also indicated that most water chemistry variables (8/13) were significantly (P < 0.05) correlated with water depth, velocity, or wet width. However, preliminary results found that including hydrology variables in the regression models did not alter the observed relationships between water chemistry and fish communities. Our results suggest physicochemical characteristics are more likely to have a greater impact on fish communities than nutrients or pesticides. Thus, conservation practices designed to reduce nutrient and pesticide loadings within channelized streams are unlikely to have a strong impact on fish communities within channelized headwater streams in the midwestern United States.