ARS | Publication request: Influence of watershed-scale pesticide management on channelized agricultural headwater streams

Submitted to: Society for Ecological Restoration Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 26, 2011
Publication Date: August 21, 2011
Citation: Smiley, P.C., King, K.W., Gillespie, R., Fausey, N.R. 2011. Influence of watershed-scale pesticide management on channelized agricultural headwater streams. Society for Ecological Restoration Abstracts. p. 185.

Technical Abstract: Channelized agricultural headwater streams are streams that have been created or modified for agricultural drainage. Elevated pesticide concentrations frequently occur within these modified streams and represent a threat to their ecological integrity. Pesticide management (i.e., use of alternative herbicides, crop rotations, reduced herbicide use) is intended to reduce excess pesticide concentrations within agricultural streams. Yet, the influence of pesticide management on channelized agricultural headwater streams has not been empirically evaluated. We used a reverse before-after-control impact design to evaluate the influence of watershed-scale pesticide management targeting atrazine on the water chemistry and stream communities within channelized agricultural headwater streams in central Ohio. Water samples for nutrient and pesticide measurements and stream communities were collected during the spring and summer over a five year period from a treatment stream that initially received pesticide management (2006, 2007) and then did not in the last three years of the study (2008-2010). We also sampled water chemistry and stream communities within a control stream that did not receive pesticide management. Our initial results found that pesticide management reduced the frequency of atrazine occurrence and the total number of pesticides, but it did not reduce the mean concentration of atrazine or deethylatrazine. We also observed that pesticide management did not influence fish species richness, abundance, evenness, or the percentage of headwater fish species captured. Our preliminary results suggest that watershed-scale pesticide management has the potential to contribute to watershed restoration projects through its water chemistry impacts, but its effects on stream community structure appear limited.