Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2009
Publication Date: 11/19/2009
Citation: Gillespie, R., Smiley, P.C., King, K.W., Huang, C. 2009. Ecological Assessments of Fish Communities in Drainage Ditches of Two Midwest Watersheds in Support of the Conservation Effects Assessment. Society of Environmental Toxicology and Chemistry Abstracts. p. 179. Interpretive Summary:
Technical Abstract: The Conservation Effects Assessment Project (CEAP) began in 2004 with the objective of quantifying the environmental benefits of conservation practices implemented through USDA Farm Bill programs. The goal of the project described here is to evaluate the influence of conservation practices on agricultural drainage ditches in the Cedar Creek and Upper Big Walnut Creek watersheds that comprise 1416 km2 of land dominated by agricultural land use in Indiana and Ohio. These study areas currently serve as benchmark research sites in support of CEAP. Riparian habitat characteristics, fishes, macroinvertebrates, water chemistry, and instream habitat have been assessed annually at 20 sites since 2005. Our results suggest that freshwater fishes are an integral ecological component of agricultural drainage ditches in North America. We have documented 24 species of fish from 9,267 captures in three ditch systems in the Cedar Creek watershed and 25 fish species from 15,216 captures in seven ditches within the Upper Big Walnut Creek watershed. Our data suggest that management practices that alter water depth, water velocity, wet width, and substrate types will have a greater effect on fish communities than those practices that do not. These results do not exclude the probable significant roles of riparian habitat and negative effects of exposure to agrichemicals in affecting the health of fish communities in agricultural ditches. Concentrations of agricultural contaminants in ditches are more likely to cause chronic toxicity than acute toxicity. Overall, the risk of significant toxicity to fishes from agrichemicals appears to be low. However, chronic, sublethal responses may produce significant "ecological mortality" in agricultural drainage ditches and higher order streams. Understanding the relative influence of habitat and agrichemicals on fish communities will be useful for implementation of relevant management practices. Our results suggest that a watershed approach that manages ditches as a multiple use.