Submitted to: Journal of Soil and Water Conservation
Publication Type: Other
Publication Acceptance Date: 4/23/2008
Publication Date: 11/1/2008
Publication URL: http://hdl.handle.net/10113/22878
Citation: Smiley, P.C., Gillespie, R.B., King, K.W., Huang, C. 2008. Relative Contributions of Habitat and Water Quality to the Integrity of Fish Communities in Agricultural Drainage Ditches. Journal of Soil and Water Conservation. 63:218A-219A. Interpretive Summary: Management of agricultural drainage ditches focuses on removing water from agricultural fields without considering the potential impacts on water quality or the aquatic biota. There is a need to identify methods of incorporating environmental considerations into the management of these modified streams that are common within the midwestern United States. The limited understanding of the ecology of drainage ditches hinders the development of optimal management strategies. We determined the whether riparian habitat, instream habitat, or water chemistry influenced fish communities within ditches in Indiana and Ohio the most. Instream habitat had a greater influence on fish communities than riparian habitat or water chemistry. Our results provide information for state and federal agencies attempting to develop ditch management plans that are capable of meeting drainage and environmental quality guidelines. Specifically, our results suggest that conservation practices that alter the aquatic component of these modified ecosystems will have the greatest impact on fish communities. Thus, conservation practices, such as controlled drainage and ditch maintenance, may have a greater impact on fish communities than pesticide management and filter strips.
Technical Abstract: Management of agricultural drainage ditches focuses on removing water from agricultural fields and ignores the potential impacts of these hydrological and geomorphological modifications on the water quality and aquatic biota. There is a need to identify methods of incorporating environmental considerations into ditch management. Conservation practices were traditionally methods of managing soil and water resources for improving agricultural production, but now include methods to reduce the environmental impacts of agriculture. However, there is a limited understanding of the ecology of ditches and the ecological impacts of conservation practices on these modified lotic ecosystems has not been evaluated. Development of optimal management strategies for ditches will be hindered until a better understanding of the ecology within these ecosystems is achieved. Understanding the relationships between fish communities and physico-chemical factors within agricultural drainage ditches is a first step towards determining the potential impacts of conservation practices on these modified ecosystems. We conducted a preliminary analysis of two years of ecological data collected from ten drainage ditches in ARS CEAP watersheds in Indiana and Ohio to evaluate the relative importance of riparian habitat, instream habitat, and water chemistry in determining the structure of fish communities. We observed that instream habitat had a greater influence on fish communities than riparian habitat or water chemistry. Our results suggest that conservation practices that alter instream habitat will have the greatest impact on fish communities.