This dissertation project is about determining how various cattle and bison grazing practices influence sediment pollution and transport in grassland streams. Although grazing is a common land use practice, little is known about how different grazing practices affect sediment dynamics in the streams that drain these lands. Different species of grazing animals may produce significantly different sediment inputs to streams due to species-specific physiological and behavioral differences (e.g. wallowing, water demand, heat tolerance, vegetation preference). The researchers expect to find that grazed watersheds will have significantly higher sediment loads and higher frequencies and magnitudes of stream-bed sediment transport events because of increased hillslope erosion and stream-bed disturbance from trampling. Cattle grazed watersheds are predicted to have higher sediment loads than bison grazed watersheds because the behavioral habits of cattle are likely to produce more direct impacts and disturbances to channels. This project will advance the understanding of how species-specific impacts are driven by physiological and behavioral differences and contribute to a growing body of literature on biological engineering of landforms, or bio-geomorphology.
Sediment is one of the major pollutants impacting streams in the United States. High sediment loads have led to reservoir filling throughout North America and the world and are implicated as a major source of oxygen depletion in coastal systems. In the Great Plains region of North America, increased runoff and hillslope erosion rates have led to decreased water quality and decreased the social and economic value of freshwaters. Results of this project will help to inform conservation, restoration, and management practices of grassland streams. In particular, the results could serve as the basis for revised grazing best management practices to address water quality issues within the region. The results will be presented at national and local science and policy-oriented academic conferences, presented to state and regional agencies charged with grazing land management, and published in peer-reviewed scientific and management oriented journals. As a doctoral Dissertation Research Improvement award, this project will provide support to enable a promising scholar. It will also provide training for a number of other students including several from underrepresented groups including minorities, women, and military veterans.
