Date of Award
Master of Science
Natural Resource Ecology and Management
Janette R. Thompson
Timothy W. Stewart
In spite of increasingly stringent water policy and years of stream ecology research, urban and agricultural land uses continue to degrade stream ecosystems across the United States. This is due in part to incomplete scientific understanding of land use impacts on streams. I quantified relationships among land use, in-stream environmental metrics, and invertebrate metrics in streams of central Iowa to provide insight into differential impacts of agriculture and urbanization on stream condition, and to identify potential mechanisms of land use effects on stream condition. Results suggest that even moderate levels of urban land use can have greater adverse effects on headwater stream ecosystems than intensive agriculture. However, even in highly degraded streams, invertebrate assemblages and related ecosystem functions likely benefit from practices that maintain or increase abundance of coarse substrate, particulate organic matter, and plants.
In urban areas, continuing degradation of stream ecosystems also results from difficulty in fully integrating human and non-human factors into research of stream ecosystems, and from inadequate knowledge of effectiveness of stream restoration practices. We addressed these challenges in a project that integrated public participation, urban stream restoration, and ecological research. We facilitated mutual learning through public participation in the design and implementation of an urban riparian buffer, a process that was informed by ecological research. Evaluations of learning revealed that participants' knowledge about urban water quality issues and stormwater management practices increased, and their perceptions about the importance of stream ecosystem functions changed. Infiltration tests and in-stream monitoring provided early evidence of buffer effectiveness in absorption of runoff and pollutants from surrounding surfaces. Elements essential to the success of this project included an opportunity for dialog focused on a specific natural feature, sustained interaction between participants and researchers, opportunities for hands-on participation, and flexibility in restoration practice installation. Integrated research and restoration projects like this one can overcome many of the obstacles that hinder efforts to reduce human impacts on streams.
Cassie J. Herringshaw
Herringshaw, Cassie J., "Stream ecosystems in human-dominated landscapes: investigating land use impacts and integrating public participation, restoration, and research" (2009). Graduate Theses and Dissertations. 10816.