Relationships Among Land Use, Geomorphology, Local Habitat and Aquatic Macroinvertebrate Assemblages in Agricultural Headwater Stream Systems

Download or read book Relationships Among Land Use, Geomorphology, Local Habitat and Aquatic Macroinvertebrate Assemblages in Agricultural Headwater Stream Systems written by Elizabeth Ellen Risley and published by . This book was released on 2006 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In-stream habitat structure and water chemistry have significant influence on the structure and composition of stream macroinvertebrate assemblages. Habitat at this local scale can be significantly affected by the geomorphology of a stream or region. Both in-stream habitat and geomorphology are, in turn, influenced by other factors operating at the landscape scale (e.g., land use, connectivity of habitat patches, etc.). It is unclear which of these three scales of habitat has the greatest influence over lotic assemblage structure. Anthropogenic disturbance to a stream ecosystem can occur at all three scales of habitat, and is particularly common in predominantly agricultural systems. The Sugar Creek watershed in northeastern Ohio represents several different types of anthropogenic disturbance, including dairy farming, crop production, urbanization, and industrialization. The South and Middle Forks of the Sugar Creek watershed, dominated by agriculture and a mix of agriculture and industry, respectively, were sampled in early summer 2005 for habitat and macroinvertebrates. Richness, evenness, diversity, familylevel biotic index, percent Diptera Chironomidae, and the number of macroinvertebrates were all similar across the drainages. The percent Ephemeroptera, Plecoptera, and Trichoptera was significantly larger in the Middle Fork than in the South Fork. There were no significant differences in habitat or macroinvertebrate assemblages between the two drainages overall. In-stream habitat structure and water chemistry explained 58.8% of the variation between sites among macroinvertebrate taxa. Geomorphology explained 10.4% and land use 9.4% of the variation. Shared variances between different scales of habitat did not explain substantial amounts of variation among macroinvertebrate taxa. These results have, however, identified several sites in the South Fork with good potential for Best Management Practice implementation and several sites in the Middle Fork for preservation.