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Wednesday, June 6, 2007 - 10:30 AM
205
Assesing the effect of land use patterns on the ecological health of streams in a tropical urban watershed in Puerto Rico
Rebeca De Jesus, Biology, University of Puerto Rico, Anexo Facundo Bueso, P.O. Box 21910, San Juan, PR 00931 and Alonso Ramirez, ITES, University of Puerto Rico, Anexo Facundo Bueso, P.O. Box 21910, San Juan, PR 00931.
Urbanization in Puerto Rico is increasing at a rapid rate and our understanding of how stream ecosystems are affected is critical to protect streams. Aquatic ecosystems are especially sensitive to land use patterns as they receive surface runoff from all areas where urban activities occur, thus urbanization can modify the physical and biological structure of streams. In this study we assessed how land use patterns are related to water quality and macroinvertebrate assemblages in an urban river in Puerto Rico. We sampled 18 sites within the Rio Piedras watershed (San Juan, PR) for macroinvertebrate composition, water physicochemistry and physical structure. Land use within the Rio Piedras was classified as percentage of vegetation and impervious surface cover within the eighteen sub watersheds. Land use patterns were related to stream variables using ordination analyses. We observed better ecological health in streams within sub watersheds with high percent vegetation cover. In contrast, we found no relation between riparian buffer characteristics and the stream variables. Our study suggests that riparian buffer zones are not capable of protecting urban stream ecosystems within this intensely urbanized area. Therefore, development plans should include additional strategies to protect streams in urbanizing areas, such as better runoff control.