Meeting Abstract

P1.49  Monday, Jan. 4  Comparisons of the decapod community structure in urban and natural streams in Puerto Rico PEREZ-REYES, OMAR*; CROWL, TODD A.; UTAH STATE UNIVERSITY, LOGAN macrobrachium@yahoo.com

Many tropical streams have been altered by water diversions, channel modification, introduced species, and water quality degradation. In Puerto Rico, watersheds range from montane, relatively pristine to highly degraded, and offer an opportunity to examine the impacts of human disturbances on native stream communities. Populations of native decapods, water temperature, pH, and DO were studied in 3 sites encompassing urban, sub-urban and pristine streams. Thirteen decapod taxa were recorded from the 3 streams. The abundance of species and community structure showed variations among the urban and sub-urban watersheds and the natural sites; ecologically relevant species (Atya, Epilobocera and some Macrobrachium spp.) were completely missing from the urban stream sites. The variations in decapod communities among watersheds correlated with the degradation of the physical-chemical environments, clearing of the riparian zones, and the introduction of exotic fauna to those portions of the rivers. Many nonnative aquatic species are better adapted than native species to degraded habitats (higher temperature and sedimentation); once established in these habitats, they can cause further reduction in native populations through competition, predation, and the introduction of parasites. Understanding the relationship between habitat alteration and aquatic community structure will be critical for developing enhanced conservation strategies for the impacted urban streams.