Meeting Abstract
P3.35 Wednesday, Jan. 6 Elevation gradient affect aquatic macroinvertebrate assemblages in tropical island streams HERNANDEZ-GARCIA, P.J.; UNIVERSITY OF PUERTO RICO, RIO PIEDRAS CAMPUS pabloj82@yahoo.com
The “River Continuum Concept” presents how the macroinvertebrate functional groups changes from headwaters to the estuary, depending in channel width, forest cover and organic material inputs. Studies in spatial variation are focus in these changes, but few of them had observed if the elevation has any effect to the biota. In this study, we evaluate how elevation affects aquatic macroinvertebrate assemblages in a tropical island. Eighteen streams were selected in an elevation gradient from watersheds draining “El Yunque National Forest” in Puerto Rico. These streams were selected based in channel width (from 1 to 3.5m) in the less human impacted areas, to be similar to headwater streams. In each stream, samples were collected from the two main microhabitat (five from pools and five from riffles) using D-shape net in a standard area of 90cm2. Samples were taken to the laboratory, where macroinvertebrates were extracted and classify under the microscope. Insects were classified to family level. In addition, Crabs and shrimps were classified to specie. Along the elevation gradient, we found similar aquatic macroinvertebrate assemblages, from which the most abundant were insects of family Leptophlebiidae. This result support the assumption of the “River Continuum Concept” that present that streams with similar channel width, forest cover and organic material inputs will have similar macroinvertebrate assemblages.
