Abundance and altitudinal distribution of Ephemeroptera in lotic Andean-Patagonic system (Argentina).

MISERENDINO, M. L; PIZZOLON LINO

Trends in Research in Ephemeroptera and Plecoptera

Kluwer Academic/Plenum Publishers

Lugar: New York; Año: 2001; p. 135 - 142

The distribution patterns of the Ephemeroptera found in a river system of the Patagonian Cordillera (Chubut, Argentina) were analysed. The system extends along a 1000-m altitudinal gradient and exhibits a marked perturbation in its middle reach owing to the organic sewage discharged by the city of Esquel. Eight ephemeropteran species were identified. Species distributions were determined by altitude, stream order, water temperature, conductivity, total alkalinity, and biochemical oxygen demand. Metamonius sp and Meridialaris chiloeensis proved to be stenothermic, M. laminata characterized the reaches of higher stream order, while Baetis sp and M. chiloeensis were the species most affected by organic sewage.