Altitudinal replacement of Ephemeroptera in a Subtropical River

DOMINGUEZ, EDUARDO; BALLESTEROS VALDEZ, JUAN M.

HYDROBIOLOGIA

Kluwer Academic Publishers

Año: 1992 p. 83 - 88

0018-8158

An altitudinal sampling transect was established in a subtropical mountain river to determine if replacement between two mayfly faunal components (oligostenothermal and polystenothermal) occurred. We detected three main groups: Group A, species with high abundance at higher stations, declining abruptly downstream; Group B, species with maximum abundance at lower elevations; either declining abruptly upstream or absent from higher elevations; and Group C, species with little elevational change. The physical and chemical variables did not change abruptly with altitude during our winter sampling, although the distribution of groups A and B species did. The observed distributional patterns of groups A and B do not appear to be correlated with variations in the physical and chemical variables surveyed.