| Popis: |
The faunistic composition of the mayflies community was analized in Potrero y Chorrillo streams at 7 sampling sites. Six taxa which belong to three families were collected: Tricorythodes popayanicus Dominguez, Leptohyphes sp., Baetis sp., Baetodes sp., Dactylobaetis sp. and Caenis sp.. The cluster analysis among the study sites showed two well defined groups, the first one grouped the sites above dams and the second below dams. In the below dam sites a decrease of the species richness was observed. Baetis sp., was the only species that was present in the whole fluvial channel studied and it dominated downstream of impoundments. Tricorythodes popayanicus was dominant in the rest of the locations, except in one tributary, in which Caenis sp. predominated. Dactylobaetis sp. was completely eliminated downstream of the impoundment. Other species were also affected to varying degrees. The importance of the Ephemeroptera species varied along the longitudinal profile of the river system, mainly related to the effects of dams. |
