Macroinvertebrados bentónicos como indicadores de la calidad de agua en la microcuenca San Alberto, Oxapampa, Perú

Abstract

Objetive: To assess the macro invertebrates’ biodiversity and the ecological quality in the San Alberto micro basin (Oxapampa province, Pasco) from April to July 2013. Methods: Sampling was realized in three areas of the San Alberto basin (upper, middle and lower micro basin). In the three sites benthic macroinvertebrates in stone and sand were collected. The Andean biotic index (ABI), fluvial habitat index (IHF), Riparian-Andean vegetation quality index (QBR-And) and ecological status index (ECOSTRIAND) were estimated. Also physicochemical parameters, nutrients and metals in water were estimated. Results: We recorded a total of 123 taxa from 47 families (101 taxa in the upper basin, 77 in the middle basin and 55 in the lower basin). The higher abundance of macro invertebrates was presented in the middle basin. The ABI presented “Very good water quality” for the three areas in the basin. However, when combining the ABI with the QBR-And to elaborate the ECOSTRIAND index, the ecological status of the high and media basins were “very good quality” and the lower basin was “regular”. The stones cleaning’s sampling method allowed to collect the higher quantity of taxa. The best conditions of fluvial habitat, riparian vegetation and ecological status, after the application of the IHF, QBR-And and ECOSTRIAND indexes’ were found in the upper basin. Conclusions: The results indicate that the quality difference between riverside and fluvial habitat and the conductivity, dissolved solids and nitrates affect negatively on the water quality, and this, on the macro invertebrates’ community. The reported families as pollution sensitive (Leptophlebiidae, Oligoneuriidae, Perlidae, Anomalopsychidae, Calamoceratidae, Helicopsychidae, Odontoceridae, Blephariceridae) showed to be water quality’s biomarkers for the micro basin.