Respuesta del ensamble de macroinvertebrados bentónicos en un río afectado por la actividad antrópica de la Patagonia extrandina (Provincia de Santa Cruz, Argentina)

The purpose of this study was to analyze changes in the assemblage benthic macroinvertebrates, as a response anthropogenic environmental alterations river Extra-Andean Patagonia. Four sampling surveys were carried out between March 2017 and 2019, contrasting seasons on middle course Chico River (Santa Cruz). Six stations established: two reference upstream Gobernador Gregores town four downstream at increasing distances from locality. At each station, physic-chemical variables measured macrobenthos samples collected using manual Surber-type net with 500-µm mesh. abundance taxa functional feeding groups (GFA) analyzed univariate multivariate statistical methods. Twenty-six identified; best represented oligochaetes, hirudineans, gastropods Chironomidae, Baetidae Glossosomatidae insects. those further presented higher values diversity richness GFA; Chilinidae Lymnaeidae molluscs more important together Baetidae, Gripopterygidae stations, closer town, Naididae oligochaetes Chironomidae insects dominated macroinvertebrate lower GFA. collectors-gatherers dominant these where contribution urban effluents favored detrituseating pathway opportunistic strategy. Changes composition trophic structure provide relevant information understand ecological modifications due alteration, are fundamental importance interpret biotic indices used evaluate water body quality.