Resumen

HANKEL, Guillermo E; EMMERICH, Daniel  y  MOLINERI, Carlos. Benthic macroinvertebrates of arid environments of northwestern of Argentina. Ecol. austral [online]. 2018, vol.28, n.2, pp.435-445. ISSN 1667-782X.

In the Northwestern region of Argentina (NOA), an extensive part of the territory is occupied by arid environments, vulnerable to the development of human economic activities. The aim of this study was to provide basic information about the benthic macroinvertebrate assemblages of rivers in this area, and to use different biotic indices to prove their power to predict river ecological status. Fifteen streams and rivers were sampled in the provinces of Catamarca and La Rioja, in different occasions, accounting for a total of 23 sites. Samples were taken with Surber net (two or three in each site) and environmental parameters were recorded. Canonical correspondences analyses (CCA) were performed to study the relationships between environmental data and the macroinvertebrate assemblage structure, and different biotic indices were calculated for each site. A total of 59 taxa were found, being Diptera the richest group (12 families). The highest alfa diversity was 29 taxa, while the lowest was 1. The best represented taxa were Andesiops peruvianus, Meridialaris tintinnabula, Austrelmis (larva), Orthocladiinae, Smicridea, Helicopsyche and Heleobia. The CCA showed that electric conductivity and streambed width were important factors that influence the macroinvertebrate assemblage structure. The biotic index with the best ecological performance was the “índice biótico de las Sierras de San Luis” (IBSSL). Diversity in the studied sites was similar to those of other sites from arid environments of Argentina, like Cuyo (San Luis and Mendoza provinces) and Catamarca province, but lower than those of the Patagonian sites. The IBSSL proved to be useful to be applied in the region, but more detailed studies are needed, including polluted sites to improve their explanatory value.

Palabras clave : Aridity; Monte ecoregion; Catamarca province; La Rioja province; Streams and rivers.

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