Abstract

BERTORA, Andrea; GROSMAN, Fabián; SANZANO, Pablo  and  ROSSO, Juan José. Composición y estructura de los ensambles de peces en un arroyo pampeano con uso del suelo contrastante. Rev. Mus. Argent. Cienc. Nat. [online]. 2018, vol.20, n.1, pp.51-63. ISSN 1853-0400.

Aquatic ecosystems and their biotic communities in the Pampa Plain have been negatively affected by the intensification of land use during the last years. In this scenario, streams are particularly vulnerable. This work characterizes the fish communities and riparian conditions of del Azul stream in different reaches with contrasting land uses: agricultural, urban and livestock. Riparian conditions and ichthyological samplings were conducted during two summers in the three studied sites. In order to characterize riparian conditions and fish communities different indices and metrics were calculated. The empirical relationships between fish metrics and two pampean riparian indices were calculated. The riparian condition differed among land uses, being lowest in the urban section. A total of 1180 fishes of 15 species were captured. The fish community structure of agricultural reach was diametrically different from the others. However, the species composition was similar between reaches. Fish richness was highest at the livestock reach whereas the agricultural reach showed the largest diversity. The abundance of Corydoras paleatus and the relative abundance of Siluriformes were inversely related with the riparian condition. Instead, the abundance of Oligosarcus jenynsii presented the opposite pattern. Fish communities and riparian conditions responded to different land uses and it also was evidenced an association between some fish community attributes and riparian condition. These results contribute to the basic knowledge needed for an efficient conservation and management of the freshwater resources.

Keywords : Pampa plain; Fish community; Riparian index; Use of land.