Abstract

The Ascotán salt pan is an extreme freshwater system in the Southern Altiplano of Chile (17°-22°S). Its origin has been traced to the presence of the paleolake Minchin approximately 0.0117 Ma. Currently, this system has been experiencing important changes such as seasonal temperature increase, higher water evaporation and water depletion. The eastern side of the Ascotán salt pan is conformed by twelve isolated springs that host a unique biodiversity in the Altiplano. The aim of this research has been to characterize the composition and structure of benthic macroinvertebrates community in relation to the environmental characteristics in five springs of the Ascotán salt pan. We found significant differences in the community structure and composition among the springs (PERMANOVA: Pseudo-F = 8.417; P < 0.01). These results were related to differences in the salinity concentrations of several anions and cations of the springs. Regarding benthic fauna 24 families were identified. The most abundant taxa were the Elmidae, Hydrozetidae, Hyalellidae, and Cyprididae. Recently the uncontrolled water and Boron extraction due to mining could affect freshwater biodiversity. Therefore, legal measures need for conservation of this extreme ecosystem in the Southern Altiplano.