Benthic macroinvertebrates community structure and physicochemical characteristics at Lauca River Basin high altitude wetlands. Altiplano, Chile.

Résumé

High Andean freshwater ecosystems are highly threatened by factors such as water availability, species invasion, and global climate change, so generating knowledge about their ecological characteristics is extremely important for making conservation decisions.The seasonal variation and relationship of physicochemical variables and the structure and composition of the macroinvertebrate community in aquatic ecosystems was analyzed. In this work, macroinvertebrate and water samples were taken from lentic and lotic ecosystems in the Lauca river basin in the Chilean highlands. The results showed a wide variation in the physicochemical variables between sites and that the main differences found in the biotic community are at the microscale level where the factors of "site" (ANOSIM global R=0.64, p=0.001) and "type of ecosystem" (ANOSIM global R=0.31, p=0.02) are more relevant than "seasonality"(ANOSIM global R=-0.003, p=0.47). The physicochemical results show Nitrogen compounds like N-Kjeldahl (p-value = 0.004), Nitrite (p-value = 0.004), Nitrate (p-value = 0.022), are the ones that most contribute to the spatial differentiation observed between sites. These results are consistent with a marked variability between high Andean ecosystems, which maintain unique environmental conditions that can be reflected in the macroinvertebrate community that inhabit them.