Reconstructing trophic changes in two lakes located in Nahuel Huapi National Park, Patagonia Argentina using non-biting midges (Diptera: Chironomidae)

MONTES DE OCA; PLASTANI; MOTTA; MASSAFERRO

Reno

Congreso; ILIC6; 2014

International Limnogeological Asociation

Lakes located in remote areas are good reference ecosystems for the implementation of paleoenvironmental studies, for they provide baseline information about past climates and trophic history. In protected areas, this kind of long term studies can help for the early detection of human impacts that may affect lake conditions, providing tools for management policies. Subfossil chironomids (Diptera: Chironomidae) are useful paleoindicators due to their specific response to different environmental factors. The aim of this work is to study chironomids combined with fossil pigments and organic matter, to provide information about the trophic history of two sediment cores from high altitude lakes in Nahuel Huapi National Park (ca. 41°S- 71°W), Rio Negro, Argentina. We observed an increase on pigment and organic matter, and a change in chironomid taxa in the most recent sediments from both lakes. These variations took place during the last 40-60 years according to 210Pb dating, and could be related to the increase in human activity in the area. Nevertheless, further complementary information would be needed in order to disentangle the effects of stressors, and to understand the chironomids record in terms of the interaction between climatic, trophic and lake processes dynamics at this region.