Effect of climate-driven water level fluctuations on a large Neotropical wetland (Esteros del Iberá, Argentina).

ÚBEDA SÁNCHEZ, B.; NEIFF, J. J.; DI GIÁCOMO, A.S. ; LOISELLE, S.; POI DE NEIFF, A. S.G.; GÁLVEZ, J.A.; CASCO, S.L.; CÓZAR CABAÑAS, A.

Cape Town

Congreso; 1 Congreso de la Sociedad Internacional de Limnología (SIL); 2010

Sociedad Internacional de Limnología (SIL)

Climate change will establish new hydrological scenarios worldwide, and diversity, composition and functioning of the wetlands would have to adjust to these new hydrological patterns. In this work, we use the IPCC climatic projections to assess the range of the potential variations in water level in Iberá wetland (Argentina). We found a trend of water level decline and increasing water level fluctuations. Empirical analyses of extreme climatic events and mechanistic approaches were combined to find insights into the possible responses of wetland vegetation, fauna and water bodies. The frequent droughts occurred between 2003 and 2007 in Iberá led to major declines in the water drainage of the wetland. Using this particular circumstance, we compare the spatial patterns of the vegetation diversity and fauna density during a scenario characterized by abnormally low water levels and a reference scenario. A total of 173 littoral samplings were used to analyze the changes in vegetation diversity in the permanent waterbodies. Macro-fauna (birds, mammals and reptiles) abundance was analyzed from aerial censuses including the lakes as fauna hotspots in the wetland. On the other hand, an original limnological model was coupled to the hydrological projections. Results showed insignificant effects of the water warming on the lakes functioning. Changes in the lakes were mainly related to the water level fluctuations and the dilution process. Model outputs were discussed in relation to the historical data and the alternative stable state theory.