Interannual lake fluctuations in the Argentine Puna: relationships with its associated peatlands and climate change
2019
Casagranda, Elvira | Navarro, Carlos | Grau, H Ricardo | Izquierdo, Andrea E.
High elevation ecosystems are likely more sensitive to climate change. But, due to paucity of instrumental records, such effects are poorly studied, particularly in mountains outside Europe and North America. Here, we quantified water body area fluctuations for the last 32 years in 15 lakes spread over an area of 14.3 million ha in the Argentine Puna, through the classification of Landsat images; and we quantified peatlands NDVI (a proxy of vegetation productivity) from MODIS images. We evaluated the pairwise similarity between lakes interannual fluctuations and their relationship with climate models (TRMM 3B43 v7; CRU TS 4.10) and potential controls (ENSO index); and the correlations between water body area and the NDVI variation of its associated peatlands. Lakes were grouped in two clusters defined by their synchronic water body area variability and these clusters define two main geographic zones: NE and SW. Consistent with previous observations of an overall aridization trend, water body area generally decreased but showed large variability among lakes. Peatlands productivity was more correlated with lake variability than with modeled precipitation, and lake water body area was weakly related to indices of ENSO, providing an additional tool to relate local climate with continental and global climate models. The analysis shows that lake behavior is highly variable spatially and temporally, and that satellite-based monitoring is a valuable tool for assessing ecological conditions of wetlands in the region, characterized by the lack of climatic instrumental records; and to explore the vulnerability of wetlands to climate change.
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