Data of Climate factors rather than human activities controlled NDVI trends across wet meadow areas in the Andes Centrales of Argentina
In the Andes of southern South America, wet meadows are much more productive than nearby arid areas. Human activities, along with climate variations may reduce the productivity of these ecosystems. However, we do not know what the relative effect of climate and human activities on their degradation status is. Here, we quantified the trends of NDVI over time for wet meadow areas under similar regional climate drivers, but with different land management. One of the levels is associated with an ongoing open pit mining project, the second level is associated with a nearby watershed where the wet meadow areas in it are under human activities as grazing or irrigation but are not affected by open pit mining, and the third one is associated with a national park where the wet meadow areas in it are neither affected by mining nor other activities as domestic herbivores grazing. As well, we analyzed the temporal relationship between NDVI and climate variables through global, ENSO, and local, precipitation and temperature, descriptors for all wet meadow areas within each one of the three zones. Lastly, we evaluated the human activities effect by removing the climate variables effect, through the trends in the residuals of the climate model (RESTREND). Independently of land management, NDVI trends were mainly negative and affected 56% of the wet meadow areas. The climate model indicated that NDVI increased under La Niña, cool and wet years. Regarding land management, the degradation level was similar across the contrasted land management. Our results suggest that climate factors rather than human activities influenced the degradation process in these areas.