Influência do El Niño e La Niña na cobertura vegetal do sul do Amazonas

Abstract

The ecologically vital southern region of the Amazon is impacted by climate variability induced by the El Niño-Southern Oscillation (ENSO). Understanding vegetation responses to these events is crucial for conservation and management strategies. This study examined the effects of strong and weak El Niño (2015–16, 2004–05) and La Niña (2010–11, 2017–18) events on precipitation, temperature, humidity, and the Normalized Difference Vegetation Index (NDVI) across five municipalities in the southern mesoregion of Amazonas, Brazil. Remote sensing data from the Landsat satellite were utilized, along with climatic data collected from CPC, NOAA, and ECMWF–ERA5.Results demonstrated that El Niño consistently reduced precipitation (deficits reaching -50.92 mm in the rainy season), increased temperatures (seasonal anomalies up to +1.55°C), and generated negative NDVI anomalies (vegetation activity reductions peaking at -0.05), indicating hydrothermal stress. In contrast, La Niña events, although enhancing precipitation (anomalies up to +31.19 mm) and decreasing temperatures (anomalies up to -2.35°C), led to heterogeneous NDVI responses. Some locations showed increased vegetation vigor (anomalies up to +0.05), whereas others, like Boca do Acre, experienced reductions (anomalies down to -0.04), suggesting limitations imposed by secondary factors such as waterlogging or insufficient solar radiation.The study concludes that vegetation response to ENSO in southern Amazonas is spatially variable, complex, and non-linearly dependent on event intensity, with significant implications for regional vulnerability. Continuous monitoring and adaptive management strategies are essential, aligning with Sustainable Development Goals (SDGs) 13 and 15.