Vulnerability of Amazonian forests to repeated droughts

作者：Liana O. Anderson, Germano Ribeiro Neto, Ana Paula Martins do Amaral Cunha, Marisa Gesteira Fonseca, Yhasmin Mendes de Moura, Ricardo Dalagnol, Fabien Wagner, Luiz E. O. C. Aragão · 发表于：Philosophical Transactions of the Royal Society B Biological Sciences · 年份：2018 · DOI：10.1098/rstb.2017.0411 · 被引用次数：151 · 研究领域：Remote Sensing in Agriculture、Plant Water Relations and Carbon Dynamics、Environmental and biological studies

Extreme droughts have been recurrent in the Amazon over the past decades, causing socio-economic and environmental impacts. Here, we investigate the vulnerability of Amazonian forests, both undisturbed and human-modified, to repeated droughts. We defined vulnerability as a measure of (i) exposure, which is the degree to which these ecosystems were exposed to droughts, and (ii) its sensitivity, measured as the degree to which the drought has affected remote sensing-derived forest greenness. The exposure was calculated by assessing the meteorological drought, using the standardized precipitation index (SPI) and the maximum cumulative water deficit (MCWD), which is related to vegetation water stress, from 1981 to 2016. The sensitivity was assessed based on the enhanced vegetation index anomalies (AEVI), derived from the newly available Moderate Resolution Imaging Spectroradiometer (MODIS)/Multi-Angle Implementation of Atmospheric Correction algorithm (MAIAC) product, from 2003 to 2016, which is indicative of forest's photosynthetic capacity. We estimated that 46% of the Brazilian Amazon biome was under severe to extreme drought in 2015/2016 as measured by the SPI, compared with 16% and 8% for the 2009/2010 and 2004/2005 droughts, respectively. The most recent drought (2015/2016) affected the largest area since the drought of 1981. Droughts tend to increase the variance of the photosynthetic capacity of Amazonian forests as based on the minimum and maximum AEVI analysis. However,...