Simulated sensitivity of the Amazon rainforest to extreme drought

作者：Phillip Papastefanou, Thomas A. M. Pugh, Allan Buras, Katrin Fleischer, Thorsten E. E. Grams, Thomas Hickler, David M. Lapola, Daijun Liu, Christian Zang, Anja Rammig · 发表于：Environmental Research Letters · 年份：2024 · DOI：10.1088/1748-9326/ad8f48 · 被引用次数：14 · 研究领域：Hydrology and Watershed Management Studies、Flood Risk Assessment and Management、Soil erosion and sediment transport

Abstract The Amazon rainforest is highly biodiverse and has the largest extent of the remaining intact tropical forests in the world. To this day, undisturbed tropical forests act as a carbon sink by taking up about 15% of anthropogenic carbon emissions per year. However, in the past decades, a declining trend in the carbon sink capacity in the Amazon rainforest has been observed due to increased carbon losses and tree mortality. The causes are disputed, but increasing temperatures and more frequent severe droughts are potentially major drivers. We employ a novel modeling framework and hypothesize that previously rare, extreme droughts in the Amazon, such as the ones in 2005 and 2010, constitute the main cause behind the decline of the net carbon sink in aboveground biomass. Our dynamic vegetation model simulates process-based plant hydraulics and drought-induced mortality, and accounts for the diversity of strategies in plant responses to drought based on observed hydraulic vulnerability curves. The simulated impact of the 2005 drought event temporarily turned the annual Amazon net carbon sink to a carbon source of about 0.25 Mg C ha − 1 . In contrast to other dynamic vegetation models our model simulated an increasing trend in carbon losses and a declining trend in the Amazon carbon sink over the past 25 years (net sink rate of −0.015 Mg C ha − 1 year − 1 or −0.18 Mg C ha − 1 p...