Greater trend and interannual variability in productivity of mangroves compared to terrestrial forests

Z. ZHANG, X. LUO, D. A. FRIESS, S. WANG , Y. LI , Y.LI

Department of Geography, National University of Singapore, Singapore, Singapore

Mangrove forests are one of the most productive ecosystems and have outsized importance in offsetting anthropogenic greenhouse gas emissions. As they are located in the coastal environment and develop unique ecophysiological characteristics, mangroves are expected to respond differently to climate compared to terrestrial forests. The climate sensitivities of mangroves, however, have not been clearly delineated at the global scale. Here we use multiple satellite observations to examine the changes in the productivity of global mangrove forests and their nearby terrestrial counterparts, the evergreen broadleaf forests (EBFs), over the past two decades and quantify their differences in climatic sensitivities. We found 38.4% of mangroves and 34.2% of EBFs under similar climate conditions experienced significant increases in their gross primary productivity. Mangroves exhibited greater trends and interannual variability in productivity than EBFs on 69.8% and 75.3% of their co-occurred coasts, mainly driven by the stronger CO₂ fertilization effect and higher sensitivity to the precipitation of mangroves. Our results indicate that mangroves will have a faster increase in ecosystem-level productivity than terrestrial forests in a CO₂-rich future but may suffer more from deficits in water availability, highlighting the key disparity between