Unexpected canopy gain in Earth’s mangrove forests linked to natural expansion and regrowth

Zhen Zhang, Nicholas Murray, Xiao-Peng Song, Pete Bunting, Thomas Worthington, Lola Fatoyinbo, Dehua Mao, Mingming Jia, Virni Budi Arifanti, Toe Aung, San San Htay, Daniel A. Friess

Mangroves have disappeared rapidly due to deforestation and sea-level rise but can also recover through natural regrowth and restoration. However, their long-term trajectory in area and canopy cover remains highly uncertain. By developing a global mangrove canopy density dataset, we show that mangrove loss (conversion to other land uses) and degradation (reduction in canopy density) have been reduced and have been largely offset by regeneration and natural seaward expansion over four decades. As a result, global mangrove extent has reversed from net loss to net gain and shown a decline of only around -1% from the 1980s to 2023, although most newly established mangroves still provide limited ecosystem services because they are not yet mature enough to compensate for the loss of older forests. Meanwhile, persistent mangrove forests keep accumulating canopy density, suggesting natural growth and potential underestimation of blue carbon gains in current area-based assessments. Our results reveal the underestimated resilience of a highly threatened ecosystem and suggest halting deforestation as a priority to meet global restoration targets through natural regrowth.