Unexpected expansion and regrowth in Earth's mangrove forests over the past four decades.
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| Title: | Unexpected expansion and regrowth in Earth's mangrove forests over the past four decades. |
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| Authors: | Zhang, Zhen (AUTHOR), Murray, Nicholas J. (AUTHOR), Song, Xiao-Peng (AUTHOR), Bunting, Pete (AUTHOR), Worthington, Thomas A. (AUTHOR), Fatoyinbo, Lola (AUTHOR), Mao, Dehua (AUTHOR), Jia, Mingming (AUTHOR), Arifanti, Virni Budi (AUTHOR), Aung, Toh (AUTHOR), San Htay, San (AUTHOR), Friess, Daniel A. (AUTHOR) |
| Source: | Science. 6/4/2026, Vol. 392 Issue 6802, p1082-1087. 6p. |
| Subjects: | Mangrove forests, Regeneration (Biology), Forest canopies, Nature conservation, Coastal ecology, Climate change, Restoration ecology, Deforestation |
| Abstract: | Global mangrove forests have disappeared rapidly because of deforestation but have also regrown through natural regeneration and restoration. Yet their long-term trends in extent and canopy cover remain poorly quantified. By developing a global dataset of annual mangrove extent and canopy cover, we show that losses (long-term conversion) and degradation (canopy thinning) have both reduced since the 1980s and have been largely offset by regeneration and seaward expansion in the past decade. Consequently, global mangrove extent has shifted from net loss to net gain since around 2010 and changed only marginally from the 1980s to 2023 (−0.5% ± 1.4%). Beyond changes in extent, persistent mangroves exhibited sustained canopy accumulation. Our findings reveal the underestimated resilience of a highly threatened ecosystem, demonstrate early conservation effectiveness, and highlight halting deforestation as a priority for achieving conservation targets through natural regrowth. Editor's summary: Mangrove forests are coastal habitats that serve as nurseries for economically important fisheries. Natural disturbances such as cyclones and shore erosion, together with aquaculture, palm plantation, and rice paddy expansion, have led to global declines in mangrove forest cover, spurring national and international pledges to restore it. Zhang et al. created a 30-meter-resolution annual dataset from satellite imagery to assess how mangrove occurrence and canopy cover have changed from 1984 to 2023. Mangroves declined globally before 2010, but have mostly recovered since then, with both forest loss and degradation (declining canopy cover) rates slowing over time. Mangroves are mostly expanding into new habitats, but also regenerating in former habitat, suggesting hope for ecosystem recovery. —Bianca Lopez INTRODUCTION: Mangrove forests are globally important coastal ecosystems, playing a disproportionate role in climate regulation, coastal protection, and the maintenance of biodiversity. Despite their importance, it is generally acknowledged that mangroves have declined rapidly over recent decades as a result of deforestation and shoreline erosion; and they are widely considered one of the most threatened ecosystems globally. In the face of increasing pressures from anthropogenic activities and climate change, understanding mangrove dynamics is critical for quantifying changes in the ecosystem services they provide and for informing global conservation and restoration targets. RATIONALE: Mangrove forests can partially recover lost area through natural regeneration and can also expand by colonizing newly formed tidal flats. In addition to changes in areal extent, mangrove stands can undergo substantial canopy thinning or accumulation without experiencing outright loss or gain. It remains unclear to what extent mangrove regeneration and expansion have offset historical losses globally, and subtle but widespread variations in canopy condition within persistent mangroves remain largely unquantified. To address these gaps, we developed an annual global dataset of mangrove extent and canopy cover spanning the past four decades using long-term Landsat observations. This framework enables a unified assessment of both binary area change (loss and gain) and continuous canopy dynamics within persistent mangrove forests, including degradation (canopy thinning) and growth (canopy accumulation). RESULTS: Global mangrove loss rates reduced substantially from the 1980s to 2023, while mangrove gains increased markedly over the same period. As a result, global mangrove extent shifted from net loss to near gain in the recent decade, driven primarily by natural seaward expansion. This recent increase in gains has offset a large fraction of historical losses, resulting in only a marginal net loss in global mangrove area since the 1980s. Beyond areal change, we detected widespread mangrove degradation, which was more extensive than loss and was strongly associated with tropical cyclones, although degradation rates also declined over time. Meanwhile, persistent mangrove forests continued to accumulate canopy cover through natural growth, leading to an expansion of dense-canopy mangroves. CONCLUSION: Our findings demonstrate that even highly disturbed ecosystems such as mangroves retain a strong resilience for recovering from loss or degradation. By highlighting the dominant role of natural expansion and regeneration, our results suggest that halting deforestation should be prioritized to meet current global mangrove area targets. Furthermore, those newly established mangroves represent an important opportunity for conservation, because young stands require time to accumulate carbon and fully recover the ecosystem functions of the mangroves that they replaced. Understanding the mechanisms governing mangrove expansion and regeneration is therefore essential for guiding effective mangrove restoration. Global patterns and regional trajectories of mangrove area change (1984–2023).: Colors indicate net percentage change in mangrove area at the 1° grid cell scale. Insets show regional mangrove area trajectories at annual frequency. [ABSTRACT FROM AUTHOR] |
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| Database: | Psychology and Behavioral Sciences Collection |
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