Abstract
Ecological restoration of coastal wetlands has contributed to reversing biodiversity loss, but its effects on greenhouse gas emissions remain poorly understood. Here, we present three years of field measurements from restored wetlands in Southeast China, comparing areas with and without dense migratory waterbird congregations. Results indicate that carbon dioxide and methane emissions were significantly higher in waterbird-influenced plots, but only during autumn and winter when bird populations peaked (P < 0.001). Bird droppings increased nutrient availability in the soil and water, which in turn stimulated microbial activity and enzymatic reactions. Meanwhile, bird-induced oxygen consumption promoted anaerobic conditions, which increased the abundance of methanogens while suppressing methanotrophs. These combined effects drove seasonal surges in greenhouse gas emissions. Collectively, our findings identify migratory bird aggregation as a key driver of seasonal emission hotspots in restored wetlands, and highlight the need for long-term, high-frequency monitoring frameworks that capture these seasonal biological pulses when assessing the climate benefits of wetland restoration projects.
Acknowledgements
We thank Assoc. Prof. Huaizhou Zheng (Institute of Geography, Fujian Normal University) for providing field observations of bird aggregations that inspired this research. We also thank the reviewers for their constructive comments, which improved the manuscript.
Funding
The work was supported by the National Natural Science Foundation of China (Grant Nos. 42371100 and 42401118), the Natural Science Foundation of Fujian Province, China (Grant No. 2025J010028), the Hubei Provincial Natural Science Foundation of China (Grant No. 2026AFC1145), the Basic Research Funds for National Research Institutes of IHEG (Grant No. SK202305KF19).
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Zhang, Y., Li, S., Yang, P. et al. Migratory bird aggregation drives seasonal greenhouse gas hotspots in restored wetlands.
Commun Earth Environ (2026). https://doi.org/10.1038/s43247-026-03853-w
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DOI: https://doi.org/10.1038/s43247-026-03853-w
Source: Ecology - nature.com
