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Rebound in China’s coastal wetlands following conservation and restoration


The coastal zone of China has experienced large increases in population, economy and urbanization since the early 1980s. Many studies have reported the loss, degradation and fragmentation of coastal wetlands in China at local to regional scales. To date, at the national scale, our knowledge of the spatial distribution, inter-annual variation and multi-decadal trends of coastal wetlands in China remains very limited. Here we analysed ~62,000 Landsat-5, -7 and -8 images over the period 1984–2018 and generated maps of coastal wetlands for individual years in China at 30-m spatial resolution. We found that coastal wetland area significantly decreased between 1984 and 2011. We also found a substantial increase in saltmarsh area and a stable trend of tidal flat area since 2012, driven by reduced anthropogenic activities and increased conservation and restoration efforts. These coastal wetland maps for the period 1984–2018 are invaluable for improvement of coastal wetland management and sustainability in China.

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Fig. 1: Maps of coastal wetlands in four river deltas of China: 1985, 1995, 2005 and 2018.
Fig. 2: Coastal wetland losses and gains in three major Chinese river deltas, 1984–2018.
Fig. 3: Inter-annual trends for coastal wetland areas by province in China, 1984–2018.
Fig. 4: Inter-annual changes for coastal wetland areas in China, 1984–2018.
Fig. 5: Timeline of major policies and laws in regard to wetlands and coastal wetlands and their impacts on inter-annual changes in coastal wetland areas, ACAs and new ISAs in China, 1984–2018.

Data availability

All datasets used in this study are publicly available online (Supplementary Table 7). The coastal wetlands maps are available from the corresponding author upon reasonable request and will be made available to the public. Source data are provided with this paper.

Code availability

The codes used in the calculations of coastal wetlands are available upon reasonable request.


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X.W., B.L. and X. Xu were supported by the National Natural Science Foundation of China (grant nos. 41630528 and 32030067). X. Xiao and Y.Q. were supported by the US National Science Foundation (grant no. 1911955). X.W. and X. Xu were supported by the China Postdoctoral Science Foundation (grant nos. 2021TQ0072, BX20200094 and 2020M681164). L.P. was supported by the Natural Science Foundation of Guangxi Province (grant no. 2017GXNSFBA198009). X.W. was supported by the China Scholarship Council (grant no. 201906100124). We thank Q. He from Fudan University for discussions and literature that helped improve the Discussion section of the manuscript.

Author information




X. Xiao, X.W. and B.L. designed the study. X.W. carried out image data processing. X.W., X. Xiao and B.L. led interpretation of the results and writing of the manuscript. Z.Z., B.C., Y.Q., X.Z., J.D. and D.L. contributed to image data processing. X. Xu, Y.Q., X.Z., J.D. and L.P. contributed to interpretation and discussion of results.

Corresponding authors

Correspondence to Xiangming Xiao or Bo Li.

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The authors declare no competing interests.

Additional information

Peer review information Nature Sustainability thanks Andrea Ghermandi and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Notes 1–7, Figs. 1–22, Tables 1–7 and references.

Reporting Summary

Source data

Source Data Fig. 2

Coastal wetland areas in three major river deltas of China, 1984–2018.

Source Data Fig. 4

Coastal wetland areas in China, 1984–2018.

Source Data Fig. 5

Coastal wetland areas, ACAs and new ISAs in China, 1984–2018.

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Wang, X., Xiao, X., Xu, X. et al. Rebound in China’s coastal wetlands following conservation and restoration. Nat Sustain (2021).

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