The trajectory of wetland change in China between 1980 and 2020: Hidden loss and restoration effects

This study is led by Prof. Dehua Mao and Prof. Zongming Wang (Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences). Although it looks like a simple data analysis, researchers prepared this work and generated the wetland product over five years. The hybrid object-based and hierarchical classification approach was applied to over 53,000 scenes of Landsat images acquired between 1980 and 2020 and to create a national wetland mapping product (China_Wetlands) for six periods (e.g., 1980, 1990, 2000, 2010, 2015, and 2020). Moreover, based on the China_Wetlands, they exhibits diverse Chinese wetland changes, and presents their trajectory in response to climate change and human impacts in the past four decades. "I think it’s a great work" Prof. Yeqiao Wang (University of Rhode Island) says.

There was a substantial wetland shrinkage in area before 2015, with a small rebound between 2015 and 2020. The net loss was ~60.9 × 10³ km², 12% of the area in 1980. Although this area value looks like small, we must see the hidden loss of wetlands. The loss of natural wetlands was hidden by human-made wetland gain with an offset of 15.6 × 10³ km². About 14.0 × 10³ km² expansion of surface water extent also hides the loss of vegetated wetlands. “This study provides important data information. The ‘zero net loss target’ is not appropriate for sustainable wetland conservation”, Zongming Wang Says.

“Sustainable management and effective conservation of wetlands require a focus not only on wetland areas but also on the landscape structure and the small patches and areas of wetlands that deliver important ecosystem services. Enhanced protection accompanied by increased ecological projects and improved management systems as well as future changes in response to diverse climate change must be assessed. Unreasonable internal conversions among wetland types and the invasion of alien species should be controlled”, Prof. Ming Jiang (Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences) Says

“China_Wetlands will be a critical wetland dataset for ecological research and assessment of national and global environmental objectives”, Wenping Yuan (Peking University) Says.

“We are pleased to share this important wetland product. In fact, many scholars have already applied to use the product”, Dehua Mao Says.

 

See the article:

The trajectory of wetland change in China between 1980 and 2020: Hidden loss and restoration effects

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