Enhanced vulnerability of coastal wetland to extreme flooding under climate warming: field experimental evidence in the Yellow River Delta

Coastal wetlands around the world are highly vulnerable to flooding as a result of rising sea level. Resilient wetlands theoretically stabilize vegetation production to resist the negative impacts of flooding. However, there is little understanding of whether wetland is more vulnerable to extreme flooding under climate warming. Here, we conducted a field experiment to assess the effects of warming on above-ground net primary production (ANPP) in a coastal wetland in the Yellow River Delta of China, where the dominant species are Phragmites australis and Suaeda glauca. During the three years, there was an extreme precipitation event in 2016 and that lead to a 72.4 cm-height flooding. We find that warming lowers the temporal stability of ANPP. We also find that warming can shift the dominant species of community and the new community does not resist extreme flooding. This is because warming enhances the soil salinity and Suaeda glauca has higher salinity tolerance can replace Phragmites australis which is the dominant species in control plots. However, the height of Suaeda glauca is lower than the flooding depth when the extreme flooding occurs. As a result, Suaeda glauca does not survival and accumulate biomass. Our results indicate that the coastal wetland in eastern China will be more vulnerable in the face of climate warming and extreme flooding associated with sea-level rise.