Emergent vulnerability to intensive coastal anthropogenic disturbances in mangrove forests

Mangrove forests, as one of the most productive coastal ecosystems in tropical and subtropical areas, provide multiple valuable ecosystem services for human well-being. Mangrove coverage has been declining dramatically across much of developing regions due to extensive coastal anthropogenic disturbances such as reclamation, aquaculture, and seawall construction. As coastal human activities increase, there is urgent need to understand not only the direct loss, but also the vulnerability of mangroves to anthropogenic disturbances. In this study, we evaluated spatial pattern of mangrove vulnerability based on the conceptual framework of "Exposure-Sensitivity-Resilience" using geospatial datasets in mainland China. We find that within all 25,829 ha mangroves in five coastal provinces of mainland China in 2015, nearly 76% of mangroves was exposed or threatened by anthropogenic disturbances. Coastal reclamation and aquaculture were the key threats causing mangrove vulnerability. The overall distribution of high, medium and low vulnerability was following similar trend of aquaculture distribution, which suggests aquaculture was the greatest anthropogenic disturbance agent to mangroves. Hotspot regions for mangrove vulnerability are located at the developing provinces such as Guangxi and Hainan. This study provides the first spatially explicit evidence of the vulnerability of mangrove forests to intensive coastal anthropogenic disturbances at national scale, cloud serve as a benchmark for navigating coastal ecological redline management and coastal ecosystem restoration.