Zhi Liehui, Li Xiaowen, Bai Junhong, Shao Dongdong, Cui Baoshan, Mu Yonglin, Ma Tiantian, Xie Xu, Bilal Hazrat, Abdullahi Usman
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Xinjiekouwai Street No. 19, Beijing 100875, China; Hebei University of Engineering, Taiji Road No.19, Handan 056038, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Xinjiekouwai Street No. 19, Beijing 100875, China.
Sci Total Environ. 2023 Feb 10;859(Pt 1):159891. doi: 10.1016/j.scitotenv.2022.159891. Epub 2022 Nov 2.
Coastal wetlands have been enclosed by thousands of kilometers of seawalls in China to obtain extra land for rapid socio-economic development in the coastal region. Although understanding seawall-induced impacts on delta wetlands and their ecosystem can provide valuable decision-making information to support coastal management, quantifying and measuring long-term, cumulative ecological impacts of harden seawall under sea level rise (SLR) remains a vital research gap. In this study, by combining the land-use transformation trajectory analysis, ecosystem services assessment, and the SLAMM (Sea Level Affecting Marshes Model), we have explored the seawall-induced effects on temporal-spatial dynamics of tidal wetlands and the Coastal Blue Carbon storage (CBCs) in the Yellow River Delta (YRD) under the SLR by 2050 and 2100. Our study revealed that the delta wetland area would have increased by 2327.87 km after seawall removal without regard for SLR while increasing by 3050 km in 2100 in both seawall scenarios under SLR. The effects of driving processes trajectory on the changes in CBCs indicated two-sided seawall-induced impacts on the delta wetlands in the YRD, i.e., functioning as a physical coastal defense to prevent coastal erosion (before 2050) while intensifying coastal squeeze effects and quickening the loss in delta wetlands and the CBCs by hindering their inland migration under SLR. For example, the gap of CBCs between the seawall-impacting and seawall-removal scenarios would have reached at 9.94 × 10 Mg by 2050 under the SLR, and the magnitude of the final decrease effect on CBCs induced by the seawall-impacting would be nearly 5 times higher than its gain after seawall-removal in the regressive succession, while the same magnitudes in the salinization process on both scenarios. Our study has provided valuable insights for shoreline management by mitigating seawall-induced impacts on the delta wetlands and their ecosystem services such as CBCs.
为了在沿海地区获取额外土地以促进快速的社会经济发展，中国沿海湿地已被数千公里的海堤所围垦。尽管了解海堤对三角洲湿地及其生态系统的影响可为支持海岸管理提供有价值的决策信息，但量化和测量海平面上升（SLR）情况下硬化海堤的长期累积生态影响仍是一个关键的研究空白。在本研究中，我们结合土地利用变化轨迹分析、生态系统服务评估和海平面影响湿地模型（SLAMM），探讨了到2050年和2100年海平面上升情况下，海堤对黄河三角洲（YRD）潮汐湿地时空动态和海岸蓝碳储量（CBCs）的影响。我们的研究表明，在不考虑海平面上升的情况下，拆除海堤后三角洲湿地面积将增加2327.87平方公里，而在海平面上升的两种海堤情景下，到2100年将增加3050平方公里。驱动过程轨迹对海岸蓝碳储量变化的影响表明，海堤对黄河三角洲湿地有双向影响，即在2050年之前作为物理海岸防御防止海岸侵蚀，而在海平面上升时加剧海岸挤压效应，阻碍其向内陆迁移，加速三角洲湿地和海岸蓝碳储量的损失。例如，在海平面上升情况下，到2050年，受海堤影响情景和拆除海堤情景之间的海岸蓝碳储量差距将达到9.94×10吨，在退化演替中，受海堤影响导致的海岸蓝碳储量最终减少量将比拆除海堤后的增加量高出近5倍，而在两种情景的盐渍化过程中，变化幅度相同。我们的研究通过减轻海堤对三角洲湿地及其生态系统服务（如海岸蓝碳储量）的影响，为海岸线管理提供了有价值的见解。
