生态-地貌耦合过程对盐沼形态特征和演变规律的影响机制

Salt marshes are valuable intertidal ecosystems and natural barriers for the coastal areas. The roles of static salt marsh vegetation in wave attenuation and sedimentation enhancement have been well studied, while their geomorphic effects are less documented. In real marshes strong interactions exist between physical processes such as flow, sediment transport and morphology change, and ecological processes such as vegetation evolution, which can control the morphological patterns of salt marshes. In this project we will focus on the coupled eco-geomorphological evolution of mudflat-marsh systems, and investigate their effects on the ontogeny processes and resulting morphology patterns in both real and idealized morphological settings. First, two abandoned estuaries in the modern Huanghe (Yellow River) delta, which have totally different vegetation covers and morphology evolution trends, will be investigated through field measurements and numerical modeling in order to describe the detailed coupling process between vegetation and morphology change. Secondly, the subgrid, eco-geomorphology model developed by the author will be extended to include the wave-induced marsh edge lateral erosion process. Then the model will be used to explore the controlling effects of vegetation and waves on the morphological configurations of the mudflat-marsh-channel system and the geometry patterns of the channels, through systematic numerical experiments under different geomorphic settings and environmental factors. Quantitative analysis will be performed with the modeling results. Featured with an interdisciplinary approach, this project is expected to deepen our understanding on dynamics of vegetated coastal systems and contribute to their utilizations and conservations.

滨海盐沼湿地是重要的生态环境系统和天然的海岸防护屏障。以往研究多集中于静态盐沼植被的消浪、促淤作用，对植被的地貌效应研究较少，而实际盐沼中水、沙运动等物理过程，与植被演化等生态过程之间存在着紧密的耦合作用，对盐沼的地貌格局和形态特征具有强烈的塑造作用。本项目聚焦于盐沼的植被-地貌耦合动力过程，研究其对典型潮滩盐沼系统发育与演变的影响机制。内容包括：1）选取黄河三角洲两处植被覆盖完全不同、地貌演化完全不同的废弃河口为研究区，将现场观测与数值模拟紧密结合，阐述盐沼植被与地貌演化之间的耦合机制；2）基于申请人前期开发的亚网格生态-地貌模型，拓展考虑波浪对盐沼前缘的侧向侵蚀过程，模拟分析不同地形和动力条件设置下的植被-地貌耦合演变过程，量化植被、波浪等关键环境动力因素对“潮滩-盐沼-潮沟”系统的地貌格局和潮沟形态特征的影响规律。研究具有多学科交叉特色，成果可为滨海湿地的保护提供理论支持和模型工具。

滨海盐沼湿地是重要的生态环境系统和天然的海岸防护屏障。本项目以黄河三角洲潮滩湿地为依托区域，开展了滨海湿地动力演变规律和机制方面的研究。研究内容包括：首先，构建了物理过程和生态过程更为完备的滨海盐沼演变模型，揭示了植被对盐沼地貌演变的影响规律和作用机制；其次，以黄河三角洲为目标区域，研究了河口地区自然滨海湿地的演化规律，探讨了湿地演变与黄河径流、来沙量的关系；最后，建立了黄河三角洲水动力、泥沙输运与地貌演变模型，并讨论了调水调沙对于黄河三角洲地貌演变的短期和中长期效应。研究成果对于增强对滨海湿地动力过程的理解、滨海湿地修复与保护具有一定的参考价值。项目资助下，共计发表标注项目资助的SCI论文8篇，代表性成果发表在Coastal Engineering, Applied Ocean Research, Science of the Total Environment等国际著名期刊上，项目负责人在项目执行期内参加国内外会议3次，做学术报告2次。基于本项目的部分研究内容，项目负责人以第三完成人获得了2019年教育部技术发明二等奖。