弹性海岸：台湾海峡沙质海岸地貌动力与植被生态的响应关系

Sandy beaches are one of the most common coastal formations located at the boundary between the continents and oceans. In the face of global change, sandy beaches are coastal ecosystems with growing relevance; They provide key ecosystem services, such as storm buffering, nutrient cycling, water purification, nursery habitats for resource species, and feeding-breeding habitats for focal species, and have also become nodes for economic development and cultural use (ca. 40% of the world's population lives within 100km of the coast). As a result, beaches face a range of threats, primarily from extractive use, habitat modification and development, sea-level rise and coastal squeeze, along with increased pollution impacts and differing erosion rates due to hard engineering of defences near major cities. .The use of vegetation to help reduce erosion, maintain the geomorphology and restore ecosystem balances on sandy beaches could be a more viable long-term strategy, when contrasted to the traditional engineering structures currently in use. Ecosystems at the land-water interface have developed specific traits in response to environmental constraints and are able to modify habitat conditions by modulating geomorphic processes. .The aim of this study is to estimate vegetation cover and the impact this has on the morphodynamics of sandy beaches at Taiwan Strait. By mapping the interaction between sandy beaches, dunes and vegetation, it is anticipated that patterns of morphodynamics – vegetation on sandy beaches will be classified and used to explore the eco-geomorphologic thresholds within which these systems function. The results from this interdisciplinary study fill a niche in the geomorphology - ecological research area, which could be further used to establish optimum parameters for the establishment of resilient coasts that are capable of adapting to, and coping with future global changes in climate.

沙质海岸是海陆气交界面典型的风—水交互动态地貌类型，并形成了独特的生态系统，是重要的生态带之一（Ecotone）。然而随着经济发展压力和全球气候变化，沙质海岸地貌及其生态服务功能面临着巨大的压力。为减缓沙质海岸地貌侵蚀、保护和修复生态功能，应用植被构建生态防护工程以应对全球变化（Ecosystem-based adaptation, EBA）被认为是易行且可持续的。本研究拟通过对台湾海峡两岸沙质海岸进行完善式跨学科野外调查、大数据收集、分析和计算机模拟，初步实践大数据思维在地貌—生态交叉科学领域中的应用，探索沙质海岸带植被覆盖与地貌动力特征之间的关系，及该关系中可能存在的临界阈值（崩溃临界、可恢复临界）。希望籍此研究完善小至地区大至区域的沙质海岸保护和生态修复理论认识，为探索沿海城市群发展中迫切需要的生态红线划定、 植被带与城建新地理模式提供实际指导意义。

由于台湾海峡的地理、政治特殊性，其地貌和生态研究一直是各界学者关注的焦点。海峡两岸相互独立的基础地貌、生态信息至今尚未得到充分的结合利用；更因为一道海峡，使两岸研究结果不能较好的相互融通。本研究最大化收集整理已公开数据（遥感、地貌、生态等），结合野外调查，建立完整的沙质海岸地貌与植被群落特征信息库，分析不同因子对地貌-植被的影响及指示特征，从而筛选辨识影响地貌-植被的关键指示因子；探索构建海岸沙丘-植被模型，探寻在理想状况与受扰动情况下植被群落对沙质海岸地貌演化的影响。研究发现，虽然大部分研究区域脆弱性指标相近，但导致其脆弱性的因素却有差异。而模拟显示，海岸沙丘尺寸和形态与风沙输入及海浪消散量直接正相关；若植被覆盖率削减为目前一半的程度，则植被增长速率决定了沙滩前丘应对风暴破坏后恢复的能力。本研究构建的指标体系应属目前国内首个海岸沙地评估体系，目的在于适应当地社会、环境、地理特征，使之更具有可操作性和实用性，同时具备较好的敏感度，能及时反映研究区脆弱性差异和变化。再结合模型模拟，希望籍此研究完善小至地区大至区域的沙质海岸保护和修复理论认识，为探索沿海城市群发展中迫切需要的生态红线划定、 植被带与城建新地理模式提供实际指导意义，也为我国海岸线、海岸退缩线以及海岸建设控制线研究和管理提供参考。