海平面上升对长江河口湿地演替与分布影响研究

Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases. Nature reserve, industries, settlements and societies, especially those in coastal and river flood plains are closely linked with climate-sensitive resources. They have limited adaptive capacities and are more dependent on climate-sensitive resources such as local water and land. The most threatened areas are those with the greatest sensitivity and the lowest adaptability to climate change effects and correspond to low-lying coastal wetlands and estuaries. Yangtze Estuary is extremely vulnerable to climate change, especially accelerated sea-level rise in its low-lying coastal wetlands and estuaries. Sea level rise is one of the most apparent and widespread consequences of climate change. Negative impacts of sea level rise include coastal erosion, periodic or permanent inundation, increased coastal storm flooding and salinisation. These impacts will be non-uniform spatially, since they depend on the magnitude of relative sea-level rise, coastal morphology and human interventions. Sea level rise may increase the damage caused by storms because, with higher mean water level, waves can attack higher on the shore profile and coastal erosion is often accelerated, potentially removing the protection offered by dunes and other protective features.As sea level rises, the long-term sustainability of salt marsh and wetland ecosystem within a relatively narrow portion of the intertidal zone will be changed and this may change total wetland area and consequently total production, depending on local geomorphology and anthropogenic barriers to migration. In this study, we use a variety of data from remote sensing, in situ global positioning system (GPS), tidal gauges, nautical charts, geographic spatial analysis modeling and IPCC sea level rise scenarios to forecast the potential impacts of increased sea level on the costal wetland habitat at Yangtze estuary. The goal is implement research of impacts of climate change on wetland ecosystem and biodiversity, providing measures and technology to mitigate and adapt the adverse impact of climate change, developing information system to effective display and analyses impact of climate change and to enhance response related to climate change.

长江河口湿地是我国长三角区域经济社会发展的重要资源和生态安全屏障。受海平面上升和人类活动双重胁迫，长江河口湿地分布面积减少、生物栖息地丧失、湿地生态服务功能下降，严重威胁到长江河口区海岸防护、水安全与生态安全等。本项研究选择长江河口湿地为研究对象，集成遥感、地面观测与野外调查数据，结合河口湿地区域地形、水文、泥沙、植被、海岸工程、气候等要素，研究长江河口湿地冲淤演变规律及其对海平面上升的响应，辨识海平面上升和人类活动双重胁迫下潮滩湿地与湿地盐沼植被演替机理与格局变化；构建基于过程的海平面上升对长江河口影响评价模型、响应拟合模型与预测评估模型。为该区域应对气候变化、实施河口湿地生态保护、可持续性利用及科学管理提供理论依据和技术支撑作用。

长江河口湿地是我国长三角区域经济社会发展的重要资源和生态安全屏障。受海平面上升和人类活动双重胁迫，长江河口湿地分布面积减少、生物栖息地丧失、湿地生态服务功能下降，严重威胁到长江河口区海岸防护、水安全与生态安全等。.本项研究选择长江河口湿地为研究对象，集成遥感、地面观测与野外调查数据，结合河口湿地区域地形、水文、泥沙、植被、海岸工程、气候等要素，研究长江河口湿地冲淤演变规律及其对海平面上升的响应，辨识海平面上升和人类活动双重胁迫下潮滩湿地与湿地盐沼植被演替机理与格局变化；构建基于过程的海平面上升对长江河口影响评价模型、响应拟合模型与预测评估模型。.研究表明，长江口2017年湿地保有量为468136.66公顷，约702.20万亩，其中自然湿地面积409353.33公顷，约614.03万亩，占全部湿地面积的87.44%。从类型和结构上看，近海与海岸湿地面积减少，相比2012年，总计减少16586.98公顷，减少率为4.29%。主要表现在九段沙外围出现显著侵蚀，浦东南汇、崇明横沙东滩的人工圈围。经遥感分析，1985-2017年，长江口湿地年均围垦面积为2322公顷，围垦强度达到5公顷/年.公里。分析海平面上升和人类活动的多重影响要素，现阶段长江口湿地演变主要受人类活动影响。.依据国家和上海管理目标要求，长江口自然湿地2020年湿地控制保有量不低于613万亩，模型预测表明近期湿地资源总量基本可控，但存在潜在风险，远期具有极大风险。近海与海岸湿地面临减少风险。长江口近海与海岸湿地人为利用强度不断加大，自然淤涨速度减缓，部分区域侵蚀，湿地保护利用动态状态已失衡。草本沼泽湿地处于不稳定状态，远期预期为减少。长江口湿地的未来发展应注重于如何科学实施潮滩湿地修复研究及应用，以及如何科学评估湿地生态状态，提升湿地生态服务功能，为该区域应对气候变化、实施长江河口湿地保护利用动态平衡，科学可持续性利用及管理提供理论依据和技术支撑作用。