基于遥感和空间分析的潮间带生物地貌系统稳态转换理论实证与预测研究

The degradation of coastal wetlands is a global environment problem under the influence of climate change and extensive human activities. The understanding and prediction of the shifts between vegetated marshes and bare mudflats is of great importance for ecosystem management and restoration, considering the ecosystem services provided by tidal marsh ecosystems. Vegetated marshes and bare mudflats have been suggested to be alternative stable states in intertidal ecosystems. However, the empirical evidences for the theory and the prediction study of state shifts between vegetated marshes and bare flats are very limited. This project aims to test the hypothesis empirically and to predict the location of state shifts between bare intertidal flats and vegetated marshes based on remote sensing and GIS. Several empirical evidences are tested such as clear boundary, bimodal distribution, abrupt shift, threshold behavior and hysteresis effect. The mechanism causing alternative stable sates, i.e., the biogeomorphic feedbacks, are also tested by studying the spatial relationship between elevation, biomass, sediment deposition, currents and waves. Models are built based on the thresholds of single factors and the multivariate statistics to predict the shifts between vegetated marshes and bare flats, and validated with data from different period or different location. This study is an interdiscipline research combining the theory and methods of geomorphology, ecology, remote sensing and GIS to improve the understanding and prediction of the shift between vegetated marshes and bare flats, which is of important scientific significance and practical value. This study may serve as a scientific basis for the management and restoration of tidal marshes and their important ecosystem services.

在全球气候变化和人类活动影响下，滨海湿地退化已成为全球性问题。由于湿地植被具有重要的服务价值，研究其与光滩之间的转化机理，实现对二者间转化的预测，对可持续管理和保护滨海湿地具有重要意义。已有研究指出上述转化可能是多稳态之间的转换，然而相关的实证研究十分有限。本项目旨在基于多时相遥感和GIS空间分析技术，证明现实中潮间带生物地貌系统中多稳态的存在，并应用该理论构建模型，对植被和光滩之间转化的空间格局进行预测。本项目将通过检验双峰分布等判断依据验证多稳态在潮间带的存在；通过研究高程、植被生物量等变量空间格局的相互关系验证生物地貌反馈作用并建立概念模型；基于单因子阈值和多元统计建模，对植被和光滩之间转化的空间格局进行预测。该研究顺应多学科交叉发展的趋势，将地貌、生态和遥感GIS的概念方法充分结合起来加深对潮间带植被与光滩之间转化的认识，为滨海湿地的保护提供依据，具有重要的科学价值和应用价值。

在全球气候变化和人类活动影响下，滨海湿地退化已成为全球性问题。由于湿地植被具有重要的服务价值，研究其与光滩之间的转化机理，实现对二者间转化的预测，对可持续管理和保护滨海湿地具有重要意义。.本项目基于多时相遥感和GIS空间分析技术，验证滨海湿地生物地貌系统中多稳态的存在，研究潮间带多稳态概念模型与产生机制，构建模型对植被和光滩之间转化的空间格局进行预测，并针对辽河口潮间带等区域进行了遥感与空间分析。.本项目研究发现：开始均匀分布的植被在水流冲刷干扰后会产生具有清晰边界的植被区和光滩区，并且其整体植被生物量呈现双峰态分布，标志着植被态和光滩态两种稳态存在的可能性。水流冲刷干扰形成了河床和沙洲的地貌格局，对植被态、光滩态的分化产生具有促进作用。在不同强度的水流冲刷干扰下，植被能否存活并生长存在不同的阈值；在不同的植被生长状态下，可抗击水流冲刷的强度也存在不同的阈值。生物地貌反馈作用是产生潮间带多稳态的主要原因，基于此建立了潮间带多稳态的概念模型。先锋植被斑块作为潮间带生态系统从光滩态向植被态转换的重要标志，可以对其周边的水动力条件和沉积条件产生重要影响。基于高程、潮流、风浪等因子建立了多元统计模型，可以实现潮间带生物地貌系统稳态转换时空格局的预测。针对辽河口潮间带等区域，构建了翅碱蓬植被指数（SSVI），可有效用于翅碱蓬识别与提取并监测其时空变化。构建了小尺度潮间带生态系统遥感综合评估方法，能够定量反映研究区各地物类型的生态系统时空差异。构建了海域使用景观格局评价指标，能较好地揭示海域使用景观格局特征。开展了海岸承载力监测与评价，可以客观的反映海岸线开发承载力。研究了水色异常遥感提取及动态监测方法，对破坏潮间带生态系统稳定性的藻华灾害进行预警预测具有重要意义。.该研究充分结合地貌、生态、遥感、GIS等学科领域，丰富了植被与光滩之间转化的认识，为滨海湿地的保护提供依据，具有重要的科学价值和应用价值。