互花米草盐沼生物地貌状态转换的机理研究

As an important invasive species which has expanded its territory over all coastal provinces of China, the introduction and spread of Spartina alterniflora have significantly impacted the hydrodynamic force, landform, sedimentation and ecosystem of the original mudflat. In order to explore the biogeomorphological mechanisms which affecting the sedimentation rate of tidal flat, and system status transition of biogeomorphological processes over tidal saltmarsh after invasion of Spartina alterniflora, the present project select Rudong Spartina alterniflora salt marsh as research area. .In this project, sedimentation rates will be calculated on 100 sampling stations in Dafeng and Rudong tidal flat to form a data network, and thus to map sedimentation rates over Spartina alterniflora salt marsh. Through analysis of multidimensional data of sedimentation rates, together with correlation analysis of quantitative characterization data of key geomorphic features, sediment dynamic characteristics and biological features, this project will identify main control factors of sedimentation rates distribution, as well as the patterns of biogeomorphological evolution and variation. Data verification will be undertaken at 6 settled stations. Time serials of surface elevations at 6 stations will be derived by several methods to analyze elevation evolution of Spartina alterniflora salt marsh. System status transition will be explored from the changes in tidal flat surface evolution trend and in sedimentation rates. The formation mechanism of sedimentation rate’s characteristic value will be studied. Key factors or indicators of systemic biogeomorphological regime transformation will be identified. Thus, the evolution trend, which is triggered by introduction of Spartina alterniflora, of the new tidal flat depositional system will be shown..The scientific data sets and biogeomorphological mechanisms obtained in this research will contribute to the enrichment of biogeomorphology theory and research methods on Spartina alterniflora saltmarshes, as well as data and theoretical basis for other discipline such as ecosystem research of Spartina alterniflora saltmarshes.

互花米草作为一种人工引种并广泛分布于中国沿海的重要外来物种，对原生滩涂的水动力、地貌、沉积与生态产生了显著影响。为了探明互花米草引种后潮滩生物地貌过程状态转换及机理，本项目在互花米草盐沼分布广泛的如东和大丰潮间带选择100个大面站位用互花米草形态法计算沉积速率，并用有机碳同位素法进行验证，得出如东互花米草盐沼的沉积速率大面分布特征。将两地沉积速率与地貌、沉积动力、生物特征要素相联系，识别沉积速率分布差异的主要控制因素，厘清生物地貌演化和变异的格局。通过6个定点站位的滩面高程时间序列分析，评估互花米草入侵对潮滩高程演化的影响。从滩面演化趋势、沉积速率特征现象的变化入手，分析沉积速率特征值的形成机理，获取系统状态转换的指标与关键参数。揭示互花米草引种后新的潮滩沉积体系的未来演化趋势。本研究有助于丰富互花米草潮滩生物地貌学理论和研究方法，为互花米草生态系统等相关学科研究提供数据与理论基础。

由于海岸防护的需求, 我国1979年引种并推广了互花米草。目前互花米草已遍布中国沿海所有省份，对中国原生沿海滩涂的地貌和生态都产生了重要影响。互花米草作为一种人工引种并广泛分布于中国沿海的重要外来物种，对原生滩涂的水动力、地貌、沉积与生态产生了显著影响。为了探明互花米草引种后潮滩生物地貌过程状态转换及机理，本项目在互花米草盐沼分布广泛的如东潮间带选择 5 组互花米草湿地站位和同高程光滩共 6 组研究站位获取表层沉积物样品、互花米 草地上部分样品和沉积物柱状样。用互花米草形态法计算沉积速率，得出如东互花米草盐沼的沉积速率大面分布特征。并用210Pb测年法进行比对。本项目经过大量野外工作获得的各站位滩面高程、地貌部位、泥质沉积物厚度等地貌特征值与互花米草生物特征值(定居时间、植株高度、单株地上生物量)等一手数据。将沉积速率与地貌、沉积动力、生物特征要素相联系，识别沉积速率分布差异的主要控制因素，厘清生物地貌演化和变异的格局。评估互花米草入侵对潮滩高程演化的影响。从滩面演化趋势、沉积速率特征现象的变化入手，分析沉积速率特征值的形成机理，获取系统状态转换的指标与关键参数。揭示互花米草引种后新的潮滩沉积体系的未来演化趋势。本研究有助于丰富互花米草潮滩生物地貌学理论和研究方法，为互花米草生态系统等相关学科研究提供数据与理论基础。本项研究成果可为海岸带管理提供理论支持和数据支撑。通过沉积速率变化指示的潮滩生物地貌过程状态转换的机理分析，找到在现有生物、地貌、沉积、动力条件下，互花米草湿地土地资源的可持续利用模式。