黄河三角洲横向水文结构连结空间尺度变异性分析

Scale effects of structural hydrological connectivity in coast wetlands in the Yellow River Delta

水文连通是影响滨海湿地生态和水文过程的基础要素之一。引入无标度网络模型改进已有横向静态水文连通参数化方法,将其应用于较大尺度(100 hm^(2))量化黄河三角洲滨海湿地的水文连通,并结合已有研究结果分析3个尺度(1 m^(2),100 m^(2)和100 hm^(2))水文连通的空间变异性。研究结果显示,潮间区和生态补水区的水文连通较强,3个尺度的空间变异性主要来自于水文连通指数较高的样点;盐沼区和河滨区相对较弱,空间变异性主要来自于水文连通指数较小的样点,且大尺度水文连通空间变异性相对中尺度和小尺度更高。小尺度和中尺度方法描述了一个样地与周边较小范围的空间区域土壤水分连通状况,在大的潮汐或补水条件下不同区域各个样地倾向于保持一致;而大尺度方法则侧重于描述区域内的水文过程,这是导致尺度差异的根本原因。

Hydrological connectivity is one of the driving factors influence both hydrological and ecological processes in coastal wetlands.In the current study,we used Scale⁃free Network Model to improve the soil water⁃topography based static hydrological index,developed for the point(1 m^(2))and plot scale(100 m^(2)),and parameterized landscape⁃scale(100 hm^(2))hydrological connectivity in four wetland classes in the Yellow River Delta and analyzed the scale effects.Results showed,similar with point and plot scales,the inter⁃tidal flat wetland and artificial reed(Phragmites communis)swamp have relatively stronger hydrological connectivity than tidal marsh and river side wetlands.The hydrological connectivity variation in the landscape scale is higher than which in the other two scales and in areas with higher hydrological connectivity,the spatial variation comes from plots with higher indices and vice versa.The parametrization methods as well as hydrological process heterogeneity are the main reasons for the spatial variation:for point and plot scale,the method focused on the spatial configuration of the soil water content in the target sample and perimeter area which is merely influenced by the tides or other hydrological processes.The landscape method is targeting on the whole study area which is mainly influenced by the hydrological processes.