【作者】 陈玉福；

【导师】 董鸣；

【作者基本信息】 中国科学院植物研究所 ， 植物生态学， 2001， 博士

【摘要】 空间异质性的重要性在于其在自然生态系统中的普遍性和它所引起的生态学效应。空间异质性不仅在生态学理论中占有重要位置，而且也是生态系统管理和景观规划等实践中需要解决的基本问题。本文对鄂尔多斯高原（37°38′～40°52′N，106°27′～111°28′E）沙地草地的主要景观单元——沙地和风蚀沙化梁地植被与土壤的空间异质性格局与动态进行了定量的描述和实验研究。 在鄂尔多斯高原沙地景观中，通过对两条相互垂直的5km样线上植被盖度、植物物种数的半方差分析和分形分析，揭示了植被的依赖于空间尺度的自相关特征和等级结构；沙地景观植被结构以小尺度空间变异占优势，植被斑块多集中在5—10m的尺度上。对植被盖度低于20％的流沙斑点或斑块沿样线分布的空隙度分析表明流沙斑点或斑块呈适度聚集的格局。植被盖度和植物物种数与土壤有机碳和全氮含量的空间异质性之间的关系随空间尺度和生境类型的不同而有所不同。对植物群落内风蚀沙化斑块中的植物再生动态和克隆植物沙鞭的克隆生长观测实验表明，克隆植物的存在有利于风蚀沙化斑块的固定，跨越不同斑块边界的克隆植物的生长导致了斑块间的物质能量流动，从而影响了景观空间异质性的动态。 在风蚀沙化梁地中，梁坡处的土壤最为瘠薄，土壤颗粒组成以中细沙为主，这反映了风沙活动在梁坡处形成的沙粒堆积。相应地，梁坡处是以油蒿为优势种的沙生植物群落，与梁顶的典型草原植物（本氏针茅（Stipa bungeana）+百里香（Thymus serpyllum）+冷蒿（Artemisia frigida））群落截然不同。从梁顶到梁底，植物群落受控于较大尺度上的与地形有关的环境梯度。因而其在较大尺度上的空间异质性占优势。更多还原

【Abstract】 Chen, Yufu Directed by Professor Dong, MingThe importance of spatial heterogeneity in ecology lies in its ubiquity as a feature of ecosystems and in the ecological effects it raises. Spatial heterogeneity has an important place in ecological theories. It is a matter that has to be dealt with in the practice of ecosystem managements and landscape planning. In this thesis, patterns and dynamics of the spatial heterogeneity of the vegetation and soil of the main landscape types, including the sandy land and wind-eroded ridge, in Ordos Plateau sandy grassland (37?8’~40?2’N, 106?7’~111?8’E), China, were quantitatively studied by means of field investigation and experiment.In the sandy land, scale-dependent spatial autocorrelations and hierarchical structures were revealed using semivariogram and fractal analysis for the vegetation cover and the number of plant species along the two 5 km transects meeting at right angle. Spatial variations of vegetation structure of the sandy land occurred mainly on fine scales, and most vegetation patches were 5-10 m in diameter. A moderate clumping of mobile sand sites where vegetation covers were less than 20% were discovered using lacunarity analysis. The relation among the vegetation cover, number of plant species, soil organic C and total N contents varied with the spatial scales and the habitats. Field investigations into the regenerations and the clonal growth of the rhizomatous grass Psammochloa villosa in the wind-eroded sandypatches showed that the existence of clonal plants was able to facilitate the stability of the wind-eroded sandy patches, and that the clonal growth of plants across boundaries between patches lead the fluxes of matter and energy between the patches and consequently influence the dynamics of their spatial heterogeneity.In the wind-eroded ridge, the soil was barren and textured with middle- and fine-sands in the mid-slope, reflecting aeolian deposition at the mid-slope due to the wind-transportation activities. Accordingly, a psammophyte community dominated by Artemisia ordosica was found in the mid-slope, which was completely different from the typical steppe plant community (Stipa bungeana + Thymus serpyllum + Artemisia frigida) on the ridge top. The plant community along the hillslope was mainly controlled by environmental gradient associated with topography and therefore dominated by large-scale spatial variance.更多还原