毛乌素沙地景观的植被与土壤特征空间格局及其相关分析

以毛乌素沙地景观不同尺度和生境中的植被盖度、植物物种数、土壤有机碳和全氮含量的空间格局和相互关系进行了研究。结果表明：不同尺度和生境中的植被盖度与植物物种数之间，以及土壤有机碳含量与全氮含量之间都具有显著的相关。在50－5000m的尺度上，植被盖度与植物物种数之间，以及土壤有机碳含量与全氮含量之间具有相似的空间格局，但植被特征（植被盖度与植物物种数）与土壤特征（土壤有机碳含量与全氮含量）具有不同的空间变化格局，两者之间没有显著的相关关系；在小于50m的尺度上，固定沙丘中的植物物种数与土壤有机碳和全氮含量之间具有显著的正相关，半固定水丘中的植物物种数与土壤有机碳含量具有显著的负相关。这说明，在小于50m的尺度上土壤有机碳和全氮含量格局制约了植被格局，但在50－5000m的尺度上却没有。这一研究表明植被与土壤之间的相互关系依赖于不同的空间尺度。

SPATIAL PATTERN AND CORRELATION OF VEGETATION CHARACTERISTICS AND SOIL PROPERTIES IN THE MU US SANDY DESERT

The relationship between vegetation and soil is central to ecological research. In the Mu Us sandy desert, study of this relationship is required for understanding of landscape ecological processes and restoration of degraded lands. Spatial patterns of vegetation cover, (plant) species richness, soil organic carbon, total nitrogen and their interaction at different spatial scales and habitats in Mu Us are analyzed in this paper. Significant positive correlations between vegetation cover and species richness, and between soil organic carbon and total nitrogen were revealed at all scales and habitats studied. Similar spatial patterns of vegetation cover and species richness and soil organic carbon and total nitrogen were found on scales from 50 to 5000 m. In contrast, no significant correlations between the vegetation and soil characteristics were observed on these scales, implying that soil organic carbon and total nitrogen were not the principal factors. However, on scales less than 50 m the significant positive correlations between species richness and soil organic carbon and total nitrogen contents on fixed dunes, and the significant negative correlation between species richness and soil organic carbon were detected. These results indicate scale dependence in the relationship between vegetation characteristics and soil properties in this environment.