绿洲-荒漠过渡带景观的植被与土壤特征要素的空间异质性分析

Spatial heterogeneity of vegetation and soil characteristics in oasis-desert ecotone

采用变异函数的理论和方法 ,通过空间异质性特征比较 ,研究了阜康绿洲 荒漠过渡带景观中的植被盖度和土壤环境因子的空间异质性、空间格局及其关系 .在此基础上 ,应用Kriging局部块段插值法 ,以三维图形显示出各个要素的空间分布格局 .结果表明 ,除土壤全盐量空间相关性较弱外 ,其他各要素具有中等程度以上的空间相关性 ,且空间变异主要发生在较小尺度上 .其中 ,植被盖度的空间异质性程度较高 ,在 3km的尺度内具有明显的空间格局 .从空间分布格局看 ,植被盖度、土壤表层含水量和土壤 pH值沿样带相邻点差异对比明显 ,高值区和低值区交错 .草本盖度与土壤表层含水量、土壤 pH间有相关关系 ,灌木平均盖度主要依靠深层次地下水维系 .灌木和草本盖度的块金值具有明显差异 ,可能因为二者要求不同的生态条件 。

The spatial distribution of bio and abiotic factors in ecosystem has the features of spatial heterogeneity in general, and spatial heterogeneity is important in the function and process of ecosystem at a variety of scales. In this paper, semivariance theory and methods were used to study the degree, composition, scale and pattern of spatial heterogeneity of vegetation coverage and soil environment factors, and their relationships in the Fukang oasis desert ecotone of Xinjiang. With block kriging in the studied area of sampling, the spatial pattern of each factor was expressed in three dimensions as well. The results indicated that except the little spatial autocorrelation of salt salinity, there existed a spatial autocorrelation above mean of the other factors, and the spatial variation was mainly limited to smaller scales. The vegetation coverage, for which auto correlated spatial heterogeneity was a main component, had a high degree of spatial heterogeneity with obvious spatial pattern at the scale of 3 km. From the perspective of spatial distributions, there existed a remarkable difference between soil holard and soil pH value in the studied area. Besides this, the higher value areas interleaved with the lower ones, significant positive correlations were observed between herbage coverage and soil factors (surface SH and SPH), and shrub coverage depended on the deep SH. The difference of spatial heterogeneity and pattern between SC and HC indicated the different ecological function and process in the ecosystem.