太行山干瘠山地土壤厚度空间变异及草灌群落分布特征

在自然条件下,太行山低山区干瘠山地土层浅薄,易形成一定的裸地斑块造成水土流失等灾害,天然林覆盖率低,植被丰富度、物种多样性也受到限制。为探讨土壤厚度与植物群落分布特征的关系,选择太行山低山区干瘠山地东北向和西南向2个坡面,运用地统计学方法研究了土壤厚度的空间变异特征,比较了不同土壤厚度下群落分布、物种多样性和物种丰富度的差异。研究表明:1)东北向和西南向2个坡面的土壤厚度在0—50 cm间,平均厚度分别为11.69 cm和12.77 cm;在0—15 cm的土壤厚度分别占总数的71.43%和62.81%。2)东北向和西南向2坡面土壤厚度呈斑块状分布,但具有显著的空间异质性和强烈的空间相关性,属于中等偏强空间变异,结构性因素是造成土壤厚度空间变异的主导因子。3)所选取坡面的植物主要以草灌为主,共有22科33属38种。土层厚度在10 cm以下时,植物以草本为主;土层厚度在10 cm以上时,植物以灌木为主。其中,土层厚度在10—20 cm时,胡枝子为优势种;土层厚度在20 cm以上时,荆条、酸枣为优势种。4)随着土壤厚度的增加,植物群落组成发生显著变化,在土壤厚度小于15 cm时,物种多样性...

Spatial variability of soil thickness and the distribution characteristics of herb and shrub communities in the arid and barren areas of Taihang Mountains

The soil layer is very thin in the arid and barren areas of Taihang Mountains under natural environment. Bare patches were usually formed and soil erosion and other geological disasters frequently occurred here. The coverage rate of natural forest is low and vegetation richness and species diversity are also limited. In order to explore the relationship between soil thickness and the distribution of plant communities, the spatial variability of soil thickness were studied on the northeast and southwest slopes of the dry and barren mountainous areas of the Taihang Mountains by geostatistical methods. And the differences in community distributions, species diversity, and species richness at different soil thicknesses were compared. The results are as follows:1) the soil thickness was between 0-50 cm, with an average thickness of 11.69 cm and 12.77 cm on the northeast and southwest slopes, respectively. Soil with thicknesses of 0-15 cm accounted for 71.43% and 62.81% respectively on the northeast and southwest slopes of all their soil types. 2) Soil thickness on both slopes showed a patchy distribution but with significant spatial heterogeneity and strong spatial correlation. Moderately strong spatial variation and structural factors were the predominant factors causing the spatial variation of soil thickness. 3) The plants on the studied slopes were mainly herbs and shrubs, and a total of 22 families, 33 genera, and 38 species were present. Where the thickness of the soil layer was below 10 cm, the plants were mainly herbs. Otherwise, the plants were mainly shrubs. Among them, Lespedeza bicolor was the dominant species where the soil layer thickness was 10-20 cm, and Vitex negundo var. heterophylla and Zizyphus jujuba var. spinosus Hu were the dominant species where the soil layer thickness was more than 20 cm. 4) With the increase in soil thickness, plant community composition varied significantly. Where soil thickness was less than 15 cm, species diversity and species richness gradually increased as soil thickness increased, reaching a maximum value where soil thickness was between 10-15 cm. Where soil thickness was greater than 15 cm, species diversity and species richness tended to decrease as soil thickness increased, indicating that soil thickness affects plant diversity and species richness.