Forest Resource and Environment Research Center of Guizhou Province, Guizhou University, Guiyang 550025, China.
College of Forestry, Guizhou University, Guiyang 550025, China.
Int J Environ Res Public Health. 2018 Apr 13;15(4):743. doi: 10.3390/ijerph15040743.
Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km², 4.50 km², and 1.87 km², respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.
喀斯特地区是典型的生态脆弱区，石漠化已成为全球该类地区最为严重的生态和经济问题之一，也是灾害和贫困的根源。合理的采样尺度对于喀斯特土壤科学研究具有重要意义。本研究采用基于地理信息系统（GIS）技术和地统计学的网格采样方法，在不同采样尺度下研究了喀斯特地区石漠化特征的空间分布及其影响因素。以侯寨河流域 150 m×150 m 网格采样获得的岩石露头为原始数据，以 300 m×300 m、450 m×450 m、600 m×600 m、750 m×750 m 和 900 m×900 m 5 个网格尺度作为子样集。结果表明，岩石露头在各采样尺度间变化不大，而 5 个子样集的平均值均围绕着整个数据集的平均值波动。随着采样尺度的增加，岩石露头的最大值和平均值逐渐减小，变异性系数逐渐增大。在 150 m×150 m 的采样尺度下，侯寨河流域的轻度石漠化、中度石漠化和重度石漠化面积分别为 7.81 km²、4.50 km²和 1.87 km²。小尺度上石漠化的空间变异性受多种因素的影响，中尺度上的变异性受坡度、岩石含量和岩石露头的共同影响。大尺度上，石漠化的空间变异性主要受土壤厚度和岩石含量的影响。
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