基于GIS和RUSLE的滇池流域土壤侵蚀敏感性评价及其空间格局演变

土壤侵蚀是滇池流域重要的生态问题之一,掌握滇池流域土壤侵蚀敏感性的时空变化特征有助于水土保持工作的实施和改进。以降雨量、DEM、土壤类型和Landsat影像为数据源,选择降雨、土壤、坡度坡长、植被覆盖4个因子建立土壤侵蚀敏感性评价体系,对滇池流域进行土壤侵蚀敏感性评价。结果表明:滇池流域土壤侵蚀敏感性以轻度敏感和中度敏感为主。空间分布上,轻度敏感区主要分布在滇池周边。中度敏感区主要分布在滇池流域山地区域,地形陡峭。时间变化上,1999—2014年滇池流域土壤侵蚀敏感程度呈下降趋势。轻度敏感区域面积增加20.18%,中度敏感区域面积减少20.31%,轻度敏感区的增加来源于中度敏感区的转变,转变区域分布于滇池流域西北部和东南部。在土壤侵蚀敏感性影响因子中,降雨是影响滇池流域土壤侵蚀敏感性的关键因子。研究滇池流域土壤敏感性时空变化,识别滇池流域易发生土壤侵蚀的区域,有助于该区域水土保持措施实施、生态治理和土地利用优化。

Sensitivity Assessment of Soil Erosion and Its Spatial Pattern Evolution in Dianchi Lake Basin Based on GIS and RUSLE

Soil erosion is one of the important environmental problems in the Dianchi Lake Basin. It is helpful for the implementation and improvement of water and soil conservation to grasp the temporal and spatial characteristics of soil erosion sensitivity in Dianchi basin. Taking rainfall, DEM, soil type and Landsat Image as data sources, four factors including rainfall, soil, slope length and steepness, and vegetation coverage were selected to establish a soil erosion sensitivity evaluation system which apply to basin, such as Dianchi Lake Basin. The results showed that the sensitivity of soil erosion in Dianchi Lake Basin was mainly mildly and moderately sensitive. In the spatial distribution, the mildly sensitive areas were mainly distributed around Dianchi Lake. The moderately sensitive areas were mainly distributed in the mountainous areas with steep terrain. In terms of the temporal change, the sensitivity of soil erosion in the Dianchi Lake Basin declined during 1999-2014. The area of mildly sensitive areas increased by 20.18%, the area of moderately sensitive areas decreased by 20.31%, and the increase of mildly sensitive areas originated from the transformation of moderately sensitive areas, which were distributed in the northwest and southeast of Dianchi Lake Basin. Among the soil erosion sensitivity impact factors, rainfall was a key factor affecting soil erosion sensitivity in Dianchi Lake Basin. The spatial-temporal changes of soil sensitivity in the Dianchi Lake Basin were studied, and the areas prone to soil erosion in the Dianchi Lake Basin were identified, which contributed to the implementation of soil and water conservation measures, ecological management and land use optimization in this area.