三峡库区(重庆段)石漠化敏感性评价及空间分异特征

SENSITIVITY ASSESSMENT OF KARST ROCKY DESERTIFICATION IN THREE GORGES RESERVOIR AREA OF CHONGQING AND ITS SPATIAL DIFFERENTIATION CHARACTERISTICS

以石漠化敏感性机理为基础,运用GIS与RS技术分别分析了喀斯特岩性因子、地形因子、植被覆盖因子、土壤类型因子的空间格局特征及其对研究区石漠化敏感性的影响程度。在此基础上,基于ArcGIS的空间叠加分析,完成单要素的叠加运算,实现研究区石漠化敏感性的综合评价。探讨了三峡库区(重庆段)这一特殊生态地理区域石漠化敏感性的高低分布规律及其在不同主导因子作用下的石漠化的空间分异特征。结果表明:(1)研究区石漠化敏感区面积为17 376.5km2(37.65%),以高度和极敏感类型为主。(2)空间分布具有明显水平地域差异特征,整体上呈现弧状-条带性分布。东北部和南部最为敏感,中西部基本为不敏感地区。(3)研究区石漠化现状与石漠化敏感性之间有着很好的对应关系,局部地区受人类不合理的干扰活动影响,石漠化现状与石漠化敏感性存在一定的差异。

The rocky desertification has been one of the most serious eco-environmental problem in Three Gorges Reservoir area of Chongqing. The study area is the ecological barrier of the Yangtze River basin and one of the global seventeen key region of protecting the biodiversity. The eco-environment problems in the study area influence not only the security of Three Gorges Reservoir and steady of migrant, but also the ecological security and the socio-economy sustainable development of the Yangtze River basin. So many scholars attach importance to the rocky desertification problems in the study area. The research results improve our understanding about the karst rocky desertification problem. At the same time, these researches have also some shortcomings. Based on the principles of karst rocky desertification, three natural factors affect- ing the sensitivity of karst rocky desertification were chosen as the assessment indices, which were rocky property,slope and vegetation coverage. The assessment map of each factor was finished based on GIS and RS. We also drew integrated assessment map of sensitivity of karst rocky desertification by overlapping function with ArcGIS. Furthermore,we analyzed distribution characteristics and spatial difference of sensitivity of karst rocky desertification in the study area. The results showed that：the area of karst rocky desertifieation was 17 376.5 km2. The strong and extreme sensitivities were the main types of karst rocky desertifieatioin sensitivities. The northeast and the south of study area were the most sensitive area and the west and middle was not sensitive. The real karst rocky desertification accorded with karst rocky desertification sensitivity. The natural factors such as rocky property, topography and vegetation were dominant for rocky desertification,and human activities were the inducements of karst rocky desertification. The vegetation was most affected by human activities. Thus, the conservation and renewal of vegetation is the key to prevent karst rocky desertification.