三峡库区奉节到巴东段石漠化分布及驱动因子分析

Distribution of Rock Desertification from Fengjie to Badong in Three Gorges Reservoir Area and Its Influencing Factors

为了解三峡库区石漠化情况,对石漠化进行定量分析奠定基础。以奉节到巴东段为例,通过RS和GIS技术获取石漠化主要影响因子,并利用改进的石漠化增强指数提取石漠化分布图;然后采用决策树C5.0算法获取变量重要性和规则集,科学、合理分析石漠化等级与各个因子之间的关系。研究认为:石漠化的产生不是某种孤立的因素造成的,而是多种因素综合作用所形成的;植被覆盖度是反映岩溶石漠化最直接的表现形态;碳酸盐含量较高的岩性对石漠化影响强烈;距居民区越近对石漠化影响愈强烈;坡度在"35°～90°"发生石漠化概率低,而坡度在"15°～35°"易发生石漠化。

Three Gorges reservoir area is one of the ecologically sensitive areas in China. With the segment from Fengjie to Badong area as a case study, the main influencing factors of rock desertification are collected by remote sensing（RS） and GIS technology. The distribution map of rock desertification is extracted through the improved rock desertification enhance index. Moreover, the decision tree C5.0 algorithm is employed to obtain the impor- tance of variables and rule sets. The relations between rock desertification and various factors are found out. Re- sults show that rock desertification is caused by muhi-factors instead of isolated factor. Vegetation coverage is the most intuitive external expression of rock desertification. High content of carbonate in rock near residential area is more likely to lead to rock desertification. When vegetation coverage is between 0.4 -0.6, with slope of 35° -90° far from residential area, rock desertification is less likely to happen. And when vegetation coverage is low, with slope of 15° -35°and high content of carbonate in the rock near the residential area, rock desertification is highly possible. This research lays foundation for the quantitative analysis of rock desertification.