西南喀斯特地区石漠化时空演变过程分析

喀斯特地区石漠化对当地社会经济的可持续发展有严重的阻碍作用,因此,研究喀斯特石漠化时空特征及演变规律,对石漠化治理有着重要的意义。以西南八省为研究区,利用归一化差分植被指数（Normalized Difference Vegetation,NDVI）、净初级生产力（Net Primary Productivity,NPP）、地表反照率（Surface Albedo）和坡度（Slope）数据,借助ArcGIS等软件平台,分析石漠化在不同的坡度、土地利用和生态保护区内的变化。结果显示：（1）轻度和中度石漠化是西南主要的石漠化类型。从空间分布来看,石漠化发生分布面积最广的是贵州,其次为云南和广西。（2）从不同土地利用来看,2000-2015年间无石漠化面积最多,潜在石漠化次之。石漠化主要发生在耕地和林地两种土地类型上,其他用地上石漠化发生面积最少,但是极重度石漠化在其他用地上的发生比例很大,平均在11%左右。（3）从不同坡度来看,石漠化严重程度不随坡度的增加而加剧,在坡度6°-25°之间石漠化发生面积最大。（4）从生态保护区来看,2000和2015年西南喀斯特生态保护区是石漠化面积分布最多的区域,分别为27481.86 km²和21738.65 km²。最少的是大别山山地生态功能保护区,从变化量来看,增加最多的是三峡库区,增加1641.22 km²,减少最多的是西南喀斯特生态功能保护区,减少5743.22 km²。（5）利用NPP、NDVI、地表反照率和坡度能较精准的反演石漠化,其反演权重依次为0.33、0.42、0.15和0.1。研究时段内,西南生态环境逐渐得到改善。

Analysis on the spatio- temporal evolution process of rocky desertification in Southwest Karst area

Rocky desertification in karst areas has a serious impact on the sustainable development of local social economy. Therefore, it is of great significance to study the spatial and temporal characteristics and evolution rules of rocky desertification in karst areas. In this paper, eight provinces in southwest China are taken as research area. Based on Normalized Difference Vegetation (NDVI), Net Primary Productivity (NPP), Surface Albedo and Slope data, and with the help of ArcGIS and other software platforms, the variations of rocky desertification in different slope, land use and ecological protection zones are analyzed. The results showed that: (1) Mild and moderate rocky desertification are main types of rocky desertification in the Southwest.From the spatial perspective, the distribution area of rocky desertification is the widest in Guizhou, followed by Yunnan and Guangxi. (2) From the perspective of different land uses, the area with no rocky desertification from 2000 to 2015 was the largest, followed by potential rocky desertification. Rocky desertification mainly occured in the cultivated land and forest land types,the area of rocky desertification on other lands was the least, but the proportion of extremely severe rocky desertification on other lands was very large with about 11% on average. (3) From the perspective of different slopes,the severity of rocky desertification does not increase with the increase of slope, rocky desertification occurred in the maximum area between slope 6° and 25°. (4) From the perspective of ecological protection areas, karst ecological protection areas in southwest China in 2000 and 2015 were the most widely distributed areas of rocky desertification, covering 27481.86 km² and 21738.65 km² respectively. In terms of variation, the Three Gorges Reservoir area increased the most by 1641.22 km², while the southwest karst ecological function reserve decreased the most by 5743.22 km². (5) Rocky desertification can be accurately inverted by using NPP, NDVI, surface albedo and slope, with the inversion weights of 0.33, 0.42, 0.15 and 0.1 respectively. During the study period, the ecological environment in southwest China was gradually improved.