Abstract:

In order to obtain spatial distribution and evolution characteristics of rocky desertification,we used topographic position index and distribution index,as well as remote sensing and GIS technologies.Liuzhi special zone of Guizhou province from 1990 to 2010 was taken as an example.Topographic position can be divided into 3 intervals according to elevation and slope:low interval,middle interval,and high interval,and there are 6 levels for rocky desertification:none,potential,slight,moderate,severe,and extra severe.The results indicate that:Firstly,none,potential,slight,and extra severe rocky desertification regions are mainly located in the high interval,whereas moderate and severe rocky desertification regions are mainly located in the middle interval,with none rocky desertification regions in the low interval.Subsequently,the distribution of topographic position interval varied with different causes such as human activities and nature which lead to rocky desertification.Potential,slight,and moderate rocky desertification regions caused by human activities are mainly located in low and middle intervals of topographic position,whereas severe and extra severe rocky desertification regions caused by nature are distributed in high interval.Furthermore,the distribution of rocky desertification is easy to be seen in middle interval of topographic position.Finally,more attention should be paid to low and middle intervals, where the levels are potential,slight,moderate,or severe, whereas natural ecological restoration should be highlighted in the severe and extra severe rocky desertification areas in the high interval driven by natural factors.

Key words: Karst rocky desertification, spatial feature, topographic position index, distribution index, remote sensing data