Slope Analysis of Rocky Desertification Based on DEM in Small Catchments as Exemplified by a Homogenous Limestone Region in Guizhou Province

The GIS slope information was developed based on the DEM data.We selected three catchments in different landform areas to analyze the correlation between rocky desertification and slope gradient.The results showed that the rocky desertification areas in these regions are nearly equivalent;rocky desertification becomes serious gradually from plateau to valley.There exist potential ecological deteriorations on the continuous limestone area on the slopes but the slope is not the important limiting factor for ecological restoration.There is a middle peak value in the area ratio of mild and moderate rocky desertification during the slope change from low to high.Mild and moderate rocky desertification focus on 15 to 35 degree slope in the plateau and valley,35 to 45 degree in the slope region.Intense rocky desertifications focus on above 25 degree slope in the plateau and slope region,35 to 45 degree in the valley.The low slope area must pay attention to the rationality of human activities in karst areas.