Evolution features of rocky desertification and influence factors in karst areas of southwest China in the 21st century

This work is based on the analysis of both remote sense results of rocky desertification area and the relative statistics data.The purpose is to reveal the temporal and spatial evolution features and the influence factors of rocky desertification in karst areas of southwest China in the 21st century.The total area of rocky desertification in karst areas of southwest China decreased to 920,000 km2 in 2015 from 1,135,000 km2 in 2000.Therefore,the general tendency of rocky desertification in karst areas of southwest China is gradual decline,while it was increase from 1989 to 1999 before the 21st century.Moreover,the rocky desertification degree in karst areas of southwest China is getting lighter,which changed from the heavy and middle ones in the early 21st century into the light and middle ones in 2015.Ratio of the serious heavy rocky desertification was 38.08% in 2000,and decreased to 15.31% in 2015,which shows that the tendency of rocky desertification in karst areas has been suppressed effectively.However,the rocky desertification evolution has a large regional difference and a close relationship with the vegetation rehabilitation strength,karst landform classifications,exploitation of ground water resources,rainfall distribution and poverty degree of the local people.The vegetation rehabilitation plan area has a positive relation with the decreased area of rocky desertification.There are better treatment effects of rocky desertification in the peak forest plain and the solution hill depression due to their relatively good ecological and economic conditions.The exploitation of karst groundwater resources can promote the forestation effects,while vegetation naturally restored more quickly in the regions with abundant rainfall.And the poverty of local people may lead to increase of the rocky desertification area.