Susceptibility of Rocky Desertification Based on Analytical Hierarchy Process and Certainty Factor (AHP-CF) Method: A Case from Changshun County, Guizhou Province, SW of China

Rocky desertification induced by Karst is still serious in rocky mountainous region in SW of China although it is mitigated due to endeavor paid by Chinese government. New high technologies such as remote sensing is wildly used to investigate the development of the rock desertification, and some experiences have been reached. However the susceptibility mapping is still in a coarse stage, which largely relies on subjective experiences. A case from Changshun county, Guizhou Province, China is studied. Firstly, the influence factors of rocky desertification are analyzed and weight of each factor is evaluated based on analytical hierarchy process (AHP) method (Saaty 1977). Secondly, a mathematical model based on certainty factor (CF) is established with support of Mapgis, and the susceptibility of the area is assessed. According to natural break rule, the susceptibility is divided into four classes as extremely high, high, medium and low susceptible. The mapping result indicates that low susceptible area only accounts for about 6.61 %, which means most of the area is prone to rocky desertification. The result is verified by the investigation based on remote sensing.