| The rocky desertification in Southwest China is the manifestation of the degradation of the Karst ecosystem, which seriously restricting the development of regional social economy.Rocky desertification is becoming a tough problem in ecological environment construction in karst areas in southern China. In recent years, many experts and scholars have attached great importance to this problem, and it has been a research hotpot.This paper takes the Guangxi Zhuang Autonomous Region as the research object, in the serious rocky desertification area which is complex, has complete types, and distribute widespread. Through the mathematical model and space operation in GIS, Analyze the rocky desertification of 2004 to 2014 in Karst area of Guangxi and the results are as follows.(1) Proposed comprehensive index of rocky desertification remote sensing classification, and established the classification index system.On the basis of former study on the rocky desertification index, the classification index system for large scale sensing monitoring of rocky desertification.the rocky desertification types of Karst in Guangxi are classified asno rocky desertification, mild rocky desertification,moderate rocky desertification and severe rocky desertification.(2)Proposed the FAC calculate model based on the MODIS data of Guangxi area.Using dimidiate pixel model, the model of vegetation cover(FVC) in Guangxi is constructed, based on vegetation index EVI data.(3)Constructed a spatio-temporal dynamic model algorithm for rocky desertification remote sensing, and analyze the spatio-temporal evolution process of rocky desertification in the study in 2004-2014.Through the calculation of mode, activity, and trend of rocky desertification evolution, it says that the rocky desertification in Guangxi reached 16% of the total area, which accounts for more than 50% of Karst area. The rocky desertification covers by the axis from northeast to southwest, and is more serious in the northwest than in the southeast space. The evolution of rocky desertification involves up to 50% areas during the ten years from 2004 to 2014.However, the overall vegetation coverage increased, the improvement area of rocky desertification is much more than the deterioration area and the rocky desertification has been effectively curbed.(4)In the FRAGSTATS system, selected the landscape index of type level and landscape level, using the landscape space analysis method, the evolution of the spatial pattern of rocky desertification in Karst, Guangxi is analyzed.Analysis of landscape pattern of rocky desertification in 2004, 2009 and 2014,the total number of patches and the total area of rocky desertification decreased, and the occurrence of moderate and severe rocky desertification also decreased. Landscape fragmentation decreased in2005-2014, also says that governance on some minor stone desertification patches has achieved good results. |
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