Abstract:
Background At present, numerous scholars have carried out a lot of research and demonstration work in view of Xijiang River Basin of Guangxi Zhuang Autonomous Region duo to its extensive rocky desertification, mainly including scale regional desertification monitoring and rocky desertification formation.But the distribution, the dynamic characteristics and the mechanism of rocky desertification in the whole basin are still lack of effective monitoring.In order to understand the dynamic characteristic of rocky desertification of Xijiang River in Guangxi province at once, GIS and RS technology were used to analyze the status of rocky desertification in Xijiang River Basin.
Methods This study used MODIS NDVI images in 2001, 2006, 2011, and 2016, and auxiliary data, including the map of geology in Guangxi province, land use data, the map of geomorphological and SRTM DEM.The spatial information of rocky desertification and analyzed the dynamic characteristics of rocky desertification in Xijiang River Basin were extracted by GIS and RS technologies.The information of rocky desertification was extracted by the method of human-computer interaction analysis.The Fractional Vegetation Coverage was the grading standard of rocky desertification, which can be divided into slight, moderate and severe.
Results 1) From 2001 to 2016, the area of rocky desertification in the Xijiang River Basin decreased from 18.06% to 7.34%, and the decline was increasing.The decline reason of rocky desertification was related to the treatment of rocky desertification and the migration of population.In addition, levels of rocky desertification structure showed pyramidal shape, the area of rocky desertification decreases with the increase of grade.2) Rocky desertification was concentrated in the central and western regions of Xijiang River Basin, which accounted for 87.72% of the total area of rocky desertification in this area.The reduction rate of rocky desertification in the Guihe River and Zuo River basin increased at the beginning of the studied period, and then decreased.In other sub-basins, the reduction rate of rocky desertification reached the maximum between 2011 and 2016.3) The essence of rocky desertification evolution was a process of the mutual transfer between different levels of rocky desertification, and the low-grade rocky desertification was easily transferred to the adjacent-grade.In this study, rocky desertification was gradually transferred to low-grade.In the areas of serious rocky desertification, the ecological environment has deteriorated and was hard to be restored.On the other hand, areas with serious rocky desertification were usually at the top of the hill, where there was usually no way to reach, thus this increase the difficulty of governance.
Conclusions The dynamic characteristics of rocky desertification in Xijiang River Basin shows that the treatment of rocky desertification of Xijiang River Basin in Guangxi presented positive influence, but the improvement and deterioration of rocky desertification exists simultaneously, therefore, it is necessary to strengthen the monitoring of it and optimize the comprehensive treatment measures of it in the basin.This study may provide references for further strengthening the monitoring of rocky desertification and optimizing control measures of it in Xijiang River Basin.