| Rocky desertification is a major ecological problem in karst area,which seriously threatens ecological security.Guilin is a typical karst area in Guangxi.Based on the monitoring results of three periods of rocky desertification in 2005,2010 and 2015,this paper analyzed the dynamic changes of rocky desertification land of different land types and different degrees in Guilin in the past ten years on the basis of GPS technology and mathematical model,and studies the dynamic changes of rocky desertification and analyzes the reasons for the changes.And the trend of changes in rocky desertification land area of 2020 and2025was predicted by Markov model in this study,moreover,this study clarified the effect of rocky desertification control of the area,put forward scientific and reasonable suggestions for the effective management of rocky desertification land in Guilin,Guangxi.The main results are as follows:(1)In 2015,the land area of rocky desertification,potential rocky desertification and non rocky desertification in Guilin were 137765.95 hm~2,194220.15 hm~2and 652760.34 hm~2 respectively,which increased by-61732.4hm~2,57361.35 hm~2 and 4371.05 hm~2 compared with 2005.Among them,the area of potential rocky desertification and non rocky desertification land transformed from rocky desertification land is 62128.90 hm~2 and 4312.18 hm~2respectively;the area of potential rocky desertification land transformed into rocky desertification and non rocky desertification land is 3870.70 hm~2 and4467.45 hm~2 respectively;the area of non rocky desertification land transformed into potential rocky desertification and rocky desertification land is 3570.60 hm~2and 837.98 hm~2 respectively.(2)The results of dynamic analysis of karst land in Guilin showed that:in rocky desertification land,the area of grassland and shrubbery decreased,while the area of dry land and woodland increased;in potential rocky desertification land,the area of grassland decreased significantly,while the area of shrubbery increased significantly,and the area of woodland increased by 9.24%;in non rocky desertification land,the area of grassland,shrubbery,dry land and unfinished woodland increased However,construction land and other land increased by 66.56%and 6.26%respectively.(3)The results showed that from 2005 to 2015,the area of light rocky desertification increased by 431.11 hm~2,increased by 6.95%,while the area of moderate,severe and very severe rocky desertification decreased by 29.33%,28.79%and 94.45%respectively.(4)Through correlation analysis and Markov model prediction,it is found that the effect of rocky desertification control in Guilin is remarkable.In the study area,89125.21 hm~2 of rocky desertification succession is in the forward direction,of which 77175.95 hm~2 is caused by forest and grassing measures such as closing hillsides for management,protection,and for afforestation.12998.7 hm~2of rocky desertification succession is in the reverse direction,of which 2337.32 hm~2 and 4453.83 hm~2 are mainly caused by human destruction and natural disasters.In addition,the prediction results of Markov model showed that the area of rocky desertification in different degrees will continue to decrease in 2020 and 2025.It was found that the prediction results are reliable based on the remote sensing data in 2020.Therefore,the area of forward succession is larger than that of reverse succession in the study area,indicating that the rocky desertification situation has been better improved.Conclusion:The rocky desertification in Guilin city of Guangxi decreased in the period of 2005 to 2015 due to the forest and grassing measures significantly promoting the succession of rocky desertification.Based on the analysis of Markov prediction data of rocky desertification in 2020 and 2025and remote sensing data in 2020,it is found that the area of rocky desertification is also decreasing in the future,and the effect of rocky desertification control in this region is remarkable,and the forest and grass measures are an important means to effectively control the Rocky Desertification in Guilin,Guangxi. |
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