The Study On The Simulation And Prediction Of The Rocky Desertification In Wenshan Based On The Analysis Of Sensitivity

The rocky desertification in the karst in southwestern China is a manifestation of the extreme degradation of karst ecosystems.It has severely constrained the local economic and social development and the construction of ecological civilization.Therefore,it is very urgent to evaluate and simulate the development trend of rocky desertification in the future.Wenshan is the disaster area of rocky desertification in Yunnan Province with wide distribution,deep-degree,and dangerous.At the same time,in the past,the study of rocky desertification mainly focused on the analysis of distribution characteristics,dynamic evolutionary trends and the driving mechanism.There has been insufficient research on the long-term sequence dynamic evolution based on sensitivity analysis.To make up of the efficiency,we have analyzed the sensitivity of rock desertification factors and conducted a simulation study of rock desertification in Wenshan based on sensitivity analysis.The results are as follows:(1)The concept of rock desertification sensitivity analysis was innovatively introduced,the simulation and prediction of rocky desertification in Wenshan based on sensitivity analysis was focused on,and the study on the development and evolution of the rocky desertification based on the sensitive zoning status of Wenshan and the related national policy on the retreat of cropland to forests and the withdrawal mechanism of nature reserves was deepened.(1)Selecting indicators,such as slope,lithology,distance from fault zone,soil type,vegetation coverage,average rainfall for many years,distance from residential area,distance from road,and type of land use,etc.,the geographically weighted regression(GWR)model was used to discriminate the spatial differentiation characteristics of rocky desertification and impact factors,to optimize indicators and analyze the sensitivity of rock desertification factors.It deepened the important sensitivity factors of the development of rocky desertification within a range of15-25°slope,limestone,distance from fault zone,residential area and road distance within 500m,lime(rock)soil,vegetation coverage 0-0.2,average annual rainfall1202-1350mm,grassland,etc..(2)Sensitivity assessment indicator system for rocky desertification was constructed to establish.Combined with the correlation coefficient and analytic hierarchy process of rocky desertification and impact factors,the weight of each evaluation index was determined,and a multi-factor weighted summation model was used to develop the sensitivity analysis of rock desertification in Wenshan.The results showed that the sensitivity zoning of rock desertification in Wenshan and the spatial distribution of rock desertification grades had high consistency.The field verification also confirmed that the selection of evaluation indexes and the determination of evaluation index weights were all reasonable.(3)Based on the current data of rocky desertification in 2000 and 2008,using the CA-Markov model,the spatial distribution of rocky desertification was simulated in2016.The results showed that the Kappa coefficient reaches 0.7513.The CA-Markov model predicts the rocky desertification of Wenshan has a strong feasibility.Based on the rocky desertification transition probability matrix,taking Wenshan as a single,comprehensive and sensitive zoning condition and the state’s related policy of returning farmland to forests and nature reserves as a constraint condition,an atlas of the suitability of the rocky desertification types will be constructed to carry out the simulation and prediction research of the rocky desertification of Wenshan in 2024.(2)The spatial distribution characteristics of rocky desertification in Wenshan from 2000,2008 to 2016 had been ascertained,and the dynamic evolution of rocky desertification about long-term sequence in Wenshan has been revealed,providing technology support for the prevention and control of rocky desertification in Wenshan.(1)The spatial distribution characteristics of rock desertification sensitivity in Wenshan was summed up.In 2016,the southern,western and central regions were highly sensitive,such as Jiahan County and Renhe Town in Maguan County,Dehou Town in Wenshan City,Xisha Town and Banggu Township in Malipo County,etc.,while the eastern and northern regions were less sensitive,such as the northern part of Funing County and the northern part of Guangnan County.In 2024,the development of rocky desertification in Wenshan will be forecasted.The area of rocky desertification in 2024 is 4,501.39 km~2,with mild rocky desertification.The rocky desertification is mainly distributed in the central and western regions,such as Zhujie Town,Zhulin Town,Babao Town and Heizhiguo Township in Guangnan County,Tiechang Township and Donggan Town in Malipo County,Shede Yi Township in Qiubei County,Jiayi Town in Yanshan County,etc.(2)Under long time sequence,dynamic evolution of rocky desertification in Wenshan was summed up.From 2000,2008 to 2016,the area of rock desertification in Wenshan was reduced and changed significantly,and the dominant rocky desertification type changed from heavy to moderate and mild.The evolution mode was dominated by invariant and single-transformation types.The direction of evolution was mainly from heavy rocky desertification to moderate rocky desertification.From 2016 to 2024,the reduction of mild rocky desertification and the stable area of stony desertification will be the most,while the reduction of severe rocky desertification and the deterioration of rocky desertification will be the least.(3)Based on the analysis of the impact factors of rock desertification,the research results of rock desertification sensitivity zoning and simulation prediction in Wenshan,the prevention and treatment suggestions for the treatment of rock desertification in Wenshan are proposed:(1)Results about the analysis of impact factors and the analysis of sensitivity desertification of rocky desertification are made full use.Rocky desertification prevention work in Wenshan should be deploied hierarchically.Rocky desertification heights and the extremely sensitive areas of Babao Town in Guangnan County and Tiechang Township in Malipo County should respectively pay attention to the factors of land use type,vegetation coverage,and distance from residential areas,etc..It is suggested that the restoration of forests through the closure of mountains and human assistance should be the mainstay of ecological restoration,and appropriate adjustments should be made to the type of land use,and efforts should be made to restore forest vegetation to increase the vegetation coverage in rocky desertification areas.(2)The study attaches great importance to the research results of rocky desertification simulation and prediction based on the analysis of long-term sequence sensitivities,and proposes forward-looking measures to clarify the direction of centralized desertification management.The moderate and severe rock desertification areas in 2024,such as Zhujie Town,Babao Town and Heizhiguo Township in Guangnan County,Shedde Yi Township and Yuezhe Town in Qiubei County,Guichao Town in Funing County,etc.In 2016-2024,rocky desertification area is deteriorated,such as Babao Town,Heizhiguo Township,Jiumo Township and Liancheng Town in Guangnan County,Jiayi Town and Ganhe Yi Township in Yangshan County,Houde Town and Matang Town in Wenshan City,Shupi Yi Township,Nijiao Yi Township and Jinpin Town in Qiubei County,etc..Focusing on the planning and implementation of rocky desertification control project,it laids a solid foundation for improving the ecological environment quality in the karst of Wenshan and even Southwest China.