Study On Early Warning Of Land Ecological Security In Chuzhou City

Land ecological security is one of the core contents of the construction of ecological civilization.The structural stability and functional integrity of the land ecosystem are closely related to the sustainable social and economic development.Therefore,scientific early warning of regional land ecological security is of great significance for the overall coordination of land ecological environment maintenance and high-quality economic development.Chuzhou City is one of the 27 central cities in the Yangtze River Delta.The exploration of its land ecological security status and evolution trend characteristics can lay a solid foundation for Chuzhou to help build a green and beautiful Yangtze River Delta.This study takes Chuzhou City as the research area.Firstly,on the basis of analyzing the research history and related theories of land ecological security early warning at home and abroad,the PSR model and EES theory framework are comprehensively applied to construct the composite evaluation index system of land ecological security early warning in Chuzhou.Secondly,the comprehensive weight of early warning indicators are determined by using coefficient of variation method and entropy method.At the same time,the comprehensive index method and the GM(1,1)model are used to quantitatively calculate and dynamically predict the early warning index of land ecological security in Chuzhou City,so as to study and judge its warning level and change trend.Finally,the obstacle degree model and coupling coordination evaluation model are introduced to further explore the main obstacle factors that limit the improvement of land ecological security warning level in Chuzhou City,and to clarify the internal coupling mechanism of the land ecological security early warning system in Chuzhou City.The main results are as follows:(1)From 2009 to 2019,the comprehensive warning situation of land ecological security in Chuzhou City showed a fluctuating growth trend.The warning degree of Chuzhou city increased from the initial heavy warning level in 2009 to the light warning level in 2019,and the corresponding early warning level rose from level II to level IV.The safety status has experienced three states: risk level,critical level and good level.(2)During the 11-year inspection period,the actual value of the early warning index of land ecological security in Chuzhou City was very close to the predicted value,and both of them showed a steady upward trend as a whole.In 2020,the forecast value of the comprehensive early warning index for land ecological security in Chuzhou is0.8734,which is beginning to change to grade V early warning level,and gradually entering the no-alarm stage.(3)The diagnosis results of obstacle factors show that the obstacle values of the pressure,state,and response subsystem always fluctuate dynamically with the change of time.Among them,the proportion of afforestation area,GDP per capita,forest coverage,investment in fixed assets per land,harmless treatment capacity of domestic waste,the proportion of tertiary industry in GDP,economic density and other early warning indicators have appeared relatively frequently in 11 years,which were the main obstacles to the improvement of land ecological security in Chuzhou.(4)The evaluation results of coupling coordination degree show that the overall value of the coupling degree in Chuzhou City is relatively high and the fluctuation range is relatively small,and a substantial benign resonance coupling has not yet been formed.From the perspective of the evolution trend of the coordination degree,the coordination degree among the three sub-systems of land ecological security early warning in Chuzhou City has shown a steady and increasing upward trend.The value of the coordination degree is between 0.2345 and 0.4861,which mainly covering two coordination levels of moderate imbalance and barely coordination.