| Land is the means of production on which human beings rely for survival and development,the cornerstone of social development,and an importa nt component of the ecological environment system.In recent years,with the co ntinuous improvement of industrialization and urbanization,environmental deterior ation,prominent human-land conflicts,sustainable development is facing severe c hallenges.Therefore,carrying out land ecological security assessment,clarifying t he ecological security status and its evolution law,carrying out scenario simulati on prediction,and formulating corresponding control measures have become the c ritical issues of how to coordinate the relationship between environmental protecti on and economic development.In this paper,Deyang is taken as the research area,combining PSR model,which represents the"human-land relationship",with the"vitality-organization-el asticity-function"theory,which reflects the internal environmental state of the lan d system.Twenty-three factors are selected to construct an evaluation index syste m.The index weight is calculated by the combination weighting method based o n the relative entropy theory.The land ecological security values in 2005,2010and 2015 are obtained by using the comprehensive index method.The time sequ ence change rule under the double scales of grid and administrative region is dis cussed.The spatial evolution and spatial agglomeration characteristics are reveale d by using the change map method and ESDA spatial exploration analysis metho d.In IDRISI software platform,the suitability map of spatial distribution of lan d ecological security level is established through comprehensive multi-criteria eval uation model.CA-Markov model carries out multi-scenario simulation prediction of 2020 land ecological security level"maintaining the status quo","giving pri ority to economic development"and"giving priority to ecological environment protection",and carries out multi-scenario state fitting based on the actual situati on and planning of the research area to obtain the"comprehensive"spatial patte rn.In order to improve the level of land ecological security as the goal,to disti nguish the types of land ecological security control areas,and to develop solutio ns.The main contents and conclusions are as follows:(1)The overall level of land ecological security in Deyang is good,showi ng a downward trend of fluctuation,with significant temporal and spatial evoluti on characteristics.From 2005 to 2015,the annual average value of land ecologi cal security in the whole city is greater than 0.5,which is in a good state,but with fluctuation and decline trend.The spatial distribution presents a"concentri c circle"shape with"low center and high east and west"decreasing from the c entral area to the peripheral areas.The pattern types are mainly stable and earl y-stage variation,accounting for 78.773%of the total area.The late-stage variati on is not significant and the level is relatively stable.The spatial distribution of grades has strong positive correlation,but the correlation gradually weakens with t he passage of time.From the perspective of local spatial autocorrelation,the H-H and L-L concentration areas are the main types of correlation.The former is mainly distributed in the mountainous areas in the northwest and hilly areas inth e southwest,while the latter is mainly distributed in the central urban area,and the range gradually decreases from south to north.(2)The results of different scenarios of land ecological security level base d on different simulation rules have significant differences.The fitted"comprehe nsive"spatial pattern can better reflect the organic combination of economic deve lopment,environmental protection and policy planning.The scenario of"maintain ing the status quo"follows the law of natural change between levels,with good,safe and critical levels as the main ones in 2020.The"economic development priority"scenario focuses on economic development,and the overall level of lan d ecological security has declined.In 2020,the area of safety level has decrease d by 597.660km~2 compared with 2015.The areas of sensitive level and severe le vel have increased significantly,with 297.132km~2 and 202.045km~2;The"ecologi cal environment protection priority"scenario focuses on environmental restoration,and the overall level of land ecological security has risen.In 2020,the safe area has increased by 429.559km~2 compared with 2015,while the bad area has decrea sed to 119.456km~2;The"comprehensive"scenario is a combination of natural l aws and coordinated development of ecological economy,which to a certain exte nt provides the best choice for decision makers.The overall safety level in 2020is better,but it is lower than that in 2015.The areas of safety level and good l evel are reduced by 190.414km~2 and 19.450km~2 respectively,and the areas of cri tical level,sensitive level and bad level are increased by 14.623km~2,69.908km~2and 125.333km~2 respectively.(3)According to the different land ecological security control areas,ecolog ical protection strategies and measures such as"key treatment"and"treatment+monitoring"are advanced respectively.The first-level district adopts the"monito ring"mode,which can make steady progress,strengthen ecological compensation,develop ecological agricultural tourism and promote economic development.These cond-level district adopts the mode of"prevention+monitoring",moderate manag ement,strengthening ecological monitoring and improving vegetation coverage;The third-level district adopts the"governance+monitoring"mode,continuously mana ges,adheres to scientific planning,implements strong farmland protection measur es,stabilizes quantity and improves quality;The fourth-level district adopts the"key management"mode,strictly controls the scale of construction land,increases t he layout of ecological land,adjusts the industrial structure,and explores a new road to industrialization. |
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