[influence Of Index Weights On Land Ecological Security Evaluation In Urban Agglomeration Of Chengdu Plain,china]

Land is the material resource on which mankind depends on for survival and development.Systematic assessment of land ecological security is essential to the development of local area’s society and economy.Because of the complexity of land ecosystems and the differences in regional conditions,there are many uncertainties in decision-making and cognitive attitudes in safety assessment work,and they directly affect the indicators’ empowerment and evaluation results.This paper selects eight prefecture-level cities in the urban agglomeration of Chengdu Plain of Sichuan Province as the research area,and constructs a multi-criteria evaluation system for regional land ecological security from four aspects: natural resources,ecological environment,economic level,and social conditions.The ordered weighted model explores whether the uncertainty of decision attitude and cognition fluctuations has an impact on the stability of land ecological safety assessment results.On this basis,a weight sensitivity analysis is conducted to explore which index weight changes will have an important impact on the evaluation results.The main conclusions of this article include:(1)The volatility of decision makers’ cognition and empowerment attitude toward land ecological security will have a significant impact on the evaluation results and stability of the study area.The evaluation results of land ecological security in the urban agglomeration of Chengdu Plain show that when decision makers and experts weigh in the three different simulation scenarios of "land health","maintaining the status quo" and "sustainable orientation","land health" and "maintaining the status quo“There are 62.5% of the ecological safety assessment levels in the region where the results of the assessment of the ecological safety of the two different attitudes of empowerment have significant differences;and even if the assessment of the weights is relatively small,the “successful orientation”scenario,the ecological security assessment The area where the level differs from the initial level is also as high as 37.5%.(2)The change in the weight of individual indicators did not have a significant effect on the evaluation results of the land ecological security in the study area,and the change in the weight of the full indicator in the indicator system would have a significant effect on the evaluation results and its stability.The evaluation results of land ecological security in the urban agglomeration of Chengdu Plain show that when the weight of a single indicator changes,the weight change range of [-40%,40%] is used as an example.The absolute rate of change did not exceed 3%,and the impact on evaluation results was relatively small.When the index weights in the indicator system changed significantly,the assessment results and their stability changed significantly to "land health" and "sustainable orientation." Compared with the two different simulated actual scenarios,when the weights of all indicators,such as chemical fertilizer application amount and land sewage discharge amount,change,the average weight variation is24.42%,while the evaluation score of the land ecological safety assessment in the study area changes by an average of 10.18%.The district with the smallest change in evaluation results(Deyang city)is experienced a change rate of more than 8%.(3)The method of ordered weighted average and sensitivity analysis can help decision makers and evaluation experts to understand the weight changes in advance,adjust the impact on evaluation results,reduce the uncertainty in the evaluation process,and have important practical significance for practical work and research.The results of the study showed that changes in the weight of indicators such as population density,yield per unit of grain,and annual reduction rate of cultivated land had the most significant influence on the changes in the assessment results.When the population density,grain yield,and annual reduction rate of the index of farmland were simultaneously changed by 40%,research was conducted.The average absolute rate of change(MACR)of evaluation scores in the district reached 8.1%,and even led to changes in the assessment level of land ecological security in some regions(such as Ziyang,Leshan,etc.).Therefore,in actual work,such key indicators should be caused by decision makers,evaluation experts attach great importance.