| Cities are the places where human beings gather,produce and live,so the urban ecological environment is the most frequently and intensely disturbed place by human activities.With the rapid development of cities,the rise of industry,the development of science and technology,and the increase of population have enhanced the ability of human beings to utilize and transform nature,expanded the living space of human beings,and improved the material living conditions of human beings.Human interference and influence on the urban ecological environment is more and more frequent and strong,but also makes the urban ecological environment problems prominent.City is a sensitive zone and a fragile zone of ecological environment which is easy to be disturbed by human activities.The research on the vulnerability of urban ecological environment has been paid more and more attention by academic circles.Evaluating the vulnerability of urban ecological environment is helpful for us to recognize and understand the degree of vulnerability of ecological environment,identify the key factors that affect the vulnerability of ecological environment,and scientifically choose the best control strategy.It is of great significance to realize the sustainable development of urban ecological environment.Chengdu,located in the west of Sichuan Basin,is an important part of the urbanization strategic pattern of “two horizontal and three vertical” in China,and is one of the core regions in Chengdu-Chongqing area.Surrounded by mountains on all sides,Chengdu belongs to the typical basin topography,which makes the air convection in Chengdu quite unobstructed.With the implementation of the strategy of developing the western region of China,the rapid development of urban economy and the ecological environment problems in Chengdu are becoming more and more prominent.On the basis of summarizing the relevant theoretical and practical studies of domestic and foreign scholars,based on the VSD(Vulnerability Scoping Diagram model and combining the principles and methods of constructing the index system,this paper selects population density from three aspects of “exposure,sensitivity and adaptability”.The proportion of urban construction land,the proportion of industrial output value to GDP,the proportion of green coverage of built areas,the ratio of good air quality days,the proportion of tertiary industry to GDP,the proportion of financial environmental protection expenditure,the proportion of fiscal expenditure on education,Sixteen specific indexes,such as sewage treatment rate,were established to evaluate the vulnerability of urban ecological environment.Taking Chengdu as the evaluation object,the index weight is determined by AHP,and the subordinate grade of ecological environment exposure,sensitivity and adaptability of Chengdu is calculated by fuzzy evaluation method.The comprehensive index method is used to evaluate the ecological environment vulnerability of Chengdu,and the key influencing factors of ecological environment vulnerability in Chengdu are analyzed,and the control strategies of ecological environment in Chengdu are put forward.The main contents and results of the study are as follows:The results of comprehensive index method show that the ecological environment of Chengdu is gradually fragile.Since 2006 to 2015,the vulnerability of ecological environment in Chengdu is generally “low vulnerability”,but the overall vulnerability has been increasing year by year,in 2007 there was a slight decline,the value of comprehensive index in 2007 was the lowest,it was 0.222,and in 2015,the value of comprehensive index was the highest(0.301).The result of fuzzy evaluation shows that the exposure degree of ecological environment in Chengdu is relatively large.The exposure degree of ecological environment in Chengdu from 2006 to 2015 corresponds to the highest membership degree of “higher”,which is 60%.Combined with the results of the composite index method,the exposure index value rose from the lowest value of 0.2184 to the highest value of 0.2978 between 2006 and 2015.It shows that the disturbance frequency and degree of the ecological environment in Chengdu are increasing.The main anthropogenic stress factors leading to the increase of exposure.The sensitivity of ecological environment in Chengdu is in a relatively sensitive state.The sensitivity of ecological environment in Chengdu from 2006 to 2015 corresponds to the most subordinate degree of “medium”,which is 60%.According to the changing trend,the sensitivity of ecological environment in Chengdu is related to the fluctuation of “lower” and “medium” membership degree,but the overall increase of “higher” and “extremely high” membership.Combined with the results of the composite index method,the sensitivity index values showed a downward trend in 2006-2011 and an upward trend in 2011-2014.The lowest sensitivity index value in 2011 was 0.1025,and the highest value in 2014 was 0.1492.This shows that the ecological environment of Chengdu is sensitive to the external disturbance.If the external interference is strengthened,the ecological environment of Chengdu will be more fragile.The result of fuzzy evaluation shows that the adaptability of ecological environment in Chengdu presents a good situation.The adaptability of ecological environment in Chengdu from 2006 to 2015 corresponds to the highest degree of membership of “extremely high”,which is 80%.Combined with the results of the composite index method,the index of adaptability increased from the lowest in 2006 to the highest in 2015 to a maximum of 0.1446.It shows that with the development of social economy in Chengdu,environmental awareness and environmental regulation are increasing. |
PDF Full Text Request