| Located in the southwestern part of Kunming,the capital of Yunnan Province,China,Dianchi Lake is the largest plateau freshwater lake in Yunnan Province and the sixth largest freshwater lake in China.The drainage area covers an area of 2,920 square kilometers.Dianchi Lake has many functions such as water supply,climate regulation,urban ecological balance and land use.In the late 1980s,due to the combined effects of various disturbances in the history,the water quality of Dianchi Lake dropped sharply.The water quality of the whole lake was inferior to the class V.Dianchi Lake was listed as one of the "Three Rivers and Three Lakes"for national key pollution prevention and control.With the emergence of pollution,the social-ecological system of Dianchi Lake has undergone a regime shift,which has led to changes in many key factors.The sustainable development of the Dianchi Lake Basin has a dilemma:the development of Kunming requires Dianchi Lake to provide the necessary ecological services,but Dianchi Lake cannot provide corresponding services because of ecosystem damage.When people try to repair their ecosystems,the results are minimal.This study examines the process of social ecosystem changes in Dianchi Lake from the perspective of elasticity theory,and analyzes the relationship between the ecological environment changes and human activities in Dianchi Lake and the main disturbance factors and changes of social ecosystem changes.Through multidisciplinary research methods,research on the changes in key factors including water quality,climate,aquatic plants,and social systems including economic,policy,and land use in the Dianchi ecosystem,and find out the interrelationship among key factors.Establish an adaptive cycle model of the social ecosystem of Dianchi Lake,and analyze the contradiction that will be faced in maintaining the social ecosystem flexibility of Dianchi Lake.Then,we analyzed the advantages and disadvantages of Dianchi Lake’s natural resource management,and proposed to construct the flexible management of Dianchi social ecosystem.Policy recommendations.Following the above research ideas,the following conclusions were obtained:1.The problem of pollution in Dianchi Lake is both a natural issue and a social issue.When solving the dilemma of Dianchi development,we are relying on the advancement of science and technology,and also require changes at the social level.From the point of view of the theory of elasticity,after the situational transformation of Dianchi Lake,the system is difficult to return to the previous situation in a short time,so the pollution control work in Dianchi Lake has to go through a long and arduous journey.2.Dianchi Lake is a large-scale Social-ecological system.The complexity of social systems and ecosystems in the system is highlighted.The Social-ecological system composed of interactions is more complicated.In this highly complex system,any Changes in the characteristics of the system are bound to affect another system.The four parts of the Social-ecological system,resource unit,management system and users in the Social-ecological system of Dianchi Lake are linked to the feedback through the role of social systems and ecosystems.Among them,the most significant impact on the Social-ecological system of Dianchi Lake is the pollution pattern in the ecological measurement.The changes and development of the Social-ecological system of Dianchi Lake are carried out around this main line.3.By correlation analysis,principal component analysis and regression analysis of the key factors of the Social-ecological system of Dianchi Lake,it can be seen that due to different management methods,the correlation between the variables of Caohai of Dianchi Lake and the outer part is different,but two Social economic variables,artificial facility variables,and system interaction variables are strongly correlated in each region.It is worth noting that the impact of climate change is relatively small when the social development of the basin brings more sustained pressure on the Dianchi Lake water body.From the principal component analysis,the system consists of economic development index,water quality change index and water level change index.From the results of regression analysis combined with Social-ecological system theory and resilience theory,it is believed that the Social-ecological system of Dianchi Lake has the characteristics of complex systems such as nonlinearity and unpredictability.4.According to the adaptive cycle model,the development process of Dianchi Lake has gone through five stages,namely the first stage(1949-1952)is a restructuring stage.The second stage(1953-1965)belongs to the rapid growth stage.The third stage(1966-1989)is a stable and conservation phase.The fourth stage(1990-2000)is the release-reorganization stage(Ω-α stage).Nowadays it belongs to the reorganization-fast growth stage.This is the period in which the system re-accumulates various elements.Each element has the potential to determine the future direction of the system,which means that Dianchi Lake faces new opportunities and challenges.If grasping the system characteristics of this period,and adapting through natural resource management,we can enhance the flexibility of the Social-ecological system of Dianchi Lake to achieve sustainable development.5.The transformation of the Dianchi Lake ecosystem has led to the transformation of the Social-ecological system.The reason is that the system is affected by continuous disturbances and accidental disturbances.The lake volume shrinkage,population growth,economic development,land use and the development of surrounding industrial and agricultural are all persistent negative impact disturbances.The promulgation of protection regulations,Dianchi Lake treatment projects,and the development of Dianchi Lake scientific research are persistent positive impact disturbances.The construction of land around the lake,the introduction of exotic fish species,the construction of breakwaters,and the loss of traditional knowledge are the negative accidental disturbance of the impacts.The completion of the sewage treatment plant,the rectification of the river channel and the river manager system,and the development of the"Four Retreats and Three Returnings"belong to the positive accidental disturbance of the impacts.The Xiyuan tunnel dividing the Dianchi Lake,the large-scale water transfer project,and the artificially adjusted water level belong to the influences which cannot be determined.6.Research on the changes in the service functions of the Social-ecological system of Dianchi Lake,it found that the most demanding service functions in the Dianchi Lake Basin today are land use and tourism landscape.Geographic information system research indicates that the land use situation in Dianchi Lake Basin is transferred from farmland,forest and bare land to construction land.Combined with the investment changes of Kunming real estate,it is believed that the biggest contradiction in the sustainable development of DianchiLake Social-ecological system will be the choice of land use mode.7.Case-studies show that Dianchi’s natural resource management still lacks attention to diversity and redundancy.The depth and breadth of participation of stakeholders and NGOs is insufficient.The functions of management institutions are duplication.Problems,such as the lack of complexity in management and the loss of traditional knowledge in the region,are shown.The flexible natural resource management of Dianchi Lake should be carried out in seven aspects:diversity and redundancy,management of connectivity,slow variable management,cultivating complex system thinking,combining modern science and traditional knowledge,encouraging broad participation,and establishing a diverse management system.8.Based on the above analysis,the research shows that the sustainable development of Dianchi Lake will face several problems,such as poor management of natural resources,rapid socio－economic development of the river basin,uncoordinated demand for ecological protection,and overloading of land and water resources.Improving management models to enhance social ecosystem resilience is the key to solving these problems..At the same time,the following the enlightenment from the theory of elasticity to the pollution control of Dianchi Lake:(1)From the perspective of complex system theory,we should establish a more comprehensive appraisal system in addition to the main line of water quality assessment.(2)From the perspective of adaptive management,the management system of Dianchi Lake should be fully incorporated into stakeholders.(3)In the process of the pollution control,we should fully understand the complex characteristics of"non-linear"and"unpredictable"of social ecosystems,and carefully manage and improve large-scale projects around Dianchi Lake. |
