Ecological Security Assessment And Prediction For Counties

As the basic units to implement the national ecological security strategy,counties have drawn widespread attention,with the development of ecological civilization construction and regional delicacy management.Due to the scarcity of data,especially the environmental pollution information and the lack of a mature ecological security assessment system at county scale,the existing studies still mainly focus on urban and higher scales,which fails to explore the safety features within city.Considering the correlation of ecological security at different scales,the activities of lower-scale ecosystem can also affect that of higher-scale one.Therefore,it is necessary to establish a county-scale ecological security research system,in order to achieve the goal that the ecological security research can be conducted with more detailed and applicable analysis in longer period.Based on the Environmental Kuznets Curve hypothesis(EKC)and the assumption of same model across scales,we first proposed an Environmental Kuznets Downscaling Curve Model(EKCDM).To widen its applicability,we also developed a Scale Model(SM)based on the assumption that the share of a region’s industrial pollutant is equivalent to that of Industrial or the Secondary Industrial output.These two models can be applied to downscale environmental pollution statistics across scales.Considering the positive and negative feedback regulation mechanism within ecosystem,we constructed a ‘Stimulation-State-Feedback’(SSF)framework on the basis of PSR framework.Then a county-scale ecological security evaluation indicator system was built and applied to evaluate the county-level ecosystem’s security of Dongguan city.We adopted the Comprehensive Index Evaluation Model to analyze the dynamic changes and spatial characteristics of ecological security of 32 towns in Dongguan city from 1995 to 2020.Then the Coordination Degree Model was applied to investigate the synergistic level among subsystems of counties.By means of the Obstacle Factor Model,we identified the key factors that restrict these counties’ ecological sustainable development.Finally,the change trend of ecological security for each county was predicted by Autoregressive Integrated Moving Average model.The results are as follows:(1)The proposed EKCDM and SM can achieve downscaling conversion of environmental pollution data at different scales,filling the gap of unavailability to county-level environmental pollution data.They are quite inclusive and can be applied to different environmental pollution indicators in different countries and regions.But these two models are suitable for different economic scenarios.It is suggested to adopt EKCDM when the economic diversity is small between adjacent scales,while SM is suitable for the adverse situations.Therefore,it is necessary to consider the economic factors of the research region and select the more suitable downscaling model and more appropriate type of regression model of EKCDM according to local conditions.(2)From 1995 to 2020,the ecological security of all counties in Dongguan city was at the level of critical safety and relative safety.When it comes to spatial distribution,the security of all counties changed in a patchy manner,deteriorating or improving synchronously from the edge to the middle part.As for the subsystem,the safety evaluation scores of stimulation layer,state layer and feedback layer were low.With regards to the specific index,unreasonable management of land use is the primary factor restricting the stability of ecosystem in Dongguan city,followed by ecological damage caused by industrial pollution.To improve ecological security in Dongguan,it is necessary to make bottom-up breakthroughs,i.e.,from concrete factors(e.g.,second development of land use)to coordination of subsystem and to the whole ecosystem.(3)In 2021-2025,the ecological safety of each county would not change obviously.They would maintain the status quo or improve slightly.But we still need to pay attention to the counties with poor ecological security rank including Guancheng,Nancheng,Dongcheng and Wan Jiang.Concerns are also needed for Qiaotou,Shijie and Chang’an,whose ecological safety would deteriorate during 2021-2025.The newly constructed EKCDM and SM and the county-level ecological safety evaluation and prediction system which integrated ‘data downscaling-security assessment-security prediction’ not only provides a new perspective for accessibility to small-scale environmental pollution data,but also has important implications for the policy making of environmental protection,ecological planning and delicacy management at county scale.