Ecological Security Assessment And Prediction Based On The Ecological Health-Sensitivity-Risk Framework In Longnan

With rapid global socio-economic development and overexploitation of resources,ecological and environmental problems have emerged,the conflict between human needs and ecosystems has become increasingly acute,and sustainable development has been constrained.How to evaluate the security level of ecosystems and safeguard the material basis for human survival and development has become the focus of current ecological research.Longnan is located in the western region of China,with excellent ecological conditions,complex topography and diverse climate,which is significant for the ecological protection of the upper reaches of the Yangtze River and the Qinghai-Tibet Plateau.In recent years,Longnan has undertaken a series of ecological restoration measures to build an ecological security barrier in the northwest and the country as a whole.However,the complex ecological environment and the backward economic level have limited the assessment of Longnan’s actual ecological level and measures’ effectiveness.Therefore,it is necessary to construct a scientific framework for ecological security assessment and prediction through remote sensing data.This will provide a scientific basis and theoretical foundation for future land planning and ecosystem restoration in Longnan and areas with complex environmental systems but a lack of research information,thus avoiding land use conflicts,optimizing ecological security patterns and maintaining sustainable regional development.This study firstly predicted the future land use status of Longnan in 2030 by using the cellular automata-Markov chain(CA-Markov)model,and analyzed the spatial and temporal dynamics of land use from 2000 to 2030;secondly,based on the definition of ecological security and land use data,a "health-sensitivity-risk" indicator framework was established,and the ecological security status in 2000,2010,2020 and2030 was evaluated by combining the hierarchical analysis,improved entropy method and spatial autocorrelation;finally,the definition of "production-living-ecology" space(PLES)was used to identify land use conflicts.The main conclusions of this study are as follows:(1)Between 2000 and 2030,the land use types in Longnan are mainly forest,cropland and grassland.From 2000 to 2020,influenced by several factors such as climate change,ecological policies and urbanization,water body and built-up land continued to rise,cropland continued to decrease,forest fluctuated and increased,grassland remained almost unchanged after a sudden decrease;the simulation results for 2030 are similar to those for 2020,with only a significant increase in built-up land,suggesting that urbanization will continue.(2)During the study period,the continuous merging and fragmentation expansion of land patches occur simultaneously,and land transfer mainly occurs among grassland,forest and cropland.Land use change was quasi-equilibrium overall from2000-2010 and equilibrium from 2010-2030.Built-up land has the largest and fastest rate of change among land use types,with most of its growth coming from the transfer of cropland and a clear trend towards one-way transfers.(3)The average value of the ecological security index(ESI)in Longnan is 0.547,0.569,0.584 and 0.586 respectively in 2000,2010,2020 and 2030.The overall level of ecological security was gradually increasing,but its rate of increase decreased over time and was expected to largely stagnate between 2020 and 2030.This process was influenced by natural and human factors such as climate change,topographical conditions,ecological engineering,cropland protection policies,urbanization processes,etc.Spatially,the level of ecological security is lower in the northern and central regions,which have a high concentration of human activities,and higher in the southern region,which is mostly forest.The area of stable ecological security has always been dominant between 2000 and 2030,and the area of improvement has been higher than the area of deterioration.(4)Ecological security in Longnan generally had strong global spatial autocorrelation,most significantly in 2000,with its clustering phenomenon first weakening and then strengthening,but relatively stable overall.High-high and low-low clustering areas overlapped highly with areas of high and low ecological security levels,respectively;over time,high-high and low-low clustering areas fluctuated less and tend to become more disordered overall.The study area was predominantly no conflict,with conflicts gradually increasing from the center to the edge of the patch.The conflicts were more intense in cropland than in built-up land,which is related to its adjacent land use types and ecological security level.(5)This study proposes measures to optimize ecological security patterns in three areas: ecological protection,urban construction and agricultural production,such as security network connection,dynamic monitoring and early warning,compact urban development,national forest city construction,intensive land management,three-dimensional ecological agricultural development and ecological migrant compensation,in order to serve as a guide for policy formulation on the optimization of ecological security patterns.