Identification Of Ecological Restoration Areas And Restoration Strategies In Western Jilin Province

Ecological restoration of territorial space is an important carrier for the realization of ecological civilization and the construction of a beautiful China,and is of great significance to the maintenance of national and regional ecological security.With the goal of enhancing ecosystem service function and maintaining ecological security,promoting ecological protection and restoration from local single-element protection and restoration to regional integrated protection and restoration of mountains,water,forests,fields,lakes,grasses and sands,and realizing comprehensive management and sustainable use of natural resources is one of the important tasks of natural resources management departments in the new era.Ecologically fragile areas are the result of complex and highly dynamic interactions between natural and socio-economic drivers.The delineation of ecological restoration zones is the basis for the ecological restoration of national land space in ecologically fragile areas,and an important means of maintaining regional ecological security and achieving sustainable development.The western region of Jilin Province（43°59′N-46°18′N,121°38′E-126°11′E）is located in the eastern part of the agricultural and pastoral intertwined belt in the north of China,which is a typical ecologically fragile area.Uncertainties in climate change and high-intensity human reclamation have led to thinning of the regional soil layer,decreasing organic matter content,decreasing soil fertility,and worsening ecological degradation.While maintaining the balance of regional ecosystems,there is also the enormous challenge of increasing food production.Exploring the synergistic development path between multiple objectives on the basis of ecological restoration area delineation is an inevitable choice for the sustainable development of ecologically fragile areas.This study is guided by the theory of human-land relationship coordination,landscape ecology theory,sustainable development theory,location theory and ecological security theory.Taking the western region of Jilin Province as the research object,the research idea of the thesis is‘ecosystem service change-service bundles identification-ecological restoration area designation-restoration strategy proposal’.Firstly,a comprehensive assessment of ecosystem services in the study area for the period 2000-2020 was carried out by means of a multi-indicator ecosystem service calculation model.Firstly,a comprehensive assessment of ecosystem services in the study area during 2000-2020 was carried out through a multi-indicator ecosystem service calculation model;ecosystem service bundles were identified at the grid scale and township scale according to the trade-off and synergy analysis between ecosystem services and cluster analysis,and functional zones were divided on the basis of the ecosystem service bundles;ecosystem services and human footprint index were integrated and delineated for the ecological restoration areas of western Jilin Province.Based on the PLUS model,the optimization simulation of land use in the ecological restoration area was carried out through different scenarios to predict the regional ecosystem resilience and the amount of cultivated land resources that can be increased in different scenarios;finally,optimization suggestions for the ecological restoration area in terms of the layout of land use and the enhancement of ecosystem services were put forward.The main findings of the study are set out below:（1）During the period 2000-2020,provisioning services continued to increase in the western part of Jilin Province,and among the regulating services,the functions of carbon fixation and oxygen release and purification of the environment showed an increasing trend in fluctuating changes,while the function of climate regulation continued to decline,and the function of water conservation showed a large inter-annual change due to the influence of rainfall,temperature and other climatic conditions.In supporting services,nutrient cycling showed the same trend of change as carbon sequestration and oxygen release under the influence of synergistic effects among ecosystem services.The overall soil conservation capacity in the western part of Jilin Province is low,with little distribution of high value areas.In terms of maintaining biodiversity,the western part of Jilin Province showed a decreasing trend during the study period.Cultural services showed the least degree of change over the period 2000-2020,with little difference in average levels between years,and all scores between9 and 10.（2）There are significant differences in the ecosystem services of different land use types.Due to the synergistic enhancement effect among ecosystem services,the capacity of cultivated land for carbon sequestration,oxygen release and nutrient cycling tends to increase.Compared with other land use types,cultivated land also has a stronger ability to purify the environment by stagnating dust and absorbing SO₂ in the air.At the same time,cultivated land has a strong recreational function,but cultivated land performs poorly in climate regulation and biodiversity maintenance.Unutilized land is less capable of providing ecosystem services such as environmental purification,climate regulation,soil conservation and habitat quality,but the average level of water conservation in unutilized land is relatively high.Wetlands play an important role in regulating services,supporting services and cultural services,and the scores of carbon sequestration and oxygen release,climate regulation,water conservation,nutrient cycling and cultural services of wetlands are all at a high level.Nature reserves have strong capacity in regulating,supporting and cultural services such as carbon sequestration and oxygen release,climate regulation,water conservation,maintenance of biodiversity and recreation.（3）Identify ecosystem service bundles to delineate functional areas.By comparing the results of K-means clustering and SOFM clustering,the study chose K-means clustering as the classification method of ecosystem service bundles（ESB）at grid scale in the western region of Jilin Province,and named the ESB according to the dominant ecosystem services within the clusters as well as the main land use types.The western region of Jilin Province was divided into ecological conservation bundles,service synergy bundles,water conservation bundles,food production bundles,habitat quality bundles,recreation bundles,and environmental purification bundles.The grid-scale ESB have a higher degree of spatial fragmentation,but the overall distribution of the township scale ecosystem service clusters is obvious.By counting the ratio of major land use types and grid-scale ESB in the township scale ESB,and by combining the clusters that have a high degree of similarity,the western region of Jilin Province is finally divided into three functional zones:the ecological functional zone,the agricultural production functional zone,and the human life functional zone.Compared with the ESB,the functional areas have stronger integrity and spatial connectivity,and there is strong heterogeneity among different functional zones.（4）Ecological restoration zones are delineated by integrating functional zoning,changes in ecosystem services and the footprint of human activities.The functional zones in the western part of Jilin Province have undergone significant changes in area share and spatial location during the period 2000-2020.The ecological functional zones continued to shrink,and the agricultural production functional zones expanded significantly.The results of linear regression analyses showed that ecosystem services in the ecological functional zones had a decreasing trend with the increase of human activities,while ecosystem services in the agricultural production functional areas and human life functional areas had a rising trend with the increase of human activities.Meanwhile,in the spatial autocorrelation results of ecosystem service changes and human activity footprint changes,the areas of low-low concentration and low-high concentration had a large distribution in the ecological functional zones.The study preliminarily divided the ecological functional zone into ecological restoration areas,and in order to ensure the integrity and connectivity of the area,combined with the land use status quo,the final scope of the ecological restoration zone in the western region of Jilin Province was determined to include 56 township units,with an area of 18,044.86km².（5）Land use types within the ecological restoration area changed significantly between2000 and 2020,with cultivated land expanding most significantly,followed by unutilized land and grassland.Unlike the results of geographic detection of ecosystem service drivers,human disturbance factors have a higher degree of influence on land use expansion in the ecological restoration area.By comparing the accuracy of the simulation results between PLUS long time interval and short time interval,it was found that the PLUS model has a very high accuracy of land use simulation in the short time interval.Therefore,three scenarios were set up to simulate the land use pattern in 2025 in the ecological restoration zone:natural development scenario,ecological restoration scenario and ecological-food coordination scenario.The ecological restoration areas were further classified into priority restoration areas,key restoration areas,special restoration areas and general restoration areas,and based on the results of the PLUS model and the current problems in the ecological restoration areas,targeted suggestions and measures to enhance the capacity of ecosystem services such as management of unused land and returning ploughland to grassland were proposed.（6）Nature reserves play an important role in the protection of ecosystem service functions in the western region of Jilin Province.There are a number of nature reserves,nature parks and other protected areas in the ecological restoration area in the western region of Jilin Province,and the results of the PLUS model show that the expansion potential of land with higher ecological value such as grassland,wetland and water bodies in the Momog National Nature Reserve,Xianghai National Nature Reserve and Baolawindu Provincial Nature Reserve in the ecological restoration state has increased significantly compared with that in the natural development state.The study concludes that the western part of Jilin Province should give full play to the advantages of designated nature reserves and prioritize ecological restoration of reserves with problems of cultivated land expansion and wetland degradation.The natural wetlands and water bodies outside the protected areas should be protected,and if necessary,they can be included in the management scope of the nature reserves and protected through policy instruments,so as to play the roles of conserving natural ecosystems,protecting biodiversity,maintaining ecological balance and promoting sustainable development.