Construction And Optimization Of Ecological Network In Guizhou Province Based On Ecosystem Health-service Functio

With global climate change and increased human activities,regional landscape fragmentation is increasing,patch connectivity is declining,and the ecological environment is gradually deteriorating.As a typical ecologically fragile area,the ecological environment in karst areas is more sensitive to external interference,and once damaged,it is difficult to recover.In recent years,the construction of ecological networks has been recognized as an important means to enhance the connectivity of habitat patches and carry out ecological protection and restoration of territorial space,which is of great significance for ensuring regional biodiversity and ecological security.However,the understanding and research on how to scientifically construct ecological networks in karst regions are not comprehensive.In order to improve the ecological environment of karst areas in the context of rapid urbanization,this study took Guizhou Province,the karst center of southwest China,as the research area.Based on the evaluation results of ecosystem health and ecosystem service functions,the ecological network of the research area was constructed using morphological spatial analysis(MSPA)methods combined with circuit theory,and the historical change trends of the ecological network in different periods were analyzed and reasonable optimization strategies were proposed,It is expected to provide scientific basis for ecological environment restoration research and sustainable development in karst areas,as well as reference for ecological protection and network planning in other regions.The main research results are as follows:(1)In the past 20 years,the overall accuracy of land use classification has ranged from89.57% to 93.56%,with Kappa coefficients of 0.86-0.91.The accuracy of land use classification is relatively high,which can meet the needs of subsequent research.Among them,forest land and cultivated land are the main land use types,while unused land is the land use type with the smallest floor area.The transfer of land use change mainly occurs between cultivated land,forest land,and grassland.From 2000 to 2020,the area of forest land first increased and then decreased,and the area of grassland first decreased and then increased.The area of cultivated land continues to decrease,while the area of construction land and water area continues to increase,while the area of unused land has not significantly changed.From the perspective of spatial distribution,cultivated land and grassland are mainly distributed in the west of the study area,forest land is mainly distributed in the east and north,and construction land is mainly distributed in central Guizhou.(2)The VORS ecosystem health assessment model based on ecological vitality,ecological organizational power,ecological resilience,and ecological stress can more scientifically evaluate the health level of ecosystems in karst regions.From 2000 to 2020,the comprehensive ecosystem health index of Guizhou Province showed a continuous upward trend over time,with the overall health level rising,the area of sick grade areas continuously decreasing,the area of health grade areas continuously increasing,and the ecological environment significantly improving.From the perspective of spatial distribution,the ecosystem health level in Guizhou Province presents a pattern of low in the west and high in the east,with most regions being above a relatively healthy level.The areas with pathological and unhealthy grades are mainly distributed in Bijie City,Liupanshui City,Qianxinan Buyi and Miao Autonomous Prefecture,Anshun City,and the southern part of Guiyang City;Healthy and relatively healthy regions are mainly distributed in Qiannan Buyi and Miao Autonomous Prefecture,Qiandongnan Miao and Dong Autonomous Prefecture,and Tongren City.(3)From 2000 to 2020,from the perspective of changes in ecosystem services,agricultural production and soil conservation functions significantly increased,while carbon storage and habitat quality showed a trend of first increasing and then decreasing;From the perspective of spatial distribution,the ecological agricultural production of the four ecosystem service functions presents a distribution pattern of high in the west and low in the east,while the carbon storage and habitat quality present a distribution pattern of low in the west and high in the east.The spatial pattern of soil conservation changes from low in the northwest and high in the southeast to low in the middle and middle schools around.The overall level of comprehensive ecosystem service functions in Guizhou Province has a fluctuating trend of rising first and then falling in the past 20 years,with a spatial distribution showing a trend of low among high schools around the country.The level of ecosystem service functions is mainly high and medium.(4)In Guizhou Province,the ecological network has changed significantly in the past 20 years.From the perspective of spatial distribution,the distribution of ecological source patches and ecological corridors is generally uneven,with poor landscape connectivity between the east and west.The ecological source areas are mainly distributed in the northeast and south of the study area,while the ecological corridors are basically distributed in the east;From the perspective of the trend of ecological network changes,the number of ecological sources has a downward trend,but the area has a trend of first rising and then declining,while the number and length of ecological corridors have a downward trend.From the perspective of ecological network structure,the network structure evaluation index showed a trend of first increasing and then decreasing from 2000 to 2020,indicating that the degree of closure,complexity,and connectivity of the ecological network in the study area showed a trend of first increasing and then decreasing.(5)Optimize the ecological network of the research area by increasing ecological sources,adding ecological corridors,protecting ecological pinch points,and dredging ecological obstacles.The optimized ecological network has added 11 ecological source areas and 36 ecological corridors on the basis of 2020.The new ecological source patches and ecological corridors are mainly distributed in the west of the study area,significantly enhancing the landscape connectivity between the east and west;The network structure evaluation index has increased compared to before optimization,and the ecological network structure has been significantly improved.