| With the accelerating industrialization and urbanization,the ecosystem health of the Central Yunnan urban agglomeration is facing serious security threats,and there is an urgent need to carry out multi-scale ecosystem health evaluation.Based on this,this study constructs an ecosystem health evaluation index system based on the Vitality-Organizational-Resilience-Service Function(VORS)model for the Central Yunnan urban agglomeration based on five phases of land use data in 2000,2005,2010,2015 and 2020,and evaluates the ecosystem health of Central Yunnan urban agglomeration from administrative scale and ecological scale,respectively.The ecosystem health of the Central Yunnan urban agglomeration was evaluated at the administrative scale and ecological scale,and characterized on maps using Arc GIS software.Finally,a geographic probe was applied to analyze the driving factors affecting the ecosystem health changes and to propose corresponding protection and restoration recommendations for areas with different health levels.The main findings are as follows:(1)During 2000-2020,the area of six land use types in Central Yunnan Urban Cluster changed significantly.Among them,the areas of forest land,grassland and arable land decreased by 291.06km~2,726.67km~2and 517.54km~2,respectively,while the areas of construction land,water area and unused land increased by 1374.23km~2,156.18km~2and 5.22km~2,respectively.the single land use dynamic attitude index of construction land was the largest and reached the maximum value of 8.55%.The composite index of land use degree increases from 0.47%to 6.79%.The largest area transfer of land use types is grassland,of which 1397.23km~2is transformed into arable land and 397.12km~2is transformed into construction land.(2)From 2000 to 2020,the landscape pattern of urban agglomeration in central Yunnan has changed significantly.The patch density index of urban agglomeration in central Yunnan increased from 0.29 to 0.31,Shannon evenness index(SHEI)and Shannon diversity index(SHDI)increased from 0.64 and 1.14 to 0.66 and 1.18,respectively.Contagion index(CONTAG)and aggregation index(AI)decreased by 1.3 and 0.14,respectively,indicating that the connectivity of dominant landscape patch types in the central Yunnan urban agglomeration gradually decreased,and the degree of landscape fragmentation increased.(3)At the administrative scale,the results of ecosystem health assessment of central Yunnan urban agglomeration based on VORS model show that:(1)The index of vitality,organization,resilience and service function decreased gradually from2000 to 2020.In the spatial distribution,vigor and resilience index is low in the east and high in the west,organizational strength index is high in the middle and low around,and service function index is opposite to organizational strength index,which is low in the middle and high around.(2)The comprehensive index of ecosystem health(EHI)values ranged from 20 to 70,and the low EHI values were mainly distributed in the central and eastern regions;Ecosystem health index values are higher in the west and south.(3)In the administrative scale,the ecosystem health of the central Yunnan urban agglomeration was mainly from grade 2 to grade 4,indicating that the ecosystem health of the central Yunnan urban agglomeration was relatively good.The Grade 2 was distributed in the central,northern and eastern parts of the study area,the Grade 4 was mainly concentrated in the southern and southwestern parts of the study area.(4)The number of districts and counties of grade3 accounts for the largest proportion,with an average proportion of 70.22%in 5 years;The number of grade 4 counties increased from 14.3%in 2000 to 18.4%,showing a fluctuating upward trend.(4)At the ecological scale,the results of ecosystem health assessment of urban agglomeration in central Yunnan based on VORS model show that:(1)The index of vigor,organization and resilience decreased gradually from 2000 to 2020,while the index of ecosystem service function remained unchanged.In the spatial distribution,the vigor index and resilience index were low in the east and high in the west,the organization index was low in the north and high in the south,and the service function index was high in middle and low around.(2)The comprehensive index of ecosystem health(EHI)ranged from 20 to 70,and the low value areas of EHI were mainly distributed in the north and northeast;The high value area is mainly distributed in the southern region.(3)The ecosystem health of the central Yunnan urban agglomeration is mainly from grade 2 to grade 4 in the ecological scale,grade 2 is mainly distributed in the northeastern region,and grade 4 is mainly distributed in the central and southern regions of the study area.(4)From 2000 to 2020,the area of grade 3 and grade 4 was larger,showing a fluctuating upward trend.The area of grade 4 reached the highest value of 41.08%in 2020,indicating that the ecosystem health of central Yunnan urban agglomeration is constantly improving.(5)The spatial autocorrelation results showed that the Moran’s I index at the administrative scale of the central Yunnan urban agglomeration from 2000 to 2020was higher than that at the watershed scale,indicating that the spatial clustering of ecosystem health at the administrative scale was higher than that at the watershed scale.The results of cold and hot spot analysis showed that the clustering characteristics of ecosystem health at both administrative scale and watershed scale were manifested in the form of hot spot areas and cold spot areas,and the distribution range of hot spot areas was mainly concentrated in the southwestern part of the study area.However,the distribution of the cold spot areas at the administrative scale and the watershed scale were different.The cold spot areas at the administrative scale are concentrated in the central-eastern part of the study area,while the cold spot areas at the watershed scale are mainly distributed in the northeastern part of the study area.(6)The results of geodetector-based analysis showed that the ecosystem health status of the Central Yunnan urban agglomeration was influenced by factors such as elevation,slope,slope direction,NPP,NDVI,GDP,population density,and land use degree,and the combined degree of land use synthesis,elevation,and slope were all stronger in explaining the health status over the 20-year period.The interaction detection results showed that the contribution of interaction of any two variables was higher than that of single factor. |
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