| As a product of urban social and economic development,road network has become one of the main reasons for harming the ecological environment while bringing convenient transportation.Road networks have exacerbated the fragmentation of urban ecological land and the imbalance in landscape connectivity.Their construction projects will greatly destroy the original ecological landscape,affect the connectivity between species’habitats,and hinder the transmission and diffusion of energy information in urban ecology.As a land space with natural attributes to provide ecological services or products,ecological land plays an important role in maintaining landscape ecological balance and alleviating urban ecological bearing pressure.Strengthening the landscape connectivity between ecological land uses is conducive to improving the spatial structure and functional richness of green space,and reducing the energy loss of species across habitats.Therefore,exploring the impact of road networks on ecological land landscape connectivity is of great significance for urban ecological construction and protection.In recent years,the regional economy of Fuzhou has developed rapidly,and the speed of road construction has significantly improved.A comprehensive system of multiple transportation modes such as highway,railway,aviation,and port has initially formed.Such a large-scale road construction has brought many ecological problems,such as vegetation degradation,reduced agricultural area,coastal erosion along the road,etc.,which has also forced relevant scholars to gradually begin to pay attention to its landscape ecological security issues.This paper uses remote sensing image data and road vector data of Fuzhou City as the main data sources,and uses GIS spatial analysis technology to analyze the impact on ecological land from the perspective of spatiotemporal changes in road network characteristics.Based on land dynamics,land transfer matrix,MSPA morphological spatial analysis,connectivity index,and other methods,the spatiotemporal changes in ecological land and its landscape connectivity are studied,and then through road network superposition The analysis of road characteristics reveals its impact on the ecological land landscape connectivity,and proposes optimization plans and strategies for ecological land landscape connectivity in Fuzhou based on the actual situation and research results.The main conclusions are as follows:(1)Fuzhou has a significant increase in road length and road density,with the largest increase in the length of expressways among all levels of roads;In the analysis of road impact areas,forest land is the most advantageous ecological land,and the spatial proportion is constantly increasing;The patch density and landscape shape index of ecological land in the influence areas of highways and provincial roads in various levels of roads have significantly increased,and their landscape fragmentation phenomenon is significant.Among them,the dominant landscape in the influence areas of highways is grassland,while the dominant landscape in the influence areas of provincial roads is woodland;The density of road networks above the intermediate level in Fuzhou has a significant growth trend,with the highest proportion of spatial area increasing by 14.45%.As the road density level increases,the fragmentation of forest land and grassland becomes more serious,and the landscape heterogeneity of various landscape types decreases with the increase of road density,resulting in a gradual simplification of the landscape structure.(2)The ecological land in Fuzhou is mainly forest land;In the relationship of land dynamic transformation,cultivated land is the main source of ecological land transfer,mainly from cultivated land to forest land;The landscape fragmentation phenomenon of forest land in Fuzhou City has weakened,the landscape space tends to be stable,and there are a large number of advantageous patches.The degree of grassland landscape fragmentation is the most obvious,with complex and variable morphological characteristics.The degree of aggregation of water landscape is high,and the degree of dispersion is low;The landscape morphological structure of ecological land in Fuzhou City is dominated by the core area,and the ecological environment quality is relatively good.The conversion relationship is mainly between non ecological land,isolated islands,and the core area,while the area of three types of landscape structures,namely,ring,connecting bridge,and branch,is continuously declining,indicating that although the area of ecological land in Fuzhou City is increasing,the connectivity between patches is gradually weakening.(3)The threshold range for stable landscape connectivity of ecological land in Fuzhou is between 400 and 800 m.The main types of ecological patches in the study area are 10 km~2 giant patches,but the number of patches is mostly small and medium-sized patches,and medium-sized patches have an important impact on the overall ecological land connectivity in Fuzhou City.The overall connectivity level of all districts and counties in Fuzhou City has increased significantly,but the ecological spatial connectivity has decreased in some parts of the period.The changes in regional connectivity are closely related to the urban base,and the closer to the urban core,the more unstable the landscape connectivity becomes.(4)Disturbance in the influence area of the road network led to a significant decline in the Landscape connectivity of ecological land,with a strong threshold area of 800 m.Between 2000 and 2018,with road interference,the area of patches with a"high"degree of importance decreased significantly,while the area of patches with a"low"degree of connectivity increased significantly.The maximum threshold areas of ecological land Landscape connectivity affected by roads in various counties and districts are different.The maximum threshold areas of Fuqing City,Minhou County,Minqing County and Yongtai County affected by roads are 400 m,800 m in Lianjiang County,1200 m in Luoyuan County and Changle District,and 1600 m in downtown Fuzhou.The influence of road networks at all levels on the spatial connectivity of ecological land is in the order of expressway,national road,provincial road and county road.The road network density and Landscape connectivity are highly negatively correlated.During the study period,the level of Landscape connectivity between the road density grades of three to five varies greatly.(5)Based on the establishment of optimization principles and objectives,the optimization scheme of Landscape connectivity of ecological land in Fuzhou is proposed.Taking Fuzhou city center,Luoyuan County,Changle District,and Lianjiang County as examples,the maximum threshold area of Landscape connectivity of ecological land in each district and county based on road network is screened and graded,and the evaluation of Landscape connectivity of ecological land based on the impact threshold area of road network is proposed Four detailed optimization strategies for the connectivity control of ecological land along the road,urban ecological land planning and management,and diversified ecological land layout and management system are proposed to build an urban environment that conforms to the ecological and biological diversity of Fuzhou City,providing scientific theoretical basis and practical guidance for the construction of ecological civilization in Fuzhou City. |
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