| Highway is the most important material and energy channel in human life and social development.The expansion of highway network not only brings enormous economic and social benefits,but also aggravates the contradiction among resources,environment and population,which has been neglected.The development of highway network affects the distribution of landscape types and the change of land use types along the highway.It has direct or indirect effects on the ecological process,such as the decline of the value of ecological services,landscape fragmentation,the blockage of ecological chains,and the decline of habitat quality.The cumulative effect of highway construction on the environment and ecology is becoming more and more serious.Taking Fuzhou as the research area,this paper obtains the type maps and road maps of different landscapes in different periods of 2000,2010 and 2017 through remote sensing images,and further uses remote sensing technology,geographic information system and landscape pattern software to get the landscape level and patch type level of highway buffer zone and Fuzhou city,then carries on the comparative analysis,through the analysis of highway to the landscape changes.On this basis,the ecological cumulative effects of the corresponding aspects are analyzed,and a regional road network ecological cumulative effect model with the main contents of ecosystem function deviation cumulative index,landscape structure disturbance cumulative index,vegetation coverage cumulative index and ecological barrier cumulative index is established to analyze the ecological cumulative effects of highway network on Fuzhou region and ecosystems.Influence.By analyzing and evaluating the cumulative effect of highway network on regional and ecosystem,this paper provides a reference for land use,highway and ecological management in this area in the future.Research shows:(1)During the study period,the forest area in Fuzhou was the largest,while shrubs,grasslands,water bodies,gardens and bare land areas decreased to varying degrees.At the same time,the area of forest and construction land in the buffer zonehas increased rapidly.Landscape fragmentation index,diversity index and fractal dimension index in the buffer zone are all higher than the average level of the city,indicating that highway has fragmentation impact on the landscape.In the level of patch type,the fragmentation index of buffer zone is larger than the average level of the whole city,and the aggregation index of Fuzhou city is larger than that of highway buffer zone.The highest value of forest landscape aggregation is due to the large base of forest area,which has a high degree of correlation with landscape types,indicating that highway can cause landscape fragmentation and decrease the value of ecological services.In landscape level,the landscape fragmentation index of highway buffer zone in different periods is much larger than that of Fuzhou City,which indicates that highway construction has a greater impact on landscape fragmentation to a certain extent.The diversity index of highway buffer is larger than that of Fuzhou in the study period,which is the increase and expansion of highway density during the study period.As a result,the dominant patch landscape in the buffer area is divided into dispersed patch landscape types,so the diversity index is low.At the same time,the sub-dimensions of highway buffer zone are much larger than those of Fuzhou in different periods.(2)There is a correlation between highway density and regional landscape index.Highway density is positively correlated with fragmentation and segregation,and negatively correlated with sub-dimensions.In terms of time,landscape fragmentation and segregation increase with the increase of highway network density,while fractal dimension index decreases.Spatially,the change trend of landscape index is obvious when the fourth and third grade highways are superimposed,which indicates that the highway grade has a certain cumulative effect on the regional ecosystem.Highway density overlapped by different highway grades correlated with landscape index of each ecosystem.Landscape fragmentation index of forest,grassland,water body,cultivated land and construction land was positively correlated with highway density,and fractal dimension index was negatively correlated with highway density.Fractal dimension of shrub and garden land was not correlated with highway density,and water separation was correlated with highway density.Degree has no correlation.With the increase of road network density,the fragmentation index and segregationindex of ecosystem increase,while the fractal dimension index decreases.(3)The cumulative effect of highway grade on regional ecosystem is analyzed.The cumulative effect values of three periods from 2000 to 2010,2010 to 2017 and2000 to 2017 are analyzed.The cumulative index of ecosystem function deviation,vegetation coverage index,cumulative index of ecological barrier and cumulative effect index are all positive values after adding different grade highway network in each research period.The positive cumulative effect index indicates that the service value of ecosystem function in Fuzhou is negative cumulative,and the negative effect cumulative increases with the increase of highway network density,and the vegetation coverage index of different highway grades is also increasing,which indicates that there is a negative cumulative effect of highway network on landscape.The regional ecological cumulative effect index is also increasing after superimposing different grades of highway,which indicates that the increase of highway network will bring adverse cumulative effect to the region as a whole,that is,negative cumulative effect on Fuzhou ecosystem.(4)The cumulative impacts of different highway grades on Fuzhou ecosystem are different.From 2000 to 2017,the overall rule is that the cumulative effects of each ecosystem after highway network superimposition show an upward trend with the construction and improvement of highway network.Among them,the ecological cumulative effects of cultivated land,garden land,water body,grassland,shrub and bare land are positive,indicating that the cumulative effects of these ecosystems are negative,while the cumulative effects of construction land ecosystem are negative,indicating that the development of highway has a positive cumulative effect on construction land.In addition,the cumulative impacts of different grades of highways on different ecosystems are also different. |
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