| Road network is the product of social and economic development,which has greatly promoted the development of human society and economy and information exchange.It is the center of current social and economic development,and its construction and expansion speed was far higher than other construction projects.On the basis of removing the original landscape type,the road construction plays a role in dividing the original landscape,and then has a certain impact on the landscape pattern.Landscape ecological risk is a description of the possibility and degree of harm of the adverse effects caused by the interaction between landscape patterns and ecological processes under the influence of natural or man-made factors at the regional scale.The source of risk mainly comes from the increase of unreasonable man-made landscapes and the reduction of natural landscapes.Human activities change the pattern and composition of the surface ecosystem,which leads to the imbalance of the ecosystem and the increase of ecological risks.The Ruijin-Xingguo-Yudu region is a famous old revolutionary base.The National Development and Reform Commission approved the establishment of the "Ruijin-Xingguo-Yudu Economic Revitalization Pilot Zone" in March 2015.In recent years,the regional economy of Ruixing has developed rapidly,and the speed of road construction has been significantly accelerated.In the past fifteen years,the mileage of highways open to traffic in Ganzhou has increased from 13,319 kilometers in 2003 to 31,008 kilometers in 2018.Ruijin-Xingguo-Yudu regional road network is also rapidly expanding.According to the "2019 Ganzhou Statistical Yearbook",Ruijin-Xingguo-Yudu region has a mileage of 7,021.77 kilometers of open roads by the end of 2018.Such large-scale road construction will inevitably have a certain impact on the regional ecological environment,and the land use and landscape pattern will also change accordingly.Based on the remote sensing interpretation images of Ruijin-Xingguo-Yudu region,this paper obtains the land use data in the study area.Based on this,combined with GIS technology and landscape pattern index,this paper analyzes the impact of road network to land use,landscape pattern and landscape ecological risk in Ruijin-Xingguo-Yudu region from 2003 to 2018.The response of the road network provides a certain reference for the follow-up land management work and ecological civilization construction in RuijinXingguo-Yudu region,and provides basic information for the planning and management of the maintenance of the regional ecological environment construction and the sustainable development of the region,and for the design of landscape functions and landscape dynamics.The main findings are as follows:(1)In Ruijin-Xingguo-Yudu region,forest land and cultivated land are the main types of utilization,and forest land is mainly distributed in areas with higher terrain;cultivated land is concentrated in the northwest,central and southeastern parts.From 2003 to 2018,the overall area of forest land accounted for between 68% and 70%;the area of cultivated land has been shrinking in the past 15 years,the area of construction land has increased year by year,and the grassland and water areas are in a state of fluctuation.The conversion of land use types is mainly manifested in the mutual conversion between forest land and grassland,forest land and cultivated land,and grassland and cultivated land;construction land is mainly transferred from cultivated land in,and water area is transferred out to cultivated land.Principal component analysis shows that the total population,per capita GDP,urban population proportion,and rural residents’ net income are significantly positively correlated with component 1;the proportion of primary industry is significantly negatively correlated with component 1,and the proportion of secondary industry is significantly correlated with component 2 There is a positive correlation,the tertiary industry is negatively correlated with component 2,and the total grain output and animal husbandry output value are positively correlated with component 2.(2)There are a large number of dominant patches in the forest land in the study area.The grassland landscape has a high degree of fragmentation and low dominance,and is greatly disturbed by human activities.In general,from 2003 to 2018,the fragmentation degree of the landscape in Ruijin-Xingguo-Yudu region was slightly reduced,the patch dominance was improved,and the landscape connection degree was reduced;the landscape types in the area were distributed evenly and uniformly.The overall landscape ecological risk in the study area has evolved to a higher level,and the landscape ecological risk has strong spatial heterogeneity.The high-level risk areas are mainly located in the basins of Xingguo and Yudu.Cultivated land is the main land use type,and the low-level risk areas are generally located at higher altitudes,forest land is the dominant land use type.The Moran’I index in the four periods was positive,showing a trend of rising first and then falling.The four indexes passed the significance level test of p=0.01,indicating that the landscape ecological risk in the study area has a positive spatial correlation to a certain extent.From2003 to 2018,there were mainly high-high and low-low clusters in Ruijin-Xingguo-Yudu region,while there were relatively few "heterogeneous points" such as low-high and highlow outlier,and there was little regional difference on the whole.High-high cluster is mainly distributed in the middle and north-central part of the study area;low-low cluster is mainly distributed in the edge of the study area.(3)The overall road density level in Ruijin-Xingguo-Yudu region has improved,especially in the central region;The PD index decreased with the increase of buffer distance,the LPI index and CONATG index increased with the increase of buffer distance,and the SHDI index showed a trend of first increase and then decrease.The overall contribution rate of roads in 2018 was higher than that in 2013.Roads contributed positively to ED,LSI and PD,but negatively contributed to AREA＿MN;The road network has a greater impact on the landscape index of construction land,and less impact on the landscape pattern index of forest land,grassland and water.Geographically weighted regression results show that the landscape ecological risk is negatively correlated with the shortest distance from the center of the sampling area to the road,and positively correlated with road density. |
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