| With the rapid development of global economy, the road development is becoming more and more fast and extensive. But the rapid development of the road network and expansion cause deep damage to the environment. Road network affects the surrounding ecosystem, and causes environmental pollution, landscape fragmentation and ecological flow blocked, habitat degradation and ecological environmental cumulative effect, etc. With the rapid increase of density of road network,it will have an enormous effect on the landscape and ecological system. Because of the characteristics of road ecological influence, professor Forman said road influence domain accounts for at least 15-20% of the world’s land area. Surrounding environmental ecological accumulation and superposition caused by road construction and operation. Road environment problems caused by the globalization trend of ecology of the sympathetic and earth system itself, it slowly became a global problem. With the growing of human environmental protection consciousness, governments、organizations、experts and scholars are paying more attention to road networks and their influence on the environment. So utilizing the ecology and landscape ecology principles to understand, explore and solve the problem of road network to surrounding ecological environment is necessary.A case study is described on the land use change in Yancheng City,,and effects of road construction on the environment, with remote sensing (RS) and geographical information system (GIS) technology. The cumulative effects model is built through indexs of FCI、CLDI and VCI,combined with the theory of landscape ecology method, habitat evaluation method, the ecosystem service function and value evaluation method with the GIS spatial analysis function and the Fragstats landscape pattern analysis function. Cumulative ecological impact was analyzed on the road network in Yancheng City. Research shows that:(1)Over the past decade, the area of cropland reduced 76919.83 hectares, and 8635.84 hectares into wetland,110147.33 hectares into construction and. Construction land is the second largest land use type in Yancheng City.It increased 117278.00 hectares, which is the main source of cultivated land, the second is the wetland. As an important protection type, wetland reduced 39930.80 hectares, mainly into cultivated land and construction land.(2) Road network stack exists significant correlation with fragmentation, fractal dimension and splitting index. Road density and fragmentation index and splitting index were extremely significant positive correlation,which shows that when the road network density increases, the ecological landscape fragmentation and splitting index has been increased significantly; Road network density is very significant negative correlation with the fractal dimension.When the road network density increases, fractal dimension decreases significantly. From the point of different ecological system, road density and forest land, wetland, farmland, construction land and bare land is extremely significant correlation. The grass land is very significant negative correlation with the fragmentation and fractal dimension.(3) After superposition of road network, forest land, wetland, and the accumulation of farmland ecosystem index were positive. These ecosystems under the influence of the road network are reducing areas,and constantly suffer from more and more negative cumulative effects, especially under the third class roads and the fourth class roads. More intensive road network, negative cumulative effect to the ecological system is more stronger. So the road construction should avoid the protected ecosystem, and protect vegetation out of the cumulative effect. |
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