| With the development of industrialization and urbanization,the rapid expansion of urban,the expansion of the population,unreasonable development and utilization of natural resources,the contradiction of population,resources and environment is growing.Unreasonable human production and living activities lead to the gradually deterioration of ecological environment and frequently natural disasters in many important ecological fragile area,important ecological area and ecologically sensitive area,the fundamental reason is that the way of land use is unreasonable?Therefore,this paper is based on the ecological security of the Three Gorges Reservoir area,which is the China's important ecological strategy protection area,and also the ecological fragile area and the ecological sensitive area.Taking the Jiangjin area in the Three Gorges Reservoir Area as the research area,Based on the natural environment,regional social and economic status,the present situation of land use and ecological environment condition,through two aspects of the importance of ecosystem services and ecological sensitivity,evaluating land ecological safety of Jiangjin District,using the results of the land ecological security evaluation and the minimum cumulative resistance model,constructing ecological security pattern in Jiangjin District.It provides a reference for the ecological protection and the urban expansion in Jiangjin District,and the ecological protection and the construction of the ecological security pattern in the Three Gorges Reservoir area.Through the study,the results are as follows:(1)The ecological sensitivity of Jiangjin region is mainly moderate sensitivity and mild sensitivity.Moderate sensitivity and mild sensitive area account for 34.45%and 25.76%of the total area of the study area,the distribution is scattered,and is mainly fragmentized,distributing in the whole study area.The highly sensitivity is mainly distributed in the southern mountainous area,accounting for 21.57%of the total area of the study area,and the distribution is more obvious.These areas are mainly mountainous and woodland.Insensitive and most sensitive distribution area is less in the whole area,accounting for 11.20%and 7.02%,insensitive is mainly distributed in the south central region,the distribution of most sensitivity is remarkable,mainly for the strip,such as distributed along the Yangtze River,along the mountain zonal distribution,there is the feature of geographical space in the ecological sensitivity of the study area.(2)The ecosystem service value is showing that the northern is low and the southern is high in Jiangjin District.The most high value area is mainly distributed in the northern part of Jiangjin District,such as the Yangtze River,accounting for 4.52%;The high value area is mainly distributed in the Jinyun mountain,Zhongliang mountain,Tongluo mountain,and the southern part of Jiangjin,with an area of 1272.72km~2,and the proportion is 39.55%;The medium value area is 1447.13km~2,accounting for44.97%,the area of nearly half of the Jiangjin area,but the distribution is scattered,mainly distributing in the central part of Jiangjin district.The reason is that the cultivated land and garden area are widely distributed here;Low value is mainly distributed in the Degan street,Jijiang street and Baisha town which are along the Yangtze River,in addition,Shuangfu street and Luohuang town that are close to Jiulongpo District where there are a lot of low value level,and the other is scattered in the area,low value area is 339.18km~2,accounting for 10.54%;extremely low value area is 13.19km~2,accounting for 0.41%of Jiangjin District,without obvious distribution in the study area.(3)In the evaluation results of land ecological security in Jiangjin District,the total area of the unsafe area and the mild unsafe area occupy 55.84%of the total area of the Jiangjin area,which account for more than half of the total area of the Jiangjin District,indicating that the land ecological safety in Jiangjin district is below the general safety level.Extremely safe area is 133.48km~2,accounting for 4.15%of the Jiangjin District,mainly distributing in the Yangtze River and its tributaries;safer area is 929.63km~2,accounting for 28.89%of the Jiangjin District,mainly distributing in Jinyun mountain,Zhongliang mountain,Tongluo mountain,Yunwu mountain,Simian Nature Reserve,Gunziping Forest Park,Heishanshi Forest Park and other areas;The medium safe area is 357.92km~2,accounting for 11.12%of the Jiangjin District;mild safe area is 1485.56km~2 and it is the largest area;mild safe area and medium safe area interlaced distribute in the north and central regions in Jiangjin District,this due to that cultivated land and garden land are closely related to the wildly distribution;unsafe area is 311.42km~2,accounting for 9.68%in Jiangjin District,mainly distributing in the Degan street,Jijiang street and Baisha town which are along the Yangtze River,besides,the distribution of the north of Shuangfu Street and Luohuang town close to the Jiulongpo District is a large area.(4)Constructing the ecological security pattern in Jiangjin District.By determining the ecological sources and urban land source,using the minimum cumulative resistance model,constructing the ecological sources of expansion resistance factor evaluation system and urban land use expansion resistance factor evaluation system,and then,establishing ecological source expansion minimum cumulative resistance surface and urban land use expansion minimum cumulative resistance surface,according to the ecological source expansion of the minimum cumulative resistance surface the urban sprawl and the minimum cumulative resistance determination of resistance difference between surface,so as to determining the ecological security pattern of high medium low area.The important ecological corridors,radiation channels and ecological strategic nodes of the region are identified through the shortest path and hydrologic analysis.The low ecological security pattern in Jiangjin District is 994.71km~2,accounting for 30.98%;medium ecological security pattern area is 297.90km~2,accounting for 9.28%;high ecological security pattern area is 759.68km~2,accounting for 23.66%;other area is 1158.86km~2,accounting for 36.08%;identifying 38important regional ecological corridors and 14 ecological strategies.Finally,from the three aspects of the planning of land use and the formulation of urban and rural,construction of comprehensive and multilevel regional ecological security pattern and the protection and supervision of the ecological security pattern,measures are put forward in ecological construction and environmental protection of Jiangjin District,It provides a scientific basis and reference for the ecological protection and ecological security pattern construction in Jiangjin District. |
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