Study On The Space Demarcation And Control Measures Of Jinan City Based On The Niche Fitness Model

At present,we are experiencing an era of global ecological environment deterioration.Since the 20 th century,the acceleration of urbanization and population growth has led to the change of land use structure and the great development of social economy,but also brought the loss of biodiversity and the degradation of ecosystem services.At present,the strategy of ecological security pattern is one of the three strategic patterns of land space development and protection in China.It is very important to identify and improve the existing ecological security pattern,maintain the ecological integrity and high-quality environment to ensure the safety of species,habitats and various ecological processes,and the same is of great significance to realize the sustainable development of cities.In view of this,this paper takes Jinan,the capital city of Shandong Province,as an example,uses GIS technology and spatial analysis model to identify the important ecological sources of Jinan Based on the ecosystem service function,and evaluates the habitat quality based on invest model to build resistance surface.On this basis,using the circuit theory to identify the ecological corridor,ecological pinch point and obstacle area,and divide the ecological improvement area,which provides a scientific method for identifying the ecological elements of point,line and surface and constructing the ecological security pattern.These elements constitute the ecological security pattern of Jinan City.Based on the construction of ecological security pattern,the optimization development mode of "one center,two wings and two belts" is put forward,which provides spatial guidance for ecological protection in urban planning.(1)According to the ecological background characteristics of Jinan City,three ecosystem service functions of soil conservation,water conservation and carbon sequestration were selected for evaluation.The important ecosystem service function areas were identified as the ecological source areas,with a total area of 1349 square kilometers,accounting for 16.87% of the total area of Jinan City,mainly distributed in the southern mountainous areas.The important ecosystem service area of soil conservation is only 118 square kilometers,accounting for 1.47% of the total area,scattered in the southern mountain area;the important ecosystem service area of water conservation is 523 square kilometers,accounting for 6.54% of the total area,mainly distributed in the Yellow River,Xiaoqing River,Tuhai River and its connected water systems and surrounding patches.(2)Based on circuit theory,ecological corridor,ecological pinch point and obstacle area are identified.According to different resistance thresholds,the spatial distribution of ecological corridor was explored,and the reasonable range of ecological corridor was determined.48 corridors were identified,covering an area of1681 square kilometers,mainly forest land,cultivated land and grassland.The eastern corridor is spider like,and the southwest corridor is massive,especially the eastern corridor of Jinan City is more than 10 kilometers long,and the southwest corridor is more than 5 kilometers long.A total of 19 ecological pinch points were identified,mainly distributed in Zhangqiu district and Licheng District.The total area of obstacle identification is 1446 square kilometers,mainly distributed in Zhangqiu district and the north central part of Licheng District.Half of the ecological pinch points are located in the central area of the barrier area,and near the river or large area of construction land.Based on the above identification of ecological elements,a three-level ecological improvement area system is constructed.The areas of advanced improvement area,intermediate improvement area and low-level improvement area are 310 square kilometers,1136 square kilometers and 564 square kilometers respectively.(3)A model of "one center,two wings,two belts" ecological security pattern optimization is established,which centers on a large area of forest land in the southern mountain area,takes the southwest and Northeast Plain connected with the southern mountain area as the priority recovery area,and takes the Yellow River coast and the southern mountain area around as the ecological isolation zone.According to the results of this paper,the ecological source of Jinan City is strictly protected and diversity is promoted.This paper puts forward some suggestions on the construction of ecological corridor,priority protection and restoration of ecological pinch points and improvement areas.