Land Use Simulation Of The Poyang Lake Eco-economic Zone Taking Into Account The Ecological Network

As China has been vigorously promoting the new-type urbanization and implementing spatial planning policies,it is very important to coordinate the contradiction between human activities and ecosystem.Taking Poyang Lake Ecoeconomic Zone as a case,this paper constructs the ecological network in 2005,2010 and 2015,evaluates the structure of the ecological network,and puts forward the optimization schemes of the ecological network.On this basis,the land use patterns of Poyang Lake Eco-economic Zone under different scenarios in the future are predicted,and the ecological security situations under different scenarios are compared and analyzed to provide reference for the spatial planning.The main research contents and results are as follows:This paper selects the landscape pattern index of the study area from the two aspects of patch type and landscape scale,and makes a quantitative analysis on the landscape patterns and its change rule of the study area.The results show that: from2005 to 2015,the landscape patches of forest lands,cultivated lands and water areas tended to be fragmented,while the shape of urban lands and other construction lands tended to be regular;from 2005 to 2015,the overall landscape shape tended to be regular and stable,landscape connectivity declined,and patch types showed a balanced distribution trend.According to the method of Morphological Spatial Pattern Analysis(MSPA),this paper identifies the ecological source areas of the study area in 2005,2010 and 2015.According to the Minimum Cumulative Resistance model(MCR),this paper identifies the ecological corridors of the three periods.According to the intersection of the ecological corridors,the ecological nodes are identified.The importance of ecological sources,ecological corridors and ecological nodes is divided into three levels.The connectivity indexes are used to evaluate the overall structural stability and connectivity of the ecological network.The results show that: from 2005 to 2015,the numbers of ecological sources,ecological corridors and ecological nodes in Poyang Lake Ecoeconomic Zone decreased gradually.The extremely important ecological sources were mainly distributed in the north of the study area,the extremely important ecological corridors were mainly distributed in the south and east of the study area,and the extremely important ecological nodes were mainly distributed in the south and northeast of the study area.In 2015,the ecological network connectivity and stability were the highest.The main reason was that the number of ecological corridors was small but the distribution was concentrated.According to the proportion of ecological land areas of different levels of ecological sources,ecological corridors and ecological nodes in different distance buffer zones in 2015,the coordinated development scheme and the ecological protection scheme of ecological network optimization were determined: under the coordinated development scheme,the buffer zone widths of extremely important,important and general important ecological sources were 100 m,500m and 500 m respectively,the buffer zone widths of extremely important,important and general important ecological corridors were 600 m,600m and 200 m respectively,and the buffer zone widths of extremely important,important and general important ecological nodes were 1200 m,1200m and 800 m respectively;under the ecological protection scenario,the buffer zone widths of three levels of ecological source areas were all 500 m,and the buffer zone widths of three levels of ecological corridor were all 600 m,and the buffer zone widths of three ecological nodes were all 1200 m.After optimization,the shape of the ecological network will be more orderly and the connectivity of the landscape will be enhanced,which will be conducive to improving the stability of the ecosystem.By combining the multinomial logistic regression and multi-criteria evaluation method(MCE),the paper constructed the CA-Markov model to simulate the land use patterns of Poyang Lake Eco-economic Zone under the business-as-usual scenario,the coordinated development scenario and the ecological protection scenario in 2030.The results show that: from 2015-2030,the cultivated lands and forest lands areas of Poyang Lake Eco-economic Zone will decrease,the grasslands area will increase and the urban lands and lands for other construction purposes will increase significantly;the development of urban lands will be concentrated and continuous;The newly developed urban lands will be mainly distributed in Jiujiang,Nanchang,Jingdezhen and Shangrao under three scenarios;The newly developed lands for other construction purposes will be mainly distributed in Jiujiang,Nanchang,Shangrao and Jingdezhen under the business-as-usual scenario,and in Jiujiang,Nanchang,Shangrao and Yichun under the coordinated development scenario and the ecological protection scenario.This paper evaluates the land ecological security patterns of 6km × 6km grids in the study area under three scenarios in 2030.The results show that: in 2030,the average ecological security values of the grids in the Poyang Lake Eco-economic Zone under the business-as-usual scenario,the coordinated development scenario,and the ecological protection scenario will be 0.5829,0.5843,and 0.5845,respectively;Under the coordinated development scenario and ecological protection scenario,the areas of high ecological security will be significantly larger than those under business-as-usual scenarios,while there will be no significant difference between the coordinated development scenario and the ecological protection scenario;The overall characteristics of the land ecological security patterns under three scenarios will be high in the middle and surrounding regions,but low in other regions;Under the coordinated development scenario and the ecological protection scenario,the area of regions with high ecological security under the northwest and northeast will be significantly larger than that under the business-as-usual scenario,which indicates that restricting the ecological network regions from transforming into construction lands will help improve the ecological security.