| Land use / Cover Change(LUCC)research is a hot topic of global change research in recent years,and land use change simulation is an important aspect of LUCC research.To explore and understand the process and law of regional land use change is conducive to grasp the future development direction of land use and promote the rational allocation of land resources.Due to the limited land resources on the earth,it will become very scarce with the further development of human beings.Through the study of land use simulation and optimization,the spatial distribution of urban land use in the future can be obtained in advance,which has certain reference value for the future urban land use;optimizing the land use structure can improve the utilization efficiency of land resources,fully tap the potential value,which is conducive to the sustainable development of resource-saving society.Taking Wanzhou District of Chongqing as an example,based on the current data of land use in 2009,2013 and 2017,the land use types are generally divided into seven land use types: cultivated land,garden land,forest land,grassland,construction land,water area and other land.This paper analyzes the change of land use in the study area from the four aspects of land use change amplitude,change degree,change speed and land use transfer,and selects nine driving factors that affect the change of land use in combination with the actual situation of the study area.Using the “coupled” Markov flus model to set the relevant parameters,this paper forecasts the quantitative structure of land use in the future four scenarios in 2035,tests the credibility of the simulation model,simulates and analyzes the land use situation of the study area in different scenarios.Finally,based on the grey linear programming theory,the function equation is constructed with the economic benefit as the goal,and the constraints are constructed with the social benefit and the ecological environment benefit as the goal to optimize the land use structure of the study area,and the corresponding countermeasures and suggestions are put forward according to the optimization results.The main results are as follows:(1)During 2009-2017,the cultivated land and construction land changed greatly,with a decrease of 1221.08 hectares and an increase of 1849.17 hectares.Garden land,forest land,grassland and water area also showed a small reduction trend,reducing 273.32 hectares,26.49 hectares,112.02 hectares and 247.62 hectares respectively,and other land increased 31.54 hectares.The comprehensive dynamic degree of land use in 2009-2013 is 0.17 higher than that in 2013-2017,indicating that the land activity in the previous land use period is higher than that in the later period.(2)By analyzing the transformation matrix of land use2009-2017,it can be found that the largest amount of land use transfer out in Wanzhou District is 2226.42 hectares of cultivated land,of which 25.93% is converted into forest land and 71.44% into construction land.Among the seven types of land use,the largest change is construction land,followed by arable land and woodland.The area of garden land,forest land,grassland and water area converted into construction land is 225.00 hectares,594.54 hectares,109.49 hectares and 255.60 hectares respectively,which is due to the large expansion of other types of land occupied with population growth and social and economic development,transportation and infrastructure construction needs.In terms of the selection of factors affecting land use change,eight driving factors of nature,location and social economy are selected in combination with the actual situation of Wanzhou District.The ROC test value is greater than 0.7 through regression analysis,which shows that the selected driving factors are reliable and can be used for the simulation of land use change.(3)the coupled Markov plus model can well solve the process of quantitative change prediction and spatial simulation in land use change simulation.After setting conversion rules,neighborhood factors and other parameters to verify the land use situation in 2017 based on the land use status in 2009,the results show that the number of correct grids in the simulation reaches 326344,with an overall accuracy of 94.20% The simulation accuracy of land type is also over 90%;Kappa index is 0.9248,which is far more than 0.75,overalcaccuracy = 0.9470,which indicates that the overall simulation accuracy is high.This model can be used to simulate the future land use situation of multi scenario in Wanzhou District.(4)under the natural growth scenario,cultivated land protection scenario,ecological protection scenario and comprehensive development scenario,the land use changes in Wanzhou District in 2035 are different.Under the situation of natural growth,the increased construction land is mainly around the construction land along both sides of the Yangtze River,as well as the scattered growth of urban industrial and mining land and transportation land.The reduced cultivated land area is mainly in the northwest.The garden land is mainly distributed in the towns near Dazhou town and Xiaozhou town in the north,and the reduced forest areas are mainly concentrated in Xintian Town,Changling Town Chenjiaba street,Zhonggulou street,Tiancheng Town,xiongjia town and other areas;the distribution and reduction of grassland are relatively scattered in all parts of the study area;the reduction grid of water area is mainly divided into Shahe street,Zhoujiaba street and Taibai street;the distribution of other land is basically the same due to the small number during the study period.In the case of cultivated land protection,the limitation of basic farmland protection area is added,which reduces 1713 hectares of cultivated land compared with that in the case of natural development,ensuring the quantity and quality of cultivated land.The number of forest land and grass decreased,mainly converted to construction land,and the number of forest land,water area and other land basically remained unchanged.In the context of ecological protection,the ecological protection restriction zone is set up to ensure that the garden,forest land and water area in the ecological protection zone do not transform into other land types,reduce the transfer amount,ensure the area of ecological land,and further protect the ecological land.In the context of comprehensive development,the number of grids of land use in this scenario is compared with that in the natural development scenario.It can be seen that all kinds of land use have been changed in a balanced way.Therefore,compared with a single land use model scenario,the comprehensive development scenario is more reasonable in the spatial layout of land use.According to the simulation results,the space of “one center,three axes,five horizontals and many points” in Wanzhou District is constructed.(5)land use structure optimization.Based on the theory of grey linear programming,according to the needs of social and economic development in Wanzhou District,the objective function is established with the maximization of economic benefits as the goal,and the constraints are set with the social and ecological benefits as the constraints.The optimization model of land use structure in Wanzhou District is constructed.The optimization scheme of land use structure in 2035 is solved by lingo software,and some suggestions for land use are put forward ?... |
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