| Land is the basis of life and production.Therefore,any human activity cannot be separated from the support of land resources.At the same time,the limitation of land resources requires that human beings should adhere to the concept of sustainable development in the process of land resources development and utilization.Because of the changes of land usage,it leads to the loss of ecosystem services value in the whole region.Most importantly,it may have a negative impact on the regional ecological environment.With the development of social economy,the conflict between man and land becomes more and more serious.Therefore,from the perspective of sustainable development and with the support of RS and GIS technology,this paper took Zhaohua District,Guangyuan as the research object.Five remote sensing image maps of 2000,2005,2010,2015 and 2017 were selected to analyze Zhaohua District comprehensively,and based on the method of usage transfer matrix,land use dynamic degree,land use degree and structure.So I analyzed the land usage changes in past 17 years of Zhaohua District.On the basis,the driving factors of land usage changes were analyzed and the ecosystem service value coefficient was formulated by referring to Costanza and Xie Gaodi,etc.Then I adjusted to conform to the ecological value service coefficient of Zhaohua District based on the actual situation.In addition,the ecosystem service function of Zhaohua District in 17 years was evaluated.From this,a grey linear programming model was established to calculate and analyze the most reasonable land usage structure allocation in Zhaohua District in 2025,and a reasonable land use structure optimization plan is proposed.(1)Based on the analysis of the overall change of land usage area data in Zhaohua District from 2000 to 2017,and from the point of view of the overall change of land usage,we inferred that the construction land and water area in Zhaohua District was increasing continuously.The cultivated land and unused land was decreasing continuously.The woodland and grassland was decreasing first and then increasing.By using the transfer matrix method,it was concluded that the area of transfer from land usage types to land usage changed obviously;and the amount of transfer between construction land,forest land and cultivated land was the largest;and construction land was mainly transferred from cultivated land and woodland;cultivated land was mainly transferred from woodland and construction land;woodland was mainly transferred from cultivated land and grassland.Meanwhile,by calculating the formula of dynamic degree of land use,it was calculated that the speed of land use in Zhaohua District had changed obviously during the study period,and the land usage types changed in different degrees.Among them,construction land increased the fastest which increased by 2.71 times.Then followed by water area,increased by 1.76 times,and unused land decreased by 41.56%.Through the calculation formula of land usage degree and structure,the soil in Zhaohua District was calculated.The degree and structure of land usage change were increased and tended to be stable.(2)By using Costanza's method of calculating ecosystem service value,and referring to Xie Gaodi's research method,combining domestic research on the value coefficient of ecosystem services for calculating construction land,the ecosystem services value coefficients which were in line with the actual situation of Zhaohua District were worked out,and the 17 years ecosystem service value of Zhaohua District was calculated.From which we can got that the total ecosystem services value of Zhaohua District showed a fluctuating state of decreasing first and then increasing in 2000-2017,with an overall net increase of 1.39%.From the contribution rate of each land usage type to the ecological benefit of Zhaohua District,forest land,cultivated land and water area were the three main land types that contributed most to the ecosystem service value of Zhaohua District,while grassland and unused land contributed less.Water conservation,soil formation and protection,gas regulation,biodiversity conservation,climate regulation and raw materials were the major contributors to the ecosystem service value of the study area.The sensitivity index of ecosystem service value in Zhaohua District was less than 1,so the results were credible.(3)In this paper,the grey linear programming method was used to construct the optimal allocation model of land use in Zhaohua District.Taking maximizing the value of ecosystem services as the optimization objective,seven constraints were set according to the current situation of land use in Zhaohua District,and the objective function was established under the condition of meeting the constraints.By using Lingo linear programming and other calculation software,the optimal allocation scheme of land usage structure in Zhaohua District in 2025 based on maximizing the value of ecosystem services was obtained,and compared with the current land resources in Zhaohua District.After optimization,the value of ecosystem services was 757,901,500 yuan,which was an increase of 14.906 million yuan from the value of ecosystem services in 2017.On this basis,the proposed measures for optimizing the land use structure in Zhaohua District can be used to make more efficient use of land resources and promote ecological construction. |
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