Land Use Optimal Allocation Based On CLUE-S And MCR Model In Shiyang River Basin

With the deeply study of the land use spatial distribution,patterns and change process,the landscape using and optimization are paid more attention to the ecological environmental construction.The land use layouts not only optimize from amount and spatial distribution,but also allocated from ecological process according to land use units.Shiyang river basin locates in the east of Hexi Corridor,Gansu province.It is one of three inland rivers in Hexi Corridor.Due to unique physiographic conditions and profound effects of human activities,the river basin has been facing serious ecosystems degradation and ecological crisis such as ground water supply reducing,water table descend,soil salinization,desertification,forest degradation and so on.It is being the typical ecological degradation area in inland and the concerned focus of the whole society.In this paper,landscape elements were classified as fourteen types by the means of supervised classification and visual interpretation with Landsat TM/ETM/OLI images in 1986,2000,2007and 2015.In addition ancillary data with the help of GIS techno1ogy,mathematics model and landscape ecology theory.Based on the land use patches generalization,rectification and topology check,the land use distribution pattern,spatio-temporal evolution characteristics and main driving factors.And then CLUE-S(conversion of land use and its effects at small regional extent)integrated MODP(Multi-objective Dynamic Programming)model as well as Binary Logistic regression methods were applied to predict and simulate three optimization scenarios of land use allocation,which were named ecological security scenario(ESS),farmland protection scenario(FPS),and free development scenario(FDS)respectively in 2020,2025 and 2030.At last,the GIS technologies of spatial analysis and the MCR(Minimum cumulative resistance)model were used to calculated the ecological security optimization results,and combined the ESPS which was simulated by CLUE-S model.The last optimized allocation of land use was obtained which contain ecological security pattern(ESP),farmland protection scenario(FPS),and free development scenario(FDS).The application of the combined MCR,CLUE-S model and GIS in Shiyang River Basin suggests that this methodology has the capacity to optimize the land use allocation through considering the ecological process and ecological resistance of landscape elements among land use types.This study included the following sections.(1)The main land use types were unused land,grassland,and farmland in Shiyang River Basin and the spatial distribution of various land use types had more obvious vertical zonality.Compared to the four research period from 1986 to2015,the unused land accounted for about 47%of the total area of the whole basin,grassland accounted for about 27%,and other land use types were farmland,woodland,urban and residential land and water area.Seen from the area change of land use,the farmland was increased from 6507.42 km~2(about 16.03%of the total area)in 1986 to 7032.62 km~2 in 2007(about 17.33%),and increased area mainly concentrated in the middle and lower reaches,the peripheral part of wuwei and minqin oasis.The area of farmland increased 7.83%from 1986 to 2015.Howere,the woodland and grassland reduced from 2676.49 km~2(6.59%)and 11280.10 km~2(27.80%)in 1986 to 2482.84 km~2(6.11%)and 11023.89 km~2(27.17%)in 2015respectively,reduced with a total area of 6.46 km~2 and 8.54 km~2 per year in the past 30year.Moreover,urban and residential land increased more obviously,accounted the area of 176.7 km~2,which was about 48.57%of the total area of urban and residential land.Water area increased since 2007,which mainly contained the reservoir and the urban artificial landscape water surface.Unused land reduced a lot,which mainly concentrated in north of Liangzhou district and north and east of Minqin county.From the Qilian Mountain of the southern to the desert areas of the northern part,the distribution of the main landscape types shows as follows:Glacier and perpetual snow?Cold desert?Marsh?Grassland?Woodland?Farmland?Residential area?Bare soil?Sandy deser.Along with elevation reduction,various types of landscape overlay one another,cross-distribution.The distributed lines are blurry gradually from south to north,especially at an altitude of 2000 meters below.(2)Through the CLUE-S model intergrated MODP model and the driving factors of land use change,the Binary Logistic regression method was used to obtain three different scenarios of land use spatial optimization distribution.Results showed that the ESS scenario is designed for protecting the ecological zones of water body and woodland,and preventing from destroying environment of water resource area and the woodland protective area,in order to effectively protect the scope of the ecological security.The FPS scenario is aimed at effectively protecting farmland resource and strictly carrying out farmland protection policy.In addition,the old and discarded homestead is also converted into farmland in order to keep stability of the farmland area.The FDS scenario only considers the natural development of the land use type and spatial structure at present.Under ESS,farmland was reduced,but woodland,grassland and water body were increased significantly,and under FPS,land for construction was controlled effectively,a large parts of homestead were converted into farmland,and potential of unused land was developed vigorously.Furthermore,the current free development situation and the government macro policy guidance were comprehensively considered and the quantity and spatial structure development were also taken into consideration under FDS.(3)The ecological sources and life expansion sources were taken as input and imported into the Cost Distance module in ArcGIS software,and calculated the MCR value.Shiyang River Basin was divided into prohibited development area,restricted development area,key development area,optimized development area and ecological comprehensive management area.The results indicated that the prohibited development area mainly distributed high altitude region in the south Qilian Mountain and low altitude region where had high density of rivers.These areas were covered by a large quantity of glacier,permanent snow,river and other natural landscape,which have important influence to the local eco-environment,hence should be strictly protect in future.This area had the maximum area of 6269.47km~2,which accounted for 15.45%of the total area of Shiyang River Basin.Restricted development area mainly distributed in the north of Tianzhu county,middle and south of Liangzhou district,north of Gulang county and the oasis basin of Jinchuan district and Minqin county.The area was about 9473.63 km~2,which accounted for 23.35%of the total area.Key development area was mainly distributed in the middle reaches,where included Liangzhou district center and the surrounding area,most of Jinchuan district and north of Yongchang,Minqin county,had a total area of 9864.03 km~2,which accounted for 24.31%of the total area of the whole basin.Optimized development was distributed the transition zone between key development area and ecological comprehensive management area,these area was also the key area of land reclamation,land development,industrial development and urban and residential land expansion in the future.Ecological comprehensive management area was mainly distributed in north of Gulang county,northeast of Liangzhou district and north of Minqin county,where was the focus of ecological restoration,ecological industry development area in the future.These area should be reinforced the management by different governments,actively explore the natural ecological restoration,and try to ecological industry as well as ecological industrial chain.Area of ecological comprehensive management was 6269.47 km~2,accounting for 15.45%of the total area of the basin.(4)Based on MCR model,CLUE-S model,the ecological security pattern of the cost resistance model and the land use spatial distribution,this paper proposed a method of land use optimal allocation based on ecological security pattern.The method can intergrated the qualitative analysis,quantitative calculation,model simulation,and land use change process,and the ecological process,and comprehensive judge landscape elements,spatial location and connection,which palyed key role to the land use change and ecological security.This model can also combine with an planning approach,to simulate and optimize the land use scenario based on the ESP in a regional landscape.The combination of CLUE-S and MCR can give full play to the advantages of model coupling,which both improves the reasonableness and accuracy of the model for land use scenario simulation and effectively improve the optimization methods under ecological process.The approach presented in this study will be helpful to understand the ecological process of land use change and provide scientific support for land use planning and managements.