Land Use Multifunction Assessment From The Perspective Of Social-ecological Complex Systems InThe Loess Hilly Area Of Central Gansu

Recently,with the rapid development of social economy and urbanization,more and more attention had been paid to the harmonious development of man and nature.With the coordinated development of ecological environment and social economy,social-ecological complex systems research and land use multi-functionality have become the hotspots and frontier issues.The study of land use gradually attracted widespread attention at home and abroad,from a single functional evaluation to multi-functional evaluation,and to the temporal-spatial evaluation.Nowadays,the multifunctional assessment of land use is still at the initial stage,and has not formed a unified evaluation standard system,while the evaluation methods are still in the exploration process,in addition,the evaluation scale based on the county and township is very rare.Temporal and spatial variation study of land use multifunction has great significance for the sustainable development of Anding District.Anding District of Dingxi city is located in the loess hill gully area of Central Gansu,with the terrain ups and downs,deep gully in the mountains,is one of the serious soil erosion area.From the perspective of social-ecological complex systems concept,this paper will be extended to the three functions of land use ecological,economic and social from the single function evaluation and further analysis the specific eight sub-functions of land use based on the three functions.With the using of the grey relation projection and AHP methods to evaluate land use multifunction of Anding District and small towns,and to discuss the correlation of land use change and land use multifunction.The results were listed as below:(1)The main land use types were the cultivated land and grassland in Anding District with the proportion of 45.66% and 29.18% respectively,the land use conversion of cultivated land and grassland were the bigger during 1990-2015,the cultivated land showed an increasing trend,whilethe grassland decreased rapidly,and the forest land showed an increasing trend in recent years.The increase of the forest land played an important role on the improvement the ecological environment and economic development and social stability of the study area.The degree of landscape fragmentation,landscape heterogeneity and landscape diversity showed a trend of increase after the first drop in the study area.(2)The land use total function showed a growth trend after a decrease,the ecological function and the economic function first slowly decreased,then increased.The values of the total land use function,the ecological function and the economic function in 2015 were 0.73,0.69 and0.75,respectively.The total function and economic function characterised a high degree level of sustainable development.The social function showed a continuous fluctuation change from 1990 to 2015.The social function was the highest one in 2000,as 0.65,while it was 0.51 in 2015.The development focus transformation from ecology to economic in Anding District.From the perspective of the comprehensive development of all villages and towns,the general function was relatively higher in Gaofeng Country,Xiangquan Town,Fujiachuan Town,Neiguanying Town,Chankou Town,Fengxiang Town,while of which is the lower in Ningyuan Town and Xinji Country.(3)The eight sub-functions based on the function value in Anding District in 2015 was as below: the ecological regulating function >the employment support function >the social security function>the agricultural production function>the living home function>the resource supply function>the ecological maintain function>the economical development function.The function levels of the ecological regulating function,the employment support function,the social security function,the agricultural production function were the high level for regional sustainable development.(4)The temporal and spatial variation of the coupling of land use multifunction of social ecological complex systems was very small in Anding District from 1990 to 2015 with the spatial difference being small,and the ecological,economic and social functions interacted with each other was not strong,and belong to the antagonistic stage.The temporal and spatial variation of the coupling coordination of land use multifunction was small too,the coupling coordination was slightly higher than the coupling and belong to the moderate coupling coordination stage.The coupling between the ecological-economical,ecological-social,economical-social functions was low and belong to the antagonistic stage,between which the coupling coordination was high above0.5,belong to a highly coupled coordination stage,and the study area showed preliminary synergistic effect with an increasing trend.(5)There was certain correlation between different land use types and land use multifunction.The correlation between forest land and land use multifunction was relatively highest.The correlation of the forest and the ecological function or the total function reached more than 0.5,and the correlation with which the economic function,the ecological regulating function,the economic development function and the social security function was over 0.3.The cultivated land and ecological maintaining function had strong negative correlation,and the cultivated land and the ecological function had negative correlation,while there was the positive correlation bewteen the cultivated land and the agricultural production function,the employment support function;The grassland was negatively correlated with many functions what showed a decreased trend;Construction related positively with the economical function;The correlations of waters,unused land and the land use multifunction were weak,which affected indirectly many functions of land use with the complex internal impact mechanism.