Study On Supply And Demand Relationship Of Key Ecosystem Services In Shiyang River Basin

Under the background of rapid urbanization and industrialization,the continuous expansion of urban space and the continuous transformation of land use structure have led to serious compression of ecological space,continuous reduction of the supply capacity of ecosystem services,and continuous increase in the demand for human social and economic development.From the perspective of ecosystem service supply and demand,seeking to solve the sustainable development of regional ecological and economic win-win has become the focus of scholars'attention and it has also become an important indicator to measure the level of regional social and economic development.The Shiyang River Basin is a leading area for the country to build an ecological security barrier.In recent years,with the rapid social and economic development,the river basin has become the area with the highest population density and the most serious imbalance between water supply and demand in the inland river basin of Hexi,and its special geographical location as a result,the lower reaches of the basin are surrounded by the Tengger and Badain Jaran deserts.Desertification and desertification pose a serious threat to the lives and property safety of the people in the basin and social and economic development.Therefore,this study starts with the two key ecological elements of water and sand that restrict the sustainable development of the watershed.With the support of multiple sources of data such as land use data,remote sensing data,soil data and statistical data,the In VEST model,RWEQ model,etc.are used.A quantitative method to evaluate the supply and demand of water service and windbreak and sand fixation service in the Shiyang River Basin in 2000,2010,and 2018,is used along with the ecosystem service supply-demand ratio index model,the ecosystem service supply-demand coupling coordination model,and bivariate spatial partial autocorrelation model,correlation analysis and other methods to clarify the supply and demand quantitative relationship,spatial matching relationship,spatial coupling and coordination relationship,spatial agglomeration degree,and the supply-demand ratio of the two key ecosystem services in different periods of water service and windbreak and sand fixation service.The trade-off and coordination relationship between the two is expected to provide scientific basis and theoretical support for the sustainable development of the Shiyang River Basin's ecology and economy.The main conclusions are as follows:(1)From 2000 to 2018,the supply of water service per unit area was 42.82m~3/ha?33.80m~3/ha?55.77m~3/ha.The change trend first decreased and then increased.The change pattern showed a decreasing pattern from upstream to downstream.The demand per unit area was 58.77m~3/ha?52.76m~3/ha?50.09m~3/ha,respectively.The trend of change was gradually decreasing,and the pattern of change shows a decreasing distribution from upstream to downstream,and the balance of supply and demand was shifting to a more balanced state.The spatial matching relationship between supply and demand of water service was dominated by low supply-low demand matching and high supply-low demand matching.The areas with significant changes were mainly distributed in Tianzhu area,Liangzhou District and Minqin County;the degree of spatial agglomeration was from lower to lower;spatial coordination was led by low-degree coordination.(2)From 2000 to 2018,the supply of windbreak and sand fixation service per unit area was 18.33kg/m~2?21.94kg/m~2?22.51kg/m~2,respectively.The trend of change was gradually increasing,and the pattern of change showed a decreasing distribution from midstream to upstream and downstream.The demand per unit area was21.54kg/m~2?19.40kg/m~2?21.64kg/m~2,the change trend first decreases and then increases,and the change pattern presents an increasing distribution characteristic from upstream to downstream.The change trend of the supply and demand index of windbreak and sand fixation service first increased and then decreased.The balance of supply and demand changed from short supply to oversupply.The spatial matching relationship between the supply and demand of windbreak and sand fixation service was dominated by high supply-low demand and low supply-low demand matching.The significant changes were mainly located in the north-central Gulang County,the northern Tianzhu Region,the northern Liangzhou district,Minqin Oasis and Sandy area at the periphery of the oasis;the degree of spatial agglomeration was dominated by low-high agglomeration and high-low agglomeration;spatial coordination was dominated by high-level coordination and low-level coordination.(3)From 2000 to 2018,the average index of comprehensive ecosystem service supply was 0.3453,0.3569,and 0.3701,respectively.The trend of change was gradually increasing,and the pattern of change showed a decreasing distribution characteristic from the midstream to the upper and lower reaches;the average demand index was 0.1943,0.1466,0.2289,respectively.The trend of change first decreased and then increased,and the change pattern showed an increasing distribution characteristic from upstream to downstream.The change trend of the comprehensive ecosystem service supply and demand index increased first and then decreased.The spatial distribution showed a spatial heterogeneity distribution pattern from upstream surplus to downstream deficit.The spatial matching relationship between the supply and demand of comprehensive ecosystem service was dominated by high-supply-low-demand and low-supply-high-demand matching.The areas with significant changes were mainly distributed in Liangzhou District;the degree of spatial agglomeration was dominated by low-high agglomeration and high-low agglomeration;spatial coordination was dominated by low coordination and moderate coordination.(4)From 2000 to 2018,the supply of water service and windbreak and sand fixation service in the Shiyang River Basin had shown significant synergies.There was a significant trade-off relationship,and the balance of supply and demand presents a significant synergy relationship.When the supply correlation coefficience was greater than 0,the change trend of the synergy relationship weakens first and then gradually stabilizes;the demand correlation coefficience was less than 0,and the change trend of the trade-off relationship continues to increase;the supply and demand balance correlation coefficience was greater than 0,and the change trend of the synergy relationship first strengthens and then weakens.In terms of spatial expression,the supply balance coordination relationship was dominated by the low-low agglomeration type;the demand balance coordination relationship was dominated by the low-high agglomeration type;the supply-demand balance coordination relationship was dominated by the low-low agglomeration type.