Evaluation Of Water Supply And Water And Soil Conservation Ecosystem Services In Dalian

In recent years,with the continuous improvement of the level of social productivity,the ability of human beings to transform nature has been enhanced,resulting in the dramatic changes of natural ecosystems,the continuous emergence and deterioration of ecological problems,and the increasingly serious adverse effects on human well-being.The protection of ecological systems has gradually become the focus of the world today.In order to solve the need of land for urbanization construction in Dalian city,the phenomenon of "splitting mountains to fill the sea" and "splitting mountains to build cities" occurs from time to time,which causes serious damage to the natural landscape,forest vegetation and ecological environment and reduces the ecosystem service function.Therefore,it is necessary to evaluate the ecosystem service function of Dalian.In Dalian city as the study area,this study based on GIS and remote sensing technology,based on the data of land use,combined with the soil data,meteorological data and other related data,using In VEST model of water supply,soil conservation module,respectively for 1980-2015 in Dalian water supply,soil conservation function quantitative assessment,and set up four kinds of situation,to discuss climate change and land use from 1980 to 2015 in Dalian city water supply and soil conservation ecosystem service function and the effect of for the protection and development of natural resources in Dalian providing visual assessment results and the basis,We will raise awareness of the ecological red line protection for the whole society.This paper draws the following main conclusions:(1)Land use types in Dalian city are mainly cultivated land and forest land.The area of cultivated land and forest land decreased during the study period.Urban construction land area has increased,mainly by the transfer of farmland.The area of other land types varies little.(2)During 1980-2015,the average annual precipitation and potential evapotranspiration in Dalian did not decrease significantly,the average annual temperature and drying coefficient increased significantly,and the average annual actual evapotranspiration decreased significantly.(3)From 1980 to 2015,the average annual water supply in Dalian was 226.36 mm,accounting for 33.41% of the precipitation.During the study period,the average water supply did not decrease significantly,with a rate of 14.7mm/10 a.Spatially,water supply fluctuatesfrom northeast to southwest.The high-value areas are mainly concentrated in the northeast of Zhuanghe city,the south of Wafangdian city and the middle of seven districts and counties in the south.The water supply in the southwest of the seven districts and counties in the south and the northeast of Wafangdian city is relatively small,concentrated in 1.11-168.62 mm.From the perspective of the total water supply,Zhuanghe city has the largest annual total water supply,reaching 1.1 billion m3.Precipitation is the main climatic factor that affects the water supply of Dalian city.The water supply per unit area of construction land is the largest,up to 355.23mm/m~2.The water supply per unit area decreases with the increase of the altitude,and the water supply capacity of the area <133m is higher,and the total water supply is21×105mm.(4)From 1980 to 2015,the soil erosion modulus in Dalian city was 265.26 t/km.a,and the rising rate was 11.24 t/km.a / 10 a.On the whole,soil retention showed an insignificant upward trend,with a rate of 191.72t/10 a,and the overall soil retention capacity of the study area was good.From the perspective of spatial variation,the total area of micro-erosion and mild erosion is 10993.96km~2,accounting for 93.7% of the total area of the study area.The soil erosion area of Zhuanghe city is the largest,which is 3866.6 km~2,accounting for 29.3% of the total area of the study area.The soil erosion area of Pulandian city is the smallest,which is2760km~2,accounting for 20.9% of the total area of the study area.Among different land use types,the soil retention amount of forest land is the largest,which is 8136t/km~2,accounting for 47.6% of the soil retention amount.The minimum soil retention of unused land(bare land)is 236t/km~2,accounting for 1.4% of the soil retention.From 1980 to 2015,the amount of soil per unit area in Dalian increased with the elevation.In the area with a high elevation of 438-1110 m,the soil retention was large,25801.27t/km~2,accounting for 44.09% of the total soil retention.The low elevation areas have low soil retention.(5)Based on GDP and population density,the demand intensity of ecosystem services in Dalian city is distributed in a pattern from high in the south to low in the north,and the demand intensity of ecosystem keeps increasing.The most important ecosystem service supply area was 5271km~2,accounting for 45.48% of the total area of the study area.Zhuanghe city was a highly important ecosystem service supply area.The general demand area of ecosystem services is the largest,which is 8118km~2,accounting for 69.28% of the total area of the study area.The seven districts and counties in the south are the areas with high demand for ecosystem services.