| With the proposal of the “The belt and road”,the Ili river is a cross border between China and Kazakhstan,how to jointly develop the Ili River Basin and protect the ecological environment of the Ili River Basin has become a common concern of the two countries.In this paper,meteorological data,remote sensing data,land use cover data,soil data and various biological parameter data tables are used to estimate the water source conservation and the NPP of the Ili River Basin ecosystem.We analyze the temporal and spatial characteristics of two services of the Ili River Basin,and the impact of land use types and terrain factors on the ecosystem services in the Ili River Basin,intensive study of the relationship between different ecosystem services,identified effectively the hot spots of two ecosystems in Ili River Basin.From the perspective of ecosystem services,this paper puts forward suggestions on the protection of cross-border river basin ecosystem to improve the overall benefits of the basin ecosystem.The main conclusions are as follows:(1)The photosynthetic effective radiation of Ili River Basin is the largest in summer,especially in June.Its distribution is mainly related to NDVI of vegetation.The actual light utilization rate of vegetation in autumn and winter is higher than that in spring and summer.The net primary productivity of vegetation in Ili River Basin showed a fluctuating growth trend.The net primary productivity of vegetation in the upper reaches of Ili River in China: Summer > Spring > Autumn > Winter.The net primary productivity of vegetation in the middle and lower reaches of Ili River in Kazakhstan: Spring > Summer > Autumn > Winter.The NPP is distributed circularly along the Tianshan Mountains,with low in the middle,high around,high in the southeast and low in the northwest.From 1997 to 2017,the NPP of different land types showed an increasing trend of fluctuation,including Woodland > Sparse woodland >Medium coverage grassland > High coverage grassland > Town > Cultivated land >Low coverage grassland > Wetland > Shrubbery > Bare land > Water area > Other unused land.According to the effect of different slopes on NPP,the NPP of slope and gentle slope is larger than that of flat slope and dangerous slope.The slope direction has little effect on NPP with altitude of 500-1500 m and > 3500 m,in 1500-3500 m altitude,the NPP in different slope directions is as follows: Shady slope > Northwest slope >Northeast Slope > Southeast slope > Southwest slope > Sunny slope > No slope direction,this is mainly affected by the type of land use.(2)From 1997 to 2017,the spatial distribution of water production in Ili River Basin was low in the northwest and high in the southeast.The high value area was located in the forest and grassland distribution area of Tianshan Mountains,while the low value area was located in the human activity area of plain valley.From 1997 to2017,the spatial distribution of water conservation and water yield in the ecosystem of Ili River Basin is basically the same,which shows that the distribution of water conservation is mainly related to water yield,and the water conservation of Ili River Basin is generally in a positive trend.The spatial distribution of water conservation and water yield in Ili River Basin is basically the same.The contribution of water conservation of different land use types is higher for forest land and grassland,while the contribution rate is lowest for cultivated land,water area and unused land.The contribution of water conservation in different slope directions is better when it is close to the unit area of shady slope,and worse when it is close to the unit area of sunny slope.The contribution rate of water conservation is higher in flat slope,gentle slope and slope,but lower in sharp slope and steep slope.At the altitude of 500-1500 m and above 3500 m,the water conservation is low.At the altitude of 1500-3500 m,the water conservation is high.(3)From 1997 to 2007,the water conservation and vegetation NPP of Ili River basin ecosystem were synergetic.The high value areas of two ecosystem services in Ili River Basin are located near the foot of Tianshan Mountain,and the low value areas are located in Ili River Valley,kapchagai reservoir in the middle reaches and the lower reaches of Ili River Delta.By Quantile method,Ili River basin can be divided into five ecological service areas.Combined with the two ecosystem services,three suggestions are put forward for the protection of the ecosystem of Ili River cross-border River Basin. |
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