Spatiotemporal Patterns Of Ecosystem Services And Influencing Factors In The Mu Us Sandy Land,China

The Mu Us Sandy Land is located in the farming-pastoral ecotone of the northern China.It is a very special and sensitive ecotone,and also an important ecological barrier in northern China.The special natural ecological background determines the fragility and vulnerability of its ecological environment.Coupled with long-term unreasonable human activities,the ecological environment in the region has been deteriorating.In recent years,the desertification degree of the region has been reversed.However,how regional ecosystem services changed required further study.Therefore,based on the combination of remote sensing images,meteorological data,socio-economic data,and literature data,this study used the method of material quality assessment to evaluate the supplying services,regulating services,and cultural services of the Mu Us Sandy Land from 2000 to 2013 based on the ecosystem service mechanism.The combination of qualitative and quantitative analysis reveals the influencing factors of regional ecosystem service change from the aspects of policy,land use/cover change,vegetation coverage,and climate change.The main results were as follows:(1)Ecosystem services in the Mu Us Sandy Land have shown an increasing trend.In terms of supporting services,the grain yield and meat production in the Mu Us Sandy Land showed a logarithmic and linear growth trend from 2000 to 2013,respectively.The average annual growth of grain production and meat production is 6.72×104 tons and 1.02×104 tons respectively.The high-yield food areas are concentrated in the southeast of the sand,and the meat-producing areas are concentrated in the northwest in the spatial pattern.In terms of regulating services,the average annual wind erosion was dominated by slight and mild erosion,and the average soil wind erosion modulus was 1827.72 t/(km2·a).The wind erosion showed a fluctuating downward trend from 2000 to 2013 in the Mu Us Sandy Land.The average annual reduction is 0.02×108t.The more severely eroded areas were mainly distributed in the hinterland of Uxin Banner.In terms of carbon storage,the average annual carbon storage in sandy land was 179.29 TgC.From 2000 to 2013,the carbon storage showed a fluctuating upward trend with an average annual growth of 10.39 TgC.The regions with higher annual average carbon storage were mainly concentrated in the typical grassland and desert steppe areas in the western and northeastern sand regions.In terms of dust weather regulation,the average number of days of dusty weather is 13 days.The number of dust days increased first and then decreased significantly from 2000 to 2013.Average annual decrease of 2 days.The annual average number of sandstorm days in the southwestern was higher than that in the northeast.In terms of PM2.5 concentration adjustment,the air quality in the Mu Us Sandy Land is good.The average PM2.5 concentration is 16.21 ?g/m3 from 2000 to 2013.The PM2.5 concentration in the sandy land showed a fluctuating characteristic,which showed a spatial shift from the south to the southeast.In terms of cultural services,the growth of scientific research output and personnel training in the Mu Us Sandy Land is divided into two phases.Prior to 2008,the number of scientific research outputs and personnel training in the internal counties of the sandy land showed steady growth.After 2008,it is in a state of rapid growth.The amount of scientific research and personnel training in the northern is higher than southern at Mu Us Sandy Land.(2)There is a good correlation between ecosystem services and policies,land use structure change,vegetation coverage and meteorological factors in the Mu Us Sandy Land.From 2000 to 2013,the implementation of a number of forestry ecological projects such as the three-north shelterbelt in Mu Us Sandy Land had significant effects on the treatment of desertification land.Measures such as afforestation and enclosure have greatly increased the area of forest and grassland in the region.Accumulative afforestation area of 1.38×104 km2 over the past 14 years.At the same time,the implementation of the policies optimized the land use/cover pattern in the region and further affected regional ecosystem services.During the 14 years,changes in regional ecosystem services were greatly affected by vegetation coverage,wind speed,and number of days with strong winds,and the correlation coefficients were all above 0.5.In terms of precipitation,only the amount of carbon sequestered is positively related to the annual average precipitation.It can be seen that precipitation promotes the growth of vegetation.The increase of vegetation biomass is one of the main reasons for the increase of regional carbon sequestration.In terms of vegetation coverage,the wind erosion modulus,dust weather days and PM2.5 concentration were negatively correlated with normalized difference vegetation index(NDVI),and the carbon fixation was positively correlated with NDVI.The increase in vegetation coverage not only increased the carbon sequestration of vegetation and soil,but also it can suppress dust weather and wind erosion.In the aspect of wind factor,the wind erosion modulus and dust weather days are positively correlated with the annual average wind speed and the number of days with strong winds,and the carbon sequestration is negatively correlated with the annual average wind speed and the number of days with strong winds.Wind erosion are closely related to the dry and windy climate.The increase of wind days and wind speed is one of the causes of soil wind erosion.The reduction of wind speed has a significant effect on reducing wind erosion.Wind speed is the driving force behind dust weather.The number of days of strong winds and days of dusty dust tend to be positively correlated.When the number of windy weathers decreases,the frequency of sandstorms will also decrease.At the same time,vegetation growth and vegetation coverage in sandy land will be greatly affected by wind speed and number of days of strong winds.The weakening of the wind speed in the growing season can make the extremely low coverage area in the sand shift to the low and middle coverage areas,and vice versa.The conclusions of this study provide some reference and significance for the restoration and reconstruction of ecosystem functions in the Mu Us Sandy Land.Even provide a certain theoretical basis for the sustainable development of arid and semi-arid regions.