Spatial And Temporal Changes In Typical Ecosystem Services And The Driving Forces,Tibetan Plateau,1990-2020

With the improvement of social productivity and the increase in human needs,the level of human transformation of the natural environment has also been gradually enhanced,leading to increasingly severe ecological problems.Quantitative assessment of regional ecosystem services and exploration of their influencing factors are of great significance for enhancing regional ecosystem services.The Qinghai-Tibet Plateau serves as an important ecological security barrier in China,but with climate change and economic growth,ecological problems such as soil erosion and grassland degradation have become increasingly prominent.Therefore,this study assessed the water yield service,soil conservation service,and wind erosion control service of the Qinghai-Tibet Plateau from 1990 to 2020 based on the In VEST(Integrated Valuation of Ecosystem Services and Tradeoffs)model and the RWEQ(Revised Wind Erosion Equation)model.The study analyzed the spatiotemporal variation patterns of these services and their main driving forces,and further explored the spatiotemporal changes in the total amount of ecosystem services.The main results are as follows:(1)The year 2006 was a turning point in the water yield service of the Qinghai-Tibet Plateau.In the eastern region,the water yield service decreased from 1990 to 2006,mainly due to climate warming and drying.After 2006,the water yield service increased due to climate cooling and moistening.In the central region,the increase before 2006 was mainly attributed to an increase in annual precipitation(AP),while the decrease after2006 was influenced by an increase in potential evapotranspiration(PET)and policies.The water yield service in the western region continued to increase,mainly due to an increase in AP before 2006.After 2006,the increase in water yield service in the northwest region was mainly due to climate moistening and cooling.In the southwest region,while AP decreased,PET also decreased,and some grasslands converted to deserts,resulting in an increase in water yield service.(2)The soil conservation service on the Qinghai-Tibet Plateau experienced a turning point in 2010.Before 2010,the decrease in the southeastern region was primarily due to the combined effects of decreased AP,increased Mean Annual Temperature(MAT),and increased Precipitation Concentration Index(PCI).The subsequent increase after 2010 was caused by an increase in AP and improvement in vegetation due to ecological policies.From 1990 to 2010,soil conservation in the western and northern regions was driven by climate and vegetation factors.After 2010,the decrease in soil conservation in the western and northern regions was attributed to decreased AP,Normalized Difference Vegetation Index(NDVI),increased PCI,and human activities.(3)From 1990 to 2020,the wind erosion control service on the Qinghai-Tibet Plateau increased in the southeastern and northern parts but decreased in the western part.The decrease in wind erosion control service in the western region was mainly driven by increased AP and changes in land use.In the southeastern region,the increase in wind erosion control service was primarily influenced by decreased AP,increased MAT,decreased wind speed(WS),and vegetation changes.(4)From 1990 to 2020,there was an overall improvement in the total amount of ecosystem services on the Qinghai-Tibet Plateau.The spatial pattern shifted from a concentration of high values in the central and western regions before 2000 to a dispersed trend after 2000,indicating a tendency towards balanced development of ecosystem services on the Qinghai-Tibet Plateau.In general,climate change is the main factor influencing water yield,soil conservation,and wind erosion control services in most areas of the Qinghai-Tibet Plateau.However,the impact of human activities,such as the implementation of ecological conservation policies,has also become increasingly evident in recent years.Fine-scale studies of ecosystem services contribute to understanding their complex driving mechanisms and provide guidance for the formulation and optimization of regional ecological policies.