Study On Spatial Simulation Of Ecosystem Services Based On Potential NPP

Ecosystem services are all kinds of products and benefits that human beings obtain directly or indirectly from the ecosystem.It is closely related to human welfare and is the basis of human survival and development.Quantitative research on ecosystem services is helpful to balance the relationship between human economic and social activities and natural environment.It is an important step to implement the path of sustainable development.And the potential ecosystem services divorced from human activities are studied research.Not only can it reflect the long-term adaptation and sensitivity of the ecological environment to climate factors,but also provide scientific reference for the implementation of ecological practice activities and ecological engineering measures such as ecosystem restoration,rational use of resources and solid enhancement of ecosystem services,and provide new ideas for the study of ecosystem services.In this paper,meteorological data,land use data,MODIS remote sensing data and vegetation type data from 2000 to 2020 were used.Based on the improved CASA model,the spatial distribution of potential vegetation NPP in China is simulated through the calculation of FPAR,and further estimate the potential carbon and oxygen fixation services and the potential wind and sand fixation services.The distribution characteristics and differences of ecosystem services under potential and actual conditions were analyzed.Finally,the difference between potential and actual ecosystem services is obtained by subtraction,which is regarded as the potential of the region to provide more ecosystem services,and is taken into account in the identification process of priority areas for ecosystem service improvement.The results indicate that:(1)There are significant spatial differences in NPP of potential vegetation in China from 2000 to 2020.The overall trend of potential vegetation NPP is increasing from northwest to southeast.The annual mean potential NPP is 663.62 g C/m~2.The high value areas are mainly areas with higher temperature,abundant precipitation and less evapotranspiration.The low value area is mainly in the northwest.Provinces with higher potential NPP are Hainan,Taiwan and Yunnan,and the lowest is Xinjiang.The potential NPP increases with the increase of longitude and decreases with the increase of latitude.According to the difference rate between potential NPP and actual NPP,the current situation of NPP in the study area can be roughly divided into three regions:the southern non-potential region,the western high-potential region and the northern low-potential region.(2)From 2000 to 2020,the potential ecosystem services in different regions vary greatly in space.The low potential oxygen release is mainly distributed in the northwest desert area of China.The areas with high potential carbon fixation and oxygen release were mainly distributed in Yichun,Mudanjiang,Greater Khingan Mountains,Sipsongpanna,Brahmaputra and Qinling Mountains-Huaihe River Line.The provinces with lower average potential carbon fixation and oxygen release were Xinjiang,Inner Mongolia,Qinghai and Gansu.The provinces with higher average potential carbon fixation and oxygen release were Hainan,Taiwan,Yunnan and Fujian.In general,the areas with low potential wind prevention and sand fixation service ability index are mainly located in the arid and semi-arid regions of northwest China,the northeastern plains and the northern plains.The areas with high potential wind prevention and sand fixation service ability index are mainly located in the southernmost part of Tibet,Yunnan,Taiwan,the Hengduan Mountains and the area around the Sichuan Basin in China.In terms of provincial administrative divisions,Sichuan,Taiwan and Yunnan provinces ranked high in terms of average potential wind prevention and sand fixation service ability index.The potential wind prevention and sand fixation service ability index of Shanghai,Jiangsu,Tianjin and Shandong provinces are very low.(3)Potential ecosystem services differ greatly from actual ecosystem services at different levels.The stratum with the largest share of potential carbon sequestration and oxygen release area is the area with 2000–3000 g/m~2,while the stratum with the largest share of actual carbon sequestration and oxygen release area is the area with<500 g/m~2.The tier with the largest area share of the potential wind prevention and sand fixation service ability index is the area of 1–10,while the tier with the largest area share of the actual wind prevention and sand fixation service ability index is the area of 0–0.1.The difference in the national contribution of potential and actual ecosystem services among provincial administrative regions shows that:Under actual conditions,the differences between ecosystem services caused by human activities in different regions will be greatly reduced under potential conditions.(4)The priority areas for improving ecosystem service functions are relatively concentrated at all levels.The primary and secondary priority protection areas for the improvement of ecosystem service function are mainly distributed in the northeast of Inner Mongolia,Changbai Mountain area,Qinling Mountains,Qilian Mountain area,Brahmaputra area and southern coastal areas.The non-priority areas are mainly distributed in the northwest arid region.Among the land use types in each priority area,the proportion of forest land in each level decreases as the priority level decreases,while the proportion of unused land gradually increases.The first priority areas for improving wind prevention and sand fixation services are mainly distributed in China’s Alashan League region,Altay region,and the northwest edge of the Taklimakan Desert,while non priority areas are mainly distributed in the southeast of China.As the priority level decreases,the proportion of unused land at all levels gradually decreases,while the proportion of cultivated land and forest land gradually increases.