Dynamic Response Of Vegetation Ecological Service Function To Climate Change On The Loess Plateau

Ecological services functions of vegetation play a significant role in improving the environment,mitigating global warming,and enhancing human well-being.Currently,numerous studies on vegetation ecological have been conducted globally.However,most of these studies employ semi-empirical models and lack descriptions of mechanism processes,which cannot accurately predict vegetation ecological service functions under future climate change.To address this issue,this study takes the typical ecological fragile area of the Loess Plateau in China as an example.Based on the LPJ-GUESS(Lund-Potsdam-Jena General Ecosystem simulator)model,linear regression analysis,and partial correlation analysis,this study simulates and analyzes the spatiotemporal patterns of vegetation,the spatiotemporal evolution and trends of carbon storage,soil conservation,and water yield functions of vegetation from 2001 to 2100.It also examines the trade-off and synergistic relationships among various vegetation ecological services functions.These results provide a basis for developing adaptive vegetation management and high-quality development in the region under climate change.The main research conclusions are as follows:(1)The LPJ-GUESS model simulated GPP,ET,and LAI data from 2001 to 2020,and the average determination coefficient obtained by linear regression between GPP(Gross Primary Productivity),ET(Evapotranspiration),and LAI(Leaf Area Index)data from MODIS products was 0.77,and the average Nash efficiency coefficient was 0.53.The model performance was considered acceptable.(2)From 2081 to 2100,relative to 2001-2020,1.79% of shrub and 1.04% of grass were converted into forest,mainly distributed in the Lvliang and Taihang Mountains under the SSP119 scenario.It is expected that 7.77% of forest,6.28% of shrub,and 76.46% of bare land will be converted into grass,among which the areas where forest are converted to grass are mainly concentrated in the Lvliang Mountain area,the areas where shrub are converted to grass are mainly concentrated in the forest-grass transition zone,and the areas where bare land is converted to grass are mainly concentrated on the eastern edge of the Qilian Mountains.Under the SSP585 scenario,it is expected that all the bare land in the western high-altitude area will be converted into grass,and 2.69% of shrub and 2.68% of grass in the Lvliang Mountain area will be converted into forest from 2081 to 2100.(3)From 2001 to 2100,the spatial distribution of vegetation carbon storage,soil conservation,and water yield functions presents an overall "high in the southeast and low in the northwest" pattern.Under the SSP119 scenario,temperate deciduous broad-leaved forests have the highest carbon storage,soil conservation,and water yield functions from 2021 to2100.Under the SSP585 scenario,temperate evergreen coniferous forests have the highest carbon storage and water yield functions,while temperate deciduous broad-leaved forests have the highest soil conservation function.Compared with the period from 2001 to 2020,the vegetation carbon storage,soil conservation,and water yield functions have decreased in highaltitude areas in the west,while they have increased significantly in the east from 2081 to 2100.(4)From 2021 to 2100,the regions where vegetation carbon storage function significantly increases are concentrated in high-altitude areas in the west and small parts of the east,while the regions where it significantly decreases are concentrated in the south.The regions where vegetation soil conservation function significantly increases are concentrated in the west,while those where it significantly decreases are concentrated in scattered areas in the central region.The regions where vegetation water yield function significantly increases are concentrated in the west and south,while those where it significantly decreases are concentrated in scattered areas in the southeast under the SSP119 scenario.Under the SSP585 scenario,the regions where vegetation carbon storage function significantly increases are concentrated in most areas of the west,east and north,while those where it significantly decreases are concentrated in the south.The regions where vegetation soil conservation function significantly increases are concentrated in most areas of the north,and no significant decrease area was detected.The regions where vegetation water yield function significantly increases are concentrated in the northeast,southeast and west,while it significantly decreases are concentrated in high-altitude areas in the west.(5)Under the SSP119 scenario,the areas where significant changes in vegetation carbon storage,soil conservation,and water yield functions from 2021 to 2100 are 49.30%,43.91%,and 46.78%,respectively.The years of significant changes for temperate evergreen coniferous forests,temperate deciduous broad-leaved forests,and grass are 2054-2057,2052-2053,and2054-2059,respectively.Under the SSP585 scenario,the areas where significant changes occur in vegetation carbon storage,soil conservation,and water yield functions are 72.45%,51.72%,and 49.27%,respectively.The periods of significant changes in temperate evergreen coniferous forests,temperate deciduous broad-leaved forests and grass are 2062-2073,2070-2081 and 2065-2070,respectively.(6)During 2081-2100,the proportion of the significantly trade-off areas for vegetation carbon storage and water yield functions will decrease,while the proportion of significantly synergistic areas for vegetation soil conservation and water yield functions will increase,and the proportion of significantly trade-off areas for vegetation soil conservation and water yield functions will increase under the SSP119 scenario compared with 2001-2020.Under the SSP585 scenario,the proportion of significantly synergistic areas for vegetation carbon storage and water yield functions will increase,the proportion of significantly weighted areas for vegetation soil conservation and water yield functions will increase,and the proportion of significantly synergistic areas for vegetation carbon storage and soil conservation functions will decrease.Under the SSP119 scenario,the significant regions where vegetation carbon storage and water yield functions are trade-off,soil conservation and water yield functions are synergistic,and carbon storage and soil conservation functions are synergistic are mainly distributed in areas(9.03%)such as the Ordos Plateau and Liupan Mountains.Under the SSP585 scenario,the significant regions where vegetation carbon storage and water yield functions are synergistic,soil conservation and water yield functions are trade-off,and carbon storage and soil conservation functions are synergistic are mainly distributed in areas such as the eastern edge of the Qilian Mountains and the Mu Us Desert(3.36%).