| Forest is the most important terrestrial ecosystem,providing a wide range of irreplaceable ecosystem services and serving as a key foundation for ecological security and sustainable development.Understanding the supply level and spatial and temporal variability of ecosystem services is a key foundation for ecosystem management.However,due to the influence of climate change and human activities,the structure and function of forest ecosystems show obvious spatial and temporal variability and complexity at different scales,which still needs to be studied in depth.The Yangtze River basin is an important ecological geographic area in China and an important bearing area for the development strategy of the Yangtze River Economic Belt.The conflict between ecological protection and economic development is prominent,and human activities and climate variability are significant.The complexity and variability of its impact on the structure and function of forest ecosystems remain unclear,constraining watershed-scale ecosystem conservation and restoration decisions.This study aims to reveal the spatial and temporal variability patterns of ecosystem service provision at the watershed scale and its key drivers in the context of human activities and climate change through the study of spatial and temporal variability characteristics of key service functions of forest ecosystems in the Yangtze River basin,and to provide theoretical and data support for the integrated management of watershed ecosystems.Based on meteorological data,land use/cover data,soil data,and sociodemographic and economic data from 2000 to 2020,this study uses the In VEST and CASA models to assess three services: forest water retention,net primary productivity(NPP)of vegetation,and soil conservation in the Yangtze River basin.The characteristics of its spatial distribution and temporal dynamics were studied,and the drivers of its spatio-temporal dynamics were analyzed to reveal the characteristics of multiple service relationships and their spatial differences in distribution.The main findings revealed that:(1)Significant land use/cover type conversion characteristics were evident during2000-2018.Spatially,the main types of land use/cover in the Yangtze River Basin are forest land and cropland.In the context of ecological project implementation,forested land is on the rise,with forested land having the largest growth rate,followed by shrubland;while farmland,grassland and unused land are on the decline.The transformation of arable land to forest land is obvious,mainly in the central region of the Yangtze River Basin;in addition,the transformation of unused land to various forest land types is obvious in the southwestern region.(2)The spatial and temporal distribution of multi-year mean values of forest ecosystem services varied widely.Water conservation mainly shows a distribution trend of high southeast and low northwest,while NPP and soil conservation show a distribution characteristic of low in the northeast and northwest regions and high in the central region.In terms of land use/cover type,all present the highest values of services in forest land.In terms of multi-year series changes,all three ecosystem services show an upward trend in the total watershed.At the sub-basin scale,NPP and soil conservation showed a decreasing trend in the Taihu Lake basin.(3)The hot spot areas are mainly located in the eastern and south-central regions of the Yangtze River basin,accounting for 73.14% of the total basin area,with no obvious trend of change;The cold spot area is mainly distributed in the northwestern part of the Yangtze River basin and the eastern part of Sichuan Province,accounting for 26.86% of the total regional area.In terms of trade-offs and synergistic relationships between ecosystem service pairs,water conservation and NPP show synergistic relationships overall;soil conservation and NPP have no significant spatial correlation;while water conservation and soil conservation show strong trade-offs in the southeastern region of the Yangtze River Basin,and synergistic relationships in the north-central and western regions.(4)The dominant drivers of ecosystem services vary widely across ecosystems.The main driving factor of water conservation is precipitation,which shows significant positive correlation with precipitation and temperature,and significant negative correlation with solar radiation and slope.NPP was highly significantly and positively correlated with temperature,precipitation,potential evapotranspiration,and mean elevation,but the correlation coefficient was small.Soil conservation showed a highly significant positive correlation with elevation.On sub-basin regions,some regional ecosystem services show a negative correlation with socio-demographic and economic factors.Especially in the Taihu Lake basin,all three ecosystem services were significantly and negatively correlated with population density and nighttime lights.(5)This study provides a comprehensive and systematic assessment of regional ecosystem service functions in the Yangtze River basin,which not only quantifies the spatial evolution patterns and interannual variation trends of three ecosystem service functions,but also can provide data support and reference for the future implementation and planning of forest projects in the Yangtze River basin. |
PDF Full Text Request