SPATIOTEMPORAL CHANGES IN C4 PLANT ABUNDANCE AND THEIR DRIVING FACTORS IN THE NORTHEAST CHINA AND ADJACENT AREAS SINCE THE LAST GLACIAL MAXIMUM
C3 and C4 plants are the fundamental part of the terrestrial ecosystem.The global climate system has experienced an overall warming trend since the Last Glacial Maximum(LGM)accompanied by constant changes in atmospheric CO2 concentration.Knowledge of the spatiotemporal pattern of C3 and C4 plants and their response to climate change since the LGM,is important for predicting the biosphere's response to future climatic warming.Here,the Northeast(NE)China and adjacent areas are located in the marginal zone of the region of influence of the East Asian summer monsoon(EASM),including Heilongjiang,Jilin,Liaoning provinces,and the northeast part of Inner Mongolia,with a mixed zone of C3 and C4 plants.It is therefore extremely sensitive to changes in climate.In this study,we reconstructed the spatiotemporal pattern of C4 plants in NE China and adjacent areas since the LGM,based on a synthesis of δ13C records of soil organic matter from 4 paleosol sequences and δ13C records of individual n-alkanes from 9 lake sediment sequences.The results indicate that the relative abundance of C4 plants increased after the LGM,reaching a maximum(average by about 10％)during Early-Middle Holocene,and then decreased.There was a difference in the temporal evolution of C4 plant abundance between the east and west parts of the boundary of forest and steppe.C4 plant abundance in the east parts indicated a decrease since the Holocene,while a relative stable change in west part during the Holocene.Spatially,the representation of C4 plants was characterized by increasing values from north to south.In addition,the smallest spatial difference(5％)in the representation of C4 plants between the north-west and south-east parts of NE China was during the LGM,and the largest spatial difference(20％)was during the Early Holocene.Comparing our results with the changes in climate and atmospheric CO2 concentration,the results suggest that increasing temperature was the dominant factor driving C4 plant expansion in NE China since the LGM.This may indicate the global warming would have benefited the development of C4 plant in NE China in future.
万方数据
维普
