Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau(CLP). This study presents analyses of ...Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau(CLP). This study presents analyses of total organic carbon isotopic composition(TOC) and n-alkane ratios(C31/C27) from the Lingtai loess-palaeosol sequence on the central CLP over the last 450 kyr. The results demonstrate that the vegetation in this region comprised a mix of C_3 and C_4 plants of herb and woody growth-form. C_3 plants dominated for most of the last 450 kyr, but this did not lead to extensive forest. C_3 woody plants were more abundant in MIS9(S3 period) and MIS5(S1 period) during warm and humid climate conditions. Herbs increased in the region since 130 kyr, possibly as a result of increased aridity. On the orbital timescales, there was a reduction of C_3 herbal plants in MIS11(S4) than in MIS12(L5), and in Holocene than in the last glacial period. Our isotope and n-alkane proxy records are in agreement with Artemisia pollen changes in the region, which is/was the dominant species in this area and varying due to different heat and water conditions between glacial and interglacial periods. Though the climate in MIS1(S0) was similar to that in MIS11(S4), a significant increase in woody plants during the Holocene suggests the impact of human activities and ecological effects of changes in fire activity.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41172149)the Science Fund for Creative Research Groups of NSFC(Grant No.41321062)the National Key Basic Research Program of China(Grant No.2015CB953804)
文摘Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau(CLP). This study presents analyses of total organic carbon isotopic composition(TOC) and n-alkane ratios(C31/C27) from the Lingtai loess-palaeosol sequence on the central CLP over the last 450 kyr. The results demonstrate that the vegetation in this region comprised a mix of C_3 and C_4 plants of herb and woody growth-form. C_3 plants dominated for most of the last 450 kyr, but this did not lead to extensive forest. C_3 woody plants were more abundant in MIS9(S3 period) and MIS5(S1 period) during warm and humid climate conditions. Herbs increased in the region since 130 kyr, possibly as a result of increased aridity. On the orbital timescales, there was a reduction of C_3 herbal plants in MIS11(S4) than in MIS12(L5), and in Holocene than in the last glacial period. Our isotope and n-alkane proxy records are in agreement with Artemisia pollen changes in the region, which is/was the dominant species in this area and varying due to different heat and water conditions between glacial and interglacial periods. Though the climate in MIS1(S0) was similar to that in MIS11(S4), a significant increase in woody plants during the Holocene suggests the impact of human activities and ecological effects of changes in fire activity.
