Dataset Information

Pollen record of climate change during the last deglaciation from the eastern Tibetan Plateau.

ABSTRACT: The eastern Tibetan Plateau (TP) is a climatically sensitive area affected by the Indian Summer Monsoon (ISM). A new pollen record from a lacustrine sediment in Mao County shows that the study area was covered mainly by shrubs and herbs during the last deglaciation, indicating open and sparse forest grasslands. Hydrophilous herbs were mainly dominated by Cyperaceae, Poaceae, Myriophyllum, Polygonum and Typha, and they gradually increased from 18.7 to 16.8 ka, suggesting a transition to a more humid climate. This corresponds to climate cooling over the same period. From 16.8 to 14.6 ka, hydrophilous herbs continued to increase, coincident with a general ameliorating trend indicated by ?18O records from East Asia. Between 14.6 and 14.0 ka, the mean content of hydrophilous herbs reached peak in the sequence, corresponding to relatively high ?18O values during this period. From ~14.0 to 12.9 ka, the abundance of hydrophilous herbs decreased significantly. Over the same period, the Greenland ice core shows a decrease in ?18O and low-latitude cave stalagmites in China record an increase in ?18O. This implies that longitudinal temperature gradients increased and drove the southward retreat of the ISM, which in turn drove a continuous decrease in the abundance of hydrophilous herbs in the study area. From 12.9 to 11.6 ka, the mean content of hydrophilous herbs decreased to the lowest (8.3%) in the whole sequence, indicating a cold and dry climate in the study area. A positive shift in ?18O records during 11.6-10.6 ka was matched by a significant increase in the abundance of hydrophilous herbs in the study area, indicating a warm and humid climate trending. Hence, the ISM has had a significant impact on the climate of the eastern TP since the onset of deglaciation around ~16.8 ka.

SUBMITTER: Shi W

PROVIDER: S-EPMC7202599 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Pollen record of climate change during the last deglaciation from the eastern Tibetan Plateau.

Shi Wei W Jiang Hanchao H Mao Xue X Xu Hongyan H

PloS one 20200506 5

The eastern Tibetan Plateau (TP) is a climatically sensitive area affected by the Indian Summer Monsoon (ISM). A new pollen record from a lacustrine sediment in Mao County shows that the study area was covered mainly by shrubs and herbs during the last deglaciation, indicating open and sparse forest grasslands. Hydrophilous herbs were mainly dominated by Cyperaceae, Poaceae, Myriophyllum, Polygonum and Typha, and they gradually increased from 18.7 to 16.8 ka, suggesting a transition to a more hu ...[more]

PMID: 32374789

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Project description:BackgroundMonitoring vegetation dynamics and their responses to climate change has been the subject of considerable research. This paper aims to detect change trends in grassland activity on the Tibetan Plateau between 1982 and 2006 and relate these to changes in climate.Methodology/principal findingsGrassland activity was analyzed by evaluating remotely sensed Normalized Difference Vegetation Index (NDVI) data collected at 15-day intervals between 1982 and 2006. The timings of vegetation stages (start of green-up, beginning of the growing season, plant maturity, start of senescence and end of the growing season) were assessed using the NDVI ratio method. Mean NDVI values were determined for major vegetation stages (green-up, fast growth, maturity and senescence). All vegetation variables were linked with datasets of monthly temperature and precipitation, and correlations between variables were established using Partial Least Squares regression. Most parts of the Tibetan Plateau showed significantly increasing temperatures, as well as clear advances in late season phenological stages by several weeks. Rainfall trends and significant long-term changes in early season phenology occurred on small parts of the plateau. Vegetation activity increased significantly for all vegetation stages. Most of these changes were related to increasing temperatures during the growing season and in some cases during the previous winter. Precipitation effects appeared less pronounced. Warming thus appears to have shortened the growing season, while increasing vegetation activity.Conclusions/significanceShortening of the growing season despite a longer thermally favorable period implies that vegetation on the Tibetan Plateau is unable to exploit additional thermal resources availed by climate change. Ecosystem composition may no longer be well attuned to the local temperature regime, which has changed rapidly over the past three decades. This apparent lag of the vegetation assemblage behind changes in climate should be taken into account when projecting the impacts of climate change on ecosystem processes.

Dataset Information

Pollen record of climate change during the last deglaciation from the eastern Tibetan Plateau.

Publications

Pollen record of climate change during the last deglaciation from the eastern Tibetan Plateau.

Similar Datasets

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