TY  - JOUR
A1  - Li, Wenjia
A1  - Tian, Fang
A1  - Rudaya, Natalya A.
A1  - Herzschuh, Ulrike
A1  - Cao, Xianyong
T1  - Pollen-based holocene thawing-history of permafrost in Northern Asia and its potential impacts on climate change
JF  - Frontiers in Ecology and Evolution
N2  - As the recent permafrost thawing of northern Asia proceeds due to anthropogenic climate change, precise and detailed palaeoecological records from past warm periods are essential to anticipate the extent of future permafrost variations. Here, based on the modern relationship between permafrost and vegetation (represented by pollen assemblages), we trained a Random Forest model using pollen and permafrost data and verified its reliability to reconstruct the history of permafrost in northern Asia during the Holocene. An early Holocene (12-8 cal ka BP) strong thawing trend, a middle-to-late Holocene (8-2 cal ka BP) relatively slow thawing trend, and a late Holocene freezing trend of permafrost in northern Asia are consistent with climatic proxies such as summer solar radiation and Northern Hemisphere temperature. The extensive distribution of permafrost in northern Asia inhibited the spread of evergreen coniferous trees during the early Holocene warming and might have decelerated the enhancement of the East Asian summer monsoon (EASM) by altering hydrological processes and albedo. Based on these findings, we suggest that studies of the EASM should consider more the state of permafrost and vegetation in northern Asia, which are often overlooked and may have a profound impact on climate change in this region.
KW  - pollen
KW  - Random Forest
KW  - Siberia
KW  - East Asian summer monsoon
KW  - permafrost
Y1  - 2022
U6  - https://doi.org/10.3389/fevo.2022.894471
SN  - 2296-701X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Cao, Xianyong
A1  - Chen, Jianhui
A1  - Tian, Fang
A1  - Xu, Qinghai
A1  - Herzschuh, Ulrike
A1  - Telford, Richard
A1  - Huang, Xiaozhong
A1  - Zheng, Zhuo
A1  - Shen, Caiming
A1  - Li, Wenjia
T1  - Long-distance modern analogues bias results of pollen-based precipitation reconstructions
JF  - Science bulletin
Y1  - 2022
U6  - https://doi.org/10.1016/j.scib.2022.01.003
SN  - 2095-9273
SN  - 2095-9281
VL  - 67
IS  - 11
SP  - 1115
EP  - 1117
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Cao, Xianyong
A1  - Tian, Fang
A1  - Herzschuh, Ulrike
A1  - Ni, Jian
A1  - Xu, Qinghai
A1  - Li, Wenjia
A1  - Zhang, Yanrong
A1  - Luo, Mingyu
A1  - Chen, Fahu
T1  - Human activities have reduced plant diversity in eastern China over the last two millennia
JF  - Global change biology
N2  - Understanding the history and regional singularities of human impact on vegetation is key to developing strategies for sustainable ecosystem management. In this study, fossil and modern pollen datasets from China are employed to investigate temporal changes in pollen composition, analogue quality, and pollen diversity during the Holocene. Anthropogenic disturbance and vegetation's responses are also assessed. Results reveal that pollen assemblages from non-forest communities fail to provide evidence of human impact for the western part of China (annual precipitation less than 400 mm and/or elevation more than 3000 m.a.s.l.), as inferred from the stable quality of modern analogues, principal components, and diversity of species and communities throughout the Holocene. For the eastern part of China, the proportion of fossil pollen spectra with good modern analogues increases from ca. 50% to ca. 80% during the last 2 millennia, indicating an enhanced intensity of anthropogenic disturbance on vegetation. This disturbance has caused the pollen spectra to become taxonomically less diverse over space (reduced abundances of arboreal taxa and increased abundances of herbaceous taxa), highlighting a reduced south-north differentiation and divergence from past vegetation between regions in the eastern part of China. We recommend that care is taken in eastern China when basing the development of ecosystem management strategies on vegetation changes in the region during the last 2000 years, since humans have significantly disturbed the vegetation during this period.
KW  - analogue quality
KW  - human-vegetation interaction
KW  - land use
KW  - latitudinal
KW  - zonation
KW  - plant diversity
KW  - pollen
Y1  - 2022
U6  - https://doi.org/10.1111/gcb.16274
SN  - 1354-1013
SN  - 1365-2486
VL  - 28
IS  - 16
SP  - 4962
EP  - 4976
PB  - Wiley
CY  - Hoboken
ER  -