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  - 
TY  - JOUR
A1  - Tian, Fang
A1  - Qin, Wen
A1  - Zhang, Ran
A1  - Herzschuh, Ulrike
A1  - Ni, Jian
A1  - Zhang, Chengjun
A1  - Mischke, Steffen
A1  - Cao, Xianyong
T1  - Palynological evidence for the temporal stability of the plant community in the Yellow River Source Area over the last 7,400 years
JF  - Vegetation history and archaeobotany
N2  - The terrestrial ecosystem in the Yellow River Source Area (YRSA) is sensitive to climate change and human impacts, although past vegetation change and the degree of human disturbance are still largely unknown. A 170-cm-long sediment core covering the last 7,400 years was collected from Lake Xingxinghai (XXH) in the YRSA. Pollen, together with a series of other environmental proxies (including grain size, total organic carbon (TOC) and carbonate content), were analysed to explore past vegetation and environmental changes for the YRSA. Dominant and common pollen components-Cyperaceae, Poaceae, Artemisia, Chenopodiaceae and Asteraceae-are stable throughout the last 7,400 years. Slight vegetation change is inferred from an increasing trend of Cyperaceae and decreasing trend of Poaceae, suggesting that alpine steppe was replaced by alpine meadow at ca. 3.5 ka cal bp. The vegetation transformation indicates a generally wetter climate during the middle and late Holocene, which is supported by increased amounts of TOC and Pediastrum (representing high water-level) and is consistent with previous past climate records from the north-eastern Tibetan Plateau. Our results find no evidence of human impact on the regional vegetation surrounding XXH, hence we conclude the vegetation change likely reflects the regional climate signal.
KW  - Pollen
KW  - Lake Xingxinghai
KW  - Tibetan Plateau
KW  - Holocene
KW  - Vegetation change
KW  - Regional climate
Y1  - 2022
U6  - https://doi.org/10.1007/s00334-022-00870-5
SN  - 0939-6314
SN  - 1617-6278
VL  - 31
IS  - 6
SP  - 549
EP  - 558
PB  - Springer
CY  - New York
ER  - 
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  - GEN
A1  - Cao, Xianyong
A1  - Tian, Fang
A1  - Andreev, Andrei
A1  - Anderson, Patricia M.
A1  - Lozhkin, Anatoly V.
A1  - Bezrukova, Elena
A1  - Ni, Jian
A1  - Rudaya, Natalia
A1  - Stobbe, Astrid
A1  - Wieczorek, Mareike
A1  - Herzschuh, Ulrike
T1  - A taxonomically harmonized and temporally standardized fossil pollen dataset from Siberia covering the last 40 kyr
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Pollen records from Siberia are mostly absent in global or Northern Hemisphere synthesis works. Here we present a taxonomically harmonized and temporally standardized pollen dataset that was synthesized using 173 palynological records from Siberia and adjacent areas (northeastern Asia, 42-75 degrees N, 50-180 degrees E). Pollen data were taxonomically harmonized, i.e. the original 437 taxa were assigned to 106 combined pollen taxa. Age-depth models for all records were revised by applying a constant Bayesian age-depth modelling routine. The pollen dataset is available as count data and percentage data in a table format (taxa vs. samples), with age information for each sample. The dataset has relatively few sites covering the last glacial period between 40 and 11.5 ka (calibrated thousands of years before 1950 CE) particularly from the central and western part of the study area. In the Holocene period, the dataset has many sites from most of the area, with the exception of the central part of Siberia. Of the 173 pollen records, 81 % of pollen counts were downloaded from open databases (GPD, EPD, PANGAEA) and 10 % were contributions by the original data gatherers, while a few were digitized from publications. Most of the pollen records originate from peatlands (48 %) and lake sediments (33 %). Most of the records (83 %) have >= 3 dates, allowing the establishment of reliable chronologies. The dataset can be used for various purposes, including pollen data mapping (example maps for Larix at selected time slices are shown) as well as quantitative climate and vegetation reconstructions. The datasets for pollen counts and pollen percentages are available at https://doi.org/10.1594/PANGAEA.898616 (Cao et al., 2019a), also including the site information, data source, original publication, dating data, and the plant functional type for each pollen taxa.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1427 
KW  - Late Quaternary vegetation
KW  - Holocene environmental history
KW  - eastern continental Asia
KW  - plant macrofossil data
KW  - late pleistocene
KW  - paleoenvironmental records
KW  - Verkhoyansk mountains
KW  - climate dynamics
KW  - glacial maximum
KW  - Northern Asia
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-512438
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Cao, Xianyong
A1  - Tian, Fang
A1  - Andreev, Andrei
A1  - Anderson, Patricia M.
A1  - Lozhkin, Anatoly V.
A1  - Bezrukova, Elena
A1  - Ni, Jian
A1  - Rudaya, Natalia
A1  - Stobbe, Astrid
A1  - Wieczorek, Mareike
A1  - Herzschuh, Ulrike
T1  - A taxonomically harmonized and temporally standardized fossil pollen dataset from Siberia covering the last 40 kyr
JF  - Earth System Science Data
N2  - Pollen records from Siberia are mostly absent in global or Northern Hemisphere synthesis works. Here we present a taxonomically harmonized and temporally standardized pollen dataset that was synthesized using 173 palynological records from Siberia and adjacent areas (northeastern Asia, 42-75 degrees N, 50-180 degrees E). Pollen data were taxonomically harmonized, i.e. the original 437 taxa were assigned to 106 combined pollen taxa. Age-depth models for all records were revised by applying a constant Bayesian age-depth modelling routine. The pollen dataset is available as count data and percentage data in a table format (taxa vs. samples), with age information for each sample. The dataset has relatively few sites covering the last glacial period between 40 and 11.5 ka (calibrated thousands of years before 1950 CE) particularly from the central and western part of the study area. In the Holocene period, the dataset has many sites from most of the area, with the exception of the central part of Siberia. Of the 173 pollen records, 81 % of pollen counts were downloaded from open databases (GPD, EPD, PANGAEA) and 10 % were contributions by the original data gatherers, while a few were digitized from publications. Most of the pollen records originate from peatlands (48 %) and lake sediments (33 %). Most of the records (83 %) have >= 3 dates, allowing the establishment of reliable chronologies. The dataset can be used for various purposes, including pollen data mapping (example maps for Larix at selected time slices are shown) as well as quantitative climate and vegetation reconstructions. The datasets for pollen counts and pollen percentages are available at https://doi.org/10.1594/PANGAEA.898616 (Cao et al., 2019a), also including the site information, data source, original publication, dating data, and the plant functional type for each pollen taxa.
KW  - Late Quaternary vegetation
KW  - Holocene environmental history
KW  - eastern continental Asia
KW  - plant macrofossil data
KW  - late pleistocene
KW  - paleoenvironmental records
KW  - Verkhoyansk mountains
KW  - climate dynamics
KW  - glacial maximum
KW  - Northern Asia
Y1  - 2020
U6  - https://doi.org/10.5194/essd-12-119-2020
SN  - 1866-3508
SN  - 1866-3516
VL  - 12
IS  - 1
SP  - 119
EP  - 135
PB  - Copernics Publications
CY  - Katlenburg-Lindau
ER  - 
TY  - JOUR
A1  - Jia, Weihan
A1  - Anslan, Sten
A1  - Chen, Fahu
A1  - Cao, Xianyong
A1  - Dong, Hailiang
A1  - Dulias, Katharina
A1  - Gu, Zhengquan
A1  - Heinecke, Liv
A1  - Jiang, Hongchen
A1  - Kruse, Stefan
A1  - Kang, Wengang
A1  - Li, Kai
A1  - Liu, Sisi
A1  - Liu, Xingqi
A1  - Liu, Ying
A1  - Ni, Jian
A1  - Schwalb, Antje
A1  - Stoof-Leichsenring, Kathleen R.
A1  - Shen, Wei
A1  - Tian, Fang
A1  - Wang, Jing
A1  - Wang, Yongbo
A1  - Wang, Yucheng
A1  - Xu, Hai
A1  - Yang, Xiaoyan
A1  - Zhang, Dongju
A1  - Herzschuh, Ulrike
T1  - Sedimentary ancient DNA reveals past ecosystem and biodiversity changes on the Tibetan Plateau: overview and prospects
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era.
KW  - Sedimentary ancient DNA (sedaDNA)
KW  - Tibetan Plateau
KW  - Environmental DNA
KW  - Taphonomy
KW  - Ecosystem
KW  - Biodiversity
KW  - Paleoecology
KW  - Paleogeography
Y1  - 2022
U6  - https://doi.org/10.1016/j.quascirev.2022.107703
SN  - 0277-3791
SN  - 1873-457X
VL  - 293
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Tian, Fang
A1  - Cao, Xianyong
A1  - Dallmeyer, Anne
A1  - Zhao, Yan
A1  - Ni, Jian
A1  - Herzschuh, Ulrike
T1  - Pollen-climate relationships in time (9 ka, 6 ka, 0 ka) and space (upland vs. lowland) in eastern continental Asia
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Temporal and spatial stability of the vegetation climate relationship is a basic ecological assumption for pollen-based quantitative inferences of past climate change and for predicting future vegetation. We explore this assumption for the Holocene in eastern continental Asia (China, Mongolia). Boosted regression trees (BRT) between fossil pollen taxa percentages (Abies, Artemisia, Betula, Chenopodiaceae, Cyperaceae, Ephedra, Picea, Pinus, Poaceae and Quercus) and climate model outputs of mean annual precipitation (P-ann) and mean temperature of the warmest month (Mt(wa)) for 9 and 6 ka (ka = thousand years before present) were set up and results compared to those obtained from relating modern pollen to modern climate. Overall, our results reveal only slight temporal differences in the pollen climate relationships. Our analyses suggest that the importance of P-ann compared with Mt(wa) for taxa distribution is higher today than it was at 6 ka and 9 ka. In particular, the relevance of P-ann for Picea and Pinus increases and has become the main determinant. This change in the climate tree pollen relationship parallels a widespread tree pollen decrease in north-central China and the eastern Tibetan Plateau. We assume that this is at least partly related to vegetation climate disequilibrium originating from human impact. Increased atmospheric CO2 concentration may have permitted the expansion of moisture-loving herb taxa (Cyperaceae and Poaceae) during the late Holocene into arid/semi-arid areas. We furthermore find that the pollen climate relationship between north-central China and the eastern Tibetan Plateau is generally similar, but that regional differences are larger than temporal differences. In summary, vegetation climate relationships in China are generally stable in space and time, and pollen-based climate reconstructions can be applied to the Holocene. Regional differences imply the calibration-set should be restricted spatially.
KW  - Boosted regression trees
KW  - China
KW  - Holocene
KW  - Niche stability
KW  - Pollen-climate relationship
KW  - Uniformitarianism
Y1  - 2016
U6  - https://doi.org/10.1016/j.quascirev.2016.11.027
SN  - 0277-3791
VL  - 156
SP  - 1
EP  - 11
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Tian, Fang
A1  - Cao, Xianyong
A1  - Dallmeyer, Anne
A1  - Lohmann, Gerrit
A1  - Zhang, Xu
A1  - Ni, Jian
A1  - Andreev, Andrei
A1  - Anderson, Patricia M.
A1  - Lozhkin, Anatoly V.
A1  - Bezrukova, Elena
A1  - Rudaya, Natalia
A1  - Xu, Qinghai
A1  - Herzschuh, Ulrike
T1  - Biome changes and their inferred climatic drivers in northern and eastern continental Asia at selected times since 40 cal ka BP
JF  - Vegetation History and Archaeobotany
N2  - Recent global warming is pronounced in high-latitude regions (e.g. northern Asia), and will cause the vegetation to change. Future vegetation trends (e.g. the "arctic greening") will feed back into atmospheric circulation and the global climate system. Understanding the nature and causes of past vegetation changes is important for predicting the composition and distribution of future vegetation communities. Fossil pollen records from 468 sites in northern and eastern Asia were biomised at selected times between 40 cal ka bp and today. Biomes were also simulated using a climate-driven biome model and results from the two approaches compared in order to help understand the mechanisms behind the observed vegetation changes. The consistent biome results inferred by both approaches reveal that long-term and broad-scale vegetation patterns reflect global- to hemispheric-scale climate changes. Forest biomes increase around the beginning of the late deglaciation, become more widespread during the early and middle Holocene, and decrease in the late Holocene in fringe areas of the Asian Summer Monsoon. At the southern and southwestern margins of the taiga, forest increases in the early Holocene and shows notable species succession, which may have been caused by winter warming at ca. 7 cal ka bp. At the northeastern taiga margin (central Yakutia and northeastern Siberia), shrub expansion during the last deglaciation appears to prevent the permafrost from thawing and hinders the northward expansion of evergreen needle-leaved species until ca. 7 cal ka bp. The vegetation-climate disequilibrium during the early Holocene in the taiga-tundra transition zone suggests that projected climate warming will not cause a northward expansion of evergreen needle-leaved species.
KW  - Siberia
KW  - China
KW  - Northern Asia
KW  - Model-data comparison
KW  - Pollen
KW  - Permafrost
KW  - Vegetation-climate disequilibrium
Y1  - 2018
U6  - https://doi.org/10.1007/s00334-017-0653-8
SN  - 0939-6314
SN  - 1617-6278
VL  - 27
IS  - 2
SP  - 365
EP  - 379
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Herzschuh, Ulrike
A1  - Cao, Xianyong
A1  - Laepple, Thomas
A1  - Dallmeyer, Anne
A1  - Telford, Richard J.
A1  - Ni, Jian
A1  - Chen, Fahu
A1  - Kong, Zhaochen
A1  - Liu, Guangxiu
A1  - Liu, Kam-Biu
A1  - Liu, Xingqi
A1  - Stebich, Martina
A1  - Tang, Lingyu
A1  - Tian, Fang
A1  - Wang, Yongbo
A1  - Wischnewski, Juliane
A1  - Xu, Qinghai
A1  - Yan, Shun
A1  - Yang, Zhenjing
A1  - Yu, Ge
A1  - Zhang, Yun
A1  - Zhao, Yan
A1  - Zheng, Zhuo
T1  - Position and orientation of the westerly jet determined Holocene rainfall patterns in China
JF  - Nature Communications
N2  - Proxy-based reconstructions and modeling of Holocene spatiotemporal precipitation patterns for China and Mongolia have hitherto yielded contradictory results indicating that the basic mechanisms behind the East Asian Summer Monsoon and its interaction with the westerly jet stream remain poorly understood. We present quantitative reconstructions of Holocene precipitation derived from 101 fossil pollen records and analyse them with the help of a minimal empirical model. We show that the westerly jet-stream axis shifted gradually southward and became less tilted since the middle Holocene. This was tracked by the summer monsoon rain band resulting in an early-Holocene precipitation maximum over most of western China, a mid-Holocene maximum in north-central and northeastern China, and a late-Holocene maximum in southeastern China. Our results suggest that a correct simulation of the orientation and position of the westerly jet stream is crucial to the reliable prediction of precipitation patterns in China and Mongolia.
Y1  - 2019
U6  - https://doi.org/10.1038/s41467-019-09866-8
SN  - 2041-1723
VL  - 10
PB  - Nature Publ. Group
CY  - London
ER  -