TY - GEN A1 - Cao, Xianyong A1 - Herzschuh, Ulrike A1 - Ni, Jian A1 - Zhao, Yan A1 - Böhmer, Thomas T1 - Spatial and temporal distributions of major tree taxa in eastern continental Asia during the last 22,000 years T2 - The Holocene N2 - This study investigates the spatial and temporal distributions of 14 key arboreal taxa and their driving forces during the last 22,000 calendar years before ad 1950 (kyr BP) using a taxonomically harmonized and temporally standardized fossil pollen dataset with a 500-year resolution from the eastern part of continental Asia. Logistic regression was used to estimate pollen abundance thresholds for vegetation occurrence (presence or dominance), based on modern pollen data and present ranges of 14 taxa in China. Our investigation reveals marked changes in spatial and temporal distributions of the major arboreal taxa. The thermophilous (Castanea, Castanopsis, Cyclobalanopsis, Fagus, Pterocarya) and eurythermal (Juglans, Quercus, Tilia, Ulmus) broadleaved tree taxa were restricted to the current tropical or subtropical areas of China during the Last Glacial Maximum (LGM) and spread northward since c. 14.5 kyr BP. Betula and conifer taxa (Abies, Picea, Pinus), in contrast, retained a wider distribution during the LGM and showed no distinct expansion direction during the Late Glacial. Since the late mid-Holocene, the abundance but not the spatial extent of most trees decreased. The changes in spatial and temporal distributions for the 14 taxa are a reflection of climate changes, in particular monsoonal moisture, and, in the late Holocene, human impact. The post-LGM expansion patterns in eastern continental China seem to be different from those reported for Europe and North America, for example, the westward spread for eurythermal broadleaved taxa. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 417 KW - China KW - Holocene KW - Last Glacial Maximum KW - pollen mapping KW - vegetation expansion Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404176 VL - 25 IS - 1 ER - TY - JOUR A1 - Herzschuh, Ulrike A1 - Böhmer, Thomas A1 - Li, Chenzhi A1 - Cao, Xianyong A1 - Hébert, Raphaël A1 - Dallmeyer, Anne A1 - Telford, Richard J. A1 - Kruse, Stefan T1 - Reversals in temperature-precipitation correlations in the Northern Hemisphere extratropics during the Holocene JF - Geophysical research letters N2 - Future precipitation levels remain uncertain because climate models have struggled to reproduce observed variations in temperature-precipitation correlations. Our analyses of Holocene proxy-based temperature-precipitation correlations and hydrological sensitivities from 2,237 Northern Hemisphere extratropical pollen records reveal a significant latitudinal dependence and temporal variations among the early, middle, and late Holocene. These proxy-based variations are largely consistent with patterns obtained from transient climate simulations (TraCE21k). While high latitudes and subtropical monsoon areas show mainly stable positive correlations throughout the Holocene, the mid-latitude pattern is temporally and spatially more variable. In particular, we identified a reversal from positive to negative temperature-precipitation correlations in the eastern North American and European mid-latitudes from the early to mid-Holocene that mainly related to slowed down westerlies and a switch to moisture-limited convection under a warm climate. Our palaeoevidence of past temperature-precipitation correlation shifts identifies those regions where simulating past and future precipitation levels might be particularly challenging. Y1 - 2022 U6 - https://doi.org/10.1029/2022GL099730 SN - 0094-8276 SN - 1944-8007 VL - 49 IS - 22 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Cao, Xianyong A1 - Herzschuh, Ulrike A1 - Ni, Jian A1 - Zhao, Yan A1 - Böhmer, Thomas T1 - Spatial and temporal distributions of major tree taxa in eastern continental Asia during the last 22,000 years JF - The Holocene : an interdisciplinary journal focusing on recent environmental change N2 - This study investigates the spatial and temporal distributions of 14 key arboreal taxa and their driving forces during the last 22,000 calendar years before ad 1950 (kyr BP) using a taxonomically harmonized and temporally standardized fossil pollen dataset with a 500-year resolution from the eastern part of continental Asia. Logistic regression was used to estimate pollen abundance thresholds for vegetation occurrence (presence or dominance), based on modern pollen data and present ranges of 14 taxa in China. Our investigation reveals marked changes in spatial and temporal distributions of the major arboreal taxa. The thermophilous (Castanea, Castanopsis, Cyclobalanopsis, Fagus, Pterocarya) and eurythermal (Juglans, Quercus, Tilia, Ulmus) broadleaved tree taxa were restricted to the current tropical or subtropical areas of China during the Last Glacial Maximum (LGM) and spread northward since c. 14.5kyr BP. Betula and conifer taxa (Abies, Picea, Pinus), in contrast, retained a wider distribution during the LGM and showed no distinct expansion direction during the Late Glacial. Since the late mid-Holocene, the abundance but not the spatial extent of most trees decreased. The changes in spatial and temporal distributions for the 14 taxa are a reflection of climate changes, in particular monsoonal moisture, and, in the late Holocene, human impact. The post-LGM expansion patterns in eastern continental China seem to be different from those reported for Europe and North America, for example, the westward spread for eurythermal broadleaved taxa. KW - China KW - Holocene KW - Last Glacial Maximum KW - pollen mapping KW - vegetation expansion Y1 - 2015 U6 - https://doi.org/10.1177/0959683614556385 SN - 0959-6836 SN - 1477-0911 VL - 25 IS - 1 SP - 79 EP - 91 PB - Sage Publ. CY - London ER - TY - JOUR A1 - Herzschuh, Ulrike A1 - Pestryakova, Luidmila Agafyevna A1 - Savelieva, Larissa A. A1 - Heinecke, Liv A1 - Böhmer, Thomas A1 - Biskaborn, Boris K. A1 - Andreev, Andrei A1 - Ramisch, Arne A1 - Shinneman, Avery L. C. A1 - Birks, H. John B. T1 - Siberian larch forests and the ion content of thaw lakes form a geochemically functional entity JF - Nature Communications N2 - Siberian larch forests growing on shallow permafrost soils have not, until now, been considered to be controlling the abiotic and biotic characteristics of the vast number of thaw-lake ecosystems. Here we show, using four independent data sets (a modern data set from 201 lakes from the tundra to taiga, and three lake-core records), that lake-water geochemistry in Yakutia is highly correlated with vegetation. Alkalinity increases with catchment forest density. We postulate that in this arid area, higher evapotranspiration in larch forests compared with that in the tundra vegetation leads to local salt accumulation in soils. Solutes are transported to nearby thaw lakes during rain events and snow melt, but are not fully transported into rivers, because there is no continuous groundwater flow within permafrost soils. This implies that potentially large shifts in the chemical characteristics of aquatic ecosystems to known warming are absent because of the slow response of catchment forests to climate change. Y1 - 2013 U6 - https://doi.org/10.1038/ncomms3408 SN - 2041-1723 VL - 4 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Li, Chenzhi A1 - Postl, Alexander K. A1 - Böhmer, Thomas A1 - Cao, Xianyong A1 - Dolman, Andrew M. A1 - Herzschuh, Ulrike T1 - Harmonized chronologies of a global late Quaternary pollen dataset (LegacyAge 1.0) JF - Earth system science data : ESSD N2 - We present a chronology framework named LegacyAge 1.0 containing harmonized chronologies for 2831 pollen records (downloaded from the Neotoma Paleoecology Database and the supplementary Asian datasets) together with their age control points and metadata in machine-readable data formats. All chronologies use the Bayesian framework implemented in Bacon version 2.5.3. Optimal parameter settings of priors (accumulation.shape, memory.strength, memory.mean, accumulation.rate, and thickness) were identified based on information in the original publication or iteratively after preliminary model inspection. The most common control points for the chronologies are radiocarbon dates (86.1 %), calibrated by the latest calibration curves (IntCal20 and SHCal20 for the terrestrial radiocarbon dates in the Northern Hemisphere and Southern Hemisphere and Marine20 for marine materials). The original publications were consulted when dealing with outliers and inconsistencies. Several major challenges when setting up the chronologies included the waterline issue (18.8% of records), reservoir effect (4.9 %), and sediment deposition discontinuity (4.4 %). Finally, we numerically compare the LegacyAge 1.0 chronologies to those published in the original publications and show that the reliability of the chronologies of 95.4% of records could be improved according to our assessment. Our chronology framework and revised chronologies provide the opportunity to make use of the ages and age uncertainties in synthesis studies of, for example, pollen-based vegetation and climate change. The LegacyAge 1.0 dataset, including metadata, datings, harmonized chronologies, and R code used, is openaccess and available at PANGAEA (https://doi.org/10.1594/PANGAEA.933132; Li et al., 2021) and Zenodo (https://doi.org/10.5281/zenodo.5815192; Li et al., 2022), respectively. Y1 - 2022 U6 - https://doi.org/10.5194/essd-14-1331-2022 SN - 1866-3508 SN - 1866-3516 VL - 14 IS - 3 SP - 1331 EP - 1343 PB - Copernics Publications CY - Katlenburg-Lindau ER -