This dataset is the biome change data of the Tibetan Plateau since the last glacial maximum which was reconstructed by using a new method. Firstly, a random forest algorithm was applied to establish a pollen-biome classification model for reconstructing past vegetation changes of the Tibetan Plateau, and 1802 modern pollen assemblages from 17 vegetation zones in and around the Tibetan Plateau were used as the training set for the model development. The random forest model showed a reliable performance (accuracy > 76%) in predicting modern biomes from modern pollen assemblages based on a comparison with the observed biomes. Moreover, the random forest model had a significantly higher accuracy than the traditional biomization method. Then, the newly established random forest model is applied to the paleovegetation reconstruction of 51 fossil pollen sequences of the Tibetan Plateau. New age-depth models were developed for these fossil pollen records using the Bayesian method, and all fossil pollen records were linearly interpolated to 500-year time slices. Finally, the spatiotemporal changes of biomes on the Tibetan plateau over the past 22,000 years at an interval of 500 years were reconstructed by using the random forest model. This dataset can provide evidence for understanding the past variation of alpine vegetation and its mechanism; provide the basis for studying the impact of past climate change on vegetation on the Tibetan Plateau; and provide boundary conditions for climate simulation.
QIN Feng , ZHAO Yan, CAO Xianyong
This dataset is derived from the paper: Tang, H. et al. (2020). Early Oligocene vegetation and climate of southwestern China inferred from palynology. Palaeogeography, Palaeoclimatology, Palaeoecology, 560, 109988. doi:10.1016/j.palaeo.2020.109988 This data is part of Supplementary data of the paper, maily contains: Supplementary table 1) Pollen percentages, which were calculated using the collected pollen samples. Supplementary table 2) Plant functional types (PFTs) for the reconstructed paleovegetation of three sites : Wenshan (Early Oligocene), Jianchuan (Early Oligocene) and Lühe (Late Eocene). Recently, in the town of Lühe, central Yunnan, SW China, a new fossil-bearing section was found and dated as early Oligocene (~33–32 Ma) according to U-Pb isotope of volcanic tuff. The fossil-bearing section totals about 18 m in thickness. Fifty-five pollen samples were collected vertically throughout this Lühe town section. For each sample, 2–2.5 g of sediment were treated with KOH (10%,) HCl (10%) and HF (39%), then sample residues were sieved through a 5 μm nylon mesh in an ultrasonic tank. Spore and pollen grains were identified using both a light microscope (LM, Leica DM1000 microscope) and a scanning electronic microscope (SEM). Single grains were picked up by a capillary tube and then transferred to a copper stub, coated with gold and observed with a Zeiss EVO LS10 SEM. At least 300 pollen grains were counted for each sample under the LM at ×400 magnification. Then the pollen percentages were calculated using the sum of total terrestrial pollen. The paleovegetation was reconstructed following the method described by Prentice et al., 1996, Prentice and Jolly, 2000 and Ni et al. (2010). The paleobiomes were reconstructed by comparing the similarity of the palaeoflora with modern plant functional types (PFTs), according to the data published by Ni et al. (2010). The similarity between the palaeoflora and modern PFTs data was explored using Euclidean distances (Prentice et al., 1996) and the Jaccard Index Coefficient (Pound and Salzmann, 2017). The Jaccard Index Coefficient in the R package “clusteval” was used here to calculate the similarity. The palaeoflora was assigned to the biome with the highest similarity scores, taking into account dominant or key taxa.
TANG He
Airborne pollen is mainly produced and disseminated during the process of plant flowering, controlled by plant phenology and climatic conditions. As an important bioindicator of plant behavior, airborne pollen can supply information about reproductive phenology, climate and atmospheric circulations. From 2011 to 2013, airborne pollen samples were collected using a volumetric Burkard pollen trap at the Qomolangma Station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS, 28.21°N, 86.56°E; 4276 m a.s.l.), on the northern slope of the Himalayas. The sampler is a volumetric air-suction device capable of continuously gathering pollen and spore particles. Air is drawn in at a speed of 10 l/min, and airborne particles are deposited on a sticky tape mounted on a drum that makes one complete rotation per week. The tape is changed weekly after a complete rotation. Then, the tape is removed and cut into seven pieces, with each piece representing one day of sampling. The pieces are mounted on slides using glycerin and safranin. Identification and counting of pollen grains were performed under an Olympus BX41 microscope at 400× magnification; all pollen grains on each slide were counted . Pollen concentration was expressed as the daily pollen grains per cubic meter of air using a constant air intake speed of 10 l/min. The pollen concentration and percentage of each pollen taxon in each year were calculated. The pollen sampling and lab process were followed the standard methods to ensure the authenticity and reliability of the data. The pollen data can provides insights into vegetation response to climate change and has significance for interpreting fossil pollen records.
LÜ Xinmiao
By archaeological investigation and excavation in Tibetan Plateau and Hexi corridor, we discovered more than 40 Neolithic and Bronze Age sites, including Zongri, Sanjiaocheng, Huoshiliang, Ganggangwa, Yigediwonan, Shaguoliang, Guandi, Maolinshan, Dongjicuona, Nuomuhong, Qugong, Liding and so on. In this dataset, there are some basic informations about these sites, such as location, longitude, latitude, altitude, material culture and so on. On this Basis, we identified animal remains, plant fossil, selected some samples for radiocarbon dating, optically stimulated luminescence dating, stable carbon, nitrogen isotopes, polle, fungal sporen and environmental proxies. This dataset provide important basic data for understanding when and how prehistoric human lived in the Tibetan Plateau during the Neolithic and Bronze Age.
YANG Xiaoyan, Lü Hongliang, LIU Xiangjun, HOU Guangliang
This dataset contains data on the lake core sporopollen spectrum and temperature/precipitation reconstruction sequence of Yamdrog Yumtso Lake in the southern Tibetan Plateau. It is used to study the environmental changes in the Yamdrog Yumtso region by 20 ka. It is obtained by the sporopollen analysis method. This data set is obtained by laboratory measurement and calculation. The samples and data are collected and identified in strict accordance with relevant operating procedures at all stages. There are three subtables in this dataset. The first two tables comprise the following analysis data of TC1 pore sporopollen samples. Field 1: Sample Number Field 2: Sample Depth Unit: cm Field 3: Sample Age Unit: aBP Field 4: Total sporopollen concentration Units: granules/gram Field 5: Total Pollen Granules Unit: Number of grains Field 6: Total number of indicative pollen Unit: Number of grains Field 7: Identification of indicative pollen number Unit: Number of grains Field 8: Sample Weight Unit: Grams Field 9: Concentration Coefficient Units: granules / gram Field 1: Sample Number Field 2: Plant species Field 3: Pollen content Unit: % The third subtable is the reconstructed temperature precipitation and has 6 fields. Field 1: Sample Code Field 2: Sample Name Field 3: Depth Unit: cm Field 4: Age Unit: aBP Field 5: Average annual temperature Unit: 0.1 °C Field 6: Annual precipitation Unit: 0.1 mm The rock core was collected from the Yamdrog Yumtso Basin in the southern part of the Tibetan Plateau. The approximate sampling location is 90°27′E，28°56′N, and the altitude there is 4425 m.
WANG Junbo, LV Houyuan
The project studying the evolution pattern and development trend of the arid environment in western China was a major research component of the project Environmental and Ecological Science for West China, which was funded by the National Natural Science Foundation of China. The leading executive of the project was Academician Zhisheng An from the Institute of Earth Environment of the Chinese Academy of Sciences. The project ran from January 2002 to December 2004. The data collected by the project include the following: 1. History and variability data for arid regions in western China: 1) Chinese Loess Plateau mass accumulation rate data (3600-0 kyr BP): Fields include age and mass accumulation rate (MAR) (txt file). 2) Chinese Loess Plateau grain size and magnetic susceptibility data (3600-0 kyr BP): Fields include age, stacked mean grain size, and stacked magnetic susceptibility (txt file). 2. Sporopollen content data of different loess strata since 12 kyr BP in the Yaozhou District of Shanxi Province (excel table): The distributions of 27 species of sporopollen (0-397 cm) from 67 different layers of loess samples are included. 3. 10Be record data (table) 10Be concentration, magnetic susceptibility and bulk density data of loess with different thicknesses (79.67- 0.09 kyr BP). 4. Simulation data on the modulation of the East Asian monsoon resulting from orbital variability driven by the uplift of the Tibetan Plateau: ah0-sum.nc nc file, hh0-sum.nc nc file, jfh0-sum.nc nc file, kdh0-sum.nc nc file, lfh0-sum.nc nc file, mask.nc nc file, phis.nc nc file.
AN Zhisheng
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