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›› 2017, Vol. 34 ›› Issue (6): 719-733.DOI: 10.7523/j.issn.2095-6134.2017.06.009

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Modern pollen-vegetation relationships and two new pollen-climate indices in the Yarlung Zangbo River basin in southern Tibetan Plateau

SUN Aizhi1, ZHANG Dehuai2, DAI Ranran2   

  1. 1. Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences, College of Earth Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    2. School of Geographical Sciences, Southwest University, Chongqing 400715, China
  • Received:2016-06-22 Revised:2017-05-25 Online:2017-11-15
  • Supported by:
    Supported by the National Natural Science Foundation of China (41172332, 41002058) and Open research fund of Key laboratory of Tibetan Environmental Changes and Land Surface Processes of Chinese Academy of Sciences

Abstract: This study collected 70 pollen surface samples along an east-west transection in the Yarlung Zangbo River (YLZR) basin in the southern Tibetan Plateau. Pollen assemblage and principle components analysis results show that each vegetation zone along the transection is characterized by distinctive modern pollen assemblages as follows:1) pine forest zone:Pinus pollen assemblage; 2) fir and spruce forest zone:Abies-Pinus-Picea pollen assemblage; 3) broadleaved forest/shrubland zone:Quercus-Betula-Pinus pollen assemblage; 4) alpine meadow zone:Cyperaceae-Artemisia-Compositae pollen assemblage; and 5) alpine steppe zone:Artemisia-Cyperaceae-Poaceae pollen assemblage. We use the data to define two new pollen-climate indices, (Pi, Ti), based on the ratio between major pollen taxon groups and subgroups. The indices represent the mean annual precipitation (MAP) and mean annual temperature (MAT) of the study area, and they closely track the regional west-east gradients in precipitation and temperature across the YLZR basin. We suggest that the pollen-vegetation-climate indices may be useful for future palaeoclimatic reconstructions using fossil pollen data.

Key words: modern pollen assemblages, PCA, climate gradient, pollen-climate indices, the Yarlung Zangbo River basin

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