Biome reconstruction on the Tibetan Plateau since the Last Glacial Maximum using a machine learning method  

作　　者：Feng QIN Yan ZHAO Xianyong CAO 

机构地区：[1]Key Laboratory ofLand Surface Pattern and Simulation,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China [2]Alpine Paleoecology and Human Adaptation(ALPHA)Group,State Key Laboratory of Tibetan Plateau Earth System Science(LATPES),Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Earth Sciences》2022年第3期518-535,共18页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.41690113);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA20070101);the National Natural Science Foundation of China(Grant Nos.42071114,41977395,and 41671202)。

摘　　要：Historical biome changes on the Tibetan Plateau provide important information that improves our understanding of the alpine vegetation responses to climate changes.However,a comprehensively quantitative reconstruction of the historical Tibetan Plateau biomes is not possible due to the lack of quantitative methods that enable appropriate classification of alpine biomes based on proxy data such as fossil pollen records.In this study,a pollen-based biome classification model was developed by applying a random forest algorithm(a supervised machine learning method)based on modern pollen assemblages on and around the Tibetan Plateau,and its robustness was assessed by comparing its results with the predictions of the biomisation method.The results indicated that modern biome distributions reconstructed using the random forest model based on modern pollen data generally concurred with the observed zonal vegetation.The random forest model had a significantly higher accuracy than the biomisation method,indicating the former is a more suitable tool for reconstructing alpine biome changes on the Tibetan Plateau.The random forest model was then applied to reconstruct the Tibetan Plateau biome changes from 22 ka BP to the present based on 51 fossil pollen records.The reconstructed biome distribution changes on the Tibetan Plateau generally corresponded to global climate changes and Asian monsoon variations.In the Last Glacial Maximum,the Tibetan Plateau was mainly desert with subtropical forests distributed in the southeast.During the last deglaciation,the alpine steppe began expanding and gradually became zonal vegetation in the central and eastern regions.Alpine meadow occupied the eastern and southeastern areas of the Tibetan Plateau since the early Holocene,and the forest-meadow-steppe-desert pattern running southeast to northwest on the Tibetan Plateau was established afterwards.In the mid-Holocene,subtropical forests extended north,which reflected the“optimum”condition.During the late Holocene,alpine meadows and alpi

关 键 词：Biome reconstruction Random forest algorithm Biomisation method Pollen data Last Glacial Maximum Tibetan Plateau 

分 类 号：Q948.1[生物学—植物学]