Pollen R-values in arid central Asia for quantitative palaeo-vegetation reconstruction
Pollen R-values in arid central Asia for quantitative palaeo-vegetation reconstruction
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DOI：
10.1016/j.palaeo.2022.110993
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发表时间：
2022-04-14
影响因子：
3
通讯作者：
Wang，Yu-Fei
中科院分区：
文献类型：
--
作者：
Wang，Qiang;Li，Jin-Feng;Wang，Yu-Fei
建立地表孢粉组合与相关现代植被的关系，为重建古植被演替及相关气候变化提供了桥梁。大量研究表明，某些分类群表层花粉组合的相对丰度值与相应的现代植被的相对丰度值不一致，这是由于它们的花粉产生、扩散方式和保存潜力不同所致。因此，引入了R值的概念作为校正系数来抵消这一差异。与大多数复杂的森林和草原生态系统不同，优势类群较少的沙漠植被提供了一个更简单的模型来演示如何使用R值来纠正这种偏差。在这里，我们提出了一种现代沙漠植被类型的相对中值方案，该方案是基于利用表层花粉和相关的现代植被数据计算的优势类群的随机相对调整系数，这些数据来自中亚东部干旱的东西沙漠样带上的145个样地。结果表明：1)以白刺为参照物，藜科、蒿属和麻黄属具有较高的代表性，而罗望科、十字花科、菊科(不包括蒿属)、沙拐枣属和禾本科的代表性较低。2)花粉表现受授粉策略的制约。例如，风媒植物(如麻黄、蒿属和藜科)的比例大多偏高，而昆虫类(如白刺、罗望子科、枣科和沙拐枣)的比例较低。上述方案和结果为未来ACA古植被演替的定量重建提供了新的思路。
Establishing the relationship between surface pollen assemblages and related modern vegetation provides a bridge for reconstructing the palaeo-vegetation succession and related climate changes. Numerous contributions have demonstrated an inconsistency between the relative abundance values of surface pollen assemblages and corresponding modern vegetation for some taxa, which is attributed to differences in their pollen production, dispersal mode and preservation potential. Consequently, the concept of R-value was introduced as a correction coefficient to counterbalance this discrepancy. Unlike most of the complex forest and grassland ecosystems, desert vegetation with fewer dominant taxa provides a simpler model to demonstrate how to use the R-value to correct this deviation. Here, we propose a scheme ofRrelmedian values from modern desert vegetation types based on calculatedRandRreladjustment coefficients of the dominant taxa using surface pollen and related modern vegetation data from 145 sample plots along an east-west desert transect in the eastern arid central Asia (ACA). These data revealed that 1) takingNitrariaas a reference, Chenopodiaceae,ArtemisiaandEphedraare highly represented, while Tamaricaceae, Zygophyllaceae, Asteraceae (excludingArtemisia),Calligonumand Poaceae are poorly represented. 2) the pollen representation was constrained by their pollination strategies. For example, anemophilous plants (e.g.,Ephedra,Artemisiaand Chenopodiaceae) are mostly over-represented, while those of entomophilous taxa (e.g.,Nitraria, Tamaricaceae, Zygophyllaceae andCalligonum) are under-represented. The scheme and findings mentioned above cast a new light on the future of quantitative reconstruction of palaeo-vegetation succession in the ACA.