The Late Pleistocene landscape in northern Eurasia and North America was inhabited by a specific megafaunal complex, which largely disappeared during the Pleistocene/Holocene transition. Vegetation changes are considered as one of the factors responsible for these extinctions, but the structure and composition of the Pleistocene vegetation are still poorly known. Here we complement previous studies by comparing the taxonomic composition of the plant remains found in the gastrointestinal tracts of the frozen carcasses of Pleistocene megaherbivores with the species composition of the current Siberian vegetation. We compiled a dataset of palaeobotanical records from frozen individuals of Pleistocene megaherbivores found in northern Siberia and Beringia and dated to the period from more than 50 kyr BP to 9 kyr BP. We also compiled a dataset of vegetation plots from several regions in Siberia. We analysed the similarity in taxonomic composition of plants between these two datasets using a novel method that accounts for variable taxonomic resolution in palaeobotanical data. For most megaherbivore individuals, plant remains in their gastrointestinal tracts corresponded to tundra, forest and mire vegetation, while they showed low similarity to steppe. This pattern was relatively constant over time, showing no remarkable differences between the Last Glacial Maximum and the periods before and afterwards. This suggests that during the Upper Pleistocene, a mosaic of mesic and wet vegetation types such as tundra with patches of forests and mires was common in northern Siberia and Beringia. In contrast, the steppe was rare to absent in the landscape or underused by the megaherbivores as a pasture since they found enough food in the widespread mesic and wet habitats with more productive vegetation.

中文翻译：

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从冷冻动物残骸重建的更新世巨型食草动物的栖息地

欧亚大陆北部和北美的晚更新世景观居住着一种特定的巨型动物群，在更新世/全新世过渡期间大部分消失。植被变化被认为是造成这些灭绝的因素之一，但更新世植被的结构和组成仍知之甚少。在这里，我们通过比较更新世巨型食草动物冷冻尸体的胃肠道中发现的植物遗骸的分类组成与当前西伯利亚植被的物种组成来补充先前的研究。我们编制了一个古植物学记录数据集，这些记录来自在西伯利亚北部和白令岛发现的更新世巨型食草动物的冷冻个体，其历史可以追溯到 50 kyr BP 到 9 kyr BP 时期。我们还编制了一个来自西伯利亚几个地区的植被图数据集。我们使用一种新方法分析了这两个数据集之间植物分类组成的相似性，该方法解释了古植物数据中可变的分类分辨率。对于大多数大型食草动物个体而言，其胃肠道中的植物残骸对应于苔原、森林和沼泽植被，而它们与草原的相似性较低。随着时间的推移，这种模式相对稳定，末次盛冰期与前后时期之间没有显着差异。这表明，在上更新世期间，西伯利亚北部和白令海峡常见中湿植被类型的镶嵌，例如带有森林和泥沼斑块的苔原。相比之下，