气候变化领域集成服务门户(CCPortal): Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia

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DOI	10.1073/pnas.2107977118
	Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia
	Monteath A.J.; Gaglioti B.V.; Edwards M.E.; Froese D.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:52
英文摘要	The collapse of the steppe-tundra biome (mammoth steppe) at the end of the Pleistocene is used as an important example of topdown ecosystem cascades, where human hunting of keystone species led to profound changes in vegetation across high latitudes in the Northern Hemisphere. Alternatively, it is argued that this biome transformation occurred through a bottom-up process, where climate-driven expansion of shrub tundra (Betula, Salix spp.) replaced the steppe-tundra vegetation that grazing megafauna taxa relied on. In eastern Beringia, these differing hypotheses remain largely untested, in part because the precise timing and spatial pattern of Late Pleistocene shrub expansion remains poorly resolved. This uncertainty is caused by chronological ambiguity in many lake sediment records, which typically rely on radiocarbon (14C) dates from bulk sediment or aquatic macrofossils-materials that are known to overestimate the age of sediment layers. Here, we reexamine Late Pleistocene pollen records for which 14C dating of terrestrial macrofossils is available and augment these data with 14C dates from arctic ground-squirrel middens and plant macrofossils. Comparing these paleovegetation data with a database of published 14C dates from megafauna remains, we find the postglacial expansion of shrub tundra preceded the regional extinctions of horse (Equus spp.) and mammoth (Mammuthus primigenius) and began during a period when the frequency of 14C dates indicates large grazers were abundant. These results are not consistent with a model of top-down ecosystem cascades and support the hypothesis that climate-driven habitat loss preceded and contributed to turnover in mammal communities. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Eastern Beringia; Keystone species; Megafauna; Palaeoecology; Steppetundra
语种	英语
scopus关键词	animal; biodiversity; birch; climate; history; mammal; paleontology; population dynamics; species extinction; tundra; Animals; Betula; Biodiversity; Climate; Extinction, Biological; History, Ancient; Mammals; Paleontology; Population Dynamics; Tundra
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/250902
作者单位	Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AL T6G 2R3, Canada; School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Water and Environmental Research Center, University of Alaska, Fairbanks, AK 99775, United States; Alaska Quaternary Center, University of Alaska, Fairbanks, AK 99775, United States
推荐引用方式 GB/T 7714	Monteath A.J.,Gaglioti B.V.,Edwards M.E.,et al. Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia[J],2021,118(52).
APA	Monteath A.J.,Gaglioti B.V.,Edwards M.E.,&Froese D..(2021).Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia.Proceedings of the National Academy of Sciences of the United States of America,118(52).
MLA	Monteath A.J.,et al."Late Pleistocene shrub expansion preceded megafauna turnover and extinctions in eastern Beringia".Proceedings of the National Academy of Sciences of the United States of America 118.52(2021).