Paleoclimatic implications of glacial and postglacial refugia for Pinus pumila in western Beringia

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• 作者：Patricia M. Anderson ; Anatoly V. Lozhkin ; Tatiana B. Solomatkina ; Thomas A. Brown
• 关键词：Refugium ; Seasonality ; Pollen ; Northeastern Siberia ; Beringia ; Late Quaternary
• 刊名：Quaternary Research
• 出版年：2010
• 出版时间：March 2010
• 年：2010
• 卷：73
• 期：2
• 页码：269-276
• 全文大小：767 K

文摘

Palynological results from Julietta Lake currently provide the most direct evidence to support the existence of a glacial refugium for Pinus pumila in mountains of southwestern Beringia. Both percentages and accumulation rates indicate the evergreen shrub survived until at least  19,000 ¹⁴C yr BP in the Upper Kolyma region. Percentage data suggest numbers dwindled into the late glaciation, whereas pollen accumulation rates point towards a more rapid demise shortly after  19,000 ¹⁴C yr BP. Pinus pumila did not re-establish in any great numbers until  8100 ¹⁴C yr BP, despite the local presence  9800 ¹⁴C yr BP of Larix dahurica, which shares similar summer temperature requirements. The postglacial thermal maximum (in Beringia  11,000–9000 ¹⁴C yr BP) provided Pinus pumila shrubs with equally harsh albeit different conditions for survival than those present during the LGM. Regional records indicate that in this time of maximum warmth Pinus pumila likely sheltered in a second, lower-elevation refugium. Paleoclimatic models and modern ecology suggest that shifts in the nature of seasonal transitions and not only seasonal extremes have played important roles in the history of Pinus pumila over the last  21,000 ¹⁴C yr BP.