文章基本信息

标题：Dynamics at the treeline: differential responses of Picea mariana and Larix laricina to climate change in eastern subarctic Québec
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作者：Geneviève Dufour-Tremblay ; Esther Lévesque ; Stéphane Boudreau 等
期刊名称：Environmental Research Letters
印刷版ISSN：1748-9326
电子版ISSN：1748-9326
出版年度：2012
卷号：7
期号：4
页码：044038
DOI：10.1088/1748-9326/7/4/044038
语种：English
出版社：IOP Publishing Ltd
摘要：Treelines are known to be temperature-sensitive ecotones, and therefore could rapidly expand their range limits in response to climate warming. Observations of lack of range expansion, however, indicate that ecological constraints partly control the treeline ecotones. The main objectives of this study were to evaluate Picea mariana and Larix laricina recruitment and growth at and above the altitudinal treeline of Kangiqsualujjuaq (Nunavik), where warmer temperatures since the 1990s have already triggered shrub expansion. We mapped, harvested, dated and measured tree individuals along two altitudinal gradients from the forested stands below the treeline to hilltops. Since the 1990s, a pulse of L. laricina seedling establishment has occurred at and above the treeline. Dendrochronological analysis revealed that L. laricina underwent a rapid vertical growth and radial growth that accelerated from the 1990s. No recruitment was observed for P. mariana in response to the regional warming, suggesting a regeneration failure of this species. Our results indicated that the L. laricina colonization below and above the treeline in recent decades in response to the regional warming should modify the landscape physiognomy of the study area in the near future.