Ancient Subalpine Clonal Spruces (Picea abies) : Sources of Postglacial Vegetation History in the Swedish Scandes
Ancient Subalpine Clonal Spruces (Picea abies) : Sources of Postglacial Vegetation History in the Swedish Scandes
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古代亚高山克隆云杉（云杉）：瑞典斯坎德冰川后植被历史的来源
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发表时间：
2011
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通讯作者：
L. Kullman
中科院分区：
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作者：
Lisa Öberg;L. Kullman
这项研究解决了冰期后云杉（挪威云杉）迁移到斯堪的纳维亚半岛这一长期存在的问题。主要方法重点是利用从瑞典斯坎德斯林线生态交错带取回的云杉和其他物种的巨型化石树遗骸（木材和球果）作为植被重建的工具。核心数据来自对云杉克隆群下方土壤中保存的巨型化石进行的放射性碳测年，这些化石是由树枝生根形成的，随着时间的推移，会产生新的直立茎。在高海拔地区，我们发现了活的云杉克隆，在某些情况下，它们可能是可追溯到全新世早期（距今 9500 年）的连续克隆系列的一部分。云杉在早期阶段在瑞典斯坎德群岛的存在与之前的巨型化石推论一致。这个日期表明云杉的到来是在区域冰消之后不久，比根据花粉数据推断的到达日期早了几千年。从全新世早期的热最适期到目前，一些云杉个体的持续存在表明，即使在林线总体上比现在高得多的时期，高山景观中也存在永久开放或半开放的斑点。最初，云杉克隆似乎存在于广泛分布的松树（Pinus sylvestris）、山桦（Betula pubescens ssp. czerepanovii）、西伯利亚落叶松（Larix sibirica）和嗜热阔叶落叶树种的区域性非类似植被基质中。为了应对随后的新冰川冷却，由于松树线的降低以及落叶松和嗜热植物的消失，景观的高山特征得到了增强。云杉能够躲过火灾和其他灾难，是由于其固有的表型可塑性。整个全新世日益严峻的气候使它们成为残废的克鲁姆霍尔兹，几乎完全被积雪覆盖，从而免受冬季压力。冰消后不久，云杉专门出现在斯堪的纳维亚半岛西部，这可能表明该物种从“神秘的”冰河时代避难所迁徙到斯堪的纳维亚半岛，比传统认为的更近。
This study addresses the long-standing issue of postglacial immigration of Picea abies (Norway spruce) into Scandinavia. The main methodological focus is on using megafossil tree remains (wood and cones) of spruce and other species retrieved from the treeline ecotone of the Swedish Scandes as a tool for vegetation reconstruction. The core data come from radiocarbon dating of megafossils preserved in the soil underneath clonal groups of Picea abies , formed by rooting of branches that over time give rise to new upright stems. At high elevations, we found living spruce clones, which in some cases may be part of a continuous clonal series dating back to the early Holocene (9500 cal. yr BP). The presence of Picea in the Swedish Scandes at this early stage concurs with previous megafossil inferences. This date, which places the arrival of Picea very soon after regional deglaciation, is several millennia earlier than the arrival date inferred from pollen data. The persistence of some individual Picea clones from the early Holocene thermal optimum to the present implies that permanently open or semi-open spots existed in the high-mountain landscape even during periods when treelines in general were much higher than at present. Initially, Picea clones appear to have existed in a regional no-analogue vegetation matrix of widely scattered pine ( Pinus sylvestris ), mountain birch ( Betula pubescens ssp. czerepanovii ), Siberian larch ( Larix sibirica ) and thermophilic broadleaved deciduous species. In response to subsequent neoglacial cooling, the alpine character of the landscape has been enhanced through a lowered pine treeline and the disappearance of larch and thermophiles. The endurance of spruces, which escaped fire and other calamities, is due to their inherent phenotypic plasticity. Increasing climatic harshness throughout the Holocene conserved them as crippled krummholz, protected from winter stress by almost complete snow coverage. The appearance of Picea abies exclusively in western Scandinavia shortly after the deglaciation could suggest that the species immigrated from “cryptic” ice age refugia much closer to Scandinavia than conventionally thought.