Early-Holocene afforestation processes in the lower subalpine belt of the Central Swiss Alps as inferred from macrofossil and pollen records
Early-Holocene afforestation processes in the lower subalpine belt of the Central Swiss Alps as inferred from macrofossil and pollen records
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根据大化石和花粉记录推断瑞士中部阿尔卑斯山下亚高山带的全新世早期造林过程
DOI：
10.1191/0959683605hl843rp
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
B. Ammann
中科院分区：
文献类型：
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作者：
E. Gobet;W. Tinner;C. Bigler;P. Hochuli;B. Ammann
为了重建上恩嘎丁的植被历史，我们对 Lej da Champfer 和 Lej da San Murezzan（上恩嘎丁山谷，海拔约 1800 米，瑞士东南部）过去 11800 年的连续沉积物岩心进行了花粉和植物化石分析。岩心的年表分别基于 16 和 22 放射性碳测年法。两个湖泊的全新世古植物学记录一致，但在 11 100 至 10 500 年期间，这些地点之间存在显着差异。 BP，当时 Lej da Champfer 受到再沉积过程的影响。宏观化石数据表明，全新世造林开始于大约11400cal。血压。气候恶化，即前北方涛动，停止了树木的生长，并随后推迟了树木的生长，直到大约公元 100 年。 11000 卡路里BP，当时首先是桦木，然后是樟子松，然后是300年后的落叶松，最后是西伯利亚松在湖流域内扩张。林线位于 c。新仙女木期（12 542- 11 550 cal. BP）期间，位于中部阿尔卑斯山，海拔 1500 米。我们的结果以及来自阿尔卑斯山的其他大型化石研究表明，在海拔 1500 米至 2340 米之间，几乎同时进行了造林活动（例如，亚高山下部带的樟子松）。温度约为 11 400 至 11 300 cal。血压。我们认为，森林限制物种（例如，松树、落叶松）在今天的林线（海拔高度约 2350 m）处的扩张速度可能比海拔低 550 m 时更快。早期在高海拔地区的扩张可能是由于与低海拔树木（例如樟子松）和草本植物的竞争减少所致。与氧同位素、残留 A14C、冰川波动和高山气候冷却阶段等其他指标的比较表明，全新世早期植被对气候敏感。
To reconstruct the vegetation history of the Upper Engadine, continuous sediment cores covering the past 11 800 years from Lej da Champfer and Lej da San Murezzan (Upper Engadine Valley, c. 1800 m a.s.l., southeastern Switzerland) have been analysed for pollen and plant macrofossils. The chronologies of the cores are based on 16 and 22 radiocarbon dates, respectively. The palaeobotanical records of both lakes are in agreement for the Holocene, but remarkable differences exist between the sites during the period 11 100 to 10 500 cal. BP, when Lej da Champfer was affected by re-sedimentation processes. Macrofossil data suggest that Holocene afforestation began at around 11400 cal. BP. A climatic deterioration, the Preboreal Oscillation, stopped and subsequently delayed the establishment of trees until c. 11000 cal. BP, when first Betula, then Pinus sylvestrislmugo, then Larix 300 years later, and finally Pinus cembra expanded within the lake catchment. Treeline was at c. 1500 m during the Younger Dryas (12 542- 11 550 cal. BP) in the Central Alps. Our results, along with other macrofossil studies from the Alps, suggest a nearly simultaneous afforestation (e.g., by Pinus sylvestris in the lower subalpine belt) between 1500 and 2340 m a.s.l. at around 11 400 to 11 300 cal. BP. We suggest that forest-limit species (e.g., Pinus cembra, Larix decidua) could expand faster at today's treeline (c. 2350 m a.s.l.), than 550 m lower. Earlier expansions at higher altitudes probably resulted from reduced competition with low-altitude trees (e.g. Pinus sylvestris) and herbaceous species. Comparison with other proxies such as oxygen isotopes, residual A14C, glacier fluctuations, and alpine climatic cooling phases suggests climatic sensitivity of vegetation during the early Holocene.