Macrofossils as records of plant responses to rapid Late Glacial climatic changes at three sites in the Swiss Alps
详细信息 查看全文
- 作者：Tobolski ; Kazimierz ; Ammann ; Brigitta
- 关键词：biotic response ; climatic change ; Late Glacial ; plant macrofossils ; Switzerland ; Younger Dryas
- 刊名：Palaeogeography, Palaeoclimatology, Palaeoecology
- 出版年：2000
- 出版时间：June 15, 2000
- 年：2000
- 卷：159
- 期：3-4
- 页码：251-259
- 全文大小：257 K
文摘
Plant macrofossils from the end of the Younger Dryas were analysed at three sites, Gerzensee (603m asl), Leysin (1230m asl), and Zeneggen (1510m asl). For the first two sites an oxygen-isotope record is also available that was used to develop a time scale (Schwander et al., this volume); dates refer therefore to calibrated years according to the GRIP time scale. Around Gerzensee a pine forest with some tree birches grew during the Younger Dryas. With the onset of the isotopic shift initiating the rapid warming (about 11,535 cal. years before 1950), the pine forest became more productive and denser. At Leysin no trees except some juniper scrub grew during the Younger Dryas. Tree birches, pine, and poplar immigrated from lower altitudes and arrived after the end of the isotopic shift (about 11,487B.P.), i.e., at the beginning of the Preboreal (at about 11,420B.P.). Zeneggen is situated somewhat higher than Leysin, but single tree birches and pines survived the Younger Dryas at the site. At the beginning of the Preboreal their productivity and population densities increased. Simultaneously shifts from Nitella to Chara and from silt to gyttja are recorded, all indicating rapidly warming conditions and higher nutrient levels of the lake water (and probably of the soils in the catchment). At Gerzensee the beginning of the Younger Dryas was also analysed: the beginning of the isotopic shift correlates within one sample (about 15 years) to rapid decreases of macrofossils of pines and tree birches.