Boreal forest bi-stability around Lake El’gygytgyn (NE Russia) during interglacial of the last 2.15 Million years

过去 215 万年间冰期期间 Elâgygytgyn 湖（俄罗斯东北部）周围的北方森林双稳定性

• 批准号: 398626025
• 负责人: Professorin Dr. Ulrike Herzschuh
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398626025?language=en
• 关键词: Boreal; forest; bi; stability; around

Ecosystem services of boreal forests are of critical importance for humanity and differ markedly between evergreen and summergreen needle-leaf forests. The proposed project will address the timely questions “Why is northern Asia dominated by larch forests during the Holocene while it was covered by evergreen needle-leaf forests during previous interglacials of seemingly similar climate conditions?"Our overall hypothesis is that summergreen and evergreen needle-leaf forests represent alternative quasi-stable states that can occur under similar climate conditions during interglacials of the last 2 Myr, being triggered by different environmental conditions and the composition of northern tree refugia during the preceding glacials.We will address this hypothesis by a multiproxy investigation of Lake El'gygytgyn sediments (Chukotka, NE Asia) that were collected as part of the ICDP programme.Investigations in Work Package 1 (group M. Melles) aim to track regional vegetation change of the last 2 Myrs using pollen data which includes new analyses of ~500 pollen samples as well as its integration with available data.The sedimentary ancient DNA analyses to be performed in Work package 2 (group U. Herzschuh) will aid the interpretability of pollen data. In particular, the regional vegetation signal of pollen will be verified, the composition of the regional tree refugia and the species-specific taxa composition will be revealed to allow the separation tree vs. shrub growth forms of certain woody genera. In Work Package 3 (group H. Meyer), regional climate change of selected glacial/interglacial cycles of the last 2.15 Myrs will be reconstructed from stable oxygen isotope analyses of diatom valves. Gained results will be used to assess globally available high-resolution paleoclimate records for its suitability to represent NE Asian climate change at glacial/interglacial time-scale.Gained results will be compiled and re-analysed to assess the stated hypothesis jointly by all working group members in Work Package 4 (synthesis).

北方针叶林的生态系统服务功能对人类至关重要，万年青针叶林和夏绿针叶林的生态系统服务功能存在显著差异。拟议的项目将解决以下及时的问题：“为什么北方亚洲在全新世以落叶松林为主，而在以前气候条件似乎相似的间冰期却被万年青针叶林覆盖？“我们的总体假设是，夏绿和万年青针叶林代表了过去200万年间冰期期间在类似气候条件下可能发生的替代准稳定状态，这是由不同的环境条件和前冰期期间北方树木避难所的组成触发的。我们将通过对El'gygytgyn湖沉积物的多代理调查来解决这一假设。（Chukotka，NE Asia），作为ICDP计划的一部分收集。Melles）的目标是利用花粉数据追踪最近200万年的区域植被变化，其中包括对约500个花粉样本的新分析以及与现有数据的整合。Herzschuh）将有助于花粉数据的解释。特别是，花粉的区域植被信号将得到验证，区域树木避难所的组成和物种特异性分类组成将被揭示，以允许某些木本属的树木与灌木生长形式的分离。在工作包3（H组）中，Meyer），区域气候变化的选择冰川/间冰期循环的最后2.15万年将重建稳定的氧同位素分析硅藻阀。所获得的结果将用于评估全球可用的高分辨率古气候记录，以确定其是否适合代表东北亚地区在冰期/间冰期时间尺度上的气候变化。所获得的结果将被汇编和重新分析，以评估工作包4（综合）中所有工作组成员共同提出的假设。