末次间冰期以来欧亚黄土区植被及气候变化研究

Abstract: Climate change caused by greenhouse gases such as CO2 released by human activities has already had a significant impact on the global vegetation, and has triggered a series of disastrous events such as the extinction of plant species, the reductions of plant diversity and crops. In order to evaluate the impact of the global climate change on vegetation in different climatic provinces of Eurasian loess belt, this research program intends to select 3 loess sections on the Chinese Loess Plateau and the Russian plain. Through, systematically studies of chronology, sedimentology and palynology from the loess-paleosol sequences, we aim to 1) establish the history of vegetation and plant diversity changes since the last interglacial, 2) to quantitatively and semi-quantitatively reconstruct the variations of temperature and precipitation since the last interglacial on the Chinese Loess Plateau and the Russian Plains. 3) Comparing the vegetation and climatic records of the Loess Plateau and the Russian Plains from the last interglacial to the Holocene, and to explore the response of vegetation to climate change in different climatic zones and 4) to provide a scientific basis for policy makers to deal with issues associated with future global climate change.

摘要：人类活动排放大量CO2等温室气体造成的气候变化已经对全球植被产生了显著影响，并引发了植物物种灭绝、植物多样性降低、农作物减产等一系列灾害事件。据估计，本世纪全球平均温度仍会持续上升，因此，科学评估气候变化对植被的影响成为紧迫知识需求。本项目拟在位于东亚季风边缘区的黄土高原以及位于北半球西风带的俄罗斯平原各选取1个和2个黄土剖面，通过对两地黄土-古土壤序列进行系统的年代学、沉积学以及孢粉学等研究，重建末次间冰期以来黄土高原和俄罗斯平原植被及植物多样性变化历史，并基于孢粉记录尝试定量-半定量重建黄土区温度及降水。通过对比末次间冰期至全新世气候变化过程中黄土高原以及俄罗斯平原的植被记录，探讨不同气候区植被对气候变化的响应机制及差异，为应对未来全球气候变化提供科学依据。

为了解全球增温背景下欧亚黄土带不同气候区内植被的响应状况，本项目在位于东亚季风边缘区的黄土高原选取了景泰黄土剖面以及在位于北半球西风带的东欧平原上选取了Strelitsa、Beglitsa两个黄土剖面，通过对东亚季风区以及北半球西风区三个黄土‒古土壤序列进行系统的粒度与磁化率分析、年代学以及孢粉学研究，重建了MIS7以来东欧平原和黄土高原植被及植物多样性变化历史，定量‒半定量重建了三地古温度及降水状况。通过对比MIS7至全新世气候变化过程中东欧平原以及黄土高原的植被记录，探讨不同气候区植被对气候变化的响应机制及差异，获得了以下认识：.（1）欧亚黄土干旱‒半干旱气候区内，木本植物大量生长于凉湿的间冰阶，植物多样性较高；间冰期及冰期气候较干，多发育草原及森林草原植被，植物多样性低。.（2）黄土高原景泰地区间冰阶呈现出两种植被景观，厚层黄土堆积区发育荒漠草原，基岩山区及河谷区生长有以云杉为主的针叶林。.（3）东欧平原在冰期‒间冰期旋回过程中，冰盖变化驱动西风带位置南北移动，导致雨带迁移，使得研究区呈现间冰阶气候凉湿，冰期及间冰期气候较干的特征。