| 题名 | 中全新世以来九寨沟地区的孢粉组合与植被、气候演化 |
| 作者 | 李静静 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009-05-01 |
| 导师 | 高信芬 |
| 关键词 | 孢粉 九寨沟芦苇海 植被 古气候古环境演化 中全新世 pollen analysis Jiuzhaigou Paleovegetation Paleoenvioronment mid-Holocene |
| 其他题名 | The Evolution of Vegetation and Climate Based on the Sporo-pollen Assemblages since Mid-Holocene in Jiuzhaigou |
| 中文摘要 | 青藏高原由于其特殊的地理位置和地形地貌，不仅对邻近地区的气候环境产生重要影响，而且对东亚乃至全球大气环流的形成也产生着巨大影响，长期以来成为气候和环境变化研究的热点区域。我国不少学者对青藏高原或其边缘地区全新世以来的气候变化进行了研究，并取得了丰富的研究成果。但从研究区域来看，已有的孢粉分析工作多集中在高海拔高寒草原、灌丛草甸－荒漠地区，揭示了草原－森林植被变化的过程与环境变化的特点,青藏高原边缘森林区全新世的植被气候变化缺少详细的孢粉记录，仅于四川西部冕宁县杀野马湖、彝海、西昌地区的大海子、红海等地区有少量报道。九寨沟位于青藏高原东北部，属亚高山寒温性针叶林分布区，分布有众多的湖泊，受人类影响十分微弱，是研究全新世古气候、古环境演化的理想地点。尤其是中全新世以来与人类文明形成最为密切的一时期的环境变化，直接关系到该地区现今人类的生存和未来的发展。 本文在九寨沟保护区野外考察的基础上选取连续剖面，利用14C测年及孢粉分析方法对1.2 m的沉积剖面进行了系统的孢粉学研究。重建了中全新世以来九寨沟地区的植被和气候变化历史，初步探讨了九寨沟区域中全新世以来全球气候变化的植被响应和区域气候特点及其可能气候的驱动机制。通过研究获得的主要认识有： （1）据不同植物花粉类型在该剖面上的变化特征，由下而上可划分为4个孢粉组合带。 （2）依据孢粉组合的分带特征，对九寨沟地区中全新世以来的古植被与古气候进行了恢复，得到4个阶段古植被的演替过程与古气候的变化过程：孢粉带Ⅰ（120-77 cm，约6210 Cal a BP-2942 Cal a BP）：植被为针叶、落叶阔叶混交林，反映了温暖偏湿的气候；孢粉带Ⅱ（77-48 cm,约2942 Cal a BP-752 Cal a BP）：植被为以针叶为主的针阔叶混交林，阔叶树种的成分较前一阶段有明显减少，气候凉偏干；孢粉带Ⅲ（48-27 cm,约752 Cal a BP-318 Cal a BP）：本阶段木本植物减少明显，草本植物增加，阔叶树的数量回升，反映气候温和稍湿；孢粉带Ⅳ（27-0 cm，约318 Cal a BP至今）：植被为以落叶阔叶树稍多的针、阔叶混交林，该时段草本植物含量达到剖面的最大值，伴人植物花粉的种类和数量也增加，受到较强人类干扰的影响。 （3）通过对研究区古气候分析，首次提出2942 Cal a BP左右是九寨沟地区大暖期结束的时间，与青藏高原其它地区前人研究结果进行对比，反映了全球气候变化的区域差异。 （4）地处青藏高原东北边缘的九寨沟芦苇海剖面6210 Cal a BP以来古植被演替历史所记录的古环境、古气候变迁过程，其总体趋势具有全球一致性。 Because of its unique geographical location and topography, Qinghai-Tibet Plateau has not only an important impact on the climate and environment of the neighboring regions, but also on the atmospheric circulation's formation of East Asia and even the whole world. It’s a hotspot area to study the climate and the environment variation. Many scholars have studied the Holocene climatic change about Qinghai-Tibet Plateau, and have obtained a lot of results. Most of these spore-pollen records are located in high-altitude alpine grassland, shrub meadow – desert area, while there are few records about the Holocene climatic change in the edge of the Qinghai-Tibet Plateau of the forest zone. A few of existed reports were limited to the Shayema Lake of western Sichuan, Yi Lake, Big Lake of Xichang, Red sea and other regions. Located in the northeast Qinghai-Tibet Plateau, Jiuzhaigou national nature reserve belongs to the sub-alpine cold temperate coniferous forests distribution area, having a large number of lakes. It is less affected by human beings and is a perfect region of studying the paleoenvironment changes of Holocene, especially the Mid-Holocene, which is closed to the form of human civilization and is correlated with the survivorship of human nowadays and the development in the future directly. On the basis of field investigation, We get 1.2m continuous section in Jiuzhaigou to systematically study the evolutionary history of paleovegetation and paleoenvironment with the help of 14C ages. The results and conclusions obtained are as follows: First, Four spore-pollen assemblages have been distinguished in ascendant order on the basis of changes of various spores and pollens. Second, The evolution of the paleovegetation and paleoclimate: ZoneⅠ: from 120cm to 77 cm (about 6210 Cal a BP-2942 Cal a BP), mixed forest of conifers and deciduous broad-leave trees reflecting the warm and wet climate; ZoneⅡ: from 77cm to 48cm (about 2942 Cal a BP-752 Cal a BP), percentage of deciduous broad-leave trees is lower than that of previous period; conifers increase obviously, reflecting a cool and dry climate; Zone Ⅲ: from 48cm to 27cm (about 752 Cal a BP-318 Cal a BP), herbs increase obviously, wooden trees are less than that of previous period, indicating a temperate and slightly wet climate; Zone Ⅳ（depth and age）: forest of deciduous broad-leave trees with Pinus, Abies. In this period, the number of herbs is the most in the whole section, and the percentage of pollens that attended by human increase, the influence of human is stronger than any before. The climatic evolution since the Mid-Holocene at Jiuzhaigou reflected by sporopollen records may be well related with the global climate change. But in ZoneⅣ, because of the influence of human, the sporopollen assemblage is not well correlated with the climate. Third, by the analysis of paleoclimate in Jiuzhaigou, indicating that 2942 Cal a BP is the time which the Hypsithermal ends in the studied region for the frist time. Compared to other previous results in Qinghai-Tibet Plateau, this work shows the regional differences of global climate change. Fourth, the general trends of the evolution of paleoenvironment and paleoclimate recorded by pollen assemblage since 6210 Cal a BP in Jiuzhaigou located in the northeast edge of Qinghai-Tibet Plateau is coincident with the globals’. |
| 语种 | 中文 |
| 学科主题 | 生态学 |
| 公开日期 | 2010-11-24 |
| 页码 | 75 |
| 内容类型 | 学位论文 |
| 源URL | [http://210.75.237.14/handle/351003/240]  |
| 专题 | 成都生物研究所_生态研究 |
| 推荐引用方式 GB/T 7714 | 李静静. 中全新世以来九寨沟地区的孢粉组合与植被、气候演化[D]. 2009. |
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