Knowledge Resource Center for Ecological Environment in Arid Area
| 青藏高原东部更新世中期植被多样性演化与机制 | |
| 其他题名 | Floristic Diversity and its Dynamics in the Eastern Tibetan Plateau during the Mid-Pleistocene |
| 刘耀亮 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 赵艳 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 生物多样性的形成及演变机制是21世纪急需解决的重大科学问题之一，也是进行生物多样性保护的基础。青藏高原发育有高寒地区独特的生态系统和生物多样性，丰富的物种资源和对气候变化的敏感性，使其成为全球生物多样性研究的热点地区。在全球变暖的气候背景下，青藏高原高寒生态系统及其生物多样性十分脆弱。对青藏高原古植被多样性的演化过程和机制研究，可为该地区今后生物多样性变化预测提供理论依据，为青藏高原生态保护和生态安全建设提供参考。若尔盖盆地位于青藏高原东部边缘，是森林、草甸和草原等不同植被类型的交界地带。该区植被对气候变化十分敏感，同时还沉积有第四纪湖相沉积物，是开展长序列古植被多样性研究的理想区域。本研究以若尔盖古湖中心的ZB13-C2钻孔（33°58.163′N，102°19.855′E，海拔3434 m）沉积物为研究对象，利用高分辨率（约1.2 ka/样品）的孢粉记录，结合主成分分析、生物群区化和孢粉多样性等方法，重建了研究区更新世中期（1000-640 ka）时期的古植被变化过程以及植被多样性演化历史，并探讨了该区域植被多样性演化的驱动机制。主要结论如下：（1）若尔盖ZB13-C2钻孔更新世中期（1000-640 ka）时期的孢粉组合特征和生物群区化植被重建结果显示，若尔盖盆地及周边地区的植被景观以高山草原和高山草甸为主，以云杉为主的森林景观与之交替出现；灌丛景观和荒漠景观很少出现。（2）若尔盖ZB13-C2钻孔孢粉多样性揭示的植被多样性变幅和变频较大，其演化过程可以分为3个阶段：早期（1000-791 ka）植被均匀度在波动中升高，且高值出现的频次也较高，物种丰富度在波动中先下降后升；中期（791-697 ka）植被均匀度相对较低而物种丰富度相对较高，二者的变化幅度相对较低；晚期（697-640 ka）植被均匀度变化幅度略有升高，物种丰富度则在波动中缓慢升高。（3）若尔盖地区的植被多样性在间冰期与冰期尺度上的变化最为明显。间冰期时，植被的物种丰富度降低而均匀度上升，冰期时则相反。将植被演替过程、植物多样性变化历史与全球温度记录进一步对比分析后发现，温度变化驱动若尔盖盆地植物群落组成和植被类型发生改变，进而触发植被多样性的变化。 |
| 英文摘要 | Tibetan Plateau (TP) has become a research hotspot for global biodiversity studies due to its unique alpine ecosystems, rich natural resources and sensitivities to the climate changes. With global warming, the alpine ecosystems on TP is under the pressure of the rapid decline in biodiversity. Our study on the past floristic diversity and its dynamics will provide effective theory basis for predicting multi scenarios of biodiversity changes on TP in the future, and provide practical references for ecological protection and environmental safety of construction on TP.Zogie Basin is located at the east margin of TP within the shared-border of forest, meadow and steppe. The high sensitivity of vegetation to climate changes and the availability of the continues Quaternary lacustrine sedimentation make Zogie Basin become the ideal region for the investigation on floristic diversity at a long-time scale. A high resolution pollen record (ca.1.2 ka per sample) obtained at site ZB13-C2 (33°58.163′N，102°19.855′E，3434 m a.s.l.) from the center of paleolake. Principal component analysis (PCA), biomisation analysis and pollen diversity index were employed to reconstruct vegetation history and floristic diversity for the past 1000-640 ka, furthermore to discuss the dynamics of the changes of floristic diversity in the study area. The major results are as following: (1) The pollen record and biomization result at studied site ZB13-C2 indicate that during Middle Pleistocene（1000-640 ka）, the dominated vegetation in Zogie Basin and its surrounding were characterized by the alternative occurrence of spruce forest, and the alpine steppe and /or meadow while less occurrence of shrubs and desert. (2) The history of floristic diversity of ZB13-C2 in Zogie Basin based on pollen record suggests three stages during the Middle Pleistocene: ① during the earlier period (1000-791 ka), the species evenness shows increased volatility with more occurrences of the high values, the species richness decreased firstly then rose with fluctuations; ② during the middle period (791-697 ka), the evenness of species was relatively low and the species richness was relatively high, while the variations of the both remained relatively stable; ③ during the late period (697-640 ka), the amplitude varies of the species evenness rose again, while the species richness rose with fluctuations.(3) The changes of floristic diversity of ZB13-C2 in Zogie Basin were obvious over the glacial-interglacial cycles during the Middle Pleistocene. The species evenness rose as the richness decreased during the interglacial periods, while during the glacial periods the situation is on the contrary, i.e. the species evenness decreased as the richness increased. The comparisons between vegetation succession processes, the changes history of floristic diversity and the record of global average surface temperature suggest the temperature was the key driver of the changes of vegetation types and the vegetation composition in Zogie Basin, which triggered the changes of floristic diversity. |
| 中文关键词 | 孢粉 ; 植被多样性 ; 更新世中期 ; 若尔盖 ; 青藏高原 |
| 英文关键词 | Pollen Floristic diversity Middle Pleistocene Zogie Basin Tibetan Plateau (TP) |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院地理科学与资源研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288079 |
| 推荐引用方式 GB/T 7714 | 刘耀亮. 青藏高原东部更新世中期植被多样性演化与机制[D]. 中国科学院大学,2018. |
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