Zhao Yan, Qin Feng, Cui Qiaoyu, Li Quan, Cui Yifan, Birks H John B, Liang Chen, Zhao Wenwei, Li Huan, Ren Weihe, Deng Chenglong, Ge Junyi, Kong Yanfen, Liu Yaoliang, Zhang Zhiyong, Zhang Jiawu, Cai Maotang, Wei Haicheng, Qiu Hongyi, Xu Haitao, Yang Hanfei, Chen Chunzhu, Piao Shilong, Guo Zhengtang
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Ecol Evol. 2025 Jun 13. doi: 10.1038/s41559-025-02743-2.
The Tibetan Plateau supports the largest alpine meadow ecosystem globally. It is considered extremely vulnerable to global warming. Knowledge of past vegetation dynamics under similarly warm climates could shed insights into where the tipping point for regime shifts may lie. We report a continuous multicentennial-resolved pollen record for the last 3.5 Myr from a lake sediment core retrieved from the Zoige Basin (~3,350-3,450 m above sea level) on the eastern Tibetan Plateau. It reveals a detailed picture of the vegetation dynamics across several timescales using the approaches of biomization, numerical analysis, statistical modelling and vegetation simulations. These lines of evidence show that vegetation underwent transformation from stable forest in the mid-late Pliocene Period (3.5-2.73 million years ago (Ma)) to codominance of forest and steppe in the early Quaternary Period (2.73-1.54 Ma) and to a meadow-dominated ecosystem after ~1.54 Ma, along with glacial-interglacial and millennial-scale grassland-forest shifts. These vegetational changes were largely controlled by temperature change. A global warming of ~2-3 °C is the most important threshold for the forest expansion and meadow resilience loss on the Tibetan Plateau. By analogy to the past, we suggest that, without major reductions in greenhouse gas emissions, the current Tibetan Plateau meadow is at risk of major transformation.
青藏高原是全球最大的高山草甸生态系统所在地。它被认为极易受到全球变暖的影响。了解过去在类似温暖气候下的植被动态，有助于洞察生态系统转变的临界点可能在哪里。我们报告了从青藏高原东部若尔盖盆地（海拔约3350 - 3450米）获取的湖泊沉积岩芯中过去350万年连续的、具有百年分辨率的花粉记录。利用生物分类、数值分析、统计建模和植被模拟等方法，它揭示了不同时间尺度上植被动态的详细情况。这些证据表明，植被经历了从上新世中晚期（350 - 273万年前）稳定的森林，到第四纪早期（273 - 154万年前）森林和草原共占主导，再到约154万年后以草甸为主的生态系统的转变，同时伴随着冰期 - 间冰期以及千年尺度的草原 - 森林更替。这些植被变化在很大程度上受温度变化控制。全球变暖约2 - 3°C是青藏高原森林扩张和草甸恢复力丧失的最重要阈值。类比过去，我们认为，如果不大幅减少温室气体排放，当前青藏高原的草甸面临着重大转变的风险。
