青藏高原气候变化与高寒草地

The climate change and alpine grassland on the Tibetan Plateau

关键词:  青藏高原  气候变化  高寒草地  植被分布  物候  生产力  土壤碳库

Key words:  Tibetan Plateau  climate change  alpine grassland  vegetation distribution  phenology  plant production  soil carbon

摘要:

综述了近五十年来青藏高原气候和高寒草地的变化趋势,阐述了气候变化对高寒草地的可能影响。气候变化主要通过水、热过程及其诱导的环境变化对青藏高原高寒草地产生显著的影响。主要过程包括:气候变化对气候带、植被带、植物、植物群落、农业生产以及生态系统固碳潜力等的影响。从目前的观测和研究结果来看,有关青藏高原气候变化及其对高寒草地的可能影响都还很难得出一致的结论。因此,如何科学评价气候变化及其预测和评价对高寒草地结构和功能的潜在影响,以及如何将已经发生的变化纳入到全球变化模型或评价体系中,以便更加精确地评估气候变化的长期影响,将成为必须要回答的关键科学问题。

Abstract:

The paper systematically summarized the tendency of climate change and its potential effects on alpine grassland of Tibetan Plateau nearly past 50 years. The data showed that the magnitude of temperature increase on the Tibetan plateau was significantly greater than the average level of China even the world. Although the annual total precipitation tended to increase,the spatial and temporal variations were high from Southern to Northern and from Western to Eastern of the plateau. The climate changes significantly affected the alpine grassland of the Tibetan Plateau. The results from observations and simulations indicated that:(1)The climate zones and vegetation zones of Tibet Plateau could move to northward and westward,whereas the variation tendency of different vegetation areas depended on the different scenarios simulated by different models;(2)Rising temperatures advanced green-up and delayed yellow period from observations which prolonged growing seasons,but remote sensing data showed opposite results since the end of 1990s;(3)Species richness decreased and species composition changed;(4)the vegetation coverage and NPP enhanced from simulated scenarios,but opposite results were found from OTC experiments in the region;(5)Although prolong growing season may improve plant production,the risk of natural disasters could also increase for forages and crops;(6)The future climate change may has a little effect on soil carbon source/sink through simulated different scenarios. Based on the review,we found that generally there were inconsistent results about the climate change and its potential effects on alpine grassland so far on the Tibetan plateau. Therefore,it is necessary for us to research how observed temperature increase to affect structures and functions of the alpine system,and how to bring the generated changes into global change models or evaluation systems,in order to accurately evaluate the long-term effects of climate change in the region.The paper systematically summarized the tendency of climate change and its potential effects on alpine grassland of Tibetan Plateau nearly past 50 years. The data showed that the magnitude of temperature increase on the Tibetan plateau was significantly greater than the average level of China even the world. Although the annual total precipitation tended to increase,the spatial and temporal variations were high from Southern to Northern and from Western to Eastern of the plateau. The climate changes significantly affected the alpine grassland of the Tibetan Plateau. The results from observations and simulations indicated that