高寒草地紫外辐射的时间变动特征与UVA、UVB增加对植物与生态系统功能的影响

近十来年，越来越多的研究发现，紫外辐射的UV-A和UV-B对生态系统功能有复杂而多样的影响。在全球范围内，青藏高原是紫外辐射最强烈的地区之一，而且季节变化最大，强紫外辐射覆盖的面积最广，未来变化的不确定性也很高。但是，有关该高原紫外辐射环境的长期地面观测很少，就紫外辐射对生态系统影响的研究就更少。本研究将利用并继续在海北高寒草地的UV-A和UV-B长期观测，进行紫外辐射增加实验。本研究的问题是，青藏高原紫外辐射的时间动态特征是什么？不同波长的紫外辐射的增加对高山植物的光合特性、草地生态系统功能有何影响？该研究将揭示并预测UV-A和UV-B在不同时间尺度上的动态变化，探讨典型高山植物的光合碳同化特性、草甸生态系统的主要功能（植物群落的光合与呼吸）对UV-A、UV-B单独增加以及同时增加的响应。其结果将从紫外辐射这一新的角度理解青藏高原草地生态系统，并为高寒草地管理等提供信息支持。

Over the last decade, growing evidence indicates that UV-A (Ultraviolet-A) UV-B have widespread and significant impacts on various ecosystems. The Qinghai-Tibetan Plateau is the most extensive area with the strongest UV radiation intensity combing with the largest UV seasonality in the world. However, little information is available, either on the long-term ground observation, or on the effects of UV radiation on ecosystem structure and function. We will continue a long-term ground observation on the solar UV-A and UV-B in an alpine meadow, to examine the temporal variability of the two UV components in relation to other environmental conditions including radiation components and sky conditions. Moreover, we will conduct a manipulation experiment with UV-A and UV-B additions, both combined and independently, to understand the effects of UV radiation on the ecosystem properties including leaf traits, photosynthesis, plant biomass growth and carbon budget. The results will provide insights into our further understanding on the structure and function of the unique plateau ecosystem in the world, and also provide supporting information for the management of the alpine meadow.