Abstract: To explore the effects of global warming on the alpine meadows of the Qinghai-Tibet Plateau,an asymmetric seasonal simulated warming was carried out by means of open-top chambers(OTC) heating,and three sets of different seasonal warming treatments were set up,including annual warming (T1),summer,autumn,and winter warming (T2),spring,summer,and autumn warming (T3). The effects of different seasons on community composition and community characteristics were analyzed. The results showed that the dominant species of the community changed after warming;the average height of the community increased,of which the average height of the communities of T1 and T3 increased significantly;there was no significant change in the average coverage of the community,but the height and coverage of Gramineae increased after warming treatment. The Patrick richness,Shannon-Wiener diversity index,and Simpson dominance index of the warming community in different seasons all changed to varying degrees,while the Pielou uniformity index did not change significantly,which showed that the community richness,diversity index,and dominance index of T1 were significantly reduced,the richness and dominance index of T3 were significantly reduced. Alpine meadow plant communities respond differently to different warming treatments.

Key words: Alpine meadow, Seasonal asymmetric warming, OTC, Community characteristics

摘要： 为探究全球气候变暖对青藏高原高寒草甸的影响，本文采用开顶式生长室(Open-top chambers，OTC)增温方式进行不对称季节性模拟增温，设置全年增温(T1)、夏秋冬季增温(T2)和春夏秋季增温(T3)3组不同处理，分析高寒草甸的群落组成及群落特征的变化。结果表明，增温后群落的优势种发生变化；群落的平均高度增加，其中T1和T3处理的群落平均高度显著增加；群落平均盖度无显著变化，但禾本科植物的高度和盖度增加；不同季节增温后群落的Patrick丰富度、Shannon-Wiener多样性指数、Simpson优势度指数均有不同程度的变化，Pielou均匀度指数则无明显变化，表现为T1处理的群落丰富度、多样性指数和优势度指数显著降低，T3处理的丰富度和多样性指数显著降低。高寒草甸植物群落对不同季节增温处理的响应程度有所不同。

关键词: 高寒草甸, 季节性不对称增温, OTC, 群落特征