非生长季降水对青藏高原高寒草甸优势种生物量稳定性的影响

受全球气候变化的影响，青藏高原在过去的几十年间整体上呈现暖湿化的趋势，相比于年际之间温度和降水的变化外，生长季和非生长季气候变化模式的差异可能会对生态系统产生更重要的影响，但相关的研究尚不充分。以青藏高原东部的高寒草甸为研究对象，基于2001年至2017年17年的野外观测数据，包括优势植物紫花针茅的高度、多度以及生物量、次优势物种洽草的生物量，结合生长季和非生长季平均温度和降水量的变化，通过线性回归以及结构方程模型，探究生长季/非生长季不对称气候变化对于青藏高原高寒草甸优势物种生物量稳定性的影响。研究结果表明：1)青藏高原东部年均温和年降水在过去的17年间显著增加，呈现暖湿化的趋势，但是非生长的降水却变化不明显；2)紫花针茅的高度、多度以及生物量在过去17年没有显著的趋势，但是洽草的生物量稳定性显著减少；3)非生长降水结合紫花针茅的高度、多度以及洽草的生物量稳定性促进了紫花针茅的生物量稳定性。研究结果可以为青藏高原高寒草甸在未来气候变化的背景下合理保护与利用提供科学依据。

Non-growing season precipitation facilitated the biomass stability of dominant species in alpine meadow of the Qinghai Tibet Plateau

In the past few decades,the Qinghai-Tibet Plateau showed warming and humidifying with global climate change. Compared with the interannual changes of temperature and precipitation, the difference of climate change patterns between growing season and non-growing season may have a more important impact on the ecosystem, but the relevant research is still insufficient. Based on the field observation data of 17 years from 2001 to 2017, including the height, abundance and biomass of dominant plant Stipa purpurea, and biomass of Subdominant species Koeleria cristata, combined with the changes of mean temperature and precipitation in growing season and non-growing season, the growth season/non growing season was explored by linear regression and structural equation model to explore the effects of asymmetric climate change in growing season and non-growing season on biomass stability of dominant species in alpine meadow of Qinghai Tibet Plateau. The results show that:1) the annual mean temperature and annual precipitation in the eastern Tibetan Plateau have increased significantly in the past 17 years, showing a trend of warming and wetting, but the non-growing precipitation has no significant change; 2) The height, abundance and biomass of Stipa purpurea had no significant change trend in the past 17 years, but the biomass stability of Koeleria cristata decreased significantly; 3) The non-growth precipitation combined with the height and abundance of Stipa purpurea and the biomass stability of Koeleria cristata promoted the biomass stability of Stipa purpurea. The results can provide scientific basis for the reasonable protection and utilization of alpine meadow in the context of climate change in the future.