摘要
Asymmetric seasonal warming,characterized by more pronounced temperature increases in winter than in summer,has become a critical feature of global warming,especially in cold and high-altitude regions.Previous studies have primarily focused on year-round warming,while comparatively less attention was paid to winter warming.However,a significant knowledge gap exists regarding the impacts of winter warming on ecosystem functions.To address this,we conducted an 8-year manipulated warming experiment in an alpine grassland on the Tibetan Plateau,employing three treatments:no warming,year-round warming and winter warming.We found that neither year-round warming nor winter warming significantly alters species richness at the community level.Notably,community biomass stability was maintained via species asynchrony.However,warming exerted significant effects on the plant abundance groups(dominant,common and rare species).Specifically,winter warming enhanced the stability of dominant species by increasing species asynchrony of dominant species,as the compensatory dynamics occurred between the grass and forbs.In contrast,year-round warming reduced the stability of common species,correlated with an increase in species richness and a decline in asynchrony among common species.Thus,our study underscores the capacity of alpine grassland to maintain community biomass stability via asynchrony dynamics of species under different warming conditions,although the stability of different abundance groups would be changed.Importantly,our results provide valuable insights for understanding the alpine grassland ecosystem on the Tibetan Plateau.
不对称季节性增温,即冬季的温度增加明显高于夏季,已成为全球变暖的一个重要特征,尤其在寒冷和高海拔地区。过去的研究主要关注全年的温度增高,而对冬季增温的关注相对较少。然而,关于冬季增温对生态系统功能的影响存在显著的知识空缺。为了解决这个问题,我们在青藏高原的高寒草甸进行了为期8年的控制增温实验,设置3种处理:自然对照、全年增温和冬季增温。结果发现,无论是全年增温还是冬季增温都没有显著改变群落水平的物种丰富度。值得注意的是,通过物种异步性,群落生物量的稳定性得以维持。然而,增温对植物丰度组(优势种、常见种和稀有种)产生了显著影响。具体而言,冬季增温增强了优势种的稳定性,这是通过增加优势种的物种异步性,即禾本科植物和非禾本科杂草植物之间发生了补偿动态来实现的。相反,全年增温降低了常见种的稳定性,这与常见种丰富度的增加和常见种中异步性的下降相关。因此,本研究强调了高寒草甸在不同增温条件下通过物种异步动态来维持群落生物量稳定性的能力,这些研究结果为理解青藏高原高寒草甸生态系统特征提供了新见解。
基金
the National Natural Science Foundation of China(U20A2009,41991234,42077422 and 41725003)
the National Key Research and Development Program of China(2022YFF1301801)
the Major Science and Technology Projects in Tibet(XZ202101ZD0007G and XZ202101ZD0003N).
