关键词: 高寒草甸, 地下芽库, 气候变化, 植物功能群, 种群更新

Abstract: Global warming has profound influences on the structure and function of terrestrial ecosystems. However, the responses of bud bank and its contribution to population regeneration in alpine meadows to global warming have not yet been clarified. In this study, we examined the effects of long-term (12 years) warming on the belowground bud bank and its relationship with aboveground shoot population of whole plant community and key plant functional groups in the alpine meadow of Qinling Mountains, using open-top growth chamber (OTC) to simulate the scenario of climate warming. Results showed that simulated warming reduced belowground bud density and shoot density of the whole community by 42% (P=0.065) and 45.5% (P<0.05), respectively, but had little influences on the number of buds per shoot (i.e., the ratio of bud to shoot density). Different plant functional groups showed varied responses to warming. Warming significantly reduced the belowground bud density and the number of buds per shoot (P<0.05), while did not affect shoot density of forbs. Warming had no influences on the belowground bud density, but significantly reduced shoot density of rhizomatous grasses (P<0.05). In contrast, the belowground bud density, aboveground shoot density, and bud number per shoot of bunchgrasses showed no responses to warming (P>0.05). Our results indicate that climatic warming tends to suppress population regeneration via reducing belowground bud bank, and will potentially influence community structure and ecosystem function of alpine meadows by altering the population regeneration of different plant functional groups.

Key words: alpine meadow, belowground bud bank, climate change, plant functional group, population regeneration