Growth and community responses of alpine dwarf shrubs to in situ CO₂ enrichment and soil warming.
Growth and community responses of alpine dwarf shrubs to in situ CO₂ enrichment and soil warming.
复制标题
高山矮灌木的生长和群落对原位二氧化碳富集和土壤变暖的响应。
作者：
M. A. Dawes;F. Hagedorn;T. Zumbrunn;I. Handa;S. Hättenschwiler;S. Wipf;C. Rixen
二氧化碳浓度上升和相关的全球变暖预计将对高海拔生态系统产生巨大影响，但在这些环境中进行长期多因素实验的情况很少。·我们调查了在瑞士阿尔卑斯山的树线上，落叶松和松树下层的主要矮灌木物种（欧洲越橘，欧洲越橘和欧洲越橘）的生长和群落组成对9年的CO 2富集和3年的土壤变暖的反应。欧洲越橘是唯一一个表现出明显的积极影响的物种，二氧化碳对生长的影响，随着时间的推移，每年的枝条生长反应没有下降。土壤变暖对欧洲葡萄生长的刺激作用甚至大于CO2浓度升高，并伴随着植物有效土壤氮（N）和叶片氮浓度的增加。通过对欧洲越桔和E.雌雄同体不受气候变暖的影响。维管植物物种丰富度下降，在CO2浓度升高的地块与落叶松，而苔藓和地衣物种的数量减少变暖。·持续的环境变化可能导致植物群落的多样性减少，并增加了特别敏感的V. myrtillus在研究的高山树线中的优势。这些变化是独立的二氧化碳和土壤变暖效应的结果，这一结果应有助于预测建模方法。
• Rising CO₂ concentrations and the associated global warming are expected to have large impacts on high-elevation ecosystems, yet long-term multifactor experiments in these environments are rare. • We investigated how growth of dominant dwarf shrub species (Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum) and community composition in the understorey of larch and pine trees responded to 9 yr of CO₂ enrichment and 3 yr of soil warming at the treeline in the Swiss Alps. • Vaccinium myrtillus was the only species that showed a clear positive effect of CO₂ on growth, with no decline over time in the annual shoot growth response. Soil warming stimulated V. myrtillus growth even more than elevated CO₂ and was accompanied by increased plant-available soil nitrogen (N) and leaf N concentrations. Growth of Vaccinium gaultherioides and E. hermaphroditum was not influenced by warming. Vascular plant species richness declined in elevated CO₂ plots with larch, while the number of moss and lichen species decreased under warming. • Ongoing environmental change could lead to less diverse plant communities and increased dominance of the particularly responsive V. myrtillus in the studied alpine treeline. These changes are the consequence of independent CO₂ and soil warming effects, a result that should facilitate predictive modelling approaches.