Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes
Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes
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DOI：
10.1111/j.1461-0248.2007.01051.x
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发表时间：
2007-07-01
期刊：
影响因子：
8.8
通讯作者：
Zhao, Xinquan
中科院分区：
文献类型：
--
作者：
Cornelissen, Johannes H. C.;van Bodegom, Peter M.;Zhao, Xinquan
气候变化是否会将冷生物群落从大型长期碳汇转变为碳源，这是一个激烈的争论，因为生态系统介导的反馈对全球气候的巨大潜力。关键是植物凋落物分解的气候响应的方向、大小和一般性。在这里，我们提出了第一个定量分析的主要气候变化相关的驱动程序的凋落物分解率在寒冷的北方世界各地的生物群系。在两个对比鲜明的北极生命带中，同时培养了33个全球变化操纵实验中的环北极高山生态系统中的优势种的叶凋落物。我们表明，长期的，大规模的变化，落叶分解将主要由直接变暖的影响和随之而来的植物生长形式组成的变化，与一个小得多的作用，物种内的凋落物质量的变化。具体来说，气候变暖导致的寒冷生物群落中具有顽固落叶的灌木的持续扩张将构成对全球变暖的负反馈。根据其他（以前报道）的灌木扩张对土壤碳周转的正反馈的强度，这可能会部分抵消直接变暖增强凋落物分解。
Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide. Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.