Mixture of plant functional groups inhibits the release of multiple metallic elements during litter decomposition in alpine timberline ecotone
Mixture of plant functional groups inhibits the release of multiple metallic elements during litter decomposition in alpine timberline ecotone
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DOI：
10.1016/j.scitotenv.2020.141298
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发表时间：
2020-12-10
影响因子：
9.8
通讯作者：
Liu, Yang
中科院分区：
文献类型：
--
作者：
Shen, Xian;Chen, Yamei;Liu, Yang
混合凋落物分解是自然界中的一种普遍现象，对生态系统中的物质循环非常重要。不同的植物官能团(PFG)在分解过程中可能会相互作用。目前尚不清楚混合分解如何影响多种金属元素的释放，高山生态系统中的生物地球化学循环机制也仍然难以捉摸。本研究在高山林线交错带进行了为期两年的混合枯枝落叶分解试验，试验地点为高山林线交错带。首先，结果表明，PFG特性对所有金属元素释放的影响比海拔更大。草类、落叶灌木和枯枝落叶中钾、钙、镁、铜的释放率显著高于常绿针叶、常绿灌木和混合凋落物。其次，混合凋落物分解过程中金属元素的释放呈现非加性效应。钾、钙、镁、钠(Na)、铜、铝(Al)表现出拮抗作用，而铁则表现出协同作用。对Na、K、Ca、Cu释放的拮抗作用随海拔升高而增强，对Mg、Al、Mn释放的拮抗作用随海拔升高而减弱。第三，Al和Fe表现出较高的积累水平。随着枯枝落叶向上移动，K的释放速率降低，Al和Fe的积累增加。总之，在高山林线交错带中，PFGs的混合物抑制了凋落物分解过程中多种金属元素的释放。我们推测，气候变暖引起的PFGs上升将减缓高山林线交错带K的释放，加速Fe和Al的富集化。(C)2020爱思唯尔B.V.保留所有权利。
Mixed litter decomposition is a common phenomenon in nature and is very important for the circulation of material through an ecosystem. Different plant functional groups (PFGs) are likely to interact during decomposition. It is unclear how mixed decomposition influences the release of multiple metallic elements, and the biogeochemical circulation mechanism in the alpine ecosystem remains elusive. In this study, a two-year experiment on decomposition of mixed litter from six dominant PFGs was conducted at two elevations in an alpine timberline ecotone using the litterbag method. First, the results suggested that PFG identity had greater impacts on the release of all metallic elements than elevation. The release rates of potassium (K), calcium (Ca), magnesium (Mg) and copper (Cu) in graminoid, deciduous shrub and for b litter were significantly higher than those in evergreen conifer, evergreen shrub and mixed litter. Second, the release of metallic elements showed non-additive effects during mixed litter decomposition. K, Ca, Mg, sodium(Na), Cu, and aluminium(Al) exhibited antagonistic effects, while Fe exhibited a synergistic effect. The antagonistic effects on Na, K, Ca and Cu release increased with increasing elevation, while the antagonistic effects on Mg, Al and Mn release decreased with increasing elevation. Third, Al and Fe showed high levels of accumulation. The K release rate decreased while Al and Fe accumulation increased with plant litter upward shift. In conclusion, mixtures of PFGs inhibits the release of multiple metallic elements during litter decomposition in the alpine timberline ecotone. We speculate that an upward shift in PFGs in response to climate warming will slow the release of K and accelerate the enrichment of Fe and Al in alpine timberline ecotones. (c) 2020 Elsevier B.V. All rights reserved.