Vegetation exerts a greater control on litter decomposition than climate warming in peatlands.
Vegetation exerts a greater control on litter decomposition than climate warming in peatlands.
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DOI：
10.1890/14-0292.1
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发表时间：
2015
期刊：
影响因子：
4.8
通讯作者：
Susan E. Ward;K. Orwin;K. Orwin;Nick Ostle;Maria J. I. Briones;B. Thomson;R. Griffiths;S. Oakley;H. Quirk;R. Bardgett;R. Bardgett
中科院分区：
文献类型：
--
作者：
Susan E. Ward;K. Orwin;K. Orwin;Nick Ostle;Maria J. I. Briones;B. Thomson;R. Griffiths;S. Oakley;H. Quirk;R. Bardgett;R. Bardgett
从历史上看，缓慢的分解速度导致了北方泥炭地大量碳的积累。气候变暖和植被变化都可以改变分解率，从而影响大气中二氧化碳的交换率，对气候变化的反馈产生影响。虽然变暖和植被变化正在同时发生，但人们对它们对分解过程的相对和相互作用的影响知之甚少。为了测试气候变暖和植被变化对分解速率的影响，我们将三种优势物种（Calluna vulgaris，Eriophorum vaginatum，Hypnum jutlandicum）的凋落物放入泥炭地田间实验，该实验将气候变暖与植物功能群去除相结合，并测量了两年多的质量损失。为了确定影响背后的潜在机制，我们还测量了养分循环和土壤生物群。我们发现，植物功能组去除施加了更强的控制短期凋落物分解比约1摄氏度变暖，植物去除效果取决于凋落物物种的身份。具体而言，凋落物分解速度更快，灌木被从植物群落中删除时，这些影响是最强的禾本科和brancte凋落物。植物功能团的去除也有很强的影响，土壤生物群和养分循环与分解，灌木去除土壤真菌群落组成，增加enchytraeid丰度，并增加氮矿化率的级联效应。我们的研究结果表明，除了凋落物质量，植被组成的变化在调节短期凋落物分解和泥炭地地下群落中发挥了重要作用，这些影响可能大于中度变暖效应。我们的研究结果，虽然从一个相对短期的研究，强调需要考虑植被变化及其对地下的影响，以及气候影响时，预测未来的分解率和碳储存在泥炭地。
Historically, slow decomposition rates have resulted in the accumulation of large amounts of carbon in northern peatlands. Both climate warming and vegetation change can alter rates of decomposition, and hence affect rates of atmospheric CO2 exchange, with consequences for climate change feedbacks. Although warming and vegetation change are happening concurrently, little is known about their relative and interactive effects on decomposition processes. To test the effects of warming and vegetation change on decomposition rates, we placed litter of three dominant species (Calluna vulgaris, Eriophorum vaginatum, Hypnum jutlandicum) into a peatland field experiment that combined warming.with plant functional group removals, and measured mass loss over two years. To identify potential mechanisms behind effects, we also measured nutrient cycling and soil biota. We found that plant functional group removals exerted a stronger control over short-term litter decomposition than did approximately 1 degrees C warming, and that the plant removal effect depended on litter species identity. Specifically, rates of litter decomposition were faster when shrubs were removed from the plant community, and these effects were strongest for graminoid and bryophyte litter. Plant functional group removals also had strong effects on soil biota and nutrient cycling associated with decomposition, whereby shrub removal had cascading effects on soil fungal community composition, increased enchytraeid abundance, and increased rates of N mineralization. Our findings demonstrate that, in addition to litter quality, changes in vegetation composition play a significant role in regulating short-term litter decomposition and belowground communities in peatland, and that these impacts can be greater than moderate warming effects. Our findings, albeit from a relatively short-term study, highlight the need to consider both vegetation change and its impacts below ground alongside climatic effects when predicting future decomposition rates and carbon storage in peatlands.