Contrasting growth responses of dominant peatland plants to warming and vegetation composition
Contrasting growth responses of dominant peatland plants to warming and vegetation composition
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DOI：
10.1007/s00442-015-3254-1
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发表时间：
2015-02
期刊：
影响因子：
2.7
通讯作者：
Tom W. N. Walker;Susan E. Ward;N. Ostle;R. Bardgett
中科院分区：
文献类型：
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作者：
Tom W. N. Walker;Susan E. Ward;N. Ostle;R. Bardgett
越来越多的人认识到，植被组成的变化可以强烈地影响泥炭地的碳循环，并可能对未来气候产生反馈。然而，尽管该生态系统的气候和植被变化加速，泥炭地植物物种对增温和植被变化的生长响应尚不清楚。本文通过野外增温和植被去除实验，验证了三种植物功能类型（矮灌木：Calluna vulgaris；禾本科：Eriophorum vaginatum；苔藓植物：Sphagnum capillifolium）的优势种对增温和其他植物功能类型存在或不存在的生长响应差异的假设。升温采用开顶箱，将空气温度升高约0.35°C，我们测量了空气和土壤小气候作为这两个实验因素影响生长的潜在机制。我们发现，只有愈伤组织的生长随实验升温而增加（20%），而矮灌木和苔藓植物的存在分别增加了sphagnum（46%）和andEriophorum（20%）的生长。土壤温度与褐藻生长也呈负相关，矮灌木土壤温度较低。因此矮灌木可以通过冷却泥炭表面来促进氢氮的生长。相反，苔藓植物的存在对枇杷生长的影响与小气候的变化无关，表明有其他因素在起作用。总之，我们的研究结果揭示了泥炭地优势植物生长的非生物和生物控制差异，表明气候和植被的同时变化可能改变群落组成和碳循环。
There is growing recognition that changes in vegetation composition can strongly influence peatland carbon cycling, with potential feedbacks to future climate. Nevertheless, despite accelerated climate and vegetation change in this ecosystem, the growth responses of peatland plant species to combined warming and vegetation change are unknown. Here, we used a field warming and vegetation removal experiment to test the hypothesis that dominant species from the three plant functional types present (dwarf-shrubs:Calluna vulgaris; graminoids:Eriophorum vaginatum; bryophytes:Sphagnum capillifolium) contrast in their growth responses to warming and the presence or absence of other plant functional types. Warming was accomplished using open top chambers, which raised air temperature by approximately 0.35 °C, and we measured air and soil microclimate as potential mechanisms through which both experimental factors could influence growth. We found that onlyCallunagrowth increased with experimental warming (by 20 %), whereas the presence of dwarf-shrubs and bryophytes increased growth ofSphagnum(46 %) andEriophorum(20 %), respectively.Sphagnumgrowth was also negatively related to soil temperature, which was lower when dwarf-shrubs were present. Dwarf-shrubs may therefore promoteSphagnumgrowth by cooling the peat surface. Conversely, the effect of bryophyte presence onEriophorumgrowth was not related to any change in microclimate, suggesting other factors play a role. In conclusion, our findings reveal contrasting abiotic and biotic controls over dominant peatland plant growth, suggesting that community composition and carbon cycling could be modified by simultaneous climate and vegetation change.