PDF(Pubmed)
Abstract：
Terrestrial wetland ecosystems challenge biodiversity-ecosystem function theory, which generally links high species diversity to stable ecosystem functions. An open question in ecosystem ecology is whether assemblages of co-occurring peat mosses contribute to the stability of peatland ecosystem processes. We conducted a two-species (Sphagnum cuspidatum, Sphagnum medium) replacement series mesocosm experiment to evaluate the resistance, resilience, and recovery rates of net ecosystem CO2 exchange (NEE) under mild and deep water table drawdown. Our results show a positive effect of mild water table drawdown on NEE with no apparent role for peat moss mixture. Our study indicates that the carbon uptake capacity by peat moss mixtures is rather resilient to mild water table drawdown, but seriously affected by deeper drought conditions. Co-occurring peat moss species seem to enhance the resilience of the carbon uptake function (i.e. ability of NEE to return to pre-perturbation levels) of peat moss mixtures only slightly. These findings suggest that assemblages of co-occurring Sphagnum mosses do only marginally contribute to the stability of ecosystem functions in peatlands under drought conditions. Above all, our results highlight that predicted severe droughts can gravely affect the sink capacity of peatlands, with only a small extenuating role for peat moss mixtures.
摘要：
陆地湿地生态系统挑战生物多样性-生态系统功能理论，这通常将高物种多样性与稳定的生态系统功能联系起来。生态系统生态学中的一个悬而未决的问题是，共生的泥炭苔藓的组合是否有助于泥炭地生态系统过程的稳定性。我们进行了两个物种(虎尾草，泥炭藓培养基）替代系列介观实验，以评估阻力，弹性，在轻度和深水位下降下，净生态系统CO2交换（NEE）的回收率。我们的结果表明，温和的地下水位下降对NEE有积极作用，对泥炭藓混合物没有明显作用。我们的研究表明，泥炭苔藓混合物的碳吸收能力对温和的水位下降相当有弹性，但受到更深的干旱条件的严重影响。共存的泥炭苔藓物种似乎仅略微增强了泥炭苔藓混合物的碳吸收功能（即NEE恢复到扰动前水平的能力）的弹性。这些发现表明，在干旱条件下，共同发生的泥炭藓苔藓的组合对泥炭地生态系统功能的稳定性仅有很小的贡献。最重要的是,我们的研究结果突出表明，预测的严重干旱会严重影响泥炭地的汇能力，对泥炭藓混合物只有很小的增容作用。
