The sensitivity of peatland carbon (C) fluxes to changes in climate and hydrology are uncertain due to the complex interactions between plants and peat properties. In this study we examine how peat cores taken from under three plant functional types (PFT) (bryophyte, graminoid and ericoid) differ in their biotic and abiotic properties and how this indirectly modulates the response of C fluxes to environmental change. Peat cores taken from under three PFTs had their aboveground vegetation removed to exclude direct plant‐mediated effects, and were incubated in a temperature × water table factorial experiment at 12, 14 and 16°C (air temperature) with the water table level −25, −15 or −5 cm below the peat surface. Carbon dioxide (CO₂) and methane (CH₄) fluxes were measured over 11 months. Emissions of CO₂ and CH₄ increased with temperature, with strong positive (CH₄) and negative (CO₂) interactions with increasing water table level. There were significant effects of removed PFT on the environmental sensitivity of CH₄, but not CO₂ fluxes. CH₄ emissions were greatest in peat with graminoid PFT removed at the warmest temperature but these indirect effects were not explained by peat abiotic or biotic properties, which did not differ between PFTs. These results show that climate change‐induced expansion of graminoids in northern peatlands will have direct and indirect effects on C fluxes and the stability of peatland C stores. These responses will be determined by the interactive effects of vegetation composition, hydrology and warming on methane‐cycling microbial communities.

中文翻译：

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植物功能类型间接影响泥炭地碳通量及其对环境变化的敏感性

由于植物与泥炭特性之间的复杂相互作用，泥炭地碳（C）通量对气候和水文变化的敏感性尚不确定。在这项研究中，我们研究了从三种植物功能类型（PFT）（苔藓植物，类蠕虫和类固醇）中提取的泥炭芯在生物和非生物特性上的差异，以及这如何间接调节碳通量对环境变化的响应。取自三个PFT下的泥炭芯，去除了地上植被，以排除植物直接介导的影响，并在温度×地下水析因实验中于12、14和16°C（气温）下以地下水位-25进行温育。在泥炭表面以下-15或-5厘米处。二氧化碳（CO ₂）和甲烷（CH ₄）在11个月内测量了通量。随着温度的升高，CO ₂和CH _4的排放量增加，并且随着地下水位的升高，强烈的正（CH ₄）和负（CO ₂）相互作用。PFT的去除对CH ₄的环境敏感性有显着影响，而对CO _2的通量则无影响。通道₄泥炭的排放量最大，在最热的温度下去除了类人似的PFT，但这些间接影响没有用泥炭的非生物或生物特性来解释，这在PFT之间没有区别。这些结果表明，气候变化导致的泥炭地北部类动物类动物的膨胀将对碳通量和泥炭地C储量的稳定性产生直接和间接的影响。这些反应将取决于植被组成，水文学和变暖对甲烷循环微生物群落的相互作用。