Climate change drives a shift in peatland ecosystem plant community: Implications for ecosystem function and stability
Climate change drives a shift in peatland ecosystem plant community: Implications for ecosystem function and stability
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DOI：
10.1111/gcb.12643
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发表时间：
2015-01-01
影响因子：
11.6
通讯作者：
Lindo, Zoe
中科院分区：
文献类型：
--
作者：
Dieleman, Catherine M.;Branfireun, Brian A.;Lindo, Zoe
泥炭地植物群落的组成对一系列生态系统功能具有重要影响。预测未来气候变化下泥炭地植物群落结构将发生变化，量化这种变化的方向和幅度是研究的重点。为了确定气候变化因素对贫瘠沼泽植物群落组成的个体效应和协同效应，我们采用因子设计，将完整的、复制的贫瘠沼泽泥炭单体置于升高的温度、增加的大气二氧化碳（CO2）和两个地下水位下。我们确定了气候变化条件下实验贫沼系统中发生的制度转变的三个指标：在温度高于环境条件8℃时，Sphagnum的非线性下降；在温度高于环境条件4℃时，苔属植物的增加表明Sphagnum对泥炭积累的反馈减弱；随着时间的推移，植物群落组成和孔隙水pH值的变化增加。温度升高+4℃似乎是维管植物丰度增加的阈值；然而，变化的幅度是物种依赖的。升高的温度和升高的CO2对大型禾本科植物种类丰度具有协同效应，与对照条件相比增加了15倍。群落分析表明，在气候变化因素的共同作用下，优势种间的平衡由泥炭属植物向禾本科植物为主系统倾斜。我们的研究结果表明，在未来的气候变化条件下，泥炭地植物群落组成可能会发生变化，在贫瘠的沼泽中，禾草类植物将占据优势地位。
The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO2), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 degrees C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 degrees C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 degrees C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO2 had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid-dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens.