Robroek Bjorn J M, Jassey Vincent E J, Beltman Boudewijn, Hefting Mariet M
Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK.
INP, UPS, CNRS, Laboratoire d'Ecologie Fonctionnelle et Environnement (Ecolab), Université de Toulouse, 31062 Toulouse Cedex, France.
R Soc Open Sci. 2017 Oct 25;4(10):170449. doi: 10.1098/rsos.170449. eCollection 2017 Oct.
Global change, like droughts, can destabilize the carbon sink function of peatlands, either directly or indirectly through changes in plant community composition. While the effects of drought and plant community composition on individual carbon (C) related processes are well understood, their effect on multiple C-related processes simultaneously-multifunctionality-is poorly known. We studied the effect of drought on four C-related processes (net and gross CO exchange, methane fluxes, and dissolved organic carbon content) in a plant removal experiment. Plant functional type (PFT) removal (graminoids, herbs, spp., incl. combinations) negatively affected multifunctionality; most markedly when all PFTs were removed. Our results corroborate a negative drought effect on C-related multifunctionality. Drought reduced multifunctionality, and this reduction was again largest when all PFTs were removed. Our data further indicate that much of these negative drought effects were carried over and maintained from the initial removal treatment. These results suggest that while a high diversity in plant functional types is associated to high C-related multifunctionality, plant community assembly does not drive the ability of peatlands to withstand the negative impacts of drought on multifunctionality. Hence, to safeguard the carbon cycling function in intact peatlands, the effects of climate change on the functional composition of the peatland plant community needs to be minimized.
全球变化，如干旱，会直接或通过植物群落组成的变化间接破坏泥炭地的碳汇功能。虽然干旱和植物群落组成对单个碳（C）相关过程的影响已为人熟知，但其对多个C相关过程同时产生的影响——多功能性——却鲜为人知。我们在一项植物去除实验中研究了干旱对四个C相关过程（净CO₂和总CO₂交换、甲烷通量以及溶解有机碳含量）的影响。去除植物功能类型（PFT）（禾本科植物、草本植物、莎草科植物，包括组合）对多功能性产生了负面影响；当所有PFT都被去除时影响最为显著。我们的结果证实了干旱对C相关多功能性有负面影响。干旱降低了多功能性，并且当所有PFT都被去除时这种降低再次最为明显。我们的数据进一步表明，这些干旱的负面影响大多是从最初的去除处理延续并维持下来的。这些结果表明，虽然植物功能类型的高度多样性与高C相关多功能性相关，但植物群落组装并不能驱动泥炭地抵御干旱对多功能性负面影响的能力。因此，为了保护完整泥炭地的碳循环功能，需要尽量减少气候变化对泥炭地植物群落功能组成的影响。
