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Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses: a meta-analysis
Auteur(s)
Limpens, J.
Granath, G.
Gunnarsson, U.
Aerts, R.
Bayley, S.
Bragazza, Luca
Bubier, J.
Buttler, Alexandre
van den Berg, L. J. L.
Francez, Andre-Jean
Gerdol, R.
Grosvernier, Philippe
Heijmans, M. M. P. D.
Hoosbeek, M. R.
Hotes, S.
Ilomets, M.
Leith, I.
Moore, T.
Nilsson, Mats B.
Nordbakken, J. F.
Rochefort, L.
Rydin, H.
Sheppard, L. J.
Thormann, M.
Wiedermann, M. M.
Williams, B. L.
Xu, B.
Date de parution
2011
In
New Phytologist
Vol.
2
No
191
De la page
496
A la page
507
Résumé
Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased annual precipitation intensified the negative effects of N. The temperature effect was comparable to an experimental application of almost 4 g N m(-2) yr(-1) for each 1 degrees C increase. Our results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation.
Identifiants
Type de publication
journal article
