Voici les éléments 1 - 2 sur 2
  • Publication
    Métadonnées seulement
    Contrasted effects of increased N and CO2 supply on two keystone species in peatland restoration and implications for global change
    (2002-5-2) ;
    Buttler, Alexandre
    ;
    Grosvernier, Philippe
    ;
    Rydin, Hakan
    ;
    Siegenthaler, Andy
    ;
    1 Significant areas of temperate bogs have been damaged by peat harvesting but may regenerate. These secondary mires, if well managed, may act as strong C sinks, regulate hydrology and buffer regional climate. 2 The potential effects of bog regeneration will, however, depend on the successful establishment of the principal peat formers - Sphagnum mosses. The influence of hydrology and microclimate on Sphagnum re-growth is well studied but effects of elevated CO2 and N deposition are not known. 3 We carried out two in-situ experiments in a cutover bog during three growing seasons in which we raised either CO2 (to 560 p.p.m.) or N (by adding NH4NO3, 3 g m(-2) year(-1)). The two treatments had contrasting effects on competition between the initial coloniser Polytrichum strictum (favoured by high N) and the later coloniser Sphagnum fallax (favoured by high CO2). 4 Such changes may have important consequences for bog regeneration and hence for carbon sequestration in cutover bogs, with potential feedback on regional hydrological and climatic processes.
  • Publication
    Métadonnées seulement
    Effects of elevated atmospheric CO2 and mineral nitrogen deposition on litter quality, bioleaching and decomposition in a sphagnum peat bog
    (: Springer, 1999-5-2)
    Siegenthaler, Andy
    ;
    ;
    Van der Heijden, Edvin
    ;
    Buttler, Alexandre
    ;
    Grosvernier, Philippe
    ;
    ;
    Visconti, Guido
    ;
    Beniston, Martin
    ;
    Iannorelli, Emilio D
    ;
    Barba, Diego
    A brief overview of an attempt to link the effect of elevated CO2 and nitrogen deposition on litter quality and decomposition in a Sphagnum peat bog is given. Litter of three common species (Eriophorum vaginatum, Polytrichum strictum and Sphagnum fallax) was collected from field plots after two years of pre-treatment in two parallel experiments: a) Elevated atmospheric CO2 experiment, b) mineral nitrogen fertilisation experiment. The litters were put into litterbags, leached and inserted into field plots for 3 months, where they decomposed under specific treatment. Distinction between effects of initial litter quality and decomposition on mass loss in the bioleaching and/or in field decomposition process could be tested using a particular set-up in which cross-effects of pre-treatment and treatment were considered.