Functional microbial diversity in regenerating cutover peatlands responds to vegetation succession

Authors

  • Rebekka R. E. Artz,

    Corresponding author
    1. Macaulay Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK;
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  • Stephen J. Chapman,

    1. Macaulay Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK;
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  • Andy Siegenthaler,

    1. Wetlands Research Group, Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Station 2, CH-1015 Lausanne, Switzerland;
    2. Laboratory of Ecological Systems, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, CH-1015 Lausanne-Ecublens, Switzerland;
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  • Edward A. D. Mitchell,

    1. Wetlands Research Group, Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Station 2, CH-1015 Lausanne, Switzerland;
    2. Laboratory of Ecological Systems, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, CH-1015 Lausanne-Ecublens, Switzerland;
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  • Alexandre Buttler,

    1. Restoration Ecology Research Group, Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Station 2, CH-1015 Lausanne, Switzerland;
    2. Laboratory of Ecological Systems, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, CH-1015 Lausanne-Ecublens, Switzerland;
    3. Laboratoire de Chronoécologie, Université de Franche-Comte, La Bouloie, 25030 Besancon CEDEX, France;
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  • Estelle Bortoluzzi,

    1. Laboratoire de Chronoécologie, Université de Franche-Comte, La Bouloie, 25030 Besancon CEDEX, France;
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  • Daniel Gilbert,

    1. Laboratoire de Chronoécologie, Université de Franche-Comte, La Bouloie, 25030 Besancon CEDEX, France;
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  • Mika Yli-Petays,

    1. Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014, Helsinki;
    2. Parkano Research Unit, Finland & Finnish Forest Research Institute, Kaironiementie 54, FI-39700 Parkano, Finland; and
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  • Harri Vasander,

    1. Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014, Helsinki;
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  • André-Jean Francez

    1. UMR-CNRS ECOBIO no. 6553, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes CEDEX, France
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*Correspondence author. E-mail: r.artz@macaulay.ac.uk

Summary

  • 1While establishment of vegetation is the most visual indicator of regeneration on cutover peatland, the reinstatement of belowground functions is less well understood. Vegetation succession results in differences in peat quality in terms of C availability. The respiratory response of the soil microbial community to ecologically relevant substrates (community-level physiological profile, CLPP) such as those found in rhizosphere exudates and litter hydrolysates, is thought to reflect the activity and functional diversity of the soil microbial community, especially those involved in turnover of soluble photosynthate-derived C.
  • 2The relationship between CLPP and typical regeneration stages was investigated at five European peatlands, each with up to five sites representing a gradient of natural regeneration stages. We aimed to determine whether unaided revegetation consistently affected soil microbial CLPP, which environmental factors explained variation in CLPP on the scale of individual peatlands, and if these factors were consistent across different peatlands.
  • 3Within each peatland, a decomposition index based on diagnostic bands in Fourier transform-infrared spectra indicated that regeneration had generally started from a common base and that the influence of vegetation on the decomposition index declined with depth. In parallel, differences in vegetation cover between regeneration stages resulted in significantly different CLPP, but this effect decreased rapidly with soil depth. The magnitudes of the effect of vegetation succession versus soil depth appeared to be linked with the age range of the regeneration gradients. Hence, the effect of vegetation on CLPP is effectively diluted due to the remaining organic matter. Specific plant species described significant proportions of CLPP variability but these species were not consistent across peatland types. The effects of soil depth appeared to be peatland-specific.
  • 4Synthesis and applications. Together, the results indicate significant responses of the microbial community to vegetation succession, with the strength of the effect probably dependent on quantities of labile C allocation to the soil microbial community. Therefore, particularly in the early stages of regeneration of cutover peatlands, CLPP could provide vital information about the relative importance of different plant functional types on potential rates of labile C turnover.

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