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Root traits predict decomposition across a landscape-scale grazing experiment.

Smith SW, Woodin SJ, Pakeman RJ, Johnson D, van der Wal R - New Phytol. (2014)

Bottom Line: Livestock grazing increased soil temperatures, but this did not affect root decomposition.Grazing had no effect on soil moisture, but wetter soils retarded root decomposition.Our results suggest that large herbivores alter below-ground carbon and nitrogen dynamics more through their effects on plant species composition and associated root traits than through effects on the soil microclimate.

View Article: PubMed Central - PubMed

Affiliation: IBES, University of Aberdeen, St Machar Drive, Aberdeen, AB24 3UU, UK; The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK; ACES, University of Aberdeen, St Machar Drive, Aberdeen, AB24 3UU, UK.

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Conceptual diagram of the impact of livestock grazing on root decomposition, through grazing effects on soil microclimate (moisture and temperature) and species composition (i.e. root traits). Closed black arrows, significant direct effects (larger arrows indicate the increasing strength of that effect); dotted lines, measured nonsignificant direct effects; open arrow, unmeasured direct effects.
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fig05: Conceptual diagram of the impact of livestock grazing on root decomposition, through grazing effects on soil microclimate (moisture and temperature) and species composition (i.e. root traits). Closed black arrows, significant direct effects (larger arrows indicate the increasing strength of that effect); dotted lines, measured nonsignificant direct effects; open arrow, unmeasured direct effects.

Mentions: Although several studies have identified the importance of plant traits in explaining variation in microbial community composition at the landscape scale (De Vries et al., 2012) and leaf litter decomposition across varying intensities of land management (Garnier et al., 2004; Fortunel et al., 2009), our study provides new insights into how variation in plant traits acts on decomposition of root litter at the landscape scale and how this is mediated by grazing management practices. We used three complementary approaches to disentangle the potential effects of large herbivores on below-ground decomposition via possible changes in soil temperature, moisture and species composition (traits), thereby identifying the importance of litter identity in driving root decomposition. By quantifying root decomposition from 11 plant species in a controlled environment microcosm experiment, we identified specific traits that can predict root decomposition. In our upland grassland system, rates of root decomposition were dependent on litter identity and the underlying root traits – SRA and P concentration. Our results suggest that below-ground C and N dynamics in these upland grasslands will depend more on changes in plant species composition than on grazing-induced changes in soil microclimate (Fig. 5).


Root traits predict decomposition across a landscape-scale grazing experiment.

Smith SW, Woodin SJ, Pakeman RJ, Johnson D, van der Wal R - New Phytol. (2014)

Conceptual diagram of the impact of livestock grazing on root decomposition, through grazing effects on soil microclimate (moisture and temperature) and species composition (i.e. root traits). Closed black arrows, significant direct effects (larger arrows indicate the increasing strength of that effect); dotted lines, measured nonsignificant direct effects; open arrow, unmeasured direct effects.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260134&req=5

fig05: Conceptual diagram of the impact of livestock grazing on root decomposition, through grazing effects on soil microclimate (moisture and temperature) and species composition (i.e. root traits). Closed black arrows, significant direct effects (larger arrows indicate the increasing strength of that effect); dotted lines, measured nonsignificant direct effects; open arrow, unmeasured direct effects.
Mentions: Although several studies have identified the importance of plant traits in explaining variation in microbial community composition at the landscape scale (De Vries et al., 2012) and leaf litter decomposition across varying intensities of land management (Garnier et al., 2004; Fortunel et al., 2009), our study provides new insights into how variation in plant traits acts on decomposition of root litter at the landscape scale and how this is mediated by grazing management practices. We used three complementary approaches to disentangle the potential effects of large herbivores on below-ground decomposition via possible changes in soil temperature, moisture and species composition (traits), thereby identifying the importance of litter identity in driving root decomposition. By quantifying root decomposition from 11 plant species in a controlled environment microcosm experiment, we identified specific traits that can predict root decomposition. In our upland grassland system, rates of root decomposition were dependent on litter identity and the underlying root traits – SRA and P concentration. Our results suggest that below-ground C and N dynamics in these upland grasslands will depend more on changes in plant species composition than on grazing-induced changes in soil microclimate (Fig. 5).

Bottom Line: Livestock grazing increased soil temperatures, but this did not affect root decomposition.Grazing had no effect on soil moisture, but wetter soils retarded root decomposition.Our results suggest that large herbivores alter below-ground carbon and nitrogen dynamics more through their effects on plant species composition and associated root traits than through effects on the soil microclimate.

View Article: PubMed Central - PubMed

Affiliation: IBES, University of Aberdeen, St Machar Drive, Aberdeen, AB24 3UU, UK; The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK; ACES, University of Aberdeen, St Machar Drive, Aberdeen, AB24 3UU, UK.

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