Root traits predict decomposition across a landscape-scale grazing experiment.
Bottom Line: Large herbivores can potentially influence below-ground decomposition through changes in soil microclimate (temperature and moisture) and changes in plant species composition (root traits).Supporting this, in microcosms, roots with lower specific root area (m(2) g(-1)) or those with higher phosphorus concentrations decomposed faster.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.
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.Show MeSH
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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).
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.