Abstract
Summary
Root litter is the dominant soil carbon and nutrient input in many ecosystems, yet few studies have considered how root decomposition is regulated at the landscape scale and how this is mediated by land-use management practices. Large herbivores can potentially influence below-ground decomposition through changes in soil microclimate (temperature and moisture) and changes in plant species composition (root traits).
To investigate such herbivore-induced changes, we quantified annual root decomposition of upland grassland species in situ across a landscape-scale livestock grazing experiment, in a common-garden experiment and in laboratory microcosms evaluating the influence of key root traits on decomposition.
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. Species-specific decomposition rates were similar across all grazing treatments, and species differences were maintained in the common-garden experiment, suggesting an overriding importance of litter type. Supporting this, in microcosms, roots with lower specific root area (m2 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.
Root litter is the dominant soil carbon and nutrient input in many ecosystems, yet few studies have considered how root decomposition is regulated at the landscape scale and how this is mediated by land-use management practices. Large herbivores can potentially influence below-ground decomposition through changes in soil microclimate (temperature and moisture) and changes in plant species composition (root traits).
To investigate such herbivore-induced changes, we quantified annual root decomposition of upland grassland species in situ across a landscape-scale livestock grazing experiment, in a common-garden experiment and in laboratory microcosms evaluating the influence of key root traits on decomposition.
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. Species-specific decomposition rates were similar across all grazing treatments, and species differences were maintained in the common-garden experiment, suggesting an overriding importance of litter type. Supporting this, in microcosms, roots with lower specific root area (m2 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.
| Original language | English |
|---|---|
| Pages (from-to) | 851-862 |
| Number of pages | 12 |
| Journal | New Phytologist |
| Volume | 203 |
| Issue number | 3 |
| Early online date | 20 May 2014 |
| DOIs | |
| Publication status | Published - Aug 2014 |
Bibliographical note
AcknowledgementsWe are grateful to the Woodland Trust for maintenance of and access to the Glen Finglas experiment. We thank Debbie Fielding, William Smith, Sarah McCormack, Allan Sim, Marcel Junker and Elaine Runge for help in the field and the laboratory.
This research was part of the Glen Finglas project (formerly Grazing and Upland Birds (GRUB)) funded by the Scottish Government (RERAS). S.W.S. was funded by a BBSRC studentship.
Keywords
- carbon (C)
- grassland
- grazing
- nitrogen (N)
- plant traits
- root decomposition
- soil moisture
- soil temperature
Access to Document
- Root traits predict decomposition across a landscape-scale grazing experiment
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