Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Sustained impact of drought on wet shrublands mediated by soil physical changes
AU - Dominguez, Maria T.
AU - Sowerby, Alwyn
AU - Smith, Andrew R.
AU - Robinson, David A.
AU - Van Baarsel, Susie
AU - Mills, Robert
AU - Marshall, Miles R.
AU - Koller, Eva
AU - Lebron, Inma
AU - Hall, Jane
AU - Emmett, Bridget A.
PY - 2015/2
Y1 - 2015/2
N2 - Projected climate warming may substantially increase carbon emissions from wet organic soils, contributing to a positive feedback between the terrestrial carbon cycle and climate change. Evidence suggests that in these soils the stimulation of soil respiration by warming can be sustained over long periods of time due to the large availability of C substrates. However, the long-term response of wet organic soils to drought remains uncertain. Organo-mineral soils might be particularly vulnerable, because of their limited soil moisture pool to buffer drought events. Using a whole-ecosystem climate-change experiment in North Wales (UK) we show that soil respiration in podzolic (organo-mineral) soils from wet shrublands is more vulnerable to recurrent drought than to warming, and that the drought impact does not attenuate at decadal time scales. Stimulation of soil respiration by drought was linked to major changes in soil structure that led to a 54 % reduction in water holding capacity compared to control. Bryophyte abundance was found to buffer soil moisture losses, moderating soil CO2 efflux under warming. As there was no evidence of change in plant productivity to offset the increased soil C emissions under drought, this response may result in a positive climate feedback. The results indicate the potentially critical role that changes in sub-dominant vegetation and in soil physical properties may have in determining climate change impacts on soil C dynamics.
AB - Projected climate warming may substantially increase carbon emissions from wet organic soils, contributing to a positive feedback between the terrestrial carbon cycle and climate change. Evidence suggests that in these soils the stimulation of soil respiration by warming can be sustained over long periods of time due to the large availability of C substrates. However, the long-term response of wet organic soils to drought remains uncertain. Organo-mineral soils might be particularly vulnerable, because of their limited soil moisture pool to buffer drought events. Using a whole-ecosystem climate-change experiment in North Wales (UK) we show that soil respiration in podzolic (organo-mineral) soils from wet shrublands is more vulnerable to recurrent drought than to warming, and that the drought impact does not attenuate at decadal time scales. Stimulation of soil respiration by drought was linked to major changes in soil structure that led to a 54 % reduction in water holding capacity compared to control. Bryophyte abundance was found to buffer soil moisture losses, moderating soil CO2 efflux under warming. As there was no evidence of change in plant productivity to offset the increased soil C emissions under drought, this response may result in a positive climate feedback. The results indicate the potentially critical role that changes in sub-dominant vegetation and in soil physical properties may have in determining climate change impacts on soil C dynamics.
KW - Soil respiration
KW - Acclimation
KW - Water retention
KW - Warming
KW - Bryophyte
KW - Calluna vulgaris
KW - Soil structure
KW - CLIMATE-CHANGE EXPERIMENT
KW - CARBON-CYCLE FEEDBACK
KW - HETEROTROPHIC RESPIRATION
KW - TEMPERATURE SENSITIVITY
KW - TERRESTRIAL ECOSYSTEMS
KW - MICROBIAL COMMUNITY
KW - THERMAL-ACCLIMATION
KW - SUMMER DROUGHT
KW - HEATHLAND SOIL
KW - DECOMPOSITION
U2 - 10.1007/s10533-014-0059-y
DO - 10.1007/s10533-014-0059-y
M3 - Journal article
VL - 122
SP - 151
EP - 163
JO - Biogeochemistry
JF - Biogeochemistry
SN - 0168-2563
IS - 2-3
ER -