Descripción
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We studied the effect ofmountain grassland afforestation with conifer trees (Pinus sylvestris, Picea abies and Pinus cembra) on soil organic matter (SOM) cycling and carbon (C) isotopic composition in two contrasting climate areas using a regional approach. Seventeen paired sites (each containing at least 40 years prior afforested and grassland plots) were investigated in themountains of Central Spain and Western Austria. Topsoil CO2 effluxes were monitored under standard- ized conditions for sixmonths as a proxy for soil organic carbon (SOC) mineralisation. The bulk C and nitrogen (N) concentrations and their isotopic composition in the soil and in the plants were assessed. The soil C:N ratio was consistently greater after afforestation in both regions, which in Spain was caused by a significant decrease in N concentration. No consistent effect was found on mineralisation rates due to vegetation change. Afforestation produced a more consistent soil 13C enrichment in the Spanish than in the Austrian sites. Our work strongly suggests that increasing altitude in Mediterranean mountain grasslands alleviates water limitation, favouring both plant growth and SOM decomposition, and ultimately accelerating C cycling. In contrast, temperate grassland areas at high altitudes were associated with severe temperature limitations, which constrained SOM transformation processes. In spite of the impact of afforestation on soil biogeochem- ical processes, C concentrations were marginally affected. We therefore conclude that grassland conver- sion to coniferous forests does not enhanced C seques- trationin themineral soil, for at least 40 years after land- use change. | |
Internacional
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Si |
JCR del ISI
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Si |
Título de la revista
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Biogeochemistry |
ISSN
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0168-2563 |
Factor de impacto JCR
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3,407 |
Información de impacto
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Datos JCR del año 2015 |
Volumen
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131 |
DOI
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10.1007/s10533-016-0278-5 |
Número de revista
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Desde la página
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267 |
Hasta la página
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280 |
Mes
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SIN MES |
Ranking
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