Are soil carbon stocks in mountain grasslands compromised by land-use changes?

Mountain grasslands are generally rich in soil organic C, but the typical high spatial variability of mountain environments, together with the different management systems, makes their soil C content particularly variable. Socio-economic changes of the past decades have caused a progressive abandonm...

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Detalles Bibliográficos
Autores: Garcia-Pausas, Jordi, Romanyà i Socoró, Joan, Montané, Francesc, Rios, Ana I., Taull, Marc, Rovira, Pere, Casals, Pere
Tipo de recurso: capítulo de libro
Estado:Versión publicada
Fecha de publicación:2017
País:España
Institución:Universitat de Lleida (UdL)
Repositorio:Repositori Obert UdL
OAI Identifier:oai:repositori.udl.cat:10459.1/69235
Acceso en línea:https://doi.org/10.1007/978-3-319-55982-7_9
http://hdl.handle.net/10459.1/69235
Access Level:acceso abierto
Palabra clave:Grassland abandonment
Land-use changes
Mountain grasslands
Grazing intensification
Shrub encroachment
Soil organic carbon
Descripción
Sumario:Mountain grasslands are generally rich in soil organic C, but the typical high spatial variability of mountain environments, together with the different management systems, makes their soil C content particularly variable. Socio-economic changes of the past decades have caused a progressive abandonment of the traditional use for grazing of some areas, while grazing pressure at easily accessible grasslands have increased. Here, we analyse the effect of these land-use changes on the factors regulating the soil C accumulation and stocks. Overgrazing generally leads to a reduction above- and below-ground litter inputs and a decrease in soil C stocks, affecting some soil physicochemical and biological properties. Additionally, the labile C inputs coming from animal faeces may accelerate the mineralisation of organic matter. Grazing abandonment causes a reduction of aboveground productivity, but the lack of consumption causes a short-term accumulation of organic matter. Its effect on belowground biomass and productivity is less clear. At longer term, grazing abandonment causes a change in the plant community composition, having the shrub encroachment the strongest effect on C storage. The low biochemical quality of shrub litter delays its decomposition and allows higher organic matter accumulation in the topsoil. But the effect of shrub proliferation at the deeper soil is less clear. The low root turnover of shrubs compared to grasses may reduce the C inputs to the soil. But, at the same time, the reduction of the root exudates may also reduce the microbial activity and the organic matter mineralisation.