Livestock Grazing Impacts on Herbage and Shrub Dynamics in a Mediterranean Natural Park

Authors
Riedel, José Luis Francisco; Bernues, Alberto; Casasus, Isabel
Publication Year
2013
Language
English
Format
article
Status
Published version
Description
Shrub encroachment can be explained by the abandonment of extensive livestock farming and changes to land use, and it is a common problem in the Mediterranean mountain pastures of Europe, with direct effects on biodiversity and landscape quality. In this paper, the effects of livestock exclusion vs. grazing on the dynamics of shrub and herbaceous vegetation were analyzed in a Spanish natural park located in a dry Mediterranean mountain area over a 5-yr period. Twelve 10 × 10 m exclosures were set up in six representative pasture areas of the park (with two replicates per location). Each year, the shrub number, volume, and biomass were measured in April, and the herbage height, biomass, and quality were measured in April and December (which represent the start and end of the vegetative growth season). A sustained increase of the shrub population and individual biomass was observed throughout the study, which was reflected in total shrub biomass per ha. Growth was greater in nongrazed exclosures (2 563 kg dry matter [DM] · ha−1 · yr−1), but it also happened in the grazed control areas (1 173 kg DM · ha−1 · yr−1), with different patterns depending on the location and shrub species. Herbage biomass did not change when grazing was maintained, but it did increase in places where grazing was excluded (291 kg DM · ha−1 · yr−1), mostly as a consequence of the accumulation of dead material, with a concomitant reduction in herbage quality. It was concluded that at the current stocking rates and management regimes, grazing alone is not enough to prevent the intense dynamics of shrub encroachment, and further reductions in grazing pressure should be avoided.
EEA San Luis
Fil: Riedel, José Luis Francisco. INTA. Estación Experimental Agropecuaria San Luis; Argentina
Fil: Bernues, Alberto. Gobierno de Aragón. Centro de Investigación y Tecnología Agroalimentaria; España
Fil: Casasus, Isabel. Gobierno de Aragón. Centro de Investigación y Tecnología Agroalimentaria; España
Source
Rangeland Ecology & Management 66 (2) : 224-233 (March 2013)
Subject
Arbustos
Ganado
Pastoreo
Sistemas Agrosilvopascícolas
Cultivos de Pasto
Shrubs
Livestock
Grazing
Agrosilvopastoral Systems
Herbage Crops
Access level
Restricted access
License
Repository
INTA Digital (INTA)
Institution
Instituto Nacional de Tecnología Agropecuaria
OAI Identifier
oai:localhost:20.500.12123/3140