Extensive livestock systems as tools for environmental management: impact of grazing on the vegetation of a protected mountain area.

Abstract

AbstractThe study was conducted in the 'Sierra de Guara' Natural Park (80 739 ha, Huesca, Spain), a protected area dominated by shrub and forest pastures. The effect of livestock grazing on herbaceous and shrub vegetation was determined in six locations representative of pasture types in the park. Vegetation characteristics were measured in adjacent grazed and non-grazed areas before and after the grazing season in three consecutive years. Sward height, biomass, green-dead ratio and chemical composition were analysed, and shrub vegetation was characterized in terms of species composition, volume and biomass. The evolution patterns in non-grazed and grazed areas were significantly different, with higher herbage biomass accumulation in the former, both in absolute terms (2609 vs 1070 kg DM/ha in the third year, P<0.001) and when only dead material was considered (1898 vs 499 kg DM/ha, P<0.001), and with lower forage quality. Results concerning shrub vegetation revealed a similar trend. These results underline the role that livestock can play in biomass control and reduction of landscape degradation, which has particular relevance in protected natural areas.