Pasture management under goat grazing on Canary Islands

Tenerife pastures in the Teno plateau are under a goat grazing management system, and the number of goats has increased by 70% in the past 10 years. This plant community was sampled during 4 years (1992, 1993, 1994 and 1999) over a 10-year period, using ten 0.25 m2 plots to reveal changes in species composition, soil nutrient content, and biomass nutrient content over time and relate these variables to changes in management and understand aspects of the dynamics of these pastures. The results revealed no changes in biomass nutrient composition over the sampling period; however, biomass protein content was related to changes in species composition. Soil phosphorus content increased in the last sampling year and was related to an average species richness decrease in the plots. Results suggest that the increase in soil phosphorus and the decrease in species richness are related to the increase in goat grazing intensity. At the end of the studied period, species with a higher protein content increased in importance in the species composition. The restoration of pastures degraded by agriculture or overgrazing is required to provide a larger area for grazing and to ensure sustainable management of these protected areas.