Changes in biodiversity after abandonment in dehesa systems in the province of León.

The aim of this work was to determine the changes of diversity of plant community in relation to silvopastoral use. For this purpose seven zones with a different livestock pressure were compared, the cover of all understorey species was estimated and the diversity per quadrat (alpha diversity), the global diversity of each zone (gamma diversity) and the spatial heterogeneity (beta diversity) were compared. The pasture zones show great diversity on a small scale, but they are far more homogeneous (less beta diversity). The zones dominated by woody species show less alpha and gamma diversity, but greater heterogeneity. Finally greater gamma diversity was observed in the zones of intermediate grazing pressure.