Using beta diversity to inform agricultural policies and conservation actions on Mediterranean farmland

1. Spatial variation in species composition (β-diversity) is an important component of farmland biodiversity, which together with local richness (α-diversity) drives the number of species in a region (γ-diversity). However, β-diversity is seldom used to inform conservation, due to limited understanding of its responses to agricultural management, and lack of clear links between β-diversity changes and conservation outcomes.
2. We explored the value of β-diversity to guide conservation on farmland, by quantifying the contribution of bird α- and β-diversity to γ-diversity variation in low- and high-intensity Mediterranean farmland, before (1995-1997) and after (2010-2012) the Common Agricultural Policy reform of 2003. We further related β-diversity to landscape heterogeneity, and assessed the conservation significance of β-diversity changes.
3. In 1995-1997, bird diversity was highest in low-intensity farmland, where it further increased in 2010-2012 due to a strong positive contributio...