Disentangling direct and indirect drivers of farmland biodiversity at landscape scale

To stop the ongoing decline of farmland biodiversity there are increasing
claims for a paradigm shift in agriculture, namely from conserving and
restoring farmland biodiversity at field scale (α-diversity) to doing it
at landscape scale (γ-diversity). However, knowledge on factors driving
farmland γ-diversity is currently limited. Here, we quantified farmland
γ-diversity in 123 landscapes and analysed direct and indirect effects of
abiotic and land-use factors shaping it using structural equation models.
The direction and strength of effects of factors shaping γ-diversity were
only partially consistent with what is known about factors shaping
α-diversity, and indirect effects were often stronger than direct effects
or even opposite. Thus, relationships between factors shaping α-diversity
cannot simply be up-scaled to γ-diversity, and also indirect effects
should no longer be neglected. Finally, we show that local mitigation
measures benefit farmland γ-diversity at landscape scale and are therefore
a useful tool for designing biodiversity-friendly landscapes.