Management, topography and landscape contribute to shape bird communities in Alpine semi-natural grasslands

Grasslands are key habitats for biodiversity in Europe but are declining and degrading due to abandonment, conversion and intensification. Many grassland specialist species have declined; some have found refuges from intensification in mountain grasslands but are now threatened there by land use and climate changes. We assessed the link between grassland breeding bird communities (species richness and abundance of functional groups), and landscape/topography/management in 166 transects in the Italian Alps, along environmental and management gradients, using multi-model inference. All types of predictors contributed to shaping all traits of avian communities (112 species), but with varying importance. The most relevant management variable was (intensive) valley floor grasslands, influencing negatively insectivores, and positively granivorous and pest species. Among subsidies related to the Common Agricultural Policy, only late mowing (10.1.1) and organic management entered few models with positive effects. Landscape features were the most frequent predictors. Broadleaved forests influenced positively vegetation-dwelling insectivores, and negatively the number of grassland species and both ground-dwelling insectivores and granivorous species. Apple orchards negatively impacted on species richness and insectivores. Alpine grasslands affected positively grassland species, and negatively other community metrics. Finally, the number of grassland species and grassland-dwelling insectivores increased with elevation, contrary to most of other species. Future policies should revise subsidies to implement a more biodiversity-oriented management, together with the preservation of low-intensity grasslands. Preserving ecologically functional grassland only at high elevation is not enough to conserve biodiversity and related ecosystem services, due to the linkage with low elevation of many functional groups and species.