Heterogeneous orchard configurations support abundant breeding bird populations and diverse communities in intensive apple orchards

Agricultural intensification often threatens biodiversity and jeopardises the ecosystem functions that underpin current and future food production. Modern agriculture must thus reconcile production with biodiversity. In fruit orchards, intensification implies heavy structural and landscape simplification, mechanised management and increased chemical inputs. Here, we investigated the factors influencing orchard-dwelling bird populations in intensive apple orchards of northern Italy. We carried out a two-level analysis, focusing on the abundances of ten common orchard-nesting species and on the richness/diversity of the whole orchard-dwelling avian community, and combined them into a meta-regression framework. Intensive apple orchards hosted a simplified community, dominated by generalist woodland species (mainly Turdidae and Fringillidae). Under the most intensified conditions (i.e. higher orchard cover and denser trees), the abundance of common orchard-nesting species increased, while community metrics decreased. Landscape heterogeneity had positive effects on community metrics, but not on the abundance of common orchard-nesting species. Notably, spatial heterogeneity in the age of orchard parcels simoultaneously promoted both higher species abundances and more diverse avian communities. This heterogeneity in orchard configuration may provide a win-win solution for crop renewal, bird conservation and the potential delivery of bird-mediated ecosystem services (namely, pest and weed control, and recreation). We therefore suggest that future renewals of apple orchards programmatically enhance age heterogeneity, e.g. by retaining older parcels within renewed orchards. Promoting heterogeneous configurations would contribute to a more sustainable apple production, conserving orchard-dwelling declining species and enhancing the potential delivery of ecosystem services.