Higher Functional Diversity in Simplified Landscapes : Rethinking Bird Responses in (…)

ABSTRACT

Agricultural intensification has profoundly reshaped farming systems and eroded biodiversity. Yet, despite extensive research on these impacts and their restoration, the avifauna of viticultural agroecosystems on the southern Mediterranean shore remains understudied. From September 2022 to August 2023, we performed 742 point-count surveys in Moroccan vineyards, recording 4040 individuals across 38 species (64.1% residents, 35.9% insectivores). Using AICc-based model selection, we tested how landscape type and management system affect taxonomic diversity, functional diversity (FRic, FDis, FDiv, RaoQ), and guild-specific abundance. Our results suggest a hierarchical environmental filter governing community assembly: landscape type determines the baseline potential for functional diversity, while management system locally modulates its expression. In conventional vineyards, high edge density acts as a detrimental filter, rendering functional diversity dependent on spatial structure. Conversely, organic systems consistently supported null models, indicating a decoupling from landscape constraints. Organic management maintained functional diversity even in simplified landscapes, outperforming conventional systems in stability and resilience. This pattern suggests that organic farming buffers avian ecological functions against landscape fragmentation within viticultural systems. Ultimately, our findings identify key environmental drivers of bird diversity in understudied Mediterranean agroecosystems, highlighting the role of local agricultural practices in sustaining functional biodiversity.