Landscape anthropization drives composition and diversity of butterfly communities at a regional scale

Aim While landscape anthropization is a key driver of biodiversity change, its effects on communities are underexplored, especially at regional scales. In the Anthropocene, climate and habitat diversity alone are insufficient to explain community structure. However, until recently, ecologists lacked accessible, synthesized data describing anthropization gradients, which limited studies to macro-ecological scales. Yet, a deeper understanding of how anthropization shapes species pool and local communities is crucial for biodiversity conservation, especially in historically anthropized areas. Location France Time period 2010-2020 Major taxa studied Butterfly Methods Using a high-resolution (20 m) anthropization map describing anthropization on a continuous gradient across France, we examined the influence of landscape anthropization on taxonomic, functional, and phylogenetic diversities and composition of butterfly communities in Brittany (France). This taxon is known to be widely impacted by landscape changes and is an indicator of ecosystem health. We compiled 175,000 butterfly occurrences recorded from 2010 to 2020, spanning 2,447 communities across the anthropization gradient with multi-facet biodiversity indices. Results We showed that anthropization significantly shapes community structure, sometimes even exerting a stronger influence than habitat diversity or landscape heterogeneity. Relationships between anthropization and community diversity within the same biogeographical region were often linear rather than Gaussian, with diversity decreasing as anthropization increased. Highly anthropized sites hosted communities with lower habitat and dispersal specialization and lower species richness. Main conclusions These results highlight the importance of landscape matrix and typical habitats, rather than habitat quantity, in shaping biodiversity. Integrating local scale anthropization in public policies and conservation strategies is essential for effective ecological conservation and restoration.