Landscape composition outperforms configuration in explaining bee communities across different habitats in France

Understanding how landscape composition or configuration shapes bee communities in different habitats is essential for designing landscape management that supports pollinator communities. We evaluated whether the local diversity of bee communities across different habitats is explained by landscape composition or configuration metrics. We also assessed the effect of landscape attributes and local environmental variables (temperature, wind, precipitation, and altitude) on bee species turnover along the coastal-to-inland gradient in southwestern France. Bees were sampled in 75 sampling sites in southwest France, covering eight natural and semi-natural habitat types (spruce plantations, peatlands, tall-herb meadows, calcareous grasslands, grey dunes, dry heaths, wet heaths, and prairies). Landscape variables included compositional (percentage of classes, compositional heterogeneity) and configurational (edge density, number of patches) metrics. We correlated bee community variables with landscape compositional and configurational attributes. Bee communities were explained by landscape composition attributes. Increasing landscape heterogeneity positively affected bee richness, abundance, and diversity (H’). The direction of the effect of the landscape heterogeneity on bee communities varied among habitat types. Moreover, the cover of coniferous forest, spatial distance, and altitude drove compositional changes in bee communities, increasing species turnover. Natural and semi-natural habitats in southwestern France were historically replaced by monoculture coniferous plantations for timber, resulting in landscape homogenization, reduced habitat heterogeneity, and limited floral and nesting resources. Our results highlight that promoting mosaics of natural and semi-natural habitats and enhancing compositional heterogeneity at the landscape scale are critical for sustaining bee communities in European agricultural landscapes.