Habitat type outweighs urban proximity in shaping cavity-nesting hymenopteran communities

Habitat type and land-use change are key drivers of biodiversity patterns, influencing species composition and ecological interactions in human-modified landscapes. We investigated the relative effects of habitat type, comparing forest fragments and organic crops, and urban proximity on cavity-nesting hymenopteran communities and their natural enemies. We recorded 846 nests and 2,366 individuals, comprising 12 host species, 16 natural enemy species, and 42 trophic interactions. Habitat type significantly influenced community structure, whereas urban proximity showed no consistent effect across response variables. Abundance was higher in crop habitats, but species richness did not differ between environments. Community composition differed markedly between habitats and was mainly driven by species turnover, indicating the presence of distinct species pools rather than nested subsets of the same community. Interaction dissimilarity was moderate and primarily explained by rewiring among shared species. Crop networks showed higher nestedness than expected under null models, whereas modularity was similar between habitats. These results indicate that local habitat characteristics are more consistent drivers of cavity-nesting hymenopteran communities than urban proximity, and that biodiversity responses in human-modified landscapes are better explained by species turnover and interaction reorganization than by species loss alone.