Wild bees are key witnesses of landscape transformations. Despite a prolific literature on bee conservation, the impact of urbanization on their communities remains unclear, with highly context-dependent results. This limited understanding is aggravated by the fact that few studies have formally examined the impact of diversity indices on their analyses. We addressed this gap by analyzing more than 6,000 specimens across 91 sites, including protected areas, within a highly anthropized landscape. We found that urbanization increased abundance-based diversity indices while simultaneously reducing the richness of threatened species, which only benefited from flower-rich grasslands. This discovery could clarify conflicting results of previous studies, revealing that the decline of threatened species in urban areas may be overshadowed by diverse communities of abundant species. Moreover, we reveal that the existing network of protected areas may not be able to mitigate this decline, as most reserves were dominated by unsuitable forested environments.

Commercial apple production relies on managed honey bees for pollination, and on intensive management for pest control. Previous studies revealed the detrimental effects of these factors on wild bee diversity in agroecosystems, and the pollination services they provide. However, the extent to which honey bee dominance and management interact under field-realistic conditions to shape wild communities has never been investigated. We measured the species richness and functional and phylogenetic diversity of wild bees associated with apple blossoms, in 46 organic and non-organic orchards, and along a climatic gradient across Western Europe and Morocco. Our results consistently show a strong and negative association between honey bee dominance and all diversity indices, regardless of local practices and surrounding landscape cover. Collectively, we show that wild bee diversity decreases with increasing honey bee density, with alternative management practices (i.e., organic) having no significant influence on wild bee communities in commercial apple orchards.