Abstract

Urbanisation is increasing worldwide, with major impacts on biodiversity, species interactions and ecosystem functioning. Pollination is an ecosystem function vital for terrestrial ecosystems and food security, however, the processes underlying the patterns of pollinator diversity and the ecosystem services they provide in cities have seldom been quantified. Here, we present a comprehensive meta-analysis, using 133 studies, on the effects of urbanisation on pollinator diversity and pollination. Our results confirm the widespread negative effects of urbanisation on pollinator diversity, particularly of Lepidoptera. Additionally, pollinator responses were found to be trait-specific, with below ground nesting, solitary, and spring flyers more severely affected from urbanisation. Meanwhile, cities promote a greater diversity of non-native pollinators, which may exacerbate conservation risks to native ones. Surprisingly, despite the negative effects of urbanisation on pollinator diversity, pollination services in cities are enhanced and mediated by the high flower visitation rates of abundant generalists and managed pollinators. We highlight that the richness of local flowering plants could mitigate the negative effects of urbanisation on pollinator diversity. Overall, the results demonstrate the varying magnitudes of multiple moderators on urban pollinators and pollination service provision and could help guide conservation actions for biodiversity and ecosystem function for a sustainable future.