Natasha De Manincor

Abstract Wild bees and hoverflies are key pollinators, but their populations are declining in Europe. As the monitoring of each species would be arduous to implement, a cost-effective solution could be a shift from species level monitoring to an evaluation of the trends of functional groups. However, the lack of centralized trait databases hampers progress, as data are often dispersed across literature, limited to some countries or remain as expert knowledge.

1 Introduction Climate change is affecting species and their interactions in ecosystems across the world (Cruz et al. 2023; McCarty 2001; Pincebourde et al. 2017; Trunschke et al. 2024; Tylianakis et al. 2008). The linked population dynamics of some mutualists, such as flowering plants and pollinators, may make them especially vulnerable to population declines if their interactions are disrupted (Kiers et al. 2010; Kudo et al. 2025; Montes-Perez et al. 2025; Rafferty et al. 2015).

En 2014, 54 % de la population mondiale vivait en milieu urbain ; en 2050, ce nombre devrait atteindre plus de 60 %. Cette concentration humaine est strictement liée à une expansion des réseaux d’infrastructures et des surfaces urbanisées, au détriment des milieux naturels et des espèces qui y vivent.