title: The proportion of impervious surfaces at the landscape scale structures wild bee assemblages in a densely populated region.
abstract: Given the predicted expansion of cities throughout the world, understanding the effect of urbanization on bee fauna is a major issue for the conservation of bees. The aim of this study was to understand how urbanization affects wild bee assemblages along a gradient of impervious surfaces and to determine the influence of landscape composition and floral resource availability on these assemblages. We chose 12 sites with a proportion of impervious surfaces (soil covered by parking, roads, and buildings) ranging from 0.06% to 64.31% within a 500 m radius. We collected using pan trapping and estimated the landscape composition of the sites within a 500 m radius and the species richness of plant assemblages within a 200 m radius. We collected 1104 bees from 74 species. The proportion of impervious surfaces at the landscape scale had a negative effect on wild bee abundance and species richness, whereas local flower composition had no effect. Ground-nesting bees were particularly sensitive to the urbanization gradient. This study provides new evidences of the impact of urbanization on bee assemblages and the proportion of impervious surfaces at the landscape scale emerged as a key factor that drives those assemblages.
authors: CNRS, IRD Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale (IMBE) Aix Marseille Université Avignon Université Pôle St Jérôme av. Escadrille N. Niemen 13397 Marseille Cedex 20 France; CNRS, UMR 7618 iEES-Paris F-75005 Paris France.
authors: Benoît
authors: B
authors: Geslin
authors: INRA, UMR 406 Abeilles et Environnement INRA Site Agroparc F-84914 Avignon Cedex 9 France.
authors: Violette
authors: V
authors: Le Féon
authors: CNRS, UMR 7618 iEES-Paris F-75005 Paris France.
authors: Morgane
authors: M
authors: Folschweiller
authors: CNRS, UMR 7618 iEES-Paris F-75005 Paris France; Université Paris Diderot-7 F-75013 Paris France.
authors: Floriane
authors: F
authors: Flacher
authors: CNRS, UMR 7618 iEES-Paris F-75005 Paris France.
authors: David
authors: D
authors: Carmignac
authors: CNRS, UMR 7618 iEES-Paris F-75005 Paris France; Université Pierre et Marie Curie-6 F-75005 Paris France.
authors: Eric
authors: E
authors: Motard
authors: CEREEP Ecotron ÎleDeFrance UMS CNRS 3194 Saint-Pierre-lès-Nemours France.
authors: Samuel
authors: S
authors: Perret
authors: CNRS, UMR 7618 iEES-Paris F-75005 Paris France; Université Pierre et Marie Curie-6 F-75005 Paris France.
authors: Isabelle
authors: I
authors: Dajoz
keywords: Bees; community ecology; gradient; landscape scale; urbanization