Multi-scale assessment of pollination of Lotus corniculatus (L.) in a peri-urban fringe

Abstract

Background: The plant pollination service provided by pollinators is crucial for ecosystem maintenance, especially in highly fragmented landscapes, such as urban areas. Aims: We assessed at multiple spatial scales the influence of the degree of urbanisation on pollinator communities and pollination success. Methods: Artificial populations of Lotus corniculatus (Fabaceae) were established along an urbanisation gradient in gardens where pollinator communities were surveyed. We described the plant and pollinator composition of gardens (local scale) and measured landscape structure in nested buffers (small and large landscape scales). Results: At the local scale, species richness and abundance of pollinators increased with the number of spontaneous plants and the size of semi-natural areas, while at the large landscape scale pollinators were more diverse and abundant in diversified landscapes with extensive green space and low cover of impervious surfaces. At the small landscape scale, the pollination success was favoured by agricultural areas, and disfavoured by housing density and fragmentation. It was also favoured by green space cover at the large landscape scale. Conclusions: The variables that affect pollination differ across spatial scales. Local and landscape variables have different effects according to spatial scale, suggesting different underlying causes, such as the presence of flower resources or of suitable habitats in the surroundings. Our results emphasise the importance of accounting for all spatial scales when managing pollination services.