Thesis defense of Vincent ZANINOTTO

” Ecology and functioning of plant-pollinator communities in a dense urban environment: the city of Paris throughout the seasons”

Urbanization is one of the main causes of biodiversity loss. Organisms in the city, in particular insect pollinators, are subject to multiple constraints. In this thesis, I characterized pollinator communities and their seasonal dynamics in a dense urban landscape, the city of Paris, through empirical and standardized approaches.

I studied the specificities of these urban communities, focusing on taxonomic and functional diversity. Then, I investigated the foraging activity patterns and the dynamics of plant-pollinator interactions throughout the seasons.

Despite its high density, Paris is home to relatively rich and abundant pollinator communities, which can provide efficient pollination of some plants. However, these communities are constrained by the urban environment, and undergo functional filtering. Moreover, in the city, natural seasonal dynamics are weakened in terms of pollinator activity. Flower resources play a key role in maintaining pollinator diversity, particularly through native and spontaneous flora. I provide design and management guidelines for green spaces, in order to promote biodiversity and pollination in cities.

Key-word: urban ecology ; pollination ; phenology ; plant-pollinator networks ; urban heat island ; greenspace management