Colonization and extinction dynamics among the plant species at tree bases in Paris (France)

1. In cities, trees growing along streets could play an important ecological role for spontaneous plants that grow at their bases. For example, these trees could represent corridors that allow species to move in the urban matrix by potentially connecting large green spaces (e.g., parks, gardens, etc.) We considered sets of urban trees in 15 streets as metapopulations for 15 plant species. Our objective was to determine the factors influencing the dynamics of colonization and extinction of populations based on the distance of the streets from green spaces and the biological traits of each species. 2. The species in 1,324 tree bases of the Bercy district of Paris were surveyed annually from 2009 to 2015. For each species and each street, we used SPOMSIM software to identify the best-fit metapopulation model: the propagule rain model (PRM), Levins model (LM), and the PRM and LM with a fixed extinction or a rescue effect. 3. The results demonstrated that the species more often conformed to ...