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

Abstract

In cities, trees planted along streets could play an important ecological role for spontaneous plants growing at their bases. For example, these trees could represent corridors by potentially connecting large green spaces (e.g., parks, gardens), which allow species to move within the urban matrix. We considered sets of urban trees in 15 streets in Paris, France, 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 to green spaces and biological traits of each species. Plant 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 between four models with different colonization and extinction functions: propagule rain model (PRM) and Levins’ model with or without rescue effect. Results demonstrated that species more often conformed to the PRM in streets near green spaces, which suggested that green spaces could act as sources for the populations in those streets. Species with seeds with long‐term persistence more often conformed to the PRM, indicating that a soil seed bank helps species invade entire streets. Finally, a higher percentage of species with a short height conformed to models with a rescue effect, which indicated that those small species resisted the effects of weeding by the city technical services better than taller species. Synthesis and applications. This study showed how biological traits of species and geography of the district determine the dynamics of plants in the streets, and these results may provide important information for biodiversity management in cities.

Broadening applications of stochastic patch occupancy models over three decades

“…The increase in class‐level diversity over the decades broadens the prospects of applying SPOMS to a wider diversity of organisms. We found studies for species where metapopulation processes are hard to identify, such as long‐lived species (e.g., Juniperus spp., Pinus spp., Alados et al., 2009; Asimina obovata , Opuntia humifusa , Quintana‐Ascencio & Menges, 1996), species with dormant stages (e.g., Chenopodium album , Omar et al., 2019) or species living in apparently continuous habitats ( Litoria raniformis , Heard et al., 2012; Clinostomus elongatus , Poos & Jackson, 2012). The prevalent application of the less complex models, especially the IFM, throughout the decades together with the considerable presence of the species‐ or landscape‐specific models, suggests that the increase in taxonomic diversity is a combined result of the dissemination of simple models to other taxonomic groups and the evolution of more nuanced model structures that make more acceptable assumptions.…”

Rescue effect drives local persistence of fish species in the Upper Paraná River floodplain

“…These findings are highly supportive of the rescue effect (Gotelli, 1991; Hanski, 1982), where immigration of individuals from surrounding populations decreases the extinction probability of a local population (Brown & Kodric‐Brown, 1977; Gotelli & Kelley, 1993; Schmidt & Beissinger, 2020). Although supported by theoretical models (Freckleton et al., 2005; Hanski, 1982), empirical evidence for the rescue effect decreasing regional and local extinction probabilities are somewhat divergent: while some early metapopulation studies have not found a strong correlation between the fraction of sites occupied and extinction probabilities (Gotelli & Kelley, 1993; Gotelli & Taylor, 1999b; Pfister, 1998), others have suggested that there is an effect (Dornier & Cheptou, 2012; Sutherland, Elston & Lambin, 2012; Bergerot et al., 2013; Vergara et al., 2016; Omar et al., 2019). For example, Taylor et al.…”

Detecting seed bank influence on plant metapopulation dynamics

“…We then tested whether the estimated SBCE probability was affected by the nature of the closest green space (see Omar et al., 2019), the seed dispersal mechanism, the flowering months (extracted from the database of the collaborative network of French botanists ‘Tela botanica’, http://www.tela-botanica.org), the releasing height of the seeds and the seed weight (mean value obtained from the LEDA database, Kleyer et al., 2008). We used a mixed‐effect linear regression model with SBCE probability as response variable, in which we integrated a weighting vector to take into account the degree of confidence on the estimated SBCE probability.…”

“…Indeed, the population of plants in urban tree bases is located inside an inhospitable matrix and has a high turnover, which makes metapopulation models particularly suited (Dornier et al., 2011). Studies using presence/absence data for various species present in urban tree bases considered as metapopulations were already carried out, but to our knowledge none accounted for seed bank potential presence in tree bases (Dornier et al., 2011; Omar et al., 2019). We also attempted to relate the SBCE probability to species traits and environmental characteristics.…”