Browsing by Subject "Environmental filtering"

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Floral visitation to alien plants is non‐linearly related to their phylogenetic and floral similarity to native plants
(2022) Razanajatovo, Mialy; Rakoto Joseph, Felana; Rajaonarivelo Andrianina, Princy; van Kleunen, Mark
Biological invasions are key to understanding ecological processes that determine the formation of novel interactions. Alien species can negatively impact floral visitation to native species, but native species may also facilitate early establishment of closely related alien species by providing a preadapted pollinator community. We tested whether floral visitation to alien species depended on phylogenetic relatedness and floral similarity to native species. In a field experiment, we simulated the early stages of an invasion by adding potted alien plants into co‐flowering native communities. We paired each alien plant with a host native plant, and recorded floral visitation to them for 3,068 hr (totalling 84,814 visits). We used 34 alien and 20 native species in 151 species combinations. We tested whether the number of floral visits to alien plants, the proportion of visits to alien plant relative to visits to both alien and native plants, and the similarity in flower visitor compositions of alien and native plants depended on phylogenetic and floral trait distances between alien and native species. Floral visitation to alien species was highest when they had intermediate floral trait distances to native species, and either low or high phylogenetic distances. Alien species received more similar flower‐visitor groups to natives when they had low phylogenetic and either low or high floral trait distances to native species. Co‐flowering native species may facilitate floral visitation to closely related alien species, and distantly related alien plants seem to avoid competition for flower visitors with native plants. Alien species with similar floral traits to natives compete with them for flower visitors, and alien species with dissimilar floral traits may not share flower visitors with native species. Alien species with intermediate floral trait distances to natives are most likely to receive flower visitors, as they are not too dissimilar and may still share flower visitors with native species, but not too similar to compete for flower visitors with them. The non‐linear patterns between floral visitation and similarity of the alien and native species suggest that an interplay of facilitation and competition simultaneously drives the formation of novel plant‐pollinator interactions.
Urbanization alters the spatiotemporal dynamics of plant–pollinator networks in a tropical megacity
(2023) Marcacci, Gabriel; Westphal, Catrin; Rao, Vikas S.; Kumar S., Shabarish; Tharini, K. B.; Belavadi, Vasuki V.; Nölke, Nils; Tscharntke, Teja; Grass, Ingo
Urbanization is a major driver of biodiversity change but how it interacts with spatial and temporal gradients to influence the dynamics of plant–pollinator networks is poorly understood, especially in tropical urbanization hotspots. Here, we analysed the drivers of environmental, spatial and temporal turnover of plant–pollinator interactions (interaction β-diversity) along an urbanization gradient in Bengaluru, a South Indian megacity. The compositional turnover of plant–pollinator interactions differed more between seasons and with local urbanization intensity than with spatial distance, suggesting that seasonality and environmental filtering were more important than dispersal limitation for explaining plant–pollinator interaction β-diversity. Furthermore, urbanization amplified the seasonal dynamics of plant–pollinator interactions, with stronger temporal turnover in urban compared to rural sites, driven by greater turnover of native non-crop plant species (not managed by people). Our study demonstrates that environmental, spatial and temporal gradients interact to shape the dynamics of plant–pollinator networks and urbanization can strongly amplify these dynamics.