Abstract
Urban systems, particularly botanical gardens, often comprise a lot of exotic plant species that can integrate into local plant-pollinator networks, influencing their temporal structural dynamics. However, revealing how plant-pollinator interactions are continuously reshaped and how the roles of native plant and exotic plant species within networks alter over time remains a significant challenge. Here, we reconstructed monthly plant-pollinator interaction networks for 12 months within an urban botanical garden. We focused on the monthly variations in the structure of pollination networks and the roles of native and exotic plant species. The results showed that the dynamics of plant-pollinator interactions are characterized by significant changes in network structure and species alternations, which have substantial impacts on community processes. Each month, the plant-pollinator network can be divided into several modules of closely interacting plants and pollinators, and these modules form complex fission-fusion dynamics across the year. Monthly dynamic changes in plant-pollinator network structure led to alternations of plant species occupying core positions within the networks. The core plant species in the pollination networks alternated between native and exotic species across the 12 months, suggesting that plant species can be core species independently of their origin in urban plant-pollinator networks. Therefore, the roles of native and exotic plant species in plant-pollinator networks can only be fully detected and understood from the perspective of time-scale dynamics. These results suggest that information on the dynamic changes in plant-pollinator network structure is critical for understanding the temporally varying role of core species in urban ecosystems.