Temporal variation in the roles of exotic and native plant species in plant–pollinator networks

Abstract

AbstractThe role of individual plant species, including those that are rare or invasive, in the structure of plant–pollinator networks will depend on how connected the plants are to pollinator species and when they flower. Plant species visited by a high diversity of pollinators that visit few other species during a particular time period are thought to provide high value to the insect community. Here, we examined the role of plant species in a plant–pollinator network across the entire flowering season and across dune and adjacent woodland habitats in Wisconsin, USA. We found strong turnover of plants, pollinators, and their interactions in time and space. Both native and exotic species play important structural roles in plant–pollinator networks. Simulations reveal that the loss of the early‐flowering rare plant, Cirsium pitcheri, would result in a disproportionate loss of pollinator species. Furthermore, the critical role that this species plays in the network is not replaced by its exotic relative, Centaurea stoebe. Our research demonstrates that consideration of temporal and spatial variability in networks allows for critical plant species to be identified within a plant–pollinator network that might otherwise be overlooked.