Data from: Attractiveness of exotic invasive plants can disconnect native plants from their floral visitors

Exotic invasive plant species (EIP) threaten ecosystem diversity and
stability through competition for abiotic resources with native plant
species. They can also compete for pollinators, as native floral visitors
can incorporate EIP floral resources (i.e., pollen and nectar) in their
diets, potentially shifting their foraging behaviour away from the native
flora. To decipher how EIP attract native floral visitors and the
potential competition between EIP and native plants for pollinators, we
focused on five major exotic invasive plant species in Europe: Buddleja
davidii, Impatiens glandulifera, Reynoutria japonica, Robinia pseudoacacia
and Senecio inaequidens. We recorded in 16 sites in Belgium: (i) EIP
floral visitors, (ii) EIP pollen carried by these visitors, and (iii)
pollen from native plant species on these visitors. We showed that bees
were the dominant visitors and pollen vectors for Impatiens glandulifera,
Robinia pseudoacacia, and Buddleja davidii; hoverflies were the primary
visitors for Senecio inaequidens; and non-hoverfly flies, alongside bees,
were the most frequent visitors for Reynoutria japonica. Senecio
inaequidens exhibited the highest species richness of floral visitors,
species richness of pollen vectors, and shared interactions with native
plant species. Impatiens glandulifera exhibited the highest pollen
transfer efficiency, with nearly 90% of its floral visitors carrying its
pollen. While floral visitors of the other four studied species also
interacted with numerous native plants, those of I. glandulifera carried
its pollen almost exclusively, potentially substituting native species.
These findings highlight how widely introduced exotic invasive plant
species can integrate native pollinator networks to the point of
disconnecting local pollinators from their original resources.