Animal pollination is a critical ecosystem service required by over 90% of flowering plants. Like other interspecies interactions, this service is being disrupted by the introduction of invasive alien species. Recent studies have mostly focused on single species of plants or pollinators, however, less is known about how alien plants integrate successfully into a native plant-pollinator network through time. Using a historic plant-pollinator network documented by entomologist Charles Robertson in the late 1800’s as a reference, we re-sampled the network and compared the linkage density (average number of links per species) of old (alien plants present in Robertson’s time) and new (alien plants that invaded since the 1880’s) aliens to determine whether species with longer invasion histories established more links to pollinators. To further explore possible traits involved in the integration of alien plants, we incorporated native family size and breeding system into our analyses.

Results/Conclusions

We found that all alien plants studied had similar numbers of links to pollinators, and that breeding system did not affect the number of links established to pollinators by old versus new alien plants. However, the size of the native family was a significant predictor of links to pollinators, with alien plants in the largest native families receiving visits from the highest number of pollinator species. This suggests that alien species, regardless of their invasion history and breeding system, are integrated readily into the native pollination interaction network. The more important determinant of success in establishing links to the native pollinator community is the number of native species already present in the family of the invading alien plant species.