Avian Frugivore–Plant Interaction Networks of Barro Colorado Island

Birds disperse the seeds of up to three-quarters of tropical tree species, so avian frugivory and seed dispersal are key to determining the future distribution of adult plants and hence maintaining a range of ecosystem services. We collated previously published avian frugivore–plant interaction networks for Barro Colorado Island (BCI), encompassing 299 interactions between 59 bird and 86 plant species. The effects of geographical isolation on BCI’s network structure has probably been relatively minor, with ongoing movements of larger frugivores between BCI and the mainland, and relatively few extirpations of avian frugivores. However, climate change threatens all avian frugivore–plant interaction networks and, in the wider region, networks outside protected areas are vulnerable to habitat disturbance. The loss of large-gaped frugivores in human-modified landscapes likely leads to altered seed dispersal patterns. Only a fraction of the BCI network has been quantified; we have yet to identify the key dispersers for many plant species nor which plants are critical for maintaining avian frugivore populations on the island.