Tropical plant-hummingbird interactions withstand short-term experimental removal of a common flowering plant

Theory suggests that species loss can trigger a coextinction cascade within a community, leading to declines in ecosystem function. However, experiments testing this prediction for plant-pollinator interactions remain uncommon. In this study, we simulated the local extinction of a hummingbird-pollinated understory plant, Heliconia tortuosa, from tropical forest fragments using a replicated before-after-control-impact (BACI) design while quantifying hummingbird abundance and space use (383 hummingbird captures and 36 radio-tagged individuals), flower visitation rates (> 19 000 observation hours), and pollination success (529 flowers). We expected that H. tortuosa removal would either result in 1) coextinction, in which hummingbirds vacate fragments and compromise the reproductive success of the remaining flowering plants, or 2) increased hummingbird reliance on alternative floral resources, leading to sustained fragment use (persistence). In our experiment, hummingbird behavior and plant-hummingbird interactions were remarkably resistant to loss of H. tortuosa, a locally common plant species representing at least 30-40% of the available nectar resources on average. However, we did not discover evidence that hummingbirds increasingly used alternative floral resources to cope with this temporary resource loss. With the important caution that short-term experiments may not emulate natural extinction processes, our study suggests that plant-pollinator interactions may be able to withstand single-species plant losses, but the exact mechanisms enabling hummingbird persistence after resource removal require further research.

Automated summary

This study used a simulated extinction of a hummingbird-pollinated plant to investigate the effects of species loss on plant-pollinator interactions. The results showed that hummingbird behavior and plant-pollinator interactions were resistant to the loss of the plant species, but further research is needed to understand how hummingbirds persist after resource removal.