Non‐Native Plants Alter Bird‐Plant Frugivory Network Structure in a Human‐Modified Tropical Landscape

Abstract

Frugivory interactions are key plant–animal mutualisms that facilitate seed dispersal and promote ecosystem resilience. However, these interaction networks are increasingly altered by the widespread introduction of non-native plants through human activities. The integration of such species into frugivory networks—and their consequences for network stability—remains poorly understood. Here, we examined the role of non-native plants in shaping frugivory network structure and robustness in a human-modified tropical landscape. Using DNA metabarcoding of faecal samples from 21 frugivorous bird species in Gamboa, Panama, we identified consumed plant species and quantified the contribution of non-natives to avian diets. Non-native plants significantly altered network structure, reducing nestedness while increasing connectance and modularity compared to native-only networks. Extinction simulations revealed that non-native plants, despite comprising only 28% of plant species, triggered disproportionately higher secondary bird extinctions. Yet, these species showed lower persistence during sequential bird removals, creating a paradox: they act as crucial connectors within the network while simultaneously undermining its stability. Notably, three non-native species served as key connector species linking network modules. The high connectivity of certain non-native connector species is particularly concerning given their documented invasive potential in other regions. We anticipate that these findings will inform conservation strategies in human-modified landscapes, particularly regarding the monitoring and management of highly connected non-native plants that may both compromise ecosystem stability and facilitate biological invasions. While non-native plants may provide temporary alternative food resources for adaptable frugivorous birds navigating increasingly human-modified environments, they simultaneously risk diverting seed dispersers from native plants and undermining long-term ecosystem integrity.