Projected impacts of climate change on plant-frugivore interactions across the Americas

ABSTRACT Aim Frugivorous animals provide crucial seed-dispersal functions in terrestrial ecosystems. However, the potential effects of climate change on the interactions between plants and frugivores are largely unknown. In this study, we map plant-frugivore interactions across the Americas and then project potential changes in this interaction diversity under future scenarios of climate change. Location North, South and Central America. Time Period Present (1980–2010) and future (2070–2100). Major Taxa Studied Frugivorous birds and fruit-bearing plants. Methods Based on a trait-matching framework, we estimated interaction probabilities between frugivorous birds (n = 629 species) and fruit-bearing plants (n = 3283 species) to construct ecoregion-level plant-frugivore networks. To estimate future climate impacts, we compared the climatic niches of birds with ecoregion climates and weighted interaction probabilities based on the overlap between avian climatic niches and current and future ecoregion climates. Lastly, we used simulations to examine how avian dispersal and dietary flexibility may buffer the future diversity of plant-frugivore interactions. Results Under future climate scenarios, our models projected a decline in interaction diversity across most ecoregions, especially in tropical and subtropical ecoregions and biomes. In addition, simulations indicated that interaction rewiring through dispersal and dietary flexibility had the potential to mitigate future losses of interaction diversity, particularly in tropical forests. Main conclusions Our results suggest that plant-frugivore interactions are at risk of losing diversity under continued rapid climate change, which may undermine their stability and resilience. However, projected losses of interactions depend on the capacity of frugivorous bird species to modify their ranges or dietary preferences in future. As it is unknown to what extent these factors can buffer the stability of future interaction networks, the maintenance of high plant-frugivore interaction diversity in current networks is crucial to buffer ecosystems against future climatic changes, especially in the tropics.