Global and regional ecological boundaries drive abrupt changes in avian frugivory interactions

<jats:title>Abstract</jats:title><jats:p>Species interactions can propagate disturbances across space, though ecological and biogeographic boundaries may limit this spread. We tested whether large-scale ecological boundaries (ecoregions and biomes) and human disturbance gradients increase dissimilarity among ecological networks, while accounting for background spatial and elevational effects and differences in network sampling. We assessed network dissimilarity patterns over a broad spatial scale, using 196 quantitative avian frugivory networks (encompassing 1,496 plant and 1,003 bird species) distributed across 67 ecoregions and 11 biomes. Dissimilarity in species and interactions, but not in network structure, increased significantly across ecoregion and biome boundaries and along human disturbance gradients. Our findings suggest that ecological boundaries contribute to maintaining the world’s biodiversity of interactions and mitigating the propagation of disturbances at large spatial scales.</jats:p><jats:sec><jats:title>One-Sentence Summary</jats:title><jats:p>Ecoregions and biomes delineate the large-scale distribution of plant-frugivore interactions.</jats:p></jats:sec>