Neotropical Rivers as Potential Interaction Corridors: An Evaluation of Frugivory Metanetworks Across Two Biogeographic Domains in South America

Aim Frugivory interactions vary widely, yet their connectivity and spatial structuring at regional scales remain poorly understood. Using a metanetwork approach, we aim to test whether large rivers and their associated riparian habitats function as “interaction corridors” by linking otherwise segregated local networks. We studied avian frugivory in two contiguous Neotropical domains: the xerophytic Chaco and the humid Paraná, the latter embedded within a riverine corridor shaped by South America's second largest lowland river system. Location Santa Fe Province, Argentina. Taxon Avian frugivores and fleshy fruiting plants. Methods We recorded avian frugivory interactions across six forest sites spanning two neotropical Biogeographic domains. Then, we constructed aggregated and domain‐specific metanetworks to test whether sites are functionally connected through ecological interactions facilitated by riverine connectivity. We quantified (i) measures of connectance, nestedness, and modularity, (ii) interactions centrality and their correlated functional traits, and (iii) assessed beta diversity of species and interactions, which allowed us to evaluate patterns of turnover and nestedness across spatial and biogeographic gradients. Results The aggregated metanetwork revealed a connected core (Paraná) and a peripheral region (Chaco), characterised by high turnover of plants and interactions, moderate bird turnover and high plant nestedness. The chaco network exhibited higher modularity, lower connectance and nestedness, and greater beta diversity. In contrast, the Paraná network showed higher connectance and lower beta diversity, nestedness and modularity. Consistently, most interactions were peripheral and site‐specific, with only a small subset of interactions connecting sites. Trait analyses revealed differences in Interaction roles in Paraná but not in Chaco. Main Conclusions Our findings highlight the potential role of large rivers, and their associated riparian habitats, as functional corridors of species dispersal and interaction flows, influencing the spatial structuring of frugivory metacommunities at large scales. This has important implications for biodiversity conservation and the maintenance of ecosystem processes in Neotropical land and riverscapes.