Plant–Bee Interaction Network in an Atlantic Forest Fragment of a Neotropical Metropolis

Urbanization is a major driver of biodiversity loss and profoundly alters the structure of species interaction networks. Nevertheless, urban forest remnants may still sustain structurally and functionally diverse pollinator networks. Here, we characterize the structural and functional organization of a plant-bee interaction network within a large Atlantic Forest fragment embedded in a tropical metropolis in northeastern Brazil. We quantified 4,700 plant-bee interactions involving 19 plant and 80 bee species and evaluated network connectance, nestedness, modularity, specialization, and species- level functional roles. The network was relatively sparse, exhibited low nestedness, moderate modularity, and high specialization. Most plant and bee species occupied peripheral positions, whereas a small subset of abundant eusocial stingless bees, particularly Trigona spinipes (Fabricius) and Scaptotrigona tubiba (Smith), functioned as connectors linking interaction modules. No species acted as a true network hub, indicating limited integration among modules. Together, these patterns reveal a network dominated by a few generalists and many low-degree species, consistent with functional filtering in urban landscapes. Despite this, the remnant supported ecologically important interactions involving both generalist and specialized pollinator guilds. Our findings highlight the ecological value of large, heterogeneous urban forest patches, such as Pituaçu Metropolitan Park, and their role in maintaining pollination network structure and function, with important implications for the planning and conservation of urban green areas in tropical cities.