Trophic and Environmental Generalists Maintain Pollinator Network Functional Continuity by Switching Modules Through Time.

Plant-pollinator networks are temporally dynamic and crucial for ecosystem functioning. Yet, the characteristics of species that allow networks to persist through a season remain poorly understood. We investigated plant-pollinator interactions through an entire flowering season at four alpine meadows in SW China with a temporal multilayer network approach, where subnetworks representing successive time periods (layers) are interconnected via interlayer links. We show that temporal multilayer networks were highly modular, and that pollinator species' importance (versatility) in persistence through time of the multilayer network was correlated with their trophic and environmental niche space. Highly versatile pollinators persisted through time by switching between and occupying up to six network modules through time. These species with high versatility also had broad environmental and trophic niches, allowing them to maintain network functional stability throughout the flowering season. Future studies should investigate whether changes in plant-pollinator associations arise from active foraging decisions, such as switching among plant species to maximize resource acquisition or maintaining fidelity to preferred partners, or instead from environmentally and phenologically driven changes in plant availability and composition through seasons.