Generalist species are important for maintaining network structure and function. Previous studies showed that interactions between generalists persist across sites and years. However, the mechanisms for persistence across spatiotemporal scales are not clear. To address this gap, we collected data on plant--pollinator interactions throughout the flowering period for five years across six plots in a subalpine meadow. We hypothesized that tolerance of environmental variation across time and space plays a key role in species' generalization by regulating spatiotemporal overlap with partners. We found that interactions between species with broader temporal and spatial distributions tended to be more generalized such that interactions near the network core were more persistent across years and plots and within seasons. These results further understanding of networks by linking the role of environmental variation in time and space in organizing interactions, marrying niche concepts that emphasize species environmental constraints and their role in the community.