Attempting to capture the full complexity of an urban pollination system

Native plants are an important component of urban greening efforts, but the quality of pollination services they receive and therefore their ability to reproduce via seed may impact their ability to compete against invasive species and persist in the face of anthropogenic disturbances. We investigated pollination services in the Chicago suburbs using a native sentinel species, Bidens aristosa, and sampled the bees and flowering plants in powerline corridors and residential backyards to understand the effects of land management on these communities. To sample floral resources, we conducted 3 visual surveys where we counted inflorescences and identified plants to species. To sample bees, we performed both timed visual observations and pan trap assays. We analyzed the complex relationships between land management, flowering plants, bees, and pollination services using a piecewise structural equation modeling approach that included both taxonomic and functional trait-based measures of the flowering plant and bee communities. Our results indicate that land management directly affects both the flowering plants and bees in the Chicago suburbs, but that the mechanisms directly affecting pollination of B. aristosa are less clear. Our study provides a novel approach to understanding urban pollination services and indicates that more work needs to be done to identify the most important environmental factors affecting urban pollination services.