Response of wild bee assemblages and floral resources to management of restored wetlands in central New York

To effectively protect wild bee pollinators and the services they provide, it is critical to understand habitat use patterns across a diversity of cover types. Wetlands are underrepresented in bee surveys, and although wetland restoration produces conservation benefits for birds, how hydrological management influences bee assemblages and availability of floral resources is still poorly known. In this study, actively (full or partial water drawdowns) and passively managed restored wetlands in central New York were surveyed to characterize plant and bee assemblages, June–September 2019 and 2020. Over 9,000 bees were collected using pan traps and sweep netting, representing ≥ 109 species in 25 genera. Environmental variables, e.g., percent open water and mudflat frequency, differed among management treatments, and were better predictors of entomophilous plant species composition, bee richness, and/or entomophilous plant richness and occurrence than management treatment alone. Entomophilous plant occurrence varied negatively with invasive graminoid occurrence. Although bee assemblage composition was best explained by phenological turnover, diverse moist-soil flowers in late summer and long-blooming emergent flowers were important to generalists and specialist bees. Emergent wetlands offered valuable floral resources for wild bees, making wetland restoration and management a useful pollinator conservation approach. Maintaining a complex of wetlands by cycling through different hydrological conditions, and controlling densities of invasive plants, can diversify and increase resources available for bees, while also meeting management goals for wetland wildlife.