Late season value of emergent wetlands for wild bees in the northeastern United States

To effectively protect native bee pollinators and the services they provide to ecosystems and agriculture, it is essential to understand their habitat and resource use patterns across a diversity of cover types. Wetlands are underrepresented in pollinator surveys, despite their known importance to certain oligolectic bees and countless wildlife. We conducted a two-year pollinator survey of a large restored wetland complex in central New York, collecting over 9,000 bees of ≥ 109 species. We documented 337 unique bee – plant interactions, with late- or long-blooming species such as Pontederia cordata (pickerelweed), Solidago gigantea (giant goldenrod), Persicaria hydropiperoides (swamp smartweed), and Bidens cernua (nodding bur-marigold) being of particular importance to bees. Floral resources and bee genera were most diverse in August, with the vast majority of oligoleges recorded in August and September, and a greater proportion of flowering plant species being native as the season progressed. September interaction networks were the most connected, nested, and least compartmentalized, suggesting the system was more stable and resilient later in the season. Our findings demonstrate that emergent wetlands hold the most value to wild bees in the latter half of the growing season. Many of the flowering plants of greatest importance for pollinators are also of high food value to waterfowl, making pollinator conservation compatible with existing wetland management. Emergent wetlands are a critical late-season component of a diverse landscape needed to support the full breadth of our native bee pollinators.