Identifying key forage plants to support wild bee diversity and a species at risk in the Prairie Pothole Region

Global wild bee declines have been well documented in recent decades, with a regularly cited driver being habitat loss and the associated reduction of food and nesting resources. In North America's Prairie Pothole Region, habitat loss is largely attributed to agricultural intensification, resulting in the reduction of once common native grasslands surrounding wetlands. Although restoration of these grassland–wetland complexes has been implemented across the region, wild bees are not often the primary target for recovery. Restoration efforts may better support wild bees by including specific flowering plants (i.e. food resources) intended to provision the highest diversity of taxa; however, very little information is available specific to this region, which covers over 700 000 km2 in Canada and the United States. Our objective is to inform habitat restoration intended to support wild bee conservation through the addition of targeted flowering plant species at restored sites. As such, we used a model‐based approach to identify 16 key flowering plants present in remnant grassland–wetland complexes that are highly visited by diverse wild bee species, as well as by Bombus terricola Kirby, which is a species at risk in this region. The key plants represented eight families and supported approximately 82% of all visits from 69 out of the 75 observed bee species. By incorporating the recommended floral resources into restoration practices in the Prairie Pothole Region, practitioners can more efficiently mitigate the habitat loss that is thought to be a major driver of wild bee decline. We used observed interactions and a model‐based approach to identify flowering plants in remnant grassland–wetland complexes that supported the highest diversity of wild bee species, including a species at risk. We identified 16 plant species from eight families that supported about 82% of all wild bee visits from 69 out of the 75 observed bee species (21 of the observed 24 genera). This supports that a small number of plants can provision a high proportion of the visiting wild bee community and provides insight for future bee‐targeted restoration in this region.