COS 271-2 - Does establishing native wildflowers on vacant land aid bee conservation in a legacy city?

Abstract: Legacy cities are afflicted with economic disinvestment, decreasing populations, and numerous social and political challenges. As people leave legacy cities, abandoned homes are eventually demolished and transformed into vacant lots. Although there are many challenges associated with vacancy, these greenspaces have been demonstrated to provide habitat for urban wildlife and provide some ecosystem services for local communities. Vacant land is managed with monthly mowing and supports abundant bee forage in the form of urban spontaneous vegetation. In the legacy city of Cleveland, Ohio, 30% of the state’s bee fauna has been collected within vacant lots. Our goal was to determine if transforming vacant land into small native wildflower plantings would result in a higher abundance and richness of wild bees using these sites compared to vacant lots. Our approach was to establish the Cleveland Pocket Prairie Project which incorporated a network of vacant lots and pocket prairies in this legacy city. We compared bee communities in these habitats with peri-urban grasslands maintained by the Cleveland Metroparks system within surrounding suburban landscapes. Our hypothesis was that urbanization would strongly filter the bee community able to colonize pocket prairies and vacant lots. However, we predicted that establishing plantings of native wildflowers would attract and retain a higher abundance and richness of wild bees. Using pan traps and hand vacuums, we sampled bees within each treatment from June to September 2019. We found 1,087 bees representing 24 genera and 83 species. Here, we show that bees visited over 30 floral species, ranging from native wildflowers to urban spontaneous vegetation. PERMANOVA analysis revealed that peri-urban grasslands supported bee communities that were distinct from those collected from pocket prairies and vacant lots, indicating that urbanization was a strong environmental filter. Interestingly, grasslands and pocket prairies generally supported a higher bee abundance and richness compared to vacant lots. Our results suggest that establishing native wildflower plantings can be a useful component of an urban conservation strategy for legacy cities.