Data from: Bee communities along a prairie restoration chronosequence: similar abundance and diversity, distinct composition

Recognition of the importance of bee conservation has grown in response to
declines of managed honey bees and some wild bee species. Habitat loss has
been implicated as a leading cause of declines, suggesting that ecological
restoration is likely to play an increasing role in bee conservation
efforts. In the Midwestern USA, restoration of tallgrass prairie has
traditionally targeted plant community objectives without explicit
consideration for bees. However, restoration of prairie vegetation is
likely to provide ancillary benefits to bees through increased foraging
and nesting resources. We investigated community assembly of bees across a
chronosequence of restored eastern tallgrass prairies and compared
patterns to those in control and reference habitats (old fields and
prairie remnants, respectively). We collected bees for three years and
measured diversity and abundance of in-bloom flowering plants, vegetation
structure, ground cover, and surrounding land use as predictors of bee
abundance and bee taxonomic and functional diversity. We found that
site-level variables, but not site type or restoration age, were
significant predictors of bee abundance (bloom diversity: p = 0.004, bare
ground cover: p = 0.02) and bee diversity (bloom diversity: p = 0.01).
There were significant correlations between overall composition of bee and
blooming plant communities (mantel test: p = 0.002), and both plant and
bee assemblages in restorations were intermediate between those of old
fields and remnant prairies. Restorations exhibited high bee beta
diversity, i.e., restored sites’ bee assemblages were taxonomically and
functionally differentiated from each other. This pattern was strong in
younger restorations (< 20 years old), but absent from older
restorations (> 20 years), suggesting restored prairie bee
communities become more similar to one another and more similar to remnant
prairie bee communities over time with the arrival of more species and
functional groups of bees. Our results indicate that old fields,
restorations, and remnants provide habitat for diverse and abundant bee
communities, but continued restoration of old fields will help support and
conserve bee communities more similar to reference bee communities
characteristic of remnant prairies.