A growing body of research indicates that cities can support diverse bee communities. However, urbanization may disproportionately benefit exotic bees, potentially to the detriment of native species. We examined the influence of urbanization on exotic and native bees using two datasets from Michigan, USA. We found that urbanization positively influenced exotic – but not native – bee abundance and richness, and that this association could not be explained by proximity to international ports of entry, prevalence of exotic flora, or urban warming. We found a negative relationship between native and exotic bee abundance at sites with high total bee abundance, suggesting that exotic bees may negatively affect native bee populations. These effects were not driven by the numerically dominant exotic honeybee, but rather by other exotic bees. Our findings complicate the emerging paradigm of cities as key sites for pollinator conservation.
R scripts for data analysis
R markdown file including all scripts for collating and analyzing data and preparing figures for manuscript.
Distance to registered ports of entry
.csv file with distance in m from all field sites to the two registered ports of entry in SE Michigan
2014 temperature data
Data on maximum, minimum, and mean temperature recorded at each site by data loggers during 2014 sampling period.
2017 temperature data
Data on maximum, minimum, and mean temperature recorded at each site by data loggers during 2017 sampling period.
Data on proportion of developed land around each field site within 4 concentric buffers: 500m, 1000m, 1500m, and 2000m.
2017 bee specimens - no honeybees
Data on all specimens collected via pan traps and netting during 2017 sampling period, with Apis mellifera (European honeybee) specimens removed.
2017 bee specimens - with honeybees
Data on all bee specimens collected via pan traps in 2017, including Apis mellifera (European honeybee).
2014 bee specimens - no honeybees
Data on all specimens collected via pan traps and netting during 2014 sampling period, with Apis mellifera (European honeybee) specimens removed.
2014 bee specimens - with honeybees
Data for all bee specimens collected via pan traps during 2014 sampling period, including Apis mellifera (European honeybee).
Metadata for flowering plants observed
Information on the geographic origin and plant type (crop, ornamental, wild) for each flowering plant found during surveys in 2014 or 2017.
2017 flowering plant data
Information on all flowering plants found during surveys in 2017, including species identity and abundance.
2014 flowering plant data
Information on all flowering plants found during surveys in 2014, including species identity and abundance.
Site-level summary of floral resource availability for each survey
Data on floral abundance and cover for each site at each survey period in both 2014 and 2017.