DOI: 10.5061/dryad.qv9s4mwhz
title: Data from: Wild bee abundance declines with urban warming, regardless of floral density

description: As cities expand, conservation of beneficial insects is essential to
 maintaining robust urban ecosystem services such as pollination. Urban
 warming alters insect physiology, fitness, and abundance, but the effect
 of urban warming on pollinator communities has not been investigated. We
 sampled bees at 18 sites encompassing an urban warming mosaic within
 Raleigh, NC, USA. We quantified habitat variables at all sites by
 measuring air temperature, percent impervious surface (on local and
 landscape scales), floral density, and floral diversity. We tested the
 hypothesis that urban bee community structure depends on temperature. We
 also conducted model selection to determine whether temperature was among
 the most important predictors of urban bee community structure. Finally,
 we asked whether bee responses to temperature or impervious surface
 depended on bee functional traits. Bee abundance declined by about 41% per
 °C urban warming, and temperature was among the best predictors of bee
 abundance and community composition. Local impervious surface and floral
 density were also important predictors of bee abundance, although only
 large bees appeared to benefit from high floral density. Bee species
 richness increased with floral density regardless of bee size, and bee
 responses to urban habitat variables were independent of other
 life-history traits. Although we document benefits of high floral density,
 simply adding flowers to otherwise hot, impervious sites is unlikely to
 restore the entire urban pollinator community since floral resources
 benefit large bees more than small bees.
description: # Data from: Wild bee abundance declines with urban warming, regardless of
 floral density
 [https://doi.org/10.5061/dryad.qv9s4mwhz](https://doi.org/10.5061/dryad.qv9s4mwhz) ## Description of the data and file structure ### Files and variables | File | Field | Explanation | | :------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | SitesSpp.csv | Each column represents one bee species. Each row represents one site. The cell value is the number of bees caught at that site for that species, using all methods (pan trap, vane trap, netting) throughout the project.  | | | SiteData.csv | column | definition | | | site | site name (corresponds to "site" column in SitesSpp) | | | parcel\_area\_m2 | area of property on which sampling was conducted in square meters | | | sample\_area\_m2 | yard area sampled (parcel minus house, driveway, inaccessible areas) | | | temp | season-long mean evening (19:00 - 21:00) temperature for each site (degrees C) | | | flordiv | mean number of taxa in bloom across sampling dates | | | imperv100 | percent impervious surface within 100m radius of the center of the site | | | imperv200 | percent impervious surface within 200m radius of the center of the site | | | imperv1000 | percent impervious surface within 1000m radius of the center of the site | | | florabund | mean across sampling dates of estimated floral density at site (flowers per acre) | | | ln\_florabund | florabund, natural-log transformed | | | all\_rich | richness of all bees (rarefied to 100 individuals) | | | sm\_rich | richness of bees with IT span &lt; 2mm (rarefied to 75 individuals) | | | lg\_rich | richness of bees with IT span ≥ 2mm (rarefied to 25 individuals) | | | all\_abund | total number of individual bees caught at site | | | sm\_abund | total number of bees of species with IT span &lt; 2mm | | | lg\_abund | total number of bees of species with IT span ≥ 2mm  | | | lnall\_abund | as above, natural-log transformed | | | lnsm\_abund | as above, natural-log transformed | | | lnlg\_abund | as above, natural-log transformed | | its.dryad.csv | row | unique ID per row. Each row represents one individual bee.  | | | site | site name (corresponds to "site" column in SitesSpp and in SiteData; however, its.csv includes additional sites that were not part of the sampling for the main project, yet also had its measured. All sites are in Raleigh, North Carolina. Descriptive site names (e.g., 'Across from Withers Hall' are all located on NC State University campus) | | | genus | genus | | | species | specific epithet | | | sci\_name | genus and species | | | sex | male, female, or 'hermaphrodite' | | | size\_mm | body length (head to abdomen) in mm; 'na' for specimens not measured | | | its\_mm | intertegular span in mm |