Posted: March 30, 2023

Over a six-year period in southcentral Pennsylvania, biodiversity among wild bee communities declined and one-third of species decreased in abundance, according to a Penn State-led study.

"Bees are one of the most important groups of pollinators," said lead author Nash Turley, postdoctoral scholar in entomology. "Tracking changes in bee biodiversity is important for developing pollinator management plans that can help sustain wild plant communities and maximize crop yields."

To measure shifts in bee biodiversity and changes in abundance of specific species, the researchers sampled bees at eight locations in Adams County from 2014 to 2019, examining more than 26,700 individual bees representing five bee families, 30 genera and 144 species.

Over the study period, the average abundance of bees captured declined by 48%, and the number of species detected fell by 41%, the researchers noted. About one-third of the species for which researchers had sufficient data declined in abundance. Many of the declining species were bumble bees and sweat bees.

"Little is known about what wild bee species or groups have the greatest conservation needs," said co-author Margarita López-Uribe, associate professor of entomology. "Our findings could help to quantify the effects that different aspects of environmental change have on bee communities and to identify species of conservation concern."

--Chuck Gill