“Knowing which species live in a place and how each of these complex datasets performs can be very confusing,” said Zatara. We wanted to ask a simpler question: What species have been observed, anywhere in the world, in a given period?
To find their answer, the researchers searched the Global Biodiversity Information Facility, an international network of databases containing records from museums, universities and individuals dating back more than three centuries and containing data on more than 20,000 known species of bees from around the world. .
Not only did the researchers discover that out of a quarter of the total number of bee species observed prior to 1990, no further observations were recorded between 2006 and 2015, they also found that the decline was not evenly distributed across families of different bee species.
Observations of bee species in the family Halictidae – the second largest family with a fairly common bee – have declined by 17 percent since the 1990s, while the Melictidae – a very rare family – have decreased by as much as 41 percent.
“It is important to realize that the word ‘bee’ does not mean honey bees only, although honey bees are the most widely cultivated species,” Ztara said. “Our community impact also affects wild bees, which also provide services for the ecosystem we depend on.”