In a new study published by Cell Press, experts report that a quarter of all known bee species have not appeared in public records since the 1990s, even though the number of available records has increased.
A lack of recorded data does not necessarily mean that the bees have all gone extinct, but it does suggest that the bees have become so rare that no one is observing them in nature.
Study first author Eduardo Zattara is a biologist at the National Scientific and Technical Research Council (CONICET) in Argentina.
“With citizen science and the ability to share data, records are going up exponentially, but the number of species reported in these records is going down,” said Zattara. “It’s not a bee cataclysm yet, but what we can say is that wild bees are not exactly thriving.”
Most previous studies focused on declining bee populations have investigated a specific region or a single bee species. For the current study, the researchers set out to identify more general, global trends in bee diversity.
“Figuring out which species are living where and how each population is doing using complex aggregated datasets can be very messy,” said Zattara. “We wanted to ask a simpler question: what species have been recorded, anywhere in the world, in a given period?”
The experts turned to the Global Biodiversity Information Facility (GBIF), an international network of databases that contains over 300 years of records from museums, universities, and private citizens. Overall, the data includes over 20,000 known bee species from around the world.
The analysis revealed that a quarter of all bees are missing from the records, and that these absences are not evenly distributed among bee families. For example, records of halictid bees have declined by 17 percent since the 1990s, while records of the rare bee family Melittidae have declined by as much as 41 percent.
“It’s important to remember that ‘bee’ doesn’t just mean honeybees, even though honeybees are the most cultivated species,” said Zattara. “Our society’s footprint impacts wild bees as well, which provide ecosystem services we depend on.”
“It’s not really about how certain the numbers are here. It’s more about the trend. It’s about confirming what’s been shown to happen locally is going on globally. And also, about the fact that much better certainty will be achieved as more data are shared with public databases.”
Still yet, the researchers warn that this type of certainty may not come until it is too late to reverse the decline, which may not be possible in the first place.
“Something is happening to the bees, and something needs to be done. We cannot wait until we have absolute certainty because we rarely get there in natural sciences,” said Zattara. “The next step is prodding policymakers into action while we still have time. The bees cannot wait.”
The study is published in the journal One Earth.