A quarter of known bee species haven't been seen in more than 20 years

Jan. 22 (UPI) -- There's never been more data on the world's animal and plant populations, but despite the proliferation of public records on species abundance, many known bee species have disappeared from datasets.

According to a new survey, published Friday in the journal One Earth, roughly a quarter of known bee species haven't made an appearance in public records in more than 20 years.

"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," first author Eduardo Zattara, biologist at the Pollination Ecology Group from the Institute for Research on Biodiversity and the Environment, said in a news release.

Disappearance from the scientific record isn't proof of extinction. Many missing species have been rediscovered 30, 40 or 50 years later.

Still, the latest findings suggest a significant portion of bee diversity is struggling to cope with a combination of environmental threats, including habitat loss, pollution, parasites and climate change.

"It's not a bee cataclysm yet, but what we can say is that wild bees are not exactly thriving," said Zattara, a biologist at the Pollination Ecology Group from the Institute for Research on Biodiversity and the Environment.

Of course, the latest paper isn't the first to sound the alarm on the plight of pollinators.

But while most studies have focused on specific bee species or habitats, the latest survey took a more macro approach, amalgamating and analyzing databases on bee abundance and diversity to identify global trends.

"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?"

For their study, Zattara and his colleagues leaned heavily on the Global Biodiversity Information Facility, an international network of datasets featuring more than 300 years of museum and academic records, as well as data collected by citizen scientists.

The database contains records of more than 20,000 known bee species from all over the globe.

When scientists analyzed the datasets for global trends in diversity and abundance observations, they found certain groups of bees are experiencing pronounced declines.

The data showed records of halictid bees, the second most abundant bee family, have declined by 17 percent since the 1990s. The more elusive Melittidae family has declined by 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."

According to the study's author, their work wasn't intended to pinpoint the disappearance of specific species, but to confirm that what scientists are observing locally seems to be congruent with what's happening globally.

"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."