SFU study finds overall bee population decline exaggerated

New modelling shows which species need the most help

Written by: Carter Hemion, Staff Writer

While some bee populations are in danger, average population declines have been exaggerated, according to a new SFU study. Where some studies have shown rapid and severe decline in many species, the situation is not as dire as previously thought, and research may help focus bee conservation on the species most in need, like the endangered Bombus bohemicus.

Researchers Dr. Laura Melissa Guzman, Dr. Leithen M’Gonigle, Dr. Arne Mooers, and PhD candidate Sarah Johnson documented information about bee populations with a new research model. 

Lead author Guzman said she read a study last year that showed bee populations dropping drastically, and her team was curious about how the data was collected. “We decided to do the simulations to figure out whether different modeling decisions could affect or bias your results.” 

In the SFU study, data was collected from observations in bees’ natural habitats. The information on what species were observed, when they were seen, and where they lived came from museum data, historical records, and citizen science observations — such as apps like Bumble Bee Watch and iNaturalist

Where the initial study observed species in North America and Europe, not all species were observed in their native habitats. Some North American species had been observed in Europe and vice versa, which may have affected results, according to Guzman. Some of the first study’s data may also have been inaccurate from counting no bees present when the bees were likely unobserved on that particular day, Guzman explained. 

Guzman noted it’s particularly important to identify “which species are declining and why.” The team collected data where species could naturally be found, and compiled data from what had been observed elsewhere.

While the initial study saw a 46% loss of North American bee populations in the last century, the SFU study found that only 5% of the total population had been lost with their observations. 

While some species saw declines, others remained unchanged. Bombus bohemicus —  a parasitic bumble bee — had one of the largest observed declines due to a decrease in its hosts, according to Guzman. Other species, like bombus cryptarum, increased their populations from taking advantage of environmental changes. With these observations on various species, more at-risk species can be prioritized in finding solutions, according to Guzman.

“It’s really important to focus on bee conservation.” She said we depend on pollinators like bees to “pollinate up to 75% of all our crops,” which keeps our food system healthy. Pollinators are especially important in BC for plants like blueberries and tomatoes. According to Guzman, bee decline may be a result of climate change, pesticide use, lack of host species, and other factors. Models like her team’s study can help discover and address these concerns.

To support conservation efforts, it is important bees have enough floral resources. They need floral diversity, enough habitat space, and areas without pesticides. Planting native plants and pollinator strips in an effort to support pollinators may be a solution to some issues. 

Though some bee species are struggling, this study observes that not all bees are in as much danger as previously thought. Guzman said, “There are some species that are able to take advantage of some of the agricultural changes that we’ve had, and so it doesn’t mean that it’s doom and gloom for every single species.”