A new study published Thursday in the journal Science has found that bumblebees are becoming increasingly more threatened as the effects of climate change decrease populations in North America and Europe, reported CNN. In fact, the study found that the odds of seeing a bumblebee have decreased by 30 percent since the 20th century.
Researchers from the University of Ottawa in Canada studied 66 bumblebee species across North America and Europe, tracking changes in their populations over time. They then compared any changes observed with climate-related changes also occurring in the same areas.
Pulling data from over 550,000 records, researchers estimated the distribution of bumblebee populations across both continents during two distinct time periods: from 1901 to 1974, and then from 2000 to 2015. They also pulled data on average monthly temperatures and total precipitation in the areas studied, examining specifically if these changes exceeded the bees’ tolerance level.
The researchers discovered that as temperature and precipitation-related climate changes increased, so did the bumblebees’ risk for extinction. They believe this happens because bees are unable to tolerate extreme changes in temperature and precipitation, causing them to die off.
The scientists note that bees prefer cooler and slightly damp climates in addition to a variation in seasons. As climate change contributes to hotter temperatures and dryer habitats, bees are less likely to colonize these areas and increase their number.
On both continents, researchers found a quick and widespread decline in bumblebee populations. Compared with the number of bees found between 1901 and 1974, the likelihood that a bumblebee species would be present in North America between 2000 and 2015 dropped by 46 percent, and in Europe, by 17 percent.
Dr. Jeremy Kerr, senior author of the study and a biology professor at the University of Ottawa, commented on how quickly the environment is changing over a relatively short period of time, noting that children born in the 21st century will not be able to experience the same environment that their parents and grandparents did.
“The things [we] grew up with as kids are fading away very fast. It’s not just that we’re looking at what our kids will experience; it’s that we are looking back not even a full generation, just to when we were kids, and saying, ‘Could we take our children to places we loved and find what we found?’ What our study says is that that answer is no across entire continents.”
The loss of bumblebees contributes to decreasing biodiversity and impairment of ecosystem services. Plants and crops are also impacted by the decrease in bee populations, while some may be in danger of disappearing altogether.
Despite the study’s bleak findings, researchers believe that with proper conservation efforts, bees have a chance for survival.