Dwindling numbers of pollinators threaten global food security

In the largest study of its kind, scientists at Rutgers University have found that declining numbers of bees and other pollinators threaten crop yields and global food security.

The crops that depend on pollinators generate more than $50 billion a year in the U.S. alone. According to the research, crop yields for apples, cherries and blueberries have already dropped in the U.S. due to a lack of pollinators. 

Study senior author Rachael Winfreen is a professor in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick.

“We found that many crops are pollination-limited, meaning crop production would be higher if crop flowers received more pollination. We also found that honey bees and wild bees provided similar amounts of pollination overall,” said Professor Winfreen.

“Managing habitat for native bee species and/or stocking more honey bees would boost pollination levels and could increase crop production.”

Recent studies have shown that European honey bees and some native wild bee species are in a state of decline. The researchers noted that pollination by both wild and managed insects is critical for crop productivity, including those providing micronutrients that are essential for global food security. 

The current study, which was led by research associate James Reilly, was focused on 131 farms across the United States and British Columbia. The scientists collected data on insect pollination of crop flowers and yield for apples, blueberries, sweet cherries, tart cherries, almond, watermelon, and pumpkin. 

Overall, the crops that showed evidence of limited productivity due to a lack of pollination were apples, sweet cherries, tart cherries, and blueberries. 

“Our findings show that pollinator declines could translate directly into decreased yields for most of the crops studied,” said the researchers. In addition, the study revealed that wild bees and honey bees contribute nearly the same level of pollination.

“Our study reconciles previous conflicting evidence for the relative importance of honey bees, a managed agricultural input that growers must pay for each year, and wild bees, which provide a free ecosystem service, in pollination of crops grown across the United States,” wrote the study authors.

“Previous national-level studies of the USA have estimated honeybees to be much more important than wild bees, but did not actually measure wild bee abundance in crop fields. By contrast, more recent syntheses of global literature have concluded wild bees may be at least as important as honeybees, if not more so.”

The findings suggest that adopting practices to conserve or augment wild bees, such as enhancing wildflowers and using managed pollinators other than honey bees, could substantially boost crop yields. 

The study is published in the journal Proceedings of the Royal Society B: Biological Sciences.

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By Chrissy Sexton, Earth.com Staff Writer