A new study finds that the yields of major crops in the United States are frequently limited by a lack of pollinators. The study also highlighted the value of America’s wild bees, estimating they boost yields for six of the country's seven major crops examined in the study to the tune of $1.5 billion a year, reports Susan Milius for Science News.
The study, published last week in the journal the Proceedings of the Royal Society B, collected data on insect pollination and crop yield from 131 farms in the United States and Canada. At the farms, the researchers focused on seven crops: apples, highbush blueberries, sweet cherries, tart cherries, almond, watermelon and pumpkin, reports Dharna Noor for Gizmodo.
The researchers counted bee visits to flowers on the farms to see which bees were pollinating them and collected data on the resulting crop yields. The team then used statistical models to determine whether those crops could have achieved even higher yields if they’d had more pollinators.
The study found that five of the seven crops are pollination-limited, “meaning crop production would be higher if crop flowers received more pollination,” study author Rachael Winfree, an ecologist at Rutgers University, explains in a statement. Apples, cherries and blueberries—all early spring crops—were most severely limited by the lack of pollination, per Gizmodo. The researchers also found honeybees and wild bees made similar contributions to crop pollination overall.
Winfree tells Science News that the impact of wild bees pollination, even in “intense production areas where much of the produce in the USA is grown,” was a “big surprise.”
Farms all over the country pay big bucks to bring in hives of honeybees to pollinate their crops, with almond growing in California being a particularly striking example. Yet, despite the intensive use of so-called managed honeybees, wild bees pollination services were valued at an estimated $1.06 billion for apple production, $146 million in watermelons and $145 million in sweet cherries, while also providing substantial benefits to tart cherry, blueberry and pumpkin yields, according to Science News.
That means the fate of America’s food supply is hitched, not just to the survival of domesticated honeybees, but to native pollinators as well. Recent research suggests that some wild species, such as bumblebees, are disappearing as climate change warms their habitat. Reporting on the study’s findings for National Geographic, Douglas Main writes that “in North America, you are nearly 50 percent less likely to see a bumblebee in any given area than you were prior to 1974.”
If large numbers of the roughly 5,000 bee species native to North America are being laid low by climate change, that’s bad news for human food production but they’re also threatened by pesticide, disease and habitat loss.
“An important step is to minimize the use of pesticides that are highly toxic to bees, particularly neonicotinoids,” Winfree tells Gizmodo. “Growers can also leave areas of semi-natural habitat on their farm, such as borders of crop fields, where bees can nest and forage on flowers.”
These strategies for helping native bees would also reduce stress on domesticated honeybees. If we don’t, the $50 billion worth of U.S. crops that are dependent on pollinators could fall into jeopardy.