First-ever national wild bee map reveals farmland at risk
The new study finds that if losses of wild bees continue, United States crop production could be destabilized.
We've said it again and again, so excuse me for saying it again, but the bees are in trouble and we have to do something. While every species plays a role in the ecosystem, we are directly reliant on bees for pollinating the plants that feed us. But while most of the focus has been on commercial honeybees, our wild apian friends are in trouble too.
With that knowledge in hand, a team of researchers created the first national study to map U.S. wild bees. What they found confirms that our native buzzing pollinators are disappearing from many of the country's most vital farmlands, from California's Central Valley and the Midwest corn belt to the Mississippi River valley.
© PNAS"If losses of these crucial pollinators continue, the new nationwide assessment indicates that farmers will face increasing costs – and that the problem may even destabilize the nation's crop production," notes the study, the findings of which were published in the Proceedings of the National Academy of Sciences.
Led by Insu Koh, the scientists estimate that wild bee abundance between 2008 and 2013 declined in almost one-quarter of the contiguous U.S. In addition 39 percent of U.S. croplands that rely on pollinators face a potentially debilitating mismatch between increasing demand for pollination and a diminishing supply of wild bees.
"Until this study, we didn't have a national mapped picture about the status of wild bees and their impacts on pollination," says Koh, a researcher at UVM's Gund Institute for Ecological Economics.
The report calls for seven million acres of land to be protected as pollinator habitat over the next five years. "It's clear that pollinators are in trouble," says Taylor Ricketts, the senior author of the study and director of UVM's Gund Institute. "But what's been less clear is where they are in the most trouble – and where their decline will have the most consequence for farms and food."
© PNASThe map shows 139 counties in key agricultural regions of California, the Pacific Northwest, the upper Midwest and Great Plains, west Texas, and the southern Mississippi River valley that appear to be most threatened by the mismatch between decreasing wild bee supply and increasing crop pollination demand. In particular, the study found that crops like pumpkins, watermelons, pears, peaches, plums, apples and blueberries which are most reliant on pollinators have the strongest pollination mismatch. "These are the crops most likely to run into pollination trouble," says Taylor Ricketts, Gund Professor in UVM's Rubenstein School of Environment and Natural Resources. "whether that's increased costs for managed pollinators, or even destabilized yields."
We've known for a while the culprits at play in the fate of wild bees – pesticides, climate change, and diseases. But the new research also suggests that turning bee habitat into cropland is to blame as well. In 11 key states where bee numbers are falling, the amount of land tilled to grow corn skyrocketed by a whopping 200 percent in five years. Former bee havens are now reserved for raising corn. "These results reinforce recent evidence that increased demand for corn in biofuel production has intensified threats to natural habitats in corn-growing regions," the new study notes.
"Wild bees are a precious natural resource we should celebrate and protect," says Ricketts. "If managed with care, they can help us continue to produce billions of dollars in agricultural income and a wonderful diversity of nutritious food."
"Now we have a map of the hotspots," adds Koh. "It's the first spatial portrait of pollinator status and impacts in the U.S."
The researchers hope the new tool will help protect wild bees and pinpoint habitat restoration efforts.
See all the data and maps at the University of Vermont website.