The first-ever study to map U.S. wild bees suggests they’re disappearing in the country’s most important farmlands — from California’s Central Valley to the Midwest’s corn belt and the Mississippi River valley.
“This study provides the first national picture of wild bees and their impacts on pollination,” said Taylor Ricketts, Director of University of Vermont Gund Institute for Ecological Economics, noting that each year $3 billion of the U.S. economy depends on pollination from native pollinators like wild bees. Taylor, a conservation ecologist, spoke at the American Association for the Advancement of Science (AAAS) annual meeting panel, “Plan Bee: Pollinators, Food Production and U.S. Policy.” Taylor briefed scholars, policy makers and journalists on how the national bee map can help to protect wild bees and pinpoint habitat restoration efforts.
“Wild bees are a precious natural resource we should celebrate and protect,” said Taylor. The map identifies 139 counties in key agricultural regions of California, the Pacific Northwest, the upper Midwest and Great Plains, west Texas, and Mississippi River valley, which appear to have mismatch between falling wild bee supply and rising crop pollination demand.
Pesticides, climate change and diseases threaten wild bees — but their decline may be caused by the conversion of bee habitat into cropland, the study suggests.
A team of seven researchers — from University of Vermont, Franklin and Marshall College, University of California at Davis, and Michigan State University — created the maps by first identifying 45 land-use types from two federal land databases, including croplands and natural habitats. Then they gathered detailed input from national and state bee experts about the suitability of each land-use type for providing wild bees with nesting and food resources.
The scientists built a bee habitat model that predicts the relative abundance of wild bees for every area of the contiguous United States, based on their quality for nesting and feeding from flowers. Finally, the team checked and validated their model against bee collections and field observations in many actual landscapes.
“The good news about bees,” said Taylor, “Is now that we know where to focus conservation efforts, paired with all we know about what bees need, habitat-wise, there is hope for preserving wild bees.”
—University of Vermont press release
NewTerrain March 1, 2017