Pollinators play a critical role in food production. According to the USDA Farmers.gov website, more than 80 percent of the world’s flowering plants need a pollinator to reproduce. Since most of our food comes from flowering plants, we need pollinators too. It is estimated pollinators provide ecological services valued at $200 billion each year.
Dramatic drops in bee populations and other pollinator species across North America have raised alarms. On the February 4 Strategic Farming: Let’s talk crops program, Dan Cariveau, associate professor with the University of Minnesota Bee Lab, along with moderator Claire LaCanne, UMN Extension educator in crops, discussed pollinators and how we can promote them on an agricultural landscape.
At least 20,000 species of bees have been identified across the world. Minnesota alone has about 525 species of bees, ranging from tiny species you can just see with the naked eye to very large bumblebee species. Flowers and bees are closely linked, with bees being a critical pollinator of flowers.
Cariveau’s lab specializes in native bee species. Many of these are considered groundnesting bees (about 80%). Although there is much diversity among bees, one thing remains constant, and that is that bees rely on flowers for all of their life cycle.
Bees are sensitive to loss of habitat, changes in climate, and disease. The rusty patch bumblebee, for example, used to be relatively common across much of the northeastern U.S. and Upper Midwest. Now it is all but extinct over much of its old habitat, being found in just a few locations including in MN, and it has been listed on the Endangered Species list since 2017. Loss of habitat is a key factor Cariveau and others in conservation have been focusing on.
Bees need food (flowers) and nesting resources to lay their eggs so creating and restoring habitat is critical if we want to help increase and support their numbers. Cariveau’s research team found that the amount of agricultural ground surrounding an area did not seem to influence the number of bee species present. The number of different flower species on the landscape, however, enhanced the number of bee species present.
Research with bumblebees found that the number of plant species in a CRP mix did not affect the number of bumblebees or number of bumblebee species present compared to a remnant prairie site. More flowers, however, meant more bees.
Research conducted across SW MN looked at the impacts of the amount of natural habitat surrounding a planting, size of the pollinator habitat (2 acres compared to 11 acres), and species diversity (the cheaper 8 species mix was about 1/8 the cost of the 40 species forb mix) on native bees. They found that bee diversity and bee abundance was not impacted by the type of seed mix used, or the amount of natural habitat that surrounded the restored areas.
As long as flowers were present, the bees came. This means that rather than spending a large amount of money on a highly diverse mix for a single restoration area, more areas could be planted with a less diverse, less expensive mix that produces flowers, resulting in greater habitat areas across the landscape. As far as size of habitat, even a small flowering garden provides beneficial habitat for bees.
It was also noted that although soybeans are a selfpollinating species, a summary of research published by Iowa State University found that wild bees and honeybees can improve soybean yields up to 20% when they are around to help pollinate soybeans.
Access a recording of the full program at z.umn.edu/strategicfarming.
Thanks to the Minnesota Soybean Research and Promotion Council and the Minnesota Corn Research and Promotion Council for their support of this program.
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