USDA – Article by Julie Debes. Everyone knows that bees need flowers. But you might not know that most bees also need bare ground.
About 70% of the estimated 4,000 bee species in the United States build their nests underground each spring. This means they need access to very small patches of bare ground. When the soil is covered in dead leaves and other litter, these bees have less space to lay eggs and raise their young.
Livestock like sheep and cows help clear out litter on rangelands in the American West by grazing or with their hooves.
New USDA-Conservation Effects Assessment Project (CEAP)-funded research from Montana shows that pastures where livestock are grazing have twice as many ground-nesting bees. This means that in addition to providing food, fiber, and carbon storage for America, working rangelands give us plenty of pollinators, too.
Why Pollinators Matter
Up to $550 billion worth of global food supplies for people are pollinated by insects like bees. Pollinators are also essential for feeding wildlife. Animals from tiny warblers to giant grizzly bears munch on protein-rich beetles, butterflies, and other insects. Plus, pollinators help create healthy, productive soils.
Sadly, pollinators worldwide are at risk from pesticides, conversion of native landscapes, climate change, and disease. Activities that maintain or restore pollinators’ habitat—like sustainable livestock grazing on rangelands—are important for people and the planet.
In the Lower 48 where rangelands cover one-third of the landscape, native bees are the main pollinators. Female ground-nesting bees dig out small nests in the soil where they pack brood chambers with pollen, then deposit eggs.
Ground litter hinders bees’ nest building. Plus, fewer bees would survive when emerging from their underground nest if they have to fight up through dense leaf litter.
Livestock Grazing Gives Pollinators a Boost
Researchers from Montana State University recently examined the abundance of bees on rangelands with funding from the Natural Resources Conservation Service’s (NRCS) Working Lands For Wildlife initiative and CEAP. They compared pastures that were actively grazed—including those enrolled in NRCS grazing plans through the Sage Grouse Initiative—to pastures that sat idle for several years.
Results showed double to triple the number of ground-nesting bees on grazed pastures compared to un-grazed pastures. This increase was likely because grazed pastures had nearly twice as much bare ground and half as much leaf litter as un-grazed pastures.
“I think some people have the misconception that leaving everything alone is the best way to take care of the land, but livestock rejuvenate everything,” said Ben Lehfeldt, a fifth-generation sheep and cattle rancher in Lavina, Montana. His family volunteered their pastures as part of Montana State University’s ground-nesting bee research and is also enrolled in the Sage Grouse Initiative.
“Grazing land the right way makes better soil and more insects, and that increases the overall productivity for livestock,” Lehfeldt said, who is also the vice-president of the American Sheep Industry Association.
The new findings from Montana show that, in addition to maintaining wildlife habitat and supporting rural communities, livestock grazing also helps pollinators thrive. That means when we lose rangelands in the American West to development or cropland conversion, we also lose pollinators.
“For people who like to see cows not condos this is great data,” said Hayes Goosey, Extension Forage Specialist and entomologist at Montana State University who led the study. “It’s one more check in the box that livestock agriculture on rangelands is a good thing.”
Previous research by Goosey in Montana found that grazed pastures also boast a higher abundance and diversity of insects that birds prefer to dine on. “Grazing is positive for the arthropods that sage grouse eat. Now we know it’s also positive for pollinators,” Goosey explained. “And the more bees, the better, for everyone.”
This is just one of many recent NRCS projects that builds on research that helps inform data-driven decision making for pollinator conservation. Prescribed grazing and brush management are just two of the 51 NRCS grazing practices included in a recent Conservation Effects Assessment Project, that were proven to provide benefits to pollinators. Another recent CEAP project also provided findings to help guide decisions on which wildflowers to plant to best support native bees, resulting in researchers working with NRCS to develop a seeding mix for the southeastern U.S. You can read more about both projects, and additional pollinator resources by visiting the CEAP wildlife assessment web page.
Julia Debes is the Director of Communications for Working Lands for Wildlife in the West