Fighting to Understand Bees in Decline

News stories about colony collapse have made it clear: bees are in trouble. Widespread pesticide use and habitat loss have had a devastating effect on bee populations around the country. While awareness of human impact on pollinators is improving, we’re still learning about the diversity of wild bees that populate our landscape.

Local environmental scientist Scott Haire works at the Metropolitan Council on Water Resource Management monitoring the water quality of 21 streams around the Twin Cities. But in his spare time, he studies native bees, seeking to identify and catalog the more than 350 species of native bees that call Minnesota home. 

“Because we don’t have a good understanding of what bees are here, it’s hard to know which populations are declining,” he said. For example, the rusty patched bumblebee is one pollinator that has been hit hard in recent years. Its population has dropped up to 87%, and it’s now considered an endangered species. 

When colony collapse began to make news, Scott was in the field, working with kids to map bee burrows in the Science Museum’s Saint Croix Watershed Research Station. The connection between bees and the health of the environment couldn’t be clearer to Scott, who continues to volunteer with the Science Museum as they race against time to identify native bee species before they disappear.

Beyond honeybees and bumblebees

Honeybees get credit for pollinating most crops, but they actually only arrived in North America with the first European settlers. Long before the European honeybee reached our shores, wild bees filled the landscape, pollinating wildflowers and crops. In fact, wild bees tend to do a better job of pollinating because they flit between flowers more often than honeybees, spreading more pollen between blossoms.

Less than 2% of the bee species that live here are honeybees or bumblebees. The vast majority of wild bees in Minnesota are “solitary” bees that live on their own rather than in a colony or hive. Depending on the species, certain solitary bees nest in burrows underground while others prefer hollow plant stalks or holes left in wood by beetles. As scientists continue to learn about these species, new efforts are underway to support bee habitat around the Twin Cities.

Many local organizations are promoting pollinator education and bee-friendly gardening. Scott is encouraged by the work of the University of Minnesota’s Bee Lab and the Xerxes Society, which promote insect protection through outreach and citizen science programs. 

Citizen scientists play an important role in the ongoing study of Minnesota’s bees. Beekeepers can help monitor their honeybees for parasitic mites, and residents anywhere in the state can submit anecdotal bumblebee sightings to the MN Bee Atlas.

A new grant program from the Minnesota Board of Water and Soil Resources called Lawns to Legumes is geared toward encouraging residential landowners to plant native, pollinator-friendly gardens. Homeowners can sign up for updates about available resources to support converting their garden to native plants.

Making space for solitary bees

You can help at-risk species like the rusty patched bumblebee by planting a variety of flowering plants that bloom throughout the growing season. The Bee Lab supplies a list of recommended plants that will draw a diverse array of bees to your yard.  

An often overlooked garden feature is open spaces for ground-nesting bees. Consider using rocks instead of mulch to create a path through your yard or garden. Open patches of undisturbed soil around rock features and native grasses create space for these solitary bees to make a home underground. 

You can also offer shelter to cavity-nesting bees by making a bee box or “bee house” out of a woodblock or bundle of bamboo. Cavity nesting bees deposit a single egg atop a lump of pollen in the back of a bee box’s hollow tunnel and then seal the tunnel with mud. Over the course of a year, the egg will pupate and emerge from the bee house. The Bee Lab website provides detailed instructions on many different kinds of bee boxes that are quick and easy to make. 

This fall, resist the urge to cut back any tall dead plants because bees will hibernate in hollow stalks. While most bees are already hibernating, you may still see bumblebees in your garden. Their big, fuzzy bodies are better adapted to the northern climate, allowing them to continue flying in temperatures as low as 60 degrees. 

Creating pollinator habitat goes hand-in-hand with protecting water quality. Impervious surfaces like pavement create runoff that carries pollutants into our lakes and streams. Gardens near the shoreline that are filled with native, pollinator-friendly plants provide a habitat for bees and a buffer zone that absorbs runoff. Native grasses and wildflowers can prevent erosion along the water’s edge with root systems that grow up to eight feet deep.

 There’s plenty of opportunities for Twin Cities residents to fight for pollinators in their own backyards. With a little planning, your yard can become a wild bee refuge.