Restoration on the Prairie
In 1986, when The Nature Conservancy started protecting land at Nachusa Grasslands in Illinois, only a few remnants of undisturbed tallgrass prairie remained. Most of the surrounding land had been converted to agricultural use—growing corn, soybeans and other crops.
Thirty years of conservation and restoration efforts have made a world of difference. Today, more than 3,000 acres have been protected at Nachusa. Volunteers have harvested and planted thousands of pounds of native prairie plant seeds to create a large expanse of restored tallgrass prairie. Managers use controlled fire and grazing by a reintroduced bison herd to maintain the prairie.
There’s no denying that this restored habitat is good for bison, birds, turtles and many other charismatic critters, but what about smaller, but nonetheless ecologically important species like bees? Loss of habitat is one the leading causes of bee decline, but does restoring prairie habitat bring back bees?
Biologists Bethanne Bruninga-Socolar and Sean Griffin from Rutgers University have been studying this question at Nachusa Grasslands Preserve since 2013.
A volunteer collects native seeds for restoration efforts at Nachusa Grasslands. © Anne E. Cutting
If You Restore It Bees Will Come
“There’s an assumption that the restoration of habitat promotes the return of native creatures,” explains Bethanne. “We wanted to test whether this was true of bees and, if so, to what extent.”
In 2016, Bethanne and her colleagues collected an astonishing 72 species of bees at Nachusa. Their study confirmed that if prairie habitat is restored, bees will repopulate it.
Bethanne and Sean used traps to collect bees from agricultural fields surrounding Nachusa, as well as from prairie sites within the preserve. The agricultural fields have the lowest levels of plant diversity in the area, while remnant prairies—those that have never been planted with crops—have the highest plant diversity. Sites that have been subject to restoration for different lengths of time provide intermediate levels of plant diversity.
Bethanne and Sean used a sampling method known as chronosequencing. Sometimes explained as “substituting space for time,” chronosequencing allows researchers to observe how a bee community’s abundance and diversity change over time without needing years of observation. By sampling bees from restored prairie sites ranging in age (time since seeding) from 2-26 years, they gain insight that would have taken nearly three decades to record.
A researcher deploys bee traps at Nachusa Grasslands. © Gabriella Pardee
Great News for Land Managers—and Bees
The researchers found that the longer prairie restoration efforts go on, the more bee diversity returns to restored sites. After just five to seven years, bee communities at restored prairie sites show diversity levels that are similar to those at remnant prairie sites.
For prairie managers, this is great news. It affirms that current prairie restoration techniques promote healthy bee communities.
“It’s validation of what he had hoped for,” said Jeff Walk, director of conservation for the Conservancy in Illinois. “It’s fulfilling to see that we’re successfully helping restore the whole prairie ecosystem, not only the plants.”
Bee at Nachusa Grasslands in Illinois. © Charles Larry
Flowers, Fruits and Veggies
Across the globe, bees are the most ecologically important creatures when it comes to pollination. Roughly 87 percent of all flowering plants require pollination, and the vast majority are pollinated by bees.
“Bees are highly adapted pollinators,” said Bethanne. “They have developed unique traits specifically for pollination. For instance, their fuzzy hairs are ideally suited for holding pollen. We don’t see pollination-specific adaptations such as this in any other pollinator species.”
Bees may sometimes be an annoying, uninvited picnic guest, but before you swat them away, consider that they made your picnic possible.
“Bees are fundamentally important to our food crops. If you like any fruits or vegetables, you have a bee to thank. We should appreciate the job that bees do every time we sit down to a plate of fruits or veggies,” explained Jeff.
Be Kind to Bees
“Bees are often mistaken for wasps,” says Bethanne. “True bees are remarkably non-aggressive and remarkably uninterested in people. I spend a lot of time with my hands very near bees and I’ve only been stung 3 times—each because a bee had become trapped in my clothing.”
If you’d like to help bees around your home, consider installing a pollinator garden that provides array of native plants blooming throughout the entire season and avoid using insecticides. For more tips, check out Habitat Network.