Sept. 12, 2008 -- Roadsides may seem like the crummiest real estate around, but new research suggests that in fact they could serve as nature preserves for crucial pollinators, particularly native bees.
Roadsides planted with native plants hosted more than twice as many total bees and almost 50 percent more bee species than roadsides covered in non-native grasses, according to the study, published in Biological Conservation.
Jennifer Hopwood made the discovery while in graduate school in ecology at the University of Kansas in Lawrence. She started the research after picking up a book on roadside ecology from her colleague's desk and starting to read.
"I just became really interested in the idea that roadsides could be potential habitat for animals and could also be a haven for plant species," she said.
Several programs have restored the plants along roadsides in the Midwest to native species, which offer advantages over the non-native plants that were once recommended.
Native plants have deep roots, so they help prevent erosion, and they require less mowing and herbicide use, which saves on maintenance costs, although the up-front cost of planting and establishing the native grasses is higher.
But Hopwood's primary interest was in bees, so she began investigating bees' success in such habitats.
Hopwood collected bees from several roadside sites in Kansas that had been restored to native plants, and compared them with nearby, unrestored roadsides. Not only did Hopwood find that native plants hosted more than twice as many bees and almost 30 more types than weedy sites, but she also found that this relationship held regardless of how many flowers were present.
"Even if there were a ton of exotic flowers, the roadsides that had native flowers in them still attracted more bees," Hopwood said.
The width of the roadside did not make a difference in Hopwood's findings, suggesting that even narrow roadsides can act as refuges for native bees.
The bees seemed to fare fine despite their proximity to speeding windshields: There were no fewer bees in plots next to heavily trafficked roads than in less-trafficked areas.
Native-planted roadsides, which are not tilled like agricultural lands, and which have more open ground than weedy roadsides, also provide good spots for native ground-nesting bees to settle in, Hopwood said.
The findings suggest that the more than 10 million acres of roadside in the United States could serve as a valuable, interconnected source of habitat for native bees, whose populations have declined in recent years. Experts also have hopes for native bees to help with the crucial pollination of agricultural plants since honeybee numbers have crashed from colony collapse disorder.
"The idea of taking what people often refer to as junk land, and, with just a little bit of effort, creating this haven for these grassland species is a way to make a difference," said Kimberly Russell of the American Museum of Natural History in New York. "We're going to sprawl, but if you can do these little things to bring in native species, that's a really good thing.
"It's not going to cure everything." Russel added. "You can't say, 'OK, we've got the roadsides to we don't need to worry about prairie anywhere else.' But I think taking this kind of management seriously could go a long way."
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