Urban Refuge: How Cities Can Help Rebuild Declining Bee Populations

The billowing stainless steel forms of Frank Gehry’s Pritzker bandshell seem to float up from behind the 3.5-acre Lurie Garden in Millennium Park, backed by Chicago’s celebrated skyline. Another landmark in a city long a laboratory for innovation in architecture and landscaping, the garden has been called a “model of responsible horticulture.” Masses of flowering perennials and grasses are a striking counterpoint to the surrounding walls of concrete and glass. Perhaps most unexpected, at a place that sits atop a 4,000-vehicle underground parking garage and railroad depot in the inner city, are the bees that flit from flower to flower.

In the 21st century, urban green spaces must be many things: verdant getaways, playgrounds, gathering spots. As cities continue to sprawl across the planet, leaving mere patches and fragments of wilderness in their wake, gardens increasingly must also serve as living space for native plants and animals. Not every species is amenable to city life, but from Berlin to Melbourne to Berkeley, researchers are finding that flower patches — in parks, residential properties, community vegetable plots, and vacant lots — support surprisingly healthy populations of bees, the most important pollinators in agricultural and most natural areas. In a few cases, urban bee populations are more diverse and abundant than those outside the city.

In fact, as Rebecca Tonietto was surveying bees in Chicago in 2008, just four years after the Lurie Garden opened to much fanfare, she made a remarkable discovery. Among the lanky sunflowers and bursts of purple bee balm was Lasioglossum michiganense, a native sweat bee never before found in Illinois, collecting pollen and nectar on the enormous green roof, the most urban of landscapes. 

Tonietto, a biologist at the University of Michigan-Flint, is co-author of a recent essay in Conservation Biology that points to research on urban bees as evidence that humans can share high-density habitat with other species. “Surrounded by increasingly less hospitable rural and suburban landscapes,” she and her colleagues write, the city “can become a refuge” for the bee species and other insects that are suffering significant declines.

“This means we can do some real conservation in cities,” not just public education and outreach, says Damon Hall, lead author of the essay and a biologist at Saint Louis University.

According to a report in the Proceedings of the National Academy of Sciences, from 2008 to 2013 bee abundance in the United States decreased most sharply in the Midwest corn belt and California’s Central Valley, where agricultural production has intensified. “Among the numerous threats to wild bees, including pesticide use, climate change, and disease,” the authors write, habitat loss seems to have been the biggest contributing factor. “We’ve got to find a way out of these declines,” says Hall, “but in the interim we have an opportunity within cities to support and bolster bee habitat.”

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