“Even in the middle of the city, bees were using these small patches of habitat.”
Having green spaces in urban areas can lift people’s moods, improve their health and boost their quality of life. Such patches of greenery also benefit other creatures, bees and other pollinators among them.
By converting empty lots into green spaces, we can create little islands of biodiversity within cities that can help embattled insects like bees that are increasingly threatened in their natural habitats, according to a team of researchers at Ohio State University in the United States.
The researchers found that small experimental plots in the midst of connected green spaces home to flowering native plants “created conditions most conducive to the conservation of native bees and predatory wasps.”
As most cities have plenty of vacant lots, converting them could have a real benefit for biodiversity and the conservation of insects like bees, which have fallen on hard times across much of the planet as a result of habitat fragmentation and the wanton use of pesticides in agricultural areas.
The scientists evaluated various “greening” strategies that could support symbiotic relationships between plants and insects within urban areas in order to boost biodiversity. Experimental lots they examined included a dense grass lawn left unmowed, a lawn with various flowering grasses, a prairie-type area with tall native grasses, and a prairie-type lot with a mixture of flowering native grasses and plants.
The researchers found that turf grass widely used for greening areas in cities can support some insect populations. However, the benefits of these pale beside other types of green spaces that are more hospitable to pollinators because of the presence of flowering native plants.
“Even in the middle of the city, bees were using these small patches of habitat,” said Mary Gardiner, professor of entomology at Ohio State University who was a key member of the research team. “This is one of the first times a paper has demonstrated that native bees responded with a reproductive benefit from the establishment of native plantings within a city.”
Earlier research has shown that having a diversity of various flowering plants in one area is important for pollinators like bees and bumblebees. The new research, meanwhile, has demonstrated that greening cities in specific ways can aid in the reintroduction of pollinators like bees and wasps in urban areas to help create or maintain local biodiversity.
“This work has shown that some proportion of the bees and wasp community will respond to larger patches of greenspace being reinstituted in the landscape, even if they are not the natural habitat that was there pre-development,” Gardiner said. “And I think that’s really exciting.”