On a September afternoon on the University of Florida campus, a bee lifts off from a sun-warmed patch of pavement and starts searching. Around it are parking lots, a large, buzzing mower clipping a turf lawn and ornamental hedges.
Somewhere in Gainesville, there is a native flower that evolved alongside it. The bee has to find it first.
Pollinators are already facing a long list of threats. Corey Callaghan, an assistant professor in the Department of Wildlife Ecology and Conservation at UF/IFAS, said those threats rarely act alone.
“I think climate change, urbanization, pollution, habitat loss, which is kind of coupled with urbanization, I think all of those all play a very kind of, like, multiplicative, meaning,” said Callaghan. “ They all kind of combine together in unique and nuanced and hard-to-understand ways to kind of, like, to have a negative impact on pollinators.” Callaghan and his graduate student, Marina Marquis, published a study last month in Royal Society Open Science discovering that pollinators in urban areas with little natural spaces throughout the eastern United States have seasons that start and end later in the year. Of the 52 species analyzed, 19 from three orders showed phenological, or normal behavioral, shifts.
While a slight shift in activity may seem inconsequential, pollinators have a delicate relationship with their pollinator-dependent plants. In the spring, they emerge from hibernation or migration to feed on early-blooming plants. In summer, activity peaks, and “the long days of summer provide pollinators the maximum time to forage for nectar,” according to the Smithsonian Gardens.
However, during the fall, pollinators feed on late-blooming plants to prepare for hibernation.The researchers found that pollinators began buzzing about three weeks later in the most human-modified landscapes compared to those in remote or rural settings.
The issue: Their dependent plants didn’t get the message. This relationship is at risk for a disconnect.
“A potential problem is if the resources that pollinators need, like nectar and plants, are blooming at different times, when the pollinators are not able to persist in those environments, then that can create what's called this phenological mismatch,” Callaghan said.
When the resources they need aren’t there, Callaghan said it can make it difficult for pollinators to reproduce and survive.
The study names Atlanta as an example of an urban area impacted by the shift. Atlanta Botanical Garden’s Gulf Coast Program Manager Kelly Coles says that the disconnect from pollinators starting activity later in the season is just part of the problem;plants are struggling as well.
As a part of the Greater Atlanta Pollinator Partnership (GAPP), The Atlanta Botanical Garden has created a plant pollinator program. The team conducts urban habitat restoration by installing pollinator gardens across the city and provides educational resources for residents to learn how to create their own gardens.
“There is some building evidence that the impacts of global climate change are impacting pollinator and plant relationships because plants are blooming earlier than they used to, or just kind of out of sync with when the pollinators are coming out,” Coles said. “That can cause things like a decline in seed set and just a decline in populations of the rare plants that I mostly work with.”
Seed set refers to the process where a fertilized plant develops a viable seed. A decline in seed set means plants are not becoming pollinated, so while some may bloom, they aren't producing viable seeds, ultimately leading to population decline. Coles suggests that because of the disconnect, city planners for developing cities, like Gainesville, need to plant native plants that provide food to pollinators year-round. When landscape designers are selecting plants, she said it is important “to make sure that species are being selected that bloom in early spring and in summer.”
Currently, the Alachua Conservation Trust is working to protect and create habitats in urban areas across north-central Florida. In 2024, ACT partnered with Bee City Gainesville to plant a native pollinator garden at Bubbe's Secret Garden, a one-acre community park a few blocks north of University Avenue..
ACT also acquires properties to protect them from development. Their most recent acquisition was a 66-acre conservation easement in Levy County earlier this month.
Coles also stressed that while city planners need to provide spaces for pollinators, city residents also have the ability to support their populations.
“I think while it's incredibly important for city planners to be thinking that way and landscape designers, it's just as important to be thinking about the small renter or small homeowner.” she said. “We can do a lot in that way,”
Small home gardens can provide a connection between larger city-designated areas, creating a wildlife corridor. Even a single passion vine can help, Coles said, “that's more important now than ever.”
Callaghan says the next step in their research isto look at pollinators and their host plant interactions.
“Some pollinators only reproduce on a given plant, right, like a single species,” he said “So one of the things that we're interested in next, these ideas of interactions and how interactions persist in urban environments and how they change the function of urbanization and green space use,”
For more information on how to start your own pollinator-friendly garden, visit sites such as the Florida Native Plant Society or your local plant nursery.