Irvington’s O’Hara Nature Center was part of a statewide study designed to help New York create pollinator pathways throughout the state’s highway system. The ultimate goal is to replace grass median strips with maintenance-free native plant gardens, supporting wildlife habitats while eliminating the need for mowing grass.
O’Hara was one of 40 research sites across New York that worked with the Cornell Waste Management Institute and the New York State Department of Transportation (DOT) to create in-depth reports on the activity of pollinating wildlife around their native plantings, based on observations they documented from April through November 2020.
The study analyzed the pollinator activity at various ecozones in New York State, according to O’Hara’s educational director, C.J. Reilly. The research sites ranged from western New York to eastern Long Island. “They’ll all have a different soil profile — different degrees of sand, to clay, to loam,” Reilly explained. “We’re more of a glacier deposit area, where there’s not a lot of topsoil, and the topsoil we have is close to bedrock. Long Island is going to have different soil structure, so they’ll be able to cater to different plant species.”
The study looked at what was growing at each research site, and which pollinators were relying on native plants as a food source. This information will allow DOT to create customized topsoil/seed mixtures that will grow on highway medians in specific areas of the state, and attract the greatest variety of wildlife.
O’Hara’s 11 demonstration gardens yielded a wealth of information, according to Reilly.
“There were a total of 2,404 observations, and 150 species were identified in an area just under an acre,” he said. “It’s cool to think of the biodiversity such a small area can have.”
The O’Hara report included photos taken at set times in the morning and afternoon in order to document the pollinating fauna that visited native plants. The photos were uploaded to the iNaturalist app.
The report also includes an analysis of soil samples and growing conditions on the O’Hara property. The planting sites all had little to no soil disturbance in the past 30 years, so they presented an accurate snapshot of soil conditions encountered in southern Westchester.
“Residents can see the most common five pollinators in a given month, and within those time periods they can see them change — what are the most prolific flowers at that time, and the pollinators that are pollinating those plants,” Reilly explained. “And then it breaks it down by part shade to full shade to sun, and into fenced and unfenced areas.”
While seed catalogs and labels on plants provide gardeners with an idea of which flora are “deer resistant,” the report offers more specific evidence of those left intact, even without protective fencing.
Overall, the five most pollinated plants were blunt mountain mint, Joe Pye weed, brown-eyed Susan, heartleaf aster, and white snakeroot. The five most observed pollinators were the common eastern bumblebee, the western honey bee, the ligated furrow bee, the brown-belted bumblebee, and the eastern tiger swallowtail butterfly. The cast of characters varied from month to month depending on what was in bloom.
By studying the photographic evidence, O’Reilly made specific identifications of who was pollinating which plants, and when. “We discovered in 2020 that we have a vulnerable species,” he said, referring to the golden northern bumblebee. “Its population and habitat loss is extreme enough to warrant its being called a vulnerable species.” The ground-nesting golden northern prefers large open areas, and only pollinates at midday. “Their distribution is not what it used to be,” Reilly said. “And they’re hard to find — but we found it.”
The report includes photos that show the variations among pollinators. For example, there were six different bumblebee species observed in the study, and 15 different species of butterfly.
Reilly said homeowners can use the report to plan their own pollinator gardens and get an idea of what sort of wildlife will likely visit their plants. They can also upload photos of their own pollinator gardens onto the iNaturalist app to become part of the story of the larger area.
Even though the work on the Cornell study has been completed, it’s just the beginning of Reilly’s ambitions for the O’Hara Nature Center. He hopes to leverage the results of the study on a larger scale, introducing new planting areas in the Irvington Woods adjacent to the center. His plans to undertake such a project with the help of volunteers from the community and school district.
“We’re looking at succession planting for 2022 and 2023… expanding into these mixed-use areas in Irvington Woods Park,” he said. “And we’re probably going to be helping insect species.”
For example, thanks to the study, he now knows that O’Hara has a population of “very healthy two-spotted bumblebee. They tend to live in woodland areas near wetlands. So by giving them more protected areas, we’ll be giving them more habitat.”