What’s good for pollinators is also good for utility companies

Power companies dedicate significant resources to cleaning up overgrown plants and debris around power lines. These areas are known as electrical rights-of-way, and anything that obstructs access to these areas can threaten power outages, affect public safety, and make it harder for utility crews to perform necessary maintenance and repairs.

A new study shows that proper vegetation management benefits not only utilities, but also pollinating insects. In the largest study of its kind, covering the greatest number of sites and species, researchers from the Florida Museum of Natural History studied 18 rights-of-way managed by Duke Energy. They found that sites maintained on a specific schedule that kept woody vegetation to a minimum had a greater quantity and diversity of flowering plants and pollinating insects.

The research is published in the journal PLOS ONE.

“It’s a win-win,” said Chase Kimmel, an insect conservation biologist at the museum and first author of the study. “It’s exciting to see that the goals of promoting pollinator habitat align with how Duke Energy wants to manage these lands.”

Many of Florida’s pollinating insects thrive in early successional habitats, created by occasional disturbances, such as wildfire. Historically, Florida’s landscape was a patchwork of different habitat types. As fields turned to forests, the resulting timber provided kindling for fires that started naturally, often from lightning strikes. The fire cleared the understory and opened the canopy, allowing sunlight to reach the newly bare forest floor and creating a perfect environment for wildflowers.

Human development, however, has disrupted this cycle. Wildfires are quickly extinguished, and many areas are too close to homes and businesses for prescribed burns to be carried out safely.

“It’s becoming increasingly rare to find early successional habitats,” said Ivone de Bem Oliveira, a postdoctoral researcher at the Florida Museum and co-author of the study. “So we can mimic that environment under power lines.”

Utility crews use mechanical and chemical interventions to maintain a safe corridor for energy transmission. Such maintenance activities can serve as a proxy for the wildfires that have historically created successive habitats in Florida. This combination of management tools allows for easier and safer access to power lines for repairs, improves transmission reliability, reduces long-term vegetation management costs, and ensures habitat and energy consumer safety.

Methods include mowing, selective application of herbicides to kill woody vegetation, and using equipment to trim trees that become too tall or thick. This is especially important in Florida, where weather events such as severe thunderstorms and hurricanes can cause power outages for short periods of time.

Although Duke Energy prefers to keep its rights-of-way free of coarse woody debris, construction sites sometimes fall behind schedule. Curious about how this affected plant and insect diversity, the research team sorted its study areas by ranking sites based on measurements of bare soil and coarse woody debris.

“In higher intensity management areas, you can easily walk under the power line, while in medium intensity areas, you can find shrubs and various raspberry bushes, making it impossible to walk in a straight line. In low intensity areas, it is even difficult to cross the area,” Kimmel explains.

Researchers define management intensity not by how often a site is managed, but by the type of habitat that results. Some rights-of-way were considered high intensity even though they were managed only once a year or every other year.

At these sites, the researchers set up a total of 2,376 bowl traps to collect pollinating insects. These bowls, commonly used in insect diversity studies, are filled with soapy water and are often bright blue, yellow and white. To insects, these colorful bowl traps look like flowers.

The researchers collected 11,361 flower-visiting insects, representing 33 families. Nearly half were bees and a quarter were beetles. Flies, wasps, butterflies and moths made up most of the remainder.

Intensively managed sites had the greatest abundance and diversity of these insects. These sites also had the greatest number and variety of flowering plants.

“In some of these environments, you often see a rich herbaceous understory because of regular disturbance,” said Jaret Daniels, lead author of the study and curator at the museum’s McGuire Center for Lepidoptera and Biodiversity. “That also helps support rare plant communities.”

“The public might think it’s better to just sit back and let nature do its thing,” Kimmel said. “But that’s not always the case.”

To foster a rich and abundant pollinator community, the authors recommend intensive right-of-way management. This does not mean, as the name suggests, constant mowing or indiscriminate herbicide applications, but rather a combination of strategies that target specific plants with the goal of maintaining successional habitat.

Across much of North America, utility rights-of-way connect and traverse all types of landscapes, from urban to rural. There are 180 million power lines in the United States and 5.5 million miles of power lines dedicated to them. Using these areas as pollinator habitat could be a game changer for conservation.

Long corridors can also facilitate the movement of migratory species. They can help foraging insects travel long distances in search of food, which can potentially promote significant pollination activity in nearby agricultural and conservation lands.