Roadsides mowed less often and sprayed more carefully held 45 per cent more pollinators, according to a new Canadian study.

Researchers at the University of Ottawa compared rural roadsides around the city that are managed differently. Lanark County mows twice a year and only spot-treats invasive weeds.

Neighbouring Ottawa and Leeds and Grenville County mow up to four times a year and spray herbicide more widely. The side-by-side setting let the team isolate the effect of management alone.

Sites with the low-intensity approach had far more bees and flower flies, and 23 per cent more species of both, the study found.

“What surprised us wasn’t that management mattered; it was how much difference two modest changes made,” said lead researcher Jessica Forrest.

The findings were published in the journal Insect Conservation and Diversity. Roadsides add up to a huge area of land across the country.

The study suggests that small changes in maintenance could turn millions of kilometres of roadside into better wildlife habitat.