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New IDOT Mowing Approach to Help Protect Monarch Butterfly, Pollinator Populations in Illinois

May 18, 2017


  • Conservation Stories

Press Release by the Illinois Department of Transportation, May 15, 2017, available on the website.

To help revive the shrinking populations of the monarch butterfly and other pollinators, the Illinois Department of Transportation is adjusting its mowing routine along state highways this spring and summer. The approach, part of IDOT’s overall effort to encourage green and sustainable practices in all its programs and projects, will help to re-establish types of plants that are food sources for bees, butterflies and other insects that are native to Illinois.

“As one of the largest land owners in the state, IDOT appreciates its tremendous responsibility to act as stewards of the environment,” said Illinois Transportation Secretary Randy Blankenhorn. “This simple change in our maintenance obligations will have little impact on the traveling public, but will give a big assist to Mother Nature at no cost to the state.”

Although their numbers are on the decline, pollinators play a vital role in agriculture and the state’s ecosystem by fertilizing and aiding in reproduction of flowers, fruits, vegetables and seeds. The official state insect of Illinois since 1975, the monarch butterfly is at risk of being declared endangered, with a population that’s declined by 80 percent the last 10 years.

Starting this month, IDOT will only mow 15 feet of right of way beyond the edge of the roadway. Exceptions will be made in certain areas to preserve sightlines for motorists and to prevent the spread of invasive plant species.

Prior to this initiative, mowing widths varied by location. By reducing the amount of land being mowed, IDOT hopes to encourage the growth of critical plant species, such as milkweed, the only food source for monarch caterpillars. In the coming months, IDOT will be monitoring roadsides to determine if the approach is working. In recent months, IDOT has taken other measures to restore native habitat along state highways, including a prairie restoration project on U.S. 45 near Champaign.


The MJV is excited to share this great news for pollinators in Illinois! For additional information, see recent research on the opportunities for monarch habitat along roadsides, resources for rights-of-ways, and the Mowing: Best Practices for Monarchs handout.


The Monarch Joint Venture is a national partnership of federal and state agencies, non-governmental organizations, and academic programs working together to conserve the monarch butterfly migration. The content in this article does not necessarily reflect the positions of all Monarch Joint Venture partners. Header photo by Candy Sarikonda.