Protecting Monarch Migration Across Texas Highways

In this episode of ‘The Stream by AASHTO’ podcast, Darlene Goehl (above) – research engineer and research group lead at Texas A&M University’s Transportation Institute or TTI – discusses the joint work of TTI and the Texas Department of Transportation in building Monarch Flight Diverters or MFDs – a series of tall, mesh barriers placed along busy roads that motivate the butterflies to fly above the roadway, well above vehicles traveling on the highway below.

[Above photo by TTI]

This podcast series is part of the AASHTO Environmental Management technical service program operated by the American Association of State Highway and Transportation Officials. It explores a wide array of environmental topics that affect state departments of transportation and the infrastructure programs they oversee.

In this episode, Goehl explains that researchers recently noted sharp declines in Monarch populations, specifically during their migration periods in the fall.

[Editor’s note: In November 2024, The Leaflet by AASHTO newsletter published a two-part series about TxDOT’s Monarch protection efforts. Part One of that series can be accessed by clicking here and Part Two by clicking here.]

In some years, researchers found that nearly 3 percent of the Monarch’s fall migratory population were lost after being struck by vehicles traveling on roads; this number represents about half of the population decline in a given year.

Goehl discusses the importance of Monarch butterflies to the ecology and cultural symbology of the southern U.S. and northern Mexico, the role transportation in protecting them, and how TTI identifies “hot spots” for Monarch roadkill. From there, Goehl explains the implementation and feasibility of MFDs in Texas and how the project will fare into the future. To listen to the full podcast, click here.