Texas A&M team is helping save monarchs from highway deaths
Add Axios as your preferred source to
see more of our stories on Google.
Illustration: Brendan Lynch/Axios
Two Texas A&M University scientists are tackling one of the biggest threats to monarch butterflies on their fall migration through Texas: death by car.
Why it matters: Monarchs are important pollinators that support our food system and a healthy environment for wildlife and humans, but the eastern migratory population has declined by about 80% since the mid-1990s, per the U.S. Fish and Wildlife Service.
- The service is considering listing monarchs as a threatened species.
Context: The butterflies head through Texas on their way to Mexico for the winter each year.
Threat level: At least 6% of deaths are due to collisions on Texas roads, Robert Coulson, professor in the Department of Entomology, tells Axios.
- Road mortality is "the most significant issue associated with monarch return through Texas," he says. "There's no question about that."
What they did: Coulson and James Tracy, postdoctoral research associate, began tracking monarch migration along Texas highways in 2016 with funding from the Texas Comptroller's Office. Their ongoing work is funded by TxDOT, Coulson says.
- Coulson and Tracy drove thousands of miles collecting butterfly remains and recording their location.
What they found: The resulting map shows how wind patterns and Texas' geography, like hills and canyons, lead the monarchs to areas where they collide with vehicles most often.
State of play: Based on those findings, the team is testing flight diverters, or mesh panels installed near highways that encourage the monarchs to fly higher in vehicle collision hot spots.
- Coulson and team are currently evaluating the diverters at two test sites: In West Texas along Interstate 10 near Ozona, and at the Lavaca Bay Causeway near Victoria.
Stunning stat: Early results at the Ozona site show that the diverters cut monarch deaths in half during the fall migration.
What they're saying: Texas is "absolutely fundamental" to monarchs' spring and fall migration, Coulson says, as the butterflies seek out trees to rest in.
- At a park in Ozona, Coulson says you can see thousands of monarchs in the trees overnight. They take flight again when the sun comes up.
- "It's a magnificent sight to see this blaze of orange hit the sky," he says.
What's next: Funding for the research ends next August. By then, Coulson says the team plans to release an evaluation of the diverters that could determine whether more are installed across Texas.
The bottom line: Lessons learned about protecting monarchs can also help bees and other essential insects, since the species affects broader pollinator health, Coulson says.