Idaho State University Ecologists Studying Ways to Improve Vegetation Along Idaho’s Roads and Highways

Recently, Joshua Grinath, assistant professor of community and global change ecology, and his students wrapped up the first growing season at three experimental sites along Interstate 15 in Eastern Idaho. At the sites, which represent three types of sagebrush steppe ecosystems in the area, Grinath and his team of researchers have been working with the Idaho Transportation Department to find out how to make the land more hospitable to native plants and less so for invasive weeds, have increased fire resistance, and be an attractive habitat for pollinators like bees and butterflies. The research team is testing how different combinations of mowing, herbicide treatments, and seed applications can improve the roadsides for native plant survival. In September, the team was awarded additional funding to test how adding certain types of bacteria, fungi, and micronutrients to the soil may improve restoration.

"There are roughly 28,000 miles of road managed by the Idaho Transportation Department. Consequently, that’s a lot of roadsides to manage,” Grinath said. “Roadside management is most commonly focused on a single issue, such as erosion control, but other challenges may be able to be addressed simultaneously. Considering these issues simultaneously will help ITD save taxpayers money and address urgent land management concerns."

The project is the topic of a thesis that’ll be authored by Erika Stewart, a biology master’s student from Boise, Idaho. Stewart is handling the day-to-day management including collecting and analyzing data, writing reports and grants, mentoring undergraduate students, and more. 

“I am passionate about land management - particularly how to combat invasive species and increase the prevalence of native species,” said Stewart. “This project was a perfect fit for my interests, as it is addressing concerns about invasive species, fire risk, and pollinator habitat, and has the potential to achieve results that may impact current land management practices for years to come.”

“Erika is doing an amazing job and is demonstrating true leadership on this project,” Grinath said. 

 The research is primarily funded through a grant from the Idaho Transportation Department. Additional funds are being supplied by ISU’s College of Science and Engineering and Office for Research. Grinath and Stewart will present their research findings and recommendations to ITD in late 2023. 

"By evaluating multiple native plant restoration methods together with multiple management goals, we hope to identify best practices that increase the efficiency of roadside management. Land managers face multiple challenges, from controlling weeds to providing habitat for declining species such as pollinators, and we hope that the results of our research will help ITD and other management organizations to overcome these collective challenges."

For more information on the ISU’s Department of Biological Sciences, visit isu.edu/biology. 

Prospective students can schedule a campus tour at isu.edu/visit.