Global invasive plant study conducted at Montana Tech reveals evolution can make invaders stronger competitors

Some of the study’s core contributing authors during their visit to Montana. From left: Dávid Nagy, Kevin Kozic, Christoph Rosche, Robert Pal, and Julian Selke.

Montana Technological University professor Dr. Robert Pal is among the core contributing authors of a major international study published in Nature Communications, bringing together more than 100 researchers from around the world.

Dr. Robert Pal works with native plants in the Montana Tech greenhouse.

In the study, entitled “Rapid and repeated evolution of increased competitive ability in a global invader,” researchers investigated Erigeron canadensis, commonly known as Canadian horseweed, using 100 native and 165 non-native populations collected across much of the Northern Hemisphere.

The research found that non-native populations were significantly more competitive against other plant species than populations from the plant’s native range, even under drought conditions.

The research included a large-scale greenhouse experiment conducted on Montana Tech’s campus in Butte. Researchers grew thousands of plants under different competition and watering conditions to determine how the invasive species responds to both other plants and environmental stress.

“I am especially proud of this study because it grew out of a collaboration with my former Ph.D. student, David Nagy from Hungary, and his colleagues at Martin Luther University Halle- Wittenberg,” Pal said. “During my 2023–2024 sabbatical, we were able to build that collaboration into a truly international effort, bringing together more than 100 researchers from around the world to address a fundamental question in invasion ecology.”

Researchers found non-native populations had 19.2% higher competitive ability overall than native populations. Genetic analysis also indicated that increased competitive ability evolved independently in multiple groups, suggesting invasive plants can rapidly adapt after being introduced to new environments.

The findings could help scientists better understand why some invasive species become increasingly successful over time and how they may continue to affect native plant communities as environmental conditions change. The results could also inform more effective invasive-species control methods and ecological restoration strategies.