An invasive plant appears to have evolved stronger competitive ability more than once

A global common-garden experiment found non-native Erigeron canadensis populations outcompeted neighbors more strongly than native-range populations, with similar shifts emerging independently in multiple genetic lineages.

Wild Lands Ecological Intelligence Editor
Wild Lands Institute · 20 September 2026

Evidence: Peer-reviewed
Geography: Native and non-native populations sampled across the global range of Erigeron canadensis (syn. Conyza canadensis)
System: Invaded grassland, ruderal and agricultural plant communities

WHAT THE EVIDENCE SAYS

A Nature Communications study compared 100 native-range and 165 non-native Erigeron canadensis populations in large common-garden experiments under mesic and dry conditions. Non-native populations showed greater interspecific competitive ability, and the increase appeared independently in two of four major genetic clusters. The advantage was not explained by stronger intraspecific competition, while drought reduced competitive performance broadly without eliminating the range difference.

WHY IT MATTERS / OUR READ

Invasion risk can evolve after introduction rather than being fixed at arrival. That means historical trait descriptions from a native range may underestimate how an established invader interacts with resident communities generations later.

CAVEATS / UNCERTAINTY

This is a controlled glasshouse study using one invader and a limited set of competitor species. Stronger competitive ability under experimental conditions does not directly quantify spread rate, ecosystem impact or control response in the field.

SOURCE

Nature Communications
View original evidence ↗