Control effort exacerbates invasive-species problem

Area of Science:

• Ecology
• Conservation Biology
• Environmental Management

Background:

• Invasive species management often involves aggressive tactics like herbicide use.
• Balancing invader control with native species protection is a significant challenge for ecosystem managers.
• The impact of control methods on native biota is a critical, often overlooked, consideration.

Purpose of the Study:

• To evaluate the long-term effects of aggressive management (herbicide application) on native grassland forbs.
• To determine if herbicide use for invasive species control negatively impacts native plant populations.
• To assess the indirect effects of herbicide application on native-invader dynamics.

Main Methods:

• A 16-year study in a grassland ecosystem.
• Investigated the effects of one-time herbicide application on native forbs.
• Manipulated grazing exclusion alongside herbicide treatment.

Main Results:

• One-time herbicide application led to the extreme rarity of two native forbs for the entire 16-year study.
• Other native forbs also became rare, particularly when grazing was excluded.
• Evidence suggests the dominant invader increased in abundance following reductions in native forb populations.

Conclusions:

• Herbicide applications for invasive species control can be detrimental to native plant communities, even when applied once.
• Management decisions must carefully weigh the potential damage to native species against the benefits of invader control.
• The findings serve as a cautionary example for invasive species management in ecosystems where native species are present.