Pest management in future climates: Warming reduces physical weed management effectiveness

Area of Science:

• Ecology
• Agronomy
• Climate Change Biology

Background:

• Climate change impacts weed phenology and management efficacy.
• Physical weed control methods, like mowing, are understudied in warming contexts.
• Invasive species pose significant ecological and economic threats.

Purpose of the Study:

• To investigate the effects of elevated temperatures on invasive musk thistle (Carduus nutans) growth and survival.
• To evaluate the effectiveness of different mowing timings as a control strategy for musk thistle under ambient and warming conditions.
• To project population growth rates of musk thistle under various climate change and mowing scenarios.

Main Methods:

• Field experiment with musk thistle grown at ambient and elevated temperatures.
• Mowing treatments varied in timing relative to plant phenology, compared to an unmowed control.
• Demographic models used to project population growth rates under different warming/mowing scenarios.

Main Results:

• Warmed thistles exhibited increased survival, earlier flowering, greater height, and more capitula production compared to ambient conditions.
• Mowing provided smaller proportional reductions in plant height and capitulum production under warming.
• Late-season mowing remained the most effective strategy under both ambient and warming conditions.
• Warming significantly increased projected population growth rates for musk thistle across all mowing treatments.

Conclusions:

• Elevated temperatures enhance invasive musk thistle performance, diminishing the efficacy of mowing.
• Supplemental management, such as increased mowing frequency or chemical control, may be necessary for effective weed management in a warming climate.
• Future research should assess management practices under experimental warming and monitor weed responses to inform adaptive strategies.