Increased snow facilitates plant invasion in mixedgrass prairie

Area of Science:

• Ecology
• Global Change Biology
• Invasive Species Management

Background:

• Global change impacts plant invasion, but precipitation effects are understudied.
• Invasive species thrive in wet, nitrogen-rich areas of mixedgrass prairies.
• Predicted climate changes may increase precipitation and nitrogen deposition, potentially worsening invasions.

Purpose of the Study:

• To investigate the interactive effects of altered precipitation (snow, irrigation) and nitrogen addition on invasive species establishment and growth.
• To assess the potential for climate change to exacerbate plant invasion in North American mixedgrass prairies.

Main Methods:

• Experimental seeding of six invasive species into mixedgrass prairie plots.
• Factorial application of increased snow, summer irrigation, and nitrogen addition.
• Measurement of invasive species biomass, density, and recruitment responses.
• Comparison of invasive species responses to those of resident native species.

Main Results:

• Snow addition dramatically increased the biomass of invasive forbs like Centaurea diffusa, Gypsophila paniculata, and Linaria dalmatica.
• Summer irrigation further enhanced G. paniculata density under snow addition.
• Nitrogen addition increased L. dalmatica density and biomass, particularly with added snow.
• Invasive species density increases mirrored biomass gains, suggesting enhanced recruitment.
• Resident native species showed no significant response to snow addition.

Conclusions:

• Increased snowfall or snowfall variability may significantly promote forb invasion in mixedgrass prairies.
• Altered precipitation regimes, coupled with nitrogen deposition, can create favorable conditions for invasive species.
• These findings highlight the vulnerability of mixedgrass prairies to climate change-induced invasions.