Revegetation for reinvasion resistance following Phragmites control

Background

Invasive Phragmites (Phragmites australis subsp. australis) is a tall, aggressive wetland grass that forms vast, monotypic stands in many parts of the US. It degrades important fish and wildlife habitat, reduces recreational opportunities, and poses risks like poor visibility along roadsides. 

In Minnesota, there has been a landscape-scale effort to prevent large monocultures and their impacts from taking hold. As of 2024, roughly 25% of documented invasive Phragmites populations in the state have been eliminated. Following removal, land managers should restore treated sites to prevent them from becoming reinvaded. Revegetation is a critical phase of management that has not yet been integrated into Minnesota’s invasive Phragmites response efforts. Research from other parts of North America shows revegetation can make habitats resistant to Phragmites reinvasion.

Research questions

• In sites formerly invaded by Phragmites, what alternative species and seed mixes support invasion resistance for multiple years? 
• What attributes of seeded species and mixes maximize resistance?
• How do the viability and abundance of invasive Phragmites seeds influence reinvasion?

Practical implications

This work is needed to help preserve the gains achieved by removal efforts in Minnesota and beyond, and contribute to a sustainable strategy for protecting ecosystems from severe impacts of invasive Phragmites over time. Results of this study will support the development of guidelines for revegetation following invasive Phragmites removal. The findings will help local, state, federal, and international managers determine when and how to include revegetation in their adaptive management toolkits.

Findings

This project began in February 2025 and is in progress for the next several years. Please check back at a later time for updates.

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