Invasive Phragmites is a tall, densely growing grass that can take over large areas, push out native vegetation, and reduce habitat quality for wildlife. Research at MAISRC is focused on determining its current distribution in Minnesota, evaluating its capacity for further spread, and developing management protocols.

About Phragmites

What it is 

Phragmites australis, also known as common reed, is a tall, perennial grass. It is found in wetlands, riparian areas, shorelines, and other wet areas.

Both native and non-native genotypes of Phragmites are present in Minnesota. For this reason it has been dubbed a “cryptic” invader. Without coordinated effort to distinguish and map native and non-native forms, the true distribution of invasive Phragmites in the state cannot be determined. This gap poses two risks: lack of action in response to new invasions or indiscriminate treatment that damages the native subspecies.

What it affects

Invasive Phragmites is an ecosystem engineer that benefits from human-caused disturbances on the landscape. Invasive populations in North America have been shown lower plant diversity, changes to food webs, and reduce diversity and abundance of invertebrates, fish, and waterbirds.

What it looks like

Invasive Phragmites grows taller and denser than its native counterpart. Several morphological characteristics such as stem color and leaf sheaths have been used to distinguish native and non-native forms. MAISRC researchers are testing the reliability of these characteristics by comparing identifications performed by experts and non-experts with conclusive genetic testing.

Where it's found

Phragmites australis has a global distribution, being found on all continents except Antarctica. The lineage that is invasive in North America — from the Atlantic coast westward to Minnesota and beyond — is native to Europe. This form has spread across North America over the past 150 years, almost entirely displacing native Phragmites in regions where it has long been established.

Distribution of non-native Phragmites in Minnesota is not currently well-understood; MAISRC research is working to address this.

How it spreads

Invasive Phragmites can spread both sexually (by seed) and asexually (clonally). When populations are producing large amounts of viable seed, spread across the landscape is more rapid and control is more difficult and expensive. The extent of sexual reproduction in Minnesota is unknown. Researchers are working to answer this by quantifying seed production and performing viability tests.

Phragmites research at MAISRC


Current efforts

MAISRC researchers are mapping the current distribution of European strains of Phragmites in Minnesota, determining its capacity for further spread, and developing management protocols for responding to different invasion scenarios.

Current projects

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