Scientists Work to Identify and Thwart the Spread of Invasive Phragmites in Florida

Photo Credit:  Lyn GettysThe “common” reed (Phragmites), as its name would imply, is one of the most widely distributed flowering plants across the globe. Phragmites exists on every single continent except Antarctica and, in the past century, has begun to cause major problems in North America. Although native varieties of the plant exist in North America, introductions of plants from Europe and Asia have created a virtual hodgepodge of common reed that even the most seasoned botanist can’t differentiate between.

The state of Florida, already touting the title of the “Invasive State”, is no stranger to Phragmites and the problems associated with its invasive varieties. The state currently has two known representatives of Phragmites: a native Gulf Coast variety, and a Eurasian variety, both of which can demonstrate nuisance behavior. Reports of Phragmites increasing its local range in Florida have raised questions about the current status of the native variety, and the potential that the invasive is on the move across the Sunshine State. Dean Williams of Texas Christian University and others took up the call for action and began a quest to determine the extent of Phragmites, invasive or native, across Florida and throughout the southeastern United States. Furthermore, the group took on the task of trying to identify morphological differences between the varieties which may aid managers in reducing impacts from the invasive varieties.

The group left no wetland unturned, sampling leaf tissue and DNA from various sites in Florida, Alabama, Mississippi, Louisiana, Georgia, and South Carolina. Stem density, stem height, stem texture, and color were all observed in an attempt to determine if the varieties could, in fact, be identified with the naked eye.

Data collected by Williams et al.

Data collected by Williams et al.

The team of researchers found very little morphological difference among the native Gulf variety with most plants having a smooth stem that is red at the base. The Eurasian variety, however, had noticeably ribbed stems, a green exposed stem at the base, and a slightly dull color overall. As one might expect, stem density of the Eurasian variety was significantly higher than the Gulf Coast plants. Gulf Coast plants were typically taller yet were less dense than the invasive variety. Fortunately, the team did not identify any invasive Eurasian strain of Phragmites in the state of Florida, observing only the Gulf Coast strain. The closest site identified as containing the Eurasian variety was 68km from the Florida border in Georgia.

The group of researchers hope that the morphological traits identified in the Eurasian variety are easily distinguishable for managers in the field.  Although the invasive variety is thought to be more adept to spread and colonization, Florida currently has no known stand of the Eurasian variety.  The researchers speculate that this is likely due to the Eurasian variety being less favorable of the unique Florida environment and having a difficulty establishing with the already established Gulf Coast strain.

To read the article in its entirety, click HERE.

UPDATE:  Recent research has identified Eurasian Phraigmites through leaf tissue DNA analysis in the State of Florida.  “Early detection and rapid response to an exotic Phragmites population in Florida” (Overholt et al), will be featured in the fall edition of Aquatics Magazine.  Stay tuned for more updates.

For more from the Journal of Aquatic Plant Management, click Here.

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