Identifying subspecies of Phragmites australis in the Coastal Bend of Texas

Phragmites australis is a tall and growing grass that has five subspecies, two of which may be native to North America: P. australis subsp.americanus found on the east coast, and P. australis subsp. berlandieri found on the Gulf coast.  The introduced European subspecies, P. australis subsp. australis, has invasively spread along the east coast of North America, where it has interrupted marsh ecosystem function and decimated native species. However, while populations in eastern North America have been characterized, few studies have documented the subspecies that regularly occur on the Gulf coast.  Therefore, we have begun a rapid genetic assessment of Phragmites subspecies in the Coastal Bend of Texas along with a companion study of morphological characteristics. Because morphological differences among the subspecies can be subtle and the introduced species is invasive, identification of these populations is critical for proper management of these populations. We are using a restriction fragment length polymorphism (RFLP) assessment based on amplifying two regions of the chloroplast genome with PCR and digesting the fragments with restriction enzymes, which produces diagnostic banding patterns for each of the three subspecies known in North America. We are now analyzing the results from our assay and will be completed in early August.  With this assessment, agencies managing these Phragmites populations will know whether the sites have native or invasive subspecies and, therefore, take appropriate action.