Calling Phragmites australis the common reed really undersells its pervasiveness. The up to 6-meter-tall wetland grass has been vexingly ubiquitous in North America since a European subspecies was introduced in the 1800s and spread widely and aggressively. In fact, the plant is so tenacious in wetland habitats that it chokes out native North American lineage of the species (sometimes considered a separate species dubbed P. americanus) as well as many other native plants, lowering floral species richness by almost three fold and pushing out specialist marsh animals, including many threatened and endangered species.
Despite decades of research, one enduring mystery is why the European lineage is so invasive in North America, when its close kin have existed on the continent for millennia without taking over wetlands. Genetic studies have revealed tantalizing clues, including ploidy levels in the European lineage ranging from 2 to 12x and higher. But genetic investigations into ...