Strategies for a successful plant invasion: the reproduction of Phragmites australis in northeastern North America

1. Knowing the relative contribution of vegetative propagation and sexual reproduction to the dispersal and establishment of exotic plants is crucial for devising efficient control strategies. This is particularly true for the common reed (Phragmites australis), one of the most invasive species in North America. 2. For the first time we combined in situ field observations and genetic evidence, based on two genotyping techniques, i.e., microsatellite markers (SSR) and genotyping-by-sequencing (GBS), to determine the propagation strategies of this invader at its northern distribution limit in North America, and especially in roadside ditches. 3. Field observations revealed that, in a region where the common reed is already abundant, both seeds and plant fragments contributed to the establishment of new populations. Newly established individuals originated mostly (84%) from seeds rather than fragments, but a larger proportion of individuals originating from fragments survived the second ye...