ProjetMode de dispersion et d’établissement du roseau commun (Phragmites australis)
Biological invasions are currently considered by the scientific community as the second global cause of biodiversity loss. Two main components to understand this success are on one hand to determine the functional and life history traits of species that favor their invading potential (invasiveness) and on the other hand to explain the biotic and abiotic conditions of local environment that make it vulnerable to invaders (invasibility). The rapid invasion of the introduced subspecies of common reed (Phragmites australis) in the northeast of North America is a spectacular example of plant invasion. A program of prevention and control of this grass requires adequate knowledge of the biological and ecological characteristics. It is crucial to define its dispersal strategies in order to protect sites not yet colonized or to target sites sensitive to the colonization. Although common reed can spread both by vegetative propagation and sexual reproduction, the contribution of each of these modes is unknown along roadside ditches, the main habitat of the plant in Quebec. Similarly, although common reed is abundant along highway right-of-ways, some sections are particularly resistant to invasion, including in areas highly colonized by the plant. Therefore, my research interest is, on one hand, to evaluate the relative participation of the reproductive modes in the establishment of new populations and, on the other hand, to identify the nature of the environmental conditions hostile to this exotic grass. The overall aim of my PhD is to define the spread strategies of this invasive species. The findings will have practical and applied benefits by allowing managers, ministries and municipalities to develop new effective methods to fight the common reed.