Whole-genome processes interact with ecology and geography in shaping plant invasiveness: a global population-level study of the genus Phragmites

This project employs a novel framework to address multiple factors affecting plant invasiveness using the model grass species Phragmites australis. Using an extant collection of hundreds of populations from all over the globe, we will measure geographically structured variation in the cytological make-up (genome copy number and nuclear DNA amount) and in a common garden experiment the ecological traits (growth, reproduction, enemy attack, competitive ability) of the populations and assess how these interact to determine invasiveness. We hypothesise that cytological and ecological traits directly affect invasiveness and are co-shaped by their invasion potential over evolutionary history in the population’s geographic origin and by environmental variation in the introduced range. In addition, cytology and geography also affect invasiveness indirectly by influencing ecological traits. Disentangling these complex issues, backed-up by existing knowledge of populations’ genetic make-up will provide novel insights into mechanisms of invasion at the population level. Our aim is to identify factors that confer global invasion success of an invasive grass Phragmites australis, assess the interactions between ecological, cytological, genetic and geographical determinants of invasion at the population level, and separate the direct and indirect effects of factors.