Amount Awarded: $24,996
Plant invasions lead to environmental and economic problems worldwide. Despite these negative impacts, they also present exciting opportunities for evolutionary research, especially to uncover the genetic basis of rapid adaptation in action. The model system for this study, ice plant (Carpobrotus edulis), is native to South Africa but invasive in three Mediterranean climate zones: California, Australia, and the Mediterranean Basin. Here, we propose to investigate the invasion history of ice plant by generating sequence data for historic and modern herbarium specimens collected across the native range and the invasive ranges on all three continents and spanning through late 18th century to present. By analyzing genomic data from these abundant collections covering parallel time series, we will test: (a) if continuous gene flow from the native range or neighbouring populations increased the genetic diversity in the invasive ranges, (b) if rapid local adaptation led to the invasive success of ice plant; and (c) if similar evolutionary processes enabled rapid expansions in California, Australia and the Mediterranean Basin during these independent invasion events. Together, these results will shed light to the evolutionary mechanisms that enable expansion of a highly invasive plant and test the generality of these patterns over a multi-continental scale.