Herbaria provide long-term data crucial for tracing changes over a long period of time. The vast number of herbaria collections together with increasing digitization and the posibility for sequencing DNA from preserved plant material, make herbaria valuable resources for understanding ecological and evolutionary species responses to main drivers of global change e.g. industrialization causing increased pollution, increasing loss of habitat and changes in land use as well as climate change, and finally global trade and transport resulting in an increasing number of invasive species world‐wide (see also Using herbaria to study global change).
This project aims to understand the invasion success of Japanese knotweed (Reynoutria japonica, R. sachalinensis and R. x bohemica, in the Polygonaceae family). We are using herbarium specimens to reconstruct the colonization history of Japanese knotweed in Europe and North America and test for genetic changes associated with its invasion.