Invasion biology has addressed or even solved several key questions about biological invasions, but the central issue of long-term effects of invasive species has remained critically unexplored. Several case studies exist about long-term population dynamics of invasive species and their impacts, but a general synthesis or understanding is currently lacking. This knowledge gap is critical, as long-term shifts in invader population densities and traits are likely and may have large consequences of ecological and economic interest. This project aims to narrow the knowledge gap.