Department of Invasion Ecology has been involved in pan-European projects dealing with alien and invasive species (e.g., ALARM, www.alarmproject.net, DAISIE, www.europe-aliens.org) and cooperated on the European database of alien species, established by the latter project. Long term research interests include theoretical aspects of invasion process and classification of alien species, macroecological patterns of biological invasions, determinants of habitat/region/ecosystem invasibility and the role of species traits in invasions. Special attention is paid to determining the relative roles of factors affecting invasions (e.g. propagule pressure, residence time, climate, species attributes). Major invasive species of the Czech flora are addressed in detailed case studies. Field research is combined with experimental approaches, information from databases (including a working database of the flora of the Czech Republic) and historical data.