Abstract
Residence time, i.e. the time of introduction of alien species to the region, is an important factor co-determining their current distribution. In modern invasions on the time scale of centuries (neophytes), the longer the alien species are present in the territory the higher their chance (i) to pass successfully through the stage of casual occurrence and become naturalized, and (ii) to become more distributed and invade over a larger range.
In Europe, the effect of residence time is still obvious in archaeophytes, that invaded several millenia ago. Comparison of Czech Republic and Britain indicates that the invasion by archaeophytes in both regions started immediately with the beginning of agriculture.