Role of enemy release and hybridization in the invasiveness of Impatiens balfourii and I. glandulifera.

Comparative studies with taxonomically and geographically paired alien species that exhibit different degrees of success in their invasions may help to identify the factors that determine invasiveness. Examples of such species in Europe include the noninvasive Impatiens balfourii and invasive I. glandulifera.

The ability of seeds to float with water currents contributes to the invasion success of Impatiens balfourii and I. glandulifera.

Two alien species in Europe, Impatiens glandulifera and I. balfourii, are closely related, have similar growth rates and reproductive capacities, and are very attractive to pollinators. Nevertheless, only I.