When do non-native species become invasive? A methodological approach.
The invasive behavior of non-native species in a new habitat depends on the invasiveness of the species itself on the one hand and on the invasibility of the ecosystems on the other hand. We discuss the mutual relations between the traits that foster the invasiveness of selected woody species and the invasibility of the concerned ecosystems in the light of the leading theories on ecological invasions. As examples we use selected tree species (Robinia pseudoacacia, Ailanthus altissima, Prunus serotina, Cinnamomum glandulifera), shrub species (Prunus laurocerasus, Laurus nobilis, Elaeagnus pungens) and a palm species (Trachycarpus fortunei) that are already considered to be invasive in the southern foothills of the Swiss Alps.