“…, but this classification has not yet been justified. Interactions of exotic trees and native fauna are of vital interest for ecologists in large-scale experiments of the establishment of animal-plant relationships (see, e.g., Rejmá nek, 2000;Richardson et al, 2000;Davis, 2003;Richardson and Rejmá nek, 2004;Roques et al, 2006;Adams et al, 2009;Bertheau et al, 2009). As already mentioned, the definitions of Richardson et al (2000) barely fit Norway Spruce at lower elevations in central Europe because the geographic continuity encompasses the natural and artificial distributions.…”