A multi-species experiment in their native range indicates pre-adaptation of invasive alien plant species

P>To understand prerequisites of biological invasions, it is imperative to know whether species have traits that pre-adapt them to become invasive elsewhere. However, few experimental studies have explicitly tested this by comparing traits between invasive and noninvasive species in their native range instead of in the nonnative range. We used native plant material of 14 European congeneric pairs of herbaceous species that were all introduced to North America, and of which one species per pair is invasive. In our germination and common garden experiment with and without fertilizer addition, the invasive species germinated faster, produced more biomass and had a higher proportion of flowering plants than the noninvasive congeners. Our results indicate that species traits, which lead to a high plant performance in the native range, can confer pre-adaptation to become invasive. We suggest that such traits may be especially relevant for use in risk-assessment protocols before introduction elsewhere.