Nitrogen (N) has been considered a crucial factor influencing invasion success. Many studies have assessed responses of alien plants to different N availabilities. However, in natural soils, N comes in different forms. Few studies have explored yet whether responses of alien species to different N forms are related to their naturalization success globally. 

We selected 22 common herbaceous species native to Germany that have all become naturalized elsewhere in the world. We grew them under six different N conditions that differed in the availability or form of N, and assessed their growth performance.

We found that neither biomass production nor promiscuity to different N forms was related to naturalization success of the species. However, the biomass response to inorganic N, relative to organic N, was stronger for the widely naturalized species than for the less widely naturalized ones.

Our comparative multi-species study shows that although the widely naturalized species were not more promiscuous than the less widely naturalized species, they took more advantage of the inorganic-N forms. This indicates that naturalization success might be partly driven by a species’ ability to take advantage of increased inorganic N levels.

We did a greenhouse experiment, in which we selected 22 common herbaceous species native to Germany that have all become naturalized elsewhere in the world. We grew them under six different N conditions that differed in the availability or form of N, and assessed their growth performance.

NA represents the missing values. If you have any questions, please write Dr. Yanjie Liu (ecoyj.liu@gmail.com).