Widely naturalized species are not more promiscuous in the use of different nitrogen forms, but benefit more from inorganic nitrogen

Abstract

Nitrogen (N) is an essential mineral nutrient necessary for plant growth and has been considered a crucial factor influencing invasion success. Former studies mainly focused on responses of alien plants to different levels of N availability. However, in natural soils, N comes in different forms. Few experimental studies have explored responses of naturalized alien species to different N forms, and whether such responses are related to their naturalization success globally. We selected 22 common herbaceous species native to Germany that have all become naturalized and thus been introduced elsewhere in the world. We grew these species under six different N conditions that differed in the amount or form of N, and assessed their growth performance in a greenhouse experiment. We found that plants produced more biomass when grown under high N levels than under low N levels, and when N was provided in inorganic form than when provided in organic form. 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 study shows that although the widely naturalized alien 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.

Responses of invasive and native plants to different forms and availability of phosphorus

“…Geng and He (2021) indicated that changes in nitrate to ammonium ratio differentially influence the mortality rate of invasive and native species. Additionally, Zeng et al (2021) found that certain alien plants can benefit greatly from inorganic N. On the other hand, invasive plants can grow more efficiently when supplied with organic P compared with inorganic P (Yang et al, 2020). The higher phenotypic plasticity of invasive species relative to native species may provide a competitive advantage in using different nutrient forms (i.e., occupy a broader range of environments) although no studies have explicitly tested this possibility.…”