Premise—Many studies have assessed the various responses of alien plants to changes in overall nutrient or different nitrogen (N) availabilities. However, in natural soils, nutrients are present as different chemical elements (e.g., N and phosphorus [P]) and forms (e.g., inorganic and organic). Few studies have explored yet whether invasive and native species differ in their responses to varying P availability and forms.

Key results—We found that invasive species did not show an overall higher biomass production than that of native species under varied P conditions. However, the biomass response to organic P was, relative to the response to inorganic P, stronger for the invasive species than that for the native species. This coincided with the pattern that invasive species mainly allocated biomass to the root system under organic P conditions.

Conclusions—Our study indicates that while invasive species were not more promiscuous than native species were, they took great advantage of the organic-P forms. Therefore, the invasion risk of alien species may increase in habitats with more organic P sources.

We grew five taxonomical related pairs of common herbaceous invasive and native species alone or in competition under six different conditions of P availability or forms, and assessed their growth performance.