1. Numerous studies have highlighted the role of nutrient availability and fluctuations therein for invasion success of alien plants. Others also highlighted the role of herbivores in invasion success. However, how herbivory and the level and fluctuations in nutrient availability interact in driving alien plant invasion into native communities remains largely unexplored.

2. We grew eight invasive alien species as target species in pot-mesocosms with five different synthetic native communities in a three-factorial design with two levels of nutrient availability (low vs high), two levels of nutrient fluctuation (constant vs pulsed) and two levels of herbivory (with vs without).

3. The relative biomass production of the alien target plants decreased in response to an increase in nutrient availability, and increased in response to the presence of herbivores. Furthermore, herbivory could interact with changes in nutrient availability and nutrient fluctuations to affect the dominance of the alien target species (a marginally significant interaction; 90% CIs: [0.005, 0.176]).

4. Synthesis: Our multispecies experiment indicates that herbivory could mediate the interactive effect of nutrient enrichment and variability in nutrient supply on invasion of alien plants into native communities. Therefore, we recommend that studies testing the fluctuating resources hypothesis should also consider interactive effect of other trophic levels.

To test the individual effects of nutrient availability, nutrient fluctuations, herbivory, and their interactions on alien plant invasion into resident communities, we grew eight invasive alien species as target species in pot-mesocosms with five different synthetic native communities, each consisting of three grassland species. Then, we exposed the plants to eight combinations of two nutrient availability (low vs high), two nutrient-fluctuation (constant vs pulsed) and two herbivory (with vs without) treatments. After about three months, we harvested the aboveground of the target species and the native community of each pot.

The unit of biomass is gram. If the alien target and native plants died, or the pots had accidentally been treated with the wrong nutrient solution, their values were recorded as NA in the table.

If you have any questions, please write Dr. Yanjie Liu (ecoyj.liu@gmail.com).