Responses of invasive alien plant Erigeron canadensis L. to nutrient availability and fluctuations

Global change will not only affect environmental conditions but also temporal environmental fluctuations. Fluctuations in resources contribute to the successful invasion of alien plant species; however, the impact of resource fluctuations on the biomass allocation to aboveground and belowground parts of invasive plants remains largely unclear. Using the invasive plant Erigeron canadensis L. as a target species, we established four different nutrient additions (constant low, constant high, multiple pulses, and single pulse) to investigate how invasive alien plants respond to changes in resource availability in the environment. Results showed that aboveground biomass, belowground biomass, chlorophyll content, and specific leaf area of E. canadensis were significantly increased under high nutrient conditions compared to low nutrient conditions, although the root-shoot ratio decreased significantly. In all high nutrient treatments, the temporal pattern of nutrient supply also affected plant biomass production, root-shoot ratio, and specific leaf area. Particularly, single pulse treatment greatly inhibited aboveground biomass and promoted belowground biomass, while multiple pulse treatment exhibited a slight tendency to promote total biomass of the invasive plants and significantly increase specific leaf area. Our study shows that environmental resource fluctuation can change the growth strategy of invasive plants and thus affect their performance, but nutrient availability fluctuations do not significantly promote the growth of invasive plants.