Responses of an invasive plant Alternanthera philoxeroides to cadmium, nutrient availability and water temperature

Introduced plant invasion, heavy metal pollution, eutrophication , and rising water temperatures collectively pose complex and severe environmental problems in freshwater ecosystems . Further clarification is needed on how invasive plants respond to these combined environmental stresses. We investigated the response of Alternanthera philoxeroides , a common invasive plant species in China, to two levels of cadmium concentration (0 or 1 mg L −1 Cd 2+ ), crossed with two levels of nutrient availability (0 or 10 mL L −1 concentrated nutrient solution) and two levels of water temperature treatments (25 or 35 ℃). The presence of cadmium significantly inhibited the overall growth of A. philoxeroides , while the high nutrient level increased its growth. Temperature did not affect overall growth but primarily influenced branch number. There were statistically significant interactions between nutrient availability and temperature for several of our measurements; however, such significant interactions were not observed in the other two-way interactions. Overall, the high temperature enhanced the benefits derived from the high nutrient availability on the performance of A. philoxeroides . The three-way interaction only affected root-shoot ratio. The findings suggest that the high water temperature may exacerbate outbreaks of this invasive plant, particularly in freshwater habitats with high nutrient levels. • We examined the effects of cadmium, nutrients and water temperature on an invasive plant Alternanthera philoxeroides . • The main effect of cadmium and nutrients on A. philoxeroides is more significant than that of water temperature. • High water temperature enhanced the benefits derived from high nutrient levels on the performance of A. philoxeroides . • High water temperature may exacerbate outbreaks of A. philoxeroides in eutrophic freshwater habitats.