A native plant competitor mediates the impact of above- and belowground damage on an invasive tree

摘要: Plant competition may mediate the impacts of herbivory on invasive plant species through effects growth and defense. This predictably depend whether occurs above or below ground relative competitive ability. We simulated potential impact above- belowground damage by biocontrol agents a woody invader (Chinese tallow tree, Triadica sebifera) artificial herbivory, with without native grass, little bluestem (Schizachyrium scoparium). measured two defense responses quantifying constitutive induced extrafloral nectar production tolerance (root shoot biomass regrowth). examined genetic variation in across (China) (United States) populations. Without competition, aboveground had greater than performance, whereas impacted similarly. Whole to was negatively associated grass competitors indicating tradeoffs ability tolerate vs. compete. Competition reduced investment defensive (EFN) production. Aboveground inhibited rather EFN while did not found some support for evolution increased hypothesis plants as United States were larger China more plastic their response biotic stressors (they altered root ratios dependent treatments). Our results indicate that habitat type presence be determinant feeding mode suggest integrated pest management strategies including dynamics recipient communities should incorporated into biological control agent evaluation at earlier stages.