Abstract
Species distributions along an environmental gradient are often not symmetric but skewed towards one end of the gradient. Various explanations for this skewness have been proposed but the patterns of niche asymmetry along extensive environmental gradients have been rarely explored.
In this study, we tested three predictions of asymmetric abiotic stress limitation (AASL) hypothesis that predicts a steeper decrease in the probability of occurrence towards the more stressful end of a plant distributional range.