Non-parametric methods reveal non-linear functional trait variation of lichens along environmental and fire age gradients
Nelson PR, McCune B, Roland C, Stehn S. 2015. Non-parametric methods reveal non-linear functional trait variation of lichens along environmental and fire age gradients. Journal of Vegetation Science. 26(5):848–865
Popular methods to analyse community–trait–environment relationships constrain community patterns by trait and environment relationships. What if some traits are strongly associated with community composition but unrelated to environmental variables and vice versa? We take a different approach, unconstrained by this assumption using non-parametric methods. We applied this technique to lichen (fungal/algal and/or cyanobacterial symbioses) communities across environmental and fire age gradients by measuring richness and cover of four important functional traits: energy generation (type of photosynthetic symbiont), water relations (inferred from growth form), dispersal capability (from vegetative propagules) and microsite specificity (measured by substrate affinity).