Any feature of an organism, expressed in the phenotype and measurable at the individual level, which has demonstrable links to the organism's function (Lavorel et al. 1997; Violle et al. 2007). As such, a functional trait determines the organism's response to external abiotic or biotic factors (Response trait), and/or its effects on ecosystem properties or benefits or detriments derived from such properties (Effect trait). In plants, functional traits include morphological, ecophysiological, biochemical and regeneration traits. In animals, these traits include e.g. body size, litter size, age of sexual maturity, nesting habitat, time of activity.