Abstract
Functional traits are defined such as traits which affect individual
fitness. I argue that the use of the term “functional trait”
complicates the progress of the field of trait ecology because all
traits are potentially linked to fitness. Obviating the potential link
of all traits with fitness is related to dismissing (i) the integration
of the phenotype, (ii) the spatio-temporal variation of environmental
pressures and (iii) the genotype by environment interaction effect on
the phenotype. These conceptual gaps could explain the weak predictive
power of many functional ecology studies. I develop here some of the
reasons why we should consider that all traits are related to fitness
-advocating simultaneously for a change in terminology.