Influence of elevation and habitat disturbance on the functional diversity of ferns and lycophytes

Background: The loss of functional keystone species may lead to the loss of key functions in the ecosystem. Few studies so far have addressed the functionality of specific morphological traits of ferns.Aims: Evaluate the functional diversity and how habitat degradation affected the functional diversity of fern assemblages.Methods: Along an elevational gradient in central Veracruz, Mexico, we recorded allferns and lycophytes species in plots placed in old-growth, degraded and secondary forest and quantified 15 morphological traits. We calculated Functional Diversity (FD) and Functional Beta Diversity (FBet).Results: We found a positive correlation between species richness and FD, with maximum FD in the species-rich plots located in humid montane forests at intermediate elevations, which were also functionally the most distinct in the analysis of FBet. There was no consistent relationship of FD and FBet to habitat degradation.Conclusions: Functional diversity is not generally related to habitat degradation. The low values of FD in degraded and secondary forest stands at mid-elevations indicated a loss of functions with degradation, whereas FD values in ecosystems of the lower sites indicated functional redundancy that helps to maintain the functions even when there is a loss of species richness.