A matter of scale and traits: a comment on ‘On the need for phylogenetic “corrections” in functional trait-based approaches’ by de Bello et al. (2015)

Abstract

A recent paper by de Bello et al. (2015) reviewed the problems of imposing phylogenetic corrections in functional ecology irrespective of the research question. Although we agree with them, we do believe that the scenarios where phylogenetic corrections would be unnecessary deserve a specific look on two aspects: scale and traits. Our intention is to show that the decision to use phylogenetic corrections is not that straightforward and that a more integrative approach yields a bigger picture of processes shaping communities. Firstly, patterns at local scales may depend on regional-scale processes, which are described by biogeographical processes and thus phylogeny. Secondly, de Bello et al. suggested that if traits are conserved, phylogeny may be used as a proxy for unmeasured traits; however, the importance of phylogenetic signals of traits must be taken into account when these vary across a spectrum rather than presenting a dichotomy between conserved and convergent traits. Additionally, there may be overdispersed and underdispersed patterns of traits within the same species pool, further reinforcing that using phylogeny for unmeasured traits might lead to inaccurate predictions. Depending on the question, as discussed by de Bello et al. (2015), evaluating changes in functional trait values along environmental gradients does not preclude the use of phylogenetic corrections. However, previous studies have demonstrated that combined approaches are beneficial in reaching a more accurate precise picture of processes shaping communities species responses.