Functional diversity plays a role in driving β-diversity: Or does it?

Patrick and Brown (2018) suggest that functional diversity of the species pool has an important role in generating β-diversity. Using a combination of path analysis and model selection, they ostensibly provide support for this hypothesis; however, they neglected to put theory and modeling into proper ecological and statistical context. Here, I present a re-analysis of their data. I conclude that the drivers of β-diversity are variable, with functional diversity typically having a reduced, if any, role compared to consistently stronger roles played by γ-diversity or environmental variation on structuring β-diversity.