Leprieur F. auteur aut IRD Albouy C. auteur aut IRD De Bortoli Julien auteur aut IRD Cowman P. F. auteur aut IRD Bellwood D. R. auteur aut IRD Mouillot D. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The evolutionary dissimilarity between communities (phylogenetic beta diversity PBD) has been increasingly explored by ecologists and biogeographers to assess the relative roles of ecological and evolutionary processes in structuring natural communities. Among PBD measures, the PhyloSor and UniFrac indices have been widely used to assess the level of turnover of lineages over geographical and environmental gradients. However, these indices can be considered as 'broad-sense' measures of phylogenetic turnover as they incorporate different aspects of differences in evolutionary history between communities that may be attributable to phylogenetic diversity gradients. In the present study, we extend an additive partitioning framework proposed for compositional beta diversity to PBD. Specifically, we decomposed the PhyloSor and UniFrac indices into two separate components accounting for 'true' phylogenetic turnover and phylogenetic diversity gradients, respectively. We illustrated the relevance of this framework using simple theoretical and archetypal examples, as well as an empirical study based on coral reef fish communities. Overall, our results suggest that using PhyloSor and UniFrac may greatly over-estimate the level of spatial turnover of lineages if the two compared communities show contrasting levels of phylogenetic diversity. We therefore recommend that future studies use the 'true' phylogenetic turnover component of these indices when the studied communities encompass a large phylogenetic diversity gradient. specialized 020 082 7 8 e42760 2012 1932-6203 https://www.documentation.ird.fr/hor/PAR00009374 10.1371/journal.pone.0042760 1932-6203 [F B010057235] https://www.documentation.ird.fr/hor/PAR00009374 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-09/010057235.pdf IRD - Base Horizon / Pleins textes 2012-11-09 2017-10-03 PAR00009374 fre