Hof, C., Rahbek, C. & Araújo, M.B.

The question of whether closely related species share similar ecological requirements has attracted increasing attention,
because of its importance for understanding global diversity gradients and the impacts of climate change on species
distributions. In fact, the assumption that related species are also ecologically similar has often been made, although the
prevalence of such a phylogenetic signal in ecological niches remains heavily debated. Here, we provide a global analysis
of phylogenetic niche relatedness for the world’s amphibians. In particular, we assess which proportion of the variance in
the realised climatic niches is explained on higher taxonomic levels, and whether the climatic niches of species within a
given taxonomic group are more similar than between taxonomic groups. We found evidence for phylogenetic signals in
realised climatic niches although the strength of the signal varied among amphibian orders and across biogeographical
regions. To our knowledge, this is the first study providing a comprehensive analysis of the phylogenetic signal in species
climatic niches for an entire clade across the world. Even though our results do not provide a strong test of the niche
conservatism hypothesis, they question the alternative hypothesis that niches evolve independently of phylogenetic
influences.