Cladal divergence in fungal Ophiognomonia (Gnomoniaceae: Diaporthales) shows evidence of climatic niche vicariance.

We used the globally widespread genus Ophiognomonia as a model system to investigate climatic niche patterns in fungi, characterizing the climatic profiles of 28 species with seven temperature and seven precipitation variables. Using a novel version of Spatial Evolutionary and Ecological Vicariance Analysis (SEEVA), designed to deal with continuous and correlated variables, we examined well-sampled phyletic splits of a multi-gene phylogeny. We evaluated the degree to which phyletic divergence has been associated with climatic niche divergence between sister lineages, permitting elucidation of climatic associations in evolutionary context. From the 14 inter-correlated climatic variables, we extracted four principal axes, accounting for 93.2% of the climatic variation, with axes broadly labelled as: polarity, tropicality, winter mildness and aridity. We also analysed the two single variables maximum monthly temperature and precipitation. We detected climatic associations that were compatible with both niche conservatism and niche divergence within the phylogeny, and different cladistic bifurcations associated with different climatic splits. As might have been anticipated, geographic separation (or lack thereof) of phylogenetic splits was correlated with climate niche divergence (or conservation). This elaborated SEEVA method provides a visual and statistically solid basis for characterizing climatic niche divergence that should prove useful for elucidation of many other taxonomic groups. [ABSTRACT FROM AUTHOR]