Fine‐scale Phylogeography of Coastal Fishes in the South China Sea: Possible Roles of Biological Traits and Geography

Aim Although the underlying biotic and abiotic factors of phylogeographic patterns is an important topic in biogeography, they remain largely unexplored in marine fishes. We empirically investigated the effects of several biological traits on phylogeographic patterns of selected marine fishes. We predict that overall similarity in these traits correlates with similarity in phylogeographic patterns among species, and that genetic diversity and demographic stability are associated with these traits, as well as the local (paleo)environment. Location Five localities in the South China Sea (SCS). Taxon Thirteen species of coastal marine fishes. Methods Phylogeographic Concordance Factors (PCFs) based on mitochondrial DNA sequences were tested for correlation with similarity based on distribution range, depth of occurrence, habitat preference, salinity tolerance and fecundity among the subset of the focal species. The relationship between phylogeographic patterns and these traits was also qualitatively examined. Bayesian model averaging was used to test the association between these traits and the genetic diversity estimates. Results Pairwise PCFs of five species across all localities were correlated with pairwise biological similarity, with depth and distribution ranges contributing most to the biological similarity. Nucleotide diversity of Indo-west Pacific species tended to be greater than that of circumtropical species. Populations showing signs of demographic expansions were concentrated in three localities. A novel concordant population break across six focal species and other marine organisms coincided with the dispersal barrier previously suggested by biophysical dispersal modelling. Main conclusions Abiotic factors were dominant in controlling phylogeographic patterns, with possible contributions from biotic factors. Depth and distribution ranges, or other eco-physiological traits underlying these, might have influenced the phylogeographic patterns of several species, presumably coupled with historical vicariance. The geography of local populations relative to the shallow continental shelf may explain the heterogeneous demography. Historical vicariance and contemporary ocean currents have contributed to the concordant population break.