Data from: Which ecological factors influence the level of intraspecific diversity within post-glacial fishes? A case study using Coregonus and Salvelinus

While it is likely that ecological context is important, the factors that
facilitate and maintain variable levels of intraspecific diversity in
Salmonidae fishes across environments remain unclear. Using a
meta-analysis of sympatric ecotype assemblages from two salmonid genera –
Salvelinus and Coregonus – we evaluated the importance of ecological
factors determining the number of sympatric ecotypes (i.e., two to seven)
and the level of trait divergence between them. We found that ecotype
diversity increased with lake depth and surface area in both Coregonus and
Salvelinus. Further, diversity in Coregonus increased with latitude, while
the number of ecotypes in Salvelinus assemblages was linked to climatic
seasonality. In comparing the two genera we found elevated divergence in
traits related to ontogeny (i.e., age and body shape) in Salvelinus and
gill raker count in Coregonus. Trait divergence in life history traits
(i.e., age and body length) in Salvelinus increased with seasonality,
whereas contrasting relationships of latitude to body length and gill
rakers were found in Coregonus. We also found similar levels of divergence
in trait variance in the two genera, suggesting that among-ecotype
differences in phenotypic variability are not more common in one genus
than the other. Overall, ecosystem characteristics, including lake
location, climate, and morphometry, are clearly important for where these
genera have diversified, but the variables that are most closely
associated with intraspecific diversity differ between the two genera
studied, and depend on whether diversity is quantified using number of
ecotypes or trait divergence.