The importance of phylogeny and habitat factors in explaining gametophytic character states in European Amblystegiaceae

Abstract

A redundancy analysis (RDA), with subsequent forward selection and variance partitioning, was performed to evaluate whether gametophytic character state variation in European members of the Amblystegiaceae is best explained by their generic position, or their habitat. Depending on whether traditional generic concepts or those resulting from Hedenäs' recent revisions of taxa within the family are used, the explanatory parameters explain 69% and 79%, respectively, of the total character state variation. The generic position, reflecting the phylogenetic component, is as important as, or more important than the habitat factors studied, depending on whether the traditional or Hedenäs' generic concepts are used. Hedenäs' generic classification explains ca 50% more of the gametophytic character state variation within the family than the traditional one. This underlines the importance of the classification that is used when the influence of the phylogenetic history on various traits is evaluated. In the RDA, the most important environmental gradients found relate to habitat wetness and spring influence. It is proposed that niche conservatism and phylogenetic time lags are responsible for the large proportions of the variation that are explained by generic position plus habitat jointly, and generic position only, respectively. Convergent evolution may explain the complex of adaptations for transport of water from the lower wet portions of the plants to the upper parts that are exposed to the air in many Amblystegiaceae.