The distribution of functional trait values offers a potentially powerful window into the ecological, evolutionary, and historical factors underlying biodiversity patterns across the globe. Here, we integrate data from five key life-history traits—seed mass, leaf mass per area (LMA), wood density, plant height, and growth form—with phylogeny and geographic occurrence records to interrogate the patterns of functional diversity within Ericales taxa inhabiting the New World. The integration of phylogeny into the biogeography of functional trait diversity helps to illustrate the phylogenetic scale at which ecological strategies vary.
Results/Conclusions
We find that species inhabiting colder environments exhibit a phylogenetically-conserved suite of traits we term the ‘polar trait syndrome.’ This syndrome is characterized by low seed mass, shorter stature, and a tendency for lower wood density/ more herbaceous and shrubby growth forms. The trait values that a species possesses correlate well with the most extreme latitude at which it occurs. The traits associated with this polar syndrome are strikingly similar to those traits predicted for pioneer species in the successional literature—namely, low seed mass, wood density, LMA, and shorter stature.
We hypothesize that traits associated with being a pioneer species have served as preadaptations to entering cold environments. Cold environments are more recent in the history of angiosperms, have undergone greater frequency of large-scale disturbances, and represent an environment with a shorter growing season and in which quick responses to changing resources would be advantageous, which might explain why a common set of traits is observed for cold-adapted Ericales and pioneer taxa.