Aridity drives coordinated trait shifts but not decreased trait variance across the geographic range of eight Australian trees

Large intraspecific functional trait variation strongly impacts many aspects of communities and ecosystems, and is the medium upon which evolution works. Yet intraspecific trait variation is inconsistent and hard to predict across traits, species, and locations.
We measured within-species variation in leaf mass per area (LMA), leaf dry matter content (LDMC), branch wood density (WD), and allocation to stem area vs. leaf area in branches (branch Huber value, HV) across the aridity range of seven Australian eucalypts and a co-occuring Acacia species to explore how traits and their variances change with aridity.
Within-species, we found consistent increases in LMA, LDMC and WD, and HV with increasing aridity, resulting in consistent trait coordination across leaves and branches. However, this coordination only emerged across sites with large climate differences.  Unlike trait means, patterns of trait variance with aridity were mixed across populations and species. Only LDMC showed c...