Data from: Evolution of the leaf economics spectrum in herbs: evidence from environmental divergences in leaf physiology across Helianthus (Asteraceae)

The leaf economics spectrum (LES) describes a major axis of plant
functional trait variation worldwide, defining suites of leaf traits
aligned with resource-acquisitive to resource-conservative ecological
strategies. The LES has been interpreted to arise from leaf-level
trade-offs among ecophysiological traits common to all plants. However, it
has been suggested that the defining leaf-level trade-offs of the LES may
not hold within specific functional groups (e.g., herbs) nor within many
groups of closely-related species, which challenges the usefulness of the
LES paradigm across evolutionary scales. Here we examine the evolution of
the LES across 28 species of the diverse herbaceous genus Helianthus (the
sunflowers), which occupies a wide range of habitats and climate variation
across North America. Using a phylogenetic comparative approach, we find
repeated evolution of more resource-acquisitive LES strategies in cooler,
drier, and more fertile environments. We also find macroevolutionary
correlations among LES traits that recapitulate aspects of the global LES,
but with one major difference: leaf mass per area is uncorrelated with
leaf lifespan. This indicates that whole-plant processes likely drive
variation in leaf lifespan across Helianthus, rather than leaf-level
trade-offs. These results suggest that LES patterns do not reflect
universal physiological trade-offs at small evolutionary scales.