A direct comparison of ecological theories for predicting the
relationship between plant traits and growth
Abstract
Despite long-standing theory for classifying plant ecological
strategies, limited data directly links organismal traits to whole-plant
growth. We compared trait-growth relationships based on three prominent
theories: growth analysis, Grime’s CSR triangle, and the leaf economics
spectrum (LES). Under these schemes, growth is hypothesized to be
predicted by traits related to biomass investments, leaf structure or
gas exchange, respectively. In phylogenetic analyses of 30 diverse
milkweeds (Asclepias spp.) and 21 morphological and ecophysiological
traits, growth rate varied 50-fold and was best predicted by growth
analysis and CSR traits, as well as total leaf area and plant height.
Despite two LES traits correlating with growth, they contradicted
predictions and leaf traits did not scale with root and stem
characteristics. Thus, although combining leaf traits and whole-plant
allocation best predicts growth, when destructive measures are not
feasible, we suggest total leaf area and plant height, or
easy-to-measure traits associated with the CSR classification.