A direct comparison of ecological theories for predicting the relationship between plant traits and growth

Despite long-standing theory for classifying plant ecological strategies, limited data directly links organismal traits to whole-plant growth rates. We compared trait-growth relationships based on three prominent theories: growth analysis, Grime’s competitive-stress tolerant-ruderal (CSR) triangle, and the leaf economics spectrum (LES). Under these schemes, growth is hypothesized to be predicted by traits related to relative biomass investment, leaf structure or gas exchange, respectively. We also considered traits not included in these theories, but that might provide potential alternative best predictors of growth. In phylogenetic analyses of 30 diverse milkweeds (Asclepias spp.) and 21 morphological and physiological traits, growth rate (total biomass produced per day) varied 50-fold and was best predicted by biomass allocation to leaves (as predicted by growth analysis) and the CSR traits of leaf size and leaf dry matter content. Total leaf area and plant height were also excellent ..., ,