Functional traits of 7 spp of tropical palms in Costa Rica
Functional traits influence life history strategies. Leaf economics spectrum theory shows the existence of two opposing life history strategies: species with an “acquisitive” strategy that exploit high-resource environments, and species with a “conservative” strategy thriving in low-resource conditions. We analyze interspecific variation in nine functional traits related to biomass allocation and tissue quality (tissue density, dry mass fraction -dmf-, slenderness ratio, carbon content, diameter, height, leaf area, and root:shoot ratios based on biomass and carbon content) in seven species of palms from three forest strata (understory, subcanopy, and canopy). We found two groups of correlated traits. The first one included traits related to palm size (i.e., height, carbon content and leaf area), whereas the second group included traits associated to biomass distribution (i.e., dmf and tissue density). We selected four principal components explaining 87.48% of the variation. The first one (40.32%) was influenced by variables related to palm size (e.g., diameter, total carbon content, leaf area, and height), whereas the second one (16.89%) had a similar contribution of tissue density and dmf. Palms segregated in the multidimensional space defined by these two components: understory species were more related to biomass distribution traits (tissue density and dmf), whereas subcanopy and canopy species were associated to palm size traits (diameter, stem height, leaf area, total carbon content). Knowing the role of functional traits in palms is relevant to understand how different resource allocation strategies regulate plant growth in contrasting light environments. Since palms are one of the most abundant life forms in tropical forests, exploring functional trait variation within this group could significantly advance our understanding of plant adaptation to environmental gradients.