Functional traits capture fundamental tradeoffs that determine species’ ecological roles. The tradeoff between the number of seeds produced and the size of each individual seed provides a clear-cut example. Large seeds provision robust seedlings able to succeed where competition is intense and resources are scarce, but can only be produced in relatively small numbers. In contrast, tiny seeds fail where competition is intense, but can be produced in copious numbers that increase the chance of dispersing to ephemeral sites with few competitors and high resource availability. Thus, seed size is an easily measured functional trait that is likely to provide insight into the relative dispersal and competitive abilities of different plant species. Other key functional traits are believed to provide similar insights with respect to light capture (specific leaf area or leaf area per unit leaf dry mass), photosynthesis (leaf nutrient concentrations), defense against pests (wood density, leaf toughness) and other aspects of competitive ability (plant size). Collectively, these and other key functional traits help to determine the ecological roles of different plant species.
To learn about the ForestGEO vision for trait-based research, download a PDF of the Functional Traits Working Group report, which describes how the classification of terrestrial plant species by continuously varying functional traits promises solutions to important ecological questions at community, ecosystem, biome, and global scales.