A link between plant traits and abundance: evidence from coastal California woody plants

Abstract

A number of recent studies have demonstrated that plant traits play a crucial role in determining the success or failure of species in a given environment. However, whether traits play a role in determining species' abundance and rarity among the co-occurring species within a community remains an unresolved question.2. To address this, we analysed the abundance of California coastal woody plant species at landscape and local scales in relation to 11 leaf, wood and seed traits.3. At the landscape scale, we found no significant relationship between traits and abundance. In contrast, at the local scale we found significant relationships between abundance and four traits: specific leaf area (SLA), height, lumen fraction and wood density. For SLA and height, the relationship was linear; for lumen fraction, it was quadratic. For wood density, the direction of the trait-abundance relationship was dependant on the abiotic context, that is, it shifted across a gradient in soil water content.4.Synthesis. Understanding the connections between traits and abundance is important for two reasons. First, there is an ongoing debate about the degree to which commonness and rarity are the result of drift among ecologically equivalent species or niche processes. These results suggest that there are non-random, trait-based processes affecting abundance and rarity. Secondly, species' traits have been shown to have a strong effect on photosynthesis and decomposition rates, mediated by the abundance of the species. The connections between traits and abundance presented here are crucial for scaling from measurements of species' traits to ecosystem-level processes. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.