title: A trait-based approach to community assembly: partitioning of species trait values into within- and among-community components.
abstract: Plant functional traits vary both along environmental gradients and among species occupying similar conditions, creating a challenge for the synthesis of functional and community ecology. We present a trait-based approach that provides an additive decomposition of species' trait values into alpha and beta components: beta values refer to a species' position along a gradient defined by community-level mean trait values; alpha values are the difference between a species' trait values and the mean of co-occurring taxa. In woody plant communities of coastal California, beta trait values for specific leaf area, leaf size, wood density and maximum height all covary strongly, reflecting species distributions across a gradient of soil moisture availability. Alpha values, on the other hand, are generally not significantly correlated, suggesting several independent axes of differentiation within communities. This trait-based framework provides a novel approach to integrate functional ecology and gradient analysis with community ecology and coexistence theory.
authors.affiliation: Department of Integrative Biology, University of California, Berkeley, CA 94720, USA. dackerly@berkeley.edu
authors.forename: D D
authors.initials: DD
authors.lastname: Ackerly
authors.forename: W K
authors.initials: WK
authors.lastname: Cornwell
mesh_terms: D000222:Adaptation, Physiological; D017753:Ecosystem; D008954:Models, Biological; D010944:Plants / Q000033:anatomy & histology; D011157:Population Dynamics; D013045:Species Specificity