Phylogenetic patterns differ for native and exotic plant communities across a richness gradient in Northern California

The assembly of local communities is the result of the tension between local, often negative, and possibly deterministic interactions, and larger-scale environmental or dispersal constraints or stochastic events (Berlow, 1997; Levine, 2000; Lovette & Hochachka, 2006). Larger-scale environmental conditions and dispersal limitation filter a larger pool of potential colonists into one that includes species with the appropriate suite of traits for arrival and persistence (Keddy, National Center for Ecological Analysis and Synthesis, University of California, 735 State St., Santa Barbara, CA 93101, USA, Department of Biological Sciences, University of Toronto, Scarborough, 1265 Military Trail, Scarborough, ON, Canada M1C 1A4, Department of Ecology, Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA, Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA, Ecology, Behavior and Evolution, University of California, San Diego, La Jolla, CA 92093, USA, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA