PARENT SESSION
Oral Session #77: Biodiversity and Ecosystem Function II.
Presiding: G. Chong
Thursday, August 8. 9:00 AM to 11:30 AM. Coconino Meeting Room, TCC.
Evolution of plant functional groups: implications for community ecology and global change.
Ackerly, David*,1, Schwilk, Dylan1, Cavender-Bares, Jeannine2, Mabry, Cathy3, Webb, Cam4, 1 Stanford University, Stanford, CA2 Smithsonian Environmental Research Center, Edgewater, MD3 Iowa State University, Ames, IA4 Yale University, New Haven, CT
ABSTRACT- Plant ecologists and systematists have often presumed that adaptive evolution of functional traits leads to high levels of convergence, and as a result plant functional groups (PFGs) have little correspondence with phylogenetic relationships. On the other hand, there are numerous taxonomic groups with distinctive ecological features, and closely related species often occupy very similar ecological roles. The synthesis of large comparative data sets, advances in seed plant phylogenetics, and new comparative methods now makes it possible to evaluate these contrasting perspectives in a rigorous quantitative framework. Using analyses of boreal, temperate, tropical and mediterranean-type ecosystems, we demonstrate that PFGs and individual functional traits show highly significant levels of phylogenetic conservatism - i.e., ecological similarity among close relatives. These patterns are observed from the community level, where the members of PFGs may be drawn from just one or two lineages, to the global level in the evolution of functional traits associated with old and diverse lineages. These results suggest that community assembly processes play a greater role than generally recognized as explanations for convergence of plant form in relation to climate. Additionally, robust inferences about the ecosystem consequences of changes in biodiversity should focus on traits that have arisen repeatedly in independent evolutionary origins of PFGs, especially for generalizations across floristically distinct ecosystems. Integrating evolutionary perspectives into the study of plant functional diversity is an important step towards this goal.
KEY WORDS: plant functional groups, comparative ecology, phylogeny