Systematics Section / ASPT
Lohmann, Lucia G. , Bell, Charles , Winkworth, Richard C. .
Bignonieae (Bignoniaceae): Insights into biogeography and ecological diversification.
The ecological importance and diversity of Bignonieae makes it an excellent model for investigating biogeography and ecological diversification in the Neotropics. This large group (360 species) is exclusively New World in distribution, reaching its greatest diversity in South America, but with range extensions into both Central and North America. The most striking feature of the group is the high diversity of lianas; Bignonieae contain more species of woody vines than any other group in the Neotropics. Within South America, Bignonieae occupy several broadly defined ecological zones: the dry savannahs of Central Brazil, the Atlantic Forest of coastal Brazil, the forests of lowland Amazonia, and the forests of western South America and Central America. Bignonieae are also extremely diverse in both reproductive and vegetative morphology. Here we use a broad-scale phylogenetic framework (one third of the species sampled for morphology, nuclear and chloroplast markers) to test alternative hypotheses on the biogeography and ecological diversification of this clade. These analyses indicate that the Bignonieae have a complex biogeographic history. Although the group most likely arose in the coastal forests of eastern Brazil, there has since been multiple transitions between ecological zones. Divergence times estimated using penalized likelihood and a Bayesian approach provide initial insights into the environmental factors that may have influenced these biogeographic patterns. Mapping of ecologically important characters onto the phylogeny indicates complex patterns of ecological evolution within Bignonieae; of particular interest are changes in growth habit, herbivore-plant interactions, pollination and dispersal syndromes. We discuss the possibility that these patterns of evolution are correlated with habitat shifts.
1 - University of Florida, Department of Natural History, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - Yale University, Department of Ecology and Evolutionary Biology, P.O. Box 208105, New Haven, Connecticut, 06520-8105, USA
3 - Missouri Botanical Garden, Center for Conservation and Sustainable Development, P.O. Box 299, St. Louis, Missouri, 63166-0299, USA
divergence time estimates
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 9:00 AM