Phylogenies of the seasonally dry tropical dry forest genera Ruprecthia (Polygonaceae), Coursetia, Poissonia, Chaetocalyx, Nissolia (all Leguminosae) and Loxopterygium (Anacardiaceae) show relatively old diversifications and a high degree of geographical phylogenetic structure where related species are found in the same or adjacent areas. This contrasts with more recent speciation patterns of the rain forest genera Inga and Renealmia, whose phylogenies shows low geographic phylogenetic structure. The implication is that the historical assembly of neotropical dry forest and rain forest communities may be different. Testing the generality of these patterns, and answering the fundamental question of whether the tempo and mode of evolution differs among distinct biomes will require further phylogenies of taxa from each biome.
Recent developments in ecology offer a new and exciting synthesis of the disciplines of biological inventory, systematics and evolutionary biology. For example, neutral ecological theory and data of relative species abundance permits estimates of rates of speciation and migration, two parameters that are central to understanding the historical construction of ecosystems. We aim to explore whether neutral ecological theory can be used to infer and contrast rates of speciation and migration from botanical inventory gathered in different biomes.
The ability of plants to make major ecological shifts governs their response to changing geological or climatic conditions. In the face of aridification, for example, plants adapted to wet forest would either have to adapt to the changing conditions or shift their distributions. Our research aims to determine the extent to which plants exhibit phylogenetic niche conservatism, i.e. an inability to adapt to changing environmental conditions which would be reflected in the fact that closely related species occupy similar ecological niches. Determining the extent of phylogenetic niche conservatism will allow us to make better predictions on how plants will react to future climate change.
Recent publications
Pennington, R.T., Lavin, M & Oliveira-Filho A. (2009). Plant diversity, evolution and ecology in the tropics: perspectives from seasonally dry tropical forests. Annual Review of Ecology and Systematics 40: 437-457.
Pennington, R.T., Richardson, J.A., Lavin M. (2006). Insights into the historical construction of species-rich biomes from dated plant phylogenies, phylogenetic community structure and neutral ecological theory. New Phytologist 172: 605-616 (invited Tansley Review).