photo by Kathryn Mercier
Breaking molds in Biogeography
Montane Atlantic Forest Phylogeography
Ecologists and evolutionary biologists have long been puzzled by the uniqueness of tropical montane biomes. Mountains are known outliers in biodiversity studies, showing excess endemism after accounting for abiotic variables such as area, primary productivity, topographic and climatic complexity. History has been suggested to underlie these observations, being often, yet loosely, associated with the positioning of mountains as outliers (Jetz and Rahbek 2002, Rahbek et al. 2007). This imprint of history on diversity is expected to be strongest for low dispersal organisms (Graham et al. 2006).
To provide insight on this subject, the current project studies biodiversity patterns and evolutionary processes in the highlands of Brazil’s coastal rainforest, using endemic reptiles and amphibians — both relatively low dispersal taxa — as model organisms. Central to the project is the recognition of two non-exclusive categories of processes: those that generate diversity, and those that maintain it afterwards. Target taxa are Vitreorana eurygnatha, V. uranoscopa, V. parvula, Enyalius brasiliensis, E. iheringii, E. perditus, and species of Placosoma, Caparaonia, Heterodactylus and Colobodactylus.
This work is funded by NSF (DEB 1120487)
In collaboration with:
Miguel Rodrigues, USP/Brazil,
Celio Haddad, UNESP/Brazil,
Craig Moritz, UC Berkeley
The project formalizes and tests the hypothesis that Brazil has high montane richness and excess endemism of reptiles and amphibians because mountains facilitate allo- or parapatric diversification due to topographic and environmental complexity and provide opportunities for increased population persistence and isolation under climatic fluctuations. Beyond the use of species distribution models and molecular ecology data, we are gathering information about the thermal tolerances of target taxa, providing an integrative view of species response to climate change.