Phylogeography

In a collaborative project with the Field Museum of Natural History, Vahatra, and the University of Antananrivo, we are integrating field inventory activities with molecular phylogenetic techniques and geospatial analysis to investigate an area of the world that is biologically complex, poorly understood, and urgently threatened. This project is testing the hypothesis that the geological complexity of Madagascar, particularly its river drainage systems, has yielded a more complex pattern of species distributions and areas of micro-endemism than would otherwise be expected. We are investigating the connection between geological and geographic forces and patterns of vertebrate distribution and endemism. Madagascar has been designated as one of the most critical geographic priorities for conservation action, retaining less than 10% of the natural habitats that existed before human colonization. It is critical that information be obtained as quickly as possible to document the biota that occurs in the remaining and highly threatened forested areas of Madagascar, to gain an understanding of the evolutionary processes and associated distributional patterns that have shaped this diversity, and to use this information to help set conservation priorities. In particular, relatively few broad-scale vertebrate surveys have been conducted in western Madagascar outside of lowland and coastal forests. Our inventory activities have focused on the herpetofauna and mammals occuring at the survey sites and are tranlating into a better understanding of the presence, distribution, and abundance of numerous groups of Malagasy land vertebrates. Phylogenetic and biogeographic analysis of these animals, each with unique life-history and dispersal characteristics, are underway to identify areas of high endemism potentially associated with underlying geological features, and also to test for the role that rivers have played in generating patterns of vertebrate diversity and distribution. Analyses use informatic tools and can thus serve as a case study for the integration of field, lab, and geospatial analysis for understanding biogeographic patterns. The observed patterns from Madagascar will be immediately applicable for setting conservation priorities in this threatened and biodiverse environment and will further resolve known and newly-discovered species boundaries within multiple vertebrate groups.