U.S.-Madagascar Dissertation Enhancement: The Ranomafana Fragments Project

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9912116PattersonThis dissertation enhancement grant supports a US graduate student, Mr. Alex Dehgan, working under the guidance of Dr. Bruce Patterson, MacArthur Curator of Zoology at The Field Museum, to conduct a study in Madagascar on how different lemur behaviors affect their relative persistence in forest fragments, and the resulting impact on lemur demographics. Why do some but not all species become extinct when the size of their small fragmented habitat is reduced? Behavior already has an important role in determining an animal's ability to persist in the midst of habitat fragmentation, and Dehgan theorizes that behavior will also have a significant effect on how habitat fragmentation impacts a particular species' distribution on the landscape level. He also predicts that the extent of a species' behavioral flexibility (as determined by constraints developed through the course of its evolution), and the behavioral characteristics that it possesses, are important for determining its susceptibility to extinction, which will also affect its distribution across the landscape. Madagascar's lemurs exhibit an extraordinarily diverse range of behaviors, social systems, and ecological habits within a single, evolutionarily-related unit, and they provide a unique opportunity to understand the role that behavioral constraint has on the complex social organization of a species in the midst of fragmented landscapes. Dehgan will explore the linkage between behavior and biogeography to determine how behavioral differences among lemurs affect their relative persistence in forest fragments, and he will seek to uncover the proximate mechanisms behind such distributions. The study will be conducted on 12 subsets of lemurs in fragmented rainforest habitats in and around Ranomafana National Park. Dr. B. Andriamihaja, of the Madagascar Institute for Conservation of Tropical Environments, and Professor Berthe Rakotosamimanan, of the University of Antananarivo, will provide guidance to Mr. Dehgan on this project.The expected results should provide an important link between biogeographic patterns of extinction and local ecological processes and behaviors, which will create a better understanding of the mechanisms that drive local extinction and determine animal distributions, and will be an important new contribution to fragmentation theories. This project is being jointly funded by the Division of International Programs and the Division of Environmental Biology.