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Assessing Community Stability Through Comparative Phylogeography
Understanding how species responded to a common history of environmental change is essential for testing the stability of current species assemblages. Comparing phylogeographic patterns of co-distributed species can reveal the regional processes such as recolonization dynamics and habitat fidelity that drive species assembly. However, the application of comparative phylogeography to community ecology has been limited in its resolution until recently because robust analytic tools were lacking. This research will examine the seemingly incongruent evolutionary histories of 20 sympatric and widespread birds in European and Caucasian areas, including the Eurasian nuthatch (Sitta europaea), red-breasted flycatcher (Ficedula parva), great spotted woodpecker (Dendrocopos major), great tit (Parus major), willow tit (P. montanus), and others. To determine whether the avian species assemblage in the Caucasus has been historically stable, these researchers will dissect confounding factors that might explain incongruent mitochondrial gene trees into three distinct hypotheses: (1) natural selection; (2) geographic events; and (3) demographic factors. They use coalescence model-based approaches and multi-locus data to statistically test simultaneous divergence between the European and Caucasian populations and precisely estimate demographic parameters of each species. This research will contribute to move comparative phylogeography from a conventional descriptive mode to a new frontier based on statistical testing. More importantly, this research will demonstrate how biogeographic information can help to resolve a long-standing ecological debate over the historical stability of community structure. The group uses MSI’s computers to do genetic analysis, using the programs IMa and MSBAYES. These analyses take long periods to run, so that MSI’s high-performance computers are the necessary component for this project.