Comparative biogeography and diversification of birds on Madagascar

Islands are natural laboratories for studying the evolutionary and ecological processes of how species colonize and diversify in novel environments. The island of Madagascar is a biodiversity hotspot that is renowned for its distinctive avifauna -- an exceptional diversity of bird species found nowhere else. This project uses Madagascar as a model to address a fundamental question in biology: why some groups become much more diverse than others over time. The current bird fauna of Madagascar is the result of several independent colonizations from surrounding regions over historical time. Despite arriving in Madagascar millions of years ago, only half the native lineages have subsequently speciated within this large island. This project will focus on a comprehensive investigation of the poorly-studied bird diversity on Madagascar to determine what causes some groups to diversify while others fail to speciate. The study will produce a more accurate assessment of species diversity and diversification patterns, which is crucial for subsequent conservation measures in this highly threatened landscape. This project will promote international collaborations, education and training from high-school to postdoctoral stages, conservation policy, and public outreach activities.

With a strong collaboration of international scientists of diverse backgrounds and expertise, this project will examine all 43 endemic terrestrial avian lineages, including 14 independent radiations, using phylogenetic, biogeographic, and phenotypic data. This study has three main objectives. First, a robust foundation of systematic and biogeographic information for Malagasy avian lineages and their close relatives will be developed to provide more accurate assessments of species diversity within Madagascar, as well as insight into the timing and routes of colonizations. Second, analyses of how and why lineages change in ecology and morphology upon colonization of novel environments will be conducted. These analyses will include large-scale characterization of morphology, plumage, and climatic niche across Malagasy endemic species and their continental relatives to determine the importance of shared and clade-specific evolutionary responses to common environmental settings. Third, predictability of within-island speciation and adaptive radiation will be determined. The research will investigate the probability of radiation after colonization as a function of numerous predictors, including evolutionary lability of trophic morphology, environmental tolerance, and the intrinsic 'speciation potential' of individual clades. This project is a novel approach towards a comprehensive analysis of a biota and has broad implications for understanding the disparity in species richness across the evolutionary tree of life.