Ecological and Evolutionary Bases of Extinction in West Indian Birds

9419645 Ricklefs这项研究将测试的假设，种群的生态关系随着年龄的增长，在一致的方向发展，这些变化最终导致灭绝的可能性增加，通过限制栖息地的宽度和减少人口规模。为了解决这一假设，研究人员将使用历史和进化的方法。这项研究将集中在西印度群岛的陆地鸟类种群。以前的工作表明，老年人表现出有限的栖息地宽度和减少人口规模，并有更高的灭绝风险，比年轻的人口。在这项研究中，岛屿种群的进化年龄将通过它与邻近岛屿或大陆上最密切相关的姐妹种群之间的遗传差异来估计。每个种群都提供了一个时间片，通过长期的进化趋势。人口的时间顺序将允许重建的历史趋势，栖息地的宽度，人口密度和遗传多样性，一般适用于小型陆地鸟类，并检查其一致性的类群。 这项研究将使我们能够更好地了解与物种灭绝相关的生态和进化过程。更好地了解岛屿上鸟类的灭绝过程，可以为保护美国和世界各地日益分散的景观中不断下降的物种种群提供框架。

9419645 Ricklefs This research will test the hypothesis that ecological relationships of populations evolve in consistent directions with increasing age, and these changes ultimately result in increased probability of extinction through restricted habitat breadth and reduced population size. To address this hypothesis, the investigators will use an historical and evolutionary approach. The research will focus on land bird populations of the West Indies. Previous work has suggested that older populations exhibit restricted habitat breadth and reduced population size, and have higher risk of extinction, than do younger populations. In this study, evolutionary age of an island population will be estimated by the genetic divergence between it and the most closely related sister population on a neighboring island or on the continent. Each population provides a time-slice through evolutionary trends of long duration. The chronological sequence of populations will allow reconstruction of historical trends in habitat breadth, population density, and genetic diversity that apply generally to small land birds, and to examine their consistency across taxa. This research will allow us to gain a better understanding of ecological and evolutionary processes associated with species extinction. A better understanding of extinction processes of birds on islands can provide the framework for conservation of declining populations of species in an increasingly fragmented landscape through the US and the world.