Ecological and Evolutionary Bases of Extinction in West Indian Birds

本研究将验证种群的生态关系随着年龄的增长而朝着一致的方向进化的假设，这些变化最终导致栖息地宽度的限制和种群规模的减少，从而增加了灭绝的可能性。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上。先前的研究表明，与年轻种群相比，年龄较大的种群表现出有限的栖息地宽度和较小的种群规模，并且灭绝的风险更高。在这项研究中，一个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。每个种群通过长时间的进化趋势提供了一个时间片段。种群的时间顺序将允许重建栖息地宽度、种群密度和遗传多样性的历史趋势，这些通常适用于小型陆地鸟类，并检查它们在不同分类群中的一致性。这项研究将使我们更好地了解与物种灭绝有关的生态和进化过程。更好地了解岛屿上鸟类的灭绝过程，可以为在美国和世界各地日益分散的景观中保护物种数量下降提供框架。

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.