RUI: Evaluating the Divergence-with-Gene-Flow Model in Natural Populations

史密斯9726425 热带雨林以其非凡的物种多样性而闻名。鸟类在这方面是突出的，因为热带雨林包含了一系列壮观的独特物种，在其他地方没有类似的。 然而，产生生物多样性的具体进化机制却知之甚少。在这项提议中，形态学和遗传学数据将被收集起来，以检验雨林物种形成的新假设。这一假说假定，生态交错带，即存在于中央雨林之外的草原上的小雨林片段，是新适应和新物种出现的栖息地，可以丰富中央雨林的生物多样性。自然选择在三个热带雨林鸟类物种的生态交错区人口将被量化，它们和中央雨林人口之间的形态分歧将被估计。 虽然这项研究解决了基本的进化问题，但它对撒哈拉以南非洲地区也有重要的保护意义。位于中央的雨林地区目前是保护工作的主要重点，而生态交错区由于过度放牧、焚烧和木材采伐而迅速消失，很少或根本没有保护它们。这样的生态交错区被认为是不太重要的，因为它们是纯粹的栖息地类型的马赛克，可能包含更少的物种和更小，更不稳定的人口。 然而，这些森林和稀树草原之间的过渡区域可能是进化新奇的重要来源，有助于雨林生物多样性。 \\Clm-06\debpop\POPBIO\ABSTRACT\SMP425.ABS

Smith 9726425 Tropical rainforests are renowned for their extraordinary diversity of species. Birds are prominent in this regard, as tropical rainforests contain a spectacular array of unique species having no parallel elsewhere. However, the specific evolutionary mechanisms that generate biodiversity are poorly understood. In this proposal, morphologic and genetic data will be gathered to test a new hypothesis for rainforest speciation. This hypothesis postulates that ecotones, small rainforest fragments that exist in the grasslands outside the central rainforest, are habitats in which new adaptations and new species appear that can enrich the biodiversity of central rainforests. Natural selection in ecotone populations of three rainforest bird species will be quantified and the morphologic divergence between them and central rainforest populations will be estimated. Although this study addresses fundamental evolutionary questions, it also has important conservation implications for sub-Saharan Africa. Centrally located rainforest areas are presently the main focus of conservation efforts, whereas ecotone regions are rapidly being lost due to overgrazing, burning and wood harvesting with little or no effort toward their conservation. Such ecotone regions are assumed to be less important because they are mosaics of pure habitat types that may contain fewer species and smaller, more unstable populations. However, it is possible that these transition areas between forest and savanna are important sources of evolutionary novelty that contribute to rainforest biodiversity. \\Clm-06\debpop\POPBIO\ABSTRACT\SMITH425.ABS