Dissertation Research: Linking Ecology to Phylogeography: The Desmognathus Salamander Assemblage

9801305威尔伯为了保护生物多样性，了解和记录自然种群遗传变异的模式是至关重要的。群落生态学家的大量工作表明，物种相互作用可以影响种群大小和扩散速度的空间差异，这两个已知因素会影响种群遗传差异的大小。然而，种群遗传学家较少强调物种相互作用如何影响种群分化和物种形成的水平。有必要通过利用一种系统来弥合这一差距，在这种系统中，可以对影响流动模式和人口规模的因素进行机械性的理解。美国东部的火蜥属是研究物种相互作用及其在陆地进化中可能扮演的角色的模式系统。阿巴拉契亚山脉南部支持着世界火蜥蜴多样性中心。溪流通常支持四种金龟子，形成一个生态连续体，从大型的、更充分的水生物种到小型的、以陆地为主的物种。东部大陆的分水岭将含有四斑金线虫的溪流与不含四斑扇贝的溪流分开。这种大型捕食性火蜥蜴的存在本身就已知会影响其他更多陆地物种的分布和丰度。在这项博士论文研究中，亨利·M·威尔伯和学生莱斯利·J·里斯勒将利用现代遗传技术，使用线粒体DNA标记来解决这些豆属物种内遗传变异的空间尺度。这项工作强调生态和遗传工具的作用，以确定(1)表现出不同程度的陆生性的四个芒果属物种的主要生物地理边界，以及(2)物种相互作用对构建种群遗传变异程度的影响。

9801305 Wilbur To conserve biodiversity it is essential to understand and document patterns of genetic variation in natural populations. Much work by community ecologists has shown that species interactions can influence spatial variation in population sizes and dispersal rates, two factors known to impact the magnitude of genetic variation in populations. Population geneticists, however, have given less emphasis to how species interactions influence levels of population differentiation and speciation. There is a need to bridge this gap by utilizing a system in which a mechanistic understanding of the factors influencing movement patterns and population sizes can be developed. The salamander genus Desmognathus in the eastern United States is a model system for examining species interactions and their possible role in the evolution of terrestriality. The southern Appalachians support the world center of salamander diversity. Streams commonly support four Desmognathus species that form an ecological continuum from a large, more fully aquatic species to a small, predominately terrestrial species. The Eastern Continental Divide separates streams that contain D. quadramaculatus from those that do not. The mere presence of this large, predaceous salamander is known to affect the distribution and abundance of the other more terrestrial Desmognathus species. In this doctoral dissertation research, Henry M. Wilbur and student Leslie J. Rissler will utilize modern genetic techniques employing mitochondrial DNA markers to address the spatial scale of genetic variation within these Desmognathus species. Work emphasizes the contributions of both ecological and genetic tools to determine (1) the major biogeographic boundaries for each of the four Desmognathus species which exhibit varying degrees of terrestriality and (2) the influence of species interactions in structuring the extent of genetic variation in populations.