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

9801305 Wilbur为了保护生物多样性，必须了解和记录自然种群中的遗传变异模式。 社区生态学家的大量工作表明，物种间的相互作用可以影响种群规模和扩散率的空间变异，这两个因素已知会影响种群遗传变异的大小。 然而，种群遗传学家很少强调物种间的相互作用如何影响种群分化和物种形成的水平。 有必要利用一个系统来弥补这一差距，在这个系统中，可以从机制上了解影响人口流动模式和规模的因素。 在美国东部的蝾螈属Desmognathus是一个模型系统，用于研究物种之间的相互作用及其在陆生动物进化中可能的作用。 南阿巴拉契亚山脉是世界蝾螈多样性的中心。 溪流通常支持四种Desmognathus物种，形成一个生态连续体，从一个大的，更完全的水生物种到一个小的，主要是陆生物种。 东部大陆分水岭将含有D. quadramaculatus从那些没有。 已知这种大型食肉蝾螈的存在会影响其他更多陆生Desmognathus物种的分布和丰度。 在本博士论文研究中，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，采用线粒体DNA标记，以解决这些Desmognathus物种遗传变异的空间尺度。 工作强调生态和遗传工具的贡献，以确定（1）主要的地理边界为每个Desmognathus的四个物种，表现出不同程度的陆生性和（2）物种的相互作用的影响，在结构的遗传变异的程度在人口。

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.