Dissertation Research: The Impact of Geographic and Environmental Heterogeneity on the Generation and Maintenance of Species Diversity in Hispaniolan Ground-dwelling Lizards

传统上认为，岛屿上生物多样性（在某一特定地点存在的物种数量）的调节过程是来自其他地区的殖民化和岛屿内的灭绝。 然而，大岛屿可能包含许多物种，其最近的亲属仅出现在同一岛屿上，这表明岛屿内的物种形成。 岛屿内物种形成可能是地理环境破碎化事件和生境类型的空间异质性造成的。 本文探讨了这两个因素在伊斯帕尼奥拉岛地栖蜥蜴进化多样性中的作用。 分子遗传学数据被用来检查内和5种Leiocephalus和3种Ameiva之间的遗传关系。 物种和种群水平的遗传学的背景下，使用地理信息系统技术来测试的假设，环境变化在物种形成中起着重要的作用，地面居住的蜥蜴的环境数据进行检查。 地质信息被用来测试蜥蜴多样化的历史环境破碎化的作用。 局部环境变化是用来检查地理变化的形态特征，认为具有适应性的significance.This研究明确识别环境和人口遗传条件，促进和维持进化多样性的岛屿动物群。 这项研究整合了来自不同来源的数据，以测试关于未充分研究的动物群多样化的假设。 这项研究也有利于当地学生在多米尼加共和国促进国际合作，提高进化和保护生物学的理解。

The processes regulating biodiversity (numbers of species that exist at a particular place) on islands are conventionally thought to be colonization from other areas and extinction within an island. Large islands, however, may contain many species whose closest relatives occur only on the same island, indicating within-island speciation. Within-island speciation may result from geographic environmental fragmentation events and spatial heterogeneity of habitat types. This dissertation examines the roles of these two factors in the evolutionary diversification of ground-dwelling lizards on Hispaniola. Molecular-genetic data are used to examine the genetic relationships within and among five species of Leiocephalus and three species of Ameiva. Species- and population-level phylogenies are examined in the context of environmental data using Geographical Information Systems technology to test the hypothesis that environmental variation plays a significant role in species formation among ground-dwelling lizards. Geological information is used to test the role of historical environmental fragmentation in lizard diversification. Local environmental variation is used to examine geographic variation in morphological characteristics thought to have adaptive significance.This study explicitly identifies environmental and population-genetic conditions that promote and maintain an evolutionarily diverse island fauna. The study integrates data from diverse sources to test hypotheses about the diversification of an understudied fauna. This study also benefits local students by fostering international collaborations in the Dominican Republic and enhancing understanding of evolutionary and conservation biology.