DISSERTATION RESEARCH: Trajectories of Genetic Change in Populations With Different Founding Sizes: Time Transects of Daphnia Populations in Two Upstate New York Lakes

种群减少对遗传多样性的长期影响已得到充分了解，但很少有研究在种群建立后立即检查遗传多样性的短期变化。这个项目的目标是比较三种食草浮游动物水蚤的遗传多样性的变化，这些水蚤从少量的建立个体和第四个由大量个体建立的种群中重新定居在一个湖泊。沉积物中长期休眠的水蚤卵记录了可以从沉积物岩心重建的种群年变化。在重新定居后的几个时间点上，四个“种群”中的每个“种群”的遗传多样性将被测量，以评估种群规模恢复后的变化。水蚤是水生生态系统的重要组成部分，具有控制藻类和鱼类食物来源的作用。一个种群对环境变化作出反应的能力取决于现有遗传多样性的水平。该研究将为水蚤如何响应环境变化和影响群落和生态系统过程提供重要的见解。它还将提供理论模型的经验检验，并有助于我们了解如何在自然种群中保持遗传多样性，这反过来将促进更适当的管理或保护计划。

Long-term effects of population reductions on genetic diversity are well understood, but few studies have examined short-term changes in genetic diversity in populations immediately after they have been founded. The goal of this project is to compare changes in genetic diversity in three species of the grazing zooplankter Daphnia that recolonized a lake from a small number of founding individuals with a fourth population that was founded by a large number of individuals. Long-lived dormant Daphnia eggs in sediments record annual changes in populations that can be reconstructed from sediment cores. Genetic diversity of each of the four "populations" at several time points following recolonization will be measured to assess changes as the populations recovered in size.Daphnia species are a key component of aquatic ecosystems, serving as a control on algae and a food source for fish. The ability of a population to respond to environmental changes depends on the level of genetic diversity present. This study will thus provide important insights into how Daphnia respond to environmental change and influence community and ecosystem processes. It will also provide empirical tests of theoretical models and contribute to our knowledge about how genetic diversity is maintained in natural populations, which in turn will foster more appropriate management or conservation plans.