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是众所周知的，但很少有研究考察种群建立后遗传多样性的短期变化。这个项目的目标是比较放牧浮游动物大型水蚤的三个物种的基因多样性的变化，这些物种将一个湖泊从少数创始个体重新克隆到第四个种群，后者是由大量个体建立的。沉积物中长期休眠的大型水蚤卵记录了可以从沉积物岩心重建的种群的年度变化。在重新殖民后的几个时间点，将测量四个“种群”中每一个的遗传多样性，以评估随着种群规模的恢复而发生的变化。种群对环境变化的反应能力取决于现有的遗传多样性水平。因此，这项研究将为水蚤如何应对环境变化和影响社区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测试，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.