Adaptation and Extinction in Changing Environments

当代自然人口面临着一系列具有挑战性的环境条件变化。种群适应新条件的能力在很大程度上取决于适应性特征背后的遗传变异模式。有一个完善的理论框架来分析适应的速度和轨迹。然而，缺乏足够的经验数据来扩展这一框架，以预测人口适应不断变化的条件的潜力。这项研究将对环境快速变化前后的淡水无脊椎动物种群进行直接比较，重点放在加利福尼亚州内华达山脉的一套高山湖泊上，这些湖泊已经知道鱼类的引入历史。将通过在引入鱼类之前从湖底沉积物中孵化卵并比较历史和当代种群来估计适应的速度和轨迹。鉴于目前人类对环境的影响水平，了解自然种群适应过程的限制是至关重要的。这项研究的结果将为自然种群的生态和遗传过程提供重要的见解，并将直接适用于自然资源和生物多样性的保护和管理，特别是在这些资源受到气候变化和入侵物种等现象的挑战时。在这些研究中获得的沉积物岩心将记录非生物和生物湖泊结构的历史变化，并将为各学科的研究人员提供宝贵的资源。研究和教育将通过培养研究生和本科生来整合。这项工作的结果将通过同行评议的期刊和与联邦机构的直接联系广泛传播。

0212487PfrenderContemporary natural populations are faced with a challenging suite of changing environmental conditions. The ability of populations to adapt to new conditions depends, in large part, on the patterns of genetic variation underlying adaptive characters. A well-developed theoretical framework exists for analyzing the rate and trajectory of adaptation. However, there is a lack of sufficient empirical data to extend this framework to make predictions about the potential for populations to adapt to changing conditions. This research will make direct comparisons of freshwater invertebrate populations before and after a rapid change in the environment, focusing on a suite of alpine lakes in the Sierra Nevada Mountains of California that have known histories of fish introductions. Estimates of the rate and trajectory of adaptation will be obtained by hatching eggs from lake-bottom sediments prior to the introduction of fish and comparing the historical and contemporary populations.Given the current level of anthropogenic influences on the environment, understanding the limits to the process of adaptation in natural populations is critically important. The results of this research will provide important insights into the ecological and genetic processes in natural populations and will be directly applicable to the conservation and management of natural resources and biodiversity, particularly when these are challenged by phenomena such as climate change and invasive species. Sediment cores obtained in these studies will document historical changes in abiotic and biotic lake structure and will be a valuable resource for researchers across a wide range of disciplines. Research and education will be integrated through the training of graduate and undergraduate students. The results of this work will be disseminated widely through peer-reviewed journals and direct contact with federal agencies.