How do environmental conditions during development affect senescence and consequent population dynamics?

实验室研究极大地促进了对特定基因在受控条件下如何参与生物体衰老的生理过程的认识。 然而，为了更好地了解衰老的潜在机制，不仅需要确定影响野生生物衰老的基因，还需要确定影响野生生物衰老的环境因素。 该项目将利用40年来对北极和亚北极地区较小雪雁种群的研究数据，研究鹅种群密度的变化如何影响这些生物体的衰老速度。 这项研究将测量早期发育过程中人口密度对后期生存机会的影响，同时使用新开发的随机效应和混合模型控制未观察到的个体遗传变异，以基于捕获-标记-再捕获数据进行生存估计。 通过数据分析和建模，该项目将评估特定年龄存活率的时空变化对雪雁种群动态的影响，并预测雪雁种群可能扩大并威胁当地生态系统的地方。 通过将现代统计方法与对具有独特标记的个体的长期研究相结合，这项工作将有助于确定在自由放养生物体的衰老模式发展过程中人口密度和环境条件的更普遍作用。 人口模型将有助于同时阐明人口过程调节过程中的鹅入侵到新的栖息地随着时间的推移，和过程调节雪雁密度后，最初的入侵。高密度的迁徙雪雁对美国中部的谷类作物造成损害，将霍乱和流感等疾病传播给其他鸟类，并破坏北极生态系统，影响当地的美洲原住民。 这项研究将在克里族第一民族成员赖以生存的土地上进行。 第一民族成员非常关注雪雁造成的栖息地破坏，因为它影响到其他植物和动物，这是他们传统生活方式的一部分。 该项目的研究结果可用于开发新的方法，以减轻过多的雪雁对美洲原住民和农民生计以及北极和亚北极物种多样性的负面影响。

Laboratory research has contributed greatly to knowledge of how specific genes are involved in the physiological process of organism aging under controlled conditions. However, to better understand the underlying mechanisms of senescence, there is a need to identify not only the genes, but also the environmental factors that influence senescence of organisms in the wild. This project will make use of data from a 40 year study of a population of lesser snow geese in the Arctic and sub-Arctic to examine how changes in the goose population density affect the rate of senescence for these organisms. This research will measure the impact of population density during early development on chances of survival later in life, while controlling for unobserved individual genetic variation using newly developed random-effect and mixture models for survival estimation based on capture-mark-recapture data. Through data analysis and modeling, this project will assess the effect of spatial and temporal variation in age-specific survival on snow goose population dynamics, and predict where the goose population is likely to expand and threaten the local ecosystem. By combining modern statistical methods with a long-term study of uniquely marked individuals, this work will help identify the more general role of population density and environmental conditions during development on patterns of senescence in free-ranging organisms. The population model will help simultaneously elucidate demographic processes regulating the process of invasion of the geese into new habitats over time, and the processes regulating snow geese density after the initial invasion. High densities of migrating snow geese cause damage to cereal crops in the central United States, transmit diseases such as cholera and influenza to other avian species, and damage Arctic ecosystems which impacts local Native Americans. This research will be conducted on lands used by members of the Cree First Nation for subsistence living. First Nation members are very concerned about the habitat damage that snow geese are creating because it affects other plants and animals that are part of their traditional way of life. Findings from this project could be used to develop novel methods for mitigating the negative impacts of overabundant snow geese on the livelihoods of Native Americans and farmers, as well as Arctic and sub-Arctic species diversity.