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

实验室研究极大地促进了人们对特定基因如何参与受控条件下生物体衰老的生理过程的了解。 然而，为了更好地了解衰老的潜在机制，不仅需要识别基因，还需要识别影响野生生物衰老的环境因素。 该项目将利用对北极和亚北极地区的小雪雁种群进行 40 年研究的数据来研究雁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的种群密度对以后生存机会的影响，同时使用新开发的随机效应和混合模型来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生存的时空变化对雪雁种群动态的影响，并预测雪雁种群可能在何处扩大并威胁当地生态系统。 通过将现代统计方法与对独特标记个体的长期研究相结合，这项工作将有助于确定人口密度和环境条件在自由放养生物体衰老模式发育过程中的更普遍作用。 该种群模型将有助于同时阐明随着时间的推移调节鹅入侵新栖息地过程的人口统计过程，以及在初始入侵后调节雪雁密度的过程。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物种，并破坏北极生态系统，从而影响当地美洲原住民。 这项研究将在克里原住民为维持生计而使用的土地上进行。 原住民成员非常担心雪雁对栖息地造成的破坏，因为它会影响到他们传统生活方式的其他植物和动物。 该项目的研究结果可用于开发新方法，以减轻过多的雪雁对美洲原住民和农民的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.