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

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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.